The Thomist 84 (2020): 339-93

THE LAW OF NATIONS AS DEVELOPING MORAL LAW:
TWO INTERPRETATIONS OF IUS GENTIUM IN THE
THOMISTIC TRADITION
BARRETT H. TURNER
Mount St. Mary’s University
Emmitsburg, Maryland

Il n’y a pas de notion plus épineuse pour un philosophe ou un juriste que la
notion de droit de gens.
Jacques Maritain, La loi naturelle ou loi non écrite (1950)

S

INCE THE Second Vatican Council, Catholic moral
theology has increasingly wrestled with the question of
development in the Church’s moral and social doctrine. For
example, scholars continue to dispute the nature, limits, and
causes of the change in the Church’s teaching on religious liberty
and the death penalty. Yet discovering an adequate way of
describing the development of moral doctrine has been difficult
going. John T. Noonan, Jr., in his well-known explorations of
change in Catholic moral doctrine, could find no more of a
principled rationale for doctrinal developments such as those on
usury, slavery, and religious liberty than the twofold love
commandment of Christ, empathy, and experience.1 According
to Noonan, not even human nature or the natural law limits how
Church teaching can develop, for our knowledge of human
nature is historically conditioned and changes.2 With respect to
1

John T. Noonan, Jr., “Development in Moral Doctrine,” Theological Studies 54
(1993): 676; idem, A Church That Can and Cannot Change: The Development of Catholic
Moral Teaching (Notre Dame, Ind.: University of Notre Dame Press, 2005), 222. See also
idem., “Experience and the Development of Moral Doctrine,” CTSA Proceedings 54
(1999): 43-56.
2
Noonan, A Church That Can and Cannot Change, 213.
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the specific development of the Church’s teaching on religious
liberty as promulgated by Dignitatis Humanae, Noonan could
only arrive at the bare conclusion that the Magisterium is capable
of the “flat rejection of propositions once taught.”3 In his response to Noonan, Avery Dulles argued that the development on
religious liberty can be made intelligible by noting how changing
social conditions call forth new applications of unchanging
teaching, permitting the theologian to see “that there has been
true progress without reversal, even on the plane of propositional
declarations.”4 While Dulles offered an important response to
Noonan in noting how new conditions could change what the
moral law demands, he did not offer a theory of the development
of moral doctrine.
As St. John Paul II suggested in two encyclicals, any Catholic
theory of the development of moral or social doctrine should
attend to the changing relationship between the principles of
moral theology and the changing conditions of human life. In
Sollicitudo Rei Socialis (1987) he wrote that the Church’s
“teaching in the social sphere” is both “constant” in regard to its
“fundamental inspiration” and “ever new” on account of “necessary and opportune adaptations suggested by the changes in
historical conditions and the unceasing flow of the events which
are the setting of the life of people and society” (SRS 3). This is
the case not merely within nations but also in regard to “the
configuration of the world,” which “has undergone notable
3

Ibid., 157: “The promulgation of Dignitatis [humanae] personae was a triumph of
development. It showed that the development could mean the flat rejection of
propositions once taught by the ordinary magisterium.”
4
Avery Dulles, S.J., “Review of A Church That Can and Cannot Change: The
Development of Catholic Moral Teaching,” First Things, October 2005; also idem,
“Dignitatis Humanae and the Development of Catholic Doctrine,” in Catholicism and
Religious Freedom: Contemporary Reflections on Vatican II’s Declaration on Religious
Liberty, ed. Kenneth L. Grasso and Robert P. Hunt (Lanham, Md.: Rowman and
Littlefield, 2006): 61: “The most satisfactory position, I believe, is . . . that there has been
true progress without reversal, even on the plane of propositional declarations.” See also
Avery Dulles, S.J., “John Paul II on Religious Freedom: Themes from Vatican II,” The
Thomist 65 (2001): 161-78; idem, “Continuity and Change in Catholic Social Teaching,”
Journal of Law, Philosophy and Culture 2 (2008): 73-88.

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changes and presents some totally new aspects” (SRS 4). He
similarly stated in Veritatis Splendor (1993) that while human
nature is “the measure of culture” and that “some things do not
change and are ultimately founded upon Christ,” nonetheless the
application of the unchanging core of Catholic moral teaching
occurs “in the light of different cultural contexts” and “in the
light of historical circumstances” (VS 53). A Catholic theology of
the development of moral doctrine therefore must attend to the
interplay between on the one hand the Church’s authoritative
exposition of the unchanging deposit of faith and the natural law,
and on the other hand the changing conditions of human life.
Without giving a full treatment of a theory of the development
of moral doctrine or of any particular case of it in detail, this
article only offers a grounding for such a theory in the recovery
of a concept from the Thomist tradition that relates the unchanging natural law to changing social conditions. This concept
is the “law of nations” (ius gentium). Such a concept will be useful
for later proposing a full treatment of development in moral
doctrine in general, and specific doctrinal changes in particular.
In fact, the law of nations has already begun to be used to explain
doctrinal developments in religious liberty and the death
penalty.5 Yet the precise meaning of ius gentium in the Thomist
tradition is itself a matter of debate.
According to this debate, the law of nations is either a
universal body of customary law that assists in keeping the
natural law, or simply the conditional conclusions of natural-law
principles arrived at under new social and political conditions.
This debate suggests that the Thomistic tradition has resources
for discussing not only the development of the natural law in
society, but also for discussing how Catholic social doctrine itself
5

Basile Valuet, O.S.B., La liberté religieuse et la tradition catholique: Un cas de
développement doctrinal homogène dans le magistère authentique, 3d ed., 6 vols. (Le
Barroux, France: Éditions Sainte-Madeleine, 2011), esp. 2:768-94; Barrett H. Turner,
“Dignitatis Humanae and the Development of Moral Doctrine: Assessing Change in
Catholic Social Teaching on Religious Liberty,” (Ph.D. diss., The Catholic University of
America, 2015); Barrett H. Turner, “Pope Francis and the Death Penalty: A Conditional
Advance of Justice in the Law of Nations.” Nova et vetera (Eng. ed.) 16 (2018): 1041-50.

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develops. The various figures and lines in the debate affirm the
immutability of the natural law in itself while they also affirm a
socio-historical, conditional element of justice that is added to
the natural law even on a universal scale. Two lines in the debate
have sought to clarify precisely in what sense the law of nations
is distinct from the natural law and in what ways it can change,
building upon St. Thomas Aquinas’s fundamentally ambiguous
account of the law of nations. The first line arose among
Dominican theologians who employed Thomas’s theology of law
in response to Spanish claims in the New World, led by Francisco
de Vitoria (d. 1546). I will call this the Salamancan line. Among
its adherents were Domingo de Soto (d. 1560), Melchior Cano
(d. 1560), Domingo Báñez (d. 1604), Francisco Suárez (d. 1617),
and Charles-René Billuart (d. 1757). The second line emerged
from the more recent attempt to reconcile Catholicism to liberal
democracy and subjective human rights in the Neo-Thomist
revival, led by Jacques Maritain (d. 1973). I will call this the NeoThomist line. Adherents included Yves Simon (d. 1961), MarieMichel Labourdette (d. 1990), Benoît-Dominique de la Soujeole,
and John Finnis.
Of these two lines, the Salamancan is better able to account
for change in the law of nations without falling into historicist or
relativist interpretations of the natural law or the ordinary exercise of the Magisterium in moral doctrine. Maritain’s position,
on the other hand, is liable to present a theory of doctrinal development that never quite explains how our current knowledge
of the natural law should always constitute a permanent advance
in the truth. However, the modifications that Labourdette made
to the Neo-Thomist line offer a powerful model for understanding development in moral doctrine, thanks to his attention
to the conditional nature of some demands of the natural law.
This article first locates the origins of the two divergent
interpretations of the law of nations within the Thomist tradition
in the ambiguity with which Thomas discusses whether the ius
gentium is natural or positive law. The second and third sections
respectively delineate the essential features of each of these
distinct approaches to interpreting Thomas. The Salamancan,

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which was the common opinion of Thomists until the twentieth
century, holds that the law of nations is essentially universally
binding custom added to the natural law, and hence positive in
content. The law of nations is only morally necessary for keeping
the natural law and is therefore mutable depending on conditions. The Neo-Thomist line, which became ascendant in
Thomism under the influence of Maritain, holds that the law of
nations is a set of strict conclusions from natural-law principles
and thus belongs essentially to the natural law. These conclusions
are known more perfectly under or extended more concretely
within progressive civilizational conditions. A fourth section
evaluates what these two lines of interpretation can contribute to
a Thomistic theory of the development of the moral law, and
consequently to a Catholic theology of the development of moral
doctrine.
I. SAINT THOMAS’S AMBIGUOUS DOCTRINE OF
THE LAW OF NATIONS
Thomas’s treatment of ius gentium is ambiguous insofar as it
is unclear whether he holds that the law of nations is essentially
of the natural law, or whether it is a set of institutions and
customs added to the natural law by human agreement. In texts
treating of the law of nations in itself, he teaches the former,
while in texts treating of institutions that are part of the law of
nations, he says the latter. This ambiguity stems from his choice
of authorities in the unusual and late texts in which he distinguishes the law of nations from natural and positive law. In
the Treatise on Law (STh I-II, q. 95) he draws upon St. Isidore of
Seville to identify the law of nations as a body of human positive
law deduced as conclusions from natural-law principles. In the
Treatise on Justice (STh II-II, q. 57), however, Thomas attempts
to reconcile the Roman jurist Ulpian with his own account of
natural law as particular to the rational animal. Ulpian claimed
that all animals follow the ius naturale and that only humans
follow the ius gentium. The law of nations would then be specific

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to humans as such, not a body of positive law derived from
natural law.6
As noted by historians, Thomas paid much more deference to
the formulas of the Roman jurists concerning ius naturale and ius
gentium than did his predecessors and his teacher, St. Albert, who
eschewed the jurists’ categorizations.7 Not only do the jurists
appear to disagree with one another about the precise contours
of the law of nature and the law of nations, but it is also unclear
in what way their formulae could be compatible with the account
of natural law laid down by Albert and Thomas as proper to man,
the rational animal. Ulpian, for example, asserted that “natural
law is what nature teaches all animals” (ius naturale est quod
natura omnia animalia docuit) and that the “law of nations is
what human nations use” (ius gentium est quo gentes humanae
utuntur).8 The jurist Gaius, however, simply identified the law of
nations and the natural law: “what natural reason establishes
among all men and which is kept equally among all, is called the
law of nations, for nearly all nations practice this law.”9 That the
Roman jurists did not consistently distinguish natural law and the
law of nations compounds the difficulty of Thomas’s eventual
attempt to harmonize them with Isidore’s teaching.10
6
The relevant texts fall late in Thomas’s career, during his second Parisian teaching
period, no earlier than 1269 and no later than 1272. Dates from Jean-Pierre Torrell, O.P.,
Initiation à saint Thomas d’Aquin: Sa personne et son œuvre, 2d ed. (Fribourg: Éditions
Universitaires, 2002), chap. 11. The phrase “law of nations” (ius gentium) occurs in St.
Thomas’s work at Quodl. II, q. 4, a. 2; I Polit., lect. 4; V Ethic., lect. 12; and STh I-II,
q. 95, a. 4; II-II, q. 12, a. 2; and q. 57, a. 3.
7
Odon Lottin, O.S.B., Le droit naturel chez saint Thomas d’Aquin et ses prédécesseurs,
2d ed. (Bruges: Charles Beyaert, 1931); Jean-Marie Aubert, Le droit romain dans l’œuvre
de saint Thomas (Paris: J. Vrin, 1955), 91-122; Michael Bertram Crowe, “St. Thomas and
Ulpian’s Natural Law,” in St. Thomas Aquinas, 1274-1974: Commemorative Studies, ed.
Armand A. Maurer et al. (Toronto: Pontifical Institute of Mediaeval Studies, 1974),
261-82.
8
Ulpian is cited in Justinian, Digest 1.1.1.3. Unless otherwise indicated, all translations
in this article are my own.
9
Ibid. 1.1.9: “quod vero naturalis ratio inter omnes homines constituit, id apud omnes
peraeque custoditur; vocaturque ius gentium, quasi quo iure omnes gentes utuntur.”
10
In addition to the historians noted above, see the opinion of Alexander Passerin
d’Entrèves on how the disparate formulae of the Jurists cohere in Roman law (Natural

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Perched ambiguously between natural and positive law,
Thomas’s ius gentium seems to be a subset of the natural law,
either as conclusions from natural-law precepts which are discovered by reason and repromulgated in human positive law (STh
I-II, q. 95, a. 4), or as that part of the natural law which concerns
what is naturally right for the human creature (inclination to
society), abstracting from inclinations common to lower beings
(inclination to procreation [V Ethic., lect. 12; STh II-II, q. 57, a.
3]). The ambiguity in Thomas’s teaching concerns whether the
law of nations is essentially and strictly of the natural law, or a
law enacted or instituted by human decision that assists in keeping the natural law but is not strictly demanded by it. Though at
times Thomas seems to hold that ius gentium is simply natural
law (though this is disputed by various commentators), he
complicates a simple identification by teaching that private
property is an institution of the law of nations and as such is
added to natural law by human agreement. But something cannot
be both natural law and added to natural law, at least not in the
same sense.
Our issue here is not whether the natural law is the same for
all men, or its mutability (STh I-II, q. 94, aa. 4-5). For Thomas,
the law of nations is not the “change” in the natural law that
happens when the application of the general, common principles
of the natural law fails to generate the secondary precepts which
are right for most cases. In other words, we are not dealing here
with the few cases in which the secondary precepts fail in regard
to rectitude on account of “some particular impediment” (e.g.,
returning a deposit to a madman or conspirator). The law of
nations does not pertain to such cases, for it pertains to the usage
of the peoples in general.
Indeed, the problem for Thomas is distinguishing the law of
nations from the natural law itself. In question 95, article 4 of the
Prima secundae, he has to account for Isidore’s division between
the natural law, the law of nations, and civil law, which categories
Law: An Introduction to Legal Philosophy [New Brunswick, N.J.: Transaction, 1994],
27-34).

