IMPRIMI potest:

Daniel H. Conway, S.J.
Praep. Prov. Missourianae

imprimatur:

Joseph E. Ritter
Archiepiscopus Sancti Ludovici

Die 28 Februarii 1955

Introduction to

The Philosophy of Being
GEORGE P. KLUBERTANZ, S.J.
Saint Louis University

New York

APPLETON-CENTURY-CROFTS, INC

Copyright, © 1955 by

APPLETON-CENTURY-CROFTS, INC.
All rights reserved. This book, or parts
thereof, must not be reproduced in any
form without permission of the publishers.

Library of Congress Card Number: 55-7164
585-2

Test edition copyright, 1952,
by George P. Klubertanz

PRINTED IN THE UNITED STATES OF AMERICA

Preface
This is an introductory textbook o£ metaphysics, an experi­
mental version of which has been in use for several years. Its
aim is to help a beginning student; it is not a profound study
directed to the scholar. The reason for writing a new textbook,
Thomistic in inspiration, is twofold; there is question both of
manner of presentation and of doctrine.
With many others I believe that metaphysics is not an analysis
of concepts. As an example of a purely conceptual analysis, I
would like to point out the procedure of those who take a con­
cept of being, compare it with a concept of nonbeing, and de­
rive the principle of contradiction. From this they deduce the
principle of sufficient reason. Then, by applying the principle of
sufficient reason to change, they deduce the principle of causality.
In this procedure, before we have ever experienced a cause, we
know that a cause is necessary for change. This entire procedure
of analysis and deduction seems to me to be hypothetico-dcductive (a priori), and far from St. Thomas’s method. “Aristotle,”
says St. Thomas,® “proceeded along another way. For first he
showed in many ways that there is something stable in sensible
things.”
According to St. Thomas, the human intellect must begin with
sensible tilings, and hence all principles must somehow be found
in sense experience. The discovery of principles is an induction,
as I hope to prove in this text. But there is no danger of empiri­
cism or sensism, if we remember that point on which Aristotle
and St. Thomas were ready to stake their whole philosophy,
namely, that sensible things are potentially intelligible. If this
• On Spiritual Creatures, art. 10, ad 8, trans. Mary C. Fitzpatrick and
John J. Wellmuth (Milwaukee, Marquette University Press, 1949), p. 122.
v

vi

PREFACE

means anything, it means that sensible things can be understood
as being. How we can build a metaphysics upon our experience
of sensible things may be difficult to explain, but according to
St. Thomas we must find in the being of our direct experience
all the intrinsic principles of being. Being is simply the first
principle; there arc other principles which we find in concrete
being through the intelligible light of being. These principles are
connected with being, but they cannot be deduced from it by any
purely conceptual process.
The decision to base metaphysics on sensible being as it is
presented to us in immediate experience entailed other departures
from systematized Thomism. Act and potency could no longer be
presented according to their “concepts,” but had to grow out of
the consideration of substance and accident, matter and form,
essence and the act of existence. Similarly, analogy turned out
not to be a simple scheme of prediction but a complex group of
relations. Naturally, in an introductory textbook, the historical
and textual evidence that confirms the experiential evidence can­
not be presented; the reader—student or teacher—is referred to
the last chapter and to the studies there cited.
With regard to the manner of presentation, this book is not
“St. Thomas made simple.” St. Thomas’s thought is not simple,
and attempted simplifications usually end by simplifying the po­
sitions and letting the reasoning go. The method of this book
attempts to provide for the necessary introductory character of
the course by selecting only a few of the problems of metaphysics
for study and by giving as concrete a presentation of the evi­
dence as possible.
As far as course work is concerned, these suggestions can be
made. In the preliminary presentation, the first three chapters
should be covered rapidly and then taken thoroughly at the end
of the course by way of review. The course could also be begun
with Chapter IV, without any serious difficulties. It would even
be possible to begin with Chapter IX, but this procedure would
entail quite a few difficulties in teaching. It is also suggested that

PREFACE

vii

Chapters XI to XIII inclusive be studied very briefly, and that,
if the time is short, preference be given to a review of the first
ten chapters. Chapter XIV is not intended to be taken as such
in a regular class; pertinent parts can be taken up in connection
with earlier parts as indicated by the cross references to the last
chapter, and better students can be directed to study parts of it
privately. The footnotes are in general of two types: cross refer­
ences and clarifications. The cross references will help the stu­
dent to become aware of the connections between the various
topics. The explanatory footnotes will sometimes be helpful for
classwork, but in the main they are not intended to be given full
attention by all the students the first time through the book.
Better students can find in them suggestions for further study and
comparison with what they have learned. In review classes, the
footnote material will often be useful, but the individual teacher
will be able to judge the capabilities and interests of particular
classes.
Some passages from St. Thomas are included in the text. It is
presumed that the student will have ready access to the English
translations of St. Thomas and that readings be assigned from
the passages indicated in the readings at the end of the chapters.
Perhaps the review sessions arc also the best time to study the
passages from St. Thomas more thoroughly.
A word to the student may be in order here. Philosophy is a
distinct kind of knowledge, different from history, science, lan­
guages, mathematics, and so on. Hence, it must be studied in a
special way. Particularly in the philosophy of being, the great
need is for understanding. There arc few new facts to be learned,
but explanations must be grasped. Definitions and proofs need to
be memorized; at best they are but tools. Knowing the answer
the teacher wants is by no means the same as knowing phi­
losophy. Real knowledge of philosophy is an intellectual under­
standing, an insight. It is something like a contemplation, a long,
hard look at reality and its intelligible manifestations. There arc
no mechanical rules or formulas that can substitute for under­

viii

PREFACE

standing. Time, thinking, reading, discussion—these will gen­
erate the habit of metaphysics. To many students, philosophy
will seem at first a strange pursuit. But if it is faithfully worked
at, it can be one of the truly rewarding experiences of education.
If the author were to mention by name all who have helped
him in the learning of metaphysics or the writing of this book, he
would have to mention some who would not agree with the final
form this book has taken. Prominent among those who have
given suggestions and constructive criticism have been the
teachers in the 14 schools where the preliminary edition was used.
As a result of the very thorough classroom testing and of extensive
discussion and correspondence with valued friends, tliis present
edition is almost in its entirety a new book. The mature re­
flections of one’s teachers, one’s colleagues, and even one’s
students influence the writing of any philosophical work. Yet in
spite of this social or group aspect which philosophy has in com­
mon with the sciences, there is a highly personal character to
all philosophical thinking, so that in the last analysis no one
except the author of a philosophical work is responsible for its
inadequacies.
G.P.K.
Saint Louis University

Table of Contents
PREFACE...................................................

V

I. INTRODUCTION
1. The philosophy of being and other kinds of knowl­
edge ...................................................................
1
2. The philosophy of being and the other parts of
philosophy......................................................
8
3. Philosophy and religion........................................10
4. Characteristics of organized, scientificknowledge .
14
5. Thomistic philosophy........................................ 15
6. Definitions..........................................................17
7. Readings................................................................19
II. THE MEANING OF “BEING”

•

8. Various senses of the word real............................ 24
9. The question: “What is it to be real?”....
25
10. The Thomistic answer to the question: "What is
it to be real?”................................................... 34
11. Demonstrative knowledge and abstraction ...
36
12. Our knowledge of being as being............................... 39
13. The first principles of knowledge............................... 44
14. Definitions.................................................................. 46
15. Summary of the argument...........................................47
16. Readings
.................................................................. 48

III. THE FIRST ANALOGY OF BEING
17.
18.
19.
20.
21.

The fact of knowledge in common...............................53
Univocation and its basis.......................................... 53
Is being a universal?................................................ 54
Being is analogous...................................................... 56
Definitions.................................................................. 61
ix

TABLE OF CONTENTS

X

22. Summary............................................................... 61
23. Readings............................................................... 62

IV. BECOMING—CHANGE—MOTION

24.
25.
26.
27.
28.
29.

The implications of change.................................. 64
Identity, distinction, and difference ....
A changing thing has reallydistinct components .
Definitions......................................................... 72
Summary............................................................... 73
Readings............................................................... 73

66
68

V. THE INTRINSIC PRINCIPLES OF CHANGE AND
BEING: I. IN PARTICULAR

30. Accidental change and the substance-accident com­
position of being..................................................... 76
31. Substance and accident as beings by analogy . .
78
32. Substantial change and the matter-form compo­
sition of substance............................................... 80
33. Individuals in a species and matter-form compo­
sition .............................................................................. 83
34. That-which-is and the act of existing (esse) .
88
35. The distinction between power andactivity . .
91
36. Definitions.................................................................. 93
37. Summary of the argumentation............................... 95
38. Readings........................................................................ 96
VI. THE INTRINSIC PRINCIPLES OF BEING: II. AS
ANALOGOUSLY ONE

39.
40.
41.
42.
43.

Comparison of the three sets ofintrinsic principles 101
Theorems of act and potency...........................104
Concluding remarks about actand potency . . 112
Exercise.............................................................. 116
Readings.............................................................. 117

VII. THE EXTRINSIC PRINCIPLES OF BEING: I. THE
AGENT

44. Principles of change..................................................... 119
45. Causal factors........................................................... 121

TABLE OF CONTENTS

46.
47.
48.
49.
50.
51.
52.
53.
54.

XI

The causality of the agent or efficient cause . . 121
Types of agents: univocal and equivocal causes . 126
Types of agents: principal and instrumental causes 128
The exemplar cause..................................................... 130
The theorem of causality......................................... 130
The analogy of eminence in causality .... 135
Definitions................................................................ 137
Proofs....................................................................... 140
Readings...................................................................... 140

VIII. THE EXTRINSIC PRINCIPLES OF BEING: II. THE
GOAL OF ACTION
55.
56.
57.
58.
59.
60.

The goal of action..................................................... 144
Finality in being..................................................... 153
Chance...................................................................... 154
Definitions................................................................ 157
Proof............................................................................ 158
Readings.......................................................................158

IX. GOD, THE CAUSE OF LIMITED BEING
The problem.............................................................160
Solutions...................................................................... 161
The question of knowledge................................... 163
The question of proof...............................................165
Evidence and argumentation (I)............................. 168
Evidence and argumentation (II)............................. 169
The analogy of participation................................... 170
Answers to objections............................................... 174
The creative intellect and the finality of natural
causes...................................................................... 176
70. Definitions................................................................ 179
71. Readings...................................................................... 180

61.
62.
63.
64.
65.
66.
67.
68.
69.

X. THE TRANSCENDENTAL^

72.
73.
74.
75.

Being is a transcendental......................................... 186
Possibles...................................................................... 188
Beings of reason and pure intelligibilities . . . 190
The transcendental “one”......................................... 193

TABLE OF CONTENTS

xii

76.
77.
78.
79.
80.
81.

The transcendental “true”........................................ 195
The transcendental “good”........................................ 199
The transcendental“beautiful”............................... 203
Definitions.................................................................204
Proofs...................................................................... 205
Readings.......................................................................205

XI. THE PREDICAMENTS: SUBSTANCE AND SUPPOSIT
The predicamentsin general.................................... 212
Substance.................................................................218
Supposit andperson...................................................... 220
Digression on the backgrounds of the problem of
personality................................................................ 222
86. Definitions.................................................................222
87. Readings....................................................................... 223

82.
83.
84.
85.

XII. ACCIDENTS
QUALITY

IN

GENERAL:

QUANTITY

AND

88. The nature of accidents...............................................229
89. Quantity and quality...............................................234
90. Digression: the substance-accident distinction and
the theology of theEucharist.................................... 236
91. Definitions................................................................ 236
92. Readings.......................................................................236
XIII. THE FORMALIZED ACCIDENTS

93.
94.
95.
96.
97.
98.

Relation.......................................................................239
Action and passion.................................................... 247
When, where, situs, andhabitus............................... 250
Definitions................................................................ 252
Proof............................................................................ 253
Readings.......................................................................253

XIV. CORRELATIONS

99. Introductory note..................................................... 257
100. Ontological and eonstructural knowledge . . . 257
101. Metaphysics, experience, and spontaneous knowl­
edge .............................................................................264

TABLE OF CONTENTS

XÍÜ

102. Digression on “common sense”...........................269
103. Metaphysics and humanistic knowledge (liberal
education).......................................................... 273
104. Metaphysics and other scientific knowledges . . 276
105. Metaphysics and the faith................................ 278
106. Thomism and other philosophies.....................281
107. The constructural knowledge of being....
282
108. The analogy of analogy...................................... 286
109. St. Thomas and the Thomists.......................... 290
INDEX OF PASSAGES FROM ST. THOMAS AQUINAS......................................... 293

INDEX OF NAMES AND SUBJECTS........................................................................... 295

------------------------------ ...-------- _

CHAPTER I

Introduction
1. The philosophy of being and other kinds of knowledge
A college student has already learned many things and may
often feel that what he knows is more than enough to last a
lifetime. A student may be fully aware of the necessity of con­
tinuing his studies in the field he has chosen for his special work;
but why take up another subject which, at first sight, will have
no practical value? Before this question can be answered, it is
necessary to consider the relationships among the various kinds
of knowledge and of these various kinds of knowledge to a
human being.1
First of all, we can have different modes of knowledge about
a particular subject (for example, life, number, man). The first
mode of knowledge is that of unreflective, untutored, day-to-day,
spontaneous knowledge. For examples we can consider our di­
rect acquaintance with the objects of daily experience—food,
weather, clothes, other people, animals, machines. This kind of
knowledge is similar to those immediate, simple judgments in
the practical order which are often called “common sense.”2
We are here going to consider the theoretical knowledge that
we derive from common experience. In our day-to-day dealing
with concrete reality, wc have an incontrovertible evidence for
the existence of a distinct world of extra-mental reality. We see
that this world is made up of tilings which are also distinct from
1 The three modes of knowledge are considered more fully in Chap. XIV,
secs. 101 and 103.
’The term "common sense” is discussed in detail in sec. 102.
1

2

CHAPTER I

[1]

each other; that these things belong to different kinds or classes;
that they undergo change; and that there arc different kinds of
change. These truths are more or less the immediate results of
perceptual experience. Moreover, immediate experience delivers
to us a massive, constantly repeated and reinforced evidence for
some general propositions ( for example, that changes arc brought
about by causes), and some few conclusions (for example, that
the world is dependent upon, and under the control of, some
greater being). Of these things and truths even the untaught and
unreflective man is certain.
Spontaneous knowledge, however, has very definite limitations.
The certain truths that it contains are isolated from each other;
spontaneous knowledge is not organized through principles. The
reflections of an undisciplined mind tend to be rambling, discon­
nected, and repetitive. Spontaneous knowledge very often cannot
tell why it has the truth; its reasoning is often implicit. Spon­
taneous knowledge is unable to defend its truths against objec­
tions and attacks, and can easily be weakened and even over­
thrown by passion. Hence, even when spontaneous knowledge
is true, this truth is at a subscicntific level of development.
The second mode of knowledge is refined. For example, knowl­
edge in the second mode is that which an educated person has
of human nature through poetry, history, drama, and so forth;
briefly, it can be designated as the product of a liberal education.
This refined mode of knowledge has two essential characteristics.
One is that it possesses some organization through principles. The
other is that it is not merely knowledge; it is addressed to the
total human personality, and for this reason it often is called
“humanistic knowledge.” A liberally educated person has learned
intellectually; he has also developed his sensory, emotional, and
volitional life. Because humanistic knowledge usually develops
out of a contact or interaction with culture, it is more complete
than spontaneous knowledge, for it draws on the contributions
of a social group. For the same reason, many of the crude errors
and misconceptions of spontaneous thinking are eliminated from

[1]

INTRODUCTION

3

refined knowledge. Very many men find this mode of knowledge
sufficient for living a full human life and never achieve any other
type of knowledge.
Humanistic or refined knowledge, though it is a necessary and
irreplaceable part of a full human development, has some limita­
tions as far as knowledge itself is concerned. As knowledge, it
does have some organization, but its organizational principles
are either understood in the spontaneous mode or in terms of
concrete imagery, its structure tends toward tire rhetorical, and
its deepest understanding tends toward metaphor or myth. In
humanism, man has found one pole of his perfection, and yet
there is a direction in which the full rationality of human reason
has not yet been reached.
The mind’s drive toward the conscious exercise of its power
to know has led to the development of a third mode of knowl­
edge, the scientific.3 This mode of knowledge is relatively com­
plete and has freed itself from the subtler as well as the grosser
errors of everyday knowledge. Moreover, it is organized by
intrinsic principles that are proper to its subject, and therefore
it can really demonstrate its conclusions. As a further conse­
quence, it is at least to some extent a certain knowledge.4 The
most familiar examples of organized knowledge are the natural
sciences. In physics, for example, there is first of all a carefully
checked and relatively complete body of facts; there is secondly
an organization of these facts into systematic units by means of
general principles and theories: all the facts about light are uni­
fied and put into relation with each other through the systematic
theory of light; all the facts about falling bodies and planetary
motions are unified through the laws of motion. It is only when
• In this book, the term “science’’ is used in its modern, restricted sense,
as a name for a special kind of demonstrative, “third-mode” knowledge.
The adjective, "scientific,” however, is used to mean not only “belonging to,
pertaining to, a science” hut also “similar to a science.” Thus, the entire
group of third-mode knowledges can be called “scientific knowledges,” be­
cause all of them aie similar in having an organized structure, and “science’
is best known to most people.
* Selected Passages, Ño. 3, touches on this point.

4

CHAPTER I

[1]

knowledge has been developed into the scientific mode that we
can clearly distinguish the various kinds of knowledge.
Every knowledge is about something, and most knowledges
deal directly with something real. What a knowledge is about
is called its subject or “subject matter”; for example, arithmetic
deals with numbers, biology with living things, and so on. This
is the vaguest and most general way to speak of knowledge, and
it is so vague that it is of little practical use. If we want to speak
a little more accurately, we can describe a knowledge by nam­
ing the various tilings that it deals with: arithmetic deals with
the numbers 1, 2, 3, and so on; biology, with many kinds of
living things.
If we wish to distinguish demonstrative knowledges, we must
examine what they intend to investigate about their subjects, and
how this is to be done. These questions ask about the objects5 of
a demonstrative knowledge. The material object designates in­
determinately and in its entirety the subject of a knowledge
(especially of a demonstrative knowledge) in relation to the
propositions that can be made about it. By the adjective “mate­
rial” we do not imply that there is matter in the make-up of the
subject; we mean to indicate that the object is to the knowledge
as materials are to an artist or craftsman. For example, we might
say that the material object of the natural sciences is “what can
be known about the things around us which come into being by
natural processes”; the object of the social sciences is “what can
be known about men in their relationships to each other, espe­
cially as they are formed into groups.”
When we look at demonstrative knowledges as they have been
developed today, we find that there are distinct knowledges
“The term “object" is used in many different meanings. In modern usage
it may mean “tiling,” "thing presented to knowledge," "purpose or goal.”
When it is used in the philosophy of human nature to distinguish powers,
it means “that which moves a potency to its act." When it is used in meta­
physics and epistemology to distinguish kinds of knowledge, various differ­
ent meanings are used by different authors. The one used in tile present
book arises from an attempt to simplify and yet to be sufficiently in harmony
with other usages as to help the student to read other works.

[1]

INTRODUCTION

5

about the same subject (for example, biology, psychology, and
philosophy of human nature have, at least in part, the same sub­
ject, man). And they all intend to find out what can be known
about man; they have the same material object. What then is
the difference? Their ways of knowing, and the kind of knowl­
edge they obtain, are different; this sort of difference is the object
considered explicitly as it is knowable. That is why the manner
of our knowledge, the principles we use, the kind of argumenta­
tion we employ, are included in the notion of formal object. To
give a complete and accurate description of a knowledge, we
designate its material object as specified by the formal object:
this we call the “proper object” of a knowledge.
We can now give a preliminary and descriptive definition of
the philosophy of being. Its subject is reality; its material object
is what can be known about all real things; its formal object,
what can be known about all real things “as real”; and so its
proper object is what can be known about the real inasmuch as it
is real.8 We can see at once that most other organized knowl­
edges deal with, or are concerned with, some particular aspect
or part of reality (for example, physics, biology, chemistry).
Thus at first sight the philosophy of being seems to differ from
all other organized knowledges by its material object, for it deals
with all of reality, and they deal with aspects or parts of reality.
But we may well wonder whether there is anything more to
the philosophy of being than the sum total of all other knowl­
edges. Is there any room for, and any point to, an alleged or­
ganized knowledge about the real as such? Some people (posi­
tivists, empiricists) say that there is no such thing at all as the
philosophy of being. “It is usually supposed that if you publicly
dismiss ontology, it will go away quietly; but this is foolish­
ness.” 1 Others hold that there is a kind of collected and digested
summary of all the various kinds of particular knowledges and
‘Selected Passages, No. 1, takes up this point.
* James K. Feibleman, Ontology ( Baltimore, The Johns Hopkins Press,
1951), p. 100.

6

CHAPTER I

[1]

that this digest could be called a philosophy of being. But per­
haps the best preliminary way to see that there is a place for
a distinct and special kind of knowledge called “the philosophy
of being” is to look at the type of question that is asked in it.
For example. What is it to be real? Why do we call a thing a
being? Is there more than one kind of reality? What is change?
Is every being changeable, or is there unchanging permanent
reality? Is being simple or complex? Is being limited or un­
limited? Is a limited being caused? How many kinds of causes
are there? What are truth and goodness? What is an individual?
A person? Is there a cause of the various beings which we ex­
perience? Is this cause God? What kind of being is God, and
what is His relationship to us? Even if we do not understand
these questions now, it is easy to see that no other organized
knowledge asks or answers them and that no collection or sum­
mary of other knowledges touches on them.
For this reason there are persons who admit that there is a
kind of knowledge called the philosophy of being but think it is
an unnecessary luxury, like poetry or lacework. We may put this
position in the form of a concrete question: What does the philos­
ophy of being mean to me? What difference does it make to me
whether I bother answering these questions at all or answer
them wrongly? Here a distinction must be made. Some kind of
knowledge of the real, at the lowest level of our everyday knowl­
edge and as the implicit background of all our other knowledge,
is the absolutely indispensable condition of all other knowledge
in any mode—this we hope to see more clearly at the end of the
course than we do now. But even now we can see that in a
sense every man is implicitly a philosopher. P’or everyone dis­
tinguishes between fact and fiction, between dream and reality;
everyone deals with reality, takes it quietly or rebels against it.
These distinctions and modes of action include and involve phil­
osophical knowledge in the everyday mode. For example, the
distinction between fact and fiction is actually made even by
uneducated persons, though not ver}' clearly and accurately; and

[1]

INTRODUCTION

7

these same persons implicitly accept the principle of contradic­
tion in all their thinking and doing. Furthermore, we see that
many persons know, with everyday or even refined knowledge,
that there is a God, but they are unable to prove it in any organ­
ized way. Is it not enough to know that there is a God without
being able to prove it? Can we not rest satisfied with our every­
day and our refined knowledge of the real (supported and en­
larged by faith) and let it go at that? It is true that not every­
body needs to have philosophical knowledge in an organized
way, just as not everybody needs to know higher mathematics.
But suppose no one explicitly knew the philosophy of being. The
probable result would be the acceptance of a large amount of
error and superstition by many people. For everyday and re­
fined knowledges contain a greater or smaller percentage of
error, and they are incomplete. They contain no safeguards
against error; they do not enable a person to meet difficulties
and objections. Hence, a person who is trying to become an
educated man or woman and who consequently will meet with
erroneous philosophical positions both in his reading and in his
later life needs for bis own sake to know at least the essentials of
philosophy. Intellectual ability, moreover, is a responsibility as
well as a gift. The common good requires that some of those
who can learn philosophy do so.
There is another extrinsic, personal advantage in the study
of philosophy. A person cannot be mature and confident without
an organized and unified outlook on life. A person who is highly
educated only in certain specialized areas finds that the world
for him is broken up piecemeal. How is he to organize and
master this multiplicity? If he attempts an organization by means
of limited principles—limited principles are all that can be found
from a specialized (that is, partial) point of view—something
will have to be left out. He can organize and order all his knowl­
edge and all the aspects and parts of the world that confront him
only from the point of view of, and by means of the principles
discovered in, his study of philosophy.

8

CHAPTER I

[2]

2. The philosophy of being and the other parts of philosophy
Besides the philosophy of being there are other branches of
philosophy. Frequently these divisions are used: logic, which
deals with second intentions (beings of reason) that pertain
to correct reasoning; cosmology (the general philosophy of na­
ture), which deals with a particular kind of real being—that is,
material, corporeal, or changeable essence as such—and con­
siders the nature and activities of this kind of thing; the philos­
ophy of human nature, which deals with the real being, man, and
explicitly treats of his nature and activities; epistemology, which
deals with knowledge itself; ethics, which deals with human
action. These various parts of philosophy differ in material object
among themselves and also differ from the philosophy of being,
which deals with all real beings.
Since each of the other philosophical knowledges, however,
does within limits deal with something which is, they must all
be governed by metaphysics. The principles and conclusions of
the philosophy of being are all-pervading. Not that metaphysics
can substitute for other kinds of knowledge, not even for the
other parts of philosophy; nor can the truths of any other branch
of knowledge be deduced from those of metaphysics. This nega­
tive description must suffice for the present; we will again con­
sider the relationship of the philosophy of being to other knowl­
edges at the end of the book.8
One particular problem of relationship, however, can be
taken up at this point. In order to be a complete knowledge of
the real, metaphysics must also deal with the absolutely first prin­
ciple of all other being, that is, with God. The philosophical
study of God is often given a special name, that of “natural
theology,” and is usually studied in a distinct course under that
name. Is it distinct, though, from the philosophy of being in the
* Selected Passages, No. 2, takes up this point. For a fuller development,
sec below, sec. 104.

[2 ]

9

INTRODUCTION

same way that logic, the philosophy of human nature, or ethics
is? Natural theology treats of divine things not as the subject
of tlie science but as the principle of the subject (that is, being
itself); consequently, it cannot be adequately distinct from the
philosophy of being. The philosophy of being, taken in its full
sense, deals with whatever is in its entirety and with all the
principles of the real. For convenience, however, and especially
for the advantage of the beginning student, we divide the philos­
ophy of being into two “integral parts”:9 the introductory philos­
ophy of being and natural theology, which is the complementar)'
and crowning part of the whole philosophy of being. The fol­
lowing may clarify the relation:
THE WHOLE

The philosophy of being is a
distinct philosophical knowledge
dealing with the real as real and
with the principles and character­
istics of the real.

THE PARTS

Natural theology deals with un­
caused reality as real and as the
first principle of all other reality.

Introductory philosophy of be­
ing starts with the real which in
fact is caused, and indeed with the
caused sensible real. From a study
of this kind of being, we derive
our knowledge of what the real
is, of what its characteristics or
properties are, and of its princi­
ples as this kind of being. Finally,
since this kind of reality pre­
cisely as real shows itself to be
caused, we can move by way of
causality to a knowledge of the
uncaused Real as the first princi­
ple of the reality of experience,
and so to a knowledge of that
Reality as real.

• An “integral part” is a quantitative or quasi-quantitative part, which to­
gether with the rest of the parts makes up a whole by addition and so can­
not be predicated of the whole; an integral part can continue to exist when
separated from the whole (though it may change its nature in being sepa­
rated).

10

CHAPTER I

[3]

3. Philosophy and religion
Philosophy and religion sometimes seem to concern the same
things. For example, religious teachings mention good and evil,
God, the immortality of the soul, the obligation to do good and
avoid evil. Philosophy also deals with these same points. Does
that make religion and philosophy the same thing? 10
By religion, in general, we mean "the sum total of man’s rela­
tions to a higher being on whom man depends in some way.”
These relations include both knowledge and action (and the
latter is made up of a moral code and some kind of cult or form
of worship). Religion can arise as a result of men’s effort to find
out the basic truths about themselves and the universe and as a
result of their desire to act in accord with what they know. A
religion that arises in this way is called a "natural religion.” In
our Western culture, however, this is not what the term “religion”
generally connotes. Ordinarily, religion means “revealed re­
ligion,” that is, a religion which arises both from man’s own
efforts and a revelation from God. The content of revelation, as
far as knowledge is concerned, may include both objects that
man’s reason could reach by itself and objects that arc entirely
beyond the powers of human reason. These latter truths can be
known only by faith (the free intellectual acceptance of a truth
on the authority of another); the former objects can be known
either by reason or by faith.
When we ask, “Arc religion and philosophy the same thing?”
obviously we are asking about the relation between religious
knowledge and philosophy. To answer this question, we must
distinguish not only between natural and revealed religion but
also between material and formal objects. As we saw in section
1, knowledges are defined by their proper objects and distin­
guished one from another particularly by their formal objects,
even when they have the same material objects. Now, all the
knowledge-objects of a natural religion are also dealt with by
10 For a fuller discussion, sec below, sec. 105.

[3]

INTRODUCTION

11

philosophy; but philosophy deals with some objects (for exam­
ple, the nature of knowledge itself) with which a natural
religion does not deal. The knowledge-objects of a revealed reli­
gion, on the other hand, are partly held in common with philos­
ophy and partly are special to revelation (for example, the
Trinity, the Incarnation). Thus there are some common material
objects for natural religion, revealed (supernatural) religion, and
philosophy.
What about the formal objects of these three knowledges? The
knowledge contained in natural religion may be held on the
ground of a man’s own personal insight (on any one of three
levels of knowledge) or on the authority of another and wiser
man. The knowledge of natural religion, therefore, does not
necessarily involve personal insight; it is merely necessary that
it contain truths attainable by human reason. Hence, in the case
of a philosopher, his natural religious knowledge and his philos­
ophy would be the same, even though natural religious knowl­
edge is not necessarily a demonstrative knowledge. On the other
hand, it is the special characteristic of a revealed religion that
its truths be accepted by faith. Now, faith is knowledge resting
on the authority of a witness, such that the evidence for the
assertion bears directly not on the truth of what is known but
on the character of the witness as such (that is, on his knowledge
and truthfulness). When the revealing witness is God himself,
the faith by which we accept His revelation is supernatural faith.
But in philosophy the situation is different. All the branches of
philosophy (indeed, all organized knowledges except history
and theology) rest on evidence that bears directly or indirectly
on the truth of what is known. A philosopher as such takes some­
thing as true because there is evidence bearing on the truth
itself; he does not take something as true because someone has
said it. On the other hand, the knowledge of revealed religion
is taken as true precisely because God has said it. Consequently,
philosophy and revealed religion have formally different objects
and so are really distinct one from the other.

12

CHAPTER I

[3]

One consequence of this difference is that a man who has
everyday knowledge plus faith can tell an error from the truth.
He cannot, however, tell why an error is an error; he cannot
answer an objection; he cannot easily apply his knowledge to
unforeseen situations or difficult problems. This is just the kind
of thing a philosopher as such can do. Hence, it is practically
necessary', even from the viewpoint of revealed religion, that
some believers become skilled in philosophical thinking. So
philosophy indirectly helps faith. Secondly, a believer, because he
has an intellect with an innate drive toward understanding,
wants to understand the content of his faith as much as possible.
The organized effort to understand faith is called theology, and
a large part of scientific theology consists in the use of philo­
sophical principles and methods to help in the understanding of
faith.
On the other hand, historically speaking, faith has helped phi­
losophy. For example, a man who believes what the Christian
revelation has to tell him about the nature of God cannot make
the philosophical error of thinking that God is an impersonal
force. Theology thus is a “negative norm” for philosophy,
inasmuch as a man's faith may warn him of errors he is making in
philosophy. It must be noted, however, that faith can tell a man
that he is making an error; it does not tell him why the error was
made or how to correct it—this is a properly philosophical task.
Secondly, there is a positive influence of faith on philosophy.
Faith suggests new problems to philosophical reflection (for ex­
ample, Christian thinkers go as deeply as they do into the nature
of personality’ because of the problems raised by the Incarnation
and the Trinity); and faith often presents truths that serve as
hints for the properly philosophical solutions of problems (for
example, St. Thomas’s statement, "Deus est ipsum esse” owes
much to the revelation of God’s name, “I am who am,” in Exod.
3:13).
Akin to this is the advantage that a Christian student has in the

[3]

INTRODUCTION

13

very learning of philosophy.11 Through his faith and the Christian
traditions, a Christian has accepted as certain and has become
familiar with truths like the dependence of the sensible universe
on God, the immortality' of his soul, and the existence of God and
other spiritual beings. He has a firm grasp of these truths, though
he may have only a slight understanding of them. Yet this much
at least he does understand, that reality includes much more than
is contained in the narrow limits of his own sense experience. Be­
cause of his firm acceptance of truths about nonsensible reality' he
does not find it hard to raise scientific questions about the nature
of the real or to follow a purely intellectual argument whose con­
clusions go beyond the limitations of immediate sense experience.
But what a Christian young man or woman accepts and can
understand with a measure of fullness, it may take an unbeliever
years of experience and study to grasp. Even with the best will
in the world, it is the hard work of years to arrive at a full under­
standing of being, of the existence of God as a nonmaterial and
unlimited being, and so forth. For this reason, Aristotle has said,
“Young men have no [intellectual] conviction about [the objects
and principles of wisdom], but only use the proper language”
(Ethics, Bk. VI, 1142al9).
But this by no means implies a formal dependence of phi­
losophy upon revelation and faith. Both the Christian and the
unbeliever philosophize in the light of rational evidence; both,
though with varying degrees of difficulty, can arrive at an in­
tellectual understanding of being and its principles and can
acquire rational convictions about them.
St. Thomas Aquinas has explained the relation between rea­
son and revelation very satisfactorily in the fourth chapter of the ¡/
first book of the Contra Gentiles, and a careful reading of this
fourth chapter will be most rewarding.
11 For a fuller development of this point, sec G. P. Klubertanz, S.J., “The
Teaching of Thomistic Metaphysics,” Gregorianum, XXXV (1954), 187-193,
202-205; E. Gilson, Thomas Aquinas and Our Colleagues (Princeton, Aqui­
nas Foundation, 1953), pp. 13-22.

14

CHAPTER I

[4-5]

4. Characteristics of organized, scientific knowledge

Not only is a scientific knowledge unified and organized by
having a complete set of similar data, by having a self-coherent
or internally consistent set of propositions in which these data are
expressed, and especially by having a single set of principles (in
some knowledges this is merely an ideal not yet realized) by
means of which everything in that field of knowledge is related,
but there must be an explicit showing of these relationships. A
man who has a scientific knowledge not only knows something,
but he knows that he knows. In other words, an organized knowl­
edge is in some sense a certain knowledge. From this point of
view, an organized knowledge contains not only data or facts but
also conclusions, which are arrived at by some form of reason­
ing or demonstration; hence, organized knowledge is properly a
demonstrative knowledge (scientia).
A second characteristic of organized or demonstrative knowl­
edge is that (with the exception of history), no demonstrative
knowledge deals with a singular thing as singular. Physics, for
example, is not interested in the individual peculiarities of this
falling body (for example, that it is a dark-green object falling at
11:03 A.M. in a second-story classroom in Idaho); similar ex­
amples can easily be found in the case of biology, chemistry, or
mathematics. (An exception might seem to be "individual psy­
chology,” but the individual is included in this science, not as this
individual—for example, John Smith—but in terms of the com­
mon characteristic of being an individual with an individualized
set of values or common variable traits.) In other words, organ­
ized, demonstrative knowledge is not of the individual and con­
sequently is not expressed through the use of proper names. Put
positively, demonstrative knowledge uses general or common
terms. Sometimes, also, an equivalently universal proposition is
expressed in the form of an indefinite particular (for example,
“A man is a rational animal”). We should not be misled by the

[ 4-5 ]

INTRODUCTION

15

grammatical form of propositions into thinking that some sci­
ences do not use universal or at least common terms. In the next
chapter we will examine the implications of universal knowledge
more fully.12
A third characteristic of every demonstrative knowledge is its
use of technical terminology. When a biologist is talking, the
word “cell” has a very definite meaning and usage quite different
from the meanings used by an electrician and a sociologist. For
ordinary usages, dictionary definitions are sufficient; but for the
specialized purposes of demonstrative knowledge, it is necessary
to have much more precise definitions or sometimes new defini­
tions not quite in harmony with ordinary usage. This situation
also occurs in the philosophy of being (for example, even the
term “being” needs a much more precise understanding in de­
monstrative knowledge than is necessary for everyday knowl­
edge), and consequently some definitions will have to be given in
accord with the specialized purposes of philosophy. At other
times it becomes useful to invent new terms. Thus for example,
the followers of Aristotle coined the term “metaphysics” (mean­
ing “beyond material nature”), as a technical term for the de­
monstrative knowledge of the real as such. We will use the term
“metaphysics” as a synonym for the philosophy of being as a
whole, as well as for the introductory part.

5. Thomistic philosophy
As we shall see much more fully in later chapters, there are
many ways of considering reality. Every grown person has an
outlook on life (sometimes called a Weltanschauung) that in­
volves an implicit metaphysics. Philosophers explicitly state and
develop their philosophical view of reality—and come to differing
conclusions. Some of these philosophers are wrong, as we shall
also try to see; but most often it_is_a question of how adequate a
philosophy is to express the totality of the real.
uSee below, secs. 11 and 18.

16

CHAPTER I

[5-6]

As beginners in philosophy, we are not yet in a position to
judge all the various philosophers. It is foolish not to try to make
use of the help we can get from a good philosopher, and it is
impossible to start out entirely without any metaphysics—a
normal eight-year-old is already developing an outlook on life.
But because our knowledge of reality as such is still on the every­
day level, it is likely to be mixed with much error. For practical
purposes, therefore, in order to get started in philosophy with
some hope of developing a reasonably good philosophy of our
own, we must take someone’s lead. What kind of criterion can we
use to pick a guide? (fl) He must know that he is building a
metaphysics; if he has only an implicit metaphysics, he will not
be of much help to us. For this reason, many thinkers who deal
explicitly only with specialized problems (for example, with logic
or ethics or theory of knowledge or philosophy of science) will
not be practical guides, (b) He must know the various kinds of
philosophies that have been constructed and have seen their
advantages and shortcomings through their historical develop­
ment. (c) His philosophy must violate no evidence; it must be
in harmony with all the evidence and certitudes that are avail­
able. These conditions are excellently fulfilled by St. Thomas
Aquinas.13 (Note that we are not going to take his philosophy as
true because he said it. To do this would be to acquire not a
philosophy but an opinion.)
This temporary procedure, however, should be replaced at
the end of our entire philosophy course by our own personal
understanding of the truth and adequacy of our philosophy. In
judging the adequacy of a philosophy, we must measure the
correctness and adequacy of definitions, principles, and conclu­
sions in relation to the proper object of the demonstrative knowl­
edge within which they function. To some extent we can be
doing this even as we go through the course, especially when
we have completed a unit.
“For a fuller discussion, sec below, secs. 106 and 109.

[ 5-6 ]

INTRODUCTION

17

6. Definitions14

The material object- of a knowledge dr- ¡'¿Dates indeterminately
and in its entirety the subject of a knowledge in relation to the
propositions that can be made about it. For example, the material
object of geometry is the lines, surfaces, solids, and angles (its
subject) in relation to what can be said about them.
'Hie formal object of a knowledge is the object precisely as
knowable, according to its manner of being known and its prin­
ciples. For example, the formal object of geometry is the con­
struction, measurement, and investigation of the properties and
relations, of its material object.
The proper object of a knowledge is the material object as
specified by the formal object. For example, the proper object of
geometry is the construction, measurement, and investigation of
the properties and relations of lines, surfaces, solids, and angles
in so far as these can be known and expressed in propositions.
Metaphysics is that demonstrative knowledge whose proper
object is the real as real.
Demonstrative (or scientific) knowledge is an exactly stated
knowledge with a single proper object, organized through selfcoherent definitions and, especially, by a single set of principles
and shown to be accurate and true by some kind of reasoning
process which leads to a certain assent or at least to a wellfounded assent. For example, physics, philosophy, geometry, and
history arc demonstrative knowledges.
Science is a kind of demonstrative knowledge concerned with
tin- observation of facts, the establishment of general laws, and
the explanation of these facts by means of general concepts
logically constructed and deductively verified. Only the natural
sciences arc sciences in this strict sense.
“This first set of definitions of terms is simply a vocabulary or glossary,
giving the meanings of these terms. These definitions settle no philosophical
problems; they only make it possible to talk about such problems. Italicized
terms are the ones that will be used most frequently and therefore ought to
be memorized.

18

CHAPTER I

[6-7]

Philosophy, descriptively speaking, is the collective name for
metaphysics, philosophy of nature, epistemology, and ethics
taken together.15 Philosophy is distinguished from other kinds of
demonstrative knowledge by its inclusiveness of all that pertains
to its subject and by its use of direct insights and ontological
concepts.
Thing is a whole or a complete individual (as opposed to
something that is merely a part, as for example, a hand; or to
a collection, as a heap of stones). For example, a tree, a dog, a
man.
Sensible thing is a thing capable of directly affecting our senses
and therefore something capable of being immediately perceived
in external experience. The three examples given of thing are also
sensible things.
Material thing is a thing among whose intrinsic properties are
(a) that it is capable of being measured and (b) that it is able
to undergo gradual change; it is not necessary that we be able
to sense it. (This is merely a descriptive definition; an essential
definition will be given later.) For example, the air 50 miles
above ground, a free electron, all sensible things.
Principle is that from which something else follows. For ex­
ample, the dawn is the principle of the day; fire is a principle of
heat; the structure of a watch is a principle of its movement.
A principle of being or reality is that from which or through
which something is or comes to be. For example, the principle of
a house is its builder and also the bricks and other materials that
make it up.
A principle of knowledge is some knowledge (usually a
judgment or a proposition, but not necessarily so) from which
some other knowledge follows, according to some kind of con­
nection between the two. For example, in a syllogism, the prem­
ises are the principles of the conclusion.
“ To define "philosophy” essentially is a very difficult task. Many so-called
definitions really define metaphysics; dictionary definitions are not of much
help. The second sentence of the above definition will not he understood by
the beginning student. It will be made clear in Chap. XIV.

[6-7]

INTRODUCTION

19

7. Readings
St. Thomas Aquinas, The Division and Methods of the Sciences:
Questions V and VI of St. Thomas’s Commentary on the De Trinitate
of Boethius (Toronto, Pontifical Institute of Mediaeval Studies, 1953),
q. 5, art. 4. This text deals with the relation between metaphysics
and natural theology.
E. F. Caldin, Science and Christian Apologetic, Aquinas Papers,
No. 17 (London, Blackfriars, 1951), pp. 1-12, on the method of sci­
ence. This is a simply written yet accurate presentation by a promi­
nent British layman.
Etienne Gilson, The Unity of Philosophical Experience (New York,
Scribner’s, 1940), pp. 299-320; ‘‘Historical Research and the Future
of Scholasticism,” The Modern Schoolman, XXIX (1951), 1-10; Rea­
son and Revelation in the Middle Ages (New York, Scribner’s, 1939),
pp. 67-84. The first of these selections deals with the distinctive
nature of philosophy, the second and third with the relation of faith
to reason. The author is an historian of philosophy as well as a
philosopher.
D. J. B. Hawkins, Approach to Philosophy (London, Sands, 1938),
pp. 1-22. Father Hawkins is a British philosopher.
Jacques Maritain, Degrees of Knowledge, trans. Bernard Wall and
Margot Adamson (New York, Scribner’s, 1938), Introduction. This
section concerns the place of metaphysics among various knowledges.
The author is a well-known philosopher.
John Wild, Realistic Philosophy (New York, Harper, 1948), In­
troduction and historical section. This passage deals with the relation
of philosophy to other forms of knowledge and shows the origin and
development of philosophy. Professor Wild is an American philoso­
pher; he follows Aristotle, though with some relation to St. Thomas
Aquinas.
Selected Passages from St. Thomas Aquinas

1. On the Nature of Metaphysics
As the Philosopher [Aristotle] teaches in his Politics, when some
things are ordered to one, one of them must be the regulating or
ruling one and the others the regulated or ruled. This is clear in the
union of soul and body, for the soul naturally commands and the
body obeys. This is the case also among the powers of the soul, for
the irascible and the concupiscible powers are in natural order ruled
by reason. Moreover, all the sciences and arts are ordered to one;
namely, to the perfection of man, which is his beatitude. For this
reason it is necessary that one among these sciences and arts be the
director of all the others, and this one rightly lays claim to the name

20

CHAPTER I

[ 7]

of wisdom. For it is the prerogative of the wise man to order (that is,
regulate, or dispose) others.
Which demonstrative knowledge this may be and with what it is
concerned can be judged if one diligently observes how someone is
fit to rule. For (as the Philosopher says in the aforementioned book)
just as men of remarkably superior understanding are naturally rulers
and lords, and men of robust body but wanting in understanding are
naturally servants, so the knowledge which is in the highest degree
intellectual ought to be regulative of others. And this [knowledge]
is the one which is concerned with the most intelligible objects.
Now we can take [the expression] “most intelligible objects" in
three ways. First from the order of the [act of] understanding. For the
things from which the intellect obtains certitude seem to be the more
intelligible. Hence, since the certitude of scientific knowledge is ac­
quired by the intellect through causes, the knowledge of causes
seems to be in the greatest degree intellectual.
Second, from the comparison of the intellect to the sense. For since
sense [knowledge] is the knowledge of particulars, the intellect would
seem to differ from sense by reason of the fact that it comprehends
universals. Hence, that demonstrative knowledge is in the highest
degree intellectual which deals with the most universal principles.
These are being and what follows upon being, such as one and
many, potency and act. But such principles should not remain entirely
undetermined, since without them there cannot be had a completed
knowledge of those principles which are proper to some genus or
species. Nor should these principles be dealt with again in some
one particular demonstrative knowledge, because, as they are requi­
site for the understanding of each and every kind of being, they would,
with equal reason, be dealt with in any particular knowledge. It re­
mains, therefore, that principles of this sort should be treated in one
common demonstrative knowledge, which, since it is in the highest
degree intellectual, is regulative of the others.
Third, from the intellect’s very knowledge. For since each and every
thing has intellective power from this, that it is without matter, it is
appropriate that those things be most intelligible which are in the
greatest degree separate from matter. For the intelligible and the
understanding must be proportionate and of the same genus, since
the understanding and the intelligible in act are one. But those things
are in the greatest degree separate from matter which not only
abstract from designated matter, “such as natural forms taken in the
universal, with which natural science deals,” but which altogether
abstract from sensible matter—and this not only according to their
intelligibilities (such as mathematical objects), but also according to
their act of existing, such as Cod and the intelligences. Wherefore
the demonstrative knowledge which considers these things appears to

[7]

INTRODUCTION

21

be in the highest degree intellectual and the chief and master of the
others.
Now, this threefold consideration ought to be applied to one
demonstrative knowledge, not to different ones. For the separated sub­
stances that have been mentioned [in the third place] are the universal
and first causes of being. It is, moreover, the work of the same
knowledge to consider the proper causes of a given genus and the
genus itself; thus, natural science considers the principles of natural
body. Hence, it is proper that one and the same knowledge have as its
function to consider separate substances and being in common, which
is the "genus" of which the substances mentioned arc the common and
universal causes.
From this it is clear that, although this demonstrative knowledge
considers the three classes of objects spoken of [common principles,
universal causes, separate substances], it does not have any one of
them at all for its subject, but only being in common. For that is the
subject of a knowledge of which we seek tlie causes and passions
[properties]; but the causes themselves of a given genus are not the
subject. For the knowledge of the causes of some genus is the end
to which the consideration of a knowledge finally attains. Still, though
the subject of this knowledge is being in common, the whole of it is
said to be about those things which are separate from matter according
to their act of existing and according to their intelligibility. For not
only are those things which can never be in matter said to be separate
from matter according to their esse and their intelligibility (such are
God and intellectual substances), but also those things which are able
to be without matter, such as being in common. But this could not be,
if [the latter] depended on matter for their existence.
According to these three classes of objects which have been men­
tioned, therefore, from which wc weigh the perfection of this demon­
strative knowledge, it comes to have three names. It is called divine
knowledge, or theology, insofar as it considers the aljove-mentioned
substances. It is called metaphysics, insofar as it considers being and
those things which follow upon it; for these transphysical things are
arrived at by the way of analysis, as the more common are arrived
at after the less common. It is spoken of as first philosophy, insofar as
it considers the first causes of things. Thus it is clear what the sub­
ject of this demonstrative knowledge is, in what way it is related to
other knowledges, and by what name it is named.
Commentary on Aristotle’s
Metaphysics, proemium.

2. Metaphysics and Other Knowledges
In all the sciences and arts, whether speculative or operative, it is
proper that what is higher and what orders others should consider

22

CHAPTER I

[7]

[the] more universal intelligibilities, since principles are few in
number and very great in power, and those that are simple are ex­
tended to the most objects. For example, military science is subject to
political science, and cavalry science is subject to military, and so on
successively. Political science is subject to the consideration of human
good, simply. But military science considers this same good inasmuch
as it is determined to matters of war, and so on. Because of this the
lower takes its principles from the higher, and this is a kind of propter
quid [causal] proof. This relation is more indisputably evident in the
speculative knowledges, because metaphysics, which orders the other
knowledges, considers the intelligibility of being absolutely, while the
other sciences consider being according to some determination.
Commentary on the Second
Book of the Sentences, dis.
3, q. 3, art. 2.
Habits are specified by their objects according to that intelligibility
to which they principally attend. . . . Even though something is com­
mon, there is a particular and proper intelligibility of object. Thus, first
philosophy is a special demonstrative knowledge, though it considers
being inasmuch as it is common to all things, because it considers that
special intelligibility of being inasmuch as it does not depend on matter
and motion.
Commentary on the Third
Book of the Sentences, dis. 27,
q. 2, art. 4, qa. 2.

Metaphysics . . . considers all things inasmuch as they are beings,
not coming down to a proper knowledge of morality or nature. For
the intelligibility, “being,” since it is different in different things, is
not sufficient for the specific knowledge of things.
Commentary on the First
Book of the Sentences, pro­
logue, q. 1, art. 2.
3. The Certitude of Metaphysics
The more a scientific knowledge is prior in nature, the more certain
it is. This can be seen in that those sciences whose object can be
said to be an addition to that of other sciences arc less certain than
the sciences which take fewer things into consideration. For example,
arithmetic is more certain than geometry, for the objects of geometry
have something more than those of arithmetic. This is clear if we
look at what each of these sciences takes as its first principle; namely,
the unit and the point. For the point adds location to the unit. For

[7]

INTRODUCTION

23

the intelligibility of the unit is constituted by undivided being. This
notion, when it is taken as a measure, is the principle of number. But
the point adds location to this.
The particular sciences are posterior in nature to the universal sci­
ences, because the subject of the former adds to the subject of the
latter. For example, “being as changeable,” with which the scientific
knowledge of nature deals, adds to “being (without qualification)”
which is the subject of metaphysics and adds to "quantified being"
which is the subject of mathematics. Therefore that scientific knowl­
edge which is about being and the most universal objects is the most
certain. Nor is it to be objected that metaphysics is here said to be
about fewer things, though it was said above [earlier in the same sec­
tion, not quoted here] that it knows all things. For the universal
comprehends fewer things in act, but more in potency. And a science
is the more certain the fewer actual considerations are necessary for
the consideration of its subject. Wherefore, practical sciences are the
most uncertain, because they must consider the many circumstances of
singular operables.
Commentary on Aristotle’s
Metaphysics, Bk. I, lect. 2
(ed. Cathala, No. 47).

CHAPTER II

The Meaning of "Being”
8. Various senses of the word real

We have seen that metaphysics can be described briefly as the
demonstrative (scientific) knowledge of the real inasmuch as it is
real, and that therefore its basic question is, “What is it to be
real?” Before we can go further into this question, we must dis­
tinguish the various senses of the word “real.”
In the proper sense of the word, a real being is an actual being,
one which is not merely an object of the mind or merely possible,
but is actually in itself. This preliminary description will be made
more exact later on. The best way to clarify the proper meaning
of real is by contrast: an existing airplane is a real machine, a
spaceship is not real (not in 1955 at least); Citation is a real
horse, Pegasus is not; Sir Winston Churchill is a real human
being, Ichabod Crane is not; angels are real beings, leprechauns
are not; an orange is a real being, a perfect sphere is only an ob­
ject of thought.
Sometimes the word “real” is used in an extended sense, for
example, in logic and epistemology, to designate not only what
is actually now but also whatever has existed, will exist, or can
exist independently of thought. In this extended sense, a dinosaur
is a real animal, but a centaur is not; Hamlet is a real character,
Pogo is not; the battles of the Creeks and Trojans were real, the
quarrels of Jupiter and Juno were not. 'Ibis extended meaning of
real is used to make a distinction among objects of thought: real
24

[8-9]

THE MEANING OF “BEING”

25

objects are those that actually exist or could exist; unreal objects
are those that cannot exist.1
Henceforward, real (and forms derived from it) will be used
only in its proper sense; that is, to designate the actual things
which are now. Thus, when we speak of ’’knowledge of the real”
we will mean “knowledge of things which are here and now
actual,” and when we speak of “the real order,” we will mean
“the order (or totality) of things which are actual here and now.”
If we want to use the extended sense of the word “real,” we will
always attach the qualification, “in the wide sense.”

9. The question: “What is it to be real?”
Since metaphysics is the demonstrative knowledge of the real
inasmuch as it is real, and since we can know and talk about
things that are not real, obviously our first question must be,
What is it to be real? The question, “What is it to be a real
’ For example, a man can think about a dog he used to own which died
last year; the dog is no longer part of the real world in which he lives today.
A man can think of a purely fictional character; again, no actual, properly
real being corresponds to his thought. But the one who thinks about these
things can recognize that in the case of the dog there teas an actual real
thing to which, if it were now, his thought would conform; he can likewise
recognize that in the case of the purely fictional character diere could be an
actual thing to which, if it were actual, his thought would also conform. In
both cases, absolutely speaking, there is no actual real thing of which he is
thinking; in both cases there is simply no-thing in the real order. Neverthe­
less, the word ‘’real" has been extended to designate objects of thought
such as these in order to mark off a distinction between them and still other
objects of thought to which no real thing can correspond: for example, the
internally inconsistent objects mentioned in die earlier paragraphs of this
section (leprechauns, centaurs, Pogo, the world of Greek mythology) or
such objects as necessarily involve purely mental objectivity, such as logical
genera and species ("the species, man”; "the genus, animal”). A diagram
may help to show the relationships of these terms:
real in die wide sense.......... •
as opposed to
the mere object of thought

the properly real, the actual
as opposed to
the past, the future, the possible

For a further explanation of this, see below, sec. 74.

26

CHAPTER II

[9]

thing?” is not a question about our knowledge2 but about the
thing known.
To help ourselves see the meaning of this question and the
basic importance of the answer, we will look at some historical
answers before we look at reality itself.3 Our purpose is to under­
stand these philosophical positions, not to refute them.4
(A) A first answer to the question is: A thing is real because,
and inasmuch as, it acts or does something. A philosophy which
answers the question of the meaning of reality in this way is
called "phenomenalism" (from the Greek word meaning "appear­
ance”). Phenomenalism, or "actualism,” does not mean, “Every
real thing acts in some way” or “We know that something is real
because we find it acting” or “We can tell what kind of thing
something is by seeing what sort of actions it performs.” These
• Questions about our knowledge of the real are questions like, “How do
we know real things?” and, “How can we tell, from looking at our knowl­
edge, whether an object of knowledge is real or not?” These questions can­
not be answered or even considered now, for the answers to them depend at
least in part on the philosophy of human nature.
8 To make these different answers more concrete, we will refer to various
historical positions. We are, however, not studying the history of philoso­
phy, and so we are not bound to an adequate exposition of the thought of
the great philosophers or to a refutation of their systems as wholes. We are
interested only in clarifying the question and seeing what is involved in it.
If a reader should desire further information on some of these basic
positions, he can find a full introduction and a guide to further reading in
the following books. James Collins, A History of Modem European Philoso­
phy (Milwaukee, Bruce, 1954), pp. 109-117 (on Hobbes and materialism);
pp. 204-207, 226-228 (on Spinoza and the relation between reason and
reality); pp. 267-277, 279-281 (Leibniz and the world of intelligible es­
sence); pp. 707-710 (on Comte and positivism); pp. 408-409, 415, 433-436
(on Hume and phenomenalism); pp. 509-512 (on Kant and the possibility
of metaphysics; a higltly recommended section). Etienne Gilson, Being and
Some Philosophers, 2d ed. (Toronto, Pontifical Institute of Mediaeval Stud­
ies, 1952), pp. 83-96 (on Scotism and the particular); pp. 51-73 (On Aver­
roës); pp. 74-82 (on Avicenna, another kind of essentialist).
4 It is unfair to attack something which a person does not understand.
Moreover, instead of refuting the position, one is likely to miss the point en­
tirely. So the first requisite is to understand both our own position and those
of the philosophers who hold different positions. And once we have a thor­
ough understanding both of our own philosophy and of other philosophies in
their historical context, it is usually unnecessary to engage in a refutation of
them. To some this proposition may seem a paradox; the only answer is a
real study of the history of philosophy.

[9]

THE MEANING OF “BEING”

27

three propositions are perfectly true, but they are not the basic
statement of actualism. Actualism holds that action is the reality
of the tiling. According to this doctrine, for example, “I” am real,
in the sense that there are some thoughts, desires, movements,
and so forth, which in some inexplicable way belong together.
The sources of this doctrine are an incorrect understanding of
substance and accident and a misuse of the ability of our mind to
consider an action without considering the agent and thus to
consider the action as if it were a thing?
To assess the value of phenomenalism we need only to con­
sider attentively the whole real things which are actual. How
does an actual real thing manifest itself to us in our experience;
for example, a human person? A human person manifests himself
to us as something real which acts; a person can act precisely
because he is real. A thing is not real in consequence of its action;
rather, it can act because it is real. We will have to investigate
the relation between a being and its action later on,c but for the
time being it is sufficiently clear that acting is not the very mean­
ing of being real.
( fí ) A second answer to the question, What is it to be real? is
the answer given by materialism. For example, what is the dif­
ference between an architect’s idea of a house and the real house
which is the result of the plan? It is that the plan has been
“realized" in the material components of lumber, cement, stone,
clay, and so forth. According to this explanation, an intelligible
plan, order, or structure can be real or not real, and matter is the
principle of reality. Materialism takes an explanation which is
superficially sufficient for the explanation of artifacts and un­
justifiably applies it to the ultimate explanation of reality.
Materialism can take several forms. Many materialists think of
principle or source of reality in all things. Others, trying to bring
philosophy more into line with what they consider are scientific
ultimate reality as a collection of material particles which are the
8 See below, secs. 30, 82, 88, 93, 94.
8 See below, secs. 30 and 94.

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CHAPTER II

[9]

views, think of ultimate reality as a large amount of “free energy”
which can be either structured into things or left “free,” “un­
attached” (for example, in the form of radiation).
Materialism involves a number of consequences which we are
not going to take up here, but which it will be useful to point
out. It involves (a) the denial of any spiritual reality or person;
(b) at least logically, the denial of any essential differences in
the activities of things; (c) the explanation of life and conscious­
ness in terms of the nonliving and the nonconscious. The first of
these consequences is evident. The second follows from the ad­
mission by the materialist that matter is an undifferentiated
principle. Differences can therefore be only accidental. Those
materialists who hold that consciousness, desire, and so forth, are
really different from nonconscious activities do so at the cost of
logical consistency. For—and this is the third consequence—if
matter is the principle of reality, then real activities are material,
and the activities of nonliving things are the constituent elements
of all activity'. It is fine rhetoric but poor logic to insist that
materialism fully respects the evidence of life and knowledge.
For the moment, we are going to consider only' one point: the
meaning of real as given by materialism, “To be real is to be
material or in matter.” It is true that the things which we experi­
ence arc material. Why should we even question the identifica­
tion of reality with matter? We question it for the simple reason
that we have equally immediate experience of our own conscious
activity, especially that of intellectual knowledge and of choice.
These activities have as much claim to be called real as any
activities of the tilings we find that are distinct from us. If we
wish to respect the evidence, we must admit that both the activi­
ties of physical things and our own conscious activities are truly
real. If we look attentively at our own acts of knowledge, they do
not present themselves as sensible. They have no directly dis­
coverable relation as actions to any material characteristic.
Intellectual understanding has no sensible qualities; it presents
itself as simply different from, and not describable in terms of,

[9]

THE MEANING OF “BEING”

29

mass and motion, chemical action, electromagnetic activity, or in
one phrase, any activities o£ nonhuman things. Take the act of
understanding what a square is (or what justice is or that a given
syllogism is valid). Examine that act. It is real; you do under­
stand. Yet that act remains indescribable except in its own super­
sensible terms.
Hence, it is good to ask: “Is matter identically reality?” “Is
matter the principle of reality in all real things?”7
Matter, as the materialists talk about it, is not something which
we can experience. Matter is “in itself’ always determinante. It
becomes this or that, it acquires this or that structure. Real matter
is always some kind of matter. As far as direct sense experience
is concerned, we experience minerals, plants, animals, men, air,
the planets, and so forth. But the determinability of “matter in
itself’ is more strikingly seen in the case of the supposedly ulti­
mate particles or energy: these ultimate particles have definite
electrical characteristics and a definite size;8 energy is always of
some definite kind and quantity; a particle is always an electron
or a proton or some other kind of particle (or “wave packet” or
whatever other term scientists may find better). In other words,
the “matter in itself,” which is alleged to be the principle of
reality, is itself a determinable genus that is determined by some
other principle.
’ The first of these two questions implies the position of extreme material­
ism, which holds that only matter exists, so that matter is reality and all
reality is matter. The second implies the position of a group of materialists
who call themselves “modern materialists” and of dialectical materialists
(Marxists); these materialists admit some realities—for example, ideas—
which are not identical with matter but arise from matter, depend absolutely
on matter, are real when they are in matter, and have no real effects on
matter.
8 At the present time (1954), physicists hold that the electron (and other
subatomic particles as well ) does not have a completely determined size and
position. Without going into an explanation of the nature of scientific theory
(see Chap. XIV, sec. 100), this much at least is clear: subatomic particles
have a definite quantum and kind of energy; their size is not completely
indefinite but can be known within some limits; their location cannot be
determined at the same time as their velocity, but it also is not completely
indefinite.

30

CHAPTER U

[9]

But to be real is to be fully determinate. Why? Because to be
determinabZe has a double implication: (1) to be able to be
something or other and (2) at the present moment not to be it.
We must then ask the question, Docs it make sense to say, “That
is virtue of which a real thing is determinable, and consequently
not yet a definite reality, is simultaneously that in virtue of
which every real thing is real”? Recall again the precise point of
the present discussion. It is not to determine whether there is or
is not an individual existing thing which is purely spiritual
(without any matter at all); it is simply this, Is a real thing
(material or not, as the case may be) real in virtue of some in­
determinate “matter in itself”? In other words, Is there something
even about a material thing which is not merely “matter in itself”?
(C) A third solution offered to the question, “What is it to be
real?” is not quite so simple and naive as the first. In general, it
consists in saying, “For a thing to be real is to be the kind of thing
it is.” For example, to be a real chair is simply to be a chair; to be
a real dog is simply to be a dog. In formal and general terms, this
doctrine can be summed up by saying, “To be real is to be an
essence (quiddity).” We will label this type of explanation
“essentialism.” Historically, essentialism has taken four major
forms?
(1) Platonic essentialism ascribes full reality to the “essence
in itself”—for example, to the “horse in itself,” “man in himself,”
“good in itself,” and so on. These essences in themselves are the
fully real things, but they are not immediately experienced. On
the other hand, the things we immediately experience are real
by sharing (participating) in the fully real tilings. Consequently,
the principle of reality in the things we experience is that which
is fully real in itself by being what it is. The essences in them* Many more divisions could be given, but our present purpose is suffi­
ciently served by a consideration of these types. It is important to note that
not every essentialism is realistic; in fact, many types of essentialism are
purely idealistic; that is, they maintain that reality consists only of ideas.
It will be interesting to recall this observation when we make our critique of
essentialism.