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Isidore inherits from the Roman jurists. Since Isidore speaks of
both ius naturale and ius gentium as common to all people (obj.
1), Thomas must provide a way of distinguishing what appear to
be identical categories.11 He has already divided human positive
law according to the two ways in which it is derived from the
natural law (STh I-II, q. 95, a. 2). In the mode of “conclusion”
(conclusio), a legislator promulgates a law that can be deductively
drawn from the principles of the natural law, similar to the way
conclusions in theoretical disciplines are drawn from first principles. Thomas’s example is that murder is contrary to human as
well as to natural law, non esse occidendum being deducible from
nulli esse malum faciendum. In the mode of “specification”
(determinatio), by contrast, the legislator has to establish a
determinate ordinance in order to fulfill the natural law’s general
requirement to live harmoniously in society. This mode is like a
builder’s moving from the general form of a house to its specific
details—a house of such-and-such dimensions, rooms, and floors.
Thomas’s example is that the punishment for a crime would be
such and such, which derives from the general obligation of civil
power to punish injustice.12 Importantly, the force of a determinatio comes entirely from its human promulgation, whereas a
conclusio gets “something of its strength from the natural law”
(ibid.). Both modes of derivation yield “human positive law,” but
11
All Latin quotations of St. Thomas are taken from the Leonine edition (Sancti
Thomae Aquinatis doctoris angelici Opera omnia iussu Leonis XIII. P. M. eddita, cura et
studio fratrum praedicatorum [Rome: Leonine, 1882-]), cited by volume and page
number, unless otherwise noted. STh I-II, q. 95, a. 4, obj. 1: “Comprehended under
[positive] law is the law of nations, which, as Isidore says, is thus so named because ‘it is
used by nearly all nations.’ But just as he himself says, ‘natural law is common to all
nations.’ Therefore the law of nations is not contained under positive law, but rather
under natural law” (“Sub hoc enim iure comprehendit ius gentium, quod ideo sic
nominatur, ut ipse [Isidorus] dicit, quia eo omnes fere gentes utuntur. Sed sicut ipse dicit,
ius naturale est quod est commune omnium nationum. Ergo ius gentium non continetur
sub iure positivo, sed magis sub iure naturali” [Leonine ed., 7:177]). Thomas refers to
Isidore’s Etymol. 5.6 and 5.4, respectively.
12
Cf. V Ethic., lect. 12. For further discussion on the derivation of positive from
natural law, see John Finnis, Natural Law and Natural Rights (Oxford: Oxford University
Press, 1980), 281-90.

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are “positive” (posita) in different senses: the deduction is a kind
of human repromulgation or clarification of the natural law’s
ineluctable and specific demands, while the specification is more
of a creative act of the legislator finding a fitting way of achieving
what the natural law demands only in a general way; the
specification is therefore “positive” in a way that the deduction
is not.13 Both are promulgated by human law and are positive in
that sense.
Thomas collates these two modes of derivation with Isidore’s
law of nations and civil law in article 4 of question 95, seeming
to identify the law of nations with the first mode, that of
deductions (conclusiones) from natural law. He writes:
To the law of nations pertain those things that derive from the law of nature as
deductions [conclusiones] from principles, such as just purchases, sales, and
other things like that. Without those things humans are not able to live together,
which is from the law of nature, since man is naturally a social animal. . . . Those
things, however, which are derived from the law of nature in the manner of the
specification of a particular [particularis determinationis] pertain to civil law,
according to what any city determines is suitable for itself.14

On this interpretation, Isidore’s ius gentium would be a body of
deductions from the natural law universally necessary for life in
society, while the ius civile would consist in the specifications of
particular cities. Yet where article 2 gave the more evident
conclusion of murder as an example of a conclusio, Thomas in
article 4 gives the examples of “just purchases, sales, etc.,”

13

For the two senses of positivity in Thomas’s treatment of human law see James
Bernard Murphy, The Philosophy of Positive Law: Foundations of Jurisprudence (New
Haven: Yale University Press, 2005), chap. 2; and Aubert, Le droit romain dans l’œuvre
de saint Thomas, 105-8, 122.
14
STh I-II, q. 95, a. 4: “Nam ad ius gentium pertinent ea quae derivantur ex lege
naturae sicut conclusiones ex principiis, ut iustae emptiones, venditiones, et alia
huiusmodi, sine quibus homines ad invicem convivere non possent; quod est de lege
naturae, quia homo est naturaliter animal sociale, ut probatur in I Polit. Quae vero
derivantur a lege naturae per modum particularis determinationis, pertinent ad ius civile,
secundum quod quaelibet civitas aliquid sibi accommodum determinat” (Leonine ed.,
7:178).

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examples given in Justinian’s Institutes15 as institutions contained
in the law of nations. These are less evidently connected with the
natural law, however, at least in a strict sense. Thomas does not
specify whether he means that there is a general need for laws
about buying and selling, or whether he is referring to specific
laws about types of contracts or more minute regulations of just
exchange. In any case, the law of nations here is a body of positive
law—such as civil laws prohibiting homicide—that as necessary
conclusions stem from the natural law’s content. It is possible that
Thomas means that the law of nations includes both strictly
necessary deductions from the natural law (the prohibition of
homicide) and deductions that are less strictly necessary
(institutions pertaining to property), in contrast with civil law as
such, which is comprised of the specifications unique to this or
that civil code, not including laws found in the law of nations.
In reply to the first objection, that natural law and the law of
nations would then be identical, Thomas utilizes Ulpian to make
a further distinction. Since deducing “things not very remote
from their principles” is a specifically human activity qua
rational, the law of nations is “in a certain mode natural to man”
and not to other animals. That the law of nations is universal like
the law of nature is no difficulty, for “in such matters humans
easily consent.” Yet the act of deducing by human reason itself
distinguishes the law of nations “from the natural law [a lege
naturali], above all from that which is common to all animals.”16
In light of Thomas’s definition of natural law properly understood as the rational creature’s participation in the eternal law,
thereby excluding brute animals from governance by natural law
(STh I-II, q. 91, a. 2, ad 3), his reference to natural law as being
common to all animals displays unusual deference to Ulpian.
Ulpian designates ius naturale as the “animal” or body-dependent
norms for human behavior, such as the liceity of male-female
coupling. At least, the comment is strange if lex naturalis and ius

15
16

Justinian, Institutes 1.2.2.
STh I-II, q. 95, a. 4, ad 1.

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naturale are synonyms, which is a point of disagreement between
the two interpretive lines discussed below.
When Thomas discusses the derivation of positive law from
natural law in his commentary on Aristotle’s Nicomachean Ethics
(V Ethic., lect. 12), he appears to diverge from what he said
previously about the necessary relation of the law of nations to
the natural law. He states that “in such manner,” that is, the
manner of a deduction being drawn from principles (sicut
conclusio ex principiis), “positive or legal law [iustum positivum
vel legale] cannot arise from natural law [a iuri naturali].”17 Did
not he previously say that human positive law in the mode of
deduction is derived from natural law? Here the contradiction is
only apparent, for in the Treatise on Law Thomas speaks of lex
posita being derived from lex naturalis, whereas in the
Commentary he speaks of iustum/ius positivum and iustum/ius
naturale. Positive law in the first sense (lex posita), at least as far
as the mode of conclusio goes, has some of its strength from
natural law and some from the fact of its human institution. In
other words, it is natural in content but positive in promulgation:
murder is evil of itself, yet a law proscribing it is positive insofar
as a human legislator has written that law. On the other hand, ius
positivum is positive in content as well as in promulgation, and
so is susceptible to variation among political communities:
“natural justice [iustum naturale] exists always and everywhere
[but] this is not applicable to legal or positive justice [iusto legali
vel positivo].”18 It is reasonable to suppose that here Thomas
confines ius positivum to positive law in the more limited mode
of specification (determinatio). This would explain why Thomas
17
“Uno modo sicut conclusio ex principiis; et sic ius positivum vel legale non potest
oriri a iure naturali; praemissis enim existentibus, necesse est conclusionem esse”
(V Ethic., lect. 12 [Leonine ed., 47:305]). My translation is a modified version of St.
Thomas Aquinas, Commentary on Aristotle’s Nicomachean Ethics, trans. C. I. Litzinger
(Notre Dame, Ind.: Dumb Ox, 1993), 325-26. Although this is a commentary, Thomas
brings in the notion of derivation from the principles of the natural law from STh I-II,
q. 95, a. 2.
18
“sed cum iustum naturale sit semper et ubique, ut dictum est, hoc non competit iusto
legali vel positivo” (V Ethic., lect. 12 [Leonine ed., 47:305]).

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includes what “the jurists call the law of nations [ius gentium]”
under Aristotle’s category of “natural justice” (iustitia naturalis),
since according to the jurists the law of nations is “the law which
follows the inclination proper to the nature of man, insofar as
man is a rational animal.”19 This law includes what “all people
are accustomed to follow,” such as the keeping of pacts and the
inviolability of ambassadors. Thomas includes with the law of
nations under natural justice what the jurists call “natural right,”
“which follows the inclination of nature common to man and
other animals, as the union of male and female, the education of
offspring, and so forth,” paraphrasing Ulpian.
In question 57 of the Secunda secundae, Thomas again employs the formulas of the Roman jurists to distinguish further ius
gentium and ius naturale. In article 2, he distinguishes natural law
(ius naturale) and positive law (ius positivum) on the basis of
whether a work is adequate to another man, in two different
senses: ius naturale is drawn from the very nature of the commensuration (ex ipsa natura rei), as “when someone gives so much so
as to receive just as much”; ius positivum is drawn from human
agreement (ex condicto, sive ex communi placito), as “when
someone is satisfied if he receives so much.” Next, in article 3,
Thomas further distinguishes two ways in which something
pertains to natural law (ius naturale). As previously (in STh I-II,
q. 95, a. 4), he must do so in order to answer the question of
whether ius gentium just is ius naturale—a natural question, given
that some make ius gentium a type of human law (Isidore) while
others identify it with natural law (Gaius). The first way in which
something pertains to ius naturale is “according to an absolute
consideration of the matter, as the male from his own conception
has a commensuration to the female for generating from her, and
a parent to a son for nourishing him.” The second way is “accor-

19

“Illud autem ius, quod consequitur propriam inclinationem naturae humanae,
inquantum scilicet homo est rationale animal, [Iuristae] vocant ius gentium, quia eo omnes
gentes utuntur, sicut quod pacta sint servanda, quod legati etiam apud hostes sint tuti, et
alia huiusmodi” (ibid.). On this point, see Aubert, Le droit romain dans l’œuvre de saint
Thomas, 113-14.

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ding to something that results from it, namely, personal property
[proprietas possessionum].” Personal property is not naturally just
in the absolute sense, since “if a field is considered absolutely,
there is no reason why it should belong to this person rather than
that one.” Only when the field “is considered with respect to the
advantageousness of cultivating it and using it peacefully” does a
reason emerge for it to belong to one and not another. Thomas
notes that animals generically can grasp whether something is
naturally commensurate to another in the absolute sense, but only
humans can grasp what is naturally commensurate to another in
the second sense, which is “proper to reason.” To conclude his
argument, he harmonizes Isidore’s distinction of ius naturale and
ius gentium (cited in the sed contra and already discussed above)
with Gaius’s identification of them: “what natural reason
establishes among all men is kept among all nations and is called
the law of nations.”20 In theory, anyway, Thomas situates the law
of nations (ius gentium) within natural law (ius naturale)
according to the specifically human mode of grasping what is
naturally commensurate to another beyond the common animal
mode. Again, he describes the ius gentium either as that part of
natural law repromulgated in human positive law (conclusions)
or that part of the natural law whose precepts pertain particularly
to man qua rational (ius gentium vs. ius naturale).
Whatever Thomas means by defining ius gentium as
specifically human natural law, his discussion of particular
institutions of the law of nations gives it a decidedly positive
content. There is a good example in the case of property, which
Thomas identifies as pertaining to ius gentium. On the one hand,
he says that “natural reason institutes” the law of nations (STh IIII, q. 57, a. 3, ad 3) and that its proximity to natural law as a set
of conclusions is why men “easily consent to it” (STh I-II, q. 95,
a. 4, ad 1). On the other hand, he specifies that the division of

20

“Et ideo hoc quidem est naturale homini secundum rationem naturalem, quae hoc
dictat. Et ideo dicit Gaius iurisconsultus, quod naturalis ratio inter omnes homines
constituit, id apud omnes gentes custoditur, vocaturque ius gentium” (STh II-II, q. 57, a. 3
[Leonine ed., 9:6]).

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possessions is “according to human arrangement” (secundum
humanum condictum), accordingly is “just because posited”
(iustum posivitum), and is therefore an addition to the natural
law (STh II-II, q. 66, a. 2, ad 1). He is more explicit in Quodlibet
II (q. 4, a. 2), where he assigns parental rights to ius naturale and
property rights to ius gentium vel civili.21 In a corresponding
article (STh II-II, q. 10, a. 12), he assigns property rights only to
ius civili, indicating that his doctrine of private property is
positive in content as well as in promulgation.22 He says that the
division of possessions, as well as servitude, “are induced not by
nature but through the reasoning of men with respect to their
usefulness for human life. In this way the law of nature has not
been changed except by addition” (STh I-II, q. 94, a. 5, ad 3).23
Property has a kind of “necessity” for human life in order to
avoid discord and ensure diligent work (STh I, q. 98, a. 1, ad 3;
II-II, q. 66, a. 2).24
Due to his deference to the formulae of various authorities,
Thomas names the law of nations as a kind of deduction from the
natural law, yet acknowledges that it is comprised of positive
institutions deriving from human consent. Thomists have disagreed as to whether Thomas’s treatment of the law of nations
across these texts is consistent. Domingo Báñez understands
Thomas to use the term “law of nations” equivocally, adopting
the sense of Isidore in the Prima secundae (q. 95) and the sense
of the jurists in the Secunda secundae (q. 57), without a
substantive contradiction in position.25 Jacques Maritain holds

21

Quodl. II, q. 4, a. 2 (Leonine ed., 25:223).
STh II-II, q. 10, a. 12 (Leonine ed., 8:94).
23
“Et hoc modo communis omnium possessio, et omnium una libertas, dicitur esse de
iure naturali, quia scilicet distinctio possessionum et servitus non sunt inductae a natura,
sed per hominum rationem, ad utilitatem humanae vitae. Et sic in hoc lex naturae non est
mutata nisi per additionem” (STh I-II, q. 94, a. 5, ad 3 [Leonine ed., 7:173]). I follow the
Freddoso translation over the Dominican Fathers in translating “induced not by nature
but through the reasoning of men.”
24
In addition to personal property, servitude is another institution added to the ius
naturale by reason (I Polit., lect. 4; STh I-II, q. 94., a. 5, ad 3).
25
Domingo Báñez, O.P., Decisiones de iure et iustitia (Venice, 1595), 12b.
22

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that Thomas is only apparently inconsistent, and that he uses
“law of nations” in the same sense in every text as the rationally
deduced secondary precepts of the natural law. Maritain thus
holds that, for Thomas, private property is an institution strictly
necessary and demanded by the natural law, for it is “added” only
in the sense of being discovered by reason to be such a secondary
precept of the natural law.26 Francisco de Vitoria represents a
contrary view, namely, that Thomas contradicts himself across
the various texts, for what Thomas says in the Prima secundae
(q. 57, a. 3), “speaks against those things which he says in this
article [I-II, q. 95, a. 4].”27 In a later section we will discuss
Maritain’s line, but it is to the line of interpretation initiated by
Vitoria we now turn.
II. VITORIA’S SALAMANCAN LINE
Responding to Spanish adventuring in the Americas, Francisco
de Vitoria established a new line of Thomistic political theology
that explored questions of political power and human rights in
an international context. His famous releccio evaluating the
Spanish claims to the lands of the Amerindians, De indiis of 1539,
hinges on the right of communication and travel that belongs to
the law of nations (q. 3, a. 1). Yet Vitoria’s most extensive treatment of ius gentium is not found in De indis, but in his
commentary on the Secunda secundae. Vitoria interprets
Thomas’s doctrine of ius gentium as a body of universal positive
institutions (that is, specifications, determinationes) added to the

26
Jacques Maritain, La loi naturelle ou loi non écrite (1950), in Œevres complètes, ed.
Jean-Marie Allion and others (Fribourg: Éditions Universitaires, 1999), 16:733-38; idem,
Man and the State (Washington, D.C.: The Catholic University of America Press, 1998),
98-99; Paul M. Van Overbeke, “Saint Thomas et le droit: Commentaire de IIa-II[ae],
q. 57,” Revue Thomiste 55 (1955): 538-64, albeit with serious reservations (ibid.,
560-61).
27
Francisco de Vitoria, O.P., Comentario al tratado de la ley (ed. Vicente Beltrán de
Heredia, O.P. [Madrid: Consejo Superior de Investigaciones Cientificas, 1952], 29); see
also Peter Haggenmacher, Grotius et la doctrine de la guerre juste (Paris: Presses
Universitaires de France, 1983), 327-33.

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natural law by agreement of the human race; this would become
the common opinion of Thomists for two hundred years.28 In this
section, I will describe this Salamancan line as held by the leading
figures of the Salamancan School. I will first give their general
definition of the law of nations and then outline the implications
of their definition for changes in social teaching. Next I will
analyze the components of their definition of the law of nations,
addressing some speculative concerns along the way.
Following Vitoria, the Thomists of the Salamancan line define
the law of nations as positive law, located midway between
natural and civil law, morally necessary for keeping the natural
law without being strictly deduced therefrom, founded in a
human agreement, and promulgated by universally or near
universally adopted customs. Báñez, for example, distinguishes
the law of nations from natural law and civil law by noting that
those things which have been introduced by the law of nations are neither
principles known per se nor are they things which are deduced from them by
necessary consequence, although they are gathered from them by a consequence
so greatly probable and useful to human society that there are no nations which
do not admit such a consequence.29

Suárez similarly notes that the law of nations “is not an evident
deduction” from the law of nature but is nonetheless “very near
to the law of nature” and “so greatly useful and agreeable with
nature” that it is accepted by all.30 On account of its proximity to
28

Annabel S. Brett, Changes of State: Nature and the Limits of the City in Early Modern
Natural Law (Princeton, N.J.: Princeton University Press, 2011), 13: “Vitoria followed
Aquinas in seeing the ius gentium as a function of natural reason but departed from his
position in [the Secunda secundae] by understanding it as a kind of positive right.
Furthermore, he provided a new source of its positivity in the consensus of all mankind.”
29
Báñez, De iure et iustitia (Venice ed., 12b): “Deinde probatur conclusio ex
differentia inter ius naturae et inter ius gentium et ius civile positivum. . . . At vero ea quae
introducta sunt iure gentium neque sunt principia per se nota neque ex illis per
necessariam consequentiam deducuntur, quamvis colligantur per consequentiam usque
adeo probabilem et utilem humanae societati, ut nullae sint nationes, quae talem
consequentiam non admittant.”
30
Francisco Suárez, S.J., Tractatus de legibus ac Deo legislatore (1613), 2.19.9 (ed.
Luciano Pereña et al. [Madrid: Consejo Superior de Investigaciones Cientificas, 1971-81],

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and moral necessity for keeping the natural law, as well as its
universally binding character, one can call the law of nations a
“natural law” secundum quid. In contrast to natural law, which is
immutable, the law of nations can change and develop as positive
law, at least in part. Proponents of the Salamancan line ground
the binding character of the law of nations in the quasi-political
authority of the entire human race, which promulgates the ius
gentium by customs whose utility for attaining the ends of the
natural law under a certain set of social conditions is easily
recognized by rational creatures. The law of nations admits of
different types of social necessity, as clarified above all by Suárez,
consisting either in the universal adoption of a custom by each
people (e.g., personal property), or in institutions relating
peoples to one another (e.g., inviolability of ambassadors, law of
war, right of travel and communication).
For four hundred years, until Maritain, Thomists typically did
not speak of the ius gentium as the part of natural law specific to
the inclinations of man qua rational being (in contrast with ius
naturale, those natural inclinations shared generically with all
animals). Following Vitoria, Thomists instead spoke of ius
gentium as a body of universal, positive institutions “almost” or
“morally” necessary for keeping the social demands of the natural
law and of ius naturale as more or less equivalent to lex naturalis.
For these Thomists, the law of nations is universally binding yet
mutable within a certain range, namely, the set of permissible
means to natural-law ends. The law of nations may be identified
with the natural law from the existential perspective of any
person living in this or that age on account of the force and scope
of ius gentium. At the same time, the law of nations can change
with changing social conditions, should a custom be recognized
as better realizing what the natural law demands. In this

4:136): “Eo vel maxime quod ea quae ad hoc ius pertinent, et pauca sunt, et iuri naturali
valde propinqua; et quae facillimam habent ab illo deductionem, adeoque utilem et
consentaneam ipsi naturae, ut licet non sit evidens deductio tanquam de se omnino
necessaria ad honestatem morum, sit tamen valde conveniens naturae et de se acceptabilis
ab omnibus.”

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BARRETT H. TURNER

existential-historical perspective, the ius gentium is a kind of
evolving natural law.
The ius gentium is a “middle” category between natural law
and positive (civil) law, but it is essentially positive (involving
specifications/determinationes), dependent on human agreement
for both its content and its promulgation.31 In arriving at this
position, the proponents of the Salamancan line had to reinterpret Thomas’s harmonization of his own natural-law doctrine
with Isidore and the Roman jurists.32 The jurists “commonly
31

Francisco de Vitoria, O.P., Comentarios a la secunda secundae de santo Tomás, IIII.57.3 and II-II.66.2 nn. 4-5 (ed. Vicente Beltrán de Heredia, O.P., 6 vols. [Salamanca:
Biblioteca de Teólogos Españoles, 1932-52], 3:12-17 and 3:325-26); Domingo de Soto,
O.P., De iustitia et iure, libri decem 1.5.4, 3.1.3, and 4.2.2 (Salamanca, 1553 [44-46,
196-98, and 288-91]); Cano, Vat. Lat. 4648, f. 3-4 (Pereña, ed., 248-49); Báñez, De iure
et iustitia, II-II.57.3 (Venice ed., 13a); Luis Molina, S.J., De iustitia et iure opera omnia
1.5 (Venice, 1593-1611 [13]); Molina, Lisboa, Biblioteca Nacional, Fundo Geral 2841,
f. 69-73 (Pereña, ed., 270); Suárez, De legibus, 2.17, 19, 20 (Pereña, ed., 4:100-111,
124-49); 7.4.3-5 (Vivès ed., 6:145-47). Citations of the Salamancans will include name,
abbreviated title, and location (book, question, article or book, chapter, paragraph),
followed by volume and page number of any critical edition. Citations of Soto and Cano
manuscripts refer to those appended to Francisco Suárez, S.J., Tractatus de legibus ac Deo
legislatore (1613), ed. Luciano Pereña et al. (Madrid: Consejo Superior de Investigaciones
Cientificas, 1971-81), vol. 4, and are cited by manuscript number, “Pereña, ed.”, and then
page number. The first three books of Suárez’s De legibus is cited according to this same
critical edition. For further books, the edition of De legibus contained in the Vivès Opera
omnia is cited by volume and page (Francisco Suárez, S.J., Opera omnia, 9th ed., ed. M.
André, and C. Berton, 28 vols. [Paris: Ludovicus Vivès, 1856]).
The manuscript of Soto that Pereña transcribes (Roma, Biblioteca Vaticana, Ottob. lat.
781 [or 871], f. 6-7) is from Soto’s October 1540 lectures on Summa theologiae, II-II,
qq. 57-58. These lectures antedate his published treatise De iustitia et iure; the manuscript
includes Soto's own marginal corrections and additions (Vicente Beltrán de Heredia,
Domingo de Soto: Estudio biografico documentado [Salamanca, 1960], 583-84; Jaime
Brufau Prats, “Introducción general,” in Domingo de Soto, Relecciones y opusculos, vol.
1, Introducción general, De Dominio, Sumario, Fragmento: An liceat . . . [Salamanca:
Editorial San Esteban, 1995], 32-34). There is confusion in the literature as to whether
this manuscript is numbered 781 or 871.
32
Billuart, for example, in including the law of nations under ius positivum, admits
that “although Saint Thomas does not openly teach this conclusion here [IIaIIae.57.3 co.],
however he teaches it openly enough when he resolves the arguments to the contrary”
(Carolus Renatus Billuart, Summa sancti Thomae hodiernis academiarum moribus
accommodata, 9th ed., 9 vols. [Paris: Letouzey et Ané, 1900], 4:4b).

IUS GENTIUM AS DEVELOPING MORAL LAW

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distinguish natural law [ius naturale] from the law of nations in
that natural law is common even to brute animals, while the law
of nations is proper to humans.”33 To the Salamancans, who had
absorbed Thomas’s rational inclination model of the natural law
and who equated lex natura with ius naturale, the jurists’
definitions of natural law and the law of nations could only seem
a category error.34 To be sure, Vitoria and other Salamancans
thought the disagreement was partly semantic,35 a disagreement
caused by Thomas slipping back and forth between two different
verbal taxonomies.36 Ultimately, however, the Salamancans
rejected the jurists’ system because it identified too closely the
material element of natural law with the formal, rational element.
The jurists “extend the law of nations too far” insofar as they
include the natural moral law in it.37 On the other end, the jurists
extend what they call the natural law to brute animals, who do
not participate in the eternal law by reason. According to Soto,
the jurists’ use of the term ius naturale fails when one sees that
“there are many natural laws [naturalia iura] which are
particularly fitting to human but not to brute nature.” This would
include the precepts of the Decalogue regarding divine worship
and lying, even if material overlap with animal behavior exists in
certain moral norms, as in the male-female basis of marriage.38

33

Suárez, De legibus, 2.17.3 (Pereña, ed., 4:102), who has in mind Ulpian’s formula:
“The law of nations is what human peoples use . . . natural law [ius naturale] is what
nature has taught all animals” (Dig. 1.1.1.3).
34
Whether lex and ius are more or less synonymous terms in Thomas is debated. See
Brian Tierney, The Idea of Natural Rights: Studies on Natural Rights, Natural Law, and
Church Law 1150-1625 (Grand Rapids, Mich.: Eerdmans, 1997), 22-27.
35
Even as he recognizes that the disagreement is of a semantic nature (“Disputatio est
de nomine . . .”), Vitoria calls the theologians’ “proper” use of terms “better” than the
Jurists, who “[take] them in an enlarged way” (Vitoria, Comentarios, IIaIIae.57.3 n. 2
[Beltrán de Heredia, ed., 3:14]).
36
Vitoria, Comentarios, IIaIIae.57.3 n. 2 (Beltrán de Heredia, ed., 3:13); Molina, De
iustitia et iure, t. 5 d. 69 a. 3 (Venice ed., 5:421-22); Báñez, De iure et iustitia, IIaIIae.57.3
(Venice ed., 12a); Suárez, De legibus 2.17.4 (Pereña, ed., 4:103).
37
Vitoria, Comentarios, IIaIIae.57.3 n. 2 (Beltrán de Heredia, ed., 3:13). Soto uses the
same phrase in De iustitia et iure 3.1.3 (Salamanca ed., 198a).
38
Soto, De iustitia et iure 3.1.3 (Salamanca ed., 198a).