[9]

THE MEANING OF “BEING”

31

selves are also called “separated forms” or “ideas.” But this
Platonic explanation replaces a question with a puzzle, for what
is asserted is that the reality of x lies in its relation to y which is
in itself and also somehow in x. What is this relation? How can
the idea be both separated from particulars ( in order to be real,
in other words, to be a pure essence) and united to them (in
order to give reality to them)?
(2) Because this relationship is essentially ambiguous and
obscure many modern Platonists have abandoned the separation
of the ideas and maintain that an individual or a real thing is
constituted by the combination or intersection of many universals
(for example, Peter is that particular thing constituted by the
coming together of man, white, tall, slender, curly-haired, and so
forth). But this theory has two defects: although a collection of
universals may be less common than any single universal, it is
still not really an individual (and we certainly have direct ex­
perience of individuals, ourselves for example); secondly, there
is no effective way to distinguish between a real thing in the
proper sense of the word and an essence or a possible thing
(which is real only in the wide sense of the word). The Lone
Ranger can be more fully described by many persons than Julius
Caesar; yet the first is a fictional character and the second was
real.
•
(3) The most subtle of the essentialist explanations is the
Scotistic. According to the followers of Scotus, there are various
kinds or degrees of reality (the proper meaning of “reality” is
not directly admitted by them). The minimal degree of reality' is
that of an object of thought; the next, that of an essence; the
highest is that of an essence with haecceity (that is, the ulti­
mately actual singularizing principle). For example, “man” is
real with the reality of essence; “Peter” is fully real, having the
reality both of essence and of singularity (in other words, he is
“this man”). Now, it is true that the properly real is the singular
(as we shall see later), and Scotism alone of the essentialist sys­
tems has seen the importance of preserving the singularity' of

32

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[9]

things, but it has done it at some cost to the unity of the thing.
And finally, if singularity makes the properly real, and if we can
have fully determinate singulars among the objects of the mind,
then even in this system we have no unambiguous answer to the
question, ‘ What is it to be real?”
(4) There is another way of understanding the statement, “A
thing is real because it is what it is.” This way differs from all
Platonic systems in interpreting differently what a thing is. For
the sake of convenience, we shall attach this theory to the name
of Averroës.10 According to the Averroistic theory, an essence is
composed of two principles: matter (the potential principle of
essential change) and form (the actualizing principle of specific
determination). Neither matter nor form is real of itself; only the
composite is real. This theory is not a materialism, for it holds
that matter is only the potential principle of essence that indi­
vidualizes the essence and so in the thing is the reason why it is
this thing. Nor is the theory a simple essentialism, for form is not
real of itself, but is the actualizing and specifying principle,
which in the thing is the reason why it is this kind of thing. The
Averroistic theory explains how material things are in different
species and are capable of essential change. It does not answer
the question, "What is it to be real?” and Averroës explicitly says
that this is not even a good question.11 Why is this so? As far as
nonmaterial things are concerned, he says that they arc actual by
being what they are; and in this answer he shows himself to be
at bottom an essentialist, with all the difficulties of essentialism.
The basic difficulty of essentialism, as wc recall, is that it provides
no criterion of distinguishing between a properly real thing and
a thing that is real only in the wide sense. Averroës does try
to provide such a criterion. Material things, for him, are such as
are generated, that is, caused in time from pre-existing things.
* For further information on Averroës, see the bibliographical references
in n. 3.
u In his Destructio Destructionum, disp. 5.

[9]

THE MEANING OF “BEING”

33

This, of course, is true with regard to the things of our present
sense experience, but it is not to the point. When we ask, “What
does it mean to be real?” we are not asking about the efficient
causes which produced the real thing. True, we understand some­
thing about the kind of reality a thing has when we know that
it is not perpetual but has a temporal dimension. But to know
that there arc different kinds of reality still is not the same as
knowing what it means to be real. Hence, any philosopher who
says, “To be real is to have been caused,” no matter how many
valuable things he may have to tell us on other points, has
missed the precise bearing of the question.
All die essentialists agree in this one point: to be real is to be
what something is. It is perfectly true that of all the things of our
experience, the question, “What is it?” can be asked. But when
we answer the question, we still do not know whether it is or not.
No matter how complicated the answer to the question, “What
is it?,” we still do not know whether the thing is or not. “Is it?”
cannot be answered by telling what it is. For example, whether
I say very vaguely, “I am thinking of something,” or very con­
cretely, “I am thinking of Queen Elizabeth’s older brother,” I
cannot judge whether these objects are properly real or not by
the extent to which they are determinate. In other words, I do not
know, from even the most complete formal determination,
whether I am thinking of something real in the proper sense of
the word. And since our original question was, "What does it
mean to be real, in the proper sense of that word?” we sec that
it is still unanswered.
In summary, then, these are the inadequate answers to the
question we have considered: to be real is to perform some
action, to be material, to be or to have an essence (whether this
essence be universal or singular, whether it simply is or whether
it is caused). All these things are true about the tilings of our
experience, but they fail to consider the real as real. We must
look somewhere else for our answer.

34

CHAPTER II

[ 10 ]

10. The Thomistic answer to the question: “What is it to be
real?”
To discover what it is to be real, we need to look again at some
real thing in tlie light of our previous discussion,12 and we must
begin with the only real things that we directly experience; namely,
with singular things that are material and sensible. And we must
consider some really existing thing immediately present to us
( not merely some words designating a singular which is not now
experienced as real). Let us take ourselves or some person im­
mediately present to us. This person is performing actions by
which we become aware of him; even in our own case, our aware­
ness of ourselves arises from something we do or undergo. A
person is material or sensible. A person is some kind of thing; he
has a human nature and not some other kind of nature. These
propositions are true (and the evidence for them is precisely the
acting material thing which is a human person). But are they
what we mean when we say, “I am,” “He is”? Our being expresses
itself in action; it is limited by materiality and by the nature we
have; yet when we reflect on our own awareness of ourselves,
each one of us sees immediately in his own highly personal ex­
perience: I am not simply any one of my actions (much less a
collection of or sequence of actions). I am material, but that I
am is not what I mean by materiality or vice versa. The same
evidence will appear if we attentively consider another person.
Furthermore, the fact that to be is not identical with any nature
is evident from the consideration that quite different natures all
are. Each kind of thing is in its own way, of course, but neverthe­
less it truly and really is. To be is what is basically meant by
“being rear or a "being.”
An indirect reflection may clarify this proper meaning of
“The discussion of three basic philosophical positions in the preceding
section was not a proof or even a full philosophical refutation of them. The
discussion was intended to clarify the meaning of the question about the
real and to direct our attention to tlie various factors which ought to be
considered.

[ 10 ]

THE MEANING OF “BEING”

35

“real.” Suppose we compare a real human person here and now
present in our experience with one of Shakespeare’s characters,
for example, with Falstaff. Both the real person and Falstaff are
singular or individual; both have an intelligible essence—and
even the same intelligible essence, that of humanity; both have
the sensible qualities by which we know matter; both have par­
ticular words and actions of their own. Yet there is all the dif­
ference in the world between them: one is real; tlie other is an
object of thought. And the most basic statement that we can
make about them is that the real person is, exists, whereas the
fictional character is not, does not have its own proper act of
existing.
Hence, from the fact that the properly real is that which is, we
get its proper technical name. The verb is has as its infinitive to
be, and as its corresponding verbal noun, being. Hence, being
in its first sense means “that which is” or “something having an
act of existing." 18 For the phrase “act of existing” we will some­
times use the noun “esse"; for example, we might define “being”
as “something having esse.”
Since the properly real is that which is, and since metaphysics
is the demonstrative knowledge of the real as real, we can express
the object of metaphysics fully and accurately by the phrase
“being as being,” or in the fuller form, “whatever has an act of
existing (esse) inasmuch as it is." That is why we call meta­
physics the “philosophy of being.” 11
Before we can proceed further in our investigation of being,
however, we need to reflect carefully on our knowledge of
being.111
“The term “something” means “an individual object, known and ex­
pressed in an indeterminate, unspecified way.” A real thing can be called
“something”; so can fictional and mathematical objects. Hence, we can say
technically, something directly signifies an indeterminately known essence
and usually connotes existence. See above, sec. 6, on the definition ol “thing”
and below, secs. 12(a) and 72.
“ This point is treated in Selected Passages, No. 4.
“See also below, sec. 19; the treatment of our knowledge of the being
even of sensible tilings will not be completed until sec. 34.

36

CHAPTER II

[ 11 ]

11. Demonstrative knowledge and abstraction

To have a full understanding of being, it is necessary to reflect
on how we know it. But first it will lx? necessary to consider other
demonstrative knowledge with which we arc more familiar in
order to see similarities and differences. Knowledge, of course, is
not a thing in itself. As an act, it is the act of a man who knows
by his senses or his intellect or both; as a habit, it is a qualify
of a man. (Here we simply accept the fact that sense and in­
tellect are different; in the philosophy of human nature these
powers are considered in detail, and the kind of difference be­
tween them is proved.)10 The knowing subject is a man, not an
intellect or a sense. It is by a figure of speech that we say, “The
senses know this,” and “The intellect knows that.” It is, however,
a convenient, shorthand way of speaking, and we shall often use
it.
We have already seen that no demonstrative (scientific)
knowledge concerns the singular as singular, in other words, that
demonstrative knowledge is common or general in character.17
We should be careful not to assume from the start that all sci­
entific knowledge is general in exactly the same way.18 Most
demonstrative knowledges are universal, in the sense that they
employ univocal concepts and terms.’1* Univocal concepts deal
with one characteristic of things that is common to many and
leave differences out of consideration. Univocal concepts are de­
rived, either immediately or mediately, by abstraction from
By spontaneous knowledge we know that intellect and sense are differ­
ent. For a philosophical examination of the nature of the difference and a
proof that intellect and sense are essentially different, see G. P. Klubertanz,
S.J., Philosophy of Human Nature (New York, Appleton-Century-Crofts,
Inc., 1953), pp. 158-164.
w See above, sec. 4.
“The kind of generality which metaphysical knowledge has will be ex­
amined in Chap. HI.
'* A univocal term, as we know from logic, is one that is applied in exactly
the same sense to many individual things, for example, “gold,” “frog,”
“chair.” Sec below, sec. 18.

[ 11 ]

THE MEANING OF “BEING*’

37

material tilings.20 When, in the understanding of a material thing,
we consider one characteristic, trait, or aspect of it and omit
others, wc are said to “abstract” from the latter. The two simplest
kinds of abstraction are called “total” and “formal."
The verj7 name, “total abstraction,” is a kind of misnomer, but
it is traditional and has a certain value. Suppose we consider the
existing individual or being as fully determinate (for example,
Peter) and then drop out of consideration the individual deter­
minations and limitations; the result is an abstract consideration
of the whole being indeterminately. When I look at a particular
pencil, a particular piece of paper, a particular human being and
know them as pencil, paper, and man, I have performed an act of
total abstraction (“total,” because each of these nouns designates
a whole and entire thing [not merely a part]; “abstraction,” be­
cause the definite individual characteristics are omitted from
consideration). Total abstraction can be carried further than this;
that is, the being can be known more indeterminately, according
to a more and more ultimate genus. For example, Peter can be
known not only as man but as animal or living thing. The limit
of this kind of abstraction is “material substance”;21 this is the
matter with which some physical sciences deal. Total abstraction
is sometimes called the “first degree of abstraction.”
“Formal abstraction” is almost a reverse type of abstraction. In
this second type, a formal determinant is considered apart from,
and independently of, others. A ver}' clear example is found in
the knowledge of number, figure, and surface, which can be con* There are various ways in which univocal concepts arise. Those derived
immediately from sensible things arc gained by simple abstraction. Other
univocal concepts are made by combinations of the first kind, by secondlevel abstraction (see n. 22), and by mental construction (see sees. 100 and
107). For the relation of such concepts to real things, see below, sec. 74.
” If we attempt to cany total abstraction further, we no longer have
knowledge of a real thing; perhaps we come to a being of reason, “no-thing
conceived of as the indeterminate possibility of being” (cf. sec. 74, on beings
of reason). It is true that we can understand "substance’ without under­
standing it as material, but this is done, not by way of abstraction but by
way of separation; see below, sec. 12(b).

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CHAPTER II

[ 11-12 ]

sidered by the intellect apart from the sensible qualities with
which they are associated in the real order. This kind of abstrac­
tion consists in considering an accidental form (or a perfection
considered after the manner of an accidental form—see Chapters
XII and XIII ) apart from the other perfections of a being, pro­
vided that this accidental form does not depend upon these
other perfections for its intelligibility. “Formal abstraction” is
often called the “second degree of abstraction”; it is connected
with such operations as counting and measuring.
In general, abstraction22 in its proper sense is an act of sim­
ple and absolute consideration, which consists in apprehending
one characteristic or intelligibility (ratio) without another with
which it is associated in the real order. Now, we learn in logic
that an act of absolute consideration belongs to the first act of the
mind, the simple apprehension. We also know from logic that the
object of simple apprehension is an essence or quiddity.
In summary, a consideration of most scientific knowledge
yields these general conclusions. Most scientific knowledges deal
with strictly universal and univocal concepts. Such concepts are
the result of at least total abstraction; formal abstraction may
also be involved, as well as other types of abstraction. In any
abstraction something is always omitted from the object, and an
abstraction, in the strict sense, is an act of simple apprehension
directed to an absolute consideration of an essence. Is Meta­
physics like other scientific knowledges? Is its object abstract or
not?
" In addition to these two basic types of abstraction, there are other, more
complicated types of abstraction, that for convenience’ sake we will call
“second-level" abstraction. Whereas both total and formal abstractions have
their point of departure in the real tiling, a second-level abstraction has its
point of departure in a previous knowledge; for example, “humanity,” which
is the intelligible form (intelligibility) of man, arises by second-level ab­
straction from "man,” which is itself a product of total abstraction. Secondlevel abstractions are more properly called constructions than abstractions,
but there is some similarity, in that the products of second-level abstraction
also contain less than the initial stage from which they are derived.

[11-12]

THE MEANING OF “BEING”

39

12. Our knowledge of being as being

We must approach the problem of our knowledge of the object
of metaphysics in two stages, for there are two knowledges of
being—the primitive notion of being (which St. Thomas men­
tions as ens primum cognitum), and the being which is the ob­
ject of metaphysics, namely, being as being.
A. THE PRIMITIVE NOTION OF BEING

Do we reach being by abstraction?28 First of all, abstraction,
even total abstraction, always leaves some part of our initial real­
ity out of consideration. Now, if we were to say that “being” is
reached by abstraction from a real being, we would imply that
there is in the real thing some not-being, which is left out of con­
sideration; but since not-being is nothing, nothing can be left out
of consideration. Secondly, abstraction pertains to the first opera­
tion of the mind (simple apprehension) and so concerns only
essences.24 But being is “some definite individual which is,” and
” The subsequent discussion is a straightforward phenomenological analy­
sis of experience. For those who approach this problem with preconceptions
(philosophical or otherwise), the following points may be made, (a) The
human intellect (not just the human knower) does know singulars. (See
G. P. Klubertanz, S.J., "St. Thomas and the Knowledge of the Singular.” The
New Scholasticism, XXVI [1952], 135-166). (b) The doctrine of the three
degrees of abstraction is not a complete analysis of all knowledge, but only
of scientific knowledge; it ignores perceptual knowledge, (c) The meta­
physician, the philosophical psychologist, mid the epistemologist will see that
the “commonness” of metaphysical conceptions, principles, and propositions
is not arrived at by abstraction (properly so called) but by separation and
related processes. The logician (who ignores processes and meanings and
considers only terms) calls all nonsingular terms abstract and measures their
“distance" from sensation in terms of degrees. Hence, since metaphysics can
conclude to beings which cannot be sensed at all, the logician will consider
it the “most abstract” of all sciences, in the “third degree of abstraction.”
For a person to insist on doing metaphysics as if it were logic is to doom the
whole metaphysical enterprise to ruin from tire start.
* By the term “essence” we mean that which we name, describe, or define
(that is, as what it is). The term "quiddity” is an unfamiliar term for “es­
sence." The statement in the text is not meant to imply that all the objects
of apprehension are simple concepts; there are some very complicated ob­
jects which we will consider below briefly in sec. 74.

40

CHAPTER II

[ 12 ]

so to be, to have an act of existing, is other than and different
from the “definite essence" in the being (the “definite individual
which is”). Hence, the act of existing cannot be brought into a
concept by any type of abstraction properly so called. And if the
act of existing is not included in being in some way, then we do
not have being. Hence, for both of the reasons advanced above,
being cannot be reached by abstraction. In other words, the
knowledge of being is not a simple concept (apprehension) of
an essence.
There are, however, other forms of intellectual knowledge,
namely, judgment and reasoning. Judgment is that act of the
mind by which we assert (or deny) that something is, or is
modified in some way or other. Judgment, therefore, directly
reaches the esse of a thing. In other words, in a judgment we
know that a thing is. The judgment, it is true, virtually25 contains
an apprehension of an essence. We cannot assert “is” without at
least implicitly understanding something (“this,” “it,” and so on).
But what is special and peculiar to the judgment is that a direct
perceptual judgment is the knowledge that some existent is.
The things that we directly and immediately assert to exist arc
the sensible things of our experience, and the judgments that we
make about immediately experienced things are called percep­
tual judgments. The act of existing thus attained is the esse of a
material, singular thing.
When we have experienced at least two sensible things and
judged that "This is” and “That is,” we can reflect and sec that
neither “this” nor "that” is simply identical with “is,” even though
each one of the subjects is a singular subject. When we see that
“is” is not proper and peculiar to either “this thing” or “that
thing,” we discover a common intelligibility, “Something is.”
When we go from “This is” and “That is” to “Something is,”
we disengage the latter intelligibility from its original presenta“'Thc term “virtually” means here: “docs not actually contain an appre­
hension as a distinct act but has a function equivalent to that of an appre­
hension.”

[ 12 ]

TIIE MEANING OF “BEING*’

41

tion in the completely singular sensible tiling. But we do not do
tins by any kind of abstraction, for we leave nothing out. The
“something” in the judgment “Something is” expresses indefinitely
a completely determined, singular thing (not a general essence).
This nonabstractive movement from a particular judgment or
judgments to a common judgment wherein the singularity is im­
plicit (that is, not explicitly known and stated), we will call the
“judgment of implicitation.” 26 The “commonness" of the “some­
thing” in the judgment “Something is” is not that of an abstract
universal, but rather that of a particular with an indefinite refer­
ence to singulars (Peter, Prince, this chair).
From the judgment "Something is” we can form a complex ap­
prehension27 of “something which is,” “something having esse.”
This complex apprehension is primarily a judgment but is ex­
pressed briefly by the noun "being.”
B. THE METAPHYSICAL KNOWLEDGE OF BEING

But the being that we derive from sensible things by direct per­
ceptual judgments and the judgment of implicitation is precisely
the being of sensible things, not being as being. Hence, we have
not yet reached the being of metaphysics. Can we go from sensi­
ble being to the being of metaphysics by abstraction? If we sup­
pose that we do, we would imply either that ( 1 ) a sensible tiling
**Thc coined term "implication” is used to indicate that the knowledge
which is common by indefinite reference is a nonabstractive knowledge of
singulars. Some authors, borrowing an expression from Cajetan, call the
process “abstraction by confusion.” A student—at least an English-speaking
one—will be confused by a misleading translation of what was at best an
awkward term.
In principle, the judgment of implicitation could arise from the insight
into the difference between “this” and "is.” In practice, the experience of
several things is the ordinary ground for the judgment of implicitation.
21A simple apprehension or concept is an act by which the mind grasps a
nature or quiddity without affirming or denying, but simply considering it
absolutely in itself. In addition to this sort of understanding, there is another
type of conception, which, although not an explicit judgment, has arisen
from a preceding judgment in such a way that the judgmental function of
knowledge of esse remains. Cf. Klubertanz, The Philosophy of Human
Nature, pp. 178-180.

42

CHAPTER H

[12]

contains both sensible being and being as being, so that we can
abstract from the former to have only the latter, or (2) that the
“sensible” part of sensible being is nonbeing and so can be ab­
stracted from to have pure being. Both of these alternatives have
no ground in our experience: we directly see a sensible tiling
which is, and that-which-is in a sensible thing is-scnsibly. Hence,
the supposition that we reach being as being by abstraction is
false.28
Let us re-examine the process we used above when we tried to
determine what it means to be real.28 We saw that all the beings
of our experience are indeed sensible and material. But reflection
on our own acts of intellectual knowing and willing kept us from
making a facile identification of being with materiality. Rather,
the nonsensible reality of thinking and willing forced us to en­
gage in a further inspection of the sensible real. Now, a sensible
reality is (1) some kind of thing, which is (2) acting or being
acted on, and is (3) singular, (4) sensible, and (5) material. We
examined each one of these aspects of a sensible thing and saw
that either singly or taken together they are indeed real—pro­
vided the thing in question truly is. But equally it became clear
that although the thing happens to be a singular material thing,
it is not real because of its singularity or its materiality and sensi­
bility, or because of its essence or action, but precisely because it
is (exists). In other words, over and above the direct perceptual
judgment that “This is,” we make a negative judgment, inasmuch
as we see that “It is not precisely because of matter and so forth
that the thing is.” This special negative judgment is called “sepa­
ration,” 80 for by it we separate the intelligibility of what it means
to be from the intelligibility of what a sensible, material, quiddity
or essence is.31
* One of the reasons for this is taken up in Selected Passages, No. 7.
* Sec above, secs. 9 and 10.
“Some authors call separation “abstraction in the wide sense,” or “the
third degree of abstraction.” These expressions arc confusing at best; see
above, n. 23; at worst, they betray abstractionism and essentialism.
"This point is discussed in Selected Passages, No. 5.

[12]

THE NfEANING OF “BEING”

43

Perhaps it will help us to understand the judgment o£ separa­
tion if we consider it as a summary negation including a scries of
specific negations which are probably not made all at once. Most
likely, the first of these negations is the understanding that reality
is not a ’'property” of any particular thing or due to any form of
singularity. Next, we may come to realize that activity is not iden­
tical with reality when we learn that things remain real even
when we do not experience their action. Then, we come to under­
stand that sensibility' is not identical with reality', for even popu­
lar science tells us of realities that we cannot sensibly experience.
As we come closer to a philosophical grasp of being, we see that
matter is not simply the whole of reality or the principle of real­
ity, even in a material thing; this we see when we come to under­
stand that matter is potential and determinable. Finally, by a still
more difficult reflection, we come to understand that essence is
not identical with reality and being, and this we do partly by
reflection on the many, widely differing kinds of tilings that exist
and partly by reflection on essences that are mere objects of
thought.32
In the formation, therefore, of the complex intelligibility of
“being as being,” we make two judgments:33 (1) “This (sensible)
thing is,” and (2) “Even for this sensible thing to be is not the
same as for it to be a particular sensible or material thing with a
definite essence.” This judgment does not imply that we know
that an immaterial being exists or that we think that such a being
is possible.31 At the present stage of our investigation, we do not
** This consideration is clinched by a detailed investigation of real change,
for if “to be an essence" were identical with "to be or to exist” change would
be impossible; see below, sec. 34.
“ Two judgments are necessary, not three, because the judgment of sepa­
ration can do all that the judgment of implicitation does and more. How­
ever, someone may take this in three steps: (1) the perceptual judgment;
(2) the judgment of implicitation; (3) the judgment of separation.
M It is extremely important to note that just as a material being is not a
being because it is material, but because it is, so, too, an immaterial being
(if such there be) is not a being because it is immaterial, but because it is.
In general, the kind of essence a being has does not make it a being; what­
ever its essence, it is a being because and inasmuch as it is.
Hence, it is illusory to attempt to base a knowledge of being as being on

44

CHAPTER II

[12-13]

know demonstratively that there are immaterial beings. The sec­
ond of these two judgments—the judgment of separation—may
sometimes be only implicit, in the way in which it is implied, for
example, in the explanatory phrase, "Being as being is something
which is inasmuch as it is."
In this analysis of the beings of our experience and of our
knowledge of them, we have been dealing throughout with sensi­
ble, material existents. The point of our consideration has been
to establish a scientific knowledge of the properly real. We have
seen that a real thing which exists, is material, has a singular
essence, and acts is real precisely because it exists; and that in
such a thing, that in virtue of which it is is an act—its act of exist­
ing. The scientific understanding5*5 of the properly real, “being as
*
being/
is formed through an implicitly double judgment, in
which we have our first explicit knowledge of existence.
13. The first principles of knowledge
A principle of knowledge is some knowledge from which some
other knowledge follows or flows. In reasoning, the premises arc
the principles of the conclusion. But not all principles are first
principles, for some principles are themselves conclusions from
some other premises. A first principle is one that is not proved
from or developed from some other, prior principle. There are
first principles in every demonstrative knowledge, though it can
often happen that some of the first principles of some science (for
example, physics) are developed in another science (for example,
mathematics). If we want to speak of first principles, wc must
therefore distinguish between first principles in some particular
order and absolutely first principles. In the absolute sense of first
the demonstrated existence of immaterial things. Either "is" is freed from its
sensible and changing context (prior to the proof of the existence of imma­
terial being, and thus is meaningful when wc conclude to the existence of
such being) or “is" remains as we first find it immersed in sensibility and
change. In the latter case, “is” means “is sensible, material and changeable,”
and to assert that “An immaterial, immobile thing is sensible, material and
changeable" is a contradiction.
• See also below, sec. 20, on the “unity” of the knowledge of being.

[ 12-13 ]

THE MEANING OF “BEING”

45

principles, sense experience is a first principle of human knowl­
edge.
In the order of intellectual knowledge itself there are two first
principles, one in the order of apprehension, the other in the
order of judgment. In the order of apprehension, being is the first
principle, for, as will be shown in the philosophy of human na­
ture, being is the proper object of the intellect, and every con­
cept, other than being, is understood in some relation to, or as an
elaboration or determination of, being. In the order of judgment,
the first principle, on which all judgments rest, is the “principle of
contradiction": “It is impossible to affirm and deny the same thing
of the same subject at the same time.” We can also state the prin­
ciple of contradiction in terms of being: “A thing cannot both be
and not be at the same time." 30
Because metaphysics is the demonstrative knowledge of the
real as real, wc must briefly consider, in a preliminary way, a
question that has been asked by various philosophers throughout
the whole history of philosophy, namely, “Can there be a reality
which cannot be known by us?” If wc arc working with a con­
cept of essence or with the common notion of being, then wc will
not be able to answer the question at this j>oint, and perhaps we
would have to give an affirmative answer. But if wc arc working
with being as lx?ing, then we can say immediately, "Any alleged
or proved reality, since it will be, in some sense of the word,
something, and since it will be, can be known by us as being.” 37
And in the same way the principle of contradiction will be ap­
plicable to any present or proved or alleged reality.
The truth, as well as the absolute applicability, of the principle
of contradiction is known simply in understanding that principle.
We discover that a thing cannot both be and not be at the same
time when we experience something which is, understand it, and
reflect and compare it with its opposite. If wc ask, “Where and
* Per se known principles are mentioned briefly in Selected Passages,
No. 6.
" This point will be taken up again in secs. 64 and 74.

46

CHAPTER II

[13-15]

how do we find the principle of contradiction?” the clear answer
is: “Inductively, in experience." If we ask, “How or where do we
know the truth and universality of that judgment?” the answer is
“In itself, that is, in what we understand when we affirm that a
thing cannot both be and not be at the same time.” In other words,
when we experience a being and understand the act of existing,
it is precisely that act and our insight into it that grounds our
judgment. For this reason, a principle like this is called “per se
known” or “analytic.” 38
Sometimes it helps our understanding of a per se known propo­
sition to take a negative and dialectical approach to it, in other
words, to try to see whether we can suppose it to be false. Sup­
pose a man were to say, “It is true that affirming and denying the
same thing can be done at the same time.” In that case, his af­
firmation itself is affected by what he says, so that the affirmation
does not exclude a simultaneous negation—in other words, his
affirmation turns out to be meaningless. In other words, no man
can really think the opposite of the principle of contradiction,
although he can form a meaningless string of words which looks
like a denial of that principle.

14. Definitions
A real tiring, in the proper sense of the word, is an actually
existing thing, one which exists in itself and is not merely an ob­
ject of thought.
‘"An analytic principle is one which can be discovered to be true from
an analysis of what it says. When the term “analytic” is used as here de­
fined, it is correct to call first principles analytic. But there are other mean­
ings of the term which are not suitable. (1) The Kantian meaning (“An
analytic proposition is one in which the predicate is drawn out of the sub­
ject by analysis”) cannot be applied to any of the principles of meta­
physics. (2) There is another meaning which implies that both of the terms
which compose the proposition are first known separately by two distinct
simple apprehensions, then the content of each apprehension is analyzed,
and finally the judgment is made. Such a process is possible in some per se
known propositions (for example, in the proposition, “Incorporeal things
do not occupy space”), but certainly it is not possible with the principle
of contradiction or with many other principles, such as the principle of
causality.

[ 13-15 ]

THE MEANING OF “BEING.”

47

A real thing, in the wide sense of the word, is something which
is, was, will be, or at least can be.
Materialism is the philosophical doctrine that tilings are real
inasmuch as they are material.
Essentialism is the philosophical doctrine that things are real
inasmuch as they are or have an essence or quiddity.
Being is something having esse (an act of existing).
Being as being is something having esse inasmuch as it is,
exists.
A univocal concept is one which is true of many individuals in
exactly the same sense.
Abstraction is the act of considering one intellegibility of a
thing without considering others with which it is associated in
the real order.
Intelligibility is a characteristic, trait, or aspect (of a thing)
which can be understood by the intellect (ratio).
Total abstraction is the consideration of the nature or quiddity
of a thing without consideration of its individual determinants.
Formal abstraction is the consideration of the formal determi­
nants of a thing apart from other determinants of that same thing.
Implicitation is the making implicit or suppression of the sin­
gularity of a singular thing without abstracting it.
Judgment is that act of the mind by which we assert (or deny)
that a tiling is (was, will be), or that it is modified in some way.
Simple apprehension is the simple and absolute grasp of what
a thing is (concept).
Complex apprehension is an intellectual grasp of an intelligi­
bility by way of or through a judgment.
Separation is a negative judgment: a judgment by which we
deny that one (thing or intelligibility) is another.

15. Summary of the argument
A. The real is properly being.
The real tilings of our immediate experience, though they are
sensible and therefore material, are real, not because they are ma­

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[ 15-16 ]

terial or because they are what they are or because they are
singular but because they are, exist.
Comment. To be real does not mean to be material, because
matter in itself is determinable and is not the principle of actual­
ity and determination; nor does it mean to be acting, because
acting follows being; nor does it mean to have an essence or to
be singular, because quiddity and essence do not serve to distin­
guish the properly real from the real in the wide sense and so
cannot be the principle of the properly real.
B. Being as being is not reached by abstraction but by separa­
tion.
The act of abstraction belongs to the first operation of the
mind, which concerns quiddities or essences and leaves some­
thing out of consideration. But being is not merely a quiddity,
and there is nothing outside of being which could be left out.
Yet being as being is not the same as being material, and tin’s
denial or negative judgment is called separation.
16. Readings

St. Thomas Aquinas, On the Power of God, q. 7, art. 2, ad 9 (that
is, the seventh question, the second article, answer to the ninth
argument; this answer is a very condensed but comprehensive ex­
pression of the primacy of esse); Contra Gentiles, Bk. II, Chap. 54
(especially the paragraphs beginning “First” and “Secondly”; this
passage explains that the whole thing is that-which-is); Summa Theo­
logiae, Pt. I, q. 5, art. 1. ad 1 (the meaning of “being,” in comparison
with the meaning of “Good”); Summa Theologiae, Pt. I, q. 40, art. 3;
Compendium of Theology, Chap. 62 (these two passages speak of the
two types of abstraction).
Etienne Gilson, Being and Some Philosophers, 2d cd. (Toronto,
Pontifical Institute of Mediaeval Studies, 1952), pp. 203-205, on the
difference between the simple concept and the judgment, and on our
knowledge of esse.
Robert J. Henle, S.J., “Existentialism and the Judgment,” Proceed­
ings of the American Catholic Philosophical Association, Vol. XXVI
(1946), pp. 40-53. This is a detailed and very penetrating analysis of
the importance of the act of existing in the philosophy of being and of
the judgment as our only adequate knowledge of esse.
Oliver Martin, “An Examination of Contemporary Naturalism and

[15-16]

THE MEANING OF “BEING”

49

Materialism,” Return to Reason, ed. John Wiki (Chicago, Regnery,
1953), pp. 68-91; an excellent study of the inadequacy of materialism.
Wihnon H. Sheldon, “Critique of Naturalism,” Journal of Philosophy,
XLII (1945), 253-270; pertinent to our present interest is the critique
of naturalism as a form of materialism.
Gerard Smith, S.J., "Before You Start Talking about God,” The
Modem Schoolman, XXIII (1945), 31-32; the importance of a prop­
erly metaphysical understanding of being.
John Wild, “What is Realism?” Journal of Philosophy, XLIV
(1947), 148-158, discusses the meaning of “real”; the main stress of
this article is on the opposition to various more or less mitigated forms
of idealism.
Selected Passages from St. Thomas Aquinas

4. What Is the Subject of Metaphysics?
. . . [Aristotle] says, first, that there is a demonstrative knowledge,
which considers being as being, as its subject, and considers also
“those things which of themselves [per sol arc in being,” that is, the
per se properties of being.
But he says, “as being,” because other demonstrative knowledges,
which deal with particular beings, do indeed consider being—for all
the subjects of knowledge are beings—yet do not consider being as
being, but as it is some kind of being, that is, “number,” or "line” or
“fire” or something of this sort.
He says also, “which of themselves are in this,” and not simply,
which are in this, to show that it does not belong to this demonstrative
knowledge to consider those things which accidentally are in its sub­
ject, but only those things which of themselves are in it. . . . This
demonstrative knowledge, whose subject is being, should not con­
sider all the things which accidentally are in being, because thus it
would consider everything which is considered in all kinds of knowl­
edge, for everything is in some sense læing, but not inasmuch as it is
being. . . . The necessity of this knowledge which considers being
and its per se properties, is clear from this, that these things should
not remain unknown, since the knowledge of other things depends on
them, as the knowledge of proper objects depends on common
ones. . . .
Here he shows that this knowledge is not one of the particular
knowledges, from this consideration. No particular knowledge con­
siders being universally as such, but only some part of being divided
from other parts. And about this part it considers the per se proper­
ties. . . . But the common knowledge considers universal being as
being, and so it is not the same as any of the particular knowl­
edges. . . .

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[16]

Here he shows that this demonstrative knowledge, which we have
before us, has being as its subject, this way. Every principle is of
itself the principle and cause of some nature. But we are seeking the
first principles of things, and the highest causes (as was said in the
first book); and these are of themselves causes of some nature. But
this is only the nature of being. And this is clear from this, that all
philosophers, investigating tire elements inasmuch as they are beings,
sought this kind of principles, namely the first and highest. Therefore
in this demonstrative knowledge we are seeking the principles of
being as being. Therefore being is the subject of this knowledge, for
every demonstrative knowledge seeks the proper causes of its subject.
Commentary on Aristotle’s
Metaphysics, Bk. IV, lect.
1 (ed. Cathala, Nos. 529533).

5. Abstraction Contrasted with Separation
The response. It is to be said that for the evidence of tins question
we must know how the intellect can abstract according to its opera­
tion. We must know therefore that according to the Philosopher in the
third book of the De Anima, there are two operations of the intellect:
one which is called “the understanding of indivisibles,” by which it
knows what anything is; the other, by which it composes and divides,
that is, by forming an affirmative or negative proposition. These two
operations correspond to two (principles] in the thing. The first
operation considers the very nature of the thing, according to which
it has a definite place among beings, whether it be a complete thing,
like a whole, or an incomplete tiring, as a part or an accident. But the
second operation considers the very esse of the thing, wliich follows
from the coming together of the principles in a composite thing, or
accompanies the simple nature of the thing, as in simple substances.
And because tire truth of the intellect lies in this, that it is conformed
to the thing, it is clear that according to this operation, the intellect
cannot truly abstract what is joined together in the thing, because, in
abstracting, a separation according to the esse of the tiring would be
signified, as, if I abstract man from whiteness, saying "man is not
white,” I mean there is a separation in the thing. Hence, if in the real
order man and whiteness are not separated, the understanding will be
false. And so according to this operation the intellect cannot truly
abstract except such things which are separated in the real order, as in
saying, “Man is not an ass." But according to the first operation of the
mind, it can abstract things which in the real order are not separate,
not all indeed, but some. . . .
Thus the intellect distinguishes one from another in different ways
according to different operations, because, according to tire operation

[ 16 ]

THE MEANING OF “BEING”

51

by which it composes and divides, it distinguishes one from another
in this, that it understands one not to be in the other. But in the
operation by which it understands what everything is, it distinguishes
one from another, inasmuch as it understands what this is, understand­
ing nothing about something else, neither that it be with the other,
nor separated from it. This latter distinction, therefore, is not properly
called separation, but only the former. . . . Since abstraction cannot
take place, properly speaking, except of things which are joined
together in reality, according to the two modes of conjunction (that
is, the way in which the part and the whole are united, or fonn and
matter), there are two kinds of abstraction: one by which form is
abstracted from matter, the other by which the whole is abstracted
from the parts. . . .
And so there are two abstractions of the intellect: one which
corresponds to the union of form and matter or accident and subject,
and this is the abstraction of the form from sensible matter; the other,
which corresponds to the union of the whole and the part, and to this
there corresponds the abstraction of the universal from the particular,
which is an abstraction of the whole, in which some absolute nature is
considered according to its essential intelligibility. . . . But in such
things which can be divided according to their esse, we rather have
separation than abstraction.
Thus, in the operation of the intellect there is a threefold distinc­
tion. There is one according to the operation of the intellect composing
and dividing, which is properly called separation, and this belongs
to the divine knowledge or metaphysics. There is another according
to the operation by which tire quiddities of things are formed, which
is the abstraction of a form from sensible matter, and this belongs to
mathematics. There is a third, according to the rame operation, of the
universal from the particular, and this belongs also to physics, and is
[in some way] common to all knowledges, for in every demonstrative
knowledge we omit what is accidental and take what is per se.
Commentary on Boethius’s
De Trinitate, q. 5, art. 3.

6. Principles Known Per Se
Those things which are per se known to us, are made known im­
mediately by sense experience, for example, when a whole and a part
arc seen, we immediately know that ever)' whole is larger than its part,
and we know this without any investigation. Therefore the Philosopher
says, “We know principles when we know their terms” (Posterior
Analytics, I).
Commentary on the First Book
of the Sentences, dis. 3, q. 1,
art. 2.

52

CHAPTER II

[16]

7. Abstraction and the Knowledge of Immaterial Substance
A certain philosopher, called Avempacé, held that through the
understanding of material substances, following the true principles of
philosophy, wc could arrive at an understanding of immaterial sub­
stances. For, he contended, our intellect has such a nature that it can
abstract the quiddity of a material thing from matter; if there is still
something material left in that quiddity, the intellect can abstract
once again; and since there cannot be an infinite series of material
principles in a quiddity, finally the intellect can arrive at an under­
standing of some quiddity which is entirely without matter. And this,
he maintains, is to understand an immaterial substance.
This reasoning would l>e effective, if the immaterial substances were
the forms and essences of the material things present to us, as the
Platomsts maintain. If we do not take this position, but rather take
the position that immaterial substances arc of an entirely different
kind than the quiddities of material things, then, however much our
intellect abstracts the quiddity of a material thing from matter, it will
never obtain anything even similar to an immaterial substance. There­
fore through material substances we cannot perfectly know immaterial
substance.
. . . immaterial substances cannot be known by us in such a way
that we apprehend their quiddities, but we can learn something about
them through the way of removal [separation] and of relation to
material things.
Summa Theologiae, Pl. I, q.
88, art. 2 and ad 2.

CHAPTER III

The First Analogy of Being
17. The fact of knowledge in common
We have already seen that some kind of common knowledge of
individuals is necessary for every kind of organized, demonstra­
tive (scientific) knowledge. By “common knowledge” we mean
a single knowledge that is true of many things. For instance, it is
true of any sample of water that water is H2O. So, too, the law of
freely falling bodies is true of any and all such bodies; the laws
of learning arc verified in their way in every case of learning; the
theory of the cellular structure of living things is applicable to a
great variety of living things. And similar examples of common
knowledge can be drawn from any science, from mathematics,
logic, and philosophy.
Sometimes, logicians and grammarians speak of equivocal
terms as common. An equivocal term is one and the same term
(same in sound or spelling) that has different senses and signifies
different kinds of things. An example of an equivocal term is
“bank,” which can mean the ground bordering a river or an es­
tablishment for the keeping and lending of money. We can speak
of an equivocal term if we refer to an external sign. But an equiv­
ocal term docs not imply common knowledge, because equiv­
ocal terms have entirely different meanings.1

18. Univocation and its basis
The kind of common knowledge with which we should be most
familiar is univocation. By univocation we mean the use of one
1 Kinds of common terms are spoken of in Selected Passages, No. 8.
53

54

CHAPTER III

[18-19]

and the same term and its corresponding knowledge to apply to
each of many individuals in the same sense. Examples of uni­
vocation can be found in the use of everyday terms like “water/
“sheep,” “tree,” as well as in scientific terms like “vertebrate,”
“triangle,” “syllogism.” A univocal term is given its name because
of the identity of meaning (uni- means one; -vocation here means
naming). Often a univocal term is called a universal because it
can be applied to all the individuals of a given kind in exactly the
same sense.
How can one and the same term rightly be applied to a number
of individuals which are different? how can one and the same act
of knowledge include (explicitly or implicitly) many different in­
dividuals? There must be a double basis for this. We have already
seen the basis for univocation when we considered abstraction;
because some knowledge abstracts from particularities we can
deal with what-things-are univocally. But in order that abstrac­
tion be legitimate, there must be some kind of distinction be­
tween what-a-thing-is and its particularity. For the present, we
are not going to consider what this distinction is or on what it
is based. It is enough if there is some kind of distinction between
the essence of a thing ( whal-a-thing-is ) and its particularity.2

19. Is being a universal?

We have already seen that our knowledge of being is not an
abstract knowledge, and consequently it cannot have the same
kind of community that an abstract knowledge has. But we must
investigate the basis for this more closely.
First of all, individuals are or exist. Can we convert this propo­
sition and say, “All existents are individuals?” We can approach
the answer to this question by considering whether nonindivid­
uals can exist.
Now, a nonindividual is either a formal (or reflex) universal or
a simple universal (an absolute nature). A formal universal is
defined as that which is known to be common to many and pred1 This distinction is considered in detail in sec. 33.

[ 18-19 ]

THE FIRST ANALOGY OF BEING

55

icated of them (for example, the species "man," the genus "ani­
mal”). If a formal universal were to exist as such, as existing it
would be not common, but a distinct thing in itself. But it is a
contradiction to suppose that one and the same thing should be
both common and not common at the same time. Hence, the sup­
position that “A formal universal exists” is false.
A simple universal or absolute nature is that which is absolutely
meant by terms like "man,” “horse,” “animal,” "car,” and so forth.
It is that which we predicate whenever we predicate a noun or
attribute of a subject. As such, it is not formally universal (else it
could not be predicated of many); it is neither really existing nor
a mere object of thought. Now, some thinkers suppose that such
absolute natures exist, either in themselves or as distinct elements
in things. For example, in the horse Citation, there are said to be
as many distinct nonindividual elements as there are distinct
ways of knowing what Citation is (for example, horse, swift,
rangy)- But this supposition involves a number of unintelligible
or contradictory consequences: that something which is potential
(can be either singular or universal) is also actual, namely, an
actual element of a real thing; that something can be neither
singular nor not-singular (that is, not merely be considered ab­
stractly, but be abstractly), and therefore that contradictory
propositions are not completely opposed to each other; that the
real thing is composed of distinct elements, each of which taken
singly is indifferent or neutral to reality'. But any supposition that
involves impossible or unreal consequences is not true. Therefore
it is not true that an absolute nature or essence exists as such.
Hence, only individuals exist, or, all existents are individuals.
Being means that which is, and so it includes the particularity' of
that which is. But being does not determinatcly include the par­
ticular; in other words, being does not necessarily mean this thing
or that thing; it means any, or, a thing. This special way' of signi­
fying the particular as particular we shall call "indefinite refer­
ence,” because it makes use of the indefinite article to signify a
very definite, concrete, singular thing.

56

CHAPTER ni

[ 19-20 ]

Consequently, being is not a univocal nor a universal term.
Being is not univocal, for whenever we assert that something is,
we speak of a unique individual which has an act of existing all
its own. Hence, being is not universal, for no two individuals can
be exactly alike inasmuch as they exist.

20. Being is analogous
Thus far we have seen a number of points which are the data
for tlie problem of the community of being. We will consider
them in summary form.
(1) Only concrete individuals exist and can exist in the real
order.
(2) An individual real thing is an existent and formally a being
because of its act of existing, not because it is material or
is what-it-is.
Nevertheless, the beings of our experience are mate­
rial things of a particular kind.
(3) Being that is presented to us by the real existents of
which we have direct experience includes both a thing­
element and esse.
Being is an intelligibility, the ratio entis; it is that
which we understand when we know a real thing as a
being.
(4) Each existent presents itself as an individual thing distinct
from all other things, that is, as a unique subject of esse.
In other words, each individual thing is a unique way
or mode (manner) of having esse.
(5) As tlie subjects of esse differ from each other, so also do
the existential acts.
For example, this dogs existential act is different from
that dog’s, just as this dog is different from that.
(6) Hence, each individual thing exists with its own act of
existing.
It would be foolish to imagine that one thing or per­
son could exist with the act of existing of another.

[ 19-20 ]

THE FIRST ANALOGY OF BEING

57

(7) And yet being is realized in each existent.
Every real thing is manifestly a singular definite thing
having its esse.
Thus, being is common to all things.3
But the problem is how being is common. Being, in any singu­
lar existent, cannot be entirely and exactly the same as it is in any
other thing. It must in each instance be and be known as a defi­
nite singular thing uniquely ordered to its own act of existing. It
must in each instance include all that is unique and proper to the
singular individual, and so it cannot be an univocal intelligibility.
Since, on the other hand, the intelligibility, being, is presented to
us by, and verified in, any singular concrete existent, being can­
not be equivocal. (As we have already seen, no intelligibility can
be equivocal; only terms can be equivocal.) Being, therefore, is
somehow midway between uni vocation and equivocation, and
hence we say it is analogous, that is, similar.
Being is never presented by any two beings as exactly the
same. In other words, being, as presented by one existent, is al* Though most Thomists subscribe to the formula of Cajetan, "being is
simply many, but one secundum quid," they also maintain that it is one con­
cept and is predicated analogously. Is there one concept of being? Of course,
there are all sorts of "concepts of being,” from Hegel to Sartre; even some
self-styled Thomists have a "concept” which they call "being”—one, unique,
confusedly containing all its inferiors, and so on. Such a concept is not the
being which is tlie subject of metaphysics.
Because beings are analogous, they cannot be correctly understood in
any one concept. But long familiarity has accustomed us to use the unity
(even if it is only partial and derivative) and ignore the multiplicity (even
though it is basic).
Most philosophers want to go too rapidly; they overlook the basic im­
portance of the verb is. For the first problem of metaphysics is, “What does
is mean?” "How do we predicate is of differing individuals?” The verb­
predicate "is” should be investigated before we even ask about the attribu­
tive noun, “being.” We understand and assert is analogously, and this
analogy demands our first attention. The failure to realize that is can be a
verb which expresses existential act is the capital fault of logicism (or
essentialism ) and distorts both the ordinary spontaneous experience of in­
dividuals as well as metaphysics. To substitute a noun and a concept for
the verb is a serious error. At best, the problem of metaphysics is poorly
expressed as a problem of unity amidst diversity; at worst, being is turned
into an essence or form in order that it may have a true conceptual unity.
See also below, sec. 72.

58

CHAPTER III

[20]

ways and necessarily and intrinsically different from the being
presented by another. From one existent I derive one intelligi­
bility; from another, another; and so on. These intelligibilities arc
alike only inasmuch as each unique intelligibility is proportion­
ally similar to any other. And they arc intelligible according to
this proportional likeness. That is to say, we can and do recog­
nize that as this unique thing is to its unique act of existing, so
any other unique thing is to its unique act of existing. When we
intellectually compare any one being as a being with any other
being, we recognize this proportional relationship. The individ­
ual, unique way (manner, potency, capacity) of having an act of
existing in each instance precludes the forming of an univocal in­
telligibility.4 What we form, if we proceed aright according to
the demands of the real order, is many intelligibilities propor­
tionally alike. As long as these intelligibilities remain direct
knowledge of the real as it is, they are simply irreducible to one
intelligibility.5 So when we speak of being we are merely saying
indefinitely, “any unique thing having its own act of existing,”
thereby expressing the obvious diversity of any one being from
any other, and, at the same time, the recognizable proportional
likeness that obtains among beings.
The likeness or similarity of beings can be stated in other
words. The unique way in which this singular thing is related 6 to
its esse, and vice versa, is similar to the unique way in which any
other singular individual is related and proportioned to its esse,
and vice versa. We can represent to ourselves this situation by the
following diagram:
This particular thing (A)
That particular thing (B)
its own esse
' ‘
its own esse,
and so on. Things in the real order—according to their intelligi*See above, secs. 11 and 12.
• See above, n. 3, and below, sec. 72.
•This "relation” is not a predicamcntal but a “transcendental” relation;
see below, sec. 93.

[20]

THE FIRST ANALOGY OF BEING

59

bilitics as beings—present themselves as similar in that each
tiling manifests a unique proportion to its act of existing, and
vice versa.
This intelligible similarity (likeness) in being is not univoca­
tion, as we have already seen; nor can it be reduced to a combina­
tion of univocation and equivocation, as it would be if the esse '
were exactly the same in each existent and the thing-element
simply diverse. For any given act of existing is the act of existing /
of some tiling; it is, therefore, itself particular, different from any
other act of existing. Beings as wholes are similar, not by having
like parts (that would be univocation) but by having similar
relationships of simply diverse parts. The similarity between any
two individual existents is precisely a similarity between unique
proportions (relationships). This kind of similarity and commu­
nity is called the “analog}' of proportionality.” “Analogy” is a
technical term for a similarity that cannot be reduced to a com­
bination of identity and difference. “Proportionality” is a techni­
cal term for relationships with paired terms.7 Since tilings are
thus really similar or analogous, it is necessary that our knowl­
edge and predication of being, also be analogous. In other words,
both the noun “being” and the verb “is” can be rightfully used
in our knowledge and speech only as analogous. The diversity of
existents as beings prevents the univocal predication of being.
We are here dealing with being in its primary meaning, as the
real order presents it to us. We arc speaking of the intelligible
similarity found between one existent whole formally understood
as a being and any other existent whole understood in the same
way. The analog}' of being is therefore primarily and basically an
analog}' between beings—between any two or more real things
having their own act of existing.
Later on, we shall sec that there are relationships and analogies
within beings, that is, between the various principles of being.
T Proportionality and proportion are mentioned in Selected Passages,
No. 9.

60

CHAPTER III

[20-22]

We shall also discover another kind of analog}' ( causal analogy )
between some effects and their causes, and a still different kind of
analogy between God and all other beings.8
Hence, not all analogy is analogy of proportionality. Nor is
every relationship of paired terms analogous. For example, con­
sider a mathematical series like 2/4:3/6:4/8:5/10, where the rela­
tion (double) is univocal. It is tine that here the parts are
diverse; but there can be an identical (univocal) relationship be­
tween them, because we are dealing with simple abstract objects.
Once abstracted from esse, singularity, and intrinsic differences,
objects as known can literally possess formally the same intrinsic
perfections? But when we are dealing with the relationships in­
volved in being, univocation is impossible.
In summary, then, being is analogous. It cannot be applied to
any two beings with exactly the same meaning. It is not a uni­
vocal intelligibility, for every being is unique and particular.
Being is not obtained by any kind of abstraction, properly so
called. On the other hand, the term “being” is not equivocal. One
being is simply diverse from any and every other being, but it is
also similar to any and every other being of our experience by a
similarity of proportions. Between any two or more beings as we
find them we discover a similarity of intrinsic proportions be­
tween what-it-is and its esse. Being is therefore analogous by an
analogy of proper proportionality.
•See below, secs. 31, 32, 49.
At this point it is traditional to treat of metaphor, and it is frequently
said that metaphor is “the analogy of extrinsic proportionality.” Thomists
point to texts like Summa Theologiae, Pt. I, q. 13, art. 6. It should be noted
that metaphora is a Greek term, translated into Latin as translatio, and
means nothing more titan “figure of speech” ( as a proof of this, note that St.
Thomas instances causal attribution as well as what is commonly recognized
as metaphor in the passage cited). At the first level of analysis, metaphor is
the extrinsic attribution of an alien nature; see Robert R. Boyle, S.J., “The
Nature of Metaphor,” The Modem Schoolman, XXXI (1954), 267-230.
For a suggestion about an underlying analogy in metaphor, see below,
Chap. IX, secs. 63, 67.
* For the reason why this is true, see below, Chap. V, n. 12.

[20-22]

THE FIRST ANALOGY OF BEING

61

21. Definitions
A univocal term (and knowledge) is one that is applied to
many individuals in wholly the same sense.
An equivocal term is a term that has the same external sign
(same in sound or spelling) but entirely different meanings.
An analogous term (and knowledge) is one whose meaning is
not exactly the same; nor is it entirely different; it is not merely a
combination of a univocal and an equivocal element but that
which is the same is somehow also different.
Analogy of proportionality is a similarity of relationships of
diverse parts, principles, and so forth.
An analogue, or analogate, is one of the things, terms, princi­
ples, and so forth, to which an analogous term is applied or of
which an analogous knowledge is true.

22. Summary
A. Only individuals exist.
Nonindividuals are either formal universals or absolute natures
(simple, or direct, universals).
But: neither formal universals nor absolute natures exist (a)
because formal universals must be one in order to be what they
are, and that which is one is not-many and therefore not-common,
yet an existing formal universal should also be common to many;
and (b) because absolute natures, which can be either singular
or universal, cannot simultaneously be fully actual. Absolute na­
tures cannot exist as such in singulars, because a real thing cannot
be composed of elements each of which is indifferent to reality.
Therefore: no nonindividuals exist, or only individuals exist
B. Being is not a universal.
A universal is an abstract and univocal term.
But: being is not abstract, for it includes the whole real thing;
nor is it univocal, for it includes all real differences.

CHAPTER IV

Becoming—Change—Motion
24. The problem of change

We have just engaged in a detailed consideration of the fact
that things are. That things change is a fact which is also directly
known, and the investigation of what change is will occupy us for
the next three chapters. Some philosophers have found difficulty
in admitting both being and change at one and the same time.
Some of the essentialists, in defining reality as that-which-iswhal-it-is, have combined permanence with this self-identity so
much so that they consider the changing to be unreal. Some have
even gone so far as to assert that all change is an illusion. We can
take as a simple example of this kind of position the argument of
Parmenides, an Italo-Greek who flourished in the early fifth cen­
tury before Christ. According to this Greek philosopher, the real
or being is that-which-is-what-it-is. If the real were to change, it
would have to be what-it-is (by definition) and at the same time
what-it-is-not (on the supposition that it changes). But this con­
sequence is a contradiction, and so the supposition is false. Again,
we can consider this position from another point of view. To
change is to become other than what one was. Now, the real is
what-it-is, and that which is other than (or opposite to) the real
is notliing. So, change would be possible only if the opposite of
the real were also real; but this is false, and so change is impossi­
ble. This is a very simple position, but more elaborate forms of
it have been held at various times.
The position which Parmenides was criticizing was that of
Heraclitus, an Ionian Greek of about the end of the sixth century
B.c. He was impressed by the unity of the universe and by its
64

[ 24 ]

BECOMING—CHANGE—MOTION

65

ceaseless activity and change. It seemed to him that if change is
real, then everything which is real is change. And so Heraclitus
not only asserted that change is real, he denied that anything is
permanent in being. Everything is in flux, in process; he found
the best example of his notion in the restless, ever changing fire.
An elaborated form of this opinion has been held at various times
and is relatively popular at the present time. Many modern phi­
losophers express their notion of it by saying that there is no
substance, no thin'' which acts; there is only activity without an
agent. They deny the reality of the things and persons which we
immediately perceive, not because their perception is any differ­
ent than ours but because they cannot see how they can admit the
reality of both change and being.
Are we really forced to choose between change and being? It is
easy to see that those who chose being and denied change did so
because for them “to be” was “to lie an essence”; to lie real was
to be what a thing is. But the strange thing is the same faulty
understanding of being led others to the opposite position of
denying being in favor of change. Accepting the notion that “to
be” is “to be unchangeably and permanently what a tiling is,”
they have also accepted the immediate evidence that the things
of our experience are in constant, more or less perceptible change.
Because they are empiricists, they prefer facts to theories. In their
minds, the fact is that change is going on; the theory is the notion
of being as “that which remains what it is ” Rightly questioning
this notion of being, they have failed to ask a more fundamental
question: “What is it to be real?”
Hence, since we have seen that to be is to exercise an act of
existing, and since we have direct and undeniable evidence that
change is going on, it is necessary to ask whether change is in­
compatible with being when being is understood as that-whichis.
By change, we understand "becoming different.” We must
therefore investigate what is meant by “sameness" and “differ­
ence.”

66

CHAPTER IV

[25]

25. Identity, distinction, and difference
Identity is sameness, oneness of a thing with itself. We say that
a thing is identical with itself when it is the same at two points of
time, or under several considerations, and so forth. Identity is
absolute when all the characteristics, traits, and so forth of a tiling
are the same. Identity is partial, limited, or qualified, if some of
the characteristics, traits, and so forth are the same, and others
are not the same. Several types of limited identity may be pointed
out as examples. Numerical identity is the basic sameness of one
and the same individual along with various minor changes; we
speak, for example, of the numerical (personal) identity of one
and the same person throughout his life. We speak of specific
identity when we have two individuals which belong to exactly
the same kind of reality; for example, in geometry we speak of
identical triangles. We speak of the material or real identity of a
tiling which we are thinking of in several ways; for example, John
Doc as father of a family is materially identical with the same
John Doe as a business man, but he is being considered now with
one set of relations, now with another.
Distinction is Jack of identity. It always implies plurality and
division of some sort or other, for wherever there is a distinction,
títere must be more than one thing or part or aspect. Distinctions
are basically of two types: real and of reason. A real distinction is
found wherever there are really several things, parts, elements,
and the like, independently of any act of the mind. A real dis­
tinction and a real identity' arc opposed as contradictories: that is,
a real identity denies a real distinction, and vice versa. A com­
mon sign of a real distinction is separability: wherever two tilings
or parts can be separated, such that one can exist without the
other, those things or parts are really distinct. But not every real
distinction implies the separability of those things or parts which
are distinct. When the distinction is between complete things or
beings, we speak of a real major distinction. When the distinction
is between the parts ( elements, principles ) of one thing, we call

[ 25 ]

BECOMING

CHANGE—MOTION

67

it a real minor distinction (for example, the distinction between
a man’s hand and his foot; or the distinction between his color
and his shape).
A distinction of reason is not a distinction within the thing it­
self but a lack of identity between two ways of understanding
one and the same real thing. A typical example of the distinction
of reason can be found in the parts of a definition: "rational
animal,” which is the essential definition of man, is composed of
two parts. What we understand when we say “animal” is differ­
ent from what we understand when we say “rational”; but the
tiling we understand in these two incomplete ways is one and
the same. When at least one of the two concepts (between
which there is a distinction of reason) does not imply the other,
the distinction of reason is a major one. For example, though
“rational” does imply “animal,” yet “animal” docs not imply "ra­
tional,” and this we can find as well from an inspection of these
two concepts as from the fact that there are animals which arc
not rational. On the other hand, when both concepts imply each
other, we speak of a minor distinction of reason; an example of
such a distinction we will find later on is the distinction between
“one” and “being.”
Difference can mean the same as distinction in some of its uses,
but often the term “difference” is used to express the reason for
a distinction. In our usage, the term “distinction” will more com­
monly be used to indicate that one thing (part, element) is not
another; the term “difference” will be used to indicate the way in
which things differ or, sometimes, that by which things differ. Of
the differences between tilings two will lie mentioned frequently
in the material which will be considered next. A “numerical dif­
ference” is that between two individuals which belong to the
same species or kind; for example, there is a numerical difference
between Peter and Paul, between two shepherd dogs, two trees,
two chairs. An “essential difference" is the difference between
two things, which, in addition to being individually different, also
are of different kinds or species. In logic, we learn that a defini-

68

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[25-26]

Hon is composed of a genus and a difference and that things are
said to be specifically different when, having a common genus,
each has some attribute proper to itself by which it differs from
the others (this proper attribute is called the “difference”). But
in logic any common notion suffices for a genus, and any less
common one for a difference. In metaphysics and the philosophy
of nature we do not work with such arbitrary classifications.
Rather, we try to determine as accurately as possible what things
are according to their intrinsic constituents. When this has been
done, and we find that the intrinsic constituents of one are dif­
ferent from those of another thing, then we say that the things
differ essentially.
Now, it is obvious from our own past experience that we
cannot simply look at a thing and know at once, immediately,
what it essentially is. We have to learn what things are, and we
discover this by seeing directly what they do. Thus, we often
cannot tell by looking at a thing whether it is alive or dead. But
we watch it act, and so we learn what it is. Briefly, we learn the
essence or specific nature of a thing from its activities or opera­
tions. This must also be the method by which we discover specific
or essential differences. Two things are discovered to be essen­
tially different if one of them has some operations which the other
docs not have. Thus, living things have some activities ( nutrition,
growth, reproduction) which other material things simply do not
have. Hence, living things are essentially different from non­
living things.

26. A changing thing has really distinct components
We began this chapter with a problem urged by many philoso­
phers that there is some kind of incompatibility between being
and change. For clarity’s sake, we decided to obtain a clear
understanding of the terms involved in considering change. We
saw that change means “to become other than something was.”
s So we undertook an examination of difference, distinction, and
identity. Now we are ready to look at change as it actually hap­

[ 25-26 ]

BECOMING---- CHANGE---- MOTION

69

pens, and our purpose is ultimately to discover the relation be­
tween change and being. In order to keep our discussion concrete
and in touch with reality, we shall use as an encample the change
of a seed into a tree.
What do we mean when we say that a seed changes into a
tree? We mean that there was first an initial stage in which there
was a seed with a definite size, shape, and structure; secondly
that there was some kind of process; and thirdly that there is a
terminal stage at which the process arrives, in which the tree has
a quite different size, shape, and structure.1 ( Note that the initial
and terminal stages are not absolutely initial and terminal but
are such relatively to each other and the process.) Moreover,
there must be some continuity between initial stage, process, and
terminal stage. If, after the seed was planted, some one came,
replaced the seed with a seedling, then with a very small tree,
then with a larger tree, and finally with a very large one, we
would not have an instance of real change in one and the same
tree (but an illusion of change if we did not know the difference,
and a mere succession of different things if wc did).
Let us examine this analysis more closely. For something to
change is for it to become other than it was. To become is to
come-to-be; in other words, becoming is a process which termi­
nates in being. Because there must be a continuity throughout
the process, and because the differences of initial and terminal
stages cannot ground that continuit)', there must be something
common, namely, a subject which undergoes that process.2 For
convenience and brevity, wo will make some use of the following
symbols:
XY—the initial stage, the subject with its characteristics as it is be­
fore the change takes place.
XZ—the terminal stage, the subject with the characteristics it has
after the change.
P—the process itself.
X—the common subject, the thing which changes.
1 For the relation of succession to change, see Selected Passages, No. 11.
’ On the common subject in change, see Selected Passages, No. 10.

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X is therefore both XY and XZ; but this is not a contradiction.
Before X changes, it can be what it will be after the change is
completed. Hence, at the point at which X is XY, X is said to be
in potency to XZ. After the process, when X has become XZ, it
actually has the trait, characteristic, or perfection to which the
process was originally directed. Hence, after the change, X is now
Z in act? We can summarize this by saying, “X is both XY and
XZ; when X is XY in act, it is in potency to XZ; when it is XZ in
act, it is no longer in potency to XZ; if the process is reversible,
when X is XZ in act, it is in potency to XY.” For example, when
a thing is hot in act, it is in potency to being cold; when it is cold
in act, it is in potency to being hot. This distinction between
“being in potency” and “being in act” enables us to see that
change and being are not mutually exclusive as Heraclitus and
Parmenides thought. This distinction, moreover, gives us a new
way to define change: for a tiling to change is for it to become
in act what it was in potency.
The analysis of change can be pushed still further, by investi­
gating the nature of that which changes. We have seen that, first
of all, a real change involves a subject which is present through­
out the change; and this subject we have designated X. Secondly,
after a process of real change, the thing which changed is differ­
ent—XZ is different from XY. The subject of change must have
either acquired something which it did not have in act before
or lost something which it had in act or lost one characteristic
and acquired another. Schematically:

XY-------J P---------- >XZ
• Note that we are here dealing with two conditions of a being: "to be
in potency,” and "to be in act.” These two conditions are related to, but
by no means identical with, the principles of potency and act which will
be studied in Chap. VI. To discover the principles of act and potency is
much more difficult than the analysis which is being made here. Moreover,
au attempt to pass from the present consideration to the principles of act
and potency will result in univocal concepts of act and potency—a con­
sequence that will vitiate the whole understanding of metaphysics.

[26]

BECOMING

CHANGE—MOTION

71

To show more clearly how the common subject continues
throughout the change, we can diagram it thus:

Y.
X

P

■>

Z.
X

To illustrate the three ways in which change can occur (to gain,
to lose, to gain one and lose another), we can make our scheme
more detailed, using a for a positive initial perfection, b for a
positive terminal perfection, and c for the common subject:
not-fc

a

r,

1

b
c

a
T,
not-a
c ——
*

a__ _
c

b_
c

Can tile one or the two positive perfections which are gained or
lost or interchanged be identical really with the common subject
which changes? Can either a or b be identical with c? Clearly,
these three components cannot be really identical. If we suppose
they arc really identical, then either there is nothing really com­
mon—and so there is no change, but removal of one thing and
the substitution of another whole thing (Heraclitus)—or there is
nothing really gained or lost, if we choose to say that the common
element which is identical with all its stages is the real thing
(Parmenides). Therefore, in a real change, at least one of the
terms of the change must be composed of two really distinct
components.
There are various types of components in a whole being. The
term, “part” (although it sometimes is used to mean "any com­
ponent or constituent”) most often means “an equal constituent
portion,” and in this usual sense it is equivalent to an “integral
part.” Examples of integral parts are the parts of a human body,
the parts into which a line can be divided. Integral parts usually
are quantitative parts of an extended (and measurable) whole.
There are other types of components which are not quantitative
in character, which cannot be discovered by direct sense experi­
ence, and which are not capable of existing as distinct beings

72

chapter iv

[26-29]

after the division of the whole. Such components we will call
“principles,” that is, intrinsic or constituent principles.
In a real change, the components must be really distinct; a dis­
tinction of reason cannot account for a real change. If the being
which changes is one being, then the component principles will
be distinct with a real minor distinction.
Now that we have developed, through an instance of real
change, a pattern by which we can understand how change
occurs, we are ready, in the following chapter, to look at various
kinds of change.

27. Definitions

Change is the process of becoming different or other than
something was. ( This term stresses the difference between initial
and terminal stages. )
Becoming is the transition or process from being in potency to
being in act. (This is the technical, scientific definition; the term,
“becoming,” stresses the relation of process to being. )
Motion in the strict sense (local motion) is change of place or
position.
Motion in the wide sense is any change which can be directly
measured by time, any change which is continuous or gradual in
character.
Motion in the widest (or transferred sense) is any change.
Identity is the sameness of a tiling with itself.
Distinction is lack of identity.
Beal distinction is a lack of identity independent of any act of
the mind.
Distinction of reason is a lack of identity dependent upon an
act of the mind.
Being in act is the condition of really possessing some perfec­
tion or modification.
Being in potency is the condition of not really having, but
being able to acquire, some perfection.

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BECOMING---- CHANGE---- MOTION

73

28. Summary

A. Change and being are not incompatible.
Change involves an initial stage, an intermediate process, and
a terminal stage. The subject of the change at the beginning is
in potency to the determinations which it will have in act at the
end.
Hence, change and being are not mutually exclusive or com­
pletely incompatible; rather, because change is directed toward
being in act, it implies being. Yet, they arc not identical either
but are related as process and term of the process, as motion and
the point of arrival of the motion.
B. Things which change are composite.
Whatever undergoes a real, intrinsic change must be different
in its terminal stage from what it was in the initial stage, and
yet there must also be a common subject.
But: that by which the initial stage differs from the terminal
stage cannot be really identical with the common subject (and
this subject is necessary for the continuity of the two terms).
Therefore: that which changes must be composed of a common
principle which is in potency and (at least in one of the stages) a
principle by which the stages differ.
29. Readings
Aristotle, Metaphysics, Bk. IV, chaps. 5, 6 (lOlOalS ff. 1011b34),
Bk. VIII, chap. 1 (1042a32); Physics, Bk. I, chaps. 7-9 (190a32192b2), on change; Bk. Ill, chaps. 1-3 (200b.l2-202b29), on motion.
Jacques Maritain, Introduction to Philosophy, trans. E. I. Watkin
(New York, Sheed and Ward. 1933), pp. 50-51, 60-63, 239-246.
John Wild, Introduction to Realistic Philosophy (New York, Haiper,
1948), pp. 277-295, on change.
Selected Passages from St. Thomas Aquinas

10. A Common Subject in Change
Because every change is from one contrary to another, it is necessary
that a subject underlie them, which subject can be changed from con­

74

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[29]

trary to contrary. This the Philosopher proves in two ways. First, be­
cause one contrary does not change into another: for blackness itself
does not become whiteness. Therefore, if there is to be a change from
black to white, there must be something besides blackness which can
become white.
The same thing he proves in another way, from this consideration
that in every change something remains. For example, in a change
from black to white a body remains, but the other thing, namely, one
of the contraries—black, for example—does not remain.
Commentary on Aristotle's
Metaphysics, Bk. XII, lect.
2 (ed. Cathala, Nos. 24292430).

Everything which is changed remains with regard to some element
of it and with regard to some other element ceases to be. For exam­
ple, that which is changed from whiteness to blackness remains with
regard to its substance. Thus, in everything which is changed, some
composition is to be found.
Summa Theologiae, Pt. I, q. 9,
art. 1.
11. Change Implies Succession
Since every change has two terms which cannot be together . . .
in every change or motion there must be succession, for this reason
that tire two terms cannot be together. Hence, there must also be time,
which is the measure of that which is before and after, and this, latter
is the essential note of succession. But succession occurs differently in
different cases. For sometimes the end of the motion is remote from its
beginning. Between beginning and end there may be the medium of
dimensive quantity, as in the local motion of bodies, or in the motion
of growth and shrinking. There may be the medium of virtual quantity,
whose division is related to the intensity and remission of some form,
as in the alteration of sensible qualities. In both of these cases, time
directly measures the motion itself, because there is a successive prog­
ress to the term, for it is divisible.
Sometimes, however, the term of the change is not remote from the
beginning, as in those changes which arc from a privation to a form
or vice versa, as in generation and corruption, and illumination, and
all things of a like nature. Even in these changes, time is involved,
since it is evident that matter is not simultaneously under a form and
the privation of that form, nor is tire air at once subject to darkness
and light. However, time is not involved, in the sense that the going
forth or passage from one extreme to the other takes place in time.
But to one of tire extremes ( that one, namely, which is first lost in the

[ 29 ]

BECOMING---- CHANGE—MOTION

75

change) there is joined a motion or alteration (as in generation and
corruption), or the local motion of the sun (as in illumination), and
at the term of that motion there is also the term of the change. Yet
that change is said to be sudden, or in an instant, for this reason that
in the last instant of the time which measured the preceding motion,
there is acquired that form or privation of which formerly nothing
was present. And in that instant we say that something has been gen­
erated, but not properly that it is being generated. . . . Consequently,
all such instantaneous changes are the terms of some motion.
Commentary on the First Book
of the Sentences, dis. 37, q. 4,
art. 3.

CHAPTER V

The Intrinsic Principles of Change

and Being: I. In Particular
30. Accidental change and the substance-accident
composition of being

We must now take up the study of change more in particular.
The first thing that we will need to reflect on is that there are
different kinds of change, at least descriptively speaking. For ex­
ample, there is the kind of change that is typified by the various
changes that one and the same person goes through in the course
of his life. There are changes in size, in bodily appearance, in
knowledge and character acquired, in activity, in relations with
others. Then there is another type of change most strikingly
exemplified in the death of living tilings; a dead dog, for example,
is just not a dog any more.
Our present consideration will concern the former type of
change, and we will begin with a number of examples. A piece
of wax is at one time in the shape of a candle; at another time it
may be globular or a lump of irregular shape. A baby frog has
no legs, a full-grown frog has legs and has lost its tail. A
scraggly tree may be trimmed into a regular shape. Birds fly
from one tree to another. Some things change in size, particularly
living tilings; a giant redwood, hundreds of feet tall and with a
trunk many feet in diameter, was once a little seed. Some things
change in activity; trees grow during spring and summer, and
show no signs of such activity during winter; animals sleep, run,
eat, and some hibernate during the winter months; men also
76

[30]

INTRINSIC PRINCIPLES IN PARTICULAR

77

change activities in much the same way as other animals (eating,
sleeping, moving about), and they also change in their thoughts
and desires, they grow in knowledge and acquire virtues or vices.
Now, each one of these beings undergoes a real change; the
changes we have been speaking of are not like the changes of
clothes on a show-window dummy; they are changes within
being. The being, considered as a whole, is different after the
change from what it was before. Yet there is also in some way an
identity. The wax that changes its shape is the same wax; the frog
or tree that grows is the same frog or tree; the adult, mature
man is the same human person that he was as a baby, a child, a
young man. We know this because the changed thing does
basically the same kind of activity before the change as after.
We know what kind of thing a being is by seeing what kind of
activities it has. We can sum up all these examples this way:
in the kind of changes described above, the being that changes is
the same kind of thing that it was before the change, and it is
the same individual. In other words, there is a subject that at one
time existed under one modification and then later on under
another.
In the preceding chapter, we saw that there must be a real ?
distinction between the subject of the change, the common ele­
ment, and the determinations or qualifications which arc gained
or lost. But the components of a changing thing are not them­
selves whole beings but principles or parts. Hence, the dis­
tinction between these components is a real minor distinction.
What can we say about these various components and their
relations to each other? In the kind of change we are considering
here, the subject remains what it was, in the sense that it retains
the same nature and individuality. But in itself, this subject can,
and often must, receive further determinations; for example, the
wax must have some shape, but it need not have any particular
shape in order to be wax. Because this subject “is under” (“sub­
stands”) the various determinations or modifications, it is called
a “substance.” Thirdly, though a substance can receive further

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[36-31]

determinations, the substances which change in our experience
themselves exist or are in their own right, in themselves.
On the other hand, the various modifications come and go; we
speak of them as “coming to” or “happening to” a substance;
hence they are called “accidents”1 (ac-cidens, “that which hap­
pens to”). The function of an accident is to modify or determine a
substance.
Both substance and accident are principles of being. But they
are not equal principles; they are not exactly of the same kind.
Substance is that in a being by which the being remains of the
same kind throughout an accidental change and by which the
being has an act of existing in itself. Accident is that in a being
by which the substance is modified in some definite way; the
nature of accident is to be the modification of a substance (its
subject), and in this sense to be “in” the substance. Hence, phi­
losophers often say that accidents inhere in substance. Substance
and accident will be considered in detail in Chapters XI-XIII.
31. Substance and accident as beings by analogy

We have seen that the properly real thing, or the being, is the
entire thing-which-is. We have also seen that the first components
or principles of being discovered are substance and accident. In
our analysis of accidental change we saw that the principles of
being cannot themselves be beings in the same way—it would be
impossible that a principle of being should itself be something
which is. Nevertheless, if substance and accident are the prin­
ciples of die real, they must also be real themselves, since the
real is not made up of unrealities. How then can substance and
accident be real? In the sense that they are constitutive principles
of that-which-is. Since substance is the ( more or less ) permanent
* The term “accident” is also used in a logical sense, and in logic it
means “that which is not necessarily connected with the essence of some
thing.” It is also used in a popular sense, “something (usually something
harmful), which was unforeseen, unintended, and so on.” We can call the
meaning of accident used in the body of the text the “metaphysical acci­
dent.”

[30-31]

INTRINSIC PRINCIPLES IN PARTICULAR

79

nature of the thing and is that in the thing by which an existent
has esse in itself, the act of existing pertains, within the being,
most closely to substance. In other words, substance is not a being
all by itself; but the esse of the whole being is also the esse of all
the principles of that being, not equally but in proportion to the
way in which the principles constitute that being. Now, sub­
stance is the constitutive nature of that-which-is, and so we can
properly and directly say that a substance exists. Substance,
therefore, is directly proportioned to the act of existing; we can
say directly and without any qualification, “A man, a cat, a dog, a
tiger exists.’’
Accident, on the other hand, is related to that-which-is, not of
itself but through substance. The nature of an accident is to
modify the substance in which it is. In other words, accident,
according to its nature, is not in itself but in another.2 Since acci­
dent naturally depends on substance for its being, we can say that
accidents are, not directly but by inherence. For example, we
can say, “Whiteness exists—in white things.” Here we have an
analogy of the constitutive principles of being, based on the rela­
tionship of these principles to each other and to the whole which
they constitute. These relationships make it possible for us, more
or less properly, to call both substance and accidents beings,3 and
so we call this analogy the “analog}' of proportion (by inher­
ence).” Briefly, substance is being by its direct proportion to the
act of existing of the whole, since it is that in the being by which
the being has an act of existing in itself. Accident is being by its
proportion to substance in which it inheres, for when an accident
modifies the substance of a being, the whole being exists, by that
accident, in a modified way. For a concrete example, when wc
say, “A dog is,” we mean, “Some individual existent is, having the
nature of a dog as the principle by which it has esse-in-itself.”
When we say, “Whiteness is,” we mean, “Some individual existent
’ See below, Chap. XII, especially secs. 88 and 90.
* See also, Selected Passages, No. 13. For the relation between the analogy
of proportion and the analogy of proportionality, see below, see. 108.

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[31-32]

is, having in itself as one of its modifying principles the quality
of whiteness,” or, more simply, “Whiteness does truly modify the
substance of some being,” “Whiteness truly inheres in the sub­
stance of some being.”
32. Substantial change and the matter-form
composition of substance
In the discussion of accidental change, we considered those
changes in which the changing being remained the same kind
of thing and the same individual that it was. However, there are
also other changes in which the thing after the change is of a
different nature than the thing before the change. The clearest
examples of essential change can be found in the death of living
things. A live animal has a certain nature, which is shown by the
fact that it can perform certain kinds of activities. When the
animal dies, the dead body of the animal is simply incapable of
vital activities, and so is essentially or specifically different from
the living thing. A very similar example can be found in the
nourishment of living things. In nourishment, some nonliving
material is changed into and becomes a part of a single living
thing. In this case, two beings of different kinds become one
being.
Our experience shows us that there are some accidental
changes which prepare for and are the means of bringing about
the change of nature. And there arc still other accidental changes
which are necessarily consequent upon the specific change. To
illustrate this from the examples given above, we know that
whether death is violent or natural, in cither case some disposi­
tions or qualities are changed by force or disease or simply by
the wearing out of the organism. And we know also that proper­
ties of a nature arc necessarily connected with the nature, so
that when the first nature is present, these properties arc present,
and they go with the nature, while tlie new nature which is the
term of the change brings with it its own properties. But over
and above these accidental changes, there is a change of the

[31-32]

INTRINSIC PRINCIPLES IN PARTICULAR

81

nature itself, which is made known to us from the kinds of activi­
ties that tlie two beings in question perform.4 Hence, there is a
change in tlie very substance of the thing changing.
By applying our analysis of change to these changes of sub­
stance from living to nonliving, we get the diagram:

(1) Living substance — changes to-----> nonliving substance
I_____________________ ___________ , n
c
~
* c

(2) Living 4- nonliving — change to-----» one living substance

Hence, all substances which undergo substantial change are
composed of two intrinsic principles. One of these principles is
that by which a substance is of a definite kind: living, nonliving,
and so forth. This principle has received the name of “substantial
form”—substantial, because it is the determining principle of sub­
stance; form, because it has the same relation to its coprinciple as
shape or structure has to the materials used. Substantial form is
the principle by which a substance is the kind of substance it is;
therefore, it is not itself a substance, much less a being, and so
it is not a reality which we could possibly find in our direct sense
experience or by any instrument. Note that in metaphysics we
deal only with substantial form as a principle of substance and
being without qualification; in the philosophy of nature we shall
discover that there are different kinds of substantial form and
that one kind of form ( the human soul ) is not only a substantial
form but also a principle of operation and of being.
The second of the two coprinciples of substantial change and
composition cannot of itself have any particular nature, since it
is precisely the common element in the change of nature or kind.
It is of itself merely a subject of change, and for this reason it is
4 To establish this fact we are using knowledge at the subscientific level.
Ju the philosophy of nature, substantial or specific changes and specific dif­
ferences are considered and proved at the level of demonstrative knowledge.

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[32-33]

called “primary matter” or “first matter.” It is called primary
matter because it is the first principle of the most basic type of
change and is determinab/e to any nature which material things
can have. Since substantial form is not a thing or a being or a
substance properly so called, much less is primary matter a thing
or a being. Of itself, primary matter is not actually any kind of
tiling; nor does it have quantity or any kind of qualities or other
accidents. Hence, primar}' matter cannot exist in itself; it cannot
be found as such in direct or indirect sense experience; it cannot
even be understood separately from substance or substantial
form. It is an intelligible coprinciple and so is real as a principle
of substance and can be understood only in the same way.5
Are primarj- matter and substantial form really distinct? Since
the changes which are explained by these coprinciples are real
< changes, matter and form must be distinct with a real minor dis­
tinction. In a way, matter and form are like substance and acci­
dent, yet there are also many differences. One of these differences
is that accidental change can be gradual because the subject of
accidental change (namely, substance itself) is the actual prin­
ciple by which an individual is in itself. But substantial change
must be instantaneous since the subject of substantial change
(namely, primary matter) is purely determinable. Substantial
changes seem to take time because of the accidental changes
which are the means of substantial change.0
Another approach to the composition of sensible things is de­
rived from a consideration of the various ways in which accidents
are related to their subjects. On the one hand, we find that there
are specific qualities and properties which indicate different
kinds of things. What one thing is is different from what other
things are; what each thing is is characterized by determination,
actuality, and some kind of fixity. Hence, substance, which is the
“See also, Selected Passages, No. 12.
"That continuous change implies primary matter is established by St.
Thomas in his Commentary on Aristotle’s Metaphysics, Bk. VIII, lect. 1
(cd. Cathala, No. 1686). But this consideration seems to belong to the
philosophy of nature rather than to metaphysics.

[32-33]

INTRINSIC PRINCIPLES IN PARTICULAR

83

proper subject of accidents, must itself have these characteristics.
On tlie other hand, we also find that some modifications are
common to all material things—chief among them being quantity
and the continuous way in which their contingent accidents vary.
Thus, we find two sorts of modifications of substance: one char­
acterized by being proper (that is, not common) and relatively
fixed, the other by being common and fluid or relatively "form­
*
less.
’ But this distinction of accidents cannot be based on a
simple, indivisible substance, for a simple subject cannot be the
source of contrary dispositions. Hence, material substances are
composite, made up of two principles, one of which is deter­
mining and specific (substantial form), the other, common to all
material things and in itself indeterminate (primary matter).
Primary matter and substantial form are not things or beings;
they are not each, properly speaking, a substance. But they are
principles of substance; by them a substance is respectively
capable of substantial change, relatively indeterminate, and like
other material substances, and, at the same time, actually of a
given kind or species, determinate, and different from other kinds
of material tilings. Hence, these two principles can be called
substances—not in the primar}' sense of that term but by an
analogy of proportion, inasmuch as they are proportioned to each
other and to the substance which they constitute. They are re­
ducible to the category of substance.
33. Individuals in a species and matter-form composition

So far we have been considering material substances with
regard to their real changes and real internal constitution. There
is another important consideration of material substances whose
point of departure is our knowledge of them.
We have already noted that in material things there are many
individuals having one and the same specific nature. When we
know the nature of a being, we know it by universal knowledge
which is true of all the individuals having that same identical
nature. Yet each individual is itself really different from every

84

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[33]

other individual. We have already seen, in Chapter III, that the
universal as such cannot exist either as a separate being or as a
really distinct part of a being. Therefore, in Peter, for example,
man is not really distinct from Peter nor from Petreity.
On the other hand, universal knowledge cannot just be a fiction
of the human mind.7 That which we know in our universal knowl­
edge is somehow found in the real order. Comparing our knowl­
edge to reality we find the situation which can be diagrammed in
this way:
The real being, Peter, who
is individual throughout

is known
by means of

pnan
[Petreity

Therefore, if our knowledge is true, there must be some reason
or foundation in tilings for our knowing them universally and
particularly, and yet this foundation cannot be a common nature
as common really distinguished from particularity.
As metaphysicians our concern is precisely with the structure
of the beings that can be known by universal knowledge. Our
problem is to determine what ultimately in the constitution of
such beings is the basis or foundation of their intelligibility as
specifically the same.
Let us turn back to the distinction we have discovered between
’ We are here appealing to many evidences for a moderate realism. First
of all, we do have true knowledge of a world of sensible beings distinct from
ourselves, and wc know the existence of these beings by our intellect but
through sense perception. This evidence cannot be proved, first, because it
is an evidence; secondly, because sense perception is a principle of all our
knowledge, as will become clear from the philosophy of human nature.
Secondly, there arc many considerations which particularly concern uni­
versal knowledge. Pragmatically speaking, universal knowledge can be used
as a means to deal with real singulars. More deeply, when wc mentally
construct fictions wc are aware of our activity in that construction and can
trace the process, but in knowing singulars by direct universal knowledge
we do not find ourselves constructing a fiction. Ultimately, we can see that
our universal knowledge is a knowledge of the thing which exists. It is not
a complete knowledge but one which abstracts from singularity. However,
to abstract is not to deny. It would be false to deny that things are singular;
we have a true but incomplete knowledge when we know a singular tiling
without knowing its singularity. To develop these brief considerations is
die task of an epistemology or theory of knowledge.

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primary matter and substantial form. Substantial form is that
by which a substance is what-it-is, that is, has such a nature or
essence. Priman,' matter is that by which a thing is capable of
substantial change and which therefore is the subject or recipient
of substantial form. As such a recipient, primary matter is the v
ontological ground for the possibility of there being many indi­
viduals (for example, many men) in the same species. The
individual substantial form that Peter has and the individual form
that James has are such that we, by abstraction, can obtain from
either one of them a nature of the same intelligible content
(man). Individual existents are so structured that this is possible,
and so we rightly say that they possess specifically the same sub­
stantial form.
Our statement is not, however, sufficiently accurate. There
must be many subjects for specifically the same substantial form.
How are these subjects distinguished from each other? By the
division of priman' matter. Now, primary matter cannot be
divided in itself, since in itself it is purely indeterminate, and divi­
sion implies distinction, difference, and so some kind of de­
termination. If we consult experience, we find that an individual
is that which is here and now? But, as we shall see later more
explicitly, here and now are functions of quantity. Quantity or
extension is such that it has parts outside of parts and of itself is
divisible. Hence, primary matter with quantity or dimensions9 is
•Of course, individuals frequently differ in many ways. Practically, we
can often identify an individual by some quality—"the curly-headed one.”
But such traits “identify” an individual only within a limited situation;
absolutely speaking, we cannot single out any quality of a sensible thing
which could not, at least in principle, also be equally present in another.
Take, for example, two pins, two crystals, two “identical twins.” Tilings can
still be two even if these two have no discoverable qualitative differences.
Two material beings cannot be two beings unless their temporally deter­
mined locations are different. This is not meant to deny "compénétration”
or the possibility of a subatomic particle "passing through a solid”; if such
events do happen, they are nevertheless explained by means of differences
in the “here” and “now.”
•At any given moment, the dimensions in question arc the actual three
dimensions of the particular individual limited by the external surface;
these are called “determinate dimensions.” But because in some individuals

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that which is the principle of individuation*10*of a material thing.
There are many individuals in a species inasmuch as the recipi­
ents of specifically the same substantial fonn are divided from
each other in relation to tridimensional extension.
It will help us if we compare the order of logical composition
(common nature 4- individuality) with the quite different order
of real composition ( substantial form + primary matter + quan­
tity).
( 1 ) In the order of logical composition,

man
+
Petreity

John

James

Peter

•

man
]
+
r
Jamesness J

■

man
+
Johnness

(2) In the order of real composition,11

Peter

James

John

f = substantial form by which each individual is a man.
p — the primary matter.
x, y, z = the diverse quantities.
The subscript letters indicate the determination [designation] of mat­
ter by diverse quantities.
(living things) the dimensions change—between limits—during their lives,
we must consider their dimensions with their variable limits; these are called
"indeterminate dimensions.” By indeterminate dimensions we mean the
three-dimensional quantity of an individual, with variable limits, as it were,
“at the center.”
10 The principle of individuation is that in the particular thing by which
that thing has its particular part or share of the specific perfection and so is
only one of many in the species. Distinguish this term from “individuality."
Individuality is the sum total of positive perfections pertaining to this in­
dividual as this individual. Individuation is the quasi-negativc, limiting
principle; individuality is the correlative, positive perfection.
u Because the diagram is somewhat complicated, here is how it should be
read: “In the real order, Peter, as this man, is composed of a substantial
form ( principle of specific perfection ) and of a primar)' matter distinguished
in function of a particular quantity plus the quantity which has the function of designating primary matter as this (principle of individuation).

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Once this has been understood, we can easily come to see how
new individuals arise by the division of previously existing ones.
This is basically the way in which new living beings arise; we can
see it most simply in the origin of new unicellular organisms.
Many of these organisms are multiplied by simple division
(fission); one individual divides into two individuals which are
numerically distinct from each other, and yet each of the new in
dividuals has the undivided perfection of the species or kind of
living tiling. Diagrammatically:

form____________
matter,, + quantity

_________

form_________
matter,,1 + qu1
form_________
matter,,2 + qu2

From our consideration of individuation, we arrive at a fuller
understanding of the relationship between matter and form.
Form of itself as form is simply what-it-is; it is the principle of
determination, actualization of specific or substantial perfection.
But matter, as divided recipient or capacity, is the principle of
multiplication and limitation as well as of substantial change. No
individual has the full perfection of what-it-is-by-nature (that
is, through its form), because each form is concretely limited by
the matter in which it is received. For example, no man has the
full perfection of the human nature which he possesses through
his form (his soul), because each man’s soul is concretely limited
by the body (in the sense of primary matter) in which that soul
is received.12
“Some students arc bothered by the pseudo problem. What keeps a
separated soul from either ballooning up to be a universal or being iden­
tified with all other human souls? All cxistents are singular; if the soul exists
after death, it exists as a singular and with the singularity and existence it
had before. Along these lines, there arc only two reasonable questions that
can be asked. ( 1 ) How can separated souls, which are singular forms, be
known by universal knowledge? (2) In what sense can a separated soul be
said to be the “soul of Peter’? The answer to both questions is the same:
because each separated soul has been the soul of a given individual and
permanently retains a relation to that individual’s body.
Other students are confused because it seems to them that geometrical

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This relationship o£ form and matter may perhaps be better
understood by a consideration of a kind of being about which
various philosophers have spoken, namely, the separated sub­
stances, also called “angels,” "pure spirits,” "pure intelligences,”
and so forth. There are a number of very subtle and difficult argu­
ments by which the existence of such beings is suggested and
proved. Neither the time nor the background is available to us
here, so we will speak of such beings hypothetically. If such
beings exist, their substance is not composite; they are not sub­
stantially determinable and so cannot undergo substantial
change.13 Furthermore, their substance is entirely determinate;
they are entirely what they are. There is nothing else in their
substance except their specific perfection. Hence this substance
is entirely expressed in a single individual, and consequently
there cannot be many of these beings in a single species. Each
one differs specifically from every other (and so in a kind of
way also “numerically”). Because they are pure forms, the
formal perfection of such beings is incapable of multiplication;
by a somewhat improper use of language, we could say that each
individual pure form is its own species (for there are really no
species among such beings).
34. That-which-is and the act of existing (esse)

So far we have found composition and distinction of principles
at the level of accident and activity and at the level of substance.
Because we can know what is by simple apprehension (con­
cept), but whether a thing is only in a judgment (affirmation or
negation), we are led to inquire into the relations between what is
and its act of existing (esse). It is quite clear that the questions,
figures, though pure forms (abstract, it is true, instead of real), arc multi­
plied by themselves without composition. Careful reflection will show that
such abstract forms are not multiplied by themselves qua forms, but by
"intelligible matter." In simpler terms, such abstract forms are multiplied
positionally» that is, by reference to a hypostasized extension which serves as
a receptive background. This substantialized quantity is quality-less, and
therefore individuates only numerically, i.e., without other distinctions.
“ See also, Selected Passages, No. 14.

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“What is it?” and, “Is it?” are two quite different questions. It is
also clear that as far as all the things in our direct experience are
concerned, the act of existing is not a specific perfection, not a
further determination of what the thing is. As Kant said, a hun­
dred real dollars are not a penny more than a hundred possible
dollars.
If we attentively reflect upon an existent as it is given to us in
immediate experience, we see first of all that the meanings of
to be and what-is are different. As we progressively understand
this difference between what-is and its act of existing, we form
the primitive understanding of being, “some (sensible) tiling
which is”; then, on the level of the scientific knowledge of meta­
physics, we are led to make the judgment of separation, and so
come to understand being as that-which-is. Now, however, we
need to study being still more closely.
Let us consider a being, for example, a person, present to us
in immediate experience. What that person is (namely, this
human being with all his accidental modifications) can be
grasped in a series of concepts and is analyzable into the prin­
ciples of matter and form, substance and accident. These
principles are principles of an existent, but they function as prin­
ciples which constitute the essence.14 These are the principles by
which the being is what-it-is, is limited, is capable of change in
various ways. But a being must be before15 it is determined,
limited, modified, capable of changes. What makes a thing to be?
“ On essence, see see. 12, n. 24. Historically, the term “essence” is used
in the strict sense to mean “the specific constitution of a tiling.” In this
sense, essence is that “part” or “aspect” of the substance of a thing which
constitutes it in its species. In the secondary sense, we can speak of the
essence of an accident as “that specific intelligibility of the accident accord­
ing to its kind, abstracting from its individual and contingent circumstances.”
In a wide sense, the term "essence” has been used to mean “what a
thing is.” In tliis sense, we can speak of an individual essence. Neverthe­
less, in the direct phenomenological analysis of concrete being, we first
find essence in the wide sense, as the thing-principle of that-which-is.
““Before,” in this sentence, does not mean a priority of time, but a
priority of nature and intelligibility. In other words, determinations and so
on presuppose an existent and depend on the act of existing of the existent
in order to be real.

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Precisely, the act of existing (esse). Thus, by direct inspection of
an existent we can see that essence and the act of existing are
really distinct. These principles, of course, arc not spatial or
integral parts (like the trunk and members of a living body) nor
essential parts (like matter and form). They are purely intelli­
gible principles, not observable as distinct but understood to be
distinct with a real minor distinction.
Indirectly, we can help ourselves to see this by two considera­
tions. The first of these begins with the evident fact that the
beings of our immediate experience are many and different. Each
one is some kind of being; each one has an act of existing limited
to a particular nature. If the act of existing were identical with
one nature, if, for example, the act of existing were identical with
what-it-is-to-be-horse, then, to exist would be to-be-a-horse, and
no other kind of thing could exist. But the consequent is not true,
and so the antecedent is false. Again, the act of existing is found
in many things, each of which as an individual is really different
from the others and none of which is simply and purely an act of
existing. But just as a substantial form cannot be multiplied or
limited of itself, so neither can the act of existing be limited of
itself nor multiplied of itself. Hence, unless there were a distinct
principle by which the act of existing is limited and multiplied
and in which that act is received, there could not be many
beings.16
The second consideration is the fact of change, particularly
of substantial change.17 We experience a tiling coming to be
’’Tin's point is explained more fully in Selected Passages, Nos. 1.5-16.
17 There are some philosophers, and even some Thomists, who think that
this proof is inadequate. They hold that (a) an explanation of change can
be given by means of the principles of substance and accident, matter and
form; (b) that the composition of these two principles is a sufficient basis
for the proof of the existence of God. Both of these statements are true
enough. One can give some explanation of change without going into the
question of the distinction between essence and esse. But if one remains
entirely on that plane, one is reasoning within the philosophy of nature, and
therefore should not expect to find anything about being as the meta­
physician considers being. The distinction between essence and esse is
implied in any metaphysical solution of the problem of change. If this

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91

and ceasing to be. But neither essence nor form (which is the
determining principle of essence) can change—horse cannot be­
come cow or carrion. A horse can die; but what-it-is-to-be-horse
cannot die or change in any way in itself. The unchangeableness
of an essence is simply a particular expression of the principle of
contradiction: "liorse is horse and cannot be not-horse.” If whata-thing-is and its act of existing were really identical, then the
horse-which-is would exist as necessarily as horse-is-horse. But
living things do die; things do change. Hence, what-a-thing-is
and its act of existing are distinct, with a real minor distinction.
Hence, what-a-thing-is and its act of existing are two really
distinct principles of a being. What-something-is, because it is
immediately related to esse (the act of existing), is often called
essence.18 Sometimes also that principle is called quiddity (from
the Latin quid, meaning “what”).19
35. The distinction between power and activity

We have just seen that the variations and changes in the
activity of living things are possible only if there is a real minor
distinction between the substance which continues to be and the
accidental variations which come and go. The relation of activity
to substance requires a little more investigation.20 We will be
distinction remains only implicit (as it did in Aristotle), the solution is
good as far as it goes, but it is incomplete. If, however, essence and esse
are thought to be identical in the real order, then each one of the com­
ponents of a tiling, such as substance and accident, which are essences, must
be identically also acts of existing. But that which is its act of existing cannot
lose it. All that could happen would be to move the necessarily existing
components around, and such an interpretation of change is the denial of
all intrinsic change. But intrinsic change evidently happens, and there­
fore essence and the act of existing cannot be identical in the real order.
11 “Essence” implies that we arc considering what a tiling is as a principle
of its being. "Quiddity” implies rather an absolute consideration of what it
is, as a pure intelligibility. Strictly speaking, therefore, metaphysics is in­
terested in essences but not in quiddities.
"See also, Selected Passages, No. 17.
“How we distinguish one activity from another and one power of
activity from another will be considered in another part of philosophy; cf.
G. P. Klubertanz, Philosophy of Human Nature (New York, AppletonCentury-Crofts, Inc., 1953), pp. 86-102.

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unable to complete our consideration of activity from the analysis
of experience,2’ yet we must begin it at this point, first of all, to
round out our consideration of the components of being in par­
ticular and, secondly, to give us the experiential content so that
our later study will not be merely verbal.
Most living things have one or more activities which are some­
times interrupted—by sleep, by climatic changes, by develop­
ment from immature offspring to senility, and so on. For example,
consider the conscious activities of a human being: he has certain
kinds of activities like seeing and thinking, and these change from
one act to another throughout the waking day; when he is sound
asleep, these activities cease altogether. Here, obviously, the
activity is distinct from the rest of the being, for it comes and
goes and varies, although the being itself continues in existence.
In all the things of experience, we find activity. There is no
existent which is absolutely deprived of all action. Even the most
passive-looking, apparently inert being is also active, as the in­
vestigations of physicists have abundantly proved. Activity is a
consequence, an overflowing into the order of action, of the
dynamism of the act of existing. What is the relation of activity
(action, operation) to the thing which acts? First, a thing acts
only if it exists; a nonbeing cannot do anything; a mere concept
cannot perform real actions. Secondly, a thing acts according to
its nature. In fact, we leam the nature of a tiling first and fore­
most from its activities. Not only is this true in fact; it is neces­
sarily true. For action comes from an agent; it is the fullness, the
complement of that agent’s being. The substance is that which
receives the other accidents and at the same time is the ultimate
principle of activity. Now, as we have seen, a substance in our
experience is what it is because of its substantial form, and, like­
wise, the same substantial form specifies the kind of activity
"See below, Chap. VI, sec. 40 (1). As we shall see, the distinction
between power and activity is proved partly by means of an a priori analysis.
One important distinction between two kinds of activity, immanent and
transient, will be made from the viewpoint of finality; sec below, sec. 55.

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which a given kind of being has. Hence, activity and nature must
necessarily correspond.
We must now raise the question, What is the relation between
substance and activity'? Does activity immediately inhere in and
immediately modify substance in itself, as do other accidents?
There is a preliminary and obvious fact that makes us suspect a
negative answer, and that is the fact that in material things
structure (which is an accidental principle, a quality) is an im­
mediate determinant of activity. But we cannot properly solve
tins question until we have studied the interrelations of the
various principles of being among themselves. Is the power to act
just another way of looking at substance? Or is it a really distinct
principle? These are the questions with which we conclude our
consideration of the constituent principles of being in particular.

36. Definitions
Accident is that principle of being whose nature it is to be in
another.
Substance is that principle of being which is modified or deter­
mined by accidents (nominal definition).
Substance is that principle of being whose nature it is to be
directly ordered to esse in itself ( real definition ).
Essence in the strict sense is substance considered as being of a
certain kind of species and being capable of receiving an act of
existing.
Essence in the wide sense is what a tiling is. It may include
substance and accidents (together as subject of esse); it may be
used of principles, of objects of knowledge, of operations, rela­
tions, and so forth.
Nature is substance or essence in relation to activities.
Analogy of proportion is that analogy which is based on a
single relationship between any two of the analogates; the analogates are not equal (do not have the perfection in an equal
degree), but one of them is prior to the other, and this order of
priority and posteriority is what makes the realities (and our

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knowledge of them ) analogous. ( The primary analogate has the
perfection first and independently, the secondary one, second,
and in dependence upon the first. Not every analogy is an
analogy of being; there is, for example, also the analogy of sub­
stance, as we have seen. )
Analogy of proportion by inherence designates that analogy of
proportion by which substance and accident, as unequal constitu­
tive principles of that-which-is are truly but analogously called
beings. ( Substance is the primary' analogate, since it is the prin­
ciple by which a being is in itself; accident is the secondary,
dependent analogate, since it is the principle by which, through
the modification of substance, a being is in a modified way.)
Analogy of proportion by information is the analogy by which
form and matter, as constitutive principles of substance, can truly
but analogously be called substance. (Form is the primary analo­
gate, as the determining principle; matter, the secondary' one,
inasmuch as it is proportioned to form and receives its order tc
being from form.)
Substantial form is the determining and specifying principle
of essence or substance.
Primary (first) matter is the determinable and limiting princi­
ple of substance in material things and, thereby, is also the com­
mon subject of substantial change.22
Individuation is the limitation of a nature to a particular in­
dividual.
Individuality is the sum total of positive perfections, or the
fundamental positive perfection, peculiar and proper to some
individual.
That-which-is is the principle by which a given thing has its
substantial and accidental perfections.
° Aristotle gives two classic definitions of primary matter. It is “the
primar>' substratum of each thing, from which it comes to be without
qualification, and which persists in the result” (Physics, I, 192a3I, tr. by
Hardie and Gaye), and “By matter I mean that which in itself is neither a
particular thing nor of a certain quantity nor assigned to any other of the
categories by which being is determined" (Metaphysics, Bk. VI, 1029a20,
trans. Ross).

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Act of existing (or, esse) is the principle by which ultimately a
thing is or exists.
37.

Summary of the argumentation

A. Beings that change accidentally are composed of substance
and accidents.
It is a fact of experience that at least some beings change in
some characteristics while remaining of the same nature as they
were.
But: this change is not possible unless the accidentally chang­
ing being is composed of a principle which is of itself and others
which are in the former as in a subject.
Therefore: accidentally changing being is composed of sub­
stance and accident.

B. Beings that change substantially are composed of primary
matter and substantial form.
It is a fact of experience that one kind of thing changes into
another.
But: this kind of change implies that each of the beings is com­
posed of a principle by which it is specifically what it is and a
principle which is common to both terms and receives the deter­
mining principles.
Therefore: things which undergo substantial change are com­
posed of substantial form and primary matter.
C. Individuals in the same species are composed of matter and
form.
It is a fact of experience that material tilings belong to a
limited number of kinds of things yet differ among themselves.
But: identity and difference in nature cannot flow from one and
the same principle but require two distinct principles.
Therefore : individuals in a species are composed of a prin­
ciple of specific perfection ( substantial form ) and a principle of
individuation (primary matter with quantity).

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[87-38]

D. That-whichds and the act of existing are distinct in all
limited beings.
The beings of our experience manifest themselves as subjects
having or exercising an act of existing.
The beings of our experience manifest themselves as many, and
as each limited in its being.
But: multiplicity and limitation cannot come from the same
principle which constitutes the analogical unity of beings in
their being.
Therefore: multiple and limited beings are composed of a
principle in virtue of which they are what they are (essence) and
a principle by which they are (act of existing, esse).

38. Readings

St. Thomas Aquinas, On Being and Essence, trans. Armand Maurer,
chap. 2, pp. 30-34 (on essence, matter and form, on essence and indi­
viduation); Summa Theologiae, Pt. I, q. 3, art. 2 (no matter and form
in God), art. 4 (no distinction of essence and esse in Cod), art. 6 (no
accidents in God), q. 50, art. 2 (angels are pure forms); q. 76, art. 1
(the human soul is the form of a body), art. 2 (and is individuated
by the body); On Spiritual Creatures, art. 1, ad 9 (individuals in a
species), art. 3 (is there a medium which joins form to matter?).
Etienne Gilson, Being and Some Philosophers (Toronto, Pontifical
Institute of Mediaeval Studies, 1949), pp. 169-170, 175, 184-185, on
essence and the act of existing.
J. Quentin Lauer, S.J., “Determination of Substance by Accidents in
the Pliilosophy of St. Thomas,” The Modern Schoolman, XVIII
(1941), 31-35, on substance and accident.
Jacques Maritain, Introduction to Philosophy, trans. E. I. Watkin
(New York, Sliced and Ward, 1933), pp. 217-227, 207-210, on sub­
stance and accident, matter and form.
Armand Maurer, C.S.B., “Form and Essence in the Philosophy of
St. Thomas, Mediaeval Studies, XIII (1951), 174-176; form, essence,
and the act of existing.
William A. Van Roo, S.J., “Matter as a Principle of Being,” The
Modem Schoolman, XIX (1942), 47-50; die relation of matter to form
and to the act of existing.
William M. Walton, “Being, Essence, and Existence,” Review of
Metaphysics, III (1950), 339-365.

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Selected Passages from St. Thomas Aquinas

12. Change, Matter, and Form
He says that it is necessary to posit matter in sensible substances as
substance and subject. For in every change there must be a subject com­
mon to the tenus of the change in changes which involve contraries.
For example, in change of place there is some common subject, which
now is here, and then, there. And in growth, there is a common sub­
ject, which now has this quantity, and then a smaller one (if it is a
decrease), or a larger one (if there is an increase). And in alteration
there is a subject, which now is healthy, and then sick. And since there
is also a change in substance (that is, generation and corruption),
there must be a common subject, which lies under contrary changes of
generation and corruption, and this involves the positing of terms,
which are form and privation—in this way, namely, that at one time
the matter is in act by the form, and at another time, it is the subject
of the privation of that form.
From this reasoning of Aristotle’s, it is clear that substantial genera­
tion and corruption are the principle of coming to a knowledge of
primar)' matter. For if primary matter of itself had some proper form,
by that form it would be something actual. Thus, when some other
form were brought about in addition to the former, matter would not
simply be by that form, but would become this or that modified being.
And thus there would be some kind of generation, but not generation
simply. Hence, all those who posited that the first subject was some
body—as, air or water—held that generation was the same as altera­
tion.
From this consideration it is clear how we must take the under­
standing of primary matter, for it is so related to all forms and the
privations of them, as an alterable subject is to contrary qualities.
Commentary on Aristotle’s
Metaphysics, Bk. VIII, lect.
1 (ed. Cathala, Nos. 16881689).

13. Substance and Accident as Beings by Analogy
Those things which have one predicate in common, which is not
univocal, but is predicated of them analogously, belong to the consid­
eration of one demonstrative knowledge. But being is predicated in
this way of all beings. Therefore, all beings belong to the consideration
of one knowledge which considers being as being, namely, both sub­
stance and accidents. . . .
He says, first, that being, or, that which is, is predicated in many

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ways. But we must know that something is predicated of different
things in many ways; sometimes, according to an intelligibility which
is entirely the same, and then it is said to be univocally predicated of
them, as animal of the horse and the ox. Sometimes the predicate is
predicated according to entirely different intelligibilities, and then it
is said to be predicated equivocally of them, as dog, of the star and
the animal. Sometimes the predicate is predicated according to intelli­
gibilities which are partly different and partly not different; different,
that is, inasmuch as they imply different relationships; the same, inas­
much as these different relationships are referred to some one and the
same thing. Then they are said to be predicated analogously, that is,
proportionally, according as each one, by its own relationship, is re­
ferred to that one same thing.
Secondly, we must know that that one thing to which the different
relationships are referred in analogates is one in number, and not
merely in intelligibility. . . .
Every being is called being, in relation to one first thing. This “one
first thing” ... is the subject. For some things are called being, or
are said to be, because of themselves they have esse, such as sub­
stances, which are principally and primarily called beings. But others
are called beings, because they are the passions or properties of sub­
stance, such as the per se properties of any substance. Some others are
called beings, because they are the way to substance, such as genera­
tion and motion. Still others are called beings, because they are the
corruptions of substance, for corruption is a way to nonbeing, as gen­
eration is the way to substance. And because corruption ends at priva­
tion, as generation at form, it is suitable that even the privations of
substantial form are said to be. And again, qualities or some other
accidents are called beings, because they are active or generative prin­
ciples of substance, or of such things as are related to substance ac­
cording to one of the above-mentioned relationships, or according to
any other relationship. Likewise, the negations of those things which
are referred to substance, or even of substance itself, are said to be.
Hence, we say, “not-being is not-being.” We would not say this, unless
“to be” pertained in some way to negation.
Commentary on Aristotle's
Metaphysics, Bk. IV, lect.
1 (ed. Cathala, Nos. 534536, 539).

14. Essences: Simple and Composite
The intelligible nature of quiddity or essence does not require that
it is composed or a composite. Consequently, there can be found and
understood a simple quiddity, which is not a result of the composition
of form and matter. But if we find a quiddity which is not composed

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99

of matter and form, that quiddity either is its esse, or it is not. If that
quiddity is its esse, it will perforce be the essence of God himself,
which is its esse, and it will be entirely simple. But if it is not its esse,
it is necessary that it have an esse acquired from another, as is every
created quiddity. And because this quiddity is by supposition not sub­
sisting in matter, esse will not be acquired by it in another, as is the
case with composite quiddities, but it will acquire esse in itself. And
so, this quiddity will be that which is, and its esse will be that by
which it is. And because everything which does not have a perfection
of itself is possible with regard to that perfection, such a quiddity,
since it has esse from another, will be possible with regard to that
esse and with regard to that principle from which it has esse (in which
principle no potency can be found). And thus in such a quiddity there
will be found potency and act, inasmuch as the quiddity itself is pos­
sible, and its esse is its act. This is the way I understand composition
of potency and act in Angels, and of that by which they are and that
which they are, and likewise in the soul. Hence, an Angel or the soul
can be called a quiddity, or a nature, or a simple form, inasmuch as
their quiddity is not composed of diverse principles; and yet they have
a composition of these two, that is, of quiddity and esse.
Commentary on the First Book
of the Sentences, dis. 8, q. 5,
art. 2.
15. Multiplicity in a Species
Whenever the essence of some thing is divided by the participation
[of many in it], the same essence is participated according to its in­
telligible constitution, but not according to the same act of existing.
Therefore, it is impossible for that in which essence and esse do not
differ to be divided or multiplied by an essential participation.
Commentary on the First Book
of the Sentences, dis. 2, q. 1,
art. 1, arg. 4
16. Multiplicity and Composition os. Unity
That which is simply the First can only be one, and this for three
reasons. First, from the order of the universe, whose parts are discov­
ered to lx; ordered to each other, somewhat like the parts of an animal
in the whole animal, which parts help each other. There can be no
such coordination of many things, unless they are striving for some
one end. Therefore there must be one highest and ultimate good,
which is striven for by all, and this is the principle. Secondly, this is
evident from the very nature of things. For we find in all things the
“nature” of being, in some of greater value, and in others of less. And

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yet the natures of these things are not the esse which they have. If
they were, esse would belong to the understanding of any essence, and
this is false, for the quiddity of any thing can be understood, without
understanding that it is. Therefore, it is necessary that they have esse
from some principle, and ultimately we must come to something whose
very nature is his own esse, otherwise we would have an infinite re­
gress. This is the principle which gives esse to all things, and it can
be only one, since the “nature" of being has one intelligibility' accord­
ing to an analogy. For the unity’ of what is caused requires unity' in its
per se cause, and this is the proof of Avicenna. The third reason is the
immateriality of God. For it is necessary that the cause which moves
the heavens be a power which is not in matter, as is proved in the
eighth book of the Physics. In those things which are without matter,
there can be no diversity', except inasmuch as the nature of one is
more complete and more in act than the nature of another. Therefore,
it is necessary' that that which is perfectly complete and entirely act, is
only one, from which proceeds everything that contains potency. For
act precedes potency, and the complete precedes the lessened, as is
proved in the ninth book of the Metaphysics.
Commentary on the Second
Book of the Sentences, dis. 1,
q. I, art. 1.
17. The Meaning of Being
Since in everything which is, it is possible to consider its quiddity,
by which it subsists in a determinate nature, and its esse, by which it
is said to be in act, the noun thing is given to it from its quiddity, ac­
cording to Avicenna, but the name, He Who is, or Being, from the act
of being. But since it is the case that in every' creature its essence dif­
fers from its esse, such a thing is properly named from its quiddity,
as “man” from “humanity." But in God his very act of existing is His
quiddity, and so the name which is taken from the act of existing
properly names Him, and is His proper name.
Commentary on the First Book
of the Sentences, dis. 8, q. 1,
art. 1.

CHAPTER VI

The Intrinsic Principles of Being:

II. As Analogously One
39. Comparison of the three sets of intrinsic principles

We have seen that the individual beings of our experience are
composed of various sets of principles. To sum up the results of
our preceding investigation, we can consider a being thus:
being

iact of existing
[essence

[accident
[substance

[form
[matter

If we look back at our arguments by which we discovered these
principles, we find matter and substance arc alike in this: that
each is a common subject for a different type of change, and that
essence is somewhat similar to matter and substance in that it is
the source of possibility in being itself. Hence, we can link up
these principles in a proportionate scries thus:

accident

form

esse

substance

matter

essence

Considering these principles in this relationship, we can find a
corresponding similarity in accident, form, and esse, for each of
them determines a subject, making its correlative subject to be
respectively such, this kind or species of thing, or simply to exist.
Yet there are also differences in tlic three sets of correlatives. For
example, the subject of accidents is a being in itself, whereas the
subject of form is a mere possibility of being-determined-to101

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some-essence, and essence, in turn, receives all its reality in
receiving the act of existing. Hence these three sets of principles,
being both similar and different in their relationships to each
other, are analogous to each other; and the analogy is an analogy
of proper proportionality within a being.1 But inasmuch as they
are analogous, their relationships can be summed up in a single
relationship, which is called “act and potency,” or the “actpotency correlation.”
We first discovered act and potency in the preliminary analysis
of change,2 and at that time we saw that that which changes is
first in potency and later on in act. We saw at that time that the
stages of being in potency and being in act exclude each other—
that which is in potency is not yet in act, and that which is in
act is no longer in potency. But a further analysis of change
showed us that the thing which changes is composed, and the
still more detailed analysis of change carried on in the preceding
chapter (Chapter V) showed us that the changing things of our
experience have at least a triple composition of essence and esse,
substance and accident, and matter and form. We need therefore
to learn a new and different meaning of “act” and “potency,”
a meaning which is to be developed from a much more advanced
knowledge of change.8
What is meant by “act”? We need to go back to experience and
consider what has been acquired when something has come to
be in act. For example, actual knowledge of biology is what the
biologist has when he is considering what he has previously
learned. Act is, for example, seeing as compared with the in­
activity of closed eyes; being awake as compared to the uncon­
sciousness of sleep; what the carpenter does to a piece of wood
when he is at work; the way in which a wax candle is molded as
compared to the possibility of being thus molded when it was
1 Note that we do not say, “Accident is to its esse as substance is to its
esse,” and so forth. Why we cannot do this will be clear from Chap. XII,
sec. 88.
*See above, Chap. IV.
* On the meaning of “act," see Selected Passages, No. 18.

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just a roundish lump; the billiard ball rolling as compared to its
previous state of rest; the new tissue become human in the living
body of a man as compared to the assimilability of the undi­
gested food. Thus, act may mean any sort of activity, immanent
or transient, any sort of actuality, determination, or perfection.
Hence, act is an intrinsically analogous intelligibility;4 with what
analogy', we shall see later on.
So, too, with potency as a capacity for act. Potency in itself, it
is true, is not act. But we must understand potency positively.
Take, for example, the knowledge of biology ( the information of
a certain kind, and competence in using it). A baby, a puppy,
and a doll are alike in this: that none of them know biology;
they do not have or possess the actual knowledge. But from our
experience with human beings we have found out that some
adults know biology and that all (normal) adults can learn it.
From this we infer that the baby also can learn biology. We also
know that puppies and dolls cannot. There is therefore a real dif­
ference between them and the baby: the baby has a potency to
know biology; the others do not have this potency. Now, such
a potency is something real, but it is not something which can be
discovered in itself as potency. (The potency we have been
studying here is an operative potency, a potency to perform an
operation or action. Some operative potencies can sometimes be
without their acts, but we cannot apply this to other types of
potency. )
Another type of potency is commonly called “passive potency.”
A passive potency is one which merely receives an act or perfec­
tion. For example, a piece of wood or wax is in potency to
receive another shape than the one it has now. But its potency
to receive a shape (which potency is the substance) is almost
purely passive—that is, it depends almost entirely on something
*“Act,” when used about the things of our immediate experience, is an
intelligibility, not a being or even a principle of being. There is no being
of our experience which is purely act; and each of the actuating principles
of being is some kind of act: form, esse, accident, operation. Sec also
below, sec. 74.

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[39-40]

else outside it. A thing at rest is in potency to local motion, and
this potency depends entirely on something outside itself to be
actuated. A piece of steak is in potency to become part of a living
tiling, and in this case the potency is the primary matter. This
steak can become living, not by itself but by the activity of a dog
or a man, for example. Primary matter, in itself, is a pure potency;
that is, of itself it has no act and cannot positively contribute to
the acquiring of an act. Passive potencies other than primary
matter and the capacity for local motion are passive only in­
asmuch as a subject is capable of receiving a perfection, or deter­
mination. Thus, the sense powers, the human intellect, and the
will are primarily passive.5 But they are not purely passive; they
are also principles of operation. So, too, essence is a potency for
the act of existing. We never find essences in potency—this
would be a contradiction—but always as actuated. And yet the
facts of change, limitation, and multipl icity show that essence of
itself can be and that the act of existing is precisely that by which
an individual essence is in the real order.
40. Theorems of act and potency
Thus it is clear that act and potency arc first learned in relation
to each other. As we find them in immediate experience, neither
act nor potency arc absolute designations: act is the act of a
potency; potency is the potency to some act. When we attempt
to state the relations between act and potency accurately, we
state them in exact propositions or formulas which may be called
“theorems."

1. Act and potency are distinct in their order.
The act and potency we have been talking about so far are real
act and potency, and we have already seen—in the case of sub­
stance and accident, matter and form, essence and esse—that
* It is important to note that "passivity" should be considered not merely
in relation to form or esse or efficient cause but also—and this is a funda­
mental point often overlooked—in relation to final cause (purpose, end,
goal).

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these principles arc really distinct. By a real distinction, we mean
a real absence of identity, independent of any ones considera­
tion of them. Act and potency can also be found in the logical
order: tlie subject of a proposition is potential to the predicate,
the genus to the difference. But these are considerations of the
mind and, consequently, are distinct with a distinction of reason.8
However, in one case, we raised a question: What is the proper
potency for which activity (operation, action) is the act?7 We
saw that the nature of a thing is the same as its substance, and
we understand nature as the ultimate principle of activity. But
now we must recall that from one point of view—as essence—
the substance is the potency for the act of existing. From another
point of view—as substance—the essence (in the strict sense) is
the potency for the various accidents. Ultimately, of course, the
substance—as nature—is the potency for activity. Is this third
case the same as the other two?
We must first recall certain points which we have already dis­
covered. Tlie operation or activity of any limited thing is not and
cannot be identical with the act of existing. For, (fl) transient
action affects something distinct from the agent, whereas tlie esse
of a thing is its own, and (b) immanent actions are interrupted,
whereas the esse of the thing continues throughout interruptions
and variations.8 Secondly, other accidents are modifications or
determinations of substance; they confer an added or secondary
perfection to the essence-side of being rather than to the exist­
ence-principle. Thirdly, activity is by no means tlie same as
substance and certainly is not the substantial form of a being.
•On distinctions, see above, sec. 25.
T See above, sec. 35.
’This argument is sufficient for all the beings of our immediate experi­
ence. If we wish a complete argument which would include even the
angels, who are not subject to such variations, we can take the argument of
St. Thomas, Summa Theologiae, Pt. I, q. 54, art. 3, which is based on
the intrinsic and necessary correlation of act to potency. Since activity is a
distinct kind of act, its proper potency must be a distinct one, proportioned
to the act, and this potency is precisely the accidental operative potency, or
power.

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Fourthly, activity is on the side of existence; it presupposes exist­
ence. Yet the act of existing simply cannot be considered as in
any way at all a potency, so that the act of existing could be the
potential principle which receives activity. Once a tiling is, that
is its ultimate actuality.
And yet, particularly in the case of living things, we can see
that there is a potency to act, even when an activity has been
temporarily interrupted. When, for example, wc speak of a per­
son’s ability, we are designating some principle within that per­
son, not an activity, not his substance, not his act of existing, but
rather a quality (modification, disposition) of the nature. In other
words, the proper potential principle of activity is a qualitative
accident, really distinct from the substance (as all accidents are),
and really distinct from the activity as its potential and receptive
principle. We will use the term “power” as the proper term for
an operative potency (or accidental principle of activity).

2. Act and potency are not strictly beings but principles of
being.
If act and potency were each a being, they could not be found
combined within a single being (1 being + 1 being = 2 beings).
In every order, act is that by which a being is or is some kind of
thing or exists according to some modification; and for its part
potency is that by which a thing can be or can be some kind of
a thing or can exist according to some modification. But because
act and potency are precisely principles of being, we can cor­
rectly speak of them as being, by an analogy of proportion.
This analogy, however, works out differently in the different
analogues of act and potency. The most proper sense of being is
that-which-is, or something-having-esse. The being, properly
speaking, is the whole. And only the entire thing perfectly ful­
fills the intelligibility of “that which is.” But, after the whole, and
in a derived and less perfect sense, the various principles of a
being can be called beings, to the extent and according to the
way in which they pertain to being and share in the esse of the

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107

whole. Among the secondary analogues, essence has the closest
relation to the whole, since essence is precisely that which (is).
Substance and accident are the constitutive principles by which
the essence is this essence. Substance, as we saw, is that principle
of essence by which an essence has being in itself. Within essence,
therefore, substance is the more proper subject of the act of exist­
ing. Accident is, on the other hand, by being in another ( that is,
in substance) as in a subject. According to its nature, therefore,
accident is called being inasmuch as it actually inheres in the
substance which is in itself. Yet, accident is as act to substance,
which is as potency. The substances of the things of our experi­
ence could not exist as stripped of their accidents, since in that
condition they would be indeterminate within one whole order
of essence and yet have their ultimate act, which is esse. Acci­
dent, on the contrary, is act in the order of essence, but its rela­
tion to esse is naturally indirect, that is, through substance? Mat­
ter and form are not directly beings but rather principles of
substance, which is being by proportion. By being the principles
of substance, form and matter can be called beings by a double
proportion—form, more properly, inasmuch as it is the actualizing
principle of substance; matter, less properly, or more remotely, in­
asmuch as it is capable of being actualized by form and so made
suitable to receive an act of existing. Esse, however, although it
is most truly act among all the principles of being and is precisely
that by which a being is, nevertheless, in the beings of our experi­
ence, is precisely distinguished from essence and so is not a sub­
ject of existing in those beings. Hence, in all such composite
beings the act of existing cannot be called a being even by pro­
portion. The act of existing—as a principle of being—is not that
which shares in, or is proportioned to, an act, but is precisely the
act which is shared, to which there is a proportion.
3. Act, in the order in which it is act, is unlimited in itself and
limited by the potency in which it is received.
* For the consequences of this special nature of accident, see below,
sec. 90.

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All the beings of our immediate experience are limited, and
the acts they have are likewise limited. Act, as we find it, is a
principle of being. Acts are found as perfections of some being.
They are all limited acts, correlates of some potency. Indeed, all
acts of limited beings are necessarily limited. This holds true,
whether the act in question is esse, substantial form, accidental
form, or activity. Thus, the act of understanding as it really oc­
curs is necessarily limited, as the act of this or that power, of this
or that person. The knowledge of biology for instance, as it is to
be found in any existing biologist, is limited by his particular
capacity. The act of playing a violin by even the most skilled of
violinists is in fact limited and determinate. The accident of
whiteness, as it is found in any white thing, is a particular grade
of whiteness. The circularity of any round thing is just the kind
of roundness that a material subject can have.
But none of these acts is a limitation of itself—not the act of
understanding, not the act of playing the violin, not the substan­
tial form of man, not the act of seeing. A limited act is this limited
act precisely and only because it is received in the potency or
proceeds from the potency. Any accident inhering in a substance
is limited by the nature of the substance; thus, “roundness,” as
it really exists, is limited by the nature of the substance which is
round. In the order of matter and form, we can also see the limi­
tation of act by potency. For example, a man is a man by his
substantial form, which is his soul; but human nature is never
found in its complete fullness in any existing man because the
soul, in being the act of a particular body, can actuate the po­
tency only as it is in that particular body. Similarly, in the order
of knowledge, the relationship between the absolute nature and
the individual is a relationship of limitation. What is meant by
“man" taken in itself is verified in “Peter” according to the limi­
tations of Petreity. In the judgment, “Peter is a man,” “man” is
not found according to its full perfection as absolute nature but
is limited and particularized by its reference to Peter.
In the orders of accident and substance, we have been speaking

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of the “limitation” of act by potency. To understand this more
clearly, we must recall that some accidents arc acts in one order
and potencies in another. This situation is especially verified in
the case of the powers which as accidental qualities are acts of
substances, but as powers are potencies to activity or the under­
going of activity. Take, for example, the human power to see.
The power of sight is a qualitative act and, as such, is limited by
the potency which receives it: the substance of the person who
possesses such a power. On the other hand, the power of sight is
an operative potency' which limits the act of seeing. When there­
fore we say, “Accidents are limited by the substances in which
they' are received,” we must understand “accidents inasmuch as
they are acts,” because accidents, in the order in which they are
potency (namely, in the order of operation), are themselves prin­
ciples of limitation. There is a sense in which we can say that a
potency is “unlimited”; for example, my potency' to see is un­
limited, in the sense that I can see all visible things, but my act
of seeing is limited at any particular time, in the sense that I
actually see, not all visible things but only some few. Here, the
unlimitedness of potency is precisely an imperfection, for my' be­
ing able to see is not the act of seeing at all. The unlimitedness of
my ability to see is at the opposite pole from act, for the ability' to
sec is no vision at all. This kind of unlimitedness we will call “in­
détermination." When, on the other hand, we speak of an act
being unlimited as act, we mean an unlimitedness in the sense of
completeness of perfection. For example, as an act of vision, see­
ing this white paper is entirely determinate and is completely
perfect as act of vision, but my act of seeing is in fact limited by
the capacity or ability of my eye.
There are several points which tend to interfere with the per­
fect understanding of the relationship between act and potency.
One of them is that essences seem to be limited to what they arc
by being themselves and not by any potency. For example, a
horse by' being a horse is not a cow, and so horseness by being
horseness is not cowncss. It would thus seem that essence, which

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is an act, is limited by itself. But this is a confusion. Horseness is
not limited by being horseness, for cowness is not a limitation of
horseness at all in any sense. If cowness were unreal, impossible,
and even unthinkable, horseness would not be the more perfect
for that. If we stay strictly in the order of essence, then essence is
precisely unlimited as essence; one essence is not limited by an­
other or by itself; essence is limited by individuation (horse as
horse is complete in itself; it is not lessened by “cow” but is lim­
ited in “Man of War”). The source of the confusion is that some
philosophers have failed to distinguish between being and es­
sence; they say, “A horse by being a horse is limited, for it is not
also a cow." Do they mean, “is limited as a being” or “is limited
as a horse”? It is true that a horse, by being a horse, is in a limited
way; but this is not a limitation of essence by essence but of the
act of existing by essence.
A second confusion which sometimes occurs to philosophers is
the apparent limitation of a being by its efficient cause. For ex­
ample, a pail has the potency of holding water, but how full it is
seems to depend on how much someone pours into it, and this is
a limitation by efficient cause. Two remarks are to be made about
this and all similar examples. First, what is limited in the exam­
ple is not an act but a complete being (the water or whatever
else is used as an example). Secondly, the potency in question is
not a real potency (for example, an intrinsic potency of the pail),
but it can be thought of as a property of the space (which is not
a real being). Hence, this kind of example docs not illustrate the
relationship of potency and act, for it contains neither potency
nor act but a number of beings which arc composed of potency
and act. Another sort of example sometimes used shows merely
that an efficient cause is necessary for the production of a limited
being. A line, for example, is divisible, but it is actually divided
only when an efficient cause makes a division in it. How long a
given line is to be depends on the cause which produces the line.
But note that we are dealing either with an abstract line (which
as abstract is a pure form, and so its precise length is a formal

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111

characteristic) or with a line in or on the surface of a real being.
In the former case, the line is completely perfect as a line; that is,
if it is a five-inch line, it is absolutely and completely perfect as
five-inch line, and that it is not a six-inch line is by no means a
limitation of a five-inch line. (Line, as genus, of course, is un­
limited in the sense of being indeterminate; but in that sense,
“five-inch line” doesn’t limit ‘line,” it determines it formally.)
On the other hand, if we are speaking of a line on the surface of
an existent being, the perfection of the line is limited by the
nature of the surface on which it is, and this kind of limitation
the efficient cause can do nothing about. All the examples drawn
from quantity and quantified perfection are subject to the same
confusion.
With these clarifications in mind, we can now take up the limi­
tation of the act of existing. All the beings of our experience are
limited as beings; a being as we find it is always some kind of
being. So, too, the acts of existing which pertain to limited beings
arc limited. For example, a tree exists according to the nature of
a tree; it is by an act of existing proportioned to that nature. A
man is, and he is in the way in which human nature proportion­
ately has the act of existing. Human existence, the esse of a man,
is different from the existence of any and every other kind of
being. Is the act of existing limited in and by itself? If we were to
say that it is, we would be implicitly contradicting the evidence
that the act of existing is that-by-which-a-bcing exists, simply and
absolutely. If the act of existing were limited as act, then things
could be only in that one limited way, and other kinds of existents
could not be. And so the act of existing, like all other acts, is
limited by the potency in which it is received, namely, essence.
4. Act can be known by itself, potency only through act.
This proposition does not mean that in every single case we
discover the potency through its act; it does mean that in the first
instance of any kind, we can discover potency only through act.
If we know something about explosives, we can calculate how

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strong a particular charge is without setting it off. If we already
know something about biology and chemistry, we can sometimes
predict what a particular new drug will do. But if we had never
heard of radar and knew nothing about electronics, we could not
even make an intelligent guess about what a radar set could do
if it were turned on. So, too, with living things; to find out
whether a grain of wheat is dead or alive we wait to see whether
it actually grows or not.
Ultimately, the reason why this is true is that we derive our
first knowledge of tilings from the things themselves. This means
that in the first instance things must act upon us before we know
them; things do not act inasmuch as they are in potency but in
act.10

5. Act and potency divide being in general.
The things of our experience are neither simply potency nor
simply act but composed of potency and act, and that in many
ways. In the order of existence, being is divided into potency and
act: essence and the act of existing. In this order, potency cannot
be without its act, for a thing is through its act of existing. Like­
wise, in this order, a thing either is or is not; there is no other
alternative. In the order of accident, that-which-is is divided into
substance and accident, and here, too, there is no third alterna­
tive; nor can either one of them naturally exist without the other.
In the order of substance, material substance is divided into mat­
ter and form. Between matter and form there is no third alterna­
tive; matter cannot be without any act. In the order of operation,
there is potency to act (power) and operation or activity itself.
Here, however, some powers can be without their operation. We
find habits, which are acts by comparison with the power of op­
eration itself, but potency in comparison with the operation.
41. Concluding remarks about act and potency
In connection with the order of operation or activity, there arc
* On die priority of potency to act, and act to potency, see Selected
Passages, No. 19.