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Suárez is even less optimistic than Soto about finding a
material convergence between a purported animal-level natural
law and a rational, human-level natural law, since even the lowest
human inclinations semper involvit modum rationalem. Thus
“even in the same work materially common with brute animals,
the natural law prohibits many things for humans from which
brutes are not prohibited by natural instinct,” such as, “wandering concubinage or simple fornication or sexual congress with
mother or sister.”39 On the other hand, “it would be absurd to
deny that the precepts of worshipping God, honoring one’s
parents and neighbor . . . returning a deposit, keeping faith,
speaking the truth,” and so on are part of the natural law (ius
naturale).40 These things are natural to rational animals and are
traditionally assigned to the natural law, not the law of nations.
If the jurists are correct, there would be no natural law against
fornication, because brute animal nature does not observe
generically any law against promiscuous coupling.41 Vitoria
argues similarly: if we should extend “natural right” to brute
animals, why stop at those inclinations shared by humans and
brute animals? Why not include the natural inclination of selfpreservation found among all irrational beings? Fire would then
follow the natural law, since it also seeks to conserve itself in
being, yielding a natural law “to ascend and to burn,” which is
obviously excessive.42 Accordingly, the Salamancan line starts
from a rejection of the jurists’ ius naturale-ius gentium distinction, at least as used by those jurists who identify ius naturale
with absolute adequation flowing from animal bodies and ius
gentium with specifically rational adequations flowing from
consequences.43 In this, the Salamancans distance themselves
39

Suárez, De legibus 2.17.6 (Pereña, ed., 4:106).
Ibid. (Pereña, ed., 4:107).
41
Suárez, De legibus 2.17.6 (Pereña, ed., 4:107); see also Vitoria, Comentarios,
IIaIIae.57.3 (Beltrán de Heredia, ed., 3:13-14).
42
Vitoria, Comentarios, IIaIIae.57.3 (Beltrán de Heredia, ed., 3:13).
43
See also Cano, Vat. Lat. 4648, f. 3-4 (Pereña, ed., 248); Báñez, De iure et iustitia,
IIaIIae.57.3 (Venice ed., 12a); Molina, De iustitia et iure, t. 5, d. 69, a. 3 (Venice ed.,
5:421-22).
40

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359

from Thomas’s attempt to accommodate the jurists’ use of the
terms.
At the same time, the Salamancans reject universality among
humans as a sufficient means of distinguishing the law of nations
from the natural law. The jurist Gaius defined the law of nations
as “what natural reason constitutes among all humans,” and
therefore “nearly all nations use it” (Dig. 1.1.9). The main
objection the Salamancans raise to this definition is the principle
Thomas himself conveys in his commentary on the Ethics (V
Ethic., lect. 12), namely, that positive law (ius positivum) does
not arise necessarily from natural law (ius naturale), and that
whatever follows as a strict conclusion from natural law is in fact
natural law.44 Vitoria argues that if something in the law of
nations follows “by good consequence” from the natural law,
then “it already would be natural law.”45 No matter how distal, a
strict deduction from natural-law principles remains a precept of
the natural law and is essentially distinct from a specification or
addition to the natural law. Vitoria gives the prohibition of
fornication as an example of a “tertiary precept” of the natural
law that is distal from the first moral principles and
correspondingly difficult for the uneducated to know with
certainty. Nonetheless the prohibition of fornication remains a
natural-law prohibition, since it follows by good consequence
from natural-law principles pertaining to marriage and the
procreation and education of offspring.46 The other Salamancans
agree. No matter how distant the deduction, if a conclusion
follows necessarily from natural-law principles per se nota, then

44
“Uno modo sicut conclusio ex principiis, et sic ius positivum vel legale non potest
oriri a iure naturali. . . . et ideo necesse est quod quicquid ex iusto naturali sequitur quasi
conclusio sit iustum naturale” (Leonine ed., 47:305).
45
Vitoria, Comentarios, IIaIIae.57.3 n. 4 (Beltrán de Heredia, ed., 3:16). Brett is
therefore incorrect to say that it was Suárez and not Vitoria who pointed out that ius
gentium cannot be a body of strictly necessary conclusions from natural law without being
natural law itself: Annabel S. Brett, “Francisco de Vitoria (1483-1546) and Francisco
Suárez (1548-1617),” in The Oxford Handbook of the History of International Law, ed.
Bardo Fassbender and Anne Peters (Oxford: Oxford University Press, 2012), 1089.
46
Vitoria, Comentarios, IIaIIae.57.2 n. 4 (Beltrán de Heredia, ed., 3:9-10).

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BARRETT H. TURNER

the conclusion belongs to natural law and not to the law of
nations.47
While defining the law of nations as essentially a body of
universal positive law, those in the Salamancan line admit that
the law of nations is natural in the sense that it is morally
necessary for keeping the natural law under a certain set of social
circumstances. The ius gentium does have a kind of secondary
naturalness in the Salamancan doctrine owing to its usefulness in
keeping the natural law. This is distinguished from the usefulness
of civil law insofar as the law of nations is used by all or nearly
all peoples while civil law is more parochial. In this way the
Salamancan line reinterprets Thomas’s category of the naturally
just secundum quid. For example, Thomas distinguishes between
nature’s primary and secondary intentions (IV Sent., d. 36),
saying that nature intends generation primarily and intends only
secondarily the corruption necessary for generation. Soto offers
this as an example of how nature can primarily intend liberty for
all, but secondarily intend slavery for those who should be
punished. Hence slavery is “not natural in the first way . . . but is
accidentally natural, that is, under the condition of sin it is given
as a punishment.”48
Accordingly the Salamancan line reinterprets Thomas’s
second sense of ius naturale (in STh II-II, q. 57, aa. 2-3)—that
which is naturally right on account of what follows from it—as a
category of utility for keeping the other ends of the natural law.49
Personal property is not naturally right absolutely, but rather on
account of its utility for the common use of goods while
preserving peace in society. This utility is not strictly deduced by
natural reason from natural-law principles. Rather, the Salaman47

To cite just one example, see Suárez, De legibus 2.17.8 (Pereña, ed., 4:108); 2.17.9
(Pereña, ed., 4:110).
48
Soto, de dominio, n. 25, in Domingo de Soto, O.P., Relecciones y opusculos, ed.
Jaime Brufau Prats et al. (Salamanca: Editorial San Esteban, 1995-2011), 1:150: “Unde
servitus non est primo modo naturalis quia natura intendit libertatem, sed est de per
accidens naturalis, id est ratione peccati est data in poena.”
49
E.g., Vitoria, Comentarios, IIaIIae.57.3 (Beltrán de Heredia, ed., 3:12-14); Soto, De
iustitia et iure 3.1.3 (Salamanca ed., 198a).

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cans hold that human reason creates institutions that serve the
absolute, immutable ends of the natural law, but that these
institutions are not strictly necessary or required in order to keep
those ends. Indeed, the Salamancan line amplifies Thomas’s
explicit wording by distinguishing in what sense the derivation of
the law of nations from the natural law is necessary. As seen
above, a conclusio of human law appears to be strictly deduced
from the natural law, in Thomas’s thought. Although positive in
promulgation when contained in a civil code of law, the conclusio
itself is of the natural law. This is why conclusiones have their
force in part from natural law. On the other hand, determinationes are not deduced from natural-law principles, but are
specifications of natural law necessary for some matter required
for social life but not strictly demanded by natural law itself (e.g.,
tax brackets, traffic laws, zoning laws). Different political communities can have diverse civil laws precisely because of this latter
type of derivation of human law from natural law. The Salamancans seem to distinguish yet another sense in which something
can be a conclusion from natural law without being strictly
deduced from it, with the concept of “moral necessity.” The law
of nations is, to use Vitoria’s phrase, “almost necessary” (pene
necessarium) in the sense that it would not be morally possible to
keep the natural law without its panoply of institutions and
customs.50 In the strictest sense, however, the law of nations is
actually a body of universal specifications of the natural law.
To understand how there can be such universal specifications,
we should recall something Thomas says about private property
(STh I, q. 98, a. 1, ad 3): the institution is necessary in the current
state of mankind for avoiding discord on account of common
possession, while “in the state of innocence” common use would
have been possible due to the “absence of every danger of discord.” Yet after the fall, the common ownership of property may
still be observed “among many good men.” Therefore, a human
institution (private property) can be described as necessary for
50
Vitoria, Comentarios, IIaIIae.57.3 (Beltrán de Heredia, ed., 3:16). See also his De
temp. 1.3; De indiis 3.1.2. See also Cano, Vat. Lat. 4648, f. 3-4 (Pereña, ed., 248).

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the social peace demanded by the natural law without being
absolutely necessary.51
The Salamancans assert on this basis that the institutions of
the law of nations are “almost necessary” for keeping the natural
law. In interpreting question 57, article 3 of the Secunda secundae
and other texts, they strike a balance between regarding the ius
gentium as quasi-natural regarding it as being essentially positive
law promulgated by human consent. Soto clarifies that this form
of necessity is
not simply necessary, but by another mode dependent on human agreement. . . .
When Thomas says that the law of nations is inferred from natural law [ex iure
naturali] as a conclusion, he doesn’t understand this as by a totally necessary
consequence . . . but he understands that it follows by a certain natural
convenience.52

51
See Thomas’s comments regarding “natural and absolute necessity” stemming from
material and formal causality (STh I, q. 81, a. 1).
52
“Scilicet quod ius gentium sit illud quod non est simpliciter necessarium, sed aliquo
modo dependet ex consensu hominum. . . . quando sanctus Thomas dicit ius gentium
inferri ex iure naturali tamquam conclusionem, non intelligit per consequentiam omnino
necessariam . . . sed intelligit ut sequatur per quandam convenientiam naturalem.” See
also Soto, De iustitia et iure 3.1.3.ad 2 (Salamanca ed., 198a); De dominio n. 22 (in Soto,
Relecciones y opusculos, 1:142-44). To identify a Salamancan consensus about property
in general is not to deny substantive divergences in particular. For example, Soto takes a
half-way position on private property that does not fit neatly within the Salamancan line
that property is not absolutely but only morally necessary for keeping the natural-law
command to live in society peacefully. On the other hand, he attributes to the natural law
a command that a division of possessions be made, and to the law of nations the actual
enacting or establishing of such a division (De dominio n. 22). He calls these the first and
second intentions of the natural law, making the institution of property in the law of
nations seem more like a strict demand of the natural law (much like St. Thomas’s use of
primary and secondary precepts when discussing polygamy in his Sentences commentary).
Cajetan, by contrast, attributes to the law of nations that a division should be made, and
to “positive law” (meaning civil law) that this field would belong to this or that man (see
his commentary on IIaIIae.66.2 in the Leonine Omnia opera, 9:86). Báñez and Billuart
attribute the moral necessity of property at least in part to the condition of human sin, to
“the malice of men” (Báñez, De iure et iustitia [Venice ed., 12b-13a]), or “from the
corruption of nature” men regard their private advantage as greater than the common
good (Billuart, Summa sancti Thomae 4:4b).

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Therefore, the “necessity” of the law of nations is a moral and
fitting necessity, not a necessity strictly deduced from the natural
law, as for example the prohibition of murder is deduced strictly
from the first principles of natural law. Other theologians in the
Salamancan line agree with Vitoria and Soto, speaking of the
necessity of the law of nations as “fitting,” “not absolute,” and
“useful” for obtaining a certain end.53 An example they
frequently use is the inviolability of ambassadors, without whom
it would be difficult to observe the natural-law command to live
at peace with other men. Yet the inviolability of ambassadors is
not so absolutely necessary that two warring nations could not
mutually revoke this custom without violating natural law.54
The law of nations, therefore, is a body of universal specifications (determinationes) of the natural law that are morally
necessary for keeping the natural law. They are institutions so
universally convenient for keeping the natural law in any given
age, with its set of social conditions, that from the existential
perspective of a person within that age, the law of nations may
be practically indistinguishable from natural law. For this reason,
Báñez observes that people are not accustomed to calling ius
gentium positive law, since it is so close to the natural law and
observed everywhere, just like the natural law.55 The law of
nations then is composed of those specifications that are so useful
for keeping the natural law that they can be called—albeit
improperly—“natural,” “necessary,” and even “conclusions” of
the natural law.
The secondary, derivative use of these terms has confused
even erudite commentators on the Salamancan line. For example,
Soto refers to the deliverances of the law of nations as
53

Cano, Vat. Lat. 4648, f. 3-4 (Pereña, ed., 248-49). See also Báñez, De iure et iustitia,
IIaIIae.57.3 (Venice ed., 12b); Molina, Lisboa, Biblioteca Nacional, Fundo Geral 2841,
f. 69-73 (Pereña, ed., 270); Suárez, De legibus 2.17.9, 2.19.9 (Pereña, ed., 4:109-11,
136); Billuart, Summa sancti Thomae, 4:5a: “neque conclusio sic necessario deducta, sed
tantum utilis et congruens humanae societate.” See STh I, q. 82, a. 1 on “necessity from
the end” (final causality).
54
Báñez, De iure et iustitia (Venice ed., 13b).
55
Ibid. (Venice ed., 13a).