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ways of speaking with which we must have some acquaintance.
There is, for instance, the term “active power.” By an active
power, we mean the power which an agent lias of influencing
something else. It is called “active” by comparison with the thing
influenced, but it is called “power” because it is not identical with
the action or operation.
Again, there is the term “virtual act,” by which we mean that
X has the power of producing Y and usually imply that X itself
docs not have the perfection of Y. For example, in logic it is said
that the premises of an argument “virtually” contain the conclu­
sion; this means that the premises bring about the conclusion, but
they do not have identically the same perfection.
Finally, there are the expressions “first act” and “second act.”
For example, if a thing has the nature or essence of man, we say
it is human in first act; when it performs the activities proper to
man, we say it is human in second act. In general, if we line up
the following factors thus:

form
(first act)

esse

accidents

activity

causality
(second act)

wc may lay down this general rule for the use of the terms “first
act” and “second act”: of any two terms in the above line, the
tenn to the left is first act relatively to the term on the right.”
In reflecting on the act-potency correlation and its various
analogates, we must be careful to keep in mind our order of ap­
proach. First, we found the distinction between substance and
accident, matter and form, essence and the act of existing. The
arguments for the distinction of substance and accident and of
11 That which is pure potency is primary matter. “Form” is very often
defined as "the first act of matter,” for matter cannot receive any other
act until it is informed; once informed, it can be, be modified, act, and
cause. Of course, this sequence of acts is not a sequence in time. Moreover,
we need not take the next tenu in th© series for our comparison of first and
second. Thus, when form is called “first act,” authors most often arc thinking
of accident or activity as “second." The scries as it is presented above is not
something which should be memorized; it is given as a key to help us read
St. Thomas and other authors who use the expressions “first act” and
“second act.”

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matter and form are very similar and are very closely connected;
nevertheless, they are, strictly speaking, independent arguments.
The distinction between essence and the act of existing is found
without any direct logical dependence upon the previous two
arguments. It is only after these sets of principles arc each dis­
tinctly known that we can see their similarity and formulate this
similarity as “the act-potency correlation.”
There are two consequences of this approach to act and po­
tency. The first is that we cannot simply deduce the existence or
distinction of these principles from any of the theorems of act and
potency. Nevertheless, we can learn a great deal about each set
of principles from our reflections on them as analogously act and
potency. One clear case is the discovery of power as an accidental
principle of operation in limited beings, which we cannot clearly
understand except by reflecting upon activity as an act and rea­
soning to its corresponding potency. Again, although each set of
constitutive principles has its own unique, independent charac­
teristics, the discovery of the analogical unity of these principles
as act and potency helps us to see the unity, the internal consist­
ency, and the harmony of being.
Secondly, act and potency are analogous conceptions. The pairs
of correlatives—matter and form, substance and accident, es­
sence and esse, and power and activity—are analogous to each
other with the analogy of proper proportionality. But, esse, ac­
tivity, accident, and substantial form are analogously act. Esse is
tlie one principle which is act without qualification, for it is the
actuality of any and all principles and the actuality of being. The
other acts are acts by proportion,12 inasmuch as they are similar
“ The analogy of proportion here is somewhat different from the other
analogies of proportion we have found to hold between the intrinsic con­
stitutive principles of being, essence, and substance. The previously found
instances (by inherence and by information) could be called "intrinsic,”
since the analogues are directly related to <• ch other and are denominated
from tire whole which they intrinsically constitute. In the analogy of pro­
portion by which esse, activity, and form are all called “act," we find an
extrinsic similarity; none of tire principles are principles of one whole
inasmuch as they are acts. Yet there is a proportion and a dependence of

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to, and yet not the same kind of act as, esse. Similarly, but in in­
verse order, primar}' matter is pure potency without qualifica­
tion. All other potencies are potencies by the analogy of propor­
tion, inasmuch as, in relation to their acts, they are determinable
and actuable in a way similar to the potency which is primary
matter.
In every' one of the analogates of potency and act, we find a
mutual correlation. Act, as we find it, is always the act of a po­
tency, and potency is that which receives, possesses, and is actu­
ated by act. But potency is always for the sake of act; potency is
ordered to act. We can by no means say’ that every' act is ordered
to its potency. Hence, act and potency are not equal principles.
Potency is an absence of act, yet at the same time it is suited to
the act which is its perfection and complement. Perhaps the inter­
locking of act and potency can be symbolized in the following
diagram, in which the italicized terms are the potencies and the
“direction” of the order is indicated by the arrow.

power

■> activity
i .esse
(being)

' ■ accident
essence

form
substance
matter

In all these cases, the order of potency to act can be expressed in
several ways. “Order” means specification, intelligibility'—po­
tency is known and defined by its act; “order” means suitability
or conformability'—potency and act “fit” each other, though with
obvious differences in the various cases.
all other acts upon esse, so that esse is the primary analogue of act. Hence,
we would call this an extrinsic analogy of proportion. However, in the order
of discovery and knowledge, activity is found first, and all other acts are
discovered through activity; see Selected Passages, No. 18. On the relation
of this analog)' and the otlicr analogies previously discovered, see below,
sec. 108.

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In the case of power and activity, a very important, special
kind of order is to be found. A striking instance of this can be
seen in beings which have knowledge. We find that men, for
example, can be in three different states with regard to some ac­
tivity. ( 1 ) They can be simply not acting in this particular way.
(2) They can be actually engaged in that activity. (3) They can
be wanting to act but not doing so for one reason or another.
This situation shows us the factor of desire or tendency. Animals
likewise have likes, desires, and so on. Plants are not only able
to grow but tend to; we truly say, for example, that their roots
“push” their way—who has not seen a cement sidewalk broken
by a tree root seeking water? We even personify nonliving things
and say that they “want” this and that, indicating that we dis­
cover in them active tendencies. Every power of operation is thus
a tendency to that operation.18 Tin's is so much the case that in
nonfree agents that do not undergo structural changes, if the
power is present and not externally impeded, the activity is also
necessarily there. The very notion of “violence," with its corre­
sponding notions of “active resistance,” “reluctance,” and so on,
testifies to the reality of tendency in things. The tendencies of
things flow from the proper nature (substance) and are deter­
mined in various ways, depending on the kind of nature and the
kind of power. We will have to consider power as active tendency
again in the two following chapters.
42. Exercise

Take the three major analogues of act and potency ( matter and
form, substance and accident, essence and esse), and apply to
them the five theorems of the act-potency correlation, pointing
out both likenesses and differences between the theorems as
stated generally and the particular analogate in question.
u In the philosophy of human nature, we find that over and above the
tendencies identified with powers of operation (called "natural tendencies”
or "natural appetitos"), beings with knowledge also have conscious tenden­
cies which are distinct powers (sometimes called "animal appetites”).

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43. Readings
St. Thomas Aquinas, Contra Gentiles, Bk. I, chap. 22 (the identity
of essence and esse in God); Bk. 11, chap. 54 (compendious summary
of act and potency in relation to the various analogues); Summa
Theologiae, Pt. I, q. 84, art. 2 (limitation of form by matter); q. 87,
art. 3 (act is known before potency); Compendium of Theology,
chap. 18, par. 1 (limitation of act by potency); On Spiritual Creatures,
art. 1 (on the nature of pure forms).
Jacques Maritain, Introduction to Philosophy, trans. E. I. Watkin
(New York, Sheed and Ward, 1933), pp. 239-256.
A. D. Sertillanges, O.P., Foundations of Thomistic Philosophy
(St. Louis, B. Herder, 1931), pp. 25-44.
William A. Van Roo, S.J., “Act and Potency,” The Modern School­
man, XVIII (1940), 1-5.
John Wild, “Tendency: The Ontological Ground of Ethics,” Journal
of Philosophy, XLIX (1952), 468-472; an excellent presentation of
tendency.
Selected Passages from St. Thomas Aquinas

18. Origin and Meaning of the Term “Act”
He shows what it is to be in act, and he says, that this word act—
which is used to signify the entelechy and perfection (that is, the
form ), and other things of a like nature, as any operations whatsoever
—is derived mainly from motion, as far as the origin of the term is
concerned. Since names are the signs of intellectual conceptions, we
first impose names on those things which we first understand, even
though they may be later according to the order of nature. But among
all the acts, motion is the best known and evident, for it is sensibly
experienced by us. And so it first of all was given the name of act,
and from motion, the term was applied to other things.
Hence, motion is not applied to things which do not exist, although
other predicates arc applied to non-existents; for we say that non­
beings are intelligible, or objects of opinion, or even desirable, but we
do not say that they are moved. Since “to be moved” means “to be in
act,” it would follow that actual non-beings would actually be, and
this is evidently false.
Commentary on Aristotle’s
Metaphysics, Bk. IX, lect. 3
(ed. Cathala, Nos. 18051806).
19. Priority of Act over Potency
Act is naturally prior to potency. And, simply speaking, it is prior
in time, for potency is not moved to act except by a being in act,

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although in one and the same subject which is at one time in potency,
at another in act, potency temporally precedes act Hence, it is clear
that form is prior rather than matter, and is also being more than
matter is, because “that by reason of which something is such, is itself
more such.” But matter does not become a being in act except by
form. Hence, it is necessary that form is being more than matter is.
Commentary on Aristotle’s
Metaphysics, Bk. VII, lect. 2
(ed. Cathala, No. 1278).
First, act is prior to potency in intelligibility. . . . That by which
another is necessarily defined, is prior to it in intelligibility, as “ani­
mal” is prior to “man,” and "subject” to “accident.” But potency can­
not be defined except by act. For the first intelligibility of the possible
consists in this, that it is suitable for it to act or to be in act, as “a
builder” is “he who can build,” and “a speculator” “one who can specu­
late,” and “the visible” is “that which can be seen," and so on. There­
fore it is necessary that the intelligibility of act precede the intelligi­
bility of potency, and the knowledge of act the knowledge of potency.
Hence, Aristotle earlier manifested potency, defining it by act; but act
he could not define by anything else, but only manifested it induc­
tively.
[Secondly] he shows how act is prior to potency in time, and how
not prior. . . . Therefore, he says first that act is prior to potency in
time, in this sense that in the same species, the agent, or the being in
act, is prior to the being in potency; but one and the same numerical
subject is in potency temporally before it is in act. . . .
After the Philosopher has shown that act is prior to potency in in­
telligibility, and in some sense in time, he shows that it is prior in
"substance” . . . that is, in perfection. ... If perfection and end did
not consist in act, there would not seern to be any difference between
a wise man . . . and a fool.
Commentary on Aristotle’s
Metaphysics, Bk. IX, lects. 7,
8 (ed. Cathala, Nos. 18461847, 1856, 1861).

CHAPTER VII

The Extrinsic Principles of Being:
I. The Agent
44. Principles of change
Change has already been considered from the point of view
of the principles within (intrinsic to) the thing which changes.
These principles we have found to be either matter and form or
substance and accident. Are these principles sufficient to bring
about a change? Or is there something outside the thing to pro­
duce the change?
In our experience, we not only find things changing but, in
very many instances, we find within direct experience factors
external to the changing thing which accomplish the change. For
example, we experience a match lighting a cigarette, ourselves
pushing an object to make it move, hitting things and being hit
by them, and so forth.
Sometimes we make mistakes in determining which agent is
the source of a particular change; for example, little children may
think that when they turn on the light switch, they are the agent
which brings about the light. The child is an agent, not directly
of the light but of the local motion of the switch. His action
closes a circuit, removes an impediment to tlie activity of the
dynamo. Such an agent which removes an impediment for an­
other agent is called an active condition1 of the effect of the sec‘Thc English word “condition” more commonly means a “passive con­
dition,” or disposition, which is in the line of material causality. The verb,
“to condition," is used both in the active sense (bring about a disposition
or qualification) and in the intransitive sense (be a disposition).
119

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[44-46]

ond agent. At other times, with regard to causes and effects out­
side ourselves, we may even confuse an occasion with a cause.
By an occasion we mean a factor that provides an opportunity for
an agent to act. In some cases, wc may not be able to distinguish
which of the factors present before an effect is the cause, and
which are the conditions and occasions; sometimes our failure to
distinguish arises from negligence or inattention on our part.
Hiere are also many situations in which we do not immediately
perceive the change as coming from an agent. For example, be­
fore the discovery that lightning is an electrical discharge, it was
popularly thought that the damage was caused by the thunder
(hence the expression “thunderbolt”). (In O. Henry’s classic
story, “The Ransom of Red Chief,” the kidnaped boy asks his
captors, “Do the trees moving make the wind blow?”)
But even if we sometimes make mistakes in determining the
agent or are unable directly to perceive the agent or sometimes
confuse an agent with a condition or even an occasion, it remains
true that sometimes we do perceive an agent bringing about a
change in some other thing. Hence, a child’s perception of his
causality can be erroneous to some extent, but his error does not
invalidate his perception and direct experience of himself causing
something.
Our immediate experience of causality, either as children in
the first instance or later on, is a direct and concrete knowledge
that a cause is working. We do not have a clear and distinct,
abstractive concept of cause, for cause and causality are not es­
sences. But even on the level of spontaneous knowledge we have
a true and certain (judgmental) knowledge of causes. In the
present chapter, wc arc trying to obtain a scientific knowledge of
causality.
As far as terms arc concerned, when we use the word "agent,”
we mean “that which brings about a change in some other
thing”; an agent is also called an "efficient cause.” The tiling
which is changed by some agent is called a “patient”; that which
is brought about in the patient is called an “effect.”

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121

45. Causal factors
In Chapter V we discussed the intrinsic principles of change »
(substance and accident, matter and form). Inasmuch as these
principles not only are necessary for the explanation of change
but also join in the coming-to-be of the effect, we can consider
these principles to be intrinsic causal factors. Substance and mat­
ter, which are both potency to change, arc called the “material
factors” or “material causes”; accident and substantial form,
which are the acts by which the being is what it is and such as it
is, are called the “formal factors” or “formal causes.” How and
in what sense can these intrinsic principles be called causal fac­
tors? Because each in its own way concurs in the coming-to-be of
the effect. The material cause has its influence in the effect by
being the subject and determinable factor in the patient, in other
words, by its self-communication to the effect as fully consti­
tuted. The formal cause has its influence in the effect by being
the act by which the effect is actually what it is, in other words,
by its self-communication as the determining and specifying
factor.
The agent is distinguished from the intrinsic principles, first,
because it is extrinsic to the patient, that is, is not a part of the
patient precisely as such, and secondly, because the precise way
in which it influences the effect is by its activity, by acting.
There is also a fourth causal factor, the goal or end (final
cause) which influences the effect by determining the agent to
act; we will consider this factor in the next chapter.
What precisely does a cause do? In general, it influences the
actual being of something; it makes something to be in act. A
cause influences the act of existing of some thing. This influence
is what we directly designate when we speak of “causality.”

46. The causality of the agent or efficient cause
Only a being-in-act can be an efficient cause. A potency, as
such, can only be a material cause; that is, it is a cause inasmuch

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[46]

as by receiving the action of a cause according to its capacity it
influences the coming-to-be of an effect. From the viewpoint of
action, a potency is a principle by which beings can be acted on.
We have seen that various principles of being can be considered
as “acts.” Can we identify the activity of causing with any of the
other acts of a being? A careful comparison of each of these acts
to causing will not only help to answer this question but will
greatly increase our understanding of causality. First, a being is
in act when it possesses substantial form, and so substantial form
is an act (correlated with primary matter). Is substantial form
the act by which immediately a being is an agent? This act is not
sufficient to make a being a cause. It is true that an efficient cause
actually must be of a certain kind or species and must be a being
in itself, but (a) substantial form is of itself the act of a matter,
and its direction is toward the internal constitution of a being,
and (b) a patient must likewise be of a certain kind and be in
itself, so that it can receive an influence. Secondly, the act of
existing is certainly an act—in a sense, it is the ultimate act even
of substances, accidents, and forms. And we can go so far as to
say that the esse of a thing is the root of all its agency—esse is
the dynamism of a thing. Is esse in a limited thing the same as
its causality? No, for the actuality or dynamism which is esse is
first and foremost an actuation of a being’s own essence. Thirdly,
the formal accidents (quality and quantity) are also acts in rela­
tion to substance, and these accidents, too, arc necessary for an
agent, but as such they arc not activity or operation itself. Tri­
directionality, expanse, shape, structure, and so on, are indeed
related to the activity of material things, as we have seen; they
condition and even determine it. These accidents, however, arc
formal causes of activity rather than acting itself.
The acting of a thing is to all the other acts of that thing as
seeing is to the eye, shining to the flashlight, running to the race­
horse, exercising magnetism to the magnet, and so on. “Acting”
is the full internal actuation of a thing; it is the activity in its full

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concrete actuality as in the agent itself. As such, it not only pre­
supposes but in a sense includes the being's actual existence.
Hence, “acting” is an analogous perfection, not only because there
are different kinds of actions but more directly and immediately
because it is an act in the order of existence.2
We can realize the unique character of acting by reflecting
that it is not an essence (a quiddity) and not simply the act of
an essence. Although being and acting cannot be separated—
except partially in the case of living things whose activity is some­
times interrupted—in the beings of our immediate experience,
esse is one actuality and activity a different and distinct one.
Hence, too, the potency to be is a distinct potency, essence;
and the power to act is a really distinct potency, power itself.
Acting is the actuation of an existing subject and its power
inasmuch as that actuation is in the agent. What is the relation
between this act and causality? For purposes of analysis, let us
consider several examples of causality. (1) Take a flashlight. It
must be a certain kind of substance; it must be structured in a
certain way; it must not be worn out; and so on. But merely from
the possession of all these acts it does not yet have the full actual­
ity of a flashlight. It exists, it has a formal structure; but as flash­
light it is still in potency. When the switch is closed, a new act
occurs. The flashlight is now shining. Is it necessarily illuminating
anything? Suppose the light ray is beamed into a vacuum. The
light continues to shine, but nothing happens to any other being.
Now, suppose an opaque object is moved into the path of the
beam. Immediately that object is illuminated; it is actually visi­
ble, and this visibility is caused by the light. (2) Take a man who
wants to be a builder. In order to do tins work he needs certain
abilities and perfections. He must know what a house looks like
and how to go about building one. He must decide what he wants
to do and, finally, he must carry out his decision by appropriate
’Note how St. Thomas explains the very notion of act itself through
activity; the text is quoted above (see Selected Passages, No. 18).

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external activity. That activity is complex, but in the last stages
it is a question of something happening to the bricks, mortar,
wood, and so on, of the house that is being built.
In these examples, and others like them, we can mentally dis­
tinguish a series of steps in efficient causality (this sequence need
not be verified in the form of really distinct steps). These dis­
tinctions will help us to understand what causality is. First of all,
the agent must be in first act. A flashlight without a bulb or with
worn-out batteries is still lacking part of its structural perfection,
and so there is no activity. Secondly, the agent must not only be
complete as a being (first act), it must be in full act as an agent.
The flashlight must be actually shining, the builder actually
building, and so on. Thirdly, the patient must be actually receiv­
ing the action—an opaque object being-illuminated, movable and
formable objects being-built, and so on. Thus, there are three
steps: a being with its tendencies, its acting, and the reception of
its influence. The same three steps can be found in other cases
of efficient causality. In the production of a marble statue there
are (1) the sculptor with his hammer and chisel; (2) the move­
ments of arm, hammer, and chisel; (3) the being-shaped of the
marble. Hence, the causality or influence or action of the agent,
considered precisely as such, is in the patient (and not in the
agent).
In the patient there is a becoming, motion, or change. Consid­
ered as received in a subject (from an agent) which changes, the
change itself is called a passion3 (that is, an undergoing or bcing• Let us recall again that potency is by its nature ordered to act. But this
by no means implies that every potency is a passive potency, for, as we have
seen in sec. 41, there are active potencies. Moreover, it is easily possible to
fall into univocation in two ways. One is to imagine that all act is form
and that all potency is the capability of being informed by the reception
of a specifying form (the basic error of historical essentialistic Aristotelianism). The second is to think that the only cause is the efficient cause and
that all passivity is toward an efficient cause (medieval nominalism made
this mistake). There is the passivity of matter toward form (and this
passivity is reception of a determination); there is the passivity of a passive
power toward its corresponding agent (and this passivity is the reception of
an influence from an agent); there is the passivity of a tendency toward

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125

affected; the abstract term is derived from the same root as the
term patient). Identically the same change, considered as coming
to the patient from the agent or cause, is the action or causality.
N.B. Distinguish efficient causality in the strict sense, as we have
been treating it here, from immanent activity. Immanent acting is the
kind of acting or operating that we find in living things: living itself,
sensing, thinking, and the like. Immanent acting is the perfection of
the being which acts, whereas transient activity or causality as such is
the perfection of the patient. Immanent acting will be treated in great
detail in the philosophy of human nature; it will be considered only
incidentally in this course.4
Moreover, a cause, in causing, does not necessarily lose any- *
*
thing. For example, a teacher does not lose any knowledge when
he teaches someone. An engineer, an inventor, a business execu­
tive, and a statesman do not lose that which they contribute;
although they expend energy, the energy is not the essential part
of the causality. It is true that an agent which is a purely mate­
rial being, in causing a purely material effect, does lose what it
gives. But that is because of the type of causality involved. If a
man gives money, he no longer has it; if he gives intelligent di­
rection, he does not lose any knowledge or intelligence.
From these two considerations, a very important conclusion
follows, (a) That which is already in full act does not intrinsically
change in becoming a cause, for the action and the change are in
the patient, (b) An agent as agent does not necessarily lose any­
thing in causing. Hence, an agent, as agent, does not undergo
change. If an agent, in our experience, does change, it does so
because it is material, because it is dependent upon other causes,
and so forth.
From the consideration of what is necessary in order that a
its goal ( and this passivity is not a reception at all—either of a form or of
an influence). These remarks are merely a warning against univocation;
they cannot be explained at tills point. They will be explained partly in the
next two chapters and partly in the treatment of the appetites in the
philosophy of human nature.
* In metaphysics, tire distinction between transient and immanent
activity is important mainly from the viewpoint of finality; see below,
sec. 56.

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[46-47]

being actually be a cause, another important conclusion can be
drawn. We have seen in Chapters V and VI that power and ac­
tivity are related to each other as potency and act. Hence, it fol­
lows that causality, which is transient action received from an
agent in a patient, and passion are identical with each other as
well as with action. Hence, the passion, which is tlie effect in the
narrowest sense of that term, is related to the operative power of
the agent as act to potency. Now, we also saw that potency and
act are proportioned to each other—a potency is specified by its
act; an act is precisely the act of some potency. Hence, between
the agent as agent and tlie patient as patient there is necessarily
a proportion or similarity. Every agent causes something like
itself.
To clarify this principle further we can temporarily suppose
that an effect as such would be simply unlike the agent as agent,
that is, neither univocally the same nor even similar in any way.
An agent acts inasmuch as it is in act, not inasmuch as it is not in
act. If the act ( passion ) produced in the patient were simply un­
like the act of the agent, then the agent would not be in act in
this particular way at all. Hence, we would have a being which
(on the supposition it is an agent) has a certain act, yet which
(on the supposition of utter unlikeness to the patient) does not
have this act. This is evidently a contradiction, and so we see
that the principle, “Every agent produces an effect like itself,” is
necessarily true.
From this we can also see that in our universe we have (a)
agents, with active powers, ordered to, and tending toward, (h)
patients, with corresponding passive capacities to be acted on and
modified. Hence, every' such agent capable of transient activity
is radically (virtually) related to, or ordered to, any and all other
beings which have the capacities to receive such activity'.
47. Types of agents: univocal and equivocal causes

Tlie kinds of agents we find in our experience depend upon
other agents for both their being and their causality'. When we

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want to express the dependence of an agent upon other agents,
we call it a secondary cause. In contrast, an agent which does not
depend upon other agents is called a first cause? One special
aspect of tlie dependence of a secondary cause upon other causes
is that it presupposes a pre-existing patient; in our experience,
there must be something for a secondary cause to work on before
causality can take place. Consequently, the causal influence of a
secondary cause upon the act of existing of another being (pa­
tient) does not consist in making something to be where nothing
was before (in causing a transition from not-being simply to
being) but in bringing about a transition from one kind of thing
to another. Hence, we say that a secondary cause does not cause
being simply but causes some kind of being. There is a further
consequence of this: no thing in our experience is totally de­
pendent upon a single agent. For an effect is dependent upon a
cause only in so far as the cause is a cause. For example, a builder
is the cause of the coming-to-be of a house, and, conversely, tlie
house is dependent upon the builder for its becoming. But when
this coming-to-be has reached its term, and the house is (exists)
as a finished thing, it does not depend upon the builder for its
being. The builder therefore is not the cause of the being of tlie
house except indirectly as the cause of its becoming?
A second and rather easy distinction to make is based on the
kind of similarity between the cause and effect.7 Some causes and
effects are exactly of the same nature. We can see this very
clearly in the ordinary' generation of living things: parent and
offspring are of the same species. Similarly, the heat in the heater
and in tlie tiling heated are exactly the same kind of perfection.
Any cause which has strictly the same kind of perfection as the
effect is called a “univocal” cause. Sometimes, however, the per­
fection in the cause is not of the same kind as the perfection it
“ As we shall see later, in Chapter IX, there is only one First Cause, which
is Cod.
•As a completed being, the house depends on other causes for its being:
the substances out of which it is made, its structure, tlie earth, and so on.
’See Selected Passages, No. 20.

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brings about. At times, the cause is only a mediate cause. For
examples, we can take the remote general causes of particular
effects, such as atmospheric pressure, gravitation, sunlight in re­
lation to growth, and so on. Here, the unlikeness between the
(remote) cause and its effect is largely due to the proximate
causes which are between the remote cause and the ultimate ef­
fect. Such causes, which are not univocal because they are not
the immediate causes of their effects, we shall call “equivocal
causes.” 8 Some causes, on the other hand, are somewhat unlike
their effects because they act through knowledge: the bird is not
identical in nature with its nest, the man is not of the same na­
ture as the machine or the art work which he produces. A cause,
which is somewhat unlike its effect because it causes through
knowledge and not simply through nature, we shall call an
“analogous cause.” The kind of analog}’ which is in question
between an analogous cause and its effect shall be investigated
below.

48. Types of agents: principal and instrumental causes

If I write abc, the fact that these are letters is due to me and
not the pen. The power of the pen is to make ink marks when ap­
plied to paper, but the power to make letters is in me and not
in the pen. Thus, we can distinguish two powers in the instru­
mental cause which are really distinct; the natural power which
the instrument has of itself ( a saw has power to cut, a typewriter
to type, and so on), and the instrumental power which the in­
strument has from the principal agent.
There are two powers, but not two actions. In the workingtogether of principal and instrumental causes, for example, the
writing of a letter, there is only one action and only one effect
which is due to two causal factors. We can make a distinction
of reason between the natural action of the instrument and the
* Most authors use the terms, "equivocal,” "analogical," and “analogous,”
as equivalent terms when they speak of causes. St. Thomas uses the
various terms indifferently. We have chosen to make a distinction in order
to handle the cases more clearly.

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instrumental action; or, in the effect, we can make a distinction
of reason between what is due to the instrument as a natural
being and what is due to the instrument as instrument.
We can consider the relation of principal cause to the instru­
ment from the part of each one of them. The instrument limits
and particularizes the action of the principal cause; thus I get
different effects with a pen, a pencil, a brush. On the other hand,
the instrument as such is not active of itself; it is caused to
be a cause, it is “moved” by the principal cause to produce an
effect.
N.B. Distinguish between an instrument in the strict sense which is
moved to cause by the principal cause and the instrumental use or
application of a natural cause. Compare the instrumentality of an en­
graver in using a tool and in using an acid to engrave a name on a
piece of metal. A chemist, in producing synthetics, uses some instru­
ments and also makes instrumental applications of the proper natural
effects of chemicals.

There can be wide variation in the principal-instrumental rela­
tion. Compare the relationship of a man with a pen to the work
produced and that of a man to the electrical calculator he uses.
Many modern machines are extremely elaborate, and the nature
of the effect is largely determined by the natural materials and
the artificial structure of the machine: for example, the push­
button machine which turns out automobile frames.
Hiere is a similarity between the conception, “instrumental
cause,” and the conception, “secondary cause.” y In both there is
a dependence upon another cause (or causes). The instrument,
to the extent that it is merely an instrument, is a cause only inas­
much as it receives and transmits the causality of the principal
cause. The only evident example of such a purely passive instru­
ment is in the area of local motion. For example, when a person
uses a stick to push a stone, the causality of the stick is purely
received; it moves the stone only to the extent that it itself is
caused to move the stone. In the relationship of the principal to
•Seo Selected Passages, No. 21.

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the instrumental cause we find this distinguishing trait: that the
very causing of the instrument is received, not as a nature, not as
a permanent possession (that is, by way of an inherent form),
but as an essentially transient influence. The secondary cause,
on the contrary, although it does depend on other causes so that
without them it cannot cause, has a causality all its own and has
a proper and positive influence. A secondary cause may need the
co-operation of other causes; it may be moved to action by some
other cause. But when it is moved to action, its causality is at
least partly its own, an active expression of its own nature—
although not exclusively so.
49. The exemplar cause
An intelligent agent engaged in the production of something
has a more or less perfect knowledge of the thing he intends to
make and directs his activity according to that knowledge. The
object as known, according to which he directs activity, is called
an “exemplar.” (A man may use an external model, as when a
painter has a bowl of fruit in front of him which he is copying,
but the external model is not directly a cause; it has influence
only in so far as it is known.) An exemplar is a true cause be­
cause it does have an influence upon the being of the effect—not
immediately but through the agent.
The type of causality' of an exemplar is like that of form; that
is, it specifies the effect. But instead of being the form of the ef­
fect directly and of itself, it is the form of the (intelligent) effi­
cient cause. For this reason, the exemplar cause is sometimes
called an “extrinsic formal cause.”

50. The theorem of causality10

So far we have been considering tire causality which we di­
rectly experience, that is, where we experience both the coming“Most authors call this the "principle of causality.” Most of them then
proceed to say that it is “self-evident” from the very analysis of the con­
cepts or that it is deduced from the principle of sufficient reason, and so
fortli. These implications are historically attached to the term, “the principle

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to-be of the patient and the activity of the agent. In still other
words, we understand that some things as a matter of fact come
to be in dependence upon an agent. Or again, we understand
that some things pass from potency to act under the influence of
an agent which is in act.
Now the question arises: Is this necessarily so? In other words,
can something comc-to-be, pass from potency to act, without the/^
influence of any agent in act? As far as our everyday knowledge
is concerned, we know that every case of coming-to-be has an
efficient cause somewhere or other—things don’t just happen. So,
too, the whole of science proceeds on the implicit understanding
that events and things have causes which determine them to be
and that with sufficient patience, skill, and instruments, these
causes can be discovered. But our question is: Is this implicit
knowledge correct?
DIGRESSION ON NECESSITY

In general, that is necessary which cannot not-be. Necessity is
the condition, state, or characteristic of a thing according to
which it must be as it is and cannot not-be. Necessity is of various
kinds: existential (if an existent cannot ñot-exist) or essential (if
something must be as it is); intrinsic (if the necessity is rooted
in the necessary being itself) or extrinsic (due to some other
being).11*
1
of causality,” and so this text avoids using it. What we are talking about
is a proposition of a very general and inclusive character, whose truth can
be established beyond doubt. Such a proposition is called a "principle,"
"law,” or "theorem.” On the nature and treatment of causality in its general
formulations, see Joseph Owens, C.Ss.R., "The Causal Proposition,” The r
Modern Schoolman, XXXII (1955).
“ For convenience’s sake, we will list some of the types of necessity, try­
ing to point out the bases on which the various divisions are made.
Necessities are:
(1) based on the source of the necessity, intrinsic (for example, acid
necessarily reacts with certain metals) or extrinsic (a pencil moves
necessarily as long as I, an efficient cause, am moving it).
(2) based on the scope of the necessity, absolute (under all conditions,
a triangle must have three sides) or relative (exercise is necessary for a
growing boy, but he can live without it).
(3) based on temporal or causal priority or posteriority in relation to

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The opposite of necessity' is contingence, the possibility' of un­
dergoing change, of being and not-bcing, and so forth. Note that
necessity and contingence are not so opposed that a thing is either
completely necessary or completely contingent. No thing is so
completely' contingent that there arc no necessities about it—the
most contingent of beings and events has at least consequent
necessity (now that it is, it cannot not-have-been) and some es­
sential necessities (being what it is, while it is, it cannot not-be).
On the other hand, though necessity as necessity is not contin­
gent, there are some particular contingent necessities. For exam­
ple, the necessity by which a nonfree agent acts is contingent
upon its continued existence, the co-operation of other causes,
and the like; something which is necessary with consequent ne­
cessity is contingent with regard to its antecedents; the essential
necessities of limited beings are existentially contingent (for ex­
ample, if a man is to be, he must be rational, he must possess an
intellect and a will). The concrete copresence of both necessity
and contingence in the same being is a point of great importance
for this reason among others, that it shows how we can begin a
necessary, demonstrative knowledge from contingent things.
BECOMING, CONTINGENCE, AND LIMITATION IN

RELATION TO CAUSALITY

Now, our question is: “Can something come-to-be without any'
agent?” Note that something which comes-to-be does not have
before its becoming the perfection which it later acquires but is
only in potency' to it. Potency is ordered to act; but it is also and
the thing which is necessary, antecedent, or de jure ( die actions of non­
free agents are antecedently necessary because they flow from die nature
which is causally prior to action) or consequent, or de facto (once Socrates
is sitting, he sits necessarily [in virtue of the principle of contradiction]).
(4) based on the object of the necessity, logical (if the premises are
true and correct, the conclusion must follow) or real (tiiis event must come
about if its necessary causes are actual).
(5) based on the objects of real necessity, essential (the essence of man
necessarily makes him rational) or existential (God, Whose essence is
identical with His act of existing, exists necessarily) or operational (any
nonfrec agent, like a dog or a chemical, necessarily performs its operations ).

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by its very nature distinct from act. It is not-act. To suppose that
a being in potency can of itself acquire the act corresponding to
that potency12 is implicitly to deny any significant difference be­
tween potency and act; it is to suppose that potency is a kind of
hidden act. But this is not true and not even really intelligible;
it is an implicit contradiction. If potency is not the same as act,
then any transition from potency to act takes place under the
’iniliicnce.oLan agent in act. From these considerations we derive
our first general statement about causality: Any tiling which
comes-to-be—which passes from potency to act—does so under
the influence of an agent. This statement of causal dependence
is first discovered in immediate experience and is known to be
true without exception by an analysis of the beings themselves
and their intrinsic constitution. Such a proposition, which de- j
pends on no outside evidence except on the intrinsic intelligibility^ )
of the being about which it is said, can be called “self-evident,” j <
or “per se known." 1:1
/
Every tiling which comes to be is existentially contingent; that
is, of its nature or essence it is such that it can exist or not-exist.
Hence, we can extend our question about causality to include
those things about whose temporal origin we are ignorant. Let
us suppose a being about which all we know is (a) tliat it does
exist (for example, a pure spirit, or angel), and (b) that it is a
“Living things are said to “move themselves” (that is, from potency to
act). This is by no means contrary to the causal dependence of things
which change; for the living thing is not entirely in potency—it has its
substantial act and its operative powers; moreover, many distinct causes
(moisture, food, sunlight, and so forth) are necessary so that the living
thing can continue to five and grow. See also, Selected Passages, No. 20,
par. 1.
“ Please note how flic term, "self-evident,” has been defined. Students
sometimes think that "self-evident” means "evident to itself’; sometimes
they think that a self-evident proposition is one that is explicitly known
and admitted by all men—babies, barbarians, people who have never
thought about it, and so on.
Philosophers have historically used the term "self-evident” in other senses;
often, they have said tliat a self-evident proposition is known to be cer­
tain from an analysis of the concepts (and even of the terms!). There are
some propositions which are known from an analysis of their concepts; the
causal proposition is not one of them.

,
•.<
I
¡

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limited being. A limited being is a limited actuality. We have
seen that an act is not limited of itself as act but can only be
limited by a potency distinct from it by which it is limited.
Hence, that which is limited as a being is composed of two
really distinct principles in the order of being itself, namely,
essence and the act of existing.
We can make some definite statements about the relation be­
tween essence and the act of existing in a being in which these
principles are really distinct. First of all, since the act of existing
is not a quiddity or form, it can never be a part of an essence.
Secondly, esse cannot be the property of any essence. A property
is an accident which inheres in a substance, is necessarily con­
nected with that substance, and is a natural and necessary con­
sequence thereof, as risibility is a natural and necessary conse­
quence of the essence of man. Now, that which is a consequence
of an essence is caused by that essence and is posterior to it in
nature. For to be a cause, a thing must first exist in itself. An es­
sence which is really distinct from its act of existing exists only
by the possession of that act of existing. And the act of existing,
inasmuch as it is an act, is prior in nature to its correlative po­
tency. To suppose that esse is the property of an essence really
distinct from it therefore involves a contradiction. Such an es­
sence would be both prior and posterior to its own esse and
would have to exist before it existed—it would have to exist in
order to be a cause of esse; and tins would be before it existed,
since it is by its act of existing that a tiling is. Therefore, in a
limited being, cssc cannot be a property of the essence.
Two statements can therefore be made about the esse of a
f limited tiling. First, esse is not the essence or a part of the essence
2 of a limited thing. Secondly, esse is not a property of the essence
of a limited tiling.14 But esse is related to such an essence; this
“ Compare the statement of Bertrand Russell: “There does not even seem
any logical necessity why there should be even one individual—why, in fact,
there should he any world at all’’ ( Introduction to Mathematical Philosophi/
[London, 1924], p. 203).

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relation is one of non-necessary, or contingent, possession. Esse is
possessed as an act and, therefore, as prior to its receptive subject.
Yet it is prior in such a way as not to be a thing in itself, nor to
have the essence as its property or possession. The essence, al­
though it is posterior to the esse, is necessarily the subject of that
act. Hence, the esse, even as prior and as act, cannot be inde­
pendent. It depends on something other than itself. The “some­
thing other” cannot be the essence of the limited thing itself, as
we have just seen. Hence, in order that a limited being can be,
it must depend on a cause. Hence, ever}' limited being is existen­
tially contingent, and every existentially contingent being de­
pends on a cause.
This statement of causal dependence is a very inclusive state­
ment. It includes and goes beyond the first statement of causal
dependence, and it is proved true by a reasoning process based
on act and potency and the analysis of an essence really distinct
from its act of existing. Hence, this proposition may appropriately
be called a “theorem.”

51. The analogy of eminence in causality
In considering the types of efficient causality, we noted that
there are both univocal and nonunivocal causes. Univocal causes
belong to the same species as their effects, whereas nonunivocal
causes do not. Nonunivocal causes are in some way unlike their
effects.
We have also seen that a cause must be in some way like its
effect. If a cause were totally unlike its effect, that cause would
be acting according to some way in which it is not in act—and
this would be contrary to the nature of an agent as it manifests
itself: an agent acts inasmuch as it is itself in act. Hence, the non­
univocal cause can be truly denominated from the perfection of
which it is the cause. Since the cause does not possess the caused
perfection univocally, it must possess either a different but equiv-

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alent perfection” or a perfection which somehow includes the
caused perfection though it is greater. In the former case, the
analogy will be said to be “extrinsic”; in the latter, “intrinsic.” For
example, the food which conserves the health of an animal is truly
called “healthy.” But health, properly speaking, is a quality of a
living tiling; it can be the intrinsic modification only of a living
thing. Therefore, the food—for example, a broiled steak—is not
intrinsically healthy; yet it does have a relation to the health of a
living man. For an example of intrinsic analogy, consider a bird
building a nest. Ilie bird does not have as its own intrinsic per­
fection the shape and structure which it gives to its effect, and so
it must have some other perfection. We know that birds are be­
ings capable of knowledge, and so we can see that the perfection,
“having sensitive knowledge of a nest,” is intrinsic to the bird. A
man, inventing a marvelously complicated machine, and not be­
ing such a machine by nature, must possess a similar perfection
through which he can bring about the perfection in the patient
upon which he acts. This perfection is intellectual knowledge,
which includes in some way the perfection of what is known.
Hence, we can truly and intrinsically speak of a “powerful idea,”
a “mighty conception,” and so on. Conversely, we can call the
effect by the perfection of the cause, and tliis is usually an ex­
trinsic analogy; for example, we speak of a “clever gadget.”
We have seen earlier” that there are two kinds of nonunivocal
causes: analogous and equivocal. If we consider the two kinds of
eminence in causality—intrinsic and extrinsic—we can see a cor“ Electrical energy is equivalent to local motion, and an electric motor is
precisely a machine for converting one kind of energy into another. Again,
photosynthesis in plants turns solar energy into the locked-up energy of
chemical combination. For another example—good meat contains such a
mixture of chemical compounds that the animal which feeds on it can
maintain itself in good health. For still another example: the two parents of
a plant hybrid together contain the equivalent of the perfection of the
hybrid offspring: polyploidy in plants can be brought about by the normal
processes of cell division interfered with by high energy rays; the rays
together with the normal processes of the parent cell are equivalent to the
peculiar structure of the new cell.
* See above, sec. 47.

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respondent» between the kinds of causes and the kinds of causal­
ity. An analogous cause acts through knowledge and so need not
have a nature univocally the same as its effect; nevertheless the
knowledge is intrinsic to the cause and shows a nature more per­
fect than the nature of the effect. An equivocal cause acts by
nature; it is a remote cause, and so its effect need not be of the
same nature, since the nature of the effect may be determined by
a proximate cause. The equivocal cause truly causes and so can
truly be denominated from the effect, but the denominated na­
ture is extrinsic to the cause.
Both kinds of eminence in causality are similar in this: that the
basis of the “community” between cause and effect is causal in­
fluence and causal dependence. Hence, this analogy of eminence
is more like the analogy of proportion than the analogy of pro­
portionality.1 T It is a single relationship of two terms, not a similar­
ity of two proportions between two sets of terms. We can distin­
guish intrinsic analogy of eminence from the extrinsic by seeing
whether the perfection of the cause is different and equivalent
or similar and inclusive and therefore greater and intrinsic. Note
that this distinction rests on some kind of knowledge of the cause
in itself and its intrinsic perfections. If we merely know that X
is the cause of some perfection and is a nonunivocal cause, we are
unable to tell whether it is an equivocal or an analogous cause,
and, consequently, wc do not know whether the analogy is in­
trinsic or extrinsic.
52. Definitions

Active condition is that which removes a hindrance that pre­
vents another agent from acting. (For example, an agent who
opens a shutter is a condition of the sun’s illumination of the
room. )
Passive condition, or disposition, is a state or modification of a
” See Selected Passages, No. 22.
For a comparison and classification of the various kinds of analogy, sec
below, sec. 108.

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patient influencing an activity after the manner of a material
cause. (For example, the general run-down condition of a sick
person can influence the way in which the action of a medicine
is received.)
Occasion is that which provides an opportunity for an agent’s
action without acting itself. (For example, an anniversary' cele­
bration may be the occasion of a man’s getting drunk. )
Cause is that which influences the act of existing of some thing.
Agent (or efficient cause) is that which by its activity influ­
ences the being of another. (For example, a sculptor)
Patient is that which is affected or being changed by another.
(For example, marble)
Effect is that which is brought about by a cause. ( For example,
the statue)
Acting is the full intrinsic actuality of an operative power. (It
is therefore a concrete, existential, and analogous act. )
Action ( in the strict sense ) is the change produced in a patient,
considered as received from the agent. ( For example, the taking­
shape of the statue as brought about by the sculptor. )
Transient action is a more explicit term for action in the strict
sense.
Passion is the change received from an agent, considered as
taking place in the patient. ( For example, the taking-shape of a
statue under the influence of a sculptor, considered as a modifica­
tion of the statue.)
Causality is the influence of the cause upon the effect.
Formal cause is the intrinsic principle of being which influ­
ences the being of the effect by communication of itself to the
effect as the determining or specifying act. ( For example, the soul
of a living thing.)
Material cause is the intrinsic principle of being which influ­
ences the being of the effect by communication of itself to the
effect as the subject and determinable, limiting factor. ( For ex­
ample, the body of a living thing. )
Efficient cause (or agent) is the extrinsic principle of being

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which influences the being of the effect by its activity. (This is a
more formal definition.)
A secondary cause is one which depends upon one or more
causes for its being and its activity.
First cause is one which does not depend on other causes for
its being or its activity.
Principal cause is a cause which acts by its own power and is a
source of causality. (N.B. This does not exclude the possibility
that a principal cause may be previously caused by another.)
Instrumental cause or instrument is a cause which acts by the
power of the principal cause and only to the extent that it is
moved by the principal cause.
An exemplar is an object known by an intelligent cause, accord­
ing to which that intelligent cause directs his activity.
Necessity is that condition or qualification of a being by which
it is (or is what it is) and cannot not-be.
Existential necessity is the necessity by which a being which is
cannot not-be.
Essential necessity is the necessity by which a being is what
it is.
Absolute essential necessity is the necessity by which it is sim­
ply impossible that a being be otherwise than it is, and is based
on the real identity of an essence with itself.
Relative essential necessity (physical or natural necessity) is
the necessity by which distinct properties or activities arc linked
to the essence from which they flow and is based on formal caus­
ality.
Contingence is the condition or qualification of a being by
which it can be otherwise than it is.
Univocal cause is one which belongs to the same species as its
effect. (For example, a heater and the thing heated)
Analogous cause (in the strict sense) is one which does not
belong to the same species as its effect but intrinsically possesses
a perfection which includes and goes beyond the perfection of its
effect. (For example, a man, possessing intellectual knowledge

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[the greater and more inclusive perfection] causes a structure in
a collection of material things [a perfection of a different kind]).
(In the wide sense, analogous cause and equivocal cause are
used interchangeably. )
Equivocal cause (in the strict sense) is one which does not
belong to the same species as its effect but possesses a different
and equivalent perfection. (Healthy food, as cause of the health
of an animal )
Analogy of eminence in causality is an analogy based on causal
dependence of an effect on its nonunivocal cause, involving a true
attribution of the perfection of the effect to the cause, in a higher,
greater, or "eminent’’ sense. The analogy' is intrinsic if the cause
is strictly analogous; extrinsic, if the cause is equivocal. (Con­
versely, the perfection of the cause can be truly attributed to the
effect in an imperfect or lesser sense, and this perfection, too, can
be either intrinsic or extrinsic. )
53. Proofs (to be developed)

A. Whatever comes to be has a cause.
B. Whatever exists contingently has a cause.
C. No effect can be greater than its total cause.
54. Readings

St. Thomas Aquinas, Contra Gentiles, Bk. II, chap. 21 (proportion
between cause and effect); Bk. Ill, chap. 21 (tendency), chap. 69
(that creatures are truly causes of esse); Summa Theologiae, Pt. Ill,
q. 19, art. 1, par. 2 (distinction between instrument and instrumental
use of a natural cause), q. 62, art. 1, last par. (distinction between
principal and instrumental cause); Pt. I, q. 54, arts. 1-3 (a very
*
im­
portant series of texts on being, substance, esse, acting, and power),
q. 104, art. 1 (a difficult but very important text on the difference
between the cause of coming-to-be and the cause of being).
Aristotle, Metaphysics, Bk. IV, chaps. 1-2, 1013a-1014a24 (on
principles and causes).
Francis L. Hannon, Principles of Psychology, rev. ed. (Milwaukee,
Bruce, 1951), pp. 202-204; a brief summary' of the work of Michotte
on the perception of causality.

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Robert O. Johann, S.J., “A Comment on Secondary Causality,” The
Modem Schoolman, XXV (1947), 19-25.
John Wild, “A Realistic Defense of Causal Efficacy,” Review of
Metaphysics, II (1949), 1-14.
Selected Passages from St. Thomas Aquinas

20. Kinds of Agents and Patients
Those artifacts which have such a nature [that is, one to lie pro­
duced by art], as stones are the matter of a house, cannot be changed
by themselves, for it is impossible that they be changed except by
another. And this principle is true, not only in artifacts, but in natural
things. For in this way the matter of fire cannot be changed to fire
except by another. And hence it is that the form of fire is not generated
except by another. . . .
Hence, it must be said that only living things are found to move
themselves locally, but other things are moved by an exterior principle,
either that which generates them, or that which removes a preventing
condition, as is said in the eighth book of the Physics; so, too, only
living things are found to change themselves according to the other
kinds of change. This is because they are found to have different parts,
one of which can be the agent, and the other the patient, and this is
the situation which obtains in everything which moves itself, as is
proved in the eighth book of the Physics. . . .
It is about such matter having in itself an active principle that the
Philosopher is speaking here, and not about inanimate things. This is
clear from the fact that he compares the matter of fire to the matter
of a house in this regard, that both are moved to the form by an ex­
trinsic agent. Yet it docs not follow that the generation of inanimate
tilings is not natural. For it is not necessary for natural change, that
the principle of motion in that which is moved be an active and formal
principle; sometimes it is passive and material. . . .
He had said above that everything which is generated is generated
by something like it in species. But this is not the same in all cases,
and so he intends here to show how this is found in different cases.
. . . Everything which is generated from something, is generated
from it per se, or per accidens. But what is generated from another
per accidens, is not generated from it according as it is such as it is,
and so it is not necessary that in the generator there is the likeness of
that which is generated. Thus, the finding of a treasure has no like­
ness in him who, digging in order to plant, finds the treasure acciden­
tally. But the per se generator, generates such as it itself is, as a gen­
erator. And so it is necessary that in a per se generator the likeness of
the generated must be in some way.
But this comes about in three ways. In one way, the form of the

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generated pre-exists in the generator according to the same way of
being, and in similar matter, as fire generates fire, or man generates a
man. This is wholly univocal generation.
In another way, the form of the generated pre-exists in the genera­
tor, not according to the same way of being, nor in a substance of the
same kind. Thus, the form of the house pre-exists in the builder, not
according to its material mode of being, but according to an immaterial
mode of being, which it has in the mind of the builder, but not in the
stones and wood. This generation is partly univocal, as far as the form
is concerned, partly equivocal, as far as the mode of being of the form
in the subject is concerned.
In the third way, the whole form of the generated does not pre-exist
in the generator, but some "part" of it, or some part of a part, as in hot
medicine there pre-exists the warmth which is a part of health, or is
something leading to a part of health. And this generation is in no
way univocal.
Commentary on Aristotle’s
Metaphysics, Bk. VII, lect. 8
(ed. Cathala, Nos. 1440,
1442e, 1442z, 1444-1446).
21. Difference between Principal and Instrumental Causes

For a principal agent acts according to the requirements of its own
form, and so the active power in it is some form or quality having com­
plete reality according to its own nature. But an instrument acts inas­
much as it is moved by another. Hence, it has a power proportioned to
this motion. But motion is not a complete being, but it is a way to
being, as it were something between pure potency and pure act, as is
said in the third book of the Physics. And so the power of an instru­
ment inasmuch as it is an instrument, according as it acts to produce
an effect beyond that which is proportioned to it according to its na­
ture, is not a complete reality having a fixed being in its nature, but
an incomplete reality (like the power of affecting sight which is in the
air inasmuch as it is an instrument moved by an exterior visible thing).

Commentary on the Fourth
Book of the Sentences, dis. 1,
q. 1, art. 4, qa. 1.
22. Analogy of Proportion Compared to the
Analogy of Eminence in Causality

The creator and the creature are reduced to one, with a community,
not of univocation, but of analogy. This latter community can be of
two kinds. It can consist in this, that several things participate in one

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thing according to priority and posteriority, as potency and act par­
ticipate in being, and, similarly, substance and accident. Or this com­
munity can consist in this, that one receives its esse and its essence
from the other, and this is the analog}’ of the creature to the creator.
For the creature docs not have an act of existing except inasmuch as
it has come from the First Being; consequently, it is not called being
except inasmuch as it imitates the First Being.
Commentary on the First Book
of the Sentences, prologue, q.
1, art. 2, ad 2.

CHAPTER VIII

The Extrinsic Principles of Being:
IL The Goal of Action
55. The goal of action

So far, in our analysis of change and being, we have considered
the material, formal, and efficient causes of becoming and being.
Are these three causal factors sufficient? Or, at least in some cases,
is it still possible and meaningful to ask, “Why?” For example,
when we know who did this, what he did, and to whom he did it,
are we satisfied that we fully understand the action? When we
ask, “Why?” do we not want to find out the reason or cause,
which is, in the context, the purpose or motive of the action? In
other words, when we have found material, formal, and efficient
causes, we still have not discovered the full intelligibility of
action and causality.
An inspection of various kinds of beings shows us that they
have various kinds of activity; they arc either conscious beings or
beings without knowledge. We will consider each kind in turn.
A.

ACTIONS WHOSE RESULTS ARE FORESEEN AND DESIRED

In the case of our own activities, we find that we often know,
or at least think we know, the results of our transient actions.
What is more important, we find ourselves wanting, desiring,
choosing these results either for themselves or as a means to some­
thing else, and so we go on to perform those actions. For ex­
ample, a man may want the money he can earn by his work, or
he may want the product itself. In the former case, we speak of
"the end of the agent”; in the latter, of “the end of the activity
144

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(or work)”—though the latter is also desired as an end by the
agent. In both cases, the end is foreseen and desired by the
agent.
We also often foresee and want our own vital activities for
their own sake. For example, a student may want to know some­
thing, and the knowledge itself is the end which he foresees and
desires. Again, a man may want to travel in order to see and ex­
perience for himself the scenes or the customs of different coun­
tries. In these cases, the action itself is an end which is foreseen
and desired.
An end which is foreseen and desired is called a "purpose.”
A purpose is a real cause of action, for it influences the coming
to be of something, either a product or an immanent activity. A
purpose is by no means an efficient cause; it does not act. People
sometimes think that an efficient cause pushes an object, and a
final cause “attracts” or “pulls” it. Pulling is as much an efficiency
as pushing, but we have to use some words to express the
causality of a purpose, and these words are applied to purpose
by an analogy with efficient causes. So, when we say that “A
purpose moves an agent, or directs or influences him,” we are
understanding this of an influence which is not an efficiency. A
purpose, then, causes by directing an agent to make actual that
which is preconceived and desired. This direction to a goal wc
call “finalization.” An intellectually knowing agent is finalized by
the knowledge it has of a goal (or end) to be made or gained.1
In the activities of brute animals, there is also some evidence
of some foreknowledge and desire of ends. Certainly, we do not
have the same kind of evidence that we find in ourselves. But
there is some; a hungry dog, for example, goes hunting for food.
The dog does not know that it has a purpose as such; it only
knows that it is hungry, that food will satisfy that hunger, and
1 An end that is to be made is, for example, a picture to be painted, a
house to be built. An end that is to be gained is, for example, a house or a
field or an automobile to be acquired. In the second case, the end already
exists, but not as possessed by the agent, and it is as an end to be possessed
that it moves the agent to act.

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that food can be found by looking for it. When we want to know
why a particular dog is hunting, we are satisfied when we know
that it is looking for food. ( In saying this, we are intellcctualizing
the brute’s activity; the brute doesn’t think of an end; it imagines
and desires food, and we understand that this foreknowledge of
food is as a matter of fact a knowledge of an end.) The brute’s
activity of hunting is finalized by its knowledge of the sensible
object. This sensible object is not known precisely as end, but it
is known concretely and in the particular as something to be
gained or avoided. Hence, we can speak also of the purposive
activity of animals. A sensitively knowing agent is finalized by
the knowledge it has of a sensible object (which is a goal) to be
gained or avoided.
What exactly is the function of a purpose, that is, a consciously
held goal? We want to know this, because from an analysis of
our own purposive activity we can understand what is meant by
the terms, “end," “goal,” “final cause." A purpose is obviously
not one of the intrinsic causes or principles of our being, like
matter and form or essence and tlie act of existing. First and fore­
most, a purpose is concerned with activity. How does purpose
function in connection with activity? It is clearly not another
efficient cause, for a known goal, as such, is not a real being and
so has no activity in the strict sense of that word. We can see
still more clearly the function of purpose if we compare it with
an exemplar cause. The exemplar causes by way of specifying
some type of activity, but only conditionally; that is, if there is to
be activity', it will be of such-and-such kind, as specified by the
exemplar. But a purpose, as such, “moves” the agent to act; it is
a determinant of action simply, and only secondarily of action of
this or that kind. It functions as tlie correlative object of tendency
(that is, of desiring, wanting, and so forth). From this analysis,
the conclusion emerges: a goal is that principle which influences
the coming-to-be of an effect inasmuch as by being the object
of tendency it influences the agent.

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B. NATURAL ACTIVITY

There is not much difficulty in establishing the finalization of
activity which flows from knowedge. But are other activities
finalized? For there are many activities which do not flow from
knowledge: the activities of nonliving things and of plants, and
those actions in men and animals which do not flow from knowl­
edge (such as digestion, growth, regeneration of tissue, reflex
actions, and sleep2). All such activities are called “natural activi­
ties.” Clearly we cannot say that such actions are purposive in the
sense that they proceed from the agent’s own conscious knowl­
edge. But can we in any sense speak of finalization of these
natural activities?
To help us see that this is a good question we can reflect that
in some fields of natural activity we distinguish between a normal
or natural result and a defective result. This is particularly the
case in the generation of living things: plants, animals, and men
are sometimes born defective in one way or another. The natural
processes of generation tend to normal results; if we did not at
least vaguely apprehend this tendency, we would never talk of
monsters or of healthy, full-formed births. A somewhat similar
indication can be found in some extremely complicated processes
of nonliving things, for example, in the formation of crystals.
Sometimes there are “defective” crystals, which occur when the
natural processes do not altogether succeed in reaching their
goal.
This vague indication of goal-directedness needs to be care­
fully explored and analyzed. Suppose we begin with the activities
’Note that finality is properly a characteristic of action. Io die classic
example of tlie archer and the arrow, the arrow in flight has a direction or
end temporarily imposed upon it—by tlie archer. Strictly, the arrow has no
intrinsic finality for the target, or even for any local motion. Modern thinkers
point out that local motion has no end of itself—and that is true, for they
arc considering the thing which moves locally (that is, the thing which ts
moved). But finality is to be sought in die agent, not in the patient. This
caution must be kept in mind diroughout.

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of living things without knowledge (and with similar activities
performed by agents which possess knowledge, but not as guides
of these activities). For example, a tree’s roots push through the
ground to find water. A tree growing in wet ground will have a
relatively shallow root system, whereas the same variety' of tree
growing in a dry spot will send its roots much deeper. The sprout­
ing seed pushes through even hard ground to get to sunlight. The
tendrils of a vine wind around supports to hold the vine upright.
Certain plants turn their flowers or leaves with the apparent mo­
tion of the sun to get more sunlight. What do these various activi­
ties show us? First of all, we see that a distinct result ts reached:
some new being or some new effect is attained. Secondly, we see
in living things a tendency, an impulse, a dynamism toward these
results. Even before the results are reached, there is an orienta­
tion of the activity toward them. Vital activity is in fact goaldirected.
The analysis of the activity of nonliving things is more difficult
than that of living things, and so our investigation will have to
proceed more slowly. In the first place, nonvital activities do
reach results. This fact is so obvious as not to need further ex­
planation. Secondly, the results of nonvital activities arc con­
sistent results. Of course, there is not an absolute invariability of
action and result. But there is a definite constancy, within limits,
so much so that physicists and chemists can construct mathe­
matical formulas for these activities, and so much so that in the
past two generations entire industries have been built on the
exact, universal knowledge acquired by scientists. Now, what
does the constancy of nonvital activities show us? It shows us
that nonliving things are, in a real sense, sources of activity. They
are not independent sources, it is true; other surrounding things
are necessary and frequently energy must be supplied. Nonliving
tilings, therefore, are real, secondary causes. Furthermore, these
nonliving things are intrinsically determined to their activities. If
this were not so, they would be determined entirely by circum­
stances, and constancy would vanish. Therefore, nonliving things

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149

have some intrinsic principle of determination to their proper
activities. Proximately, this principle is the power by which they
act; ultimately, the determination is from the substantial form,
by which each one of these things has its own given nature.
The result of this investigation can be summarized briefly:
nonliving things, as agents, are intrinsically determined to some
definite activities that have constant results. Now, we must ask a
further question: “Are nonliving things determined to act, as well
as to the kind of action?” “Or are they, on the contrary, pure
instruments which cause only as long as they are being made-tocause by another cause?” It must be admitted at once that there
is much passivity in nonliving things. It was suggested above that
local motion is a passion of the thing which moves rather than
an action. It should also be admitted that in some cases we do
not know very much about the activity of nonliving things. But
there seem to be some clear cases of real activity. When energy is
released through chemical action—for example, when phos­
phorus combines with oxygen—the material things themselves
seem to be active, not merely to be moved like instruments. At
some time in the past, energy was put in; but tin’s merely means
that such agents arc caused causes, or, in other words, secondary
causes. Again, there are activities like those of radium, which are
quite clearly cases of activity that is not merely instrumental.
By carrying this induction further, enough examples could be
found to enable us to conclude that nonliving things are truly
agents and of themselves tend to act, even if their agency or
efficiency is a very limited one.3
’Another way of discovering the goal-direetedncss of nonvital activity is
by examining the activity itself. Many complex natural activities take time
and occur in a series of distinguishable steps, which have an intrinsic rela­
tion to the results which they bring about. Modern chemistry finds it quite
practical to determine, from a consideration of the product that is wanted
(for example, a plastic of a certain hardness or resilience), the required
materials and the various stages and order of production. The order of
natural process is more strikingly evident when the activity of one agent is
interfered with by that of another, although it can perhaps be found even
in simpler activities.

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If there were no agents, there would be no need for goals of
action. For example, from the “point of view” of the lumber, the
coming-to-be of a table is in no sense a goal. This is because the
lumber is wholly passive in regard to the becoming of the table.
But an agent is precisely in some sense or other active, and that
means having a tendency and an impetus toward something.
Since there cannot be an impetus which is not an impetus toward
something, every action has a goal. Similarly, material things as
such are purely passive in regard to their own local motion. As
such, they are indifferent or “free” to move in any direction, and
so there is no finality in local motion if we consider only that
which moves. But from the point of view of that which moves it,
that is, the agent ( whether the agent moves by contact or gravi­
tation), local motion does have a direction and, consequently, is
finalized.
We can now summarize the results of our investigation of the
activity of nonliving things. Nonliving things, to the extent that
they are agents, are intrinsically determined to some definite
activities which have constant results and also intrinsically tend
to perform these activities.
C. THE CAUSAL ANALYSIS OF ACTIVITY

In studying activity, we must try to see it as a whole and try7 to
account for all its aspects. It is possible, and legitimate for certain
purposes, to consider activity abstractly. But, in the philosophy
of being, an abstract consideration is seen to be only a partial
one. Just as being is considered concretely and as a whole, so,
too, activity must be considered concretely and as a whole.
In Chapter V, we studied the intrinsic principles by which
being is constituted and by which change is possible. The in­
trinsic principles of being are concerned with the being itself. As
causal factors, they bring about the being in which they are. They
determine, specify, or structure a being in relation to itself. For
example, the form is that by which a being is what it is sub­
stantially, and the form brings with it certain properties ( namely,

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151

accidents) which perfect that being itself. So, too, the act of
existing is that by which a being itself exists. By understanding
these principles, we can understand how change is possible. But,
so far, we cannot say that change is actually taking place; nor can
we exactly decide what the effect will be.
Hence, in Chapter VII, we discovered that change demands
an extrinsic principle, the agent, by which the passive potencies
of beings are actualized. Given that there is an agent with its
tendencies ( active powers ), we can understand ( 1 ) that change
actually occurs,4 and (2) what the effect will concretely be;3 and
so we can have a full understanding of the coming-to-be of con­
tingent things. “Given that there is an agent,” we can understand
activity. But why should any being be an agent? Why should any
being be endowed with active and operative powers that are
tendencies toward new actuality?
Here, the analysis of human purpose activity shows us a fourth
causal factor, the end or goal, on account of which an agent acts.
We need to investigate this factor further, both in transient and
in immanent activity.
In transient activity, the direction of efficient causality is
toward the patient which, as such, is distinct from the agent.
Transient activity is an impulse toward a new being which does
not yet exist but is to come into being through that activity.6 The
fact that causality is directed toward the esse of another, namely,
of the effect, requires a causal factor over and above the prin­
ciples by which a being is constituted. And since the production
of a distinct effect is found in all transient activity, we can truly
say that every agent, as principle of transient activity, acts for a
goal or end.
Living things have immanent activities, and immanent activity
is, as such, the perfection of the agent which acts immanently.
‘See above, Chap. VI, sec. 41.
6 See above, Chap. VII, sec. 46.
* Hence, the nature of a being which has only transient activity is pro­
foundly different from one which has properly immanent action; see sec. 61.