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“conclusions” from the principles of the natural law when
commenting on question 95, article 4 of the Prima secundae, a
text in which Thomas identifies the law of nations with those
positive laws derived from the natural law by way of conclusion.56
Soto’s adoption of the term “conclusion” to describe the law of
nations has elicited charges of inconsistency in his doctrine of ius
gentium from Suárez, Haggenmacher, and Höpfl, who claim that
the term commits Soto to arguing for a strict, even if lengthy and
difficult to establish, logical connection between the principles of
natural law and the law of nations.57 Hamilton notes to the
contrary that Soto means conclusio “in a loose sense” in De iure
et iustitia (1.5.4).58 Indeed, Soto elsewhere describes the law of
nations in Vitoria’s terms, as morally but not strictly necessary
deductions. He later clarifies his earlier remarks:
For when we said that the law of nations is elicited from principles of nature, it
is not to be understood that the illation is completely necessary, but that it is
fitting from the nature of the thing in order to such an end. For it does not so
necessarily follow from the necessity of cultivating fields or of their peaceful
possession to the division of lordship, as from that principle “what you should
not do to others etc.” is elicited “you shall not kill,” but rather because lordship
is most fitting and most expedient to that end.59

Again we see that the necessity of the law of nations is of the
looser sort, based as it is on the final cause rather than the essence
56

Soto, De iustitia et iure 1.5.4.
Suárez, De legibus 2.17.8, 2.19.3 (Pereña, ed., 4:108, 128); Haggenmacher, Grotius
et la doctrine de la guerre juste, 347; Harro Höpfl, Jesuit Political Thought: The Society
of Jesus and the State, c. 1540-1630 (Cambridge: Cambridge University Press, 2004),
302-3.
58
Bernice Hamilton, Political Thought in Sixteenth-Century Spain: A Study of the
Political Ideas of Vitoria, De Soto, Suárez, and Molina (Oxford: Oxford University Press,
1963), 100.
59
Soto, De iustitia et iure 3.1.3 (Salamanca ed., 198): “Quando enim diximus ius
gentium elici ex principiis naturae per viam illationis, non intelligitur quod illatio sit
omnino necessaria, sed rei naturae in ordine ad talem finem conveniens. Haud enim ex
necessitate colendi agros vel pacifice eorum possessionis consequitur tam necessario
dominiorum divisio, quam ex illo principio, Id ne facias aliis etc. elicitur, Non occides,
sed quia est illi fini congruentissimum atque expedientissimum.”
57

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of the natural law. Even Suárez, who earlier in his work charges
Soto with inconsistency, comes around to Soto’s loose use of the
term: “we understand, with Soto and others, that the precepts of
the law of nations are called conclusions of the law of nature not
absolutely and through a necessary illation, but by making a
comparison to the specification [determinatio] found in civil and
private law.”60 Despite sometimes calling the law of nations a
body of “conclusions,” the Salamancan line holds that the law of
nations consists of specifications of and not deductions from the
natural law, albeit universal ones.
In interpreting Thomas in this way, the Salamancans develop
in the law of nations a new Thomistic category of universal law
that is nonetheless capable of change. The law of nations is
mutable, unlike natural law proper.61 The mutability stems from
the fact that the law of nations is only morally necessary for
keeping the natural law under a certain set of conditions. Should
the conditions change, the possibility arises, at least in principle,
that the law of nations will change. The Salamancans foresee no
way to change the entirety of the law of nations, at least in part
on account of the difficulty of obtaining consent for a wholesale
change from the whole human race. In addition, the conditions
assumed in promulgating certain institutions, such as the need to
have private property in light of the likelihood of contentions in
society, would not seem to change universally. The Salamancans
do, however, envision the possibility of a partial mutation or
abrogation in the law of nations. This could happen in different
ways. One would be when a new custom emerges at the regional
level in light of regional circumstances, but then spreads to other
regions in the event that the custom be found more conducive to
keeping the natural law. Alternatively, the partial mutation could
happen when institutions of the law of nations no longer apply
to certain communities or times (e.g., mutual suspension of the
60
Suárez, De legibus 2.20.2 (Pereña, ed., 4:141): “cum Soto et aliis intelligimus
praecepta iuris gentium vocari conclusiones iuris naturalis non absolute et per necessariam
illationem, sed comparatione facta ad determinationem iuris civilis et privati.”
61
Vitoria, Comentarios, IIaIIae.57.3 n. 5 (Beltrán de Heredia, ed., 3:16-17);
IIaIIae.66.2 n. 5 (Beltrán de Heredia, ed., 3:326).

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use of ambassadors between two parties in a war; commonality
of property among religious or in the early Church).62
The primary example offered by the Salamancans themselves
for this kind of evolution in the law of nations is the elimination
of slavery in Christendom, both in itself and as a punishment of
an unjust aggressor in war. The right of victors to enslave their
enemies was one of the premier institutions of the law of nations
according to Roman law. Its utility had to do with resolving a
war. The loss of natural liberty was regarded as a just punishment
for the defeated, a merciful alternative to execution, and useful
for reducing the likelihood of later uprisings by dispersing the
population. Soto justifies the morality of such enslavement on the
grounds of justice and mercy: if an emperor has the power of
death, he has a fortiori the power to punish by servitude; and
slavery existed “from consent or agreement of men for the sake
of saving their lives.”63 Yet Catholic medieval culture eventually
eliminated slavery as it was found in Greco-Roman culture,
transmuting it into arrangements more conducive to mutual
dependence and personal liberty. By the time of the Salamancans,
even slavery as a punishment in war between Christian peoples
had been replaced by the practice of holding prisoners of war for
ransom. On the other hand, in war with Muslims, Christians
would reduce Muslim prisoners of war to perpetual slavery, and
vice versa. Vitoria even argues that it is sometimes lawful for the
victors in war to kill all enemy combatants, in order to prevent
later hostilities, yet this only applies to “the infidel” and not to
fellow Christians.64
This disparity between the way Christians treated Christian
prisoners of war and the way they treated Muslim prisoners of
war gave the Salamancans a ready-made example of how the law
of nations could be modified in part by the introduction of better

62

Báñez, De iure et iustitia (Venice ed., 13a); Billuart, Summa sancti Thomae, 4:4b.
Soto, De dominio, n. 25 (Relecciones y opusculos, 1:150). Vitoria likewise says that
executing prisoners of war is not prohibited by the natural law, but by the law of nations
(De iure belli 3.6).
64
Vitoria, De iure belli, 3.5
63

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institutions for keeping social peace, even at an international
level. Vitoria’s view is typical:
It is indeed possible to abrogate the law of nations in part . . . as the law of
nations is that captives in a just war should be slaves, but Palude says that this
is not done among Christians. For if the Spanish capture the French in war, the
French are captives but not slaves, because they are able to appear in court and
other such things, which however would not be permitted were they slaves.65

Soto, Cano, Báñez, Molina, and Suárez all make similar remarks
about this change in the law of nations regarding the impermissibility of slavery among Christians.66 Soto and Báñez attribute the change not merely to an abstract “spiritual responsibility
of human beings for one another” (pace Hamilton),67 but to the
formal sacramental brotherhood that informs a community of
nations by virtue of a common baptism. Hence some
Salamancans, such as Báñez, even speak of the change in the law
of nations being made “in favor of the gospel and of baptism”
and the “Church” as the promulgating authority of this change.
Were the law of nations identical to the natural law, he argues,
even the Church would not be able to introduce such an
abrogation, for the law of nature is immutable and grace does not
destroy nature.68 While faith does not exempt one from keeping

65

Vitoria, Comentarios, IIaIIae.57.3.5 (Beltrán de Heredia, ed., 3:16-17). See also De
iure belli 3.3, where Vitoria argues that to enslave even innocents among “the Saracens”
is permitted, “but since it seems to be accepted in the law of nations that Christians cannot
enslave one another, it is not lawful to enslave fellow-Christians, at any rate during the
course of the war.” Rather “one may take prisoners . . . but not to enslave them, only to
hold them to ransom” (De iure belli 3.3, translation from Francisco de Vitoria, O.P.,
Political Writings, ed. Anthony Pagden and Jeremy Lawrance [Cambridge: Cambridge
University Press, 1991], 318-19). For the Latin text, see Francisco de Vitoria, O.P.,
Relecciones jurídicas y teológicas, ed. Antonio Osuna Fernández-Largo et al., 2 vols.
(Salamanca: Editorial San Esteban, 2017), 2:284, 286.
66
Soto, De domino n. 25 (Relecciones y opusculos, 1:151); Cano, Vat. Lat. 4648, f. 3-4
(Pereña, ed., 248); Báñez, De iure et iustitia (Venice ed., 13b); Molina, De iustitia et iure
1.5 (Venice ed., 13); and Suárez, De legibus 2.20.8 (Pereña, ed., 4:147-48) and 7.4.6
(Vivès ed., 6:146).
67
Pace Hamilton, Political Thought in Sixteenth-Century Spain, 105.
68
Báñez, De iure et iustitia (Venice ed., 13b).

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the law of nations, Soto says, from “the decency of Christian
liberty” a custom could be introduced that changes the law of
nations, again using the example of Christians no longer enslaving each other as prisoners of war.69 The law of nations
becomes a progressive adjunct to the natural law, capable of
developing under new conditions and even in light of the gospel’s
progress in societies. This would not be possible if the law of
nations were intrinsically immutable, commanding what is per se
good or prohibiting what is per se evil.
The common opinion of the Salamancan line, however, is that
the law of nations cannot be abrogated or change in its entirety.
This is not from any natural necessity or intrinsic principle, but
from the difficulty of obtaining the consent of the nations to an
entirely new set of means for keeping the natural law, which
renders the possibility of an entire change “morally impossible.”70
Undoubtedly, one reason why the law of nations cannot be
entirely changed is that it is so close to the unchanging natural
law. It seems “morally impossible” indeed to say that the entire
experience of the human race in matters of this sort is in need of
total replacement. Suárez identifies two theoretically possible
ways of modifying the law of nations: the agreement of all
nations, or the gradual introduction of an alternative custom that
then prevails against current usage.71 Moreover, the advent of
political mechanisms for obtaining universal consent, such as the
United Nations Organization, calls into question whether such
change in the law of nations is still morally impossible.72
69

Soto, De iustitia et iure 4.2.2 (Salamanca ed., 290b).
Suárez, De legibus 2.20.8 (Pereña, ed., 4:147), 7.4.9 (Vivès ed., 6:147); Molina, De
iustitia et iure 1.5 (Venice ed., 13); see also Báñez, De iure et iustitia (Venice ed., 13a).
71
Suárez, De legibus 2.20.8 (Pereña, ed., 4:147): “Nihilominus tamen non repugnat
mutatio ex vi materiae, si nationes omnes consentirent vel si paulatim introduceretur
consuetudo contraria et paevaleret.”
72
Hamilton observes that the UNO as an instrument for capturing and enforcing
world opinion “would not sort ill with the ideas of Vitoria and Suárez” (Hamilton,
Political Thought in Sixteenth-Century Spain, 98 n. 1), even if international law is not
identical to the idea of the law of nations in Salamancan thought, on account of the fact
that modern international law consists of contracts between states. For more on the
differences between modern international law and the law of nations of the Salamancan
70

IUS GENTIUM AS DEVELOPING MORAL LAW

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Much less commonly, the Salamancans point to the condition
of sin (sub ratione peccati) as making parts of the law of nations
permanent in this life, for example, the need for personal
property to safeguard the peaceful use of the goods of the earth.
Universally abrogating the institution of personal property would
therefore be morally impossible. If this is so, certain institutions
of the law of nations may remain until the Second Coming. Yet
other institutions of the law of nations may outlive their
usefulness in later ages owing to a change in conditions, though
they were observed universally in prior ages.
One difficulty for the Salamancan line is explaining how a
body of universal positive law can be promulgated in diverse
societies apart from any formal political authority. If the law of
nations is not natural law proper, and since there was no
equivalent of the United Nations Organization when the
Salamancans wrote, it appears impossible for a universal body of
law to arise from reason by human agreement.73 The Salamancans, after treating this question rather occasionally at first,
settle upon the solution that universally adopted custom arose
with the “virtual consent” of the human race.74 The conclusion
arises from three premises: that political authority is vested first
in the people and transmitted to the ruler;75 that custom is one

line, see J. Th. Delos, O.P., Somme théologique: La justice; tome premier, 2a-2ae,
questions 57-62, 2d ed., trans. M. S. Gillet, O.P. (Paris: Desclée, 1948), 219-22.
73
Furthermore, Salamancan political theology argues that neither the pope nor the
Holy Roman emperor possessed universal political authority, against contemporary
civilian canonists and the extreme papalists. See, e.g., Vitoria, De potestate ecclesiae prior,
5.1 and De indiis 2.1-2. For the Jesuit theologians of the period, see Höpfl, Jesuit Political
Thought, 348-49.
74
That is, ex consensu/statuto humano. See, among others, Vitoria, Comentarios,
IIaIIae.57.3 nn. 1, 3 and IIaIIae.62.1 nn. 22-23 (Beltrán de Heredia, ed., 3:12, 14-15,
78-80); Suárez, De legibus 2.17.8 (Pereña, ed., 4:108-9).
75
This is clearest in the Jesuit theologians and in Cajetan, in whom the “transmission
theory” of political power was most developed and who built upon the Dominican
inheritance from Vitoria, who articulated more of a parallel between pope and king in a
“designation theory” (e.g., De potestate civili 1.5). See Yves R. Simon, Philosophy of
Democratic Government (Chicago: University of Chicago, 1951), 158-76; Höpfl, Jesuit
Political Thought, 224-30.