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Plants bring themselves to their perfection by the immanent
activities of growth and nourishment and the immanent aspect
of generative activity. Animals and men perfect themselves by
exercising their powers of knowledge and appetition. These
activities are either desired for what they bring to the agent (and
so are finalized by a further end) or they are sought and valued
for themselves, in other words, are themselves goals (for ex­
ample, games, which are “for” nothing else, the contemplation of
truth, the exercise of sympathy, love, and so forth).
Sometimes, it is true, we speak of “aimless activities”; what
we mean is tliat where we expect a conscious purpose there is
none. For example, semiautomatic actions, like scratching one’s
head or drumming one’s fingers, are said to be aimless because
they are activities which ordinarily flow from a conscious pur­
pose. But here the purpose is not conscious, or perhaps the goal
is not a humanly desirable one—but there is a goal nonetheless.
In the explanation of immanent activity, therefore, the intrinsic
principles explain what a thing is, and how it is possible for it to
acquire further perfections. The thing in its substantial perfec­
tion itself is the agent which brings about the accidental per­
fection of immanent activity; but that the agent should act at
all, is the precise function of the end (goal, final cause).7 Con­
sequently, for both immanent and transient activity, the end is
the reason (cause) why the agent acts. In a word, every agent,
no matter what its type of activity, acts for an end.8
How is an agent finalized?
*
An agent which has knowledge
(sensor}' or rational) is finalized by the object known, toward
’ For a clear analysis of the causality of the end and the mutual influence
of the four causes on each other, see Selected Passage, No. 23.
•This proposition is often called "the principle of finality.”
* Previously it has been pointed out (sec. 39, n. 2, and sec. 46, n. 3) that
the passivity of a potency is not necessarily always passivity to the recep­
tion of an influence from an efficient cause. The fallacy of univocity in the
explanation of the passivity of tendencies to their final causes has led to
very elaborate theories which the very simple and direct understanding of
the analogy of potency makes useless and superfluous. This remark con­
cerns chiefly the theory of powers in the philosophy of human nature and
the theory of premotion in natural theology.

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which it tends by its conscious appetite. An agent which does not
have knowledge is finalized by its nature ( ultimately by its sub­
stantial form, proximately by the active powers which are the
properties of that form; by these powers the agent is adapted to
its ends). How can a substantial form be a formal cause and, at
the same time, a principle of finality, of goal-directedness? (This
is an important question which cannot be answered at this
point.)10

56. Finality in being
In tlie ver>' intelligibility of the act-potency correlation we
have a manifestation of finality. For a being in potency is a being
ordered to an act or perfection. For example, essence is ordered
to the act of existing by its very nature and so is intrinsically
finalized. The same is true of tlie other instances of the actpotency correlation; matter is ordered to form, is “for” form;
substance is “for” accidents. And all the beings which we know
directly exist for their operations. In other words, not only is it
true that all the agents we know directly act for ends but also,
because there are ends,11 these agents necessarily act (with dif­
ferent kinds of necessity depending on their natures).
But as we have seen before, there are two basic types of
operation, immanent and transient activity. Immanent activity,
as we have also seen, is the perfection of the agent, and so an
agent with immanent activity has an internal goal: it acts for
its own good, in some sense at least, and so, to that same extent,
exists proximately for its own sake. This is least perfectly true of
merely vegetative living things, for their highest operation, gen­
eration, is ultimately ordered to the production of a distinct
living thing. It is more perfectly verified in animals, which have
sensitive knowledge; but sensitive knowledge is very limited, as
we shall see in the philosophy of human nature. It is most perwSee below, sec. 69.
u Recall that as was explained above in n. I, some ends already exist and
need only to be obtained; other ends must be produced.

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fcctly verified in intellectual beings, whose immediate end is
their own perfection, to be attained by the possession of the good
which is the completion of their nature.12
On the Contran-, beings which have only transient activities
cannot be said to be for themselves. Their being is for the sake of
their effects; in other words, their goals are wholly external.
They share in activity only to the extent that they bring other
things to perfection. That is why some philosophers have found
only an extrinsic or instrumental finality in nonliving things; for
example, that they serve the ends and purposes of men, animals,
and plants. But this is a confusion. Nonliving things have an in­
trinsic principle of finality, their nature, but their goals are always
external.
57. Chance

The term “chance” is often used loosely to indicate that we do
not know the efficient causes or agents of a particular event
(coming-to-be). But if someone is ignorant of the causes of an
event, or even if the event cannot be foreseen (foreknown),
there is no philosophical problem about reality involved. For ex­
ample, ignorance may keep a person from knowing what a gun is,
but when such an ignorant person pulls the trigger and the gun
fires, the firing of the bullet is not chance. Again, we may not be
able to tell which way the dice will fall, but the chance wc take
is our ignorance, not the absence of causes for the event.
Some philosophers have taken the position that some events
happen without efficient causes. Of course, they admit that
within our immediate experience causes are always to be found
and to be expected. But for various reasons (some of which shall
be considered in the next chapter13), these philosophers main­
tain that some events remote in time or space occur without
efficient causes, and they state this supposed situation by saying
” As we shall see in moral philosophy, the end of man is the possession of
the subsistent truth (for knowledge) and goodness (for appetite), which is
God.
u See below, sec. 62.

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155

that these events happen “by chance.” Note that this is no
explanation. If, with these philosophers we would say, “Chance
is tile coming-to-be of some event without an efficient cause,”
then the statement, “An event has happened by chance,” means,
“An event has happened by the coming-to-be of that event with­
out an efficient cause.” This is the same as saying that something
comes to be without a cause. And, as we have seen in the pre­
ceding chapter, every being which comes to be has a cause.
However, there is another meaning of the term “chance” which
does offer a philosophical problem. We call that chance which
happens without design or expectation. For example, a man in
spading his garden comes upon a hidden treasure: we say he
found it by chance. The miser who hid the treasure had the pur­
pose of concealing or safeguarding it, not the purpose of having it
found. The man who was spading his garden had no purpose of
finding a treasure. Or another case: a man on his way to the
store met a robber at an alley; the meeting of the two men was
chance. What happens in such a case? There is a meeting of two
lines of causality, each of which is purposive in itself, but the
meeting of the two lines is not included in the purpose of either
agent. In this sense of chance, all accidents are chance. In this
sense also, we can correctly speak of chance even in the world
below man. The stone on top of the mountain is pulled by
gravity, which is a goal-directed activity, toward the bottom. A
plant halfway up is engaged in the goal-directed activity of grow­
ing and nourishing itself. But the destruction of the plant by the
descending stone is not due either to the causes which pull the
stone down or to the activity of the plant; it is a chance result
due to the interference of two lines of activity. For another ex­
ample, we know that when molten iron cools without interfer­
ence, it takes a crystalline structure which is relatively brittle.
When it is violently pounded while cooling, it becomes tough and
malleable. From the point of view of either the iron itself or the
forge, the malleability of the iron is a chance result due to the
interference of two unconnected lines of activity. Hence, we can

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define chance as “the concurrence or interference of several
causal chains,14 such that the concurrence is outside the goal of
any of the causes taken singly.”
Chance, considered from the viewpoint of the agents immedi­
ately involved, is certainly something real. Because this consid­
eration is restricted to the immediate or proximate agents, we
will call chance taken in this way "relative chance.” But this is
not the only way in which we can consider chance, as is clear
from the example of the iron and the forge, for what is chance
from the viewpoint of either of those causes is intended by
the operator of the forge. If, then, we take into account all the
causes involved in an event, both proximate and remote (or
mediate) secondary15 causes, we would have a complete and
absolute consideration, so that, if a chance event occurred with
respect to all these causes, it would be an absolute chance.
Can there be an absolutely chance event or effect? To answer
this question we must first distinguish between a positive chance
and a merely destructive one. Most chance events are less per­
fect (less actual, and so on) than the effects which the causes
would have produced if they had not been interfered with. With
such an event there is really no problem of causality and
finality.16 But what about positive chance results? Let us sup­
pose an effect arising from an interference of distinct causal
lines, which is more perfect than any single one of its proximate
causes.17 When we were considering efficient causality, wc saw
“ Recall that natural finality or deliberate purpose will be finalizing each
one of these lines of causality in itself.
,s On the meaning of the term, "secondary cause,” sec above, sec. 47.
w Imperfection, or Jack of act, does not need an efficient cause, since as
such il tv not. Supposing that God exists (which wc have not yet con­
sidered philosophically): such a destructive result would indeed fall under
His foreknowledge and providence and could not happen unless He per­
mitted it; yet He would not be its cause.
” To the extent that more perfect living things were born of less perfect
ones their origin would be ascribed to chance. How a nature can arise in
this way will be considered in general below, sec. 69, and more specifically
in the philosophy of nature; see G. P. Klubertanz, Philosophy of Human
Nature (New York, Appleton-Ccntury-Crofts, 1953), pp. 405-407; 422-425;
"Chance and Equivocal Causality,” Proceedings of the Xlth International

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that an effect may possibly be more perfect, more actual, of a
higher degree of being than any one of its proximate causes, but
not more so than all of its causes taken together, else it would be
really uncaused. The situation with regard to final causes is not
altogether the same. A positive effect may well escape the finality
of any of the proximate and particular causes and so be a rela­
tively chance effect. Moreover, granted a real plurality' of con­
tingent beings, and granted especially the real internal freedom
of some finite agents, a positive chance effect may escape the
finality' of any and all secondary causes.18 Is this a sufficient and
complete analysis? If we were to say that an event or a being in
its coming-to-be has escaped the finality of every cause without
any qualification at all, would we not be forced to hold that the
determinate nature of the effect has been simply uncaused?
Would this not be a contradiction? For we would hold that this
determinate nature would be actual of itself and yet have begun
to be. This problem brings us to the topic of the next chapter.
58. Definitions
Goal, end, or final cause, is that to which an activity' is directed.
It is that for the sake of which something exists or is done. It
is the cause which influences the being of an effect by being
the object of an agent’s tendency'.
Purpose is a consciously held goal.
Finalization is the being-directed toward a goal.
Finality is the being-ordered or directed toward something
which is a good or perfection in some sense.
Chance is the concurrence or interference of several causal
Congress of Philosophy, VI (1953), 203-208. This article also shows how
the statistical character of some scientific laws is to be related to both
efficiency and finality.
’* To suppose the opposite is to admit mechanical predetermination. Such
a system of thought would hold that a sufficiently powerful intellect (for
example, Laplace’s demon), given an adequate knowledge of any moment
of world history, could discover all the events which led up to it and
predict all subsequent events.

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[58-60]

chains, such that the concurrence is outside the goal of any of
the causes taken singly.
Relative chance is the concurrence of several causal chains
which is outside the finality' of the proximate causes involved.
Absolute chance is the concurrence of several causal chains
which is outside the finality of all secondary causes.
59. Proof

Action is either immanent or transient.
But: immanent action is itself a perfection of the agent and so
an end or goal; transient action flows either from a conscious
purpose or from a nature so structured as to act toward constant
and determined results.
Therefore: every' agent acts for an end.
60. Readings

St. Thomas Aquinas, Contra Gentiles, Bk. Ill, chaps. 2 and 3 (every
agent acts for an end which is a good), chap. 16 (every limited being
has a goal); Summa Theologiae, Pt. I, q. 5, art. 4 (how the causes are
related); q. 44, art. 4 (God is the end of all beings); Pt. I-II, q. 1,
arts. 1 and 2 (finality in human activity'), q. 26, art. 1 (love and the
good).
Etienne Gilson, The Spirit of Mediaeval Philosophy, trans. A. H. C.
Downes (New York, Scribner, 1936), pp. 102-107.
A. D. Sertillangcs, Foundations of Thomistic Philosophy, trans. God­
frey Anstruthcr (St. Louis, Herder, 1931), pp. 148-158.
Selected Passages from St. Thomas Aquinas

23. That the End Is a Cause
The fourth kind of cause is the goal (end). This is that for the sake
of which something happens, as health is the cause of walking. Be­
cause it is less evident that the end is a cause, since it is the last to
come to be, therefore also was it omitted from consideration by earlier
philosophers, as is noted in the first book. Hence, [Aristotle] proves in
a special manner that the end is a cause. For the question, “Why?” or
"On what account?” is a question about a cause. For when someone
asks us, "Why, or for what reason, is someone walking?” we give a
suitable answer when we say, “For his health.” And in answering this
way, we think we are giving the cause. Hence it is clear that the end

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is a cause. Not only the ultimate end for which the agent acts is a
cause with regard to those things which precede it, but all the inter­
mediate steps between the first agent and the ultimate end are called
ends with regard to what precedes them. In the same way, the inter­
mediaries are called the agent cause and source of motion with regard
to what follows them. . . .
Since the term cause has many meanings, it happens that there are
many causes of one thing, not accidentally, but properly. . . . For
the cause of the statute, in itself and not accidentally, is the sculptor
and the brass, but not in the same way. . . .
He says that it also happens that two things are causes with regard
to each other—but this is impossible in the same kind of causality.
This indeed becomes clear if we consider that causes are of many
kinds. For example, the pain from a wound is a cause of health, as
efficient cause or the principle of change; but health is a cause of that
pain, as end. For according to one and the same kind of causality it is
impossible that one thing be both cause and caused. . . .
We ought to understand that, of the four kinds of causes previously
mentioned, two of them correspond to each other, and the other two
also. For the efficient cause and the end correspond to each other, in
that the efficient cause is the principle of change, and the end is its
term. Similarly, matter and form correspond to each other, for the
form gives esse, but the matter receives it. Therefore, the efficient
cause is the cause of the end, and the end is the cause of the efficient
cause. The efficient cause is the cause of the end, inasmuch as it makes
it to be, because by bringing about change, the efficient cause makes
the end exist. But the end is a cause of the efficient cause, not indeed
of its being, but with regard to its causality. For the efficient cause is
a cause inasmuch as it acts, and it docs not act except for the sake of
an end. Therefore, the efficient cause has its causality from the end.
Form and matter arc causes of being with regard to each other.
Form is the cause of matter, inasmuch as it makes the latter to be in
act; but matter is the cause of form, inasmuch as it sustains it. But I
say that both of these are causes of being for each other, either simply
or in some regard. For the substantial form gives being to matter sim­
ply. But the accidental form does so in a qualified manner, inasmuch
as it too is a form. Furthermore, the matter does not always sustain
the form in being simply, but inasmuch as the form is the form of this
matter, having its being in it, as the human body is related to the
human soul.
Commentary on Aristotle's
Metaphysics, Bk. V, lect.
2 (ed. Cathala, Nos. 771,
773, 774-775).

CHAPTER IX

God, the Cause of Limited Being
61. The problem1
In studying the being and action of things around us, we have
found certain structures and characteristics that are analogously
common to all of them. We have seen that every being of our
experience is something that has an act of existing, that it is con­
sequently a limited being, and that it is therefore existentially
contingent.2 In studying the action and causality of these beings
which are limited, we have seen that every one of them is a
secondary cause. In other words, the very action and causality of
these beings is dependent in one way or another on other distinct
beings, and that in the two directions of efficiency and finality.3
The question now arises: "Is all reality of this same nature and
structure?” "Or, as most men hold, is there a being or beings of
quite a different sort, commonly called by them God?”
This question is complicated by a difficult}' raised by some
recent philosophers. They want to know how anyone could
claim to know a reality which was allegedly outside experience.
Of course, we can think of many things which we have never
‘It was explained above (sec. 2) that metaphysics and natural theology
are not two distinct philosophical disciplines. A complete metaphysics, in
fact, includes natural theology. For purposes of learning, some division has
to be introduced, and so in this introductory study of being, we intend to
take up only enough about the first principle of experienced being to make
the latter intelligible to ourselves. In a sense, of course, the whole of natural
theology is contained in the proofs for God’s existence. But it still needs to
be unfolded. So, after a student has completed the introductory course in
metaphysics, natural theology’ will still provide a challenge to his thinking
and learning.
’ Above, secs. 10, 20, 34, 41 (3), and 50.
* Above, secs. 46, 47, 50, 55, and 57.
160

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experienced, but it is maintained that all such “things” are either
possible material things (like the spaceship not yet built) or
simply unreal objects (like the chimera or the objects of mathe­
matics). The question then is: “How do we come to know real
tilings of which we have no immediate experience?”
Furthermore, some people assert that there is evidence to show
that there is no God. They allege, and rightly, that almost all
who accept the existence of God agree that He is good. How,
they ask, can a good God be the source of imperfection, suffering,
evil, and sin? Are not evil and disorder evidences that the world
did not proceed from an all-good source?
62. Solutions
In general, all who accept the existence of God in any way,
are called “theists.” Conversely, those who do not, are called
“atheists.”4 More accurately, an atheist is one who denies that
there is a distinct intelligent cause of the material universe.
Usually, an atheist also has some positive doctrine about the
ultimate nature of reality. Most atheists are materialists of one
sort or another.
Materialism is the doctrine that only mass and motion are
ultimately real, or that matter is the only substance. Mechanism,
which is now almost entirely obsolete, held that all activity in
the universe could be reduced to mass and motion.5 Modem
* On atheism, see the very illuminating study by Jacques Maritata, “The
Meaning of Contemporary Atheism,” The Range of Reason (New York,
Scribner’s, 1952), pp. 103-120. For a more extended and literary treatment,
see Henri de Lubac, S.J., The Drama of Atheistic Humanism (New York,
Sheed and Ward, 1949).
6 The term, “reduce,” has a special meaning in the area of knowledge. We
say that A can be reduced to B when B is shown to give us the essential
intelligibility of A. Thus, by means of the parallelogram of forces, two forces
acting at an angle to each other can be shown to be equivalent to a single
force, and the direction and speed of the motion deduced. Similarly, com­
plex motions can be reduced to a series of simple motions. In this way, too,
materialists would like to be able to show that vital activity is only an
enormously complicated series of physicochemical activity, and conscious
activity is only a very, very complicated vital activity. Sometimes, such
attempted reduction is called “the fallacy of nothing but.”

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materialism admits that conscious activities cannot be reduced to
local motion but maintains that nevertheless all being is material.
If materialism includes an explanation of human history as de­
termined by evolving material conditions, it is usually called
dialectical materialism (or theoretical Marxism). Dogmatic ma­
terialism maintains that matter is an adequate and satisfying
explanation; at the present time this philosophy is more com­
monly called “scientific naturalism” or “scientific humanism.”6
Critical or positivistic materialism holds that the search for any
ultimate explanation is impossible, meaningless, or futile; the
modem form of this doctrine used to be called “logical posi­
tivism” or “logical empiricism”; in its contemporary stage of
development it is often called “philosophical analysis” or “ana­
lytic philosophy”; in an extreme form it is called “general
semantics.”
Pantheism is the doctrine that the world is God or God is
the world. It has taken and takes many forms: nature-pantheism,
idealistic pantheism (which holds that sensible things either have
no reality at all or only the partial reality' of illusion), atheistic
idealism (which denies the existence both of matter and of a
God distinct from the spirit, mind, or idea), and so on.
Theists we have defined above as all who in any way accept the
existence of God. For our purposes, we need to make a distinc­
tion among theists, for some of them hold that we can certainly
know the existence of God, and others do not. Agnosticism is the
doctrine that we cannot know or at least cannot know with cer­
titude that there is a being outside the material universe. Agnos­
tics who are theists usually accept God for some noncognitive
reason. Sentimentalists maintain that although we cannot know
there is a God we can feel his reality'. Fideists claim that we
cannot know or at least cannot prove the existence of God, but
we accept it on faith or tradition. Pragmatists who are theists
* "Humanism” in this sense is obviously something quite different from the
humanism which is tile aim of the liberal arts program; the latter is called
humanism because it aims to educate the "whole man”; the former, because
it denies that there is any reality superior to man.

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hold that God’s existence is a meaningful postulate and “true" in
the sense that it is important in a man’s life. Neo-Kantians hold
that the postulate of God’s existence is not only important but
necessary for freedom and moral action; they maintain, how­
ever, that it cannot be proved in the sense of a rational demon­
stration.
63. The question of knowledge
In asking the question, Does God exist? we must clearly
understand its import. We are not asking whether we can know
God in Himself without relation to the world.7 Some thinkers
have tried to assert that we can have an immediate experience of
God by means of a natural mysticism.8 There is no question but
that there can be a mystical experience of God in some way; but
we can safely assume that this is not the common experience of
men. Moreover, it can be proved that as long as we are in our
present condition of knowing, it is impossible to have an immedi­
ate knowledge of God as He is in Himself.®
Our knowledge of the existence of God is therefore some kind
of mediate knowledge of God inasmuch as He has some relation
to the universe. At the level of unrcflective, spontaneous knowl­
edge10 most people know with certitude that God exists. We are
not going to question this knowledge; in other words, we are not
going to doubt God’s existence. Our question is, Can there be a
demonstrative (scientific) knowledge of the existence of God as
the cause of the beings of our experience?
To ask a question about the cause of the material universe is
obviously not to ask about univocal causes. Univocal causes are
T On the kind of knowledge we can have of God and of other spiritual
things, sec Selected Passages, No. 24.
8 “Mysticism” means (a) a kind of internal experience of some remarkable
working of God in the soul; (b) die Uieoretical explanation of such experi­
ence.
"See, for example, St. Thomas Aquinas, Summa Theologiae, I’t. 1, q. 12,
arts. 2, 3, and 4; also sec below, secs. 67 and 68, for a brief statement of
the kind of knowledge we do have of God.
* See above, see. 1.

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of the same nature as their effects and so belong to the same
material universe as those effects. Moreover, all univocal causes
are secondary causes; that is, they presuppose other causes and
a pre-existing patient upon which to act. Hence, univocal causes
are never total causes of the whole being of the effect. Univocal
causes can be arranged in an historical series; that is, one pre­
cedes the other in time. An example of such a series is the
“father and son” series of human beings. Now, suppose we were
to ask whether a given man had a father and whether this father,
in turn, had a father, and so on down the series; it would be
absurd to wish to follow such a series and at the same time to
hope to arrive at a First Cause. An historical series of univocal
causes is a series it is true; but its order is accidental (con­
tingent),11 not necessary. Some people think that an accidental
or historical series cannot be infinite; hence they conclude that
the entire world had a beginning in time and that therefore there
must be a cause who is at the beginning of the entire universe.12
This argument is not nearly so simple as it looks at first sight,
and we will make no use of it.13
In addition to univocal causes, there are nonunivocal (analo11 This order is accidental, because “to cause this individual effect,” and
“to be caused by this particular agent” belong neither to the constitutive
essence (substantial or accidental) nor to the properties of the things con­
cerned.
On the other hand, the order of instrument to principal cause is essential
or necessary, for the instrument as instrument actually exists as such only
when it is moved by the principal cause.
“ Distinguish between the statement, “An historical series cannot be infi­
nite,” and the statement, “Scientific evidence indicates that our universe
( in its present form ) in fact began its evolution at a specified point in time."
Modem cosmogonies almost all demand a temporal origin—billions of years
ago—for the present stars and nebulae. But they do not unequivocally prove
that this point is an absolute beginning.
** St. Thomas wrote a special treatise, On the Eternity of the World, in
which he concludes that it cannot be proved that an historical (or acciden­
tal) series cannot be infinite. Of course we know, by an infallible revelation,
that the universe in fact began in time, but this is not our question—
knowledge by faith is not the point of our present investigation. An argu­
ment which is not rationally certain should not be used, especially since we
do have really sound arguments at our disposal.

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gous and equivocal ) causes. We have already seen,14 though only
in a brief way, that there are such causes in the real order. A
nonunivocal cause is one which is not of the same nature as its
effect but has an equivalent perfection (equivocal cause) or a
similar and greater perfection (analogous cause). The relation­
ship between an effect and its nonunivocal cause involves both a
dependence of the effect on its cause and an inequality of perfec­
tion in effect and cause. This inequality in perfection or act we
have called “causal analogy” or “the analogy of eminence in
causality.”15
If there is a series of analogous causes, as for example, in the
relation between a principal cause and its instrument, this is an
ordered series. But note that this is not an historical order of
sequence; there is no time involved in such a relationship. The
order is an order of dependence; the instrument depends on the
principal cause precisely for its causality, and this order cannot
be reversed (the pencil cannot become the principal cause, and
I cannot become the instrument of the pencil). This order of
dependence in causality is therefore intrinsically necessary to the
causality and so is a per se order.
G4. The question of proof
To answer the question, Arc there men? we need but point
and then show that what we point to verifies or realizes what we
mean by man. Strictly speaking, this not a proof; at most it is a
pointing out of the evidence which is immediately available. To
answer the question, “Is there a city called Montreal?” we might
have to have recourse to the testimony of some one who had been
in contact with immediately available evidence. Strictly speak­
ing, this also is not a demonstration; testimony never makes us
see the truth of what we believe on testimony. And it should be
noted that testimony can never be used precisely to testify’ to the
14 On the distinction between univocal, analogous, and equivocal causes,
see above, sec. 47.
“ See above, sec. 51.

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existence of the testifier (it may testify to his name [“Are you
John Smith?”] or his nature, substantial or accidental [“Are you
English by descent?”] ).
Anyone who asks, “Is there a God?” is asking because he has
not had any immediate experience of that being. We do not mean
to imply that such experience is possible or not possible; we are
concerned only with the fact. As students of metaphysics, we are
dealing with being and the causes (principles) of being accord­
ing to the proper intelligibility of being and not with what
authoritative witnesses or documents may have had to say about
it. As far as investigating testimony is concerned, that is not the
job of philosophy (but of histon' or at least of an historical sci­
ence). Hence, neither the way of immediate evidence nor that of
testimony is available to us. And so we must use some kind of
proof.
Proofs can be classified in many ways; what concerns us now is
the point of departure which is used in a proof. From this point
of view proofs are divided into those which proceed from cause
to effect and those which proceed from effect to cause. The
former we will call “causal proof’ (sometimes called a propter
quid demonstration, for it tells us that a thing is and also why it
is); the latter is called a “fact proof’ (or quia proof, for it tells
us only that something is).
Strictly speaking, it is impossible to use a causal proof to prove
the existence of a First Cause, for precisely what we mean by a
“First Cause” is one tliat itself has no cause. But it may be
possible to use something which for us ( considering our way of
knowing) is in the place of a cause; such a proof can be called
“proof from a prior reason” (fl simultaneo, because it proceeds
from something which is really identical with the existence of
the First Cause but with regard to our way of knowing is prior).
The “proof from a prior reason” can be formulated in several
ways. St. Anselm expressed it thus: (1) God exists in the mind—
we can think of Him. (2) God is that than which a greater can­
not be thought of. (3) To exist both in reality and in the mind is

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greater than to exist in the mind alone. (4) God exists in reality
Leibniz puts his proof this way: (1) God is a necessary being.
(2) If a necessary being is possible, it exists. (3) The necessary
being is possible. (4) Therefore He exists. Both of these proofs
depend for their validity on the implied premise that God is real.
St. Anselm, of course, was working within faith—he already
believed that God exists; but independently of faith, all that St.
Anselm’s proof proves is that unless we think of an existing God
we are not thinking of God at all.16 Leibniz’s proof hinges on this:
that the necessary being is not merely possible-to-be-thought-of
but is really possible. But how anyone is to arrive at such a
knowledge prior to his knowledge that there is a God is in­
explicable. Since these two formulations of the “proof from a
prior reason” are considered by all who try to use such a proof
to be the very best ways to put this proof, we can conclude that
such a proof is either impossible or presupposes what it claims to
prove. Therefore, the only way we can prove the existence of God
is by a fact proof.17
What precisely does a fact proof do? In general, it proves that
something is or is such and such by means of a point of departure
which in the course of proof becomes known to be dependent
upon what is to be proved. The structure of that proof, still in
general, is something like tins: “Given X as a fact, we see by in­
spection and analysis of X tliat it depends upon Y; therefore Y.”
The fact proof has two major forms: one in which we proceed
from a property to an essence, which is proceeding from effect
to cause (and this proof can be cast into an Aristotelian
syllogism); the other in which we proceed from one thing to
another which is its efficient cause, and this reasoning process is
too complex to be put into a syllogism. It is only the second type
of fact proof which is in question here, and the structure of that
proof precisely must be (1) something given in experience (2)
wWe are not investigating what St. Anselm himself meant by bis argu­
ment or what his contemporaries understood but rather what our contempo­
raries would make of it.
17 On the sources of our knowledge of Cod, see Selected Passages, No. 27.

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from which wc come to see gradually that this given necessarily
implies an existent as its cause.
If we were to rest content with the conclusion that there is
a cause of material being and not investigate whether we are
asking for a univocal or an analogous cause, our fact proof would
be simple and syllogistic. Our argument would follow a pattern
something like the following proof:
“A man has died of wounds which were not self-inflicted.
But: such wounds are only caused by a killer.
Therefore: There is a killer.”

A detective would not be content with such a conclusion. He
must indeed know whether a killer is to be looked for, and to that
end he must determine that the death was not accidental or selfinflicted. But his major problem is, “Who is the killer?” The
proof for this is no longer syllogistic.
Similarly, when we ask, “Does God exist?” we cannot be con­
tent with the conclusion that a cause of material being exists; we
must identify this cause as God. Therefore, in addition to the two
steps of argumentation mentioned above, a third is necessary,
in which we conclude that the existent cause of the material
universe is God.

65. Evidence and argumentation (I)
(1) It is given in immediate experience that change is going
on (in the general sense that there are transitions from potency
to act, as for example, some local motion is beginning, growth
is going on, someone is beginning to know).
(2) [a] Something passes from potency to act only through
the agency of a being in act.18
[b] It is impossible that there be an infinite series of
agents such that each while being tlie cause of change in another
is itself being changed so as to cause.
” See above, Chap. VII, secs. 46 and 50.

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N.B. This is not a question of an historical series of univocal agents,
for such a series does not explain why an agent is causing here and
now. We are talking about a series of causes that are of themselves
and intrinsically subordinated and, consequently, arc not univocal but
analogous or equivocal causes. The characteristic of a per se series is
that each dependent member of the series is precisely what it is through
its dependence on another. In the present case, every subordinate
member of the series is actually causing existential act by receiving an
existential influence. Now to say that there is a series (finite or infinite)
such that each member of that series depends on something other, and
such that the whole series (or tlie first member, if the series is finite)
does not depend on something other which is what-it-is without being
caused—this statement is self-contradictory and therefore meaning­
less.

[c] Therefore there is a First Cause of the actual existen­
tial causality of per se ordered causes. This cause is, and is a
cause, by the analogy of eminence in causality. Because it is a
First Cause, it is in no way caused by another and so cannot have
any real potency; it is pure act.
(3) Therefore, a First Cause exists, which as First is unique
and supreme, and this is the Cause which we call God.
66. Evidence and argumentation (II)
(1) It is given in immediate experience that contingent beings
exist (for anything which changes is existentially contingent,
such that what-it-is is really distinct from its act of existing).
(2) [«] But that which is existentially contingent depends on
a cause for its existence.19
[b] It is impossible that there be an infinite series of
existentially contingent beings such that each of them depends on
another for its act of existing.

N.B. An existentially contingent being is because of another which
here and now is the cause of its being (as every- effect, formally speak­
ing, depends on its cause, here and now, for its being as effect). To
say A exists because of 13, and so on, implying thereby that none of
the existential causes exists of itself, is to say that things both exist
and do not exist.
” See above, sec. 50.

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[c] 'lliercfore, there exists an existentially necessary
being on which all contingent beings depend precisely for their
existing, and in this being essence is necessarily identical with its
act of existing. Hence, this being is pure act in the order of
existence and so is absolutely unlimited, fully actual of its nature,
completely perfect.20
(3) Therefore, there exists a First Cause in the order of
existence, which is pure act in that order, whose essence is iden­
tical with its act of existing, which is therefore properly named
“Who is” (without any limitation), and this is God.

67. The analogy of participation

The basis for our argument has been the existential dependence
of secondary causes and of contingent beings upon an efficient
cause. Previously21 we have seen that nonunivocal causes are
similar to their effects according to the analogy of eminence in
causality. But this relationship, taken by itself and in the abstract,
does not enable us to decide whether the nonunivocal cause is
analogous or equivocal—in other words, whether the cause is
intrinsically and properly in itself analogous to the effect or
is only truly denominated such (as a healthy climate is not prop­
erly “healthy” but is truly denominated healthy because of its
influence upon the health of living things).
Let us look at the analogy between God and sensible things,
no longer abstractly as an instance of eminence in causality but
concretely, in regard to what is truly said of God in our conclu­
sion. We say that God is. And we mean that He is, in the sense
that He is actually exerting a causal influence upon the causality
and existence of real things in the proper sense of the term real.
We have seen above22 that “is” in the metaphysician’s sense
means “exercising or having an act of existing.” We have seen23
* See above, sec. 40.
” See above, sec. 51.
® Secs. 10 and 12.
"Above, sec. 46.

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that the causality of an efficient cause is an expression of the
intrinsic dynamism of the act of existing;24 and that conversely
that which does not exist cannot be an agent. Therefore, the “is”
which we predicate of God means a real and intrinsic act of
existing, and so is predicated according to the intrinsic analogy of
eminence in causality.25
Furthermore, God is the First Cause. Therefore, no other being
can be related to Him as cause to effect. Since potency is un­
intelligible and impossible unless there is an act of which this
potency precisely is the potency,20 there can be no intrinsic or
receptive potency in God. He is therefore pure act—not the act
which is the act of a potency and is received into the potency as
a principle of being but an act which is the subsistent thing itself.
And this act is the act of existing. Hence, God is a subsistent act
of existing. We have seen above27 that an act is limited and
multiplied only by a potency in which it is received. If an act
is subsistent and not received, it is necessarily perfect, unlimited,
and unique, and thereby distinguished from all received acts.28
Hence, God, as a pure act of existing, is the perfection of all
existence, infinite and unique and distinct from all the beings
which have an act of existing. His nature, inasmuch as we can
use the term “nature” of God, is to be—simply, without any
limitation.
If God, by His nature or essence, is His act of existing, it
94 This statement need not imply that an agent acts necessarily. Only when
an existing agent is a nonfree agent does it act necessarily; a free agent acts
freely. But whether an agent acts freely or necessarily, its activity and its
causality both are a kind of “superabundance” of act, a kind of overflowing
of the actuality of esse. Less metaphorically, esse is the source within a
being of all its other acts.
“Because the kind of argument we use to arrive at a knowledge of the
existence directly docs not enable us to decide whether the eminent cause
is analogous or equivocal (see above, sec. 51), no direct knowledge of sub­
sistent esse is implied; see St. Thomas, Summa Theologiae, Pt. I, q. 3, art.
4, ad 2.
” See above, sec. 40; see also below, sec. 73.
“Sec. 40 (3).
* On this distinction between God and creatures, see Selected Passages,
No. 26, at the end of this chapter.

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follows that wc can say that His essence is to exist; God is by
His verj' essence. All beings other than God are because they
share or participate in a “common" act of existing; they are by
participation (namely, by participating in the act of existing).
Here then wc have a new analogy, which we may well call “the
analogy of participation.” 29 When we say, “God is,” we designate
an act of existing which is a nature; when wc say, “A limited
(contingent, caused) thing is,” we designate an act of existing
possessed by, received in, and limited to, a potential subject­
essence.
Being and the properties of being (the transcendentals) are
properly predicated of God according to the analog}' of partici­
pation.30 What about some perfections which in man are strictly
accidental, such as the perfection of wisdom? Such perfections or
attributes, if they are really and unqualifiedly perfections, can be
predicated of God positively and properly, according to an anal*The relation in being between God and any finite tiling is the only in­
stance of the analog}' of participation in being. In the next chapter, we will
see that the analogy of participation in the transcendentals (good, true, and
so on) also is found between God and any finite being. See also, Selected
Passages, No. 25.
In addition to these basic, essential instances of the analogy of partici­
pation, where efficient causality is intrinsically involved in the analog}', it
may be helpful to mention that there are other instances of the analogy of
participation in which efficient causality is not directly involved. We can
correctly speak of the analog}’ of participation whenever one being is by
nature what another is by nonessential (that is, which is not a part of the
essence) received act. Hlius, human beings are not, in the strict sense of the
word, intelligent by nature but rather rational, which implies a connection
with sensory life. Nevertheless, men do occasionally perform acts of simple
intelligence through their power of intellect, which, as operative power, is
an accidental act in relation to substance. Angels, on the other hand, are
simply intellectual by nature (though not by being), for the only operations
they have are on the intellectual level. Hence, man, in his acts of simple
intelligence, can be said to participate in angelic intelligence. We can find
another instance of participation within man himself. Thus, man’s higher
sensory powers, through the reception of an influence from his intellect,
sometimes act in a way which is imperfectly similar to the way in which
intellect acts by its nature. In this meaning of the term, a man’s emotional
life can be said to be reasonable, not by nature but by participation.
•How we can name God is discussed more fully in Selected Passages, No.
30.

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ogy of proper proportionality'. Thus, once the existence of God
is known, and also His complete perfection, we can truly predi­
cate the perfection of wisdom of God, for, as a wise man orders
all his actions according to their real value, so God’s effects are
ordered according to their intrinsic values.31 But let it be noted
that no analogy of proper proportionality between God and any
finite things can be used until we first know the existence of God.
Now that we have seen, at least in outline, the whole scope of
analogy, it will be useful to organize and interrelate all the kinds
of analogy'. The analogy' of participation is the last to be dis­
covered, but it is the primary and basic one. God is by His
essence, and when He, as an analogous cause, makes things to be,
He communicates to them the perfection of being in a partial and
limited way, so that these things are by participation. Through
the analogy' of eminence in causality' there arise many' partici­
pants in being. Each thing which is by participation is somethinghaving-esse, and therefore each is related to every' other one by
an analogy of proper proportionality. Because any thing which
has esse is intrinsically composite, and because such a nature is
a substance which acquires perfections which are accidents,
within a being there is an analogy of proportion, so that all
the internal principles of a being can themselves be called beings.
Because these internal principles stand in a series of similar re­
lations to each other, we discover the act-potency correlation
and find that act and potency' are analogously verified in the case
of the constitutive principles of being according to an analogy' of
proper proportionality.32 Because things which exist by' participa­
tion are capable of being modified—in all cases accidentally, in
some also substantially—they' can stand in multiple causal rela” See, in addition. Selected Passages, No. 27.
“ In addition, “act” is said of esse and of form analogously, according to
the analog)’ of proportion; this is an extrinsic analogy, as explained above,
sec. 41, n. 12.
Furthermore, there is an analogy of proportion, according to which the
intrinsic principles of composite substance are called substance; form is called
substance more properly, matter, less properly, inasmuch as it is related to
and perfected by form. See above, sec. 32.

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tions with each other. Among these are causal situations wherein
the effect receives the communicated perfection in an essentially
imperfect way. Hence, even among secondary causes there is to
be found the analogy of eminence in causality.38
The dependence of all beings on God is a total dependence.
Hence, our universe of experience, and all beings contingent,
exist by creation, that is, their whole being is from God. By
creation we understand the complete and total dependence of
one being with regard to its entire being upon another as upon
its total cause. An equivalent definition is the more common
statement that creation is the production of a thing, no subject
and no other cause being presupposed.
When did creation happen? The arguments we have used, as
well as the other arguments of St. Thomas, conclude that the
entire universe exists by creation. These arguments simply do
not enable us to decide whether created things have been in
existence for a limited time or from all eternity.

68. Answers to objections

Against the second argument (which is the “third way” of St.
Thomas), some writers object: “A conclusion cannot be stronger
than the premises; but we begin with contingent things; therefore
we can only reach a contingent being in our conclusion.” The
answer to this is: the beings with which we begin are contingent;
but that they are contingent is true with absolute, even though
only consequent necessity. Furthermore, the link from effect to
cause (no matter what the nature of the effect, provided only that
it is), is absolutely necessary. Hence, the argument to a necessary
being is completely valid.
The objections of agnostics and positivistic empiricists are
based on a consideration of purely conceptual (therefore uni­
vocal) knowledge and on essences. They maintain, either explic­
itly or implicitly, that we must know what a thing is before we
can know that it is, or, at the very least, that we must be able to
“ For an outline summary of analogy, see Chap. XIV, sec. 108.

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state its essence. But we maintain that there is knowledge in addi­
tion to the conceptual knowledge of essences, namely, judg­
mental knowledge, and that there is a principle of reality beyond
essence, namely, the acts of existing and activity. It is true that
the knowledge we ultimately arrive at is analogical and strictly
limited. We do not know with any proper knowledge what God
is. We know, first of all, that the statement, “God is," is true. But
further reflection on the implications of the fact proof by which
we know that God is gives us the conclusion that in Cod there is
no receptive potency, so that He is a pure act (subsistent act) of
existing. We know, further, that this perfection of existing, which
we cannot comprehend, englobes in a unity the perfections of
creatures in an eminent way. Hence, we can summarize our
knowledge about God thus: it is positive inasmuch as we assert
truly that God is the cause of the various perfections which we
experience and that therefore He is, simply and unqualifiedly;
it is negative inasmuch as all univocal perfections, and even more
all imperfections, must be denied of Him; it is knowledge by
eminence, inasmuch as the act of existing—which even in crea­
tures is the act of all other acts—when it is a subsistent act, is,
in a simple way which we cannot grasp in a concept or any
number of concepts, all the perfections of creatures and infinitely
more.
The objections against the existence of God which are based on
the reality of evil cannot be answered in such a way that evil will
cease to trouble us. But the following things can be said, (a) No
creature can be absolutely perfect; it is necessarily a limited
being. Moreover, as limited in being, it is contingent, and so in
one way or another is able to fail, (b) No one creature can be as
good an effect as a universe composed of many differing kinds of
beings. But this very plurality, which is good, entails necessarily
the possibility of conflict, contrariety, and the like, between those
creatures, (c) Rational and free beings are the greatest, most
perfect kinds of creatures (as we will see in the philosophy of
man). But if God really means to create a large number of free

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beings, who are good inasmuch as they freely fulfill the law of
their nature and destiny, then, being really free and limited (con­
tingent), it is absolutely necessary that they be able (and hence
be allowed by God) to fall into moral evil, (d) Finally, if God
who is good is to be the author of a created universe in which
there is to be evil, this can happen only if God can and does
draw forth good from that evil. In some cases we can see this:
from physical evil, God brings forth moral good that otherwise
would not have come about; from moral evil itself we sometimes
see the greater good of penance, greater love of God, and so forth
arise; in other cases, we see that some evil men are the occasion
for good in others. However, there are also many instances where
we cannot see this: we only know that in ways unknown to us
God is able to draw forth good from evil. This is enough to break
down the force of the objection.
69. The creative intellect and the finality
of natural activities

We have seen, in the first argument for the existence of a First
Cause, that God is the First Cause of the activity of all created
beings. As First Cause, God cannot be caused by anything else in
any way, and so there can be no potency of any kind in Him.34
In other words, He is pure act. Consequently, God cannot be
material, for to be material involves the presence of a real po­
tency, namely, priman' matter. Hence, God is a nonmaterial
being, or, in other words, a spiritual being. Consequently, God
cannot be the source of activity after the manner of a material
being; He cannot cause activity by contact or gravitation or any
other material activity. Now, we have in ourselves the experience
of a principle of activity which is not itself moved by any type of
material motion, namely, our acts of willing.85 Hence, God is the
source of activity in created things by an act of will. But will
34 See below, sec. 73, the discussion of possibility.
’’This is discussed at great length in the philosophy of human nature.

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presupposes intellectual knowledge. Hence, God is an intellectual
being.
We have also seen that an effect cannot be more perfect than
its cause.30 But God is the cause of all contingent beings, and
so is the cause of men, who are intellectual beings. Hence, God
must be an intellectual being.
God, therefore, is the total cause of contingent beings, on
Whom the whole reality of these beings depends. And He is a
cause through intellect and will.
With these conclusions as a background, we can now complete
the analysis of finality, which we left incomplete in Chapter
VIII" We saw there that every agent acts for an end. We saw
also that there are two types of agents, those with knowledge and
those without it. Knowing agents foreknow the results of their
activities; and these results inasmuch as they are foreknown and
desired are in the full sense goals, or final causes. But how is the
end present, and how does it cause, in agents which do not have
knowledge?
We can derive some understanding of this from human activ­
ity. Human products are artifacts and are made for ends. This is
perhaps most clearly evident in machines. A machine is made for
an end; when it acts, it acts for that end, and its activity is de­
termined by that end. Of course, a machine is only an accidental
structure; the various substances in it are not human products
(even synthetics are products of nature-guided-by-man; they are
not purely artifacts ). God, on the other hand, is the creative cause
of the whole being, and so there is only a feeble analogy between
an inventor and the creator. But it helps us to see the causality
of the end. The end is a true cause of mechanical activity, in­
asmuch as it was foreseen by the inventor and desired by him,
and, by being a determinant of the mechanical structure, is a
determinant of mechanical activity. So, too, the end is a real cause
** See above, sec. 50.
87 See above, sec. 57.

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of the activity of noncognoscitive agents, inasmuch as it was fore­
seen and desired by the First, creative Cause of those agents, and,
by being a determinant of the intrinsic constitution of that nature,
is a determinant of natural activity.
When we studied final causality in the preceding chapter,39
we saw that it is possible for two causes to interfere with each
other’s activity'. Most often, such interference is negative in char­
acter—the effect is an accident, something less perfect, of a lower
order of being than either cause. And we saw that such interfer­
ence, since as such it does not produce new being, in the strict
sense of the word also does not require a cause. But we also saw
that occasionally the interference of two secondary causes may
bring about a positive effect which is different in kind from
either of the causes directly concerned. Such an effect—a chance
effect—is a real and positive reality. What is uncaused, at the
level of the causes immediately7 concerned, is the interference
itself. If another secondary cause brings about the interference
(for example, a man), we have called it an instance of "relative
chance,” for it is chance in relation to the immediate causes but is
finalized by the cause of tlie interference. We have also seen that
some interferences are not brought about by any7 secondary
cause at all—there is not only7 relative chance but real, irreducible
chance and contingency, namely, absolute chance.
At this point of our investigation (in the same chapter), we
asked ourselves whether tins analysis was sufficient, and we con­
cluded that it was not. Why? Because the causality of the cross­
interfering causes, as received in the patient, is such as to lead to
the production of a new being. Where is the finality by which
such a change leads to such a kind of being? Not in the process
itself, for the process is precisely that which is finalized. Not in
tlie new being, for it does not yet exist. Not in either or any of
the interfering causes, for the finality of their natural activity is
directed to a univocal and not to a chance (or equivocal) result.
Now that we know that there is a God, Who is an intelligent
w See above, sec. 57.

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being, and a cause by creation of natures, we have found an in­
tellect where the order of process to term is known and intended.
Hence, the unity and finality of positive chance results lies in
the order of beings as understood in the Divine Intellect.
Therefore, though on tlie one hand, as against determinista we
find and admit real, absolute chance and contingency in the ma­
terial universe, we cannot admit chance as a total and ultimate
explanation. In other words, there is chance, not merely in rela­
tion to some created agents but absolutely, even when all created
agents are considered. But chance is not total, for the finality of
the interference of causes and the order of process to term which
escapes the finality of any and all secondary causes is contained
within the finality known by the Divine Intellect, which is the
creative cause of tlie whole universe.30

70. Definitions
A per se ordered series is a group of objects which by their
very nature have determinate relations of priority and posterior­
ity. (For example, the series of natural numbers; the parts of a
real definition; the biological stages of a plant: seed, plant,
flower, seed.)
A per se ordered series of causes is a group of several causes
which by their very nature as causes depend on the next higher
in the group for their very character of being causes. ( For exam­
ple, principal and instrumental causes; knowledge and desire;
nerve impulse and muscle movement. )
Proof (demonstration) is a kind of mediate knowledge (rea­
soning) which because of the clear truth of its premises and the
explicit and full form of procedure leads to a certainly true con­
clusion.
Causal proof is one which not only establishes a conclusion as
true but shows why it must be so.
Fact proof is a proof which establishes that a conclusion is true
“For a summary statement of God’s causal relation to the world, see
Selected Passages, No. 29.

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without any reference to the ontological cause of the conclusion.
( For example, any proof of a cause from its effect. )
Analogy of participation is a non univocal similarity of two
analogates, one of which is by nature or essence (and therefore
wholly ) what the other is partially by received act.
Pure act is an act which is not the act of a potency, not a prin­
ciple, but subsistent and complete in its own order.
Total chance is a happening or being which is alleged to have
come to be without any determination from a final cause, in­
cluding the First Cause as well as all secondary causes.
71. Readings
St. Thomas Aquinas, Summa Theologiae, Pt. I, q. 2, arts. 1-3 (the
proof for the existence of Cod), q. 12, arts. 4 and 12 (the limits of
our knowledge of the Divine Essence); q. 13, arts. 1, 3, 4, 5, 11, and
12 (how we can name God).
E. F. Caldin, Science and Christian Apologetic, Aquinas Papers,
No. 17 (London, Blackfriars, 1951), pp. 18-21, on the proof for the
existence of God.
Etienne Gilson, The Philosophy of St. Thomas Aquinas, 2d ed. (St.
Louis, Herder, 1939), pp. 66-130.
------ Being and Some Philosophers, 2d ed. (Toronto, Pontifical
Institute of Mediaeval Studies, 1952), pp. 160-167, 172-179, on the
meaning of being and on existential contingency.
G. P. Klubcrtanz, S.J., “Being and God According to Contemporary
Scholastics,” The Modern Schoolman, Vol. XXXII (1954), pp. 1-17.
Jacques Maritain, The Range of Reason (New York, Scribner's,
1952), “A New Approach to God,” pp. 86-102; “The Meaning of
Contemporary Atheism,” pp. 103-120.
--------- Approaches to God (New York, Harper, 1954).
Pius XII, “Modern Science and the Existence of God," The Catholic
Mind, L, No. 1071 (March, 1952), 182-193. In tins address, the Pope
makes two points: first, that the modern science shows the mutability
(and therefore the contingence) of all material being, and secondly,
that the researches of modern science on the formation of the solar
system and the stars indicate (though they do not prove), that the
universe as we know it had an origin in tíme. These indications, how­
ever, are not yet of the nature of an established hypothesis, and, if
established, they would prove an absolute origin of the universe as
we know it; they cannot prove whether this absolute origin was pre­
ceded by another mode of material reality or whether this absolute
origin was an absolute origin of material being.

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A. D. Sertillanges, Foundations of Thomistic Philosophy, trans.
Godfrey Austruther (St. Louis, Herder, 1931), pp. 45-90; this author
stresses the “difference” in analogical predication so much that some­
times he seems to be an agnostic; he should be read according to his
intention, which is to follow and expound St. Thomas’s doctrine of
analogy.
Selected Passages from St. Thomas Aquinas

24. How We Can Know Cod at All
For we cannot know the essences of the separated substances by
demonstrative knowledge, for these essences are per se intelligible—
by an intellect proportioned to this. But it is not possible to gather a
knowledge of them from principles prior to them. But by speculative
knowledge we can know of them whether they are, and what they
are not, and something according to a likeness found in lower tilings.
Commentary on the Posterior
Analytics of Aristotle, Bk. I,
lect. 41.
Human reason is deficient in the knowledge of separated substances,
which nonetheless are most knowable in their nature. With regard
to the knowledge of them, our intellect is like the eye of the owl tc
the light of the sun, as is said in Metaphysics, II, and therefore it is
said in De Animalibus, XI, that about them we can know extremely
little by reason, although that little which we do know about them is
pleasing and dear to us.
Commentary on the Second
Book of the Sentences, dis.
3, q. 1, art. 3.

25. The Analogy of Participation
Only God is his own esse, existing, as it were essentially, that is,
inasmuch as his esse is his substance. This can be said of no other
being. For subsisting esse can be only one, as also subsisting whiteness
could be only one. Therefore, it is necessary that any other thing is a
being by participation, so that there is a distinction in it between the
substance partaking of esse, and the esse which is participated. But
everything which participates is like potency to act; consequently, the
substance of ever)' created being is related to its esse as potency to act.
Quodlibet III, art. 20.
There are two ways of predicating one thing of another: essentially,
and by participation. For light is predicated of an illuminated body by
participation; but if there were a separated light, it would be predi-

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catcd of that essentially. According to this, it must be said that being
is predicated essentially of God alone, because the divine esse is a
subsisting and absolute esse. But of any creature it is predicated by
participation, for no creature is its esse, but is something having esse.
Thus also God is called good essentially, because He is goodness itself;
but creatures are good by participation, because they have goodness;
for everything, inasmuch as it is, is good. . . . Whenever something
is predicated of another by participation, it is necessary that there
be something there besides that which is participated, and therefore
in every creature the creature itself which has esse is not the same as
its esse, and this is what Boethius says in his book. De Hebdomadibus,
“In everything which is, besides the First, esse is other than that
which is.”
But it is to be noted, that there are two ways of participating. One
way is, as being of the substance of that which participates, as the
genus is participated by the species. This is not the way that esse is
participated by the creature, for that is of the substance of a thing
which falls into its definition. But “being” is not of the definition of
any creature, for it is neither genus nor difference. But it is partici­
pated as not being of the essence of the thing. Hence, the question, "Is
it?” is a different one from, “What is it?” Consequently, since eveiything which is outside the essence of the things, is called an accident,
and so the Commentator says, on Metaphysics, V, that this proposi­
tion, "Socrates is,” has an accidental predicate, inasmuch as it signifies
the being of the thing, or the truth of the proposition. Now, it is true
that this term being, inasmuch as it implies the thing to which such
an esse belongs, in this sense signifies the essence of the thing, and is
divided into the ten genera, but not univocally, because esse does not
belong to all things in the same way, but it belongs to substance of
itself, but to other tilings in another way. If, therefore, there is in the
angel a composition of essence and esse, this is not a composition of
parts of substance, but as of substance and that which adheres to
substance. . . .
In reply to the second argument, it is to be said that esse is an
accident, not as if it were accidental to the thing, but as the actuality
of every substance. Consequently God, who is His own actuality, is
His own esse.
Quodlibet II, art. 3.
Although the esse of a thing is other than its essence, wc are not to
think that esse is something superadded after the manner of an acci­
dent, but it is as it were constituted by the principles of the essence.
Commentary on Aristotle’s
Metaphysics, Bk. IV, lect.
1 (cd. Cathala, No. 558).

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26. How God Is Distinguished from Creatures
A thing is said to be determinate in two senses: the first, by reason
of limitation; the second, by reason of distinction. But the divine
essence is not something determinate in the first way; only in die
second way. For a form is not limited except by this, that it is re­
ceived in another, to which the matter is proportioned. But in the
divine essence, there is not anything which is received in another,
because His esse is the subsisting divine nature itself. But such a
situation is not to be found in any other thing. For every other thing
has an esse which has been received, and thus limited, and hence it is
that the divine essence is distinguished from all others by this notbeing-receivcd-in-another. Thus, if there were a whiteness not in a
subject, by this very fact it would be distinguished from every white­
ness existing in a subject, although as whiteness it would not be
received and so not limited. Therefore, it is clear that the divine
essence is not something general in being, since it is distinguished
from all other things, but it is general only in causing, because that
which is by itself is the cause of all those things which are not by
themselves. Consequently, the per se subsisting esse is the cause of
every other esse received in another.
Quodlibet VII, art. 1, ad
1.
27. The Sources and Nature of Our Knowledge of God
First he shows what they knew about God, secondly, he shows from
whom they received this knowledge . . . thirdly, he shows how. . . .
For there was in them a true knowledge of God with regard to some
points, for “that of God which is known,” that is, which is knowable
about God by man’s reason, “is manifest in them,” that is, is manifest
to them by something which is in them, that is, by an intrinsic light.
We must therefore know that something concerning God is entirely
unknown to man in this life, namely, what God is. Hence, St. Paul
found at Athens an altar inscribed, “To the unknown God.” This is
because the knowledge of man begins with those things which are
connatural to him, that is, with sensible creatures, which are not pro­
portioned to represent the divine essence.
But man can know God from such creatures in a threefold way, as
Dionysius says. The first way is that of causality, for since such crea­
tures are able to cease to be and are changeable, it is necessary that
wc argue back to some unchangeable and perfect principle, and in this
way we know that God is. The second way is that of eminence; for we
do not go from all creatures to the first principle, as to a proper and
univocal cause, as for example, a man generated a man, but as to a
common and greater cause, and in this way we know that Cod is

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above all. The third way is that of negation, because, if God is a
greater cause, none of the perfections which are in creatures can per­
tain to God. . . . And in this way we say that God is unchangeable
and infinite, and anything else which is expressed in this way. And
this knowledge they had by the inborn light of reason. . . . Then
... he shows from whom such knowledge was manifested to them,
and he says that God manifested it to them. . . . Here we must con­
sider, that one man manifests to another, explaining his conception by
some external signs, for example, by word or by writing. But God
manifests something to men in two ways. First, by giving him an
internal light, by which man knows. . . . Secondly, by placing before
him exterior signs of his wisdom, that is, sensible creatures. . . .
Thus, therefore, God manifested to them, both by giving an internal
light, and by exteriorly showing sensible creatures, in which, as in a
book, the knowledge of God can be found.
Commentary on the Epistle
to the Romans, chap. 1,
lect. 6.
28. Meaning of “Substance" as Applied to God

God, absolutely speaking, is not an accident, but neither can He
with entire propriety be called a substance, both because the term
substance is derived from “standing-under [accidents],” and because
substance names the quiddity which is distinct from its esse. Con­
sequently, this [distinction of substance and accident] is a distinction
of created being. But if one does not insist on this, in an extended
sense of the term God can be called a substance (which is understood
to be above all created substance), in so far as substance has perfec­
tion, such as not to be in another and so on, and then it is identical
in the subject and predicate, as is the case with everything that is
predicated of God. . . . Consequently, because of the different mode
of predicating, substance is not used of God and creatures univocally,
but analogously.
Commentary on the First
Book of the Sentences, dis.
8, q. 4, art. 2, ad 1.
29. Relation Retween Creatures and God

For God is He by Whom all things arc, as by their efficient cause,
and for Whose sake all things arc, as by their final cause. For all things
are for Him, because they are for the sake of His goodness which is
to be communicated to them. And this was the reason which moved
God to produce things, and so ultimately, all things arc for God. . . .

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GOD, THE CAUSE OF LIMITED BEING

185

They are also effectively by Him. . . . Therefore He is the principle
and the end of all.
Commentary on the Epistle
to the Hebrews, chap. 2,
lect. 3.

30. How Different Names and Attributes
Can Be Predicated of God
Because God according to one simple act of existing is perfect in all
the ways which are indicated by the names we give Him . . . there­
fore these names positively belong to Him. . . . The intelligibilities
of the attributes are truly in God. . . . The plurality of names comes
from the fact that God is greater than our intellect. And the fact that
God is greater than our intellect, on God’s part, is because the fullness
of His perfection, and on our part, our intellect deficiently understands
Him. So it is clear that the plurality of those intelligibilities arises not
only from the side of our intellect, but also from the side of God,
inasmuch as his perfection is greater than every conception of our
intellect. Thus, to the plurality of intelligibilities there corresponds
something from the side of Gods reality—not indeed a real plurality,
but a full perfection because of which all these conceptions are suited
to him. ... On the side of our intellect, and also of the effects [from
which we come to know God] [something corresponds] because our
intellect cannot conceive the divine perfection with one conception
only, but needs many. . . . Therefore there is something in God which
corresponds to all these conceptions, namely, his full and every-sided
perfection, according to which any name signifying any of these con­
ceptions is truly and properly predicated of God.
Commentary on the First
Book of the Sentences, dis.
2, q. 1, art. 3.

CHAPTER X

The Transcendentais
72. Being is a transcendental

Some predicates1 can be said only of particular classes or kinds
of things, and these predicates are usually univocal ones; for
example, “white” (which can only be said of things that are ex­
tended); “square” (which can only be said of tilings that have
a surface). These predicates will be considered in Chapters XI,
XII, and XIII. But the predicates to be treated here are common
to many kinds of things, and so their communit)' must be one of
analogy, as we have already seen with regard to being and sub­
stance. A predicate which is not restricted to any category, type,
or class of reality, but goes beyond, or “transcends,” all limited
areas of reality and all distinctions within reality is called a “tran­
scendental.” The transcendcntals are predicates.
We have seen that is can be said or predicated of all real
things. From our study of being, which we know is common by
way of analogical inclusion, we can see that being is not a genus,
not even the widest possible genus. For genus is always abstract;
and the wider and more universal the genus, the more abstract
and potential it is. For example, material substance is a predicate
that can be applied to every thing in our material universe; it is
also a very abstract concept and is in potency to all the specific
determinations—living, sensitive, rational. But being as it is un1 The term “predicate” is here taken in a very wide sense to include
verb-predicates ( such as “runs,” "is" ) as well as nouns and adjectives. For
a discussion of those “metaphysicians” and logicians who wish to reduce all
two-eleinent propositions (de secundo adjacente) to threc-rleinent ones (de
tertio adjacente), see Etienne Gilson, Being and Some Philosophers, 2d cd.
(Toronto, Pontifical Institute of Mediaeval Studies, 1952), pp. 190-205.
186

[72]

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187

derstood in its first and proper metaphysical sense is named from
that which is most actual and concrete, namely, the act of exist­
ing. Being is not the “widest in extension and the least in com­
prehension,” because the logical rule of the inverse variation of
extension and comprehension holds only for universals. Being is
at once the widest in extension—for is can be said of all tilings—
and the fullest in (implicit) comprehension—for any real act or
perfection is. Being includes all reality; indeed, all the reality of
any and all individuals. Therefore, being (understood as “the
being of metaphysics”) is a transcendental.
This conclusion is simple and obvious. A series of problems,
however, remains. We have seen that is has many meanings and
that in addition to its strictly metaphysical meaning, it is also
used of things which are real only in the wide sense, and even of
purely mental objects. We must therefore also consider how these
meanings arc related to the metaphysical sense. Moreover, there
are some terms which arc used more or less in the same sense as
being, and so we should give a brief consideration to these terms.
Finally, some philosophers have raised a question about the sense
in which being is a transcendental. We will take up these topics
in inverse order.
The question, “In what sense is being a transcendental? ” is a
question about the unit}' of being.2 The question, "Is being one?”
has many meanings. It may mean, “Is there only one being?” and
immediate experience shows us many distinct individuals. The
question may mean, “Is being univocal?” The reflection which we
have made in Chapter III (and the following chapters) shows us
that being is analogous. The question may mean, “Is there only
one ‘kind’ of being, for example, material being or limited being?”
and a study of the being of metaphysics and of the proof for the
existence of God leads us to the conclusion that there arc many
kinds of beings, which are analogous with several kinds of anal*See above, Chap. II, sec. 12, nn. 23 and 27, and Chap. Ill, sec. 19, n.
3. St. Thomas explicitly says, “There is no single intelligibility in the things
which are said analogously” (Summa Theologiae, Pt. I, q. 13, art. 5).

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[72-73]

ogy (analogy of eminence in causality, analogy of proportion,
analogy of participation). The question may mean, “Granted
tliat beings as they are are many and analogous, can they be
correctly understood as beings by one concept?" An attentive
reflection on our knowledge of being has shown us that it is
impossible to have a concept of being in its first and proper
sense, and so the unity of being is not even of one concept.3
The community of the act of existing is only an analogical one,
and so being is one transcendental only by the unity of analogy
(according to all the kinds of analogy which we found in being).
We can now take up the consideration of the terms which have
somewhat the same meaning as being. One of these terms which
we have already used is “reality,” or "the real." As we have seen,
this is a term which belongs to the level of everyday, spontaneous
knowledge; hence, it is often used in a loose or less precise sense
than the term “being.” “Thing” as a term from the level of every­
day knowledge is like “reality.” As used on the level of demonstra­
tive knowledge, “thing” stresses the essence or quiddity and con­
notes the act of existing (whereas “being” includes the act of
existing more directly). “Something,” as a technical term on the
level of demonstrative knowledge, means the same as “thing," but
connotes, in addition, the division of that which is named “some­
thing” from other things. In other words, “something” is a term
which implies that there are other tilings in addition to the one
we call “something.” Hence, it implies the unity of the tiling (it
is a thing) as well as the diversity or multiplicity of tilings.
73. Possibles

As we have already noted, the properly real is being, that
which has an act of existing. Nevertheless, we understand that
some things can be in the real order which here and now actually
are not. We understand this from the contingent real tilings
which we experience. For these beings manifest themselves as
* For a more elaborate discussion of our knowledge of being, see below,
Chap. XIV, gee. 107.