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way in which the people exercise this authority in establishing an
institution apart from a legislator; and that these dynamics apply
as much to the human race as a whole—a kind of universal people
or people of peoples—as they do to particular peoples.
In fact, the political authority of the entire human race limits
the power of any particular people. On this basis Vitoria appeals
to the law of nations to judge the validity of Spanish occupation
in the New World.76 The law of nations is true law made by the
human race as a whole: “The whole world, which is in a sense a
commonwealth, has the power to enact laws which are just and
convenient to all men; and these make up the law of nations.”77
For example, the right of a prince to restrain foreigners in order
to protect innocents who are not his subjects is based on “the law
of nations and the authority of the whole world.”78 Suárez says
the same:
The basis of this duty and right is because the human race, however divided into
various peoples and kingdoms, always has a certain unity, not natural alone, but
also in a sense political and moral, which discloses a natural precept of mutual
love and mercy extended to all, even foreigners and those from whatever
nation.79

Vitoria is just as clear that these laws are found in customs such
as that of not killing prisoners of war.80 In the case of the division
76

De indiis 3.1.
De potestate civili 3.4 (trans. in Vitoria, Political Writings, 40).
78
De iure belli 1.4 (trans. in Vitoria, Political Writings, 305). Suárez argues that the
right to wage war at all is from the law of nations, since there could have been ways of
repairing offenses other than warfare and thus warfare is not strictly necessary (De legibus
2.19.8).
79
Suárez, De legibus 2.19.9 (Pereña, ed., 4:135): “Ratio autem huius partis et iuris est
quia humanum genus, quantumvis in varios populos et regna divisum, semper habet
aliquam unitatem, non solum specificam, sed etiam quasi politicam et moralem, quam
indicat naturale praeceptum mutui amoris et misericordiae quod ad omnes extenditur,
etiam extraneos et cuiuscumque nationis.”
80
Vitoria, De iure belli 3.6: “But as many practices in war are based on the law of
nations, it appears to be established by custom that prisoners taken after a victory, when
the danger is past, should not be killed unless they turn out to be deserters and fugitives”
(trans. in Vitoria, Political Writings, 321).
77

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of possessions, Vitoria favors the explanation that all this
happened by “virtual and interpretive consent” when men in
history tacitly agreed to divide property “by each occupying his
place, leaving alone the places of others.” This virtual consent
“suffices for the law of nations, because the law of nations is
certainly established, as many hold, by that consent which is
virtual.”81 Cano likewise defines an institution as belonging to the
law of nations if “it is a custom observed among most nations
from the beginning of the world.”82 Suárez also extends this explicit position of Vitoria and the earlier Salamancans in his own
extensive analysis of “universal custom,” though some scholars
regard this as an innovation by Suárez.83
In summary, the Salamancan line established by Vitoria understands the law of nations as a mediating category between the
natural law and the civil law of any particular state, consisting of
morally necessary, positively constituted institutions added to the
natural law and promulgated by human consent, in order that the
natural law may be kept more easily in society and between
societies. The law of nations is valid everywhere, like natural law,
but the law of nations is not necessarily valid for all time, having
some degree of mutability similar to civil law. Since it is universal,
originating from the “quasi-commonwealth” of the whole world,
it is prior to any particular political community and places

81
Vitoria, Comentarios, IIaIIae.62.1 n. 23 (Beltrán de Heredia, ed., 3:79): “potuit fieri
divisio ex consensu virtuali et interpretativo occupando unusquisque suum locum,
dimittendo loca aliorum. . . . Et iste consensus sufficit ad ius gentium, quod ius gentium
certe ut plurimum constat solo isto consensu, scilicet virtuali.” Brian Tierney misses this
text and consequently understates the development of Vitoria’s thought on the question
of the grounding and origin of the law of nations. Instead Tierney assigns the
breakthrough on consent to Suárez (“Vitoria and Suarez on ius gentium, Natural Law,
and Custom,” in The Nature of Customary Law, ed. Amanda Perreau-Saussine and James
Bernard Murphy [Cambridge: Cambridge University Press, 2007], 110-14).
82
Cano, Vat. Lat. 4648, f. 3-4 (Pereña, ed., 249): “apud omnes nationes sit conseutudo
a plurimis observata a principio mundi, ut constat esse in his quae sunt iuris gentium.”
83
Suárez, De legibus 2.19.9 and 2.20.1, on the law of nations consisting in the
“customs” (mores, consuetudines), “use” (usus), and “tradition” (traditio) of the nations;
see also 7.4.3-5 on changing the universal customs found in the law of nations.

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demands on that community.84 For this reason, the law of nations
may seem existentially indistinguishable in moral force from the
natural law in a given age for the average person, but it differs
from natural law in that the law of nations can be modified.
Hence what is permitted or forbidden by the law of nations at a
given moment in time may change if conditions in society or
between societies change, as happened with the obsolescence of
enslaving prisoners of war in conflicts between nations in late
medieval Christendom.
III. MARITAIN’S NEO-THOMIST LINE
If the Salamancans understand ius gentium to be a body of
positive, customary law added to natural law but universally
binding, then the Neo-Thomist line initiated by Maritain
understands ius gentium to contain the full implications of the
natural law as better and better known and followed. These
implications are worked out by discursive reasoning in human
societies, in time and under the influence of the gospel of Jesus
Christ. The law of nations historically advances mainly in the
sense that our knowledge of the natural law’s unchanging

84

There is not space enough in this article to discuss Suárez’s precision of ius gentium
into ius intra gentes and ius inter gentes, the former composed of positive rights derived
from natural law but so fitting for keeping it that they are found in most civil codes or at
least common law; and the latter composed of positive arrangements between nations as
social entities, still grounded in some way in natural law. Scholars somewhat disagree as
to whether ius inter gentes is only customary or may include pacts between individual
nations, that is, whether Suárez would include what we call international law in ius
gentium. See Heinrich A. Rommen, The State in Catholic Thought: A Treatise in Political
Philosophy (repr.; Providence, R.I.: Cluny Media, 2016), 588-92; Hamilton, Political
Thought in Sixteenth-Century Spain, 106-9; Haggenmacher, Grotius et la doctrine de la
guerre juste, 349-51; John P. Doyle, “Francisco Suárez on the Law of Nations,” in Religion
and International Law, ed. Mark W. Janis and Carolyn Evans (The Hague: Martinus
Nijhoff, 1999), 109-12; Höpfl, Jesuit Political Thought, 303-4; Brett, Changes of State,
85-86; Brett, “Francisco de Vitoria (1483-1546) and Francisco Suárez (1548-1617),”
1090; Tierney, “Vitoria and Suarez on ius gentium, Natural Law, and Custom,” 121-24;
Brian Tierney, Liberty and Law: The Idea of Permissive Natural Law, 1100-1800
(Washington, D.C.: The Catholic University of America Press, 2014), 210-11.

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demands becomes increasingly clear, for example, in the
movement from polygamy to monogamy. Doubting the Whig
vision of history inherent in this position, later figures in the NeoThomist line modify Maritain’s position by emphasizing that
reason’s deductions from the natural law are conditioned by this
or that set of concrete social conditions. These later figures, such
as Yves Simon, shift the emphasis in what changes in the law of
nations from human reason being purified from erroneous
deductions to human reason responding to increasing civilizational complexity by positing conditional norms of natural law.
Where the Salamancans struggle to explain how reason universally promulgates a law, the Neo-Thomists propose a solution.
The law of nations is not natural law in the sense of Maritain’s
natural knowledge of moral first principles “by inclination,” but
further, strictly necessary deductions from those principles. As a
deduction made by reason, the ius gentium will resonate across
cultural boundaries and will find expression in various civil codes
without being limited to them. The law of nations would then be
“the common law of civilization,” to quote Maritain. Any change
in what the law of nations requires, Maritain and his disciples
argue, stems from a historical progression in knowledge from
confused, imperfect deductions to increasingly refined, distinct
knowledge of the natural law’s demands.
The essential features of Maritain’s interpretation are that the
law of nations is in content strictly deduced from the first
principles of the natural law by discursive reasoning; that the
reasoning that establishes the law of nations results in a positive
promulgation in the legal regimes of the various peoples; and that
the need for culture and time to achieve the deductions that
constitutes the law of nations also explains centuries-long
refinements or clarifications in the law of nations, for example,
the elimination of polygamy and slavery. On these major points,
Maritain is followed by Aubert, Simon, Labourdette, Finnis, and
others.85 At the same time, some of Maritain’s collaborators see
85
Aubert, Le droit romain dans l’œuvre de saint Thomas, 97-122; Benoît-Dominique
de La Soujeole, O.P., “Insaisissable ‘jus gentium’?,” Revue thomiste 92 (1992): 293-303;

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a need to supplement his theory with an emphasis on how natural
law relates to the changing conditions of social life. This section
accordingly expounds the origin and main features of Maritain’s
position, follows with Aubert and Finnis, and then closes with the
later positions of Labourdette and Simon. Labourdette and
Simon emphasize the necessity of certain civilizational conditions
for reducing what is in potency in the law of nations to act,
thereby mediating between Neo-Thomist and Salamancan
concerns.86
The modern groundwork for Maritain’s interpretation was
laid by Thomas Pègues and Odom Lottin.87 Breaking with the
Salamancan line, which had become the common opinion of
Thomists, Pègues characterizes the law of nations (le droit de
gens) in his Commentaire français littéral de la Somme
théologique as being constituted by reason making “immediate
and premier” deductions from the nature of things. Commenting
on question 57, article 3 of the Secunda secundae, Pègues says
that these conclusions are formulated “instinctively” by reason
and so “the law of nations is the same among all men.” Unlike
natural right (le droit naturel strict), which “is constituted by the
natural relation of things among themselves” (e.g., male-female,
parent-offspring), an act of ratiocination is needed to formulate
the law of nations. Pègues holds that the law of nations is strictly
deduced according to a natural necessity, not mere necessity on
account of an end or a moral necessity. Further, he warns against
conflating positive international law, which is composed of
treaties between nations, and the law of nations, which is not

John Finnis, Aquinas: Moral, Political, and Legal Theory (Oxford: Oxford University
Press, 1998), 190 n. 13, 196 n. 56, 200 n. 76, 268 ; Léon Charette, “Droit naturel et
droit positif chez saint Thomas d’Aquin,” Philosophiques 8, no. 1 (1981): 125ff.
86
Yves R. Simon, The Tradition of Natural Law: A Philosopher’s Reflections, ed. Vukan
Kuic (New York: Fordham University Press, 1992), esp. 146-58.
87
In Suárez’s day, some “modern Thomists” apparently held a position similar to
Maritain’s: “They think that the law of nations has an intrinsic necessity to its precepts.
Then it would only differ from natural law in that natural law is known without discursive
thought or with very easy discourse, while the law of nations would be grasped after many
and more difficult steps in reasoning” (Suárez, De legibus 2.17.8 [Pereña, ed., 4:108]).

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positive in the sense of being determined by reason.88 Maritain
was aware of the Commentaire, having relied on prior volumes
as early as 1909 in his initial study of Thomas.89 The volume
containing Pègues’s treatment of ius gentium antedates Maritain’s
treatment of the same by at least a decade. While Maritain does
not follow Pègues on a number of points, he does follow him in
reassigning the content of the law of nations to natural rather
than positive law. Pègues, for his own part, does not explain in
his commentary how the law of nations in the Secunda secundae
(STh II-II, q. 57, a. 3) harmonizes with the Prima secundae
(STh I-II, q. 95, a. 4).
Lottin’s monograph of 1931, in contrast, does attempt to
harmonize these disparate texts of Thomas. To explain how the
ius gentium could be positive in the Treatise on Law and yet
natural in the Treatise on Justice, Lottin focuses on the
authorities used by Thomas. If in question 95, article 4 of the
Prima secundae Thomas defends “the prestige of a received
authority” (Isidore) in distinguishing between natural right and
the law of nations, then in question 57, article 3 of the Secunda
secundae Thomas “gives the impression that to his mind the law
of nations, which is a work of natural reason, is a specifically
human natural right.”90 Lottin’s attention to Thomas’s use of
sources enables him to argue that the latter text reveals Thomas’s
own position, while the earlier text pays more deference to
Isidore. Maritain combines the notion that the law of nations is a
discovery of natural reason from Pègues with Lottin’s insistence

88
Thomas Pègues, O.P., Commentaire français littéral de la Somme théologique de
saint Thomas d’Aquin (Toulouse: Édouard Privat, 1925), 173-74.
89
Jean-Luc Barré, Jacques and Raïssa Maritain: Beggars for Heaven, trans. Bernard E.
Doering (Notre Dame, Ind.: University of Notre Dame, 2005), 268.
90
Lottin, Le droit naturel chez saint Thomas d’Aquin et ses prédécesseurs, 64, 67. Yet
Lottin’s observation about Thomas’s inconsistent application of the different senses of ius
gentium complicates Maritain’s line of interpretation. Sometimes Thomas uses ius
gentium in the positive institution sense, as with slavery after a just war; at other times he
uses ius gentium in the natural conclusion sense, as with property.

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that the text from the Treatise on Justice reveals Thomas’s mind
most directly.91
The cornerstone of Maritain’s own position is his common
distinction between the “ontological” and “gnoseological” elements of the natural law.92 According to the former, the rational
animal attains a knowledge “by inclination” of the first principles
of the natural law as “quasi conclusions.” According to the latter,
humans deduce by ratiocination further, strictly necessary
conclusions from the principles already known by inclination.
While the two categories overlap somewhat in content, the ius
gentium constitutes the “gnoseological” aspect of natural law.
The law of nations is positive only insofar as it is discovered and
promulgated by human reason in civil codes; it is natural insofar
as it contains whatever is strictly deduced from natural-law
principles. Thus, the law of nations is the natural law unfolded
gnoseologically. Maritain claims his distinction between knowledge by inclination and knowledge by deduction is the “only way
to realize the inner consistency” of Thomas’s texts.93 He thereby
affirms both the positivity of the law of nations, insofar as the
agreement of various legal codes evinces a universal process of
human moral reasoning, and also the naturalness of the law of
nations, insofar as it is composed of logically necessary conclusions from the natural law. He turns the premise of Thomas’s
Commentary on the Ethics against the Salamancans. For them,
the law of nations could not consist of implications of the natural
law strictly deduced from the natural law’s principles, for then
the law of nations would just be natural law. For Maritain, the

91

Lottin, Le droit naturel chez saint Thomas d’Aquin et ses prédécesseurs, 89 n. 4.
Maritain, La loi naturelle ou loi non écrite, 702-17, 733-38, 867-71; Maritain, Man
and the State, 84-101.
93
E.g., Maritain, Man and the State, 98 n. 13: “The only way to realize the inner
consistency of all that, and correctly to grasp the Thomistic distinction between Natural
Law and jus gentium, is to understand that a precept which is like a conclusion derived
from a principle of natural law but which in actual fact is known through inclination, not
through rational deduction, is part of natural law; but that a precept which is known
through rational deduction, and as a conclusion conceptually inferred from a principle of
natural law, is part of jus gentium.”
92

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law of nations is indeed just the name given to reason’s growing
awareness of what the natural law strictly demands.
What humans know by reason’s deductions from the natural
law is a knowledge more fragile than knowledge of the first
principles, which are known by inclination. It requires more reasoning to grasp these tertiary precepts than to grasp primary or
secondary precepts, and thus there is more opportunity for moral
error to creep into the process of discovery. On the basis of this
observation, Maritain infuses a progressive component to his
theory of natural law to explain how imperfect or false illations
from natural law were thought to be moral norms in prior ages.
Past civilizational epochs held as morally licit institutions and
customs that are in fact incompatible with natural law and human
dignity, such as divorce, polygamy, slavery, prohibition of
exogamy, permission of suicide, and so on. The natural law
therefore evolves not intrinsically but only in a progressively
clearer “gnoseological” awareness of the rights and duties of the
human person. As the collective, discursive reasoning of the
human race better grasps what is good and evil, the “common
law of civilization” develops from confused to precise moral
knowledge.94
While Maritain articulates a coherent account of how reason
promulgates the ius gentium, he stumbles over Thomas’s
examples of its specific institutions. In order to incorporate
Thomas’s comments on personal property into his account,
Maritain adopts the language of necessity from an end (that is,
convenience of means), especially in light of social conditions.
From the natural law (la loi naturelle) comes humankind’s joint
title to the goods of the earth. Yet “in reason of the finalities of
the common good,” the law of nations (droit des gens) establishes
private ownership by reason “according to the mode of necessity.” The institution of property accounts for what motivates
human work and protects the individual from the community. At
the same time, Maritain absolutizes personal property as a
“necessary conclusion, not contingent,” thereby equivocating
94

Maritain, La loi naturelle ou loi non écrite, 863-80.