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THE TRANSCENDENTALS

189

contingently existing. They are composed in the order of being
itself—namely, of an essence and an act of existing—and con­
sequently we can consider things in relation to existence even
though they are not.
When we consider a tiling inasmuch as it is able to be, we call
it a possible.4 A thing which is not, whether it be possible or a
mere fiction, is simply nothing in the real order. Such a thing,
under the aspect that it simply is not, is not the subject of any
form of knowledge at all. If we consider a thing as simply an
object of the mind, we are not thinking of a possible; we may be
thinking of a logical entity'; we may be studying the content of
dreams as a psychologist might do. If we investigate an essence
down to the last detail, but only from the point of view of what
it is, we are not dealing with a possible as possible and so are not
dealing with it from the point of view of the philosophy of being
—we may be engaged in mathematics or one of the sciences. But
when we consider an essence (a thing) inasmuch as some prop­
erly real thing can or could correspond to it, then we are con­
sidering the possible as possible, that is, in relation to being. A
possible considered in this way belongs to the subject of meta­
physics.
The intelligibility' of a possible, therefore, lies in its relation to
being. As a possible thing, an essence has the possibility of hav­
ing an act of existing; in other words, it is known as that to which
in the real order there could correspond a contingently existing
tiling.
Now, to understand an essence with a relation to an act of
existing there must be a foundation. This foundation is twofold:
(fl) in essence, and this consists in the noncontradictoriness of
the constituent elements of that essence; (b) in an act of existing
—not its own, of course, because a possible has no act of existing
4 By a “pure possible,” we mean something which docs not exist, but
is an object of knowledge with a reference to what could be extraniental.
We can also, however, consider the possibility of a being which exists; in
this case we arc not dunking about a possible in the strict sense of the
word (sometimes called a "mixed possible").

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[73-74]

—the act of existing of some actual cause, past, present, or future.
Hence, the intelligibility of a possible depends on its essence (un­
derstood with reference to an act of existing which a correspond­
ing real being might have); its possibility of being depends on
the act of existing of some cause ( or causes ) adequate to produce
an actually existing (real) being corresponding to the knowledge
we have.
Possibility', therefore, can readily be divided into two parts:
essential possibility (the noncontradictoriness or consistency of
its constituent intelligible notes, understood with reference to a
being which might exist), and existential possibility, for only
that can truly exist which exists necessarily of itself or is pro­
duced by an existing cause.
Because the possibility’ of being depends on a cause, and causes
can be proximate or remote and variously disposed to act, possi­
bility itself can have degrees. Moreover, because that which is
possible depends for its possibility on an actual being, a possible
can be said to be by an analogy of proportion—although the re­
lationship of a possible to an act of existing is mediate and indi­
rect—namely, through the esse of a distinct real being which is
its cause.
74. Beings of reason and pure intelligibilities

Whenever we think of something, that '‘something” can be
either a being in the proper sense of that term or some principle
of being or something pertaining to a being or sometimes not a
being in itself at all (for example, a fiction).5 All of these “things,”
however, can be considered as known, and as such they can be
called intelligible objects or intelligibilities0 (in the wide sense).
These intelligibilities, from the viewpoint of being, can be classed
into three groups: real beings, beings of reason, and pure intelli­
gibilities (rationes), that is, intelligibilities in the strict sense. So
* See Selected Passages, No. 32.
’ See Selected Passages, No. 33, especially par. 1, where intelligible objects
are divided into three classes.

[73-74]

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191

far in this book we have been considering mainly real beings, al­
though there have been occasional references to the other two
groups.
A being of reason is an object which can be thought of but
which does not and cannot exist in itself. Consequently, in the
proper sense of being, such objects are simply not beings. Never­
theless, they are understood after the manner of beings. They are
objects conceived or mentally constructed with reference to the
real order; yet they have no direct correspondent in that order.7
Beings of reason are of three kinds. ( 1 ) Negations and priva­
tions (for example, “nobody,” “a hole”; “blindness,” "ignorance”)
obviously do not correspond to any real existent or to any real
principle of being. A negative or privative proposition may be
true or false, yet the truth of a negative proposition does not im­
ply tlie existence of a negation. (2) Relations of reason are beings
of reason, either because they join together objects which exist
only in a mind (for example, the relations of genus, property',
subject and predicate) or because they are mentally applied to
real beings without a direct and a real foundation in tlie real, for
example, tlie “right” side of a bible (transferred to tables from
the distinction between the sides of an animal body), the “top”
of a box whose top and bottom arc constructed tlie same, and so
forth. (3) There are also mental constructs which are beings of
reason, because as such they cannot exist, and are only indirectly
related to the real, that is, through some other real being from
which the construct is derived. Among such constructs there are
to be found some second-level abstractions (for example, “hu­
manity,” which, although it is understood after the manner of the
substantial form of a being, is rather the abstracted formal intelli­
gibility' of “man,” which is the product of a total abstraction) and
some transferred intelligibilities.8
’See Selected Passages, No. 31.
• For example, many metaphors like "John Doe is a pig,” where we under­
stand John Doe’s greediness in terms of the understood nature of a pig.
In such metaphors, we attribute an alien nature to the subject. The “pig”
we are speaking of is not an existent individual (for such a predication

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Beings of reason are beings because that is the way we think
of them. They are understood as having the nature of being. Be­
cause beings of reason are correlative with the real on which they
are modeled, the predication is by proportion; because beings of
reason are not intrinsic constitutive principles of being but are
understood after tire manner of beings, tlie analogy is not intrinsic
but extrinsic. Hence, we may say that beings of reason are by an
extrinsic analogy of proportion.
Why do men produce or invent beings of reason? For the pur­
pose of a better understanding of, and a more efficient dealing
with, real beings. For example, consider how awkward it would
be to think and talk of ‘'digging a hole,” “curing an illness,” “being
in debt,” without making use of any beings of reason. Again,
consider the poverty of our literature if all metaphors were re­
moved from it. Thirdly, our direct (or ontological) understanding
of beings is frequently very limited. There are many tilings which
we cannot directly understand in themselves, particularly as soon
as we get beyond immediate experience into science. ( To say that
science makes use of constructs is by no means derogator}' to the
dignity of science; in a way it is a glorification of the human
mind, for although the human intellect is limited by being the
intellect of a rational animal, it can at least to some extent tran­
scend its limitations by means of the products of its own ac­
tivity.)®
Besides real beings and beings of reason, there is a third class
of intelligibilities, the pure intelligibilities.10 Universals, for exam­
ple, are pure intelligibilities: they arc neither merely constructed
mental objects nor real beings. With regard to universals, we
must distinguish between that which is known and the manner in
would be false); nor is it a being of reason (for beings of reason cannot be
directly predicated of existents like John). See above, Chap. HI, n. 8, and
tlie article there cited.
* For a fuller discussion of the nature of constructural knowledge and its
difference from ontological knowledge, sec below, sec. 100.
*” See also, Selected Passages, No. 33, for a very full explanation of what
an intelligibility is.

[74-75]

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193

which the known is in the mind. “Man,” for example, can lx
*, truly
said to be the knowledge of a real being, because that which wc
know when we know “man” is wholly and entirely real. But the
manner in which we know “man”—namely, as abstract and uni­
versal—is unlike the manner in which a man exists—namely, as
concrete and singular. Similarly, many of the objects which we
speak of in metaphysics are pure intelligibilities. To see the differ­
ence between a pure intelligibility and a being of reason it may
help to compare two conceptions. As an example of a pure intelli­
gibility we will take the act of existing of a being with respect to
what is known when we know it. This act is real (for it is that
principle in a being by which it is); but with respect to the man­
ner in which it is known, it is not immediately real (since it is
known as if it were a subject). As an example of a being of rea­
son, we will take the concept of existence,11 namely, “the form by
which a real being is.” Existence is a positive formalization, to
which no being or principle in the real order directly corresponds.
In the real order, there is the esse of some being. This esse is
referred to indirectly by the concept “existence.” The mind con­
structs and conceives, after the manner of a form, a substitute
representation of a real intelligible which in itself is not essential
or formal. In other words, the mind essentializes and formalizes
by way of a construct (derived from a real principle) what it
recognizes in the real as belonging to the existential order.
75. The transcendental “one”
The term “one” is used in two quite different senses. The nu­
merical “one” is used in counting and, at the level of demonstra­
tive knowledge, in arithmetic. At present wc are not going to deal
with the numerical “one” at all. The transcendental “one means
“actually undivided”—for example, in the expression, “in one
11 For the difference between the “concept of existence,” which is a constructural concept, and the “conception of the act of existing,” which is a
direct intelligibility, see above, sec. 12, n. 2-3, 27; sec. 19, n. 3, and below,
sec. 107; see also, G. P. Klubertanz, The Philosophy of Human Natura
(New York, Appleton-Century-Crofts, Inc., 1953), pp. 179-180.

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[75-76]

piece.” The transcendental ’’one” is an absolute adjective; it does
not in any sense imply that there are other things. In form, it is
a positive term; but as far as its meaning is concerned, it is nega­
tive, for it means “not actually divided.” Terms related to “one”
are “unique,” which means “one and only one”; “whole,” which
implies that the thing which is actually undivided is capable of
division into parts; and “simple,” which means “not only undi­
vided but indivisible, having no parts.” 12
“One” is the first “property”18 or attribute of being. It is the
first property, because it refers to being absolutely, considered in
itself (and so is prior by nature to the other transcendentals
which belong to being relatively, as we shall see). “One” does
not add anything positive to being; it is tlie being in itself which
is undivided. However, we understand this absence of division
after tlie manner of an added qualification.
Everj' being is one. For a being is either simple, that is, indi­
visible and so, of course, actually undivided, or it is composed.
But parts do not make up a being unless they are united in some
way or other. And there are a number of kinds of unity.
ONE

per se

according to one act of existing14
according to one essence (nature)

per accidens

by composition of substance and accident (or
two accidents, according to their inherence in
the same substance)

accidental

of many substances according to some accident:
dynamic: joined in operation (activity)
static: joined in place, structure, and so forth

“ See also, Selected Passages, No. 34.
” From tlie Latin, proprietas or passio entis.
14 Ordinarily, both these types of per se unity are found together, for
the undividedness of essence and of the act of existing are naturally pro­
portioned to each oilier. Hence, for many purposes, that can be said to
be “per se one” which has one essence or nature. But it is still the un­
dividedness of the act of existing which is the most basic reason for
denominating a being one being.

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195

“One” and “being” are clearly not synonyms. On the other
hand, they clearly do not refer to really distinct principles.
Hence, there is a distinction of reason between “one” and “being.”
Moreover, since “that which is actually undivided” is a being,
and a being is actually undivided, the distinction between “one ’
and “being” must be a minor distinction of reason.10
The opposite of “one” is “many” or “the divided” or “tlie dis­
tinct” or “the different” or “the diverse.” Which one will be pre­
cisely the opposite of “one” in any given case depends upon the
precise connotations in the particular usage of “one.”

76. The transcendental “true”
In logic and the theory of knowledge there are many references
to “truth.” There, “truth” means the “conformity of the mind to
things" and, when we are speaking accurately, should always be
called logical truth. So, too, when we ask whether something is
true, we are ordinarily speaking of logical truth. And we use
“falsehood” or “falsity” in the same kind of way. However, even
in our ordinary speech, we occasionally use the term “true” and
especially “false” in a related but quite different sense, as in the
expressions “false teeth,” “true love,” “a true albino.” In this sense,
we arc talking about tlie conformity of the thing to its definition,
essence, and so forth, or, more generally, to knowledge or a mind.
(Compare the meaning of the verb “to true.”) This is the sense
in which we speak of the true in metaphysics, namely, the con­
formity or conformability' of a thing to a mind.
The true is not a negation or a negative attribute, for it ex­
presses something positive, namely, conformability with intellect.
But “true” does not add anything really distinct to “being,” for
“true” is simply' “being” expressed in its relation to intellect.
Hence, the distinction between ‘being” and “the true” is a minor
distinction of reason.
When we say, “The true is being in relation to intellect,” we
must determine explicitly' which intellect we are referring to.
“See above, sec. 25.

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Since the beings of our experience, by their very participation in
being, are related to the First Being, it is to the Divine Intellect
that the true has an essential relation. Because the beings of our
experience exist by creation and God creates through intellect
and will, all created beings aie actually conformed in their being
to the Divine Intellect. The predicate true, therefore, when ap­
plied to creatures, means “made so as to conform to the Divine
Intellect.” When applied to God Himself, however, the predicate
true means essentially that God, Who is a subsistent intellect and
act of understanding, knows Himself so perfectly that what He is
and what He knows of Himself are entirely and completely iden­
tical.
But in addition to the Divine Intellect there are also other,
contingently existing intelligent beings; and, of these, we are es­
pecially concerned with man. Note that only those beings are
necessarily conformed to the human intellect which come into
being in dependence upon a human agent. In the case of artifacts,
true means “made so as to conform to the artist’s mind.” In the
case of all other finite tilings, however, there is no necessary rela­
tion of actual conformity to the human intellect. Some things are
in fact known by man. With regard to the nature and existence of
these things, it is extrinsic and accidental to them that they be in
fact known by some man. Therefore, true in the sense of “actually
conformed to a human mind,” when applied to artifacts, is an es­
sential predicate; when applied to natural beings, it is an acci­
dental and extrinsic predicate.
The relation between being and the human intellect can lie
considered in terms of conformability rather than conformity. By
this we mean that whether such things are known or not, they
can be known, they are knowable. The relationship of conform­
ability to some created intellect is a necessary one, given the
existence of these things and of an intellect, but it is secondary
(the primary essential relation is to the Divine Intellect). The
relationship of conformability to any given individual created
intellect or to any kind of created intellect—for example, that of

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197

man—is contingent or accidental, for it is not necessary that men
exist. Applied to creatures, therefore, the term “true” in the sense
of conformability means that they are such as can be known by
man. Some things, of course, arc here and now not actually
knowable by man—things hidden from man’s experience within
the earth or at the far reaches of the stellar universe or among
the multitude of angels. But the reason these things cannot be
known at present is some hindrance external to the nature of the
things—their lack of contact with us, for example. Hence, we can
state what is sometimes called the “principle of intelligibility"—
"All things are intelligible."
We can also ask whether the predicate true in the sense of con­
formability to the human intellect can be applied to God. Prior
to our knowledge that God exists we cannot, of course, say that
He is true. But now that we know that He exists, it is evident
that He can be known by man.
True, in the sense of conformability to some created intellect,
is a necessary but secondary predicate of all things. In the sense
of conformability to some particular created intellect or to some
kind of created intellect, true is an accidental and extrinsic predi­
cate.
According to the various meanings of true which we have been
considering, it is a relative attribute: it describes a thing as re­
lated to something else (namely, an intellect). In other words, it
denominates a thing from something distinct from it (an intel­
lect), to which it has a relation.10 Does true have any absolute
signification? In other words, does it say anything about the being
in itself? Yes, because a being to be conformed and conformable
to intellect must be of a certain kind. Intelligibility supposes that
being has a certain structure. We have previously seen that po­
tency, as such, is not knowable in itself but through act and in
relation to act.17 We have also seen that the first and primary’ of
Recall what was said above, that the relation in question is not some­
thing added to being; it is only rationally distinct.
"See above, sec. 40 (4).

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all acts is the act of existing. Hence, the primary one among the
absolute meanings of true is the one which designates the act of
existing of a thing:18 “The true is the esse of things/’ On this
basis we can see why every being is true. For being is “thatwhich-is,” “something having an act of existing.” The act of exist­
ing is intelligible, even if we cannot have a simple apprehension
or direct abstractive concept of it. At the very least, we can know
in a judgment that a being is. This does not imply that every
being is perfectly or completely intelligible to man; it only means
that no being is completely unintelligible to man. Therefore, true,
in its first absolute meaning, designates the basic internal actual­
ity of a being, its act of existing.
Moreover, act is also form, especially substantial form. Hence,
a second absolute meaning of transcendental truth is the actual
possession of a form and, consequently, of a nature. Again, inas­
much as act is intelligible, the being which possesses an act—
that is, a form—is thereby intelligible. Here, however, not all
beings are equally true, that is, equally conformable to the human
intellect. Sensible things can be directly known by us. But pure
forms—the angels and God—cannot be directly known in them­
selves to the human mind, because it is impossible for us to have
an abstractive concept of such forms. Therefore, true, in the sec­
ondary, absolute sense of the possession of a form or nature, can
be predicated of all beings, but in different ways of sensible
tilings, separate substances, and God.
Hence, we can sum up the entire discussion of transcendental
truth in this way. The transcendental true is analogous. First,
there is the subsistent truth of God Who is pure act, perfectly
known to Himself. Then there are the participated truths, which
are primarily true inasmuch as beings by participation arc con­
formed to the creative intellect, and secondarily true, as such
beings arc conformable to some created intellect. In a derived
St. Thomas most often gives among the "absolute" meanings of the true
the esse of things; but there are also other meanings; cf. for example,
“veritas humanae naturae," in Summa Theologiae, Pt. Ill, q. 5, arts. 1 and
2.

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sense, true designates the absolute (that is, nonrelative) perfec­
tion of a being, and here, too, there are degrees of truth. That is
most true which is pure, subsistent act. That is more or less true
which has more or less of act—primarily the act of existing, sec­
ondarily other acts, especially substantial form and essence.
The opposite of the true is the false. Being is not, absolutely
speaking, false, for that which has, absolutely speaking, no act of
existing in any sense is not a being. However, a being may be
called false from some limited point of view. For example, when
we speak of “false teeth,” we mean “some things which are not
really teeth, but have something of the appearance of teeth and
perform some of their functions.”

77. The transcendental “good”

The predicate “good” is used in many ways. In its unqualified
sense (for example, “John is a good man”), it means “that which
is perfect according to its kind.” In this sense of the term “good,”
the goodness of a thing is proper to it; and the goodness of one
kind of thing is different from the goodness of another kind. For
example, a pen is good when it writes well; a race horse is good
when it runs fast; a man is good when he has the virtues and
other qualities which human nature ought to have. The un­
qualified “good” is therefore also called the “proper good.” The
proper good is clearly not possessed by every thing, for there arc
bad men, bad bargains, bad food. Moreover, in the beings of our
experience, their proper good is a perfection distinct from their
substance and so is an accidental perfection. (The proper good
of man is studied in ethics or moral philosophy. )
The opposite of the proper good is the evil. Taken concretely,
“evil” or “bad” designates some thing which is without ( deprived
of) some particular good which it should have according to its
kind. Taken abstractly, “evil” or “badness” is the privation1® itself;
" Distinguish between privation and the simple absence of something.
Privation means “the absence of something which is due. or suitable, or
necessary.” On evil as a privation, see Selected Passages, No. 36.

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and privation itself is not a real being (just as blindness is not a
being) but a being of reason. An evil thing, of course—“evil
*
taken concretely—is a real being, real with the reality of the
thing that lacks a good which is due to it according to its nature.
But goodness and evil are not simply absolute predicates, like
perfect and imperfect. In the full sense of the term “good,” a
thing is good when it is not only perfect in its kind but is at the
same time an object of appetite, or tendency. Good food, for ex­
ample, is not merely a material substance with all the accidents
suitable to its nature but also one which corresponds to a par­
ticular appetite, namely, the biological tendency of a living thing
toward that which nourishes it. Similarly, a good race horse is
not merely one which exercises the particular activity of running
rapidly; that activity is also desired by someone. Again, a good
man is not merely one who has certain virtues; he has the virtues
he ought to have—and ought expresses the basic natural tend­
ency of man to be in the condition of possessing such virtues.
These examples—similar ones can easily be found—show us that
good is a perfection for which there is an appetite (tendency)
either in the thing itself which possesses or is capable of possess­
ing the perfection or in something else. The goodness of a means
inasmuch as it is purely a means is derived entirely from its rela­
tion to the good as just described.
The purpose of this analysis of the proper good has been to
help to clarify the question, Is every being good? Is good a tran­
scendental? Obviously, these questions cannot be asked about
the proper good, since it is a fact of immediate experience that
there are evils. We must therefore be asking a question about
good in some different, even though related, sense.
A tiling is unqualifiedly good when it has the perfections
proper to its nature or essence and, as so perfected, is the object
of some tendency. Suppose, instead of asking about the perfec­
tion suited to tlie nature (whether accidental or substantial) of
a thing, we ask about the perfection of a being as being. Is every
being good inasmuch as it is (a being)? In asking this question,

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201

we are asking about the qualified good—that is, about the good
with the qualification, ‘inasmuch as it is (a being).” 20
We have seen that God is by His essence; He is the pure and
subsistent actuality of being. So it follows that He is absolutely
perfect as being. Because lie is an intelligent being, He also has
an intellectual appetite. It is only natural that His own infinite
perfection should be an object of this intellectual tendency, and,
therefore, the infinite perfection of God is also infinite goodness.21
“Infinite” goodness means goodness without limit, without flaw.
We have seen that God is the cause of the world by creation,
through intellect and will. It follows at once that creatures can
be named good through the analogy of eminence in causality. Is
the goodness of creatures as beings merely an extrinsic denomina­
tion,22 or is it also an intrinsic perfection? Recall that the relation
in being between God and creatures is proved to be an intrinsic
analogy of eminence in causality and, therefore, also the analogy
of participation. Since God is good inasmuch as He is by His
nature, whatever participates in being also and to that same de­
gree participates in goodness. And since every being is either
being by essence or being by participation, every being is good.
This answer to the question, “Is every being good?” has been a
priori.28 It is possible to approach the transcendental goodness of
”011 the transcendental good, see Selected Passages, No. 35.
“ Since the nature of God is identically the act of existing, the transcen­
dental goodness of God is identically His proper goodness. And since Cod
is an intelligent being. His proper goodness is also moral goodness. This
identity of perfection is not found in any other being.
““Extrinsic denominations” will be treated more fully later on, hi secs.
94 and 95. Here, it will suffice to define extrinsic denomination as “a name
and a conception truly applied to one being because of another.” Hence,
it is evident that an extrinsic denomination is not a real being: it does not
designate an intrinsic or inherent perfection or act. It is an intelligibility.
“The a priori approach to transcendental goodness is not in conflict with
the truth previously stated that we have no direct, immediate knowledge of
God, that we know Him only through creatures. For in the a priori ap­
proach as it is used here, we do begin with an immediate experience;
namely, the experience of proper goodness. From this, by way of analogy
and negation, we proceed to find transcendental goodness in the fullness of
being, which is also an object of tendency.

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creatines directly, and this second approach is necessary for a
full understanding. Let us repeat that the good is an act or per­
fection which is the object of some tendency. Every being, in
order to be, has at least an act of existing, and by this esse the
being is a being in act. Furthermore, even' being in some sense
clings to its own actuality and resists destruction more or less,
according to its nature. The tendency of every being to continue
in being is evident in living things, particularly in men. One’s
own death is feared and disliked; even those who voluntarily
choose suicide do so under the impression that it is the lesser of
two evils. Plants and animals resist death in ways proportioned
to their nature and will work very' hard to keep themselves alive
for their normal life span (whether this be a few hours or hun­
dreds of years). Nonliving things, too, in their way resist destruc­
tion, again more or less according to their particular nature. The
impulse to self-preservation is based on the order of actualized
potency to its act; more concretely, on the order of actualized
essence to the act of existing. Since every being strives to keep
itself in act, since being as actualized has a perfection, every
being inasmuch as it is is good.
Moreover, there is an order among created beings such that
some beings are for others. With regard to very many beings, we
know what beings are goods for them, as we have seen above in
studying tendency and final causality. Hence, inasmuch as a cre­
ated being is both perfective of another and the object of the
other’s tendency, it is good. However, wc do not sufficiently know
the order of created beings to each other to use this order as an
evidence to show that every being is good.
What is the relation of the transcendental good to being? The
transcendental good is being inasmuch as it is. Consequently,
good is not something really distinct from being and added to
being but in the real order is identical with being itself. But the
conception, good, is not identical with the conception, being, for
the very intelligibility of good adds to being the relation to some
tendency or appetite. Therefore, the transcendental good adds to

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being the relation to appetite and so is distinct from being by a
minor distinction of reason.
78. The beautiful24
The way in which we approach the beautiful must be some­
what similar to the way in which we studied the good. Some sen­
sible things are beautiful; others are not. The beauty of one kind
of thing is not the same as the beauty' of another; the beauty' of a
sunset is not that of a tree; the beauty of a sun-drenched land­
scape is not that of a painting; the beauty' of a poem is not that of
a building. Yet in all cases, proper beauty has a common descrip­
tive note: it is that which pleases when perceived. An analysis of
tlie beautiful object shows at least these elements: an ordered
multiplicity and a certain excellence of form and cognoscibility.
The experience of beauty also has some common elements: it is
both cognoscitivo and affective; the type of knowledge involved
is akin to contemplation; the type of attitudinal response is rest
in the possession by knowledge. Hence, the beautiful seems to
be related to both knowledge and appetite, to both intellect and
will.
Is there also transcendental beauty'? Is every being beautiful
inasmuch as it is? Every' being, inasmuch as it is a being, pos­
sesses actuality; all finite beings are made up of an ordered mul­
tiplicity' of “parts” or principles—whereas God, Who is the simple
actuality of existing, with regard to our knowledge of Him is a
virtual ordered multiplicity of unified perfections; every being
has at least some splendor of actuality, be it only the act of exist84 The study of the beautiful in an introductory book must necessarily be
brief.
There are also some analogous perfections (like life, knowledge, under­
standing, willing), which are similar to the transcendental^. These perfec­
tions are not strictly transcendental, for they are not found in all beings,
and are not "properties” of being as being. Their similarity lies in their
analogy. In its analogous sense, “life” is a .special way of existing; knowl­
edge, understanding, and willing are special ways of acting immanently.
Note, however, that life, understanding, and willing are also used in uni­
vocal senses. These differences are explained in the philosophy of human
nature.

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ing; and ever}’ being can be related to both knowledge and appe­
tite, and in some way we can take pleasure in the knowledge of
it. This is the a posteriori approach to transcendental beaut}'.
The a priori approach to transcendental beaut}' is richer and
fuller. We find beauty in created things, and in them beauty is
a perfection without any intrinsic limitation or imperfection.
Hence, God, the creative cause of all being, must also be beauti­
ful. And any perfection predicated of God must be predicated
infinitely, without any limitation, and as identical with His es­
sence and act of existing. Hence, God is subsistent beauty,
beauty by essence, infinite beaut}' inasmuch as He is. Therefore,
all His creatures, which are beings by participation, also possess
transcendental beauty by participation. Therefore, every being is
beautiful inasmuch as it is, either essentially or by participation.

79. Definitions
A transcendental is a “predicate” and a perfection which tran­
scends all genera and differences.
Tiling (as a scientific term in metaphysics) is that which has
an essence or quiddity, and, only by implication, an act of ex­
isting.
Something is a thing which is distinct from other things.
A possible is something which could lie or could have been.
A being of reason is an object (an essence or form) whose
actuality is the act of being-understood, which, as such, cannot
have an act of existing (in the proper sense of that term) but
which is understood after the manner of a being.
An intelligibility (in Latin, ratio) is that which the intellect
understands of tire meaning of some term. (Tin's is a purely de­
scriptive definition.) In the strict sense, an intelligibility is neither
a being of reason (for what is understood exists), nor a real being
(for it docs not exist in the way in which it is known).
The transcendental one is that which is actually undivided.
Simple is that which is undivided and undivisible, that which
has no parts.

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Whole or composite is that which is actually undivided but can
be divided, that which has real parts.
Per se one is that which is one of itself, not by an external
principle.
Per accidens one is that which is one by inherence.
Accidental one is that which is substantially many and is one
by some distinct accident.
Logical truth is the conformity of the mind to the object.
Transcendental truth (ontological truth) is the conformity or
the conformability of being to knowledge.
The good is that which is desirable. (This is the preliminary,
descriptive definition.)
The proper good is some actuality or perfection in relation to
the appetite of a certain kind of being.
Trascendental goodness is the actuality or perfection of a
thing inasmuch as it is the object of some tendency.
Evil, taken concretely, is a being deprived of some particular
good.
Evil, taken abstractly, is the privation of a particular good in a
subject apt to have that good.

80. Proofs (to be completed)

A. Every being is one.
B. Every being is true.
C. Every' being is good.
81. Readings
St. Thomas Aquinas, Summa Theologiae, Pt. I, q. 11, arts. 1 and 2
(on the meaning of transcendental unity' and its relation to multi­
plicity), q. 16, arts. 1-6 (on the various meanings of truth, its relation
to being and to God), q. 17, arts. 1 and 4 (on falsity and its relation
to truth), q. 5, arts. 1-5; q. 6, arts. 1-4 (on goodness, its relation to
being; the goodness of God and of creatures); Pt. I-II, q. 94, art. 2
(on the relationship of the various transcendentals, and the analytical
[logical] priority of being); On the Power of God, q. 7, art. 11, ad 2
(on the order of the transcendentals to each other); Truth, q. 1, art.
1 (the meaning of truth); q. 21, arts. 1 and 2 (the meaning of good

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and its relation to being); Contra Gentiles, Bk. Ill, chaps. 18, 19, 20,
and 24 (good and the will; relation between good and final cause).
St. Augustine, Confessions, Bk. 10, chaps. 27, 33-34 (some passages
on beauty).
Clifford G. Kossell, S.J., “Principles of St. Thomas’s Distinction be­
tween the Esse and Ratio of Relation," The Modern Schoolman, XXIV
(1946), 28-36; an excellent exposition of what is meant by an “in­
telligibility.”
Jacques Maritain, Art and Scholasticism, trans. J. F. Scanlan (New
York, Scribner’s, 1930), pp. 23-38, 167-172, 161-166; the first two
selections deal with beauty and its characteristics; the third with the
perception of the beautiful.
Selected Passages from St. Thomas Aquinas

31. Substance and Accident Contrasted with Beings of Reason
. . . the quasi-definition of “being” is “something having esse.” But
substance alone is that which subsists. Accidents, however, are called
beings, not because they are, but rather because by them something is;
as “whiteness" is said to be, because its subject is white. Hence,
[Aristotle] says that accidents arc not simply called beings, but beings
of being, such as quality and motion.
Nor is it to be wondered at, that accidents are called beings though
they are not beings simply, because even privations and negations are
said to be somehow beings, as “not-white is,” not because not-white
has an act of existing, but because a subject is deprived of whiteness.
This, therefore, is common to accidents and privations, that being is
applied to them by reason of their subject. But they differ in this, that
the subject has esse to some extent according to accidents, but accord­
ing to privations it docs not have esse in any sense, but rather is
deficient in esse.
Commentary on Aristotle’s
Metaphysics, Bk. XII, lect.
1 (ed. Cathala, Nos. 24192420).

32. The Difference Between Being and Being-known
It is clear to anyone who carefully considers the arguments of
Plato, that he arrived at his erroneous positions, because he believed
that the manner of being of the thing understood is like the manner
of understanding the thing . . . But this is not necessary. For even
if the intellect understands things by this, that it is like to them as
far as the intelligible species (by which it is put into act) is concerned;
yet it is not necessary that this species be in the intellect according to
the way in which it is in the thing understood. For everything which

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is in a subject, is, according to the manner of the subject in which it is.
Therefore, on account of the very nature of the intellect, which is dif­
ferent from the nature of the tiling understood, it is necessary that
the mode of understanding by which the intellect understands be dif­
ferent from the mode of being by which the thing exists. For, though
that which the intellect understands must be in the thing, it need not
be there in the same way.
Commentary on Aristotle’s
Metaphysics, Bk. I, lect. 10
(ed. Cathala, No. 158).

33. The Meaning of “Intelligibility”
There arc three ways in which things are signified by words. For
there are some things which according to their entire and complete
being are outside the mind, and these are complete beings, like "man"
and “stone.” There are other things which in no way are outside the
mind, like dream-objects and the image of a chimera. There are still
other things which have a foundation in reality outside the mind, but
the completion of their intelligibility, with regard to what is formal
in them, is by the operation of the mind, as is clear in the universals.
For “humanity” is something in reality, but does not have the nature
of a universal, since there is no humanity common to many outside the
mind. But in the way “humanity” is present in the intellect, there is
joined to it an intention [“intention” here means “a note or charac­
teristic added to the understood form ‘humanity’ because of the latter’s
relation to many things”], according to which it is called a species.
Similarly, “time” has a foundation in motion—namely, what is before
and after in the motion itself—but with regard to what is formal in
time—namely, the measuring [of duration or motion]—it is completed
by the operation of the intellect which measures. I make the same dis­
tinction with regard to truth. Truth has a foundation in the thing, but
its intelligibility is completed by the action of the intellect—when,
that is, the thing is apprehended in the way it is. Therefore, the
Philosopher says [Metaphysics, Bk. VI, 1027b26] that the true and
the false arc in the mind, but good and evil are in things. Now, in the
thing there are its essence and its esse; truth is founded rather on the
esse of the thing than on the essence. As the name “being” is given to
something from the act of existing, so in the operation of the intellect
which takes the esse of the thing as it is (by becoming like to it), the
relation of equality is completed, and the intelligibility' of truth con­
sists in this relation. Therefore, I assert that the very esse of the thing
(as it is in the knowledge of the intellect) is the cause of truth.
Commentary on the First
Book of the Sentences, dis.
19, q. 5, art. 1.

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An intelligibility (ratio), as it is taken here, is nothing other than
that which the intellect understands of the meaning of some name.
In those things which have a definition, the intelligibility is the defini­
tion itself, as the Philosopher says, "The intelligibility signified by the
name is the definition” (Metaphysics, Bk. IV, 1012a25). But some
things have an intelligibility in the present meaning of the term, which
have no definition, as (for example) quantity and quality and similar
things, which are not defined, because they are the most general
genera. Yet, the intelligibility of quality is that which is signified by
the name “quality,” and this is that by which quality is quality. Hence,
it makes no difference whether the things which are said to have an
intelligibility have or do not have a definition. Thus, it is clear that the
intelligibility of wisdom which is predicated of God, is that which is
conceived as the meaning of this noun, although the Divine wisdom
itself cannot be defined. Yet the noun intelligibility does not mean the
conception itself, for this latter is signified by the noun “wisdom,” or
by some other name of a thing, but it signifies the intention of this
conception, just as the noun definition signifies an intention, and so
also other nouns of second imposition.
From this it is clear . . . how an intelligibility is said to be in
reality. For this does not mean that the intention which we signify by
the noun intelligibility, is in reality, nor even that the conception to
which this intention applies is in reality outsde the mind—since it
is in the mind as in its subject—but it is said to be in the thing,
inasmuch as in the thing outside the mind, there is something which
corresponds to the conception of the mind, in the way in which that
which is signified corresponds to its sign.
Commentary on the First
Book of the Sentences, dis.
2, q. 1, art. 3.
Cf. Responsio ad F. Joann.
Vercellens. de art. 108, a.
1.

34. The Transcendental “One”
“One” ... is used in two senses. In one way, inasmuch as it is
convertible with being, and thus, ever}' thing is one by its essence
. . . and “one” does not add anything to being except only the in­
telligibility of “being undivided.” In the second way, “one” is used,
inasmuch as it signifies the intelligibility of the first measure, cither
simply, or in some genus.
Commentary on Aristotle’s
Metaphysics, Bk. Ill, lect.
12 (ed. Cathala, No. 501).

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For “one” which is convertible with being designates being itself,
aciding the intelligibility of indivision, which, since it is a negation or
a privation, docs not posit any nature added to being. And thus “one”
in no way differs from being in reality, but only in intelligibility. For
negation and privation are not beings in the real order, but beings of
reason.
Commentary on Aristotle's
Metaphysics, Bk. IV, lect. 2
(ed. Cathala, No. 560).
He says, therefore, that “one” is said to be per sc and per accidens.
And he shows that we must consider the per accidens one primarily in
singular terms, and this in two ways. In one way, there is a per
accidens one, according as an accident is compared with a subject;
in the other way, according as one accident is compared with another.
In both cases, there are three things to consider: one composite, and
two simple principles. For if we take the one per accidens according
to the comparison of an accident to a subject, we have, for example:
first, Coriscus, second, “musically-inclined,” third, “the musicallyinclined Coriscus." And these three are one per accidens, for “Co­
riscus" and “musically-inclined” are one in subject. Similarly, when
we compare an accident to an accident, there are three things: of
which the first is “musically-inclined,” the second “just," the third, the
“musically-inclined, just Coriscus.” And these examples are said to one
per accidens, but in different ways.
For "just” and "musically-inclined,” which are the two simple
principles in the second way, are called “one per accidens,” because
they happen to one subject. But “musically-inclined” and "Coriscus,”
which are the two simple principles in the first way, are called one per
accidens, because “one of them,” that is, “musically-inclined,” happens
to the other, that is, Coriscus.
Commentary on Aristotle’s
Metaphysics, Bk. V, lect. 7
(ed. Cathala, Nos. 843844).

35. The Transcendental ''Good"
The good according to its proper intelligibility is a cause, in the
way in which a goal is a cause. This is clear, because the good is that
which all seek after. But that, to which an appetite [tendency] tends,
is the end. Therefore, good, according to its proper intelligibility, is a
cause after the manner of causing of an end.
Commentary on Aristotle’s
Metaphysics, Bk. I, lect. 11
(ed. Cathala, No. 179).

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36. Evil Is a Privation
“Evil,” like “white,” can be said in two ways. For, in one way,
when we say “white,” we can understand “that which is the subject
of whiteness”; in a second way, “white" is “that which is white
inasmuch as it is white,” that is, the accident itself. In like manner,
“evil” can be understood in one way as “that which is the subject of
evil,” and this is something. In another way, we can understand “evil
itself”; this is not anything, but is the privation of something good.
To see this, we must realize that good, properly speaking, is
“something inasmuch as it is appetible”; for, according to the Pliilosopher (Ethics, Book I), those philosophers gave an excellent
definition of good who said, “Good is that which all seek”; evil, how­
ever, is said to be "that which is opposed to good.” Therefore, it is
necessary that evil is that which is opposed to the appetible as such.
That which is opposed to the appetible as such cannot be something,
for three reasons: First, because the appetible is an end, and the order
of ends is like the order of agents. For, if an agent is higher and more
universal, the end for which it acts is a more universal good, for every
agent acts for an end and for a good. . . . Since in efficient causes
there is no infinite regress—for we must arrive at one first agent
which is the universal cause of being—it is necessary’ that there is
some universal good to which all other goods are ordered. The reason
is that, since the appetible moves the appetite, and the first mover
must be unmoved, the first and universal appetible must necessarily
be the first and universal good, which does all things because of its
love of itself. Consequently, as whatever there is in the real order must
derive from the first and universal cause of being, so, whatever there
is in the real order must derive from the first and universal good. But
that which comes from the first and universal good can only be a
particular good, just as what comes from the first and universal cause
of being is some particular being. Therefore, whatever is something in
the real order must necessarily be some particular good. But that
which is good cannot, inasmuch as it is, be opposed to good. Hence,
finally, evil, inasmuch as it is evil, cannot be something in the real
order, but is the privation of some particular good, inhering in some
particular good.
The second reason demonstrates the same truth. Whatever is in
the real order has some inclination and tendency toward that which
is suited to it. But tliat which is appetible is thereby good. Therefore,
whatever is in the real order is proportioned to some good. Evil, how­
ever, as such is not proportioned to good but rather is opposed to it.
Therefore, evil is not something in the real order. But even if evil were
some thing, it would have no tendency, nor be the object of any
tendency; hence, it would have no action or change, because nothing
acts or is moved except on account of the appetite for some good.

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211

The third reason leads to the same truth. Being itself most especially
is that which is desired. That is why we find that ever}’ thing naturally
tends to conserve its being, and avoids what destroys it, and resists
destruction as it is able. Therefore, being itself, inasmuch as it is
appetible, is good. Therefore, it is necessary that evil which is entirely
opposed to good is also opposed to the very act of being. But that
which is opposed to the act of being cannot be something. Hence, I
conclude that that which is evil itself is not something; that to which
evil happens is something, inasmuch as evil deprives its subject only
of some particular good (just as blindness itself is not something, but
that to which blindness happens is something).
De Malo, q. 1, art. 1.

CHAPTER XI

The Predicaments: Substance
and Supposit
82. The predicaments in general
Tlie predicaments, or categories, arc the highest (that is, the
most general) classes of things known. From the point of view of
Aristotelian logic, all predicates are attributes. From the point of
view of grammar, predicates could be classified as substantive or
adjectival. But when we are studying the predicaments, we are
not studying the operation of our mind by which we join one
concept to another, much less the structure of verbal propositions.
Of course, both logic and grammar will be to some extent useful
tools. But we arc going to investigate the various ways of deter­
mining the mode (or way) of being of things in relation to our
knowledge.1 This consideration we shall call “predicamento]
being.” 2
To locate the present discussion, it will be helpful to consider
in summary form the matter to be investigated in this and tlie
following two chapters. The predicaments are intelligibilities
*
de­
rived from being in its first and proper sense (or, “metaphysical
being,” "that-which-is”). Substance is derived by total abstrac­
tion, accidents by total and formal abstraction. With the excep­
tion of quantity and quality, the predicamcntal accidents also in­
volve formalization. Each of these predicamental intelligibilities
1 See also, Selected Passages, No. 38; this is an extremely important group
of texts.
3 See Selected Passages, No. 37.
3 It may be advantageous to review sec. 74 on intelligibilities or to re-read
Selected Passages, No. 33.
212

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PREDICAMENTS; SUBSTANCE; SUPPOSIT

213

is considered as an entity, that is, as analogous to an individual
real being. Thus, we can speak predicamentaUy of substance and
its esse and accidents and their esses, although in the real order
there is but one esse of the substance together with its accidents.
Hence, in relation to extramental beings, the predicaments are
secondary analogates by the analogy of proportion. Among the
predicaments—because in the real order accidents have esse only
through substance, and predicamental accidents are by their na­
ture modifications of substance—these accidents are secondary
analogates of predicamental being; substance is the primary
analogate of predicamental being.
To facilitate our understanding of the predicaments (predica­
mental being) and to establish their place in metaphysics, it is
necessary to recall briefly some of the discoveries we have already
made about being. Being, in its first and proper sense, is tliat
which is, or any thing having an act of existing (esse). As evi­
denced by the existents of our experience, being in this primary
sense comprises two principles: the “that-which (-is),” or “thing­
principle” and the principle by which the thing exists, the “esseprinciplc.” This pair of principles—though not the first to be dis­
covered—is the most basic potency-act correlationship of being.
In this correlationship, the thing-principle is, of course, potential,
and the esse-principle is its correlated act. Primarily, then, the
thing-principle is a whole principle which exists by its proper
esse. It is an entire individual of a definite kind with all its com­
ponents and modifications and all its capacities.
As the existents of our experience show, the tiling-principle is
itself a composite of various other principles, namely, matter and
substantial form and substance and accidents. These, as we have
seen, constitute other potency-act correlations within a being.
They arc rightly called principles of being, precisely because they
are components of the entire thing-principle whose proper act is
esse. For this reason, too, they are rightly called beings according
to an analogy of proportion. But, let us note, they are so called
only by reference to being in its first and proper sense; that is to

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[82]

say, because they, as intrinsic principles, in some way contribute
to the structure o£ being (in that sense).
Thus, we see that being, metaphysically taken, has many mean­
ings. By analogy o£ proportion the whole thing-principle and its
intrinsic components are called beings. This whole thing-principle
presents its complex make-up to us as follows: (1) The experi­
enced thing presents itself as directly ordered to esse; and accord­
ing to this presentation, it is called substance. As designating this
presentation "substance” means “that to which esse belongs in it­
self.” (2) The same thing-principle also presents itself as a prin­
ciple of a certain kind, or essence (nature). Our understanding
of this presentation involves both natural (total) abstraction and
judgment (for example, “This is a man”).4 (3) The same thing­
principle presents itself as basically composed of primary matter
and substantial form. What this presentation involves has already
been analyzed.5 (4) The same thing-principle presents itself to
us as intrinsically modified in various ways. These modifications
are called accidents, and the thing-principle, inasmuch as it is a
potency for these accidents, is called their substantial subject or,
simply, their substance. A substance according to this presenta­
tion means “a subject of accidents.” All these presentations of
being are metaphysical as has been indicated.
Bearing these distinctions in mind, wc arc now in a position to
consider the nature of predicamcntal being and its relation to
metaphysical being, which we have just summarily considered.
First of all, we should note that it is being in the sense of thing­
principle (and so being by an analog}' of proportion) which fur­
nishes the foundation of predicamental being. It is precisely the
thing-principle as a principle of being in its first and proper
sense that gives rise to the predicaments. This is the basic fact
1 Men do not commonly perform acts of simple apprehension. Usually
simple apprehensions are (virtual) parts or functions of judgments. Only a
relatively sophisticated person makes simple apprehensions. On this point,
see C. P. Klubertauz, The Philosophy of Human Nature (New York,
Appleton-Century-Crofts, Inc., 1953), pp. 173-177.
8 See above, secs. 32 and 33.

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215

which gives the predicaments their rightful place in metaphysics.
From the thing-principle, as we have observed, we can by
means of total abstraction obtain an intelligibility which we call
an “absolute nature” (for example, man, horse, tree).6 This abso­
lute nature can be predicated of various individual existents. It
expresses their substantial nature. Substance as obtained in this
way and used as a predicate is called "prcdicamental substance”
or “second substance.” Prcdicamental substance, thus, is nothing
else than any absolute substantial nature predicable of real indi­
vidual existents.
Again, the tiling-principle presents itself as modified in various
ways. Some of these modifications pertain to it precisely as this
individual, while others pertain to it by reason of its nature, or
the kind of thing it is. These modifications are called accidents.
By means of formal abstraction, we can consider these modifica­
tions (accidents) in themselves apart from any substance. In­
deed, we can consider them as if they were substances (per
modum substantiae); and it is precisely as considered in this way
that they are placed in the predicaments. We will take up the
consideration of accidents in some detail in the two following
chapters.
One further general consideration is necessary. Because predicamental being is so called by an intrinsic analogy of propor­
tion to metaphysical being, it is traditional to ask about the prin­
ciples of predicamental being. As we have seen, the analysis of
metaphysical being can be partially represented in a diagram like
the following:
I' substance
essence7 ¿
,
I accident
esse

{

By an analogy of proportion—this time an extrinsic analogy, in­
asmuch as our mind considers predicamental being according to
"See above, secs. 11, 18, and 33.
’This is not the strict sense of essence but a wide one; sco above, sec.
34.

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CHAPTER XI

the model provided by extramental being—prcdicamcntal being
is considered as composed in the following way:

i essence
substance -j
I esse
(predicamental) being -

accident

r essence

I esse

The similarity-in-difference between these two analyses has
caused much confusion, and it will be necessary that we take
great care in the discussion of both substance and accident. We
will take up the point of the "esse" of predicamental being in
detail in the next chapter. For the moment, however, let us care­
fully note that the understanding of substance as composed of
essence and esse does turn out to be quite similar to the nature
of metaphysical substance which has been made in this section.
However, there are differences. Esse, as considered to be a prin­
ciple of predicamental substance, is called “substantial esse," or
“esse without qualification." Taken this way, substantial esse is an
intelligibility, not an immediate principle of metaphysical being.
Why is the analysis of the principles of being (as we made it,
for example, in Chapter V) not sufficient? This analysis is suffi­
cient to understand real things in the real order, but not sufficient
to enable us to deal with them intellectually. In examining the
structure of real things in the real order, we have found that the
essence (the thing-principle, that-which-is), is composed of two
principles, a principle by which the being is something having
esse in itself (substance), and other principles (accidents) by
which that something is variously modified. When we consider
substance and accident as principles by which something has esse
in itself and by which something is modified, we are trying to
understand them according to the manner in which things exist.
Such an understanding is difficult and roundabout—a fact which
is manifested by the awkward circumlocutions necessary to ex­
press it. On the other hand, it is very easy to understand and deal

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PREDICAMENTS; SUBSTANCE; SUPPOSIT

217

with these principles when they are conceived as things; in other
words, it is easy to deal with the principles of tilings by means
of intelligibilities. When we classify these intelligibilities accord­
ing to what they represent, we have the predicaments. The pre­
dicaments, therefore, are conceived in the manner proper to the
human understanding. Since what the predicaments intelligibly
contain directly relates to the real order, they are “first intention”
predicates.8 But we must be careful not to confuse the manner in
which they are conceived with the ontological mode of being
which they ultimately signify.
A “thing” can share in being in ten basically different ways,’
inasmuch as
it has being simply or substantially ................................ Substance
it has being in a qualified manner or accidentally..........................
on account of something intrinsic to the thing
which is absolute
and follows upon matter....................................... Quantity
or follows upon form................................................ Quality
or relative, that is, ordering one to another................. Relation
or on account of something extrinsic to the thing
partially
of which the tiling is principle................................ Action
or of which it is the term
(that is, term of another’s activity) ....................... Passion
wholly extrinsic
as measure of the thing
4 A “first intention" is a knowledge (concept, judgment, reasoning) about
some object, cither a real thing or something conceived after the manner of
a real thing, and referring to the kind of existence proper to such an object.
It is contrasted with “second intentions." A second intention is a knowledge
about some object according as it is understood and referring to the kind
of being that an object has in a mind, that is, to its intelligible nature as
understood. A second intention is called “second,” because we must first
know an object before we can think about our knowledge of that object.
Among the second intentions there are the “predicables” spoken of in
logic. The predicables are classes of predicates according to the intelligible
relations they have to subjects. The predicables are genus, difference,
species, property, accident. Because they are second intentions, the pre­
dicables are beings of reason.
“For a fuller presentation of the derivation of the predicaments, see
Selected Passages, No. 39.

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[82-83]

according to time .....................................................When
according to place
simply ................................................................. Where
considering also the order of
the parts among themselves.................................. Situs
as joined to a thing according to
some human purpose................................................ Habitus

To understand the predicaments in particular, it may help to
look at some sample sentences employing the predicaments. The
order of these examples will follow the order of the predicaments
as given above. (1) “John Smith is a man”; "John Smith is ra­
tional.” (2) “My dog, Rover, is large.” (3) “The house is white
and square.” (4) “John Doe is the son of Richard Doe.” (5)
“John Doe is building a house.” (6) “This house is being built
by John Doe.” (7) “That manuscript is ancient.” (8) “Yesterdays
storm was local” (9) “The broken step is the bottom one.” (10)
“That man is warmly clothed’; “Tlie work horses are shod.”
All the accidental predicaments are denominations,10 that is to
say, they are understood as expressing the subject (that which is)
under some formal determination. They do not express a part or
principle of the subject, for, if they did, they could not be predi­
cated of the subject directly. But, though all the predicaments are
understood after tlie manner of forms, in tlie thing itself they do
not all have the same mode of being. Substance, as the principle
by which the thing has subsistence, is a composite of matter and
form. Quantity and quality, as principles by which a thing is
quantified and qualified, are forms or at least quasi forms, which
are inherent perfections of the thing itself. But the other predica­
ments, though also understood as forms, are not forms in them­
selves, though some of them are acts of, and inherent in, the sub­
ject, while others are more or less extrinsic to tlie tiling which is.
83. Substance
Real being manifests itself to us in our experience as something
which exists in itself and is variously modified, for example, “this
10 On this point, see Selected Passages, No. 40.

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PREDICAMENTS; SUBSTANCE; SUPPOSIT

219

brown horse.” That principle o£ being, which wc find in real
being, by which that real being (exists) in itself and not in an­
other and which therefore can properly be said to be, is sub­
stance. In all our experience of real beings, even if we understand
no more about them than can be expressed in the words, “This
is,” we have already implicitly reached substance. For that which
we designate by the word “this” exists in itself. We may be ig­
norant of, or mistaken about, what the substance is, but at least
we know it as substance, implicitly. If someone were to imagine
that he could directly experience an accident without experi­
encing substance, he would involve himself in a contradiction.
For an accident is that principle of being to whose nature it
belongs to be in another. Hence, to say, “We can experience that
which is in another without experiencing the other in which it
is,” is a contradiction.’1
Note that the word substance and its primitive meaning refer
directly to “a permanent subject of accidental changes.” But by
reflection and analysis we see that this is a superficial description;
we see that the ultimate subject of accidental change has to have
an act of existing in itself, whereas not everything which is in
itself necessarily has to be a subject of change. Hence, wc define
substance as that to whose nature it belongs to be in itself ( not in
another subject).
If we ask about the divisions or kinds of substance, substance
can be divided in various ways. The substances we know are
composite substances, made up of principles related to each other
as act and potency (that is, matter and form); the contrary of
composite substance would be simple substance, one not divisible
into substantial principles or parts. The substances which are
found in our immediate experience are material substances; tlie
contrary of this would be spiritual substance which contains no
11 If, by a miracle, in a particular case sensible qualities exist in quantity
which has an act of existing after the manner of a substance, our experience
is not thereby faulty, though we may make the mistake of judging that in
this case quantity itself is in a subject (as in tlie nature of accidents). See
below, sec. 90.

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chapter xi

[83-84]

matter. It would therefore be a simple, or incomposite, substance
(for example, an angel).12
Sometimes writers on philosophy speak of complete and incom­
plete substance; by complete substance they mean substance as
we have been speaking of it; by incomplete substance they mean
the substantial principles, matter and form. Finally, there is the
distinction into “first” and “second” substance. “First” substance
is the singular substance which exists as such in the real order
(John Doe, Citation). First substance is never a predicate; it is
not in a subject but is the subject itself. “Second” substance is the
substance which is a predicate (man, horse); it does not exist as
such in tiie real order, for it is an absolute nature which is
abstracted from individuality. It is called "second” substance, be­
cause it presupposes the existence of first substances in the real
order of which it can be predicated.13
84. Supposit and person
First substance is not a predicament at all, because it is never
a predicate. (Grammatically, the subject of a sentence may be
placed after a verb, but we are not dealing with grammar here;
we arc dealing with the thing which is known.) The first sub­
stance is the singular substance which exists. When we want to
designate the being precisely as an existing, substantial, complete
individual, we call it a “supposit.” To stress the fact that the sup­
posit is a complete individual, not something common to many
(like second substance) or just a part (not an integral part, like
a hand, or an essential part, like the body of a living thing), we
say that the property of a supposit is “incommunicability.”

N.B. Distinguish the supposit as spoken of in metaphysics (the in­
communicable first substance) from the supposit spoken of in logic
“ Note however, that spiritual substance is not in the predicament of sub­
stance. When we say, “An angel is a substance,” die term and conception
substance is used analogously not univocally. See Selected Passages, Nos. 24
and 28.
“ See Selected Passages, No. 41.

[83-84]

PBEDICAMENTS; SUBSTANCE; SUPPOSIT

221

(the ultimate subject of predication). The supposit of logic is a
second intention; it is considered as receiving predicates. The supposit
in logic may be a thing (Peter, a tree); it may be a collection (three
men, a flock); it may be an abstraction (humanity) or a being of
reason (nothing).

The traditional definition of a supposit is “a distinct subsistent
individual in a particular nature.” The terms “distinct” and “indi­
vidual” are used to exclude the communication of a nature to an
individual or another supposit. The term “subsistent” is used to
mean “something which exists with its own proper and propor­
tionate act of existing.” What then is the difference between an
individual thing and a supposit? Ordinarily and naturally, an in­
dividual being has its own proper act of existing, even though
there is a real distinction between the nature or essence and the
act of existing. But the term “individual thing” only connotes an
act of existing, while the term “supposit” explicitly means “having
its own proper act of existing.” A technical term sometimes used
for “supposit” is the word “hypostasis.”
The supposit in a rational nature has a special term, namely,
“person.” A person, therefore, from the point of view of meta­
physics, is a “rational supposit," that is, “a distinct subsistent indi­
vidual in a rational nature." Personality, therefore, namely, that
(quasi form) by which a person is precisely a person, is the
proper act of existing proportioned to a rational nature. In other
words, a human being is a person by having his own act of ex­
isting.
N.B. Distinguish this metaphysical meaning of person and person­
ality from the everyday and psychological meanings of those terms.
The everyday meanings can easily be found in a dictionary. The
meaning of “personality” in the science of psychology can be expressed
thus: “the sum total of knowledge, attitudes, habits, ways of acting,
and so forth, formed into a single pattern.” 14
14 Cf. Francis L. Hannon, Principles of Psychology (Milwaukee, Bruce,
1951), pp. 595-597.

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[85-87]

85. Digression on the backgrounds of the
problem of personality
Why distinguish between a person and an individual rational
nature, since as was said above the individual nature of a being
ordinarily and naturally has its own proper act of existing? His­
torically, the problem arises from a theological consideration.
According to Christian theology, Jesus Christ is a Divine Person
(namely, the Second Person of the Blessed Trinity), who became
man without ceasing to be God; in other words, he assumed a
human nature. Obviously, Christ did not assume universal human
nature but a singular human nature, as singular and sensible as
that of any man. But it cannot be said that Christ was a human
person, for then he would be two persons, one of which was God,
the other an ordinary man. Hence, there is one case of a singular,
individual human nature, with an act of existing, which is not
a human person. In trying to work this problem out, theo­
logians have made many efforts in different directions: for
example, that personality is a double negation of being actually
assumed and being able to be assumed; a single negation, of
being assumed; a “mode” which is some kind of form really dis­
tinct from the nature. The simplest, most straightforward expla­
nation is the one given above.

86. Definitions

Predicamental being is the thing-principle of extramental
( metaphysical ) being considered as a whole in relation to our
knowledge. It is divided into the ten predicaments. (The thing­
principle is “that-which [-is]”; it is “being” by an analogy of pro­
portion to metaphysical being.)
Metaphysical being is being in its first and proper sense: “thatwhich-is.”
A predicament (category) is one of the highest classes or

[85-87] PREDICAMENTS; SUBSTANCE; SUPPOSIT

223

genera of things known. For example, substance, quantity, qual­
ity.
A predicable is a predicate considered precisely as predicated,
according to its relationship to the subject. It is a second inten­
tion. For example, “man as a species.”
A substance is that by which a being has esse in itself. (This is
a definition of substance as a principle of metaphysical being.)
A substance is that which properly and in the first place is said
to be. (This is a definition of predicamental substance.) For ex­
ample, “John is a man.”
An accident is that by which a being exists in some modified
way. (This is a definition of accident as a principle of metaphysi­
cal being. )
An accident is that whose being is inherence (in a subject).
(This is a definition of predicamental accident.)
First substance is the singular existing substance.
Second substance is the absolute nature which is predicated as
substance.
A supposit is a distinct, subsistent individual in a particular
nature, whose property it is to be incommunicable.
A person is a rational supposit.
Personality, that by which a human individual is a person, is
the proper act of existing proportioned to a human nature.
Hypostasis is another name for supposit or person.
87. Readings

St. Thomas Aquinas, Summa Theologiae, Pt. I, q. 3, art. 6 (sub­
stance and accident in creatures and in God), q. 29, arts. 1 and 2 (the
meaning of "person”), q. 50, art. 1 (the nature of a pure form); q. 30,
art. 4 (how the term “person” is said of the Persons in God); Pt. Ill,
q. 2, art. 2 (the Hypostatic Union), q. J7, art. 2 (Christ as one being
according to esse); On Being and Essence, chap. 2, par. 1-3 (meaning
of “essence" in sensible things); On the Power of God, q. 2, art. 2, ad
2 (relation of one predicament to another), q. 7, art. 3 (on substance
and genus).
Etienne Gilson, Spirit of Mediaeval Philosophy, trans. A. H. C.
Downes (New York, Scribner’s, 1936), pp. 191-206.

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Selected Passages from St. Thomas Aquinas

37. The Meaning of "Predicamental Being’
The term “being,” inasmuch as it signifies the thing to which esse
belongs, thus signifies essence, and is divided into the ten kinds. But
it is not divided univocally, since esse does not belong to all these
kinds in the same way, but it belongs to substance per sc, to the other,
in other ways.
Quodlibet II, art. 3.
“Being” which is divided by the ten predicaments signifies the
natures of the ten kinds according as they are in act or in potency.
Commentary on Aristotle’s
Metaphysics, Bk. X, lect. 3
(ed. Cathala, No. 1982).
38. Predicamental Being Compared with Being-known
Being is used in two ways [St. Thomas does not say only two].
... In one way it signifies the essence of a thing, and is divided into
the ten predicaments. ... In another way, it signifies the truth of a
composition.
Contra Gentiles, Bk. Ill,
chap. 9.

Being is used in two ways. In one way it signifies the nature of the
ten predicaments, and in this sense neither evil nor any other priva
*
tion is “being” or “something.” In another way [it signifies] the answer
to the question, “Is it?” and in this sense evil is, as also blindness is.
De Malo, q. 1, art. 1, ad 19.
Being is used in two ways. In one way, it signifies the entity [entitos]
of a thing, as it is divided into the ten predicaments, and in this sense
it is coextensive with “thing.” In this sense, no privation is a being,
and consequently neither is evil. In another way, being signifies the
truth of a proposition which consists in a composition, whose charac­
teristic note is the verb is, and this is the being with which we answer
the question, “Is it?” Thus, we say that blindness is in the eye . . .
Summa Theologiae, Pt. I,
q. 48, art. 2, ad 2.

39. The Derivation of the Ten Predicaments
Being is divided into the ten predicaments, not univocally, as a
genus is divided into species, but according to a different way of

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PREDICAMENTS; SUBSTANCE; SUPPOSEE

225

being. But the ways of being are proportional to the ways of predicat­
ing. For when we predicate one thing of something else, we say, “This
is that,” and so the ten kinds of being arc called ten predicaments.
Predication is done in three ways. The first way is, when something
pertaining to the essence of a thing is predicated of a subject, as when
I say, “Socrates is a man,” or, “Man is an animal,” and in this way
there is the predicament of substance. The second way is that by
which something, which is not of something’s essence, but inheres in
it, is predicated of that thing. That which inheres either pertains to the
matter of the subject, and thus there is the predicament of quantity,
for quantity properly follows upon matter. . . . Or, that which inheres
follows die form, and thus there is the predicament of quality. There­
fore, the qualities are founded upon quantity, as color on surface, and
figure on lines or surfaces. Or, that which inheres is with regard to
another, and thus there is the predicament of relation. For when I
say, “Man is a father,” nothing absolute is predicated of man but a
regard [respect], which is in man to something outside him. The
third way of predicating is, when something extrinsic to that thing is
predicated of it after the manner of a denomination. For it is as
denominations that the intrinsic accidents are predicated of substance;
we do not say, “Man is whiteness,” but, “Man is white.”
But to be denominated from something extrinsic is found to some
extent commonly in all things, and to some extent especially in those
which pertain only to man. Now, something is commonly denominated
from something extrinsic, either according to the intelligibility of
cause, or according to that of measure (for something is denominated
“caused” and “measured” from something extrinsic). Since there are
four kinds of causes, two of them, that is, matter and form, are parts
of the essence. Consequently, the predication which takes place
according to these two principles, pertains to the predicament of
substance; for example, if we say, “Man is rational,” and “Man is
corporeal.” But the final cause does not cause anything separately
from the agent. For the end is a cause, inasmuch as it moves the agent.
Therefore, there remains only the efficient cause from which some­
thing can be denominated as from something extrinsic. Thus, there­
fore, inasmuch as something is denominated from the agent, there is
the predicament of passion, for “to undergo" [paît] is nothing other
than to receive something from an agent. But, conversely, according
as something is denominated an agent from an effect, there is the
predicament of action. For action is the act from the agent in some­
thing else, as was said above.
A measure may be extrinsic or intrinsic. An intrinsic [measure], for
example, is the proper length of something, or its width, or depth;
from these, therefore, something is denominated as from an intrinsic

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inherent, and so they pertain to the predicament of quantity. But the
extrinsic measures arc time and place. Inasmuch as something is
denominated from time, there is the predicament “when”; and
inasmuch as something is denominated from place, there are the
predicaments “where" and “situs” (which adds to “where" the order
of parts in place). (But such a distinction was not necessary with
regard to time, since the order of parts in time is involved in the very'
intelligibility of time, for time is the numbering of motion according
to the prior and the posterior.) Thus, therefore, something is said to
be when or where by denomination from time or place.
Finally, there is a special denomination with reference to men. For
in other animals, nature has sufficiently supplied the things which
pertain to the preservation of life, such as horns for defence, a thick
and hairy' hide for covering, claws for cutting without being hurt, and
so on. And so, when such animals are said to be armed or clothed or
shod, in a way they are not denominated from something extrinsic,
but from some of their parts. Consequently, these predicates are re­
ferred in them to the predicament of substance, as if we were to say'
that “Man is handed," or “footed.” But such parts could not be given
to man by nature, both because they' are not suited to the delicacy of
his bodily constitution, and because of the many kinds of activities
which are suitable to man inasmuch as he possesses reason, to which
determined instruments could not be adapted by nature. But in place
of all such instruments, man has reason, by' which he prepared
exterior things for himself, in place of the parts which animals have
intrinsically. Hence, when man is said to be armed, or clothed, or
shod, he is denominated from something extrinsic, which does not
have the intelligibility of a cause nor of a measure. Hence, this is a
special predicament, and is called “habitus.” But it is to be noted, that
this predicament is attributed to other animals, not as they' are con­
sidered in their nature, but as they' come into human use, as if we
say that “A horse is trapped, or saddled, or armed.”
Commentary on Aristotle's
Physics, Bk. Ill, lect. 5.