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between necessity based on final causality (a necessity of means
toward an end) and natural or absolute necessity.95 Maritain
cannot quite solve the ambiguity of private property in Thomas’s
texts.
Jean-Marie Aubert’s historical study of Roman law in Thomas
argues that Thomas successfully harmonized his account of
natural law with the formulae of the Roman jurists, resulting in
just the kind of law-of-nations doctrine described by Maritain.96
Some of his conclusions are as follows: lex naturalis and ius
naturale are not equivalent; ius gentium is specifically human
because it discloses what is naturally just according to an act of
reason eliciting ethical implications from the natures of things;
ius gentium contains strict conclusions from the lex naturalis in
content even as these may also be civil laws; and therefore ius
gentium is not ius positivum, let alone ius civile (which are
specified by reason).97 At the same time, Aubert can only fit all of
Thomas’s comments on private property into the category of
conclusio from the natural law by omitting Thomas’s comments
about property being from “human agreement” and belonging to
ius positivum (“secundum humanum condictum, quod pertinet
ad ius positivum” [STh II-II, q. 66, a. 2, ad 1]).98 Again, Thomas’s
actual treatment of specific institutions belonging to the law of
nations remains a thorn in the side of the Neo-Thomist line.
John Finnis also follows Maritain in identifying the law of
nations as a “matter of natural law/right.”99 While ius gentium is
positive law in the sense that it comprises a section of “the whole
of the law administered by a state’s courts,” nonetheless the ius
gentium, that is, “the law about murder, theft, rape, and so forth
. . . is wholly or substantially part of, or a deduced conclusion
from, the permanent principles and precepts of the natural

95

Ibid., 740-41.
Aubert, Le droit romain dans l’œuvre de saint Thomas, 97-122.
97
Ibid., 102-8, 120.
98
Ibid., 116.
99
Finnis, Aquinas, 196 n. 56, where he assigns pacta sunt servanda to the law of
nations.
96

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law.”100 A further example would be laws pertaining to emptio et
venditio, which “are matters of positive law . . . [yet] in their
general structure are so necessary to a just social life that they are
a matter of deduction from basic moral (natural law) principles .
. . and can be called ius gentium—law common to all peoples—
as distinct from ius civile.”101 Finnis admits, however, that
Thomas’s texts on private property do not fit: “Aquinas’s
location of the institution of property in the domain of ius
gentium . . . does little or nothing to clarify” in what way property
is “not natural.”102 Like Maritain, Finnis must characterize
personal property as strictly natural in order to harmonize
Thomas’s texts.
Marie-Michel Labourdette and Yves Simon, later adherents of
this Neo-Thomist line, narrow the gap between the Salamancans
and Maritain. They modify Maritain’s line by emphasizing that
the natural law progresses more in the sense that its tertiary
demands are actuated by social conditions which are historically
situated and subject to change. The law of nations, then, is the
natural law’s demands under a social condition. Labourdette and
Simon accordingly share with the Salamancans a greater
willingness to discuss the law of nations as a changing natural
law, not merely a change in human knowledge of the natural law.
The first of these scholars is Marie-Michel Labourdette.103
100

Finnis, Aquinas, 268, giving a more definite meaning to STh I-II, q. 95, a. 4 than
the text itself gives. In a footnote, Finnis adds that “Aquinas does not adopt the theory
suggested in Justinian’s Digest 1.1.5 and Institutes 1.2.2, that in whole or part the ius
gentium is required by reason only in view of certain wrongful or other bad features of
the human situation (e.g. wars).” This is true in the main; see also Aubert, Le droit romain
dans l’œuvre de saint Thomas, 117-18. Even so, Thomas does make a contrary comment
about the division of goods in STh I, q. 98, a. 1, ad 3, where he declares personal property
unnecessary in “the state of innocence” and “even now among many good men.” This is
undoubtedly the source of the Salamancan treatment of common property in the Acts of
Apostles and among religious congregations as proof that personal property is not strictly
necessary.
101
Finnis, Aquinas, 200 n. 76.
102
Ibid., 190 n. 13.
103
I am drawing here on La Soujeole’s exposition of Labourdette, in “Insaisissable ‘jus
gentium’?,” 293-303. At the time of La Soujeole’s writing, only photocopies for student

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Labourdette’s commentary on question 95, article 4 of the Prima
secundae and question 57, article 3 of the Secunda secundae does
not deviate in the main from the other Neo-Thomists. He
identifies ius gentium as flowing from “nature considered with
the consequences that imply such and such situation, natural right
not entirely inscribed in nature, and the formulation of the
natural law by way of conclusion.”104 Labourdette clarifies that
the natural law’s direction “is grasped at the plane of synderesis”
as nature rationally understood (ius gentium), but that what is
naturally right (ius naturale) is inscribed in our nature. Natural
law’s direction must account for ius naturale even as it rises above
it. For example, marriage and the education of children is built
upon natural male-female complementarity even as the guidance
of reason raises the human intention of such coupling to a higher
plane.105 Nature as reasonable requires a work of reason to unroll
further conclusions from the principles of natural law. By
conceiving of reason’s work as a sort of positive promulgation,
Labourdette harmonizes the positivity of the law of nations in the
Treatise on Law with the law of nation’s proximity to ius naturale
in the Treatise on Justice.106 Accordingly, the ius gentium of
Thomas is natural law and not a prototype of international law,
although international law can be drawn from the law of nations.
All the same, Labourdette adds an element of conditional
positivity to the law of nations that Maritain lacks. The law of
nations “derives from human nature but supposes a certain state,
a set of historical circumstances outside of which nature does not
manifest any demand because in fact the problem [of a moral

use of Labourdette’s “long course” on the Secunda pars were available (293 n. 1). Since I
began writing this article, printed volumes have begun to appear. Accordingly, I have
updated La Soujeole’s citations of Labourdette’s commentary in the footnotes that follow,
giving the more recent published citation first with the page of the photocopy available
to La Soujeole in brackets.
104
Marie-Michel Labourdette, La justice, vol. 12 of “Grand cours” de théologie
morale (Parole et Silence, 2018), 42 [22].
105
Ibid.
106
Labourdette, La justice, 43 [23].

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381

norm] does not pose itself.”107 To illustrate, Labourdette claims
that there can be no question of how to formulate an international law derived from natural-law principles without the
existence of nation-states. Nation-states are the condition for the
natural-law demand that international law be established for the
peaceful coexistence of those states. The natural law cannot make
its more distal demands known prior to the emergence of those
conditions under the aspect of which the natural law would
command.
La Soujeole amplifies this historical element in the law of
nations by drawing on the distinction between potency and act.
Prior to the emergence of certain civilizational circumstances
(e.g., the emergence of the modern nation-state), the demands of
the law of nations are in potency (e.g., that those nation-states
live peacefully by means of international law). La Soujeole
accordingly posits two avenues of development in the law of
nations. The first is the development of humankind’s knowledge
of the natural law (Maritain’s position); the second is the
development of culture that “permits an ‘actuation’ of natural
right” (Labourdette’s supplemental position).108 Such actuations
of natural law “only manifest themselves in certain existential
states of humankind, namely, certain states of civilization.”109
With the cultural development of humankind, some relations
between things change, and so what reason demands in light of
the nature of things changes. “Supposing humankind to be in this
state of organization,” Labourdette explains, “human nature
107

La Soujeole, “Insaisissable ‘jus gentium’?,” 301, quoting La justice, [12]: “décole
de la nature humaine mais à supposer un certain état, un ensemble de circonstances
historiques, en dehors desquelles la nature ne manifeste pas cette exigence parce qu’à vrai
dire le problème ne se pose pas.” This passage is not found in the recently published
version of Labourdette’s La justice, at least at the page cited by La Soujeole; it is taken
from the 1990 photocopy. The same example of nation-states being a necessary condition
for the emergence of modern international law occurs in M.-Michel Labourdette, O.P.,
“Jacques Maritain nous instruit encore,” Revue thomiste 87 (1987): 662.
108
La Soujeole, “Insaisissable ‘jus gentium’?,” 302.
109
Labourdette, “Jacques Maritain nous instruit encore,” 662: “certain exigences de
la nature (relevant donc du droit naturel) ne se manifestent que dans certains états
existentiels de l’humanité, en particulier, certains états de civilisation.”

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itself demands this or that conduct.”110 This makes culture, in La
Soujeole’s words, “a real, and not only noetic, principle of
actuation of circumstances grounded in nature.”111 In other
words, culture does not merely furnish conditions in which we
may better come to know the unchanging demands of the natural
law and of human dignity, but culture also creates conditions that
elicit new demands of the natural law which were only potential
prior to the cultural change. La Soujeole contrasts Labourdette
with Maritain on this point: “With Maritain, [Labourdette] has
no difficulty admitting the role of history in the knowledge of
natural right, but he goes further than his friend in admitting that
proper cultural development makes a part of the given of nature
pass from the virtual to the actual.”112
Indeed, Maritain does not address this possibility, for he limits
the work of new cultural circumstances to making a certain
“gnoseological” deduction from nature easier—but the deductions were always already morally possible apart from
changes in cultural or social circumstances. To use one of Maritain’s examples, the development of various agricultural means
gave humankind the noetic occasion to see how degrading slave
labor is precisely by making it less necessary to have slaves for
agriculture. Consequently humans could see more easily that
slavery is contrary to the dignity of man, and thereby commit to
its elimination. For Maritain, the advancement in the practice of
agriculture does not in such a case actualize a change in the
relation of things leading to a new deduction; it only enables the
recognition of what human dignity requires, which could and in

110

Ibid.: “A supposer l’humanité en cet état d’organisation, c’est la nature humaine
elle-même qui exige telle ou telle conduite.”
111
La Soujeole, “Insaisissable ‘jus gentium’?,” 302: “la culture aussi comme un principe
d’actuation réelle et non seulement noétique, de exigences fondées en nature.”
112
Ibid., 303: “Avec J. Maritain, il ne fit aucune difficulté pour admettre la rôle de
l’histoire dans la connaissance du droit naturel, mais il est allé plus loin que son ami en
admettant que la développement proprement culturel fasse passer du virtuel à l’actuel une
partie du donné de nature.”

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fact should have been realized long before.113 Maritain
emphasizes that he means not only slavery “in its absolute form”
but also in the other forms not condemned by medieval theologians.114 He applies to slavery the same primary-secondary
precept framework that Thomas applies to marriage and polygamy in the Sentences commentary. Absolute servitude is contrary to the primary precepts of the natural law, whereas “the
other more or less attenuated forms of servitude” are opposed to
the secondary precepts of the natural law. Yet even if these latter
are more capable of being tolerated than the former, this is no
argument against eliminating all servitude as “better states of
organization” emerge alongside “a better awareness of the dignity
of the human person.”115 The attenuated forms of servitude were
not as obviously contrary to the natural law as absolute servitude,
just as polygamy is not as obviously against the natural law’s
procreative precept as homosexual actions are. La Soujeole’s
point about Labourdette is that he embraces Maritain’s point
while adding that cultural development can effect an objective,
intrinsic change in the law of nations. Where Maritain would
assert that the attenuated forms of servitude were always contrary
to human dignity, but were only acknowledged as such when the
conditions were ripe for their elimination, Labourdette would say
that such attenuated forms of servitude were not contrary to
human dignity per se, but that once the conditions arose that
allowed for their elimination in favor of other labor arrangements better suited to the dignity of the human person, then their
elimination was morally obligatory.
Yves Simon similarly articulates a position that mediates
between the Salamancan and Neo-Thomist lines by positing an
intrinsic development in the law of nations through the conditions of culture and society. Simon agrees with Maritain that
moral conclusions strictly deduced from natural-law principles
113
Maritain, La loi naturelle ou loi non écrite, 869-71; see also Jacques Maritain, The
Rights of Man and Natural Law, trans. Doris C. Anson (New York: Charles Scribner’s
Sons, 1949), 105-11.
114
Maritain, Rights of Man and Natural Law, 105.
115
Ibid., 107-10.