40. The Predicaments as Denominations
[Aristotle] says that there must be something of which all forms
are predicated, on the condition that we understand this subject . . .
to be a different quiddity' and essence.
We must note that what has just been said is not to be understood
of univocal predication according to which genera are predicated of
the species which arc defined by' the genera. For “animal" and “man”
[as predicated of each other] are not essentially distinct. But we must

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227

understand this of denominative predication, as when “white” is predi­
cated of “man.” For “white” and “man” arc essentially distinct.
. . . denominative predication, in the way in which accidents arc
predicated of substance. For this proposition, “Man is white,” is
true, but not, “Man is whiteness,” nor “Humanity is whiteness.” In
the same way. the proposition, “This material thing is a man," is true,
but not, “Matter is man,” nor, “Matter is humanity.” The very fact
of concrete or denominative predication shows, that, as substance is
essentially distinct from accidents, so matter is essentially distinct from
substantial forms.
Commentary on the Seventh
Book of the Metaphysics, lect.
2 (ed. Cathala, Nos. 12871289).
41. The Meaning of “Substance”
And first he posits that there are said to be substances existing in
the real order, some of which are admitted by all, namely, the sensi­
ble substances, such as the earth and the water and other elements,
and likewise, according to the order of nobility and perfection, plants
and animals and their parts, and finally the heavens, and their
parts. . . .
He posits the ways of taking “substance" according to the accept­
ance of reason. . . . one of which is that “substance” is called the
quiddity of some natural substance and this is nothing other than the
whatness of a natural thing.
Commentary on Aristotle’s
Metaphysics, Bk. VIII, lect.
I (ed. Cathala, Nos. 16831684).
“Substance” is used in two senses. In one way, it means the supposit in the genus of substance, which is called “first substance” and
“hypostasis,” to which it properly belongs to subsist. In the other
way, substance means “what a thing is,” which is also called the nature
of the thing. . . . Therefore it is said in the Predicaments, that sec­
ond substances, which are genera and species, do not mean “this
something,” which is a subsisting substance, but they mean “what
sort of a thing,” that is, a nature in the genus of substance.
Thus, therefore, the Philosopher proved above, that “one” and
“being” do not signify a substance which is this something, but we
must seek for something which is one and being. In the same way, we
seek something which is man or animal, like Socrates or Plato. Finally,
he showed that these terms signify the natures of the tilings of which

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they are predicated, and not something else added like accidents. For
in this, the common terms differ from accidents, though it is common
to both common terms and accidents not to be tins something, because
common terms signify the very nature of supposits; but accidents do
not, but rather they signify some added nature.
Commentary on Aristotle’s
Metaphysics, Bk. X, lect. 3
(ed. Cathala, Nos. 19791980).

CHAPTER XII

Accidents in General: Quantity

and Quality
88. The nature of accidents
The investigation of predicamental accident is a further de­
velopment of our study of predicamental being. To help us to
locate this study properly we will summarily reconsider what we
already know about accidents.
The thing-principle of (metaphysical) being designates the
whole individual which possesses the act of existing. This thing­
principle manifests itself as a substance inasmuch as an existent is
a whole directly ordered to esse, is of a certain kind, can be sub­
ject to changes and modifications. Again, the thing-principle man­
ifests itself as modified in various ways, some of which come and
go, others of which are permanent; some of which pertain to the
individual as such, others of which belong to the individual be­
cause of the kind of thing it is. These modifications are called
“accidents.” An accident, then, is that which is in another as in a
real subject, by which that subject is (not simply, but) in a modi­
fied way; the proper character of accident is that of a real prin­
ciple by which the thing-principle of finite being is constituted;
tins principle is really distinct from its coprinciple, substance.1
Secondly, accident is a direct principle of predicamental being.
As we have seen briefly,2 the analysis of predicamental being
gives us the division into predicamental substance and predica­
mental accident. Predicamental substance is the absolutely con1 See above, secs. 30 and 31.
* See above, sec. 82.
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sidered nature according to which a real individual thing exists in
itself. Predicamental accident is a denomination predicable of
real individual existents because of the modifications which these
existents manifest to us. As a denomination, the predicamental
accident is taken concretely; for example, “white,” “tall.” The con­
crete accidents implicitly include their subjects; for example,
“white” implicitly includes (some) subject. But by formal ab­
straction, we can consider the accident without its subject; for
example, “whiteness,” “tallness.” In this abstraction, we use a
manner of understanding and speaking about the abstracted acci­
dent as if it were a substance and a real thing ( per modum sub­
stantiae).3
Hence, accidents can be thought about predicamentally and
spoken of in two ways. ( 1 ) Taken concretely, as direct predicates
(for example, “white”), all the accidents are predicated as forms
inhering in a subject. Taken in this way, they implicitly include
the subject. (2) Taken abstractly (for example, “whiteness”),
the accidents no longer include the subject. Because the concrete
accident explicitly includes the accident and implicitly includes
the substance, it is a compound (a per accidens unit)4 that can­
not be placed in any predicament. Only the abstract accident
can be placed in a predicament (for example, of quantity, of
quality). As abstract, the accidents are not predicated directly of
any subject but only indirectly (in obliquo). For example, we
predicate a concrete accident directly when we say, “John is
short”; but to predicate the abstract accident of John, we must
add a word which relates the accident to him, as, "John has short­
ness.” But note that when we think of an abstract accident in
itself or use it as an indirect predicate, we deal with it as if it
were a substance or thing.
The predicamental accidents are understood as forms and dealt
with after the manner of substances. Consequently, we also refer
an essence and an act of existing to them, and we designate this
3 On this point, see Selected Passages, No. 44.
* See above, sec. 75.

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231

act of existing as an “accidental esse.” As we saw above, being in
its first and proper sense is constituted by the two principles of
esse and essence, and the latter in turn is constituted by sub­
stance and accident. Wc also saw that predicamental being is
analogously divided first into substance and accident and that
these principles, in turn, are divided into substantial essence
(essence in the strictest sense) and substantial esse, and acciden­
tal essence and accidental esse.5
Predicamental being is divided into substance and accident. Of
these two principles, substance is being by itself, or by essence.
Hence, when we are strictly speaking of predicamental substance
as a principle of predicamental being, its substantial esse is our
way of considering it as real. Thus, “man” is a predicamental
substance; if we want to assert it as real, we say, for example,
“Man is a substance or a nature.” (This is per se predication.)
Therefore, we can consider substantial essence and substantial
esse as merely different considerations, for substance is predica­
mental being by itself.
But predicamental accident is not being by itself. By itself, or
by its essence, the predicamental accident is abstract, and, as
abstract, it cannot truly be signified to be—it is not true that
“Whiteness is” all by itself. We can say, "Whiteness is,” only
inasmuch as it is related to, and dependent upon, substance; that
is, it is true that “Whiteness is” only in the sense that “Some
tilings are white by whiteness.” Hence, predicamental accident
is said to be, not simply but secondarily, in dependence upon
substance. Of itself, it is not predicamental being, but it shares in
the esse which is attributed to substance. From this point of
view, accident is (predicamental) being analogously with sub­
stance by the analogy of participation.6 Therefore, it is also true
•See the diagram above, sec. 82; see also, Selected Passages, No. 43.
•The analogy of participation in predicamental being is somewhat
different from the analogy of participation in being in its proper sense.
When we say, “God is being by essence, creature is being by participation,’
we mean that God’s being and the creatures’ being are really distinct.
When we say, “Substance is predicamental being by essence, accident is

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that the accidental esse is a completely different intelligibility
from that of the accidental essence. The essence of an accident
is the particular kind of modification it is;7 its esse is an “inesse”
or an inherence in a subject? Thus, when we want to give the
formal definition of a real accident, we begin by saying, “That
which . .
even though in the real order an accident is not a
being or even a thing. Only the modified being properly exists,
and the modification is a principle by which something is in
some way or other. Further, the is which is attributed to the
abstracted accident in its definition is not an existential act in
the proper sense, for, if it were, the abstract accident would be
a being in the real order.® When we understand an abstracted
accident after the manner of a substance (for example, “white­
ness”), and wish to signify that accident as real, we attribute
the act of existing to it. What does this attribution rest on? It
rests on the fact that for an accident to be real in the way
corresponding to its nature, it must be united to an existing thing
as act to the potency which is substance, and by that union the
predicamental being by participation,” we do not attribute the same kind of
distinct being to the accident as the substance has. Nevertheless, the manner
of predication is the same.
Because many Thomists have not distinguished between being in its
proper sense and predicamental being, they have said that substance and
accident are analogous according to the analogy of proper proportionality
(substance is to its esse as accident is to its own esse). It is true that
there are several reasons for making this mistake. First, as we shall sec, there
is no other way in which we can signify an accident as real except by
attributing to it an esse—we say, “It is”; but what is the meaning of “is”
in this usage? Secondly, there is a perfectly correct way in which we can
speak of an “accidental esse,” as we shall also see; but the fact that we
consider accidental esse as other and distinct from substantial esse is not
by itself a proof that there arc two varieties of existential act. Only a latent
Platonism will attribute to the real order all the structures and distinctions
found in the inind.
In the proper way of understanding accident, the abstract accident (for
example, “whiteness”) has no existential act at all; the concrete accident
(for example, "white") includes in its meaning the subject of existential
act and so “has” an existential act, not of itself but by reason of the sub­
ject which is included.
' On the meaning of essence in accidents, see Selected Passages, No. 43.
'See also, Selected Passages, No. 45.
* Cf. Selected Passages. No. 42.

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ACCIDENTS; QUANTITY; QUALITY

233

accident “has” an act of existing, namely, the act of existing of
the being whose modification it is.
Because an accident does not have its own proper distinct act
of existing, it is not a being in the proper and first sense of that
word. St. Thomas sometimes says that an accident is not a being
but pertains to being (magis entis quam ens—it is rather of a
being than a being) and that it can be called “the being of a
being” (ens entis).
Note that accident is first of all an “addition” to substance in
the order of essence. We can, as we have seen, talk of an “acci­
dental esse” to indicate that a particular accident is modifying
some thing which actually is. We can even say that the “acci­
dental esse” adds to the substantial esse of a thing. To be learned
is to have more being than to be without learning, though learn­
ing is “only” an accident. What we should understand by such
expressions is not that another really distinct act of existing has
been added to the act of existing of the substance but that the
act of existing of the man (taken concretely in the real order) has
now been extended, enlarged to be the act not only of the sub­
stance but also of the modification “learning.” This is merely a
particular application of the theorem, “Act and potency are pro­
portioned to each other.” If that-which-is ( substance 4-acci­
dents) is really more than it was before, then the act of existing
is really more than it was, not in reference to itself but in refer­
ence to the increase of the potency whose act it is.
If we keep this in mind, we will not be tempted to think of
accident and substance in terms of a pin and pincushion or of
clothes and the man. An accident is really distinct from the sub­
stance, but it combines with the substance to form a composite
subject (that-which-is) for the unique act of existing. Hence, an
accidental modification of a being may be a profound modifica­
tion of the very act of existing of that being (for example,
moral goodness is “only” an accident).
As we shall see when we begin to consider the various acci­
dents in particular, “accident” is an analogous term. The in-

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telligibilíty (ratio)10 of accident is that of a form, and even of a
substantialized form. But this intelligibility “after the manner of
a form" is not a mirror image of reality. The different accidents
each realize tins intelligibility differently. We shall see this more
clearly as we go on, but it is necessary to be forewarned, lest a
univocal notion of accident creep in.

89. Quantity and quality

To consider quantity in itself, what it is, what are its properties,
and so on, belongs to the philosophy of nature. We are interested
in quantity only to the extent that it is a principle of being. By
quantity we mean here "continuous quantity” or extension. There
is another kind of quantity, namely, discrete quantity. ( Discrete
quantity is number, whose consideration belongs entirely to the
philosophy of nature.) Continuous quantity or extension is de­
fined as "that which has parts outside of parts” (tin’s is a defini­
tion of the abstract accident, quantity).
The first question that arises is that of the distinction between
matter and quantity. There seem to be no unequivocal instances
of a change in quantity while the matter remains constant; hence
we are not able to use the argument for a real distinction based
on a real change. Moreover, matter does not exist without quan­
tity, and quantity is not naturally found as an existing being
without matter. It seems that the only way to approach this
question on a philosophical basis is that of a deduction from the
principles of act and potency. If we go back to the original evi­
dence from which we found that there is a distinct substantial
principle called primary matter, we recall that primary' matter
is tlie common, determinable element or principle in substantial
change. It is, therefore, pure potency' in the order of essence.
Now, what is the nature of quantity? It is in potency to divi­
sion, but of itself it is actually “spread out,” such that in relation
to place one part is here and another there. Therefore, quantity
is an act. Hence it cannot be realty identical with matter but
10 On the meaning of “intelligibility,” see above, sec. 74.

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ACCIDENTS; QUANTITY; QUALITY

235

must be really distinct from matter. On the other hand, by its
nature as extension, it presupposes some substance, for the parts
which are outside of other parts must be parts of something; they
cannot just be parts (although they can be abstractly under­
stood in that way). Therefore, quantity is an accident. Quantity
is in a subject, or “inheres in” a subject, and can be correctly
described as an intrinsic modification of a substance. Moreover,
quantity is to be found in all the tilings of our experience, and
all these things are material; hence quantity has an intimate
connection with matter.
In relation to other accidents of material things, quantity is
the basic accident. It is obvious that quantity is presupposed for
the accidents of time and place, situs and habitus. It is also
presupposed for qualities like color (which is a modification of
a surface), figure, hardness, softness, and the like, and for the
actions and passions of material things, as we can see from a
rapid glance at some of them (for example, chemical activities).
The qualities of material things are generally considered to
belong to four classes: shape and figure (which are “qualities of
quantity”), power (and the lack of it), habit and disposition, and
passions (that is, the affections of tilings which are changed,
such as hot or cold, as well as such modifications which arc
similar to dispositions but are completely temporary, as blush­
ing). These various accidents are similar in that they all desig­
nate some way in which a real thing is over and above its sub­
stantial determination. All of them presuppose a subject; that is,
there must be something which is shaped, has power, has
acquired a habit, and so forth. Any of them can be appropriately
pointed out in answer to the question, “What sort of thing is it?”
(hence tlie name quality, derived from the Latin interrogative
pronoun or adjective qualis which means “what sort of?”).
Thirdly, all of these various accidents are similar in that (a)
they modify a substance absolutely or in itself, that is, not in
relation to some other things, and (b) they can be directly con­
ceptualized and defined. Hence, qualities are “formal accidents,”

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that is, the analogy between form and matter on the one side and
quality and substance on the other is very close from the point of
view of the ways in which they are understood, and, as wc have
seen, the way in which these principles are understood is an
essential characteristic or property of a predicament.
90. Digression: the substance-accident distinction and
the theology of the Eucharist
A Catholic has a particular interest in this doctrine, because
it is very closely related to the theology of the Eucharist. Revela­
tion tells us that the apparent bread and wine of this sacrament
are the Body and Blood of Christ. Theologians say that the ac­
cidents of what was the bread and wine exist, by the power of
God, without inhering in their natural subjects.
It is of course important to remember that the distinction be­
tween substance and accident was first stated by Aristotle,
obviously in entire ignorance of the revelation to come. So it is
a purely philosophical doctrine. Secondly, it is important to see
that the distinction of substance and accident does not "explain,”
or make the sacrament “easy” for God. This much is true: if we
were to assert the identity of substance and accident, the revela­
tion would be unintelligible.

91. Definitions

Accident is that by which a being exists in some modified way,
that whose nature is to be in another, as in a subject.
Quantity is that by which a material substance has parts out­
side of parts.
Quality is the accident which modifies the manner of existing
of a being.
92. Readings

James S. Albertson, S.J., “The Esse of Accidents According to St.
Thomas,” The Modern Schoolman, XXX (1953), 265-278; a textual
study showing that accidents do not have a natural proper existential
act really distinct from the existential act of the rest of the being.

[89-92]

accidents; quantity; quality

237

St. Tilomas Aquinas, Summa Theologiae, Pt. I, q. 3, art. 6 (sub­
stance and accident in creatures and in God), q. 54, art. 3 (the dis­
tinction between substance and accident even in angels), q. 77, art.
1 (including the arguments and their answers; the distinction between
the substance of the soul and its accidents); Pt. Ill, q. 75, art. 5 (on
the accidents of the Eucharist); Pt. I-II, q. 53, art. 2, ad 3 (the
difference between the concrete and abstract accident); Truth, q. 3,
art. 7, ad 2 (concrete and abstract accidents); On the Power of God,
q. 7, art. 7, par. 1 (substance and accident as beings).
Clifford G. Kossel, S.J., “Principles of St. Thomas’s Distinction
Between the Esse and the Ratio of Relation,” The Modern Schoolman,
XXIV (1947), 93-99; this section is a very fine explanation of acci­
dent considered as a predicament.
Selected Passages from St. Thomas Aquinas

42. Proper Being, Predicamental Being,
and Being Which Is Truth.
Is is said in three ways. The first way is that in which it signifies
the truth of a proposition and is a copula; and in this sense . . .
“being” is an accidental predicate, and this “is” is not in the thing but
in the mind which joins a predicate with its subject. ... A second
way is that in which we speak of the esse which pertains to the nature
of the thing which is divided into the ten predicaments; and this
esse is in the thing, and is the act of being resulting from the prin­
ciples of the thing, as “lighting” is the act of “that which shines.”
Sometimes [in a tliird way] esse means essence, or that according to
which a thing is.
Commentary on the Third
Book of the Sentences, dis.
6, q. 2, art. 2.

43. Essence with Respect to Substance and Accident
Simply and in the first sense, only substances are defined, and
only substances have an essence. . . . But in a qualified sense, and
secondarily, other tilings also can be defined. For substance, which
absolutely has a quiddity, does not depend in its quiddity on another.
But accident depends on a subject, although the subject is not of the
essence of an accident, just as the creature depends on the creator,
and yet the creator is not of the essence of the creature, so that it
would be necessary to place an exterior essence in its definition. But
accidents do not have esse except by this that they are in a subject,
and thus their quiddity depends on a subject; and for this reason it
is necessary that the subject be placed in the definition of the accident,
sometimes indeed in the nominative, sometime in an oblique case.

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The subject is used in the nominative case, when the accident is
signified as an accident concretely with a subject, as when I say, "Snub
is a concave nose.” For then “nose" is placed in the definition of
“snub” as if it were a genus, to indicate that the accidents do not have
subsistence except from a subject. But when the accident is signified
in the abstract, after the manner of a substance, then the subject is
placed in the definition of the accident in an oblique case, like a
difference, as it is said, "Snubness is the concavity of the nose."
Commentary on Aristotle's
Metaphysics, Bk. VII, lect.
4 (ed. Cathala, Nos. 13521353).

44. Difference Between the Way of Knowing
and the Way of Being
A great mistake is made about forms, for the reason that many
judge about them as they judge about substances. This seems to
happen because in the abstract forms are signified after the manner
of substances, as whiteness, virtue and so forth. Hence, some, fol­
lowing the manner of speaking, judge about them as if they were
substances.
On the Virtues in General,
art. 11.

45. Existential Act and Predicamental Being; the Relation
of Substance and Accident to Existential Act
“Esse” taken in its second meaning is “the act of being inasmuch
as it is a being," that is, by which something is denominated actually
a being in the real order, and in this meaning, esse is attributed only
to those things which are contained in the ten genera. Consequently,
“being,” which is denominated from this esse, is divided by the ten
genera. But this esse is attributed to something in two ways. In one
way, [it is attributed] as to something which properly and truly has
esse, or is, and in this way it is attributed only to substance subsisting
by itself. For this reason, that which truly is, is called substance in
the first book of the Physics. But all those things which do not sub­
sist by themselves, but are in another and with another, whether they
are accidents or substantial forms or any parts whatsoever, do not
have esse so that they themselves truly arc, but esse is attributed to
them. In the second way, [esse is attributed to something] as to that
by which something is, as “whiteness" is said to be, not because it
itself subsists in itself, but because by it something has “a being
white.”
Quodlibet IX, art. 3.

CHAPTER XIII

The Formalized Accidents
93. Relation
So far we have considered the predicaments of substance,
quantity, and quality, which are similar in that they designate
the subject in itself. The remaining predicaments, relation,
action, passion, when, where, situs, and habitus, all refer to the
subject but either directly or indirectly include a reference to
something else. These predicaments will now be taken up in some
detail.
The dictionary defines “relation” as the mode (or way) in
which one or more tilings stand to another or others. In this
definition, the word “things” is taken in a very wide sense to in­
clude not only real things, but anything conceived or understood
after the manner of a thing. It can also be defined as the order
or respect (as in the phrases, “in regard to,” “in respect of”) of
one to another. In some cases, the whole reality of one thing is
referred to another, such that the relation is really the same as
that which is related. For example, the whole reality of potency
lies in its order to act; so, too, matter is real inasmuch as it is the
capacity of receiving form, essence is real inasmuch as it is
wholly ordered to the act of existing, and so on. Such relations we
call “transcendental relations”; we do not deal with them here,
for they arc only the things themselves which are related, and we
have considered them as constitutive coprinciples of being.
The relations we are interested in now are those which are
called “predicamental” relations. They arc first of all accidents;
that is to say, they do not constitute the reality of the thing
related but are something other than the substance of the thing
239

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[93]

itself. For example, a “father” is not constituted a being by his
relation to his child; a thing which is similar to another is not
constituted a being by being similar, and so forth. The relations
in these two examples are respectively “fatherhood” and “simi­
larity.”
In order that we can talk of a relation, there must be a subject
(for example, the man who is the father), a term (the child), and
the foundation, that by reason of which tlic subject is referred to
the term (for example, in our case, the generation of the child
by the father). If one of these three is missing, there is no relation
(for example, between two things which are in no way com­
parable there is no relation because the foundation is missing,
thus, “green,” strictly speaking, is neither similar nor dissimilar to
“cube root”—there is no foundation for a comparison).1
We can easily see that in some cases the subject, term, and
foundation are each real. In such a case we speak of a real
relation. In many cases, however, one of the three is not real
but is supplied by an act of the mind; for example, we can speak
of the “left” side of this paper, although the paper has no left
side, and there is nothing in the paper which gives it the founda­
tion for such a comparison to a man. In a man, we speak of a
left side, for there is a foundation in the bodily structure between
right and left. In other cases the term is not real; for example,
when we say “Elmer is as moody as Hamlet” or “as simple as
Li’l Abner.” In such cases, wc speak of a “relation of reason,” and
this kind of relation is a being of reason. (One of the relations
of reason which we can easily overlook is the relation of identity;
identity is a relation of reason because there is no term distinct
from the subject ).
Hence, relation is unique among the predicaments. For all the
other predicaments have to be real, whereas relation can be
real or not-real, and still be a predicament.2
1 On the function of the foundation in relation, see Selected Passages,
No. 47.
’On this point, see Selected Passages, No. 48.

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Our particular problem then is: What is ‘relation” considered
in itself? It is, of course, a predicate, and so something under­
stood, an intelligibility (a ratio). But our question means more
than tins; it means, Is a real relation as such and according to its
mode of intelligibility to be found in the order of being? Why
is this a problem? One easy way to see that this is a problem is
to consider the fact that the relation of a particular subject can
arise, change, and disappear without any efficient cause in­
fluencing that subject. For example, one white page of paper is
like another, but if the other turns brown with age, the white
page is unlike the brown one. The white page has changed from
like to unlike without any cause influencing the white page. How
can this be? Or again, there are thousands of eggs in existence,
all of which are like each other. When a new egg is laid, all the
other eggs are now similar to it. And how many relations of
similarity does each egg have? It seems foolish to say that there
are thousands of perfectly similar accidents in each egg, differing
only in their term, and it is impossible to say that there is a gen­
eral relation of similarity, because a general relation is abstract
and cannot be found in the real order but only in a mind. These
absurdities and impossibilities should be enough to show us that
the question has been wrongly understood.
Let us go back briefly to accidents. The intelligibility'-, "acci­
dent," which is mentally understood after the manner of a form
is variously and differently realized in existent material beings.
In saying that accident is conceived after the manner of a form,
we mean that it is thought of as a form or quasi form determining
and modifying a substance, in a way somewhat like that in which
substantial form determines and specifies matter. Since the in­
telligibilities which we thus conceive bear directly on real beings,
they are first-intention intelligibles.1
*3 This does not mean, how­
1 Recall that first intentions are knowledges of that which we know
directly, that is, of things or objects. Second intentions are knowledges about
objects as known and arc called “second” because they presuppose a
previous act of knowledge to be known; cf. above, sec. 82, n. 8.

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ever, tliat there is always in the real order a form or quasi form.
Both that which we understand and our manner of understanding
of first-intention intelligibles must conform in some way to the
real order; but this conformity is not mirror-like.
Let us recall a few examples. A quantified existent is quantified
by a real intrinsic act, a quasi form, really distinct from the sub­
stance which it modifies and determines. We speak of such an
act or determinant of a real concrete substance as an accidental
form, and, in this instance, our manner of understanding is direct,
for in the real order there is a determinant, a quasi form, modi­
fying an existing substance and making it extended. So, too,
qualities are understood as forms; we understand that in the red
rose there is a form, which we abstractly call "redness,” by which
that rose is red. Thus, quantities and qualities, which are de­
nominations understood after the manner of forms, are in the
real order quasi forms or forms modifying a concrete substance.
Now let us take up the predicamental accident, relation. Is
there in a material existent a form or quasi form corresponding to
the formal intelligibility, relation? It is true, that, like quantity
and quality, relation is understood after the manner of a form.
But what is there in the real order? For example, take these two
lines:
A -----------------B ------------------------------------

Obviously, we have here an instance of a real relation, “longer
than,” and “shorter than.” But are these formal principles inhering
in the black ink, in the same way in which the blackness inheres
in the ink? In the real order, there is line A, which is a collection
of substances; for the purposes of understanding the situation,
we will think of a being, which is one substance, one inch long,
and symbolized for us by A. Similarly, B shall symbolize another
substance which is a per se unit two inches long. A then is a
substance, intrinsically modified by the quasi-form quantity, so
as to be one inch long. B is a substance, intrinsically modified by

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another quantity, so as to be two inches long. Now it is the very
nature of quantity tliat any one quantity' can serve as the measure
of evcrj' other quantity. This nature of quantity is formalized and
actualized as soon as a mind apprehends these beings, quantified
as they are, as respectively “shorter than” and "longer than.”
This does not make these relations beings of reason. For what
is understood is completely real. In the real order, there are ( 1 )
two subjects, one for each of the relations: (2) two terms, one for
each relation: (3) the foundation, which in itself is a real prin­
ciple of the being and, at the same time, is such as to be “open”
to other realities of the same order.4* The intellect recognizes
them for what they are and understands the subject by reason of
the foundation, as related to the term of the relation.
But the way in which these three principles of relations are
understood is unlike the way in which they are in the real order.
Relation is understood as a kind of form which is between two
beings, and joins or unites them like a bridge or a rope.6 What is
there in the real order which corresponds to this intelligibility
conceived after the manner of a form? The answer is that there
is one real subject (a being) with a real foundation (quantified,
acting, or being acted on), and another real being. Correspond­
ing to the conceived form there is a situation which includes
several beings. Yet in a real relation what is understood is truly
in the real order. In a relation of reason, on the other hand, the
mind precisely contributes part of what is understood; that is,
either the foundation or the term.0
In the relations based directly on quantity, and in those which
4 See Selected Passages, No. 47.
‘Of. Selected Passages, No. 49.
•It is traditional to speak of the “esse” and the “intelligibility” (ratio)
of a relation. Real relations and relations of reason have the same intelli­
gibility ( that is, they are understood as involving a subject, foundation, and
term). But only a real relation has “esse.” This means, “Only of a real
relation is it true tliat there is in the real order a subject, a foundation,
and a term.” (In the real order, relation is not a distinct form inhering in
some subject; as understood, it is a formalization; evidently, a formalization
cannot exercise an act of existing.)

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arc based on quality through quantity, we have what may be
called a formal, static relation (“equal,” “larger,” “similar”).
These relations are pure intelligibilities and do not imply any
kind of unification of subject and term in tlie real order.
There are other relations which are not so purely formal and
which imply some kind of union between subject and term. These
are the relations based on passion and action. For example, l.et
us take tlie relation of “child.” A child is a human being who,
being a substance (the subject), has been produced in its being
by a parent (tlie term), so that at least for the beginning of its
existing it depends on another (the foundation). To be pro­
duced by another is in some sense to be connected with another.
Yet cause and effect are really distinct beings and do not by their
very natures involve each other. An effect “includes” its cause,
inasmuch as it is related to it; more precisely, inasmuch as it has
received some influence from it. Yet it is a really distinct thing
(according to its intrinsic principles of being). The child, con­
sidered in its intrinsic constituents, is a substance, with an act
of existing proper to it and variously modified by its inherent
perfections. But of this child it is also true that it is the child of
these individual parents. When this situation is seen as a whole,
immediately there is a relation. Again, tlie mind adds nothing to
what is understood.
Let us take another example of the reception of some acci­
dental perfection—let us say that the power of sight has been
acted on by an external visible object. The subject is the person
possessing the power; the term is the physical agent; the founda­
tion is the reception of tlie influence from agent to patient. But
note that a power is already ordered to the reception of such an
influence prior to the action of the agent; in other words, passive
powers are by their very nature finalized toward tlie correspond­
ing agents. Consequently, there is a union—not substantial but
accidental—through the tendencies of passive powers as well as
through tlie reception of influences from agents.
The relation of a cause to its effect is not as simply handled

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as that of an effect to its cause. For, as we have already seen
briefly and shall see more fully in the next section, the causality
of the causes which we find in immediate experience is really
distinct from them and flows from active (or operative) powers
which, as accidents, are really distinct from the substance of the
causes. Hence, in finite causes we can find the three elements of
a relation as real and as really distinct from each other. For ex­
ample, in the relation of “father,” as we find it among men,
there are (1) the man who is the subject of the relation; (2)
his active powers and his activity by which the effect is pro­
duced; (3) the really distinct effect, the child. However, if in
some being its powers and its activity are really identical with
its act of existing, then we could not find the three really distinct
elements which constitute a real relation. In God, the relation of
“Cause of the world” is a relation of reason, for we place distinc­
tions between the intelligibilities of power and activity although
there are really no such distinctions. For the same reason, all
relations of God to the world are relations of reason,7 even though
what wc understand in them is true.
In the case of finite agents, relations based on causality are not
merely formal, static ones. Like the passive powers, the active
powers of created things are finalized toward their objects. More­
over, active powers are tendencies, and so subject and term are
united—again accidentally—through the tendencies of active
powers toward their corresponding passive potencies. As we have
seen before, act-potency correlations are based on the very nature
of act and potency and, consequently, are not immediately and
directly prcdicamcntal relations. For example, the tendency of
any acid to react chemically with a suitable base is the very
nature of the active power of that acid. So, tendency and finality
are not predicamcntal relations but are based on essential actpotency correlations.
Furthermore, action and passion may be transitory (for ex7 Except, of course, such relations as are involved in, or are a consequence
of, the Incarnation.

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ample, the generation of a living thing), but the relations based
on them are permanent. How can this be? First of all, once it is
true that A has caused B, it is always true, and so from the view­
point of intelligibility the relation is permanent. But there is more
to it than this. In all material tilings, the cause in acting loses
something to its effect—not because it is a cause but because it
is a material thing. For example, in local motion and in heating
there is a loss of energy; in lighting, there is an emission of
photons; in chemical activity there is a loss of energy (electro­
magnetism and gravity remain mysterious). In the generation of
living things, there is a loss of some part of the material sub­
stance of the parent. Hence, a material thing is permanently
different once it has caused an effect. And, for its part, an effect
has its esse as received from its cause. This received esse remains
permanently a received esse (and this is true of immaterial
effects, like a created angel, as well as of material ones). Hence,
there is no question of relations based on passion or action ceasing
merely because the actions or passions have ceased. Moreover,
there are the basic, transcendental orders of active powers
toward passive and of passive powers toward active ones, and
these transcendental orders which are essential to the powers
remain as a permanent ontological substrate for predicamental
relations.
Thus, when we understand a complex situation by means of
the intelligible form of relation, what we understand is truly in
the real order: subject, term, and foundation. But the static rela­
tions based directly on quantity and those based on quality
through quantity only assert these elements and do not imply
any union of any kind between subject and term. However, the
relations based on action and passion, although they also express
in a unified way a complex situation of several beings, imply
over and above that an accidental union of subject and term
through finality, tendency, and activity.
One of the important divisions of relations is that into mutual
and nonmutual relations. By a mutual relation is meant one which

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is tile same from both sides of that which is related; examples of
such are similarity, equality, and the like. Nonmutual relations
are those which are different on the two sides of the things re­
lated, for example, parent and child, larger and smaller, and that
whole large group of relations which are real on one side and of
reason on the other; for example, a table is at my right hand
(real), but I am on the left of the table (of reason), or, I know
this thing (real), but this thing is known by me (of reason).
There are various foundations of relation. We have already
considered quantity and action and passion. Aristotle adds a
third (Metaphysics, Bk. IV, 1020b30-31), that of being measured,
as knowledge is measured by its object or a portrait is judged
by its faithfulness to the person. There are, of course, related
substances, for example, substances which differ specifically;
and related qualities, for example, similar or different qualities.
But substance and quality do not constitute independent founda­
tions for relation, except through quantity or action and passion.8

94. Action and passion

Motion or change is in that which is moved or changed and is
clearly the act (perfection) of that which undergoes change.
Motion or change is already in itself an intelligibility ; we under­
stand tiie total process from initial stage to term (at least rela­
tively in such instances as local motion), although what is
actually real at any moment of time is not the total process but
only one stage of it.
It is one and the same motion which is from the mover or
agent. Therefore, when we compare or contrast action and
passion, we are still referring to one and the same motion, not
* St. Thomas explains that substance and quality are absolute perfections;
that is, they are the perfections of the subject itself. Substance and quality
are related, either through quantity (so that we can speak of “one" or
“many” qualities, the “intensity” of a quality, and so on), or through action
and passion. See In V Metapliys., led. 17; In I Sent., dis. 26, q. 2, art. 2,
ad 4; In III Sent., dis. 5, q. 1, art. 1, qa. 1. Sec also, Selected Passages,
No. 46.

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two. Exactly the same thing is referred to in the real order when
I say “A moves 8,” and "B is moved by A,” although in the first
case action is predicated of A, and in the second passion is predi­
cated of B. Hence, action and passion are identical in reality
with the motion and with each other, but they arc different in­
telligibilities: for to be the act or perfection of the changing in
so far as that act is in the changing and to be the act of the
changing in so far as the change is from the agent are different
intelligibilities.9
Do not confuse this with situations which are expressed thus:
"A moves B" and "B moves A," because here two actions are
predicated of two different things. Likewise, “B is moved by A”
and “A is moved by 8”; here two (numerically) different passions
are predicated of two numerically different things. These arc not
identical in reality with each other.
To have the situation of action and passion in the real order,
only three “things” are required: an agent with an active power,
a thing in which change takes place, and the change itself caused
by the active power. Nothing else is necessary'; in particular,
there is no need for an acquisition or change in the agent.
Although motion or change is properly in the patient, we actu­
ally predicate the action of the agent. In doing this, we directly
understand and name one thing—the agent—from another which
is really distinct from it. We say, “An electric coil heats the
water,” though the heating is going on in the water, not in the
coil. (Of course, there are other things going on: the electric
current is heating the coil, and there is also some action of the
water upon the coil. But we are abstracting from these other
actions, and treating only the one action.) We understand the
coils influence upon the water in terms of something modifying
the coil, and this modification itself we treat after the manner
of a form. Hence, “action,” strictly speaking, is a construct, and
this kind of construct we call an extrinsic denomination (because
the agent is named—denominatur—from the change it pro* Cf. Selected Passages, No. 50.

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duces in the patient). Because action as a predicament is under­
stood after the manner of a form, action is a univocal predicate.
“Passion” is predicated in a similar way, for “passion” is
expressed in a predicate when we understand and name the
patient from a change in it produced by the agent. For example,
we say, “The house is being built by John.” (Distinguish this
predicate from the kind expressed in a sentence like “The house
is being built”; in the latter sentence, not passion but motion or
change is being predicated.) Hence, “passion,” strictly also, is
an extrinsic denomination (because the patient is partly named
from a reference to the cause of the change). Because passion is
understood after the manner of a form, it is a univocal predicate.
When we ask what is referred to in the real order, we designate
the motion or change in the patient. But motion or change is a
process-toward-the-act of being, and so is in the existential order;
change is a way to come to be. Thus, change in itself, in the real
order, is analogous. For example, one kind of change is alteration
(change of quality), another is augmentation (increase in quan­
tity), another is change of place, and so on. These various
changes arc different as changes, not by an external difference
added to them.
Likewise, there is an act in the agent which grounds its reality
as agent. This act in the agent is not its substantial form or its
act of being or a quality but the act of an active power, which
presupposes the act of existing. This act, concretely, is the
“agent in act,” or “the acting of the agent,” and is itself not a
univocal reality but an act which is analogous like the act of
existing. “Acting” is known directly in a judgment, in a verb of
acting (in a way similar to the act of existing), and we can have
a concept of action, not directly by abstraction from the thing,
for acting is by no means abstract; it is necessarily concrete and
existential. We derive our concept of action by a “second-level”
abstraction, from the judgmental knowledge previously expressed
in a verb.
Note carefully that action and passion are correlated and that

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consequently they refer only to transient action. That is why we
sometimes call transient action “predicamental action.” Immanent
action or operation strictly so-called is an act or perfection of
the agent; it is not of itself a means to anything else or a way to
come to be but an end. We see or understand, and so forth, and
these operations are the perfections of the seer, the knower.
Immanent action is like transient action only inasmuch as it is an
analogous kind of “acting,” the actuality of a power of immanent
operation.

95. When, where, situs, and habitus

The predicament where states the relation of one material
thing to others in regard to quantity. Note that where is not the
same as space. Space is a pure abstraction, namely, threedimensional extension abstracted from all accidental modifica­
tions, understood after the manner of a being in itself as a kind
of container into which material things are placed. Where, on
the contrary, is concrete. It designates a material thing (more
accurately still, a quantified thing) in relation to other material
things. But because where names one thing from other really
distinct tilings, it is an extrinsic denomination. Recall that ex­
trinsic denominations are not beings of reason; for what I name
when I say “here,” namely, this thing and other material things
and the contact (direct or mediate) between them, are com­
pletely real. But the way in which they are understood, that is,
like an inherent form, is a way of understanding.
When names the duration ( the continued existence) of a thing
in relation to the duration of some other thing or things. Strictly
speaking, the duration measured by when is a perfectly con­
tinuous duration, capable of indefinitely repeated division.
Hence, the duration which is the measure by which I name some­
thing to be now must be a continuous change, and that is why
local motion serves as a convenient measure. Distinguish when
from time. Time is a pure abstraction, namely, perfectly con­
tinuous and even successive duration (changing duration) as the

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measure (“number”) of motion according to the sequence of
priority and posteriority. When, however, is quite concrete; it
names one real duration in relation to another.
Situs is a very complex predicament, adding to where the
disposition or arrangement of different parts among themselves,
for example, “head” or “foot” in an animal, “top” or “bottom" in
a tree, and so forth. Note that the difference in the “different
parts” is a difference of quality (figure and so on). Now,
inasmuch as situs has tins arrangement or structure or organiza­
tion implied, to that extent it is an intrinsic perfection of the
thing itself (some authors call this “internal situs,” but more
accurately it is a complex quality). But inasmuch as the proper
notion of situs is a measure of the ordered parts in relation to
place, it too, strictly speaking, is an extrinsic denomination.
Habitus, finally, designates place in relation to some human
purpose, thus, clothed, shod, and so forth. Consequently, it is
also an extrinsic denomination, naming one thing from its rela­
tion to another distinct tiling.10
It will be noted that the predicaments which are extrinsic
denominations cannot be applied to one individual in isolation.
For example, if we supposed that only one material thing existed,
it would have no predicamental relations, no predicamental
actions or passions, would not be anywhere or at any time, would
not have situs or habitus.
It is to be noted also that the last four predicaments (when,
where, situs, and habitus ) all depend on quantity in one way or
another. Consequently, if there should be any nonquantified
beings (spiritual beings), such beings will strictly speaking not
be any where; nor will they exist during any portion of time; nor
will they have situs or habitus. Of course, we cannot imagine
such beings to ourselves, and we have to understand them by
analogy with the sensible things of our experience. Hence, we
will apply these predicaments to them, but we should understand
that this is done improperly.
*Cf. Selected Passages, No. 51.

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96. Definitions
Relation is the way in which one “thing” stands to another or
others. For the expression “stands to” we may substitute “is in a
certain respect to,” “is with regard to."
Transcendental relation is a principle of being whose whole
reality lies in its orientation to another. (For example, matter
whose whole reality' lies in its orientation to form.)
Predicamental relation is the accident by which one thing (the
subject) is contingently with respect to another (the term).
(For example, fatherhood, similarity.)
Real relation is a relation in which the subject, foundation, and
term are all three real. ( For example, fatherhood is a real relation
because the man who is the father, the person who is the child,
and the act of generation are all three real; similarity is a real
relation when the material quantified thing which is the subject
exists, the term also really exists, and the foundation is a real
modification of the subject.)
Relation of reason is a relation in which either the foundation
or the term is produced by an act of the mind. (For example,
the right side of a desk—the desk has two sides, the subject and
the term, but no foundation in itself for having one side called
“right.” Or we may say that a certain person is "as inaccessible
as Jupiter”—the person exists; no one can get to see him, but
Jupiter is not a real being.)
Mutual relation is one of a set of relations which are such that
the relation of subject to term is the same (specifically) as the
converse relation. (For example, if A is similar to B, then B is
similar to A; so, too, with equality.)
Nonmutual relation is one of a pair of relations which are not
the same in each of the pair of terms involved. (For example, if
A is larger than B, then B is smaller than A; if A is B’s father, B
is As child; if I know a thing, the thing is known by me—and
here the first is a real relation, the second a relation of reason.)

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Action is the change (motion) o£ a patient as from an agent.
Passion is the change (motion) of a patient as received (from
an agent) in a patient.
Extrinsic denomination is the understanding and naming of
one thing from another tiling really distinct from it.
When is the accident by which wc name the duration of one
thing from the continuous duration of another.
Where is the accident by which we name one thing from its
contact with other material things distinct from it.
Situs is the accident by which we name the internal order of
different parts of one thing in relation to where these parts are.
(For example, top, bottom, middle.)
Habitus is the accident by which we name one thing as being
in a certain situation in reference to a human purpose. (For
example, clothed, shod.)
97. Proof
In our experience there are real things (subjects) which must
be understood as related by reason of some intrinsic perfection
in them.
But: when the intelligibility (ratio) of a relation expresses real
and really distinct subjects, foundations, and terms, it possesses
all the elements necessary for a real relation.
Therefore: there are real relations.

98. Readings

St. Thomas Aquinas, On the Power of God, q. 7, art. 9, ad 7 (dis­
tinction between the esse and the intelligibility of a relation), q. 7,
art. 10, ad 8 (perfections which are not forms); Summa Theologiae,
Pt. I, q. 28, art. 1 (meaning of real relation), q. 29, art. 4 (on rela­
tion, especially in God).
Clifford G. Kossel, S.J., “The Esse and Ratio of Relation,” The
Modern Schoolman, XXIV (1946), 19-24, 30-36, 96-107; "St.
Thomas’s Theory of the Causes of Relation,” The Modern Schoolman,
XXV (1948), 151-172.

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Selected Passages from St. Thomas Aquinas

46. The Foundations of Relation
Since a real relation consists in a certain order of one thing to an­
other, relations of this kind must be found in as many ways as it
happens that one thing is ordered to another. But one thing is ordered
to another, either according to its act of existence, inasmuch as the
esse of one thing depends on another, and this is the third mode;
or according to active and passive power, according as one thing re­
ceives something from another, or gives something to another, and
this is the second way, or according as the quantity of one thing can
be measured by that of another, and this is the first way.
But the quality of a tiling, as such, regards only the subject in
which it is. Hence, according to quality, one thing is not ordered to
another, except in so far as quality has the nature of an active or pas­
sive power, inasmuch as it is the principle of action or passion; or be­
cause of quantity or something pertaining to quantity, as one thing is
said to be whiter than another, or as something is said to be similar [to
another], which has some one quality. But the other predicaments
rather follow relation than cause relation. For “when” consists in some
relation to time; “where,” to place; “position,” implies an order of
parts; “habit" a relation of that which has to that which is had.
Commentary on Aristotle’s
Metaphysics, Bk. V, lect. 17
(ed. Cathala, Nos. 10041005).
47. The Foundation and the Reality of Relation
Relation does not have an esse in the real order except from this
that it has a foundation in the thing, and from this foundation it is
found in a genus. Hence it is that the essential differences of rela­
tions are taken from the differences of other beings, as is clear from
the Philosopher (Metaphysics, Bk. V), who says, that some relations
arc founded on quantity, and others on action, and so on. A further
consequence is that the order of relations among themselves is accord­
ing to the order of those things upon which they arc founded. There­
fore, as we find that in those things winch are distinguished by their
essences, that the principles of their substance distinguish them
(namely, their matter and form), and other accidental things are
signs which manifest this distinction, so is it also in those things that
are distinguished by their relations, that the relations which are
founded on the nature of the thing are distinguishing, and other rela­
tions are signs of distinction. But the relations which have a founda­

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tion in the nature of the thing are the relations of origin, for father­
hood is founded in the communication of nature.
Commentary on the First
Book of the Sentences, dis.
26, q. 2, art. 2, ad 4.
48. The Esse of Relation
The intelligibility of a relation, like that of motion, depends on the
end or term, but its esse depends on the subject.
Summa Theologiae, Pt. Ill, q.
2, art. 7, ad 2.
It is to be noted, that relation is said to be in another way than
Other beings. For in other beings, any thing is said to be in two ways:
with regard to its esse, and with regard to the intelligibility of its
quiddity, as wisdom according to its esse places something in its sub­
ject, and similarly according to its intelligibility places a nature in
the genus of quality. But relation is something according to the esse
which it has in its subject, but according to its intelligibility it is not
a “something,” but only a being referred to another. Consequently
according to its intelligibility it does not place anything in its subject,
and this is why Boethius says that relatives do not predicate anything
of that of which they are said. Hence also it is that there is something
related in which there is only a relation of reason, and there is not
placed in it anything in the real order, as when the knowable is re­
ferred to knowledge. And this is true as well in the relations which
are predicated of God as in those which are in creatures, but in dif­
ferent ways, for the relation which has an esse in creatures, has an­
other esse than the esse of its subject, and so it is something other
than its subject. But in God there is nothing which has an esse dif­
ferent from it; for the esse of wisdom in God is the divine esse itself
and not something superadded, and similarly the esse of Fatherhood.
Consequently relation, as far as its esse is concerned—and this is the
only way in which it ought to posit anything—is the divine essence,
but according to its intelligibility, by which it has the function of dis­
tinguishing one person from another, to express something does not
belong to it, but rather [to express] “to something.”
Commentary on the First
Book of the Sentences, dis.
20, q. 1, art. 1.

49. Is a Relation Related to Its Subject?
. . . relations, by which a subject is referred to another, are not
referred to the subject by another intermediate relation, nor to the

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opposite; for example, fatherhood is not referred to either the father
or to the son by means of a relation; and if such relations are spoken
of, they are relations of reason.
Commentary on Aristotle’s
Metaphysics, Bk. V, lect.
20 (ed. Cathala, No.
1063).
50. Action and Passion
But if action and passion are the same in substance, it seems that
they are not different predicaments. But it is to be noted that the
predicaments are distinguished by the different ways of predicating.
Hence, tlie same thing, according as it is predicated differently of dif­
ferent tilings, belongs to different predicaments. For place, inasmuch
as it is predicated of the locating thing, belongs to the genus of
quantity, but inasmuch as it is predicated denominatively of the thing
located, constitutes the predicament “where.” Similarly motion, ac­
cording as it is predicated of the subject in which it is, constitutes the
predicament of passion; but according as it is predicated of that from
which it is, it constitutes the predicament of action.
Commentary on Aristotle’s
Metaphysics, Bk. XI, lect.
9 (ed. Cathala, No. 2313).
51. Not AU Denominations Arise from Forms
That from which something is denominated, need not always by
its nature be a form. It is enough that it be signified after the manner
of a form, grammatically speaking. For a man is denominated from
action and from his clothes, and from other things like this and these
really arc not forms.
On the Power of God, q. 7,
art. 10, ad 8.

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Correlations
99, Introductory note
A more accurate consideration of the nature of metaphysics
can be made now that tlie basic fundamentals have been con­
sidered briefly. It is also now possible to draw together some
elements which were first considered separately as they occurred,
and this is especially true of the doctrine of analogy. Finally,
more explicit comparisons can be made between metaphysics and
other knowledges and between St. Thomas and some other phil­
osophical positions.
This chapter is not intended to be taken in the ordinary class.
As occasion offers, some references may be made to it; the better
students can be directed to read parts of it and may even be
inclined to read it on their own initiative. Because of this pur­
pose, the treatment will be compressed and often schematic. It is
by no means claimed to be exhaustive.

100. Ontological and constructural knowledge

We have briefly seen that knowledge can be divided and
classified in many ways. We have seen that a knowledge is
specified by its subject and, most accurately, by the formal in­
telligibility of that subject—what is known precisely in the way
in which it becomes knowable to us. This formal intelligibility’
(ratio formalis objecti') is often called the formal object.
Many writers on philosophy apparently think that the formal
object is something entirely in the thing known, as it exists in
the real order. It is therefore necessary' to state explicitly what
257

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most Thomists (in fact, most philosophers) admit quite clearly
—in other contexts and connections. First of all, a sensible, ma­
terial thing is not actually intelligible1 either in what makes it to
be what-it-is or in what makes it to be simply, and therefore its
actual intelligibility must include the way in which it becomes
known to us. Secondly, immaterial, or spiritual, beings are indeed
actually intelligible to an intellect proportioned to them; they
are not directly intelligible to us but only by means of sensible
things in one way or another; therefore the intelligibility of
spiritual things for the human mind also includes the way in
which they l>ecome intelligible to it. That is why St. Thomas
speaks of the way of understanding (modus et ratio cognoscendi)
as well as of what is known in the thing.2 Since the knowable as
such (scibile in quantum scibile) is what distinguishes and
specifies a knowledge, we must take account both of what is
known and of our way of knowing it.
One aspect of the “way of knowing a thing” has become clear
only in recent centuries; it was not explicitly recognized even
by St. Thomas. Among Thomists, Jacques Maritain was the first
to give a detailed study of two different manners of knowing:
1 By the use of this phrase, “actually intelligible,” implicit reference is
made, first, to the common Aristotelian teaching that an intellect which
knows by way of reception of an influence from material things cannot
know them directly precisely as material (cf. G. P. Klubcrtanz, Philosophy of
Human Nature [New York, Appleton-Century-Crofts, Inc., 1953], pp. ISO184); secondly, to the equally common teaching that the contingent pre­
cisely as contingent is not the object of purely intellectual knowledge (for
the meaning of this teaching, see George P. Klubertanz, SJ., The Discursive
Power [St. Louis, The Modern Schoolman, 1952], pp. 192, 216-219, 248-2-54,
284-286); for the need of finding some necessity in the scientific considera­
tion of contingent things and the way in which this is done, sec the forth­
coming article of Joseph Owens, C.Ss.K., “A Note on the Intelligibility of
Being," Gregorianum, Vol. XXXVI (1955).
* For the modus cognoscendi—the way of understanding—note this list of
references given by Schütz, Thomaslexikon: Summa Theologiae, Pt 11-11, q.
48, art. 1; Pt. Ill, q. 9, art. 4, ad 1; In Boethii de Trinitate, lect. 2, q. 1,
art. 1, ad 3; q. 2, art. 1, ad 2, 3, 4; In I Sent., prologue, q. 1, art 5, c. In
Post. Analyl., lect. 1, princip., lect. 4, princip.; lect. 30, princip.; Truth,
q. 11, art. 1; In II Metaphys., lect. 5, med.

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"intuitive”8 (dianoetic) and “empiriological” (pcrinoetic)? Wc
shall refer to the two kinds of knowing as “ontological” and
“constructu ral."
An ontological knowledge is a knowledge that is directly and
immediately of the thing known according to the latter’s own
proper reality. For example, we can immediately sense and
understand 3 the shapes of objects that have definite outlines, and
in those shapes can directly understand some simple, direct re­
lationships—for example, seeing an extended thing like the page
of a book, we can immediately understand that this is a four­
sided shape, and that a part of such a surface is always and
necessarily less than the whole. Again, other simple qualities can
similarly be apprehended by us—colors, temperature relative to
our body, resistance of bodies. Moreover, in the presence of a
sensible object, we immediately understand that it exists—at least
under proper conditions of awareness.
* Particularly in his more recent writings, Jacques Maritain has been
using the term intuition. Inasmuch as this term is meant to indicate the
direct, nondiscursive character of the understanding, it translates intellectus
or intelligere. But the implications and connotations of the term seem to be
very unfortunate. What Maritain himself means by the term is not always
clear. He speaks of an “intuition of being” which is had suddenly after
long years of reflections; of an “intuition” of the existence of God. What is
common to these two acts is their nondiscursive nature. It does not seem
that either of them would have been called by St. Thomas an intellectus.
For this reason, this book dissociates itself from the term “intuition” and
uses instead terms like “insight,” "direct understanding." What is meant
by insight in this book has been explained several times; see also below, nn.
6 and 15.
4 For this distinction, see Jacques Maritain, Degrees of Knowledge, trans,
by Bernard Wall and Margot Adamson (New York, Scribner’s, 1938), pp.
248-252; “On Human Knowledge,” Thought, XXIV (1949), 225-243.
The correspondence between this distinction and F. S. C. Nortluop’s
“concepts by intuition” and “concepts by postulation” is not so close, prin­
cipally because of what Professor Northrop means by “intuition.”
sTo understand does not mean “to name,” or necessarily, “to define”;
it certainly need not mean “to have a scientific knowledge of.” In particular,
if we see an object shaped like
, we can understand at once
that it has such a shape, without being able to name or describe it, much
less define it. This is by no means a mathematical, abstract knowledge; the
experience is direct, immediate, and concrete.

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Furthermore, ontological knowledge reaches to some minimal
knowledge of natures: at least that this thing before me is a
material thing, for example. To some extent, wc have a direct
ontological knowledge of what “man” is and of what “knowledge”
is. Such direct knowledge is a knowledge of nature or essence,
and it is very limited. We know the essence of man quite well;
of living things generically; of most other tilings according to
some remote genus (for example, as material substance). We
also know that there are really distinct individuals and different
kinds of things, whatever the differences between them may be.
Still further, we have an immediate knowledge of activity as
a special kind of reality different from form, essence, and even
the act of existing, although our first knowledge of these dif­
ferent kinds of reality will be very vague and inexpressible in
words. Nevertheless, this knowledge is a direct knowledge of
the thing known in its own terms. Together with this direct
knowledge of activity we also have an immediate apprehension
of change and causality
*
(again, at least in some instances); we
experience some things causing other things, for example, our­
selves causing something to happen.
So far, we have instanced kinds of ontological knowledge in
the mode of immediate experience. We can also have ontological
knowledge of some conclusions which are no longer immediate.,
in the sense that their objects are not experienced in themselves.
These conclusions can still be ontological in character, provided
that all the terms entering into the reasoning process are directly
ontological, that the reasoning itself is direct (that is, is either
direct deduction, direct induction, or a direct fact-proof [demon* This is not knowledge at the level of the philosophy of nature, or even
strictly, of principles proper to that branch of philosophy. This knowledge
is much more a direct knowledge presupposed for all philosophy. That this
is direct knowledge prior to philosophy is explicitly admitted by Father
Kane, in William H. Kane, O.P., Benedict M. Ashley, O.P., John D.
Corcoran, O.P., and Raymond J. Nogar, O.P., Science in Synthesis (River
Forest, Dominican College, 1952), pp. 197-198.

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stratio quia]), and that the reasoning proceeds according to the
directly ontological character of the terms involved.
Hence, the method of ontological knowledge is (a) intelligible
induction and direct insight;7 phenomenological description/
that is, direct, noninterpreted description; and (b) direct reason­
ing (as described above), that is, not hypothetico-deductivc and
not resting on extraneous elements.
Must there be some ontological knowledge? Yes, if there is to
be any knowledge of reality at all. Otherwise, we would be in
a complete subjectivism. This will become clearer if we take a
look at constructura! knowledge and see how it is developed.
Let us first look at pure constructura! knowledge. Of course,
there is no object of the human mind which is absolutely and
entirely constructed by the mind without even any point of de­
parture in experience. Mathematics offers the simplest and one
of the best examples of a purely constructura! knowledge. Given
the barest starting point in experience—we are not concerned
here with establishing the fact, much less with the way in which
mathematics is originally connected with experience—the mathe­
matician proceeds to construct mentally his figures, formulas,
functions, and symbols. In constructing the objects of his knowl­
edge, he knows them, or, conversely, he knows them by con­
structing them. These “mathematicals,” as we may briefly call
mathematical objects in general, do not exist; their being is a
being-known; they are beings of reason. When someone formally
’These terms, especially the latter, are used in many senses. For the
precise way in which they are used here, sec Klubertanz, Philosophi/ of
Human Nature, pp. 385-401; Robert J. Henle, S.J., Method in Meta­
physics (Milwaukee, Marquette University Press, 1951). Note that the term
“insight” is sometimes used by experimental psychologists as equivalent to
“interpretation”; interpretation, however, seems to be a clear case of con­
structum! knowledge.
•See John Wild, Return to Reason (Chicago, Henry Regnery, 1953),
pp. 35, 37-38, 48-49. Our acceptance of the term phenomenological does
not imply that "phenomenology'” as a distinct kind of philosophy is a part
of Thomistic metaphysics, or even that it can be adapted or harmonized
with it.

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knows one of these “mathematicals,” what he knows is precisely
the mathematical and nothing else,0 that is, the object con­
structed by him. The only laws that a mathematical is subject to
are the laws of intelligibility: definability or constructability,
consistency, and the like. So much for pure constructural knowl­
edge; let us now consider the constructural knowledge of the
real.
Constructural knowledge of the real has several characteristics.
It is first of all—at the level of scientific knowledge which is our
main concern here—selective (“abstractive”). The scientist con­
centrates on some particular and, therefore, selected evidence,
and what is selected is univocal, “literal.” This is a general re­
quirement; it is strongly reinforced if instruments are used which
by their nature allow only for certain types or kinds of activity to
register. Therefore, constructural knowledge is of a whole accord­
ing to some partial aspect; and, under this first consideration, the
“constructurality” consists in this: that the partiality of evidence
and reporting is understood and stated as if it were a total report.
Secondly, constructural knowledge of the real arises by rational
induction.10 We have already noted that ontological knowledge
is severely limited in scope. In very many cases, we observe a
fact, an event, and so forth, and all we understand is that this
event occurs, once or several times; we see no connection that is
directly intelligible. Hence, we are forced to a roundabout way of
reasoning to come to anything like a general knowledge. We
argue that wc have hold of a necessity, on the ground of a rela­
tive consistency in an agent that is nonfree at least in this activity;
we may also need statistics to achieve the generalization.
Thirdly, and most characteristically, constructural knowledge
’Obviously we must distinguish mathematics as a science from such
quite different operations as counting and measuring real things. This
latter kind of knowledge is not constructural and seems to be prior, not
posterior, to mathematics as a science.
10 For a fuller explanation of the term rational induction, see Klubertanz,
Philosophy of Human Nature, pp. 385-401.

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is indirect, that is, the knowledge of one thing in terms of another.
This “other” is a construct or substitute-object. Now there are
several types of constructs. An example of the first is in use when
we understand the subatomic components of atoms in terms of
“particles.” Unless we had met a particle in direct experience,
this word would be meaningless. Moreover, a subatomic particle
is not a particle in the directly experienced sense of “particle.”
But the point is: if we conceive an atom as composed of particles,
we can set up relationships between these particles that
correspond with the selectively observed behavior of atoms. This
kind of construction is construction in terms of a sensible model.
We can also make a construct in terms of nonsensible objects.
Here, we begin with pure constructions, that is, with objects
whose whole reality arises from their being built in such a way
by the mind. Pure constructions are a special kind of knowledge
all by themselves. But they can also be used instrumentally in
the knowledge of the real, and when they are so employed a
constructural knowledge of the real is obtained. Thus, mathemati­
cal physics is a constructural knowledge, in that it uses mathe­
matical entities (as well as other types of construction) in the
understanding of the real.
A third kind of construct is the operational definition. This is
knowledge, not precisely of the thing but of what we must do to
acquire “it” in the real order, whatever “it” may be. For example,
“chlorine” is what you get at one of the poles in the electrolysis
of salt water. Tins is a useful definition, and it has some connec­
tion with whatever “chlorine” is in itself, but the definition docs
not reveal that connection; such connection, if it is had, may be
made by means of a model construction.
A fourth kind of construct consists in obtaining a surrogate of
an essence or nature by the selection of what seems to be the
most consistent of the various several attributes of a thing, which,
at the same time, enables us to put some order into the rest of the
attributes.

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The third stage in construction—that of the four types of con­
struction strictly so-called—is what is typically characteristic of
constructural knowledge. It is by no means an arbitrary proceed­
ing. At the very least, tlie construct must be verified—conse­
quences deduced from the construct must be found to hold good
in the real order. For example, the quantitative relations pre­
dicted by a mathematical formula in thermodynamics must be
observed (verified) in the physical process. A closer type of
relation is to be found in more physical theories which have some
elements of description, or model, in them; here, the theory
must not only provide good predictions but also must have some
similarity with what is described, in so far as we know anything
about it. For example, the atomic theory as a whole has many
aspects which come closer to being descriptive than merely
theoretical.11
101. Metaphysics, experience, and spontaneous knowledge
In the first chapter, we have seen that descriptively meta­
physics is a kind of knowledge that differs from other kinds. The
question readily arises: "What is the relation between meta­
physics and these other kinds of knowledge?” Because there are
various modes of knowledge and many distinct kinds of sci­
entific knowledge, we must consider them one at a time in their
relation to metaphysics. The relations in question are principally
those of priority and dependence.
Does metaphysics depend on other knowledge? In other words,
does metaphysics have any presuppositions? In one sense, meta­
physics cannot have any presuppositions. It is a demonstrative
knowledge of all being, and so no being is beyond its scope.
Moreover, there cannot be any other knowledge which is strictly
and formally presupposed by the ven' nature of metaphysics
u In fact, the atomic theory even has some ontological elements within it;
see George P. Klubertanz, S.J., “The Teaching of High School Chemistry,"
an article to appear in the Journal of Chemical Education (1955).

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itself; Aristotle called it ‘’first philosophy”; and we can say that
whatever tlie scientific knowledge is which rests on no other
knowledge, that is metaphysics.
In another sense, metaphysics cannot be the first knowledge.
Aristotelian metaphysics—the first fully conscious attempt to
build a metaphysics—was intended to be the last knowledge
gained by a man. Formally, Aristotelian metaphysics rested on
Aristotelian “physics." This historical fact has influenced other
thinkers to say that metaphysics formally depends on other
knowledge. Again, St. Thomas has explicitly said that meta­
physics cannot be learned by a juvenile mind; a mature person
is the only one who is capable of learning metaphysics. Usually
some experience and at least a broad acquaintance with science
are required before a student can successfully attack meta­
physics. And, indeed, it would be totally impossible to begin the
study of metaphysics without any preceding knowledge.12
The relation between metaphysics and spontaneous knowledge
is further complicated by tlie fact that many statements (for
example, that a real world exists, that there are real causes of
sensible effects) seem to be found both in spontaneous knowl­
edge and in metaphysics. And some knowledge of this kind
necessarily exists in a person before he has had an opportunity
to study metaphysics. What is the relation between the two
knowledges? Or are they perhaps identical?
12 The old adage says that whatever is in the intellect was first in sense-—
prius in sensu. Many Thomiste (and others, too) seem to think that sensa­
tion and intellection are two distinct operations going on in us and somehow
correlated; that sense precedes intellection in time; and that there is only a
causal connection between the two operations. Introspection and analysis
both show that as Far back as a human being can recall, and clearly in adult
life, human conscious activity is sensory-intellectual at once. There is no
priority in time of sense over intellect to be discovered; only an analysis can
discover the distinction between the two kinds of activity. Hence, to the
objection, “Prior to metaphysics there is sense experience," tlie answer is,
"Sense is indeed a cause of intellection, but sense experience is not an
activity temporally prior to or descriptively distinct from intellection;
perception is descriptively a single unified experience in which analysis
discovers sensation and intellection."

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We can begin to solve this problem if we reflect on the kind of
evidence that metaphysics rests on.13 /\s we have seen, meta­
physics rests on immediate or perceptual knowledge.14 We find
in immediate experience the presence of sensible being, and
sensible being is the starting point of all metaphysical knowl­
edge. Note that we do not derive this principle (namely, being)
from experience; we find it in experience. We do not say, “We
found being in our spontaneous knowledge, let us now analyze
that knowledge.” True, we did find (sensible) being in spon­
taneous knowledge; then it was accepted unreflectively and with­
out any relation to anything else. When we begin metaphysics,
we begin with a very careful description of sensible being. This
preliminary description is carried on with a constant reflection on
the evidence, looking at what we find and trying to understand
and express it to ourselves bit by bit in harmony with what we
find, no more and no less. This is a highly self-conscious process,
quite different from the procedure of spontaneous knowledge.
Secondly, the metaphysician studies sensible being from the
point of view of being as being, and this formal consideration
gives quite a special character to metaphysical knowledge. From
this description, the metaphysician continues on to an analysis of
the structure of that being (the constitutive principles of being),
still in the light of that same formal intelligibility. The analysis
of the structure of sensible being as being leads to the discovery
of the existence of the cause of that being, that is, to the exist­
ence of God. The rest of metaphysics consists in pushing further
the implications of these basic discoveries ( the properties of beu For textual and historical studies on the nature of metaphysics as here
expressed, see George P. Klulx-rtanz, S.J., "The Teaching of Thomistic
Metaphysics.” Gregorianum, XXXV (1954), 3-17, 187-205, and “Being and
God According to Contemporary Scholastics," The Modern Schoolman,
XXXIII (1954), 1-16; Elizabeth G. Salmon, “What Is Being?” Review of
Metaphysics, VII (1954), 613-631; Joseph Owens, C.Ss.R., “A Note on the
Approach to Metaphysics,” The New Scholasticism, XXVIII (1954), 454476.
“ By perception and perceptual knowledge we mean the total, unified
activity whose object is an existing thing present to our senses and attended
to by us; it is neither purely sensory nor purely intellectual.

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ing, the transcendental; our predication of being, the categories,
or predicaments; what is entailed by the nature of God as sub­
sistent esse, the Divine attributes; and what can be elaborated
concerning the relation of the world to God, creation, providence,
the co-operation of God with creatures, the Divine foreknowl­
edge, and so on).
Spontaneous knowledge, for its part, consists partly of imme­
diate experience, partly of some relatively simple, nontechnical
conclusions derived from experience. Therefore spontaneous
knowledge contains in some way the starting point of meta­
physics. But only “in some way”—not as the metaphysician uses
it. Spontaneous knowledge has no reflexly conscious point of
view; it takes immediate experience as it finds it, obscure and
confused. Secondly, spontaneous everyday knowledge reaches to
some understanding of sensible being, to principles understood
in a rough, or gross, unrefined sense. Among these principles we
find the principle of epistemological realism (understood rather
vaguely and generally), the principle of the plurality of distinct
individuals in the world, the principle of the diversity of the kinds
of being (“kinds” or “species” understood in a very vague way),
the principle of change, of the diversity of the kinds of change,
and of causality within change.15 Thirdly, spontaneous knowl­
edge includes some conclusions, such as the immortality of the
soul and the existence of God ( both of these understood not only
vaguely but also through metaphor).10 This part of spontaneous
**Cf. n. 5. The listing of principles here is not exhaustive. We should
also include such items as the knowledge of obligation and of the difference
between right and wrong, the notions of right and duty, of truth and
falsity.
14 In principle, there is no error in this kind of knowledge, for it rests on
immediate evidence that is presented to the mind without the need of any
investigation. It is not a careless or haphazard knowledge, even though it is
not gained by a conscious methodology; for in this kind of knowledge over­
whelming or massive evidence takes the place of methodological attention.
Therefore, this knowledge is valid, tliat is, is true and certain; it needs no
later justificatiou or validation; consequently, also, philosophy need not
begin with a universal doubt (and cannot so begin). But in fact spon­
taneous knowledge also includes much opinion, error, and sheer fantasy.

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knowledge is both true and certain, although the certitude
corresponds to the kind of knowledge we have and is only
analogous to scientific certitude.
The relation of metaphysics to spontaneous knowledge there­
fore is somewhat complex. /Vs far as the starting point of
metaphysics is concerned, it is contained within spontaneous
knowledge materially (it is not understood under the same in­
telligibility); it is not simply accepted from experience but is
re-examined within experience with great care and in the light of
being as being. As far as the principles are concerned, in the first
place, the principles of metaphysics and of spontaneous knowl­
edge are only materially identical. (Two propositions are mate­
rially identical when they have the same subjects and predicates
—the same, that is, when they arc considered apart from any
added meaning they might have from their connection with a
particular formal object of a habit, with particular principles, and
with preceding reasoning on which they depend. St. Thomas calls
a proposition isolated in this way a “position.”) In the second
place, metaphysics does not accept its principles uncritically from
experience. There is, it is true, a special difficulty with metaphysi­
cal principles. The understanding of being which is expressed in
the principles mentioned above is difficult to bring to awareness
because of its great generality'. They arc implicit in all experience,
it is true, but, because they pertain to all experience, attention
cannot be focused on them by isolating them. Therefore the ordi­
nary techniques of discovery are unavailing. These principles
come to explicit awareness only by the sheer “massiveness” of
their evidence, and this ordinarily takes quite a few years of
experience and a sufficient maturity of the physical organism to
permit some more than momentary' reflection. Metaphysics thus
presupposes a confused and general knowledge of its principles.
But these principles are not blindly accepted by the metaphysi­
cian; the student of metaphysics carefully re-examines the deriva­
tion of these principles from sensible being directly in some
experience of being, and in so doing brings to explicit knowledge

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their own intrinsic evidence (or “self-evidence”). This process
wc have called “intellective induction.” 17 Thirdly, spontaneous
knowledge includes some conclusions which arc materially iden­
tical (as positions) with some conclusions of metaphysics, and
chief among these is the existence of God. Again, metaphysics
does not merely accept this conclusion. Neither does it reject or
doubt it. But unless a person already has some knowledge of
God in some way and firmly accepts His existence, it is ordi­
narily impossible to deal intelligently with the proof of His exist­
ence.18 The human mind ordinarily cannot come to a knowledge
of God in a single act—at least not to such a knowledge as would
enable it seriously to inquire into the grounds of such knowledge
or to investigate the Divine nature. Briefly, we can say that meta­
physics neither accepts nor rejects the conclusions of everyday
knowledge but critically examines the reasoning (which everyday
knowledge did not do and could not have done) and very care­
fully determines the sense of the conclusion in the light of being
as being.

102. Digression on “common sense”

Those who are familiar with other discussions of the problem
raised in the preceding section will have noted the absence of the
term “common sense.” Sometimes, it is true, the term “common
sense” means precisely what we have designated “spontaneous
knowledge." In that case, the question, “What is the relation
between metaphysics and common sense?” will already have been
answered in our own terms of spontaneous knowledge. But this
” By an “intellective (intelligible) induction” we mean an intellectual
understanding that is gained in experience by an insight, direct, nondiscursive understanding of a concrete, sensible instance present to us. See
the references given in n. 7; see also Edmund H. Zicgelmeier, S.J., “The
Discovery of First Principles According to Aristotle,” The Modem School­
man, XXII (1945), 132-138.
“That is why an atheist, a skeptic, or an emotionally disturbed person is
not convinced by anry proof of the existence of God. To doubt a proof
because atheists reject it is to confuse rational necessity with subjective con­
viction. See also below, sec. 105.

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[ 102 ]

very' special meaning of “common sense” has been avoided in this
book for two reasons: one drawn from ordinary usage, the other
from historical considerations. In our ordinary usage of the terms,
sense, good sense, and common sense, we imply practical knowl­
edge.10 But metaphysics (and all philosophy except ethics) is not
practical but theoretical, speculative, or pure knowledge. So, in
answer to the question, “What is the relation between meta­
physics and common sense?” we can say, “There is no direct re­
lation.” Common sense bases its practical judgments on experi­
ence and some simple inferences. Metaphysics is a speculative,
scientific discipline concerned with the real as real. Indirectly,
there is this relation: metaphysics is the elaborated, demonstra­
tive knowledge of much of what is presupposed for common­
sense judgments.
The historical meaning of common sense is complex. In one of
the periodic reactions against a philosophy that had departed
very far indeed from the common understanding of men and was
even questioning whether either the philosopher himself or the
world he claimed to know could significantly be said to exist, the
seventeenth- and eighteenth-century realists came up with a new
solution. Granting that reason could not know its own existence,
the existence of a sensible world, and the like, these philosophers
found a way out: they said that man possessed a faculty called
“common sense” whose object was precisely these and similar
truths. The solution was attractive; it would guarantee what, in
fact, we all (somehow) know to be true; it was even tempting,
because it would free us forever from the necessity of having to
study and consider all other philosophies. Of course, in the sense
of a distinct faculty, “common sense” could not be accepted by
Thomists; so they identified “common sense” as “intellect working
** According to Webster’s New International Dictionary, 2d ed. (Boston,
G. & C. Merriam, 1953), “common sense” lias as its second meaning “Good,
sound, ordinary sense; specif., good judgment or prudence in estimating or
managing affairs, csp. ... as not dependent on special or technical
knowledge” ("3. Phil. b. The unreflective opinions of ordinary men").

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on obvious and necessary truths.” But the historical specter of the
Scottish realism followed the term about in spite of the attempted
correction.
Moreover, the Thomists have compounded the problem of
“common sense” on their own. Many of them were looking for a
“starting point” for philosophy, and they wanted a ready-made
one, a critically justified one, and one against which other philo­
sophical positions could be compared and accepted or rejected as
the case might be. The most widely accepted solution was that
the human mind spontaneously and immediately knew three fun­
damental truths (the first principle—of contradiction; the first
fact—“I exist”; the first condition—the ability of the mind to
know truth).20 On the face of it, the intent of these philosophers
looks perfectly sound; its real value lies in this: that they cor­
rectly realized the need for some starting point. For, if a philoso­
phy must begin by justifying its very existence, then it never
begins; the demand for total self-justification of a philosophy as
its first step toward being is the demand of a skeptic. Basing phi­
losophy on “common sense” eliminates an infinite regress in the
search for a foundation, but it brings about new problems. Some
of the utterances of "infallible common sense” arc uncouth, and
some are obviously wrong, so philosophy shall have to choose
among them. But on what basis? On the basis of common sense
itself? Those who chose to take common sense as their starting
point21 had to answer the objection that they were dogmatic,
likely to be fixed forever in error, at variance with the ancient tra­
dition that philosophy is an inquiry into every object, not merely
an inquiry about some objects. Moreover, science had made its
“On this whole question of Thomistic epistemologies, see Georges van
Riet, L’Epistéinolouie thomiste ( Louvain, Institut Supérieure de Philosophie,
1946).
11 For one of the few good treatments of “common sense,’ sec Yves
Simon, Traité du libre arbitre (Liège, Sciences et Lettres, 1951), pp. 59-69.
Unfortunately, the wrong connotations and historical associations of com­
mon sense” cannot be avoided even by one who treats the real problem
intelligently and well.

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progress precisely inasmuch as it got rid of common-sense notions,
and this was especially true of astronomy. Was philosophy to lose
entirely its scientific character?
Tins approach did not please other Thomists.22 They were
struck with the obvious inability of common sense to make the
critical judgments it was alleged to be making all the time. They
saw that if common sense needs to be corrected, it cannot be the
starting point and the criterion of truth. So they wanted to begin
by rejecting common sense, as the only alternative to accepting it.
But if one rejects common sense, one must find some area that is
outside common sense, and only two such starting points seem to
be available. One is the conclusions of science, and this starting
point has always been, and is now, the starting point of positiv­
ists, and remains that. In a later section, we shall consider the
relation between metaphysics and science which is abstract and
constructural. So we need not delay long here to explain why
science is not a starting point of metaphysics. The other starting
point outside the area of common sense is the basic concept of
metaphysics, the concept of being, of reality, of intelligibility, or
whatever a particular kind of philosophy has taken as its basic
concept. This starting point has always been that of rationalists
and of idealists; it cannot be the starting point of realistic meta­
physics; at best, such realism would have to be mediate, and at
this late date it scarcely seems necessary to show that mediate
realism cannot stand up. From this historical consideration the
conclusion seems to emerge that both the acceptance and the re­
jection of common sense make a realistic metaphysics impossible.
Hence, it seems much better to avoid the term entirely.
Closely related to the discussion of “common sense” is the at­
tempt to clarify the starting point of philosophy in terms of “com­
mon experience.”23 The sciences, by way of contrast, are said to
“ On this point, see Louis-M. Régis, O.P., “La critique thomiste est-elle
thomiste?" Etudes et recherches, Philosophie II (Ottawa, Collège Domini­
cain, 1938).
** This term was popularized by Mortimer J. Adler; see his W'/tot Man
Has Made of Man (New York, Longmans, 1937), p. 139.

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originate in “special experience.” The choice of terms has unfortu­
nate connotations. First of all, there is somewhat of a subjectivist
flavor in the term, particularly since “experience” seems to be
some sort of primitive and absolute reality when we do not stress
die fact that experience is the immediate knowledge of being.
Secondly, the use of “common and special” as alternative designa­
tions seems to suggest that whereas science is based on method­
ological, careful, critical, highly accurate, and selective data, phi­
losophy is based on opposite grounds, that is, on haphazard,
careless, inaccurate, unrefined data. This is how the distinction
has been understood by many, and so they have concluded that
philosophy might perhaps have some value as a preliminary stage
prior to science but that it should yield to the more careful re­
sults of the sciences. So the term “common experience” also
seems misleading and inappropriate.

103. Metaphysics and humanistic knowledge
( liberal education )

In examining, in the first chapter, human knowledge as it in
fact presents itself, wc discovered that it exists in three modes:
that of spontaneous knowledge, that of humanistic knowledge,
and that of scientific or demonstrative knowledge. We want here
to consider the relation between the humanistic mode of knowl­
edge and metaphysics; for this purpose we can briefly summarize
the characteristics of humanistic knowledge. It is characterized
by its effort toward the integration of knowledge through prin­
ciples and through its appeal to the human being as a whole—
as a sensory as well as a rational being, as a being with sensory
emotions and rational tendencies as well as one with knowledge.
As such, humanism is a distinct mode of human perfection, which
cannot be omitted without harm to the development of the per­
sonality and cannot be substituted for or replaced by any other
kind of perfection, without loss. Because it is a development of
the total personality, humanism has an intrinsic value, and is by
no means merely an instrument for other values. In fact, for many

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persons, humanistic perfection is terminal as far as the natural
development and training is concerned.
In the liberal subjects, especially in literature and history, we
find many things which arc materially similar and sometimes even
materially identical with the principles and conclusions of phi­
losophy. For example, we might consider the humanistic presen­
tation of the dignity of man; similarly, the drama of human free­
dom, the dilemma of choice, the difference between right and
wrong are found in a marvelously rich fashion in the humanistic
mode of knowledge.24 Are tírese characteristic understandings
different from philosophy? If we put the question concretely, we
can see that they are. Can the understanding of man presented
in Macbeth be successfully put into the scientific mode of phi­
losophy or psychology? Can Newman’s The Second Spring, be
adequately expressed in a graph, or the Sonnets of Elizabeth
Browning be reduced to a series of experiments? Obviously they
cannot; and, since this is so, the humanistic mode of knowledge
must be admitted to be different from any scientific mode.
What is the relation of such humanistic understandings to the
similar philosophical understandings? Both types of understand­
ings rest immediately on experience and, therefore, not on each
other. In this sense, the two are mutually independent. The prin­
ciples of humanistic knowledge are essentially the same as the
principles of spontaneous knowledge, but refined by some reflec­
tion and experience; they are concretely conceived and stated in
a highly concrete and vivid way. In addition, where the princi­
ples as spontaneously conceived are vague or indistinct, in hu­
manistic knowledge they are amplified and made definite through
metaphor and imagery. What is more, in spontaneous knowledge
the principles arc present but scarcely function at all as princi­
ples; spontaneous knowledge remains fragmentary, disconnected.
In humanism, the principles already present in spontaneous
* Much of both the Old and the New Testaments will be found to be in
the humanistic mode. For example, consider the discourse of Jesus at the
Last Supper as given to us in St. John’s Gospel and see if this can be ade­
quately expressed in technical, scientific terminology.

[103]

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275

knowledge but unused are put to work to organize and unify.
Inasmuch as humanistic knowledge is involved with what is con­
crete and sensory-imaginative, it will present through direct prin­
ciples, metaphor, and imagery what philosophy considers on a
purely cognitional-rational basis. But because humanistic knowl­
edge is so highly concrete and so charged with emotion, it is
incapable of clarification and of defending itself against certain
kinds of attacks especially from technocrats, and error can easily
be mixed in with its truth.25 In tins sense humanism needs meta­
physics, not precisely as a necessary intrinsic constituent but as
an external norm possessed by at least some who also have the
humanistic perfection.
On the other hand, though humanism is not by its nature a step
on the way to metaphysics, a liberal education is in fact a good
preparation for the study of philosophy.26 For the personal ex­
perience of every man is very limited, and in many cases, if one
could call only on that purely personal experience, it is doubtful
if even a whole lifetime could provide him with all the experience
necessary for an adequate understanding of philosophy. It is well
known that in the absence of experience, a merely verbal and
abstract presentation will never provide an insight into reality.
But the humanistic presentation is far more than merely verbal
and it is concrete; it can provide an imaginative reliving of an­
other’s experience, and this contribution is notably great with
respect to the philosophy of human nature and to ethics. By pro­
viding such a great enlargement of experience,27 a liberal educa
*
• Note that an understanding which is essentially metaphorical can never
be used as a premise in a philosophical argument and cannot simply be
turned into a philosophical statement.
•The method of discovering a philosophy by investigating the "Western
tradition” or canvassing the “great books” is essentially fallacious as a
philosophical procedure: (a) it confuses humanistic and philosophical
modes of knowledge; (b) it supposes there is a “least common denomi­
nator”—the “philosophia perennis”—which can be discovered by a poll of
philosophers.
” An enlargement which, incidentally, was scarcely known to St. Thomas
himself.

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tion can make a successful study of philosophy possible much
sooner than private experience could possibly do.

104. Metaphysics and other scientific knowledges

There are many contemporary philosophers who are of the
opinion that philosophy is built on the conclusions of some sci­
ence or of all the sciences or on the specialized, interpreted evi­
dence of the sciences. Still others think that metaphysics at least
is built upon the conclusions of the philosophy of nature.
Can metaphysics be built on the conclusions of any or of all the
sciences? All the sciences are abstract; and all modern sciences
are at least partly constructural. Any knowledge built upon ab­
stract and constructural conclusions must necessarily itself be
abstract and constructural. But metaphysics is not an abstract
science, as we have seen abundantly; and it is an ontological
knowledge, a knowledge of the real as it is. Hence, it is simply
impossible for metaphysics to be built upon the conclusions of
any or all sciences. Furthermore, the specialized and interpreted
evidence of the special sciences cannot serve to ground either
philosophy in general or metaphysics in particular. True, the evi­
dence metaphysics seeks can be found in almost any experience
inasmuch as it is a direct experience. But, as scientists are becom­
ing more fully aware, the scientific “fact” is not simply experi­
enced; it is a theoretically interpreted statement of something
experienced. But the theoretical interpretation of any science in­
volves both abstraction and construction and, consequently, is
thereby not suitable as a point of departure for philosophy.
Thirdly, metaphysics cannot be built upon the conclusions of the
philosophy of nature.28 First of all, even the philosophy of nature
is abstract. In particular, it presupposes without discussing the
reality of its object.-9 It knows, accepts, but never mentions exist" Cf. Owens, “A Note on the Approach to Metaphysics,” The New Scho­
lasticism, XXVIII (1954), 454-476.
" It is an axiom commonly admitted by all Aristotelians that “no science
proves the existence of its object—except somehow, metaphysics.”

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277

ence. The being which is the object of the philosophy of nature
is predicamental being. For that reason, it can never serve to
ground the study of the real as real, of that-which-is.so Secondly,
the object of the philosophy of nature (as ordinarily understood)
is intrinsically connected with change;31 metaphysics at its crown­
ing point reaches a being which is immune from change, and so
its knowledge cannot successfully be based on the philosophy of
nature.
Moreover, it is unnecessary to look for a foundation for meta­
physics in any of the specialized sciences. Why seek such a foun­
dation? Most of those who do so, give as a reason that they must
keep metaphysics in touch with reality, as if the only alternative
were to begin with sheer unattached ideas of nothing in particu­
lar. But, in fact, metaphysics is grounded in the immediate experi­
ence of sensible being; it is based directly on reality. It already
has a better foundation of its very nature than could be given it
by any abstract science.
Quite a contrary point of view is taken by those who assert that
all tlie special sciences are based on metaphysics. On the ground
that metaphysics alone can formally treat of tlie most universal
principles of knowledge, they maintain that all the sciences which
use those principles are thereby based on metaphysics. This, how­
ever, is an overstatement. It is true that only metaphysics can
discuss certain universal principles correctly. But that does not
make the other sciences formally depend on metaphysics. Any
particular science starts with a certain number of assumptions,
and, as far as the internal necessities of that science are con­
cerned, these assumptions can remain unproved assumptions. As
long as a thinker works within that particular science, he need
never go back beyond those assumptions. True enough, if the
thinker wants to find the foundation of his science outside that
science and continues his search far enough, he will ultimately
*’Cf. Owens, loc. cit.
” "Nature” according to the Aristotelians is "the first principle of motion
and rest”; therefore, it is material, changeable, and composite.

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come to metaphysics. But this search is precisely no longer within
his science.32
We have thus seen that there is no direct dependence of meta­
physics upon any other scientific knowledge.33 Is there any de­
pendence at all? Can metaphysics be helped by other organized
knowledges? To some extent, yes. Mainly, it is a matter of avoid­
ing error. Avicenna in the ninth century tried to prove that there
could be only ten intelligences because he thought that there
were in fact only nine spheres. When astronomy showed that the
spheres did not exist, later philosophers were no longer tempted
to prove how many intelligences there are. Similarly, the problem
of the primum mobile simply vanished. The positive help given
by science to philosophy is almost nonexistent for metaphysics,
but it is somewhat more important for ethics, and even more for
the philosophy of nature.

105. Metaphysics and the faith

Does revelation need metaphysics? Does the act of faith in a
revelation need metaphysics? Absolutely speaking, no. Revelation
can be accepted and understood on the basis of spontaneous
knowledge alone. The truths necessary for faith, such as the exist­
ence of God, can be known with certitude by spontaneous knowl­
edge, as we have seen. A Faith can be held and carried out in
practice, even to a very high degree of perfection, without any
philosophy (or theology)34 whatsoever. There may be accidental
•This is not meant to deny that there is an order among scientific
knowledges. There is such an order, or “hierarchy”; but this order is not
such that we can deduce one science from another, substitute one for
another, or tell from one science what another must say in detail. On the
other hand, the more universal and abstract knowledges are prior to the
lesser in logical sequence; sometimes the logically posterior sciences borrow
principles from the prior in the form of axioms or postulates (assumptions);
prior sciences can resolve conflicts among posterior ones.
“In the philosophy of nature, we investigate the nature of knowledge,
and this investigation is of great help to metaphysics when the latter studies
the nature of Cod.
** Unless the term theology is used in a purely etymological sense to
mean “any kind of knowledge about God.”

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279

and extrinsic reasons why some individual may need to learn
metaphysics in order to save his soul, just as there may be a rea­
son why some one needs to learn biology or astronomy. But such
necessities are entirely extrinsic to the nature of revelation and
of faith.
Does a Christian culture need metaphysics? Historically speak­
ing, it would seem necessary that such a culture {not any given
individual, as was just said ) somewhere actively possess a meta­
physics. In general, it seems to be a characteristic of the human
mind to want to push into every possible area that can be known.
If some major area of knowledge is left without its proper corre­
sponding scientific knowledge, some other kind of knowledge will
tend to take it over, with unfortunate consequences. This neces­
sity is not because of the faith but because of the natural tend­
encies of the human mind. Similarly, if a culture fails to meet one
of its problems because of some defect, that culture will suffer
the consequences. If a Christian culture lacks medical knowledge,
it may be destroyed by a plague and, ordinarily, will not be saved
by a miracle. So, too, if a Christian culture lacks metaphysics, it
may be upset by some problem of order—frequently an intellec­
tual one—and, ordinarily, this consequence will not be prevented
by a miracle.
Does theology need metaphysics? Here a distinction must be
made. If wc reserve the term theology for some kind of organized
knowledge, theology will be seen to be of two kinds: positive or
humanistic theology and scientific theology. Humanistic theology
of itself does not need metaphysics, although there may be in­
direct necessities because of the culture or because humanism in
general needs metaphysics as an external help, as we saw above.
Scientific theology is the scientific (demonstrative) understand­
ing of a revelation, and such an understanding becomes scientific
through the application of rational, scientific understandings and
methods33 to revealed truth. Hence, scientific theology strictly
** Naturally acquired knowledge seems to enter into theology in several
different ways. (1) Some knowledge is preliminary or preparatory: arche-

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needs metaphysics for its very existence as scientific knowledge?6
On the other hand, does metaphysics need the faith? If we are
speaking of the rational necessities of an organized knowledge,
no. Metaphysics is a natural knowledge; it is constituted by prin­
ciples discovered in experience and is elaborated by natural rea­
soning. Historically speaking, metaphysics has been helped con­
siderably by the faith, and it can be seriously contended that
Thomistic metaphysics would not have taken the form it did with­
out the faith. Nevertheless, Thomistic metaphysics remains a ra­
tional discipline, subject to strictly rational laws and necessities.
Finally, does the thinker who wishes to penetrate deeply and
truly into the nature of being need the faith? Here the answer is
almost an unqualified yes. Certainly it seems impossible for a
young person to make much out of metaphysics unless he has a
rather firm grounding in the Christian tradition and firmly be­
lieves in the existence of a distinct, personal God. Absolutely
speaking, it might be possible for a virtuous and religious person,
who does not accept the Judaeo-Christian revelation through no
fault of his own, to come to something like a Thomistic meta­
physics after years of experience and reflection. But such a limit­
ing case serves, it seems, only to bring out the fact that metaology, linguistics, knowledge of the pertinent languages, and so forth. (2)
Other knowledge supplies factual premises for arguments; for example,
biology may tell us that a certain material substance is a deadly poison, so
the theologian concludes that to administer such a substance is murder.
(3) Some knowledge enters into theology as materially constitutive; thus,
philosophy enters in as determinable to the goal of the theologian and
supplies him with both organizational principles and means of at least a
partial understanding.
* It is a pedagogical question whether metaphysics should be learned
first, and then the theology, or whether the entire understanding of reality
could be taught together as “Christian Wisdom.” The latter way seems
more ideally perfect; tire former is practically advantageous both in regard
to the time needed and in view of the fact that students have to be pre­
pared to live in an unbelieving world and so must be able to answer ob­
jections with naturally valid answers and to give natural arguments. Each
method also has its disadvantages: the total approach is easily turned into a
nominalistic process where the “philosophy” appears at best as mere opinion
and often as mere words; in taking metaphysics (and philosophy, generally)
first, there is some danger of rationalism.

[105-106]

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physics as a discipline is not based on the faith. Basically, the
reason why the thinker who understands Thomistic metaphysics
and, much more, the thinker who brings about advances in meta­
physics ordinarily must also be a Christian is the unity of per­
sonality. One cannot at the same time deliberately attend to the
conclusion that God exists and rationally will to reject Him.
106. Thomism and other philosophies

We have already indicated in various sections of this book—
and presumably the fact is sufficiently well known—that there are
many philosophies, which approach reality in quite different ways
and, at certain points, differ irreconcilably. This is the so-called
"problem of diversity.” What can briefly be said about it?
One approach to philosophy is to choose a reasonably good
guide, on the basis of authority and tradition, and begin tire study
of philosophy. As we get into a philosophy, we will find our guide
offering evidence for what he says, and we have the right and the
duty to consider (a) whether there actually is such evidence;
(b) whether significant contrary evidence has been sufficiently
considered; (c) whether the evidence really supports the con­
clusion, leads to such an insight, and so on. If it does, we can
accept it unconditionally. If we cannot precisely conclude that
these three conditions are fulfilled but also cannot sec that they
are not fulfilled, it is prudent to accept the doctrine conditionally,
that is, until we see that it is otherwise. Once we have worked
through a relatively complete philosophy, we can go ahead to a
deeper study which will also put us into contact with other phi­
losophies. This further study is almost entirely a matter of ac­
quainting ourselves with the history of philosophy in a very
thorough fashion—not merely by way of memorizing dates and
doctrines but with a solid grasp of the problems, methods, and
presuppositions each philosopher has. On this basis we will be
able to make a final decision about the philosophy we hold. This
is a difficult program, and it is ordinarily possible only for those
who intend to specialize in philosophy. Those who cannot com-

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plete such a program will find no adequate philosophical solution
to their problem.87
Another approach to the problem of diversity of philosophies
is through the history of philosophy. One could begin with the
earliest recorded philosophies and follow the history of philoso­
phy to the present day and, on the basis of what he finds, make
up his mind. This is a relatively impractical way to go about
solving the problem; it would entail a lifetime of study before one
knew where he stood in metaphysics.
A popular contemporary approach is to take and accept the
diversity of philosophical positions in connection with each philo­
sophical problem. This way of solving or rather meeting the
problem of diversity is indeed often used, but it is not very philo­
sophical. For a philosophical position cannot be philosophically
understood apart from the evidence, the principles, and the rea­
soning leading to it. Yet the system of seeing what all the impor­
tant philosophers have to say on each point, as that system is
ordinarily carried out, is merely a recounting of the positions,
with a lot of rhetoric thrown in favor of the one the teacher hap­
pens to be (surreptitiously) advocating. The result of such an
eclecticism is not philosophical thinking at all; it might perhaps
lead to what Plato would call "right opinion,” and again it might
not.
107. The constructural knowledge of being

Can there be a constructural philosophy? There have been such
philosophies; there still are. By a constructural philosophy wc
K There are perfectly reasonable nonphilosophical grounds for solving the
problem. For a Christian, there are relatively few difficulties in solving
the problem on the basis of the harmony between his faith and the
philosophy he accepts. For a Catholic, there remains only the problem of
choosing between the various “Scholastic” philosophies. In principle, this
problem is solved philosophically just like the more general problem of
diversity. If he cannot solve his problem philosophically himself, it should
be pointed out that he is really concerned only with philosophical positions, aud tlie positions are sufficiently common that the problem is not
of major importance for him.

[ 106-107 ]

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mean one whose basic principles and concepts are constructural,
although in most cases they also contain some ontological knowl­
edge (which may result in an internal tension in the philosophy
itself). To take a simple case, we need but consider the “being”
of Parmenides. This immobile, simple, all-inclusive form is not a
reality; to some extent it does help us to understand reality in­
directly. But since being as being is directly (ontologically) intel­
ligible to some extent, a constructural philosophy is unnecessary
and to some extent useless. On the other hand, an ontological
knowledge of reality can be helped out at certain points by con­
structs. To give an instance outside of metaphysics: we can un­
derstand certain things better when we deal with habit-groups in
terms of matter and form, although the term “matter” is not used
in its proper sense. In metaphysics itself, we deal with pure in­
telligibilities; this is especially true in the case of the predica­
ments. For example, relation as a form is a construct; in the real
order there is no form of relation, as we have seen. But we can
understand relational reality by means of such a mentally con­
structed form. The use of such constructs does not make the
whole knowledge constructural, since the basic knowledge in
metaphysics is ontological. We can therefore legitimately speak
of “primary constructs’’ (when they are the basic concepts of a
science ) and “secondary constructs” ( when the constructs appear
in auxiliary positions).
In passing, we have referred to “second-level abstractions.”
Ordinarily, when we speak of abstraction, wc indicate a direct
but incomplete way of understanding a tiling. For example, when
we understand Peter as a “man,” our concept man is abstract,
inasmuch as it does not explicitly include Peter’s individuality.
However, we can also abstract the intelligible form of “man” it­
self. Here, we indicate a partial way of understanding what wc
had previously understood. This is an abstraction performed, not
with regard to a thing, but with regard to what wc know about
a thing. Such an abstraction wc have called a “second-level ab­
straction.” For example, we abstract from Peter’s individuality to

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get tlie concept “man”; we abstract from the general subject in­
cluded in “man” to get the concept “humanity.” This kind of
abstraction is in quite common use, and usually people are not
confused by abstract terms of this kind. Sometimes, however,
they arc; the “state,” for example, is a second-level abstraction
that sometimes is mistaken for a reality as such. We have seen
other instances of misunderstanding with regard to the predica­
ments, especially that of relation.
Another type of second-level abstraction that we have already
referred to is tlie “concept of existence as a form.” We know that
the act of existing, although it is the basic and primary act, is
definitely not a form. We can help ourselves to understand esse
better by an analogy with form. But when we go further and
think that esse is a form, then we have developed a full-blown
construct. It is true that we can do certain things with the “form
of existence”; for example, we can say that properly real things
have the form of existence, whereas mental fictions do not possess
such a form. Provided we know what we are doing, such a pro­
ceeding would not be harmful, although it might be somewhat
useless. But if we think that this is indeed what esse really is,
then we are making use of a primary construct and will most
likely soon be in difficulties.
Similarly, in the course of our study of being, we have referred
to various concepts of being. These concepts, inasmuch as they
were supposed to be the primary and basic understanding of thatwhich-is, played the role of primary constructs. The philosophies
based on them are therefore constmctural, and in considering
them, we have rejected them as inadequate.
But we can still raise a legitimate question: “Can there be a
concept of being which would play tlie role of a secondary con­
struct?” Why should we seek such a construct? One good reason
might be that we seek a way of unifying our knowledge of being.
We know, of course, that being is not strictly one but many: there
are many beings, and these distinct beings do not constitute any
one single being. We know, secondly, that there is no one act of

[107]

CORRELATIONS

285

knowledge by which we can know all beings at once, and, con­
sequently, all our direct knowledge of being is analogous, like the
beings which we know. But is this plurality irreducible? Being, in
the real order, can be reduced to one cause: the unity of the uni­
verse is established ultimately by this: that all other beings arc
caused by the one supreme being. Similarly, in the order of
knowledge, the analogy of being has a unity in that we finally
come to know all other beings as beings by participation, whereas
there is only one being by essence. This is as far as direct knowl­
edge can take us.
But if we reflect on all our knowledge of being, we can see a
kind of pattern in the many acts of knowledge by which we know
the beings that are analogically one. In every case, we understand
a being as “that-which-is.” By looking at all these acts of knowl­
edges, we find this in general to be true: “Whenever we under­
stand something as real, we understand it as something-which-is.”
We can now, by a second-level abstraction, express this statement
in a concept which is a definition: being is that which is under­
stood as something-which-is. Because this definition expresses
what we do when we understand a being, it can also be called a
“law” or a “rule.” ** Because it is a second-level abstraction, the
“rule of conception of being” is a construct, not a direct knowl­
edge of any real tiling. Because it is not a primary but a derived
concept and by no means is it the basic concept or judgment on
which metaphysics is built, it is a secondary construct. As it
stands, this “concept of being as a rule of understanding” is abso­
lutely universal and can be used, if we wish, as a point of refer­
ence to give an external unification to our manifold direct knowl­
edge of being.
Moreover, this constructural concept of being has some direct
“Tins may sound Kantian to some, but there is a difference. The
Kantian “rules” (categories) are constitutive of objects as they appear and
so are primary constructs; the "rule of the conception of being” is derived
from objects ontologically constituted by internal principles and already
known directly as beings in the first sense of that term; hence, it is a
secondary construct.

286

CHAPTER XIV

[107-108]

use as a predicate. It may be extremely significant to say, in some
contexts, that “X is a being.” For example, there are some who
hold that the First Principle of reality, though eminently real in
some sense, is nonbeing (Plotinus, Erigena). To say, in the con­
text of an analysis or criticism of such a position, “God is a being,”
means “God can be truly understood by us as something which
is.” In some other contexts, to say, “This is a being” is equivalent
to saying, “This is a fact” or “This is not a fiction.”

108. The analogy of analogy

The Thomistic tradition almost always implies and often says
explicitly that there is only one real analogy. Take the traditional
interpretation that there are three kinds of analogy: according to
intention alone; according to esse alone; according to both esse
and intention. The first is extrinsic analogy or metaphor; the sec­
ond is univocation (although the individuals as they exist are not
one in being but only similar); the third is intrinsic analogy, and
it is the only one with which metaphysics is concerned. This
analogy, most Thomists hold, is in fact the analogy of proper pro­
portionality. The texts where St. Thomas distinguishes different
kinds of analogy are cither ignored or explained away as con­
cerned with merely material differences. We have not followed
this tradition, both because our study of reality has revealed dif­
ferent types of analogy and because the texts of St. Thomas seem
to say that there are quite different types.30
The bases of division of analogy can be of at least two kinds.
First, we can divide analogy on the basis of the relation between
our predication and reality, and then we find extrinsic and intrin­
sic analogies. An extrinsic analogy is a pure multiplicity, which is
considered by the mind in some unified way. An intrinsic analogy
is one which is inherent in the very things themselves that are
” The published textual studies on St. Thomas’s doctrine of analogy have
proceeded from a systematic standpoint (usually that of Cajetan) and so
have failed to present St. Thomas in himself.

[ 107-108 ]

CORRELATIONS

287

known. An extrinsic analogy is made by the mind; an intrinsic
analogy is to some extent found in the real order.
Secondly, analogy can be divided according to its form, that is,
according to the kind or type of relation in the various analogates.
Here the basic division is into two-term, single-relation types,
and the four-term, proportion-of-proportions type. (The analogy
called by St. Thomas the "many-to-one” analogy is simply a com­
bination of several two-term analogies. For instance, the “manyto-one" analogy of health wherein medicine, food, climate, com­
plexion, and so forth, are analogously healthy in relation to
animal health is a complication of the analogy of medicine to ani­
mal health, food to animal health, and so on. Hence, it does not
seem to need separate consideration.)
Two-term analogies are basically of two different kinds: pro­
portion and participation. Analogies of proportion, in general, are
all those analogies in which one of the analogates is more per­
fectly what the other is deficiently. The meaning of the phrase
“more perfectly” will vary as the analogates vary. Tims, in the
act-potency proportion, the act and potency are analogous, in
that the act is what the potency can be, the act is “suited” to the
potency, the potency to the act—for example, the conception
“understanding” used of the power, the habit, the act (like the
Latin intellectus); or “sight,” used of the power, the act, and the
object. Similar to, and based on, this analogy is the analogy ac­
cording to which a possible can be said to be: for a possible can
be said to be inasmuch as there is an essence capable of receiving
an act of existing and a cause for that possible (which cause actu­
ally exists). Another kind of proportion is that between non­
univocal causes and their effects. This proportion can be extrinsic
if the cause is strictly equivocal; it is intrinsic if the cause is
strictly analogous.40 Thus, in the case of health, the food is an
49 The meaning of die pair of terms, “extrinsic” and “intrinsic," is some­
what different in the cases of the different kinds of proportion. Thus, in the
proportion of act and potency (for example, sight as an act and as a

288

CHAPTER XIV

[108]

equivocal cause of animal health; it does not possess as an inher­
ent perfection the special disposition which it helps to bring
about. Yet an equivocal cause is truly a cause; it possesses some
perfection which unhealthy food does not possess, and it is be­
cause of this perfection also that it is denominated healthy. Note
tliat in this second case, the meaning of “proportion” is slightly
different from that of the first type (potcncy-act proportion);
here, it means “apt to produce, yet not the same and not less.”
A third kind of proportion is that between being and the princi­
ples of being, substance and the principles of substance, essence
and the principles of essence. Thus, the whole concrete individual
is that-which-is; inasmuch as essence, for example, is such a prin­
ciple that in union with another principle a being is constituted,
it can, in a secondary and proportional sense, be truly called a
being. A fourth kind of proportion is that whereby a product of
the mind is made similar to something real. Thus, a “being of rea­
son” is made by the mind, and it is conceived after the manner
of real being, although it is not such. Similarly, “predicamental
being" is considered by the mind after the manner of real being,
although what is known in this way is only a principle of being.
These proportions are clearly extrinsic, and the relation between
the two analogates is that the prior one is the model.
The second kind of two-term analogy is the analogy of partici­
pation. In this analogy, one analogate is by essence (or nature)
what the other is by participation. In other words, one analogate
is by identity what the other analogate has. The most fundamen­
tal instance of the analogy of participation is the analogy of being
between God and creature, which, as we have seen, is not the
first analog}' we discover between the two analogates but can be

power), the analogy is an intrinsic analogy, in the sense that the potency
is by its own intrinsic nature a potency to this specific kind of act and no
other. In causal analog)', an intrinsically analogous cause possesses in itself
a higher perfection which is similar to the perfection of the effect: an
extrinsically analogous, or equivocal, cause contains an equivalent but not a
similar perfection.

[ 108 ]

CORRELATIONS

289

known only when God is known to be a subsistent act o£ existing.
In the analogy between God and creature, the analogate which
is by essence what the other is by participation is also the total
efficient cause of the other. The analogy obtains with regard to
being, goodness, truth, beauty, life, intelligence, and the like.
Another kind of analogy of participation can be found where one
analogate is by its essence what another is by participation, with­
out any causal relation between the two. For example, angels arc
intellectual by nature, men, by participation. Here, the analogy is
real and intrinsic, but it is known in a very indirect way. An ex­
trinsic analogy of participation41 is that whereby the predicamen­
tal accident shares in the being of predicamental substance.
The other basic type of analogy is the four-term type, the anal­
og?' of proportionality’. It is to be found first of all between finite
individuals as beings. It is the first analogy we find in experience,
and it supposes an independent knowledge of each of the analo­
gates. Moreover, between two analogates of this analogy there is
no intrinsic order as such. Another instance of proper propor­
tionality' is the series of pairs of intrinsic constituents of finite
being, considered as act and potency. (The traditional instance
of proper proportionality between substance and accident we will
designate as extrinsic, as made by the mind and not found in real­
ity'; as we have seen, this analogy is thought to be real because of
the confusion between predicamental and metaphysical acci­
dent.)
Schematically, we may consider the picture of analogy thus:
“ An analogy of participation is intrinsic when the participant possesses
the participated act as its own (as a creature really possesses its own act of
existing). An analogy of participation is extrinsic when the participant
does not possess the participated act as its own but refers to the act of
that which is by essence—for example, “predicamental accident” extrinsically participates the being of “predicamental substance” ( which is
predicamental being by essence), in the sense that accident includes sub­
stance in its definition (for example, “color” is die quality of a material
thing; “shape" is a quality of the surface of a material thing; and won).

290

*)
(<

CHAPTER XIV

[108-109]

as on the basis of its relation to the real order: ?xtrjns*c
I intrinsic

(6) according to
its form:

two-term
single­
relationship

act-potency
actual-possible
cause-effect
proportion
components of being
“
of essence
“
of substance
model-modeled

and efficiency:
God and creature
being
goodness
participation
truth
beauty
life, intelligence, and
so forth
without efficiency
extrinsic, by modeling
direct, among individuals as beings
four-term: “act-potency correlation” of the princi­
ples of being

109. Thomism and the Thomists

Repeatedly in the footnotes and in the course of this chapter,
reference has been made to interpretations of St. Thomas which
differ from the one presented here. The appeal has been primarily
to experiential evidence; an introductory book is no place to con­
duct an historical and textual argument. It is to be hoped that the
studies cited in this last chapter will supply to some extent this
part of the total demonstration.12
To anyone who already has some knowledge of Thomism be­
fore he reads this book, the position will appear as more or less
of a departure from what he has learned. “More or less”—for in
“ In addition to the studies cited above, in n. 4, 7, 8, 11, and 13, reference
should be made particularly to Etienne Cilson, Being and Some Philoso­
phers, 2d ed. (Toronto, Pontifical Institute of Mediaeval Studies, 1953);
Le Thomisme, 5th ed. (Paris, Vrin, 1945); Réalisme thomiste et critique de
la connaissance (Paris, Téqui, 1939).

[ 108-109 ]

CORRELATIONS

291

fact there are many Thomisms. Some hold that there is a quidditative concept of being, a concept of the act of existing itself, that
judgment is a composition of two concepts, that we have a con­
ceptual knowledge of what God is, that the proper point of de­
parture is the concept of being itself. Others, Thomists too, deny
all this. On another point, that of analogy, there are also several
positions: that there is only one type of analogy; that there are
several types all combined at once in the analogy of being; that
there are several irreducible types of analogy, even of the analogy
of being. There are differences in the interpretation of the cate­
gories and of their relation to real being. There are some Thom­
ists who admit constructural knowledge; others who do not.
There are all sorts of positions on the relation of metaphysics to
experience, to other parts of philosophy, to other disciplines.
In the presence of this historical situation, it seems legitimate
to ask that this book not be judged on the basis of its agreement
or disagreement with any commentator on St. Thomas, no matter
how exalted the historical position of that commentator and no
matter what his merits be in theology or history or in other
branches of philosophy. Does the evidence appealed to square
with experience? Is the understanding of that experience, and the
conclusions drawn from it, in harmony with the actual philosophi­
cal understanding of St. Thomas himself as he has chosen to ex­
press it in the solution of the problems as they came to him in
the context of his own time?
The concern for the authentic understanding of St. Thomas is
not an authoritarian one. It is simply that St. Thomas’s thought
has a directness and a four-square fit with experiential evidence,
a profundit}', and an all-encompassing power that seem to be
unique among philosophers, Christian as well as non-Christian.
If this book can bring forth in the student the ability and the
desire to read St. Tilomas directly, it will have fulfilled its imme­
diate aim. St. Thomas himself will then be the guide that will lead
him to a philosophical understanding of being and, in that, to a
knowledge and love of God.

Index of Passages

From St. Thomas Aquinas
Commentary on the Epistle to the Hebrews, chap. 2, lect. 3 . . 184-185
Commentary on the Epistle to the Romans, chap. 1» lcCt- 6 • • 183-184
Commentary on Aristotle’s Ethics, Bk. I, lect. 7, No. 95 .
62-63
Commentary on Aristotle’s Metaphysics
Proemiuni............................................................................................ 19-21
Bk. I, lect. 2, No. 47
......................................................
22-23
lect. 10, No. 158 ...................................................... 206-207
lect. 11, No. 179 ............................................................ 209
Bk. Ill, lect. 12, No. 501 ............................................................ 208
Bk. IV, lect. 1, Nos. 529-533 ................................................
49-50
lect. 1, Nos. 534-536, 539 ....................................
97-98
ket 1, No. 558 ............................................................ 182
lect. 2, No. 560 ............................................................ 209
Bk. V, lect. 2, Nos. 771, 773, 774-775 .............................. 158-159
lect. 7, Nos. 843-844 ...................................................... 209
lect. 8, No. 879 ............................................................
63
lect. 17, Nos. 1004-1005 ................................................ 254
lect. 20, No. 1063 ................................................ 255-256
Bk. VII, lect. 2, No. 1278 ...................................................... 117-118
lect. 2, Nos. 1287-1289 ........................................... 226-227
lect. 4, Nos. 1352-1853 ........................................... 237-238
lect. 8, Nos. 1440, 1442c, 1412z, 1444-1446 . . 141-142
Bk. VIII, lect. 1, Nos. 1683-1684 ................................................. 227
lect. 1, Nos. 168-S-16S9.......................................................97
Bk. IX, lect. 3, Nos. 1805-1806 ................................................. 117
lects. 7, 8, Nos. 18-16-1847, 1856, 1861
.... 118
Bk. X, lect. 3, Nos. 1979-1980 .......................................... 227-228
lect. 3, No. 1982 ............................................................ 224
Bk. XI, lect. 9, No. 2313 ............................................................ 256
Bk. XU, lect. 1, Nos. 2-119-2420 ................................................ 206
lect. 2, Nos. 2429-2430 ..........................................
73-74
Commentary on Aristotle’s Physics, Bk. Ill, lect. 5 ........................ 225-226
Commentary on Aristotle's Posterior Analytics, Bk. II, lect. 41 . . . 181
Comme»tor{/ on Boethius's De Trinitate, q. 5, art. 3 .
50-51
Commentary on the Books of the Sentences
Prologue, q. 1, art. 2.........................................................................22
q. 1, art. 2, ad 2....................................................142-143
Bk. I, dis. 2, q. 1, art. 1, arg. 4....................................................... 99
dis. 2, q. I, art. 3 ................................................
185, 208
293

294

PASSAGES FROM ST. THOMAS AQUINAS

dis. 3, q. 1, art. 2........................
dis. 8, q. 1, art. 1........................
dis. 8, q. 4, art. 2, ad 1
dis. 8, q. 5, art. 2........................
dis. 19, q. 5, art. 1........................
dis. 20, q. 1, art. 1 .
dis. 26, q. 2, art. 2, ad 2 .
dis. 37, q. 4. art. 3........................
Bk. II, dis. 1, q. 1, art. 1........................
dis. 3, q. 3, art. 2........................
dis. 3, q. 1, art. 3........................
Bk. Ill, dis. 6, q. 2, art. 2........................
dis. 27, q. 2, art. 4, qa. 2 .
Bk. IV, dis. 1, q. 1, art. 4, qa. 1 .
Contra Gentiles, Bk. Ill, chap. 9 .
De. Malo, q. 1, art. 1..........................................
q. 1, art. 1, ad 19..............................
Quodlibet II, art. 3....................................
Ill, art. 20..............................
VII, art. I, ad I....................................
IX. art. 3..........................................
Summa Theologiae, Pt. I, q. 9, art. 1 .
Pt. I, q. 48, art. 2, ad 2 .
Pt. I. q. 88, art. 2 and ad 2
Pt. Ill, q. 2, art. 7, ad 2 .
On the Power of God, q. 7, art. 10, ad 8 .
Truth, q. 2, art. 11..........................................
On the Virtues in General, art. 11 .

.....................................51
................................... 100
................................... 184
................................98-99
................................... 207
................................... 255
........................ 254-255
............................... 74-75
........................ 99-100
........................
21-22
................................... 181
................................... 237
.....................................22
................................... 142
...................................224
........................ 210-211
................................... 224
. . .
181-182, 224
................................... 181
................................... 183
................................... 238
.................................... 74
...................................224
.....................................52
................................... 255
...................................256
..................................... 83
................................... 238

Index of Names and Subjects
Italicized numbers indicate definitions
Absolute nature, 54
136, 137; of being, 57; of emi­
Abstraction, 37-38, 39-40, 41-42, 47,
nence, 135-137, 140, 143, 165,
50-51, 52, 262, 276; formal, 37170, 173; of participation, 17038, 47, 230; second-level, 38, 191,
174, 180, 181-182; of proportion,
249, 284, 285; three degrees of,
63, 79, 83, .93, 98, 107, 114, 137,
39; total, 37, 47, 214, 215
142, 173, 190, 192, 213, 215; of
Accident, 78. 79, 93, 95, 98, 101,
proportionality, 58, 61, 62, 63, 79,
107, 121, 122, 206, 213, 223, 229,
137, 172-173; of substance, 83
236, 237-238, 241; formal, 122; Analysis (philosophical), 162
predicamental, 230, 233, 241; Analytic principle: See Principle, per
proper, 82
se known
Act, 70, 102, 107, 109, 117, 122, Angels, 172
131, 133, 168, 198; first and Anselm, St., 166
second, 113, 124 (see also Exist­ Apprehension, 40, 47, 50, 214
ing, act of); pure, 171, 180; see Aquinas, St. Thomas, 13, 19, 48,
also Being in act
57, 60, 62, 82, 96, 105, 117, 128,
Act-potency correlation, 153, 245
140, 158, 163, 164, 171, 180, 198,
Acting, 122-123, 138, 171; imma­
205, 223, 237, 247, 253, 257, 258,
265, 268, 275, 286, 290-291; see
nent, 125
Action, 125,138, 145, 147, 244, 247also Index of Translated Passages
248, 253, 256; immanent, 92, 152,
from St. Thomas Aquinas
153-154, 158, 250; transient, 138, Aristotle, 13, 15, 19, 73, 94, 140,
247, 265
154, 158
Activity, 92, 105, 148, 260; aimless, Atheism, 161
152; conscious, 144-145; natural, Attribution, 232
Augustine, St., 206
147-150; transient, 92
Avempacé, 52
Actualism, 26-27, 65
Averroës, 26, 32
Adler, Mortimer J., 272
Agent, 119-120, 121, 125, 131, 138, Averroism, 32-33
141, 146, 151, 248; see also Cause, Avicenna, 26, 100, 278
efficient
Beautiful, 203-204
Agnosticism, 162, 174
Becoming, 69, 72, 124; see also
Albertson, James S., 236
Change
Analogous, 61
Being, 35, 41, 47, 48, 49, 54-56, 61Analogue (analogate), 61
62, 65, 73, 89, 99-100, 101, 107,
Analog)’, 63, 78-79, 198, 286-290;
110, 172, 186, 187, 202, 206, 212,
causal (see below Analogy of emi­
219, 222, 231, 237; analogy of, 143
nence); extrinsic, 136, 137; extrin­
(see also Analogy); as being, 44,
sic and intrinsic, 289; intrinsic,
295

296

INDEX

47, 48, 266; community of, 56;
concept of, 57, 188, 284; in act,
70, 72, 102, 133; in common, 21;
in potency, 70, 72, 102, 133;
meanings of, 224; metaphysical
knowledge of, 41-44; of reason,
190-192, 204, 206, 243; predica­
mental, 214, 216, 222, 224, 231,
232-233, 237, 238, 277; primi­
tive notion of, 39-41; sensible,
266; unity of, 187
Boyle, Robert R., 60
Brute, 146
Cajetan, 41, 57, 286
Caldin, E. F. 19, 180
Category. See Predicament
Causality, 121, 123, 125, 134, 138,
170; theorem of, 130-131
Cause, 120,138. 158-159, 245; anal­
ogous, 128, 136-137, 139, 165,
170, 173; efficient, 121, 138, 147,
159 (see also Agent); equivocal,
128, 136-137, 110, 142, 165; ex­
emplar, 130, 139; final, 146, 157
(see also End, Coal, Finality);
first, 127, 139, 164, 166; formal,
121, 138, 159; instrumental, 128129, 139, 142, 165; material, 121,
138, 159; of becoming, 127; of
being, 127; principal, 128-129,
139, 142, 165; secondary, 127,
129-130, 139, 160; univocal, 127128, 135, 139, 142, 163-164
Certitude, 14, 22, 23
Chance, 154, 157, 177, 180; and
finality, 157; kinds of, 156
Change, 64-65, 68-71, 72, 73-74, 97,
102, 119-120, 124, 144, 167, 219
(see also Becoming); accidental,
76-78, 95; substantial, 80-83, 95
Christ, 236
Christian culture, 279
Collins, James, 26
Coming-to-be. See Change
Common sense, 1, 269-273
Compénétration, 85
Composition, 73, 86, 90, 99
Comte, Auguste, 26
Concept, 37, 40, 88; see also Being,
concept of

Condition, active, 119, 137; passive,
119. 137
Construct, 192, 248-249, 283-284
(see also Knowledge, constructural); primary and secondary,
283-284
Contingence, 132-133, 134, 139, 151,
169, 174, 179
Contrary, 74
Cosmogony, 164
Cosmology. See Philosophy of nature
Creation, 174, 176, 201

Defective. 147
Definition, 17, 237-238
De Lubac, Henri, 161
Demonstration, 165, 179
Demonstrative knowledge. See
Knowledge, scientific
Denomination, 218, 225, 230, 256;
extrinsic, 201, 248, 251, 253
Determination, 183
Determinism, 179
Dialectical materialism. See Mate­
rialism, dialectical
Difference, 67-68
Dimension, 85-86
Dionysius, 183
Disposition, 119, 137
Distinction, 66-67, 72; of reason, 67,
72; real, 66-67, 72
Diversity, 281
Doubt, universal (methodic), 267

Effect, 120, 138, 244
Eminence, 183; see also Analogy of
eminence
Empiricism, 65
Empiricists, 5
End, 145, 152,157, 158-159; see also
Goal, Purpose
Entclechy, 117
Epistemology, 8
Equivocal, 53, 59, 61, 62
Erigena, 286
Esse, 123, 182, 213, 216, 232, 237;
accidental, 231, 232, 233; of re­
lation, 243, 255; substantial, 216,
232; see also Existing, act of
Essence, 39, 65, 89, 90, 93, 98-99,
101, 107, 123, 189, 214, 237-238

INDEX

Essen ti alisin 30-33, 47, 65
Eucharist, 236
Evil, 161, 175-176, 199-200, 205,
210-211, 224
Evolution, 156-157
Existence, 193, 284
Existing, act of, 40, 44, 56, 65, 89,
90. 92, .95, 96, 99-100, 101, 106,
107, 109, 122, 151, 160, 175, 198,
233, 238; see also Esse
Experience, 266
Extrinsic denomination, 250

Faith, 10-11, 12, 278, 280
False, 199
Feibleman, James K., 5
Fiction, 189, 191
Fideism, 162
Finality, 147, 157, 177; see also
Cause, final; End; Goal
Finalization, 146, 147, 152-153,157,
244, 245
Form, 97, 101, 107, 130, 150, 198,
213 ( see also Cause, formal ) ; sub­
stantial, 121, 122
Formalization, 212
Foundation of relation, 240, 254;
kinds, 247
Freedom, 171
Generation, 141
Genus, 186
Gilson, Etienne, 13, 19, 26, 48, 62,
96, 158, 180, 186, 223, 290
Goal, 144, 157 (see also Cause,
final; End; Finality); -directedncss, 147-148
God, 21, 90, 99-100, 127, 132, 143,
154, 156, 160, 169, 170, 198, 201,
203, 208, 222, 231, 236, 245, 259,
266-267, 269, 286, 288, 289;
knowledge of, 181, 183-184, 185
Good, 199, 205, 209; proper (un­
qualified), 199-200; transcenden­
tal, 200
“Great books,” 275

Habitus, 251, 253
Harmon, Francis L., 140, 221
Hawkins, D. J. B., 19
Hegel, Georg Wilhelm Friedrich, 57

297

Henle, Robert J., 48, 261
Heraclitus, 64, 70, 71
Hobbes, Thomas, 26
Humanism, 162
Hume, David, 26
Hypostasis, 223
Identity, 66, 72
Immanent acting. See Action
Immaterial, 43; knowledge of, 52
Implicitation, 41, 47
Indefinite reference, 55
Indétermination, 109
Individual, 55, 56, 61, 83-84, 95,
221
Individuality, 86, 94
Individuation, 86, 94, 108
Induction, 261; rational, 262
Influence, 130
Inhere, 232
Insight, 261
Instrument. See Cause, instrumen­
tal
Integral part, 9, 71
Intelligibility, 47, 185, 190, 204, 207,
212, 234, 241, 258; of relation,
243; potential, 258
Intention, first, 217, 241; second,
217, 241
Interference of causes, 155-156, 178

Jesus Christ, 222, 274
Johann, Robert O., 141
Judgment, 40, 47, 50, 88; of implici­
tation (see Implicitation); of sep­
aration (see Separation); percep­
tual, 40
Kane, William H., 260
Kant, Immanuel, 26, 89, 285
Klubertanz, George P., 13, 36, 39,
41, 91, 156, 180, 193, 214, 258,
261, 262, 264, 266
Knowledge, common, 53-54, 62; con­
structural, 261-264; dianoetic, 259;
empiriological, 259; humanistic,
2- 3, 273-276; intuitive, 259; kinds
of, 257-258; manner of, 258;
modes of, 1-7; ontological, 259261; perionetic, 259; scientific,
3- 5, 14-15, 17, 36-37, 53, 276-

298

INDEX

278; spontaneous, 1-2, 7, 36, 163,
265-267; subject of, 4
Kossell, Clifford G., 206, 237, 253

Lauer, J. Quentin, 96
Leibniz, Baron von, 26, 167
Life, 203
Limitation, 133-134, 183
Living thing, 133
Logic, 8, 39

Many, 195
Maritain, Jacques, 19, 48, 73, 96,
117, 161, 180, 206, 258, 259
Marxism 29, 162
Materialism, 26, 27-28, 47, 161-162;
dialectical, 29; modern, 29
Mathematics, 261, 262
Matter, 29, 37, 97, 101, 107, 213,
235; first (see below Matter, pri­
mary); intelligible, 88; primary,
81, 85, 94, 95, 122; see also
Cause, material
Maurer, Armand, 96
Mechanism, 161
Metaphor, 60, 191
Metaphysics, 17, 19-21, 22, 23, 26,
49-50, 51, 160, 189, 264-265, 275276, 278; see also Philosophy of
being
Michotte, Albert, 140
Miracle, 219
Mode, of knowledge. See Knowledge
Motion, 72, 117, 124
Multiplicity, 90, 99
Mysticism, 163

Nature, 93; knowledge of, 260
Necessity, 131-132, 139, 174; kinds
of, 131-132
Negation, 191
Neo-Kantianism, 163
Nominalism, 124
Northrop, F. S. C., 259
Object, 4; formal, 258; of knowledge,
20-21; of knowledge (formal), 5,
17; of knowledge (material),
5, 17; of knowledge (proper), 5,
17; see also Knowledge, object of

Occasion, 120, 138
One, 193-195, 204, 208; kinds of,
194
Operational, 263
Order, potency and act, 115
Organized knowledge. See Knowl­
edge, scientific
Owens, Joseph, 131, 258, 266
Pantheism, 162
Parmenides, 64, 70, 71, 283
Part, 71
Participation, 172, 196, 201, 231232; see also Analogy of participa­
tion
Passage from potency to act, 131,
133, 168
Passion, 124, 138. 244, 248, 253, 256
Patient, 120, 121, 138, 141, 249
Perception, 266; see also Judgment,
perceptual
Per se known principles. See Prin­
ciple, per se known
Person, 221, 223
Personality, 222, 223
Phelan, Gerald B., 62
Phenomenalism, 26
Phenomenological, 261
Phenomenology, 261
Philosophy, 9, 12, 18; constructura!,
282-286; history of, 282; impor­
tance of, 6; of being, 5, 6; of be­
ing (see Metaphysics); of nature,
8, 90, 260, 276-277
Pius XII, 180
Plato, 206, 282
Platonism, 30-31, 52
Plotinus, 286
Plurality, 285
Position (philosophical), 268
Positivism, 162, 174
Positivists, 5
Possibility, 104
Possible, 188-190, 204
Potency, 70, 102, 103, 122, 123,
131, 133, 152, 168-169 (see also
Being in potency); passive, 124
Potency-act correlation, 153, 213,
245
Power, 91, 106, 109, 123, 126, 152;
active, 113

INDEX

Pragmatism, 162-163
Predetermination, 157
Predicable, 217, 223
Predicament, 212, 222, 224-226;
division of, 217-218; see also
Being, predicamental
Presupposition, 266
Principle, 18, 72, 78, 79, 82, 89, 91,
107, 121, 149, 213; of causality,
130; of contradiction, 45; of in­
telligibility, 197; of knowledge, 18,
267; of knowledge (first), 44-46;
per se known, 46, 51, 133
Priority, 89, 117-118
Privation, 74, 98, 191, 200, 206, 210,
224
Proof, 165-168, 179; kinds of, 166
Proportionality, analogy of. See
Analogy
Proportionality, univocal, 60
Purpose, 145, 152, 157
Qualitv, 108, 235-236, 236, 247
Quantity, 86, 234-235, 236
Quiddity, 39, 91, 99, 189

Ratio. See Intelligibility
Real, 24-25, 34-35, 42, 46, 47-48, 64,
188
Realism, 84
Reality, 44
Reduction, 161
Régis, Louis-M., 272
Relation, 126, 239, 244-247, 252;
kinds, 246-247; of reason, 191,
252,- predicamental, 239, 242-243,
252; predicamental (of reason),
240; predicamental (real), 240;
real, 252, 253; transcendental, 239,
252
Religion, 10
Result, 148
Revelation, 278
Russell, Bertrand, 134
Salmon, Elizabeth G., 266
Sartre, Jean Paul, 57
Science, 3,17, 29, 192, 276-278
Scotism, 26, 31-32
Self-evident, 133; see also Principle,
per se known

299

Semantics, 162
Sentimentalism, 162
Separability, 66
Separated soul, 87
Separated substance, 88
Separation, 42-43, 47, 48, 50-51, 52;
from matter, 21; judgment of, 89
Series, 169, 179
Sertillanges, A. D., 117, 158, 181
Sheldon, Wilmon H., 49
Simon, Yves, 271
Simple, 194, 204
Situs, 251, 253
Smith, Gerard, 49
Something, 35, 188, 204
Space, 250
Species, 67
Spinoza, Baruch, 26
Spiritual, 176, 219-220, 251, 258
Statistical law, 157
Subject, of knowledge, 258; of re­
lation, 240, 255-256
Subsistent, 221
Substance, 37, 77, 79, 83, 93, 95,
97-98, 101, 107, 121, 122, 184,
186, 206, 212, 213, 214, 223, 225,
227-228, 229, 235, 237-238, 247;
first, 220, 223; predicamental, 215,
218-219, 231; second, 215, 220,
223
Substantial form, 81, 85, 94; see
also Form; Cause; Formal
Succession, 74
Supposit, 220-221, 223
Surrogate, 263
Tendency, 92, 116, 124, 148, 151,
152, 200, 202, 245, 246
Term of relation, 240
Testimony, 165
That-which-is, 94, 96, 107; see also
Essence
Theism, 161
Theology, 12, 21, 278, 279; natural,
8-9, 160
Theorem of act and potency, 103112
Theorem of causality. See Causality
Thing, 18, 188, 204; material, 18;
principle, 213 (see also Essence);
sensible, 18

300

INDEX

Thomism, 232, 265, 270, 281-282,
286, 290-291
Thomistic philosophy, 15-16, 34-35
Time, 207, 251
Transcendental, 172, 186, 204
Transient action. See Action
True, 195
Truth, 205; kinds of, 195
Understanding, 259
Unique, 194
Universal, 38, 54, 62, 84, 108, 215;
formal (reflex), 54
Universal (simple, direct). See Ab­
solute nature
Universality, 14, 23
Univocal, 47, 53-54, 59, 61, 62, 174175, 187, 262

Univocation. See Univocal

Van Rict, Georges, 271
Van Roo, William A., 96, 117
Verification, 264
Violence, 116
Virtual. 113
Virtually, 40
Walton, William M., 96
When, 250-251, 253
Where, 250, 253
Whole, 194, 205
Wild, John, 19, 49, 73, 117,141, 26)
Wisdom, 20, 280

Ziegelmeier, Edmund H., 269