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just are a part of the natural law by an “unqualified necessity.”116
His example is that lending at interest, apart from any
consideration of extrinsic titles and so on, is a violation of
commutative justice. Simon refers here to conclusions and
“antecedents,” that is, natural-law principles. Due to their logical
connection, conclusions will only be as necessary as their
antecedents. Yet there are “qualified antecedents” that involve
some condition, and the relation between the natural-law
conclusion and the natural-law premise will therefore be one of
conditioned necessity.
Simon identifies the “law of nations” with these conditioned
conclusions of the natural law, which are necessary but only
under some condition of society that demands such and such a
conclusion.117 Hence for Simon, the law of nations is composed
of “deductions from natural law which indeed involve contingent
conditions, but these contingent conditions are commonly
realized when societies are sufficiently developed.”118 Given that
these conditions which actualize the demands of the natural law
are common to social life, the law of nations will tend toward
universal observation across societies, but only supposing a
certain level of development. Private property as an institution,
for example, is only realized “within certain limits” and “under
common circumstances of civilized life.” In want of such
conditions, such as “in a very small tribe in a tropical forest,”
private property would not be a necessary obligation of the
natural law.119 Beyond the general conditioned conclusions of the
law of nations, someone cannot proceed logically to specific civil
laws. From the recognition of private property as a natural
institution under the requisite civilizational conditions, one
cannot logically deduce whether and what sort of inheritance tax
should exist. Simon warns, “do not try to obtain more precision,
116

Simon, Tradition of Natural Law, 150.
Ibid., 152. Delos similarly understands the ius gentium as “draw[ing from the
natural law’s first principles] indefinitely concrete applications, adapted to changing
historical circumstances” (Delos, La justice, 219).
118
Simon, Tradition of Natural Law, 152-53.
119
Ibid., 154.
117

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more specification, by way of logical connection. It will not
work.”120 Instead, this is the realm of the “prudential determination” of the lawgiver.121
In asserting the need for certain civilizational circumstances
for the law of nations to arise, Simon moves away from
Maritain’s doctrine that the earlier stages of moral development
represent mankind’s imperfect, confused knowledge of the
natural law’s implications.122 Simon grants such imperfect,
confused knowledge, but holds that earlier civilizational stages of
applying the natural law to social life lacked requisite conditions
for modern deductions regarding private property (e.g., an
Amazonian tribe). While essentially agreeing with Maritain that
the law of nations has a strictly logical connection to natural-law
principles, Simon is able to assert with the Salamancan line an
important role for the conditions of culture and society in
accounting for how the law of nations arises. To use an example
of the Salamancans, Simon can say that the enslavement of
prisoners of war was probably the best way to respect their
humanity in civilizational conditions where POW camps and
internationally enforced war conventions were not even
cognizable, let alone practicable—the alternative being slitting
the throat of every male capable of bearing arms. Simon and the
Salamancans seem to overlap, then, in requiring civilizational
progress in order for there to be a development in the law of
nations. Yet this alignment in attending to social conditions in
determining the law of nations should not obscure an essential
distinction. Simon still labels the connection between the natural-

120

Ibid.
Ibid.
122
To my knowledge, Maritain speaks similarly to Simon about civilizational
conditions in only one text: “The Law of Nations, or the common law of civilization,
deals, like natural law, with the rights and duties which follow from the first principle in
a necessary manner, but this time supposing certain conditions of fact, as for instance the
state of civil society or the relationships between peoples. It also, therefore, is universal,
at least in so far as these conditions of fact are universal data of civilized life” (Maritain,
Rights of Man and Natural Law, 70). This is so broad that even a Salamancan theologian
could agree. I am not aware of any other texts in Maritain on this point.
121

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law principles and the law of nations as a logical necessity, while
the Salamancans describe this connection as moral necessity
(necessity of the end). The Salamancans hold to the looser
necessity of the determinatio whereas even the Neo-Thomists
who recognize the conditional nature of the law of nations still
hold that it is composed essentially of conclusiones.
IV. EVALUATION
Both the Salamancan and the Neo-Thomist interpretations of
the ius gentium give an account of how the institutions necessary
for keeping the natural law develop in civilizational-moral time,
albeit in distinct ways. The Salamancan line emphasizes the
mutability of the ius gentium in itself, because it is a body of
institutions morally necessary for keeping the natural law in this
or that state of mankind or social circumstance. Personal
property, the inviolability of ambassadors, and the enslavement
of enemies taken in wartime are examples of such morally
necessary conventions and are not strict, logical deductions from
the natural law. Since there is nothing new under the sun, the
expectation is certainly that these institutions will be universally
observed and tend not to change in general. Some, however,
could and have changed, such as in the renunciation of the right
to enslave prisoners of war in a state of Christendom. According
to Maritain’s Neo-Thomist line, on the other hand, the ius
gentium does not change intrinsically but its gnoseological
element is clarified over time. Private property is a strictly
necessary deduction for keeping the natural-law doctrine of the
universal destination of goods. The approval of servitude of any
type was simply a confused, erroneous deduction from the
principles of the natural law. The law of nations will never
change in itself; only our awareness of it will. As we saw, some
adherents of this line, such as Labourdette and La Soujoule,
modify Maritain’s position by describing the law of nations as the
actualization of certain conditional precepts of the natural law by
changes in social circumstances, prior to which point such
commands of the natural law were merely potential precepts.

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Despite these essential differences, each line can accommodate
important features of the other so that on certain points they may
appear practically not to differ. For example, the Salamancan line
acknowledges Maritain’s insight that at any moment of
civilizational-moral time, a culture’s knowledge of the natural
law can be confused or imperfect. Accordingly, the moral sense
of the general person will not be sufficient for knowing the moral
law’s demands. Vitoria, for example, held that the wise must
instruct the people so that they know the more remote yet strictly
necessary precepts of the natural law. Vitoria called these the
“tertiary precepts” of the natural law, which include the
prohibition of fornication.123 This implies that a people will tend
toward failure in perceiving the requirements of the natural law
as the relation between the realities involved becomes more
complex, which offers more opportunities for the passions, sinful
habits, or depraved customs to interfere in the process of
deducing logically necessary but remote precepts. In either case,
both lines are familiar with Thomas’s observation regarding the
fragility of human knowledge of the natural law.124
Furthermore, when the Salamancan line posits a progression
in the law of nations under the influence of the Church, one detects a similarity with Maritain’s assertion that the knowledge of
the law of nations develops not only under civilizational conditions but also under the influence of the gospel. Yet the Salamancans do not adopt Maritain’s assumption that the historical
progression is always toward a more perfect awareness of the
moral law itself. Instead they speak more of the transition from
means permissible at one time to the adoption of superior means
for keeping the natural law.
Labourdette’s, La Soujoule’s, and to a lesser extent Simon’s
attention to the role of circumstances in the application of
123
Vitoria, Comentarios, IIaIIae.57.2 n. 4 (Beltrán de Heredia, ed., 3:9-10). Vitoria
calls these the “tertiary precepts” of the natural law. Presumably the prohibition of
fornication is “tertiary” because the prohibition of adultery—as one of the Ten
Commandments—is a secondary precept. Fornication violates the ends of matrimony, but
this is not as immediately evident as it is in the case of adultery.
124
STh I-II, q. 94, a. 4.

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BARRETT H. TURNER

natural-law principles to this or that cultural moment offers a
bridge between the Salamancan and Neo-Thomist lines. The
import of natural law to this or that situation could be one of
strict deduction (Neo-Thomist) or of a less strict, morally
necessary arrangement (Salamancan). Perhaps the ius gentium
can be spoken of loosely as a universally valid law which gains its
moral force by either mode of necessity. Vitoria himself speaks in
this way in his public lecture De indiis, presumably so as not to
alienate those holding to the viewpoint of the Roman jurists that
he elsewhere personally rejects: “the law of nations (ius gentium),
which either is or derives from natural law, as defined by the
jurist: ‘What natural reason has established among all nations is
called the law of nations.’”125 Even in their positive law interpretation, the Salamancans understand the ius gentium in the
main as practicably unchangeable, in part because of the usefulness of certain institutions and the fact that human nature lives in
the state of sin between the fall from grace and the Second
Coming.
On the other side, nothing prevents the Neo-Thomist line
from acknowledging a category of international positive law
morally necessary within and between nations for maintaining
peace. Maritain simply cannot call such a category the law of
nations, given his definition of the latter. As Labourdette and La
Soujeole note, the law of nations is itself prior to and the foundation for an international order of nation-states, the formation
of such an order being one of the conditional demands of the
natural law contingent on the actual existence of nation-states.
More significantly, Maritain cannot see such a body of inter125

De indiis 3.1, citing Institutes 1.2.1 (trans. in Vitoria, Political Writings, 278).
Vitoria has replaced homines in the Institutes with gentes. See also De temperantia 1.3.
Vitoria speaks this way primarily in his public releccios, which suggests that he was
speaking ambiguously for rhetorical purposes, knowing that there would be some in his
audience who held to the jurists’ conception of ius gentium. Indicating such a mixed
audience is Vitoria’s extensive apology in the introduction to De indiis for the theologian’s
competence over against civil lawyers in regard to the rights of the Amerindians. On the
other hand, Vitoria could speak his mind more directly when commenting on the Secunda
pars, for his students would have been more exclusively theologians.

IUS GENTIUM AS DEVELOPING MORAL LAW

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national law as possible prior to an international organization of
states, along the lines of a United Nations. He thus envisions that
modern nation-states will fulfill their obligations to the whole
world “not only by virtue of natural law and jus gentium, but also
by virtue of the positive laws which the politically organized
world society will establish and which its government will
enforce” (note the future tense).126 In contrast, the Salamancan
line does not understand universal positive law to require formal
political organization, since “[t]he whole world, which is in a
sense a commonwealth, has the power to enact laws which are
just and convenient to all men; and these make up the law of
nations.”127 For the Salamancans, there exists prior to any
international treaty or the formation of any organization an
international political unity and authority. A divergence
therefore remains between the Neo-Thomists and the Salamancans on whether the consent needed for such universal positive
law can be promulgated by reason through custom alone, or
whether a formal, international government is necessary to
obtain such consent, such as one would find with a United
Nations Organization.
The Neo-Thomist line, especially as articulated by Maritain,
gives a plausible harmonization of Thomas’s texts only if one
ignores what Thomas says about the institutions contained within
the law of nations. For all of Maritain’s strength in explaining
how changes in conditions afford human beings a better
epistemic viewpoint of the natural law’s demands, he leaves little
room for conditions themselves to activate what was only
potential in the natural law. That Labourdette, La Soujoule, and
Simon feel the need to round out Maritain’s theory by adding a
Salamancan-like emphasis on conditions and mutable institutions
in the law of nations indicates that Maritain’s position does not
fully capture the role of culture and history in the development
of morals. This is related to another weakness of Maritain’s
thought, namely, his identification of institutions as “strict
126
127

Maritain, Man and the State, 198.
Vitoria, De potestate civili, 3.4 (trans. in Vitoria, Political Writings, 40).

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conclusions from natural law” that are in fact only morally
necessary for keeping the natural law. Private property is one
example, but so is the humane treatment of prisoners of war.128
Remember that Maritain sees POW camps and the moral
rejection of slavery as changes in our knowledge of the natural
law (gnoseological element) rather than changes in the
conditioned application or extension of the natural law itself. Yet
nothing stops one from both rejoicing that POWs are no longer
enslaved, and also understanding that the enslavement of
prisoners of war was reasonable—even merciful—given the conditions of human societies in which such a practice emerged. The
enslavement of prisoners was an alternative to summarily
executing them. One could not simply allow the fighting men
among one’s enemies to go free after war, and one had a right to
exact retribution for the injustice and damages caused by an
unjust aggressor. It would appear that the custom was not merely
a matter of error on the gnoseological side of the ledger. Maritain
accordingly tends to read back into the natural law a modern
custom that is better at keeping the natural law and the dignity
of the human person as is possible only in modern conditions
(both in regard to awareness of human dignity and also the
existence of international treaties codifying and restricting the
rights of war better to keep international peace). The Salamancan
line identifies such customs as only “morally necessary” to keep
the natural law, and thus is more flexible in accommodating
diverse socio-political arrangements.
As insufficient as Maritain’s position is for explaining the
development of moral doctrine, including social doctrine, his
doctrine of the gnoseological element in the natural law must be
acknowledged by the Salamancan line in order to complete their
picture of the mutual interplay between social conditions and the
demands of the natural law. A change in conditions that leads to
a reconfiguration of the law of nations may also be an opportunity for seeing something as a new extension of the natural law
under said changed circumstances. To attain an adequate
128

Maritain, La loi naturelle ou loi non écrite, 735.

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391

grounding for a theology of the development of moral doctrine,
either one must add to the Salamancan line a Maritain-like
account of conditions changing our knowledge of what is possible
in the natural law, resulting in new possibilities in the law of
nations; or one must modify Maritain—as Labourdette and La
Soujoule do—by adding the power of new conditions to activate
what was potential in the natural law itself (and not merely in our
gnoseological awareness). These two lines so modified practically
converge in being capable of presenting an interplay between new
conditions and new extensions of the natural law that elicit
developments in social doctrine, without prejudice to the human
institutions and magisterial teaching that were necessary for past
configurations of human society.
CONCLUSION
Either the Salamancan or Labourdette’s version of the NeoThomist interpretation of ius gentium permits an explanation of
how the natural law and its applications can develop on account
of changing socio-political conditions. With new conditions
come new possible applications or extensions of the natural
law—perhaps hitherto unarticulated because unthinkable or
impracticable—and therefore the possibility of new customs or
institutions that are better ways of keeping the natural law being
adopted by the nations. Accordingly, the Thomistic concept of
the law of nations can ground an account of how the Church’s
interpretation of the natural law and its application can likewise
develop in response to changes in social conditions. Hence this
fruitful debate between the Salamancan and Neo-Thomist lines
suggests ways for philosophers and theologians to speak more
precisely about how changing socio-political conditions can lead
to changes in how the natural law is applied, extended, and
promoted in this or that state of civilization.
With the modification of Maritain by Labourdette and others,
the debate has come full circle to the Salamancan insistence on
the conditional nature of the law of nations. Much has been
gained on the way, namely, a progressive sense of the interplay

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between changing conditions and human institutions and the
possibility of unlocking, as it were, new extensions and precisions
in natural law itself. The concept of the law of nations therefore
gives to modern theologians a way to speak about how certain
moral and legal standards can develop, without implying that the
natural law or human nature is mutable or unknowable in its
essential structure. This potential of the law of nations concept
for grounding a theology of the development of moral doctrine
fits well with Johannes Messner’s description of the relevance of
ius gentium in the modern world:
The reason why the earlier traditional natural law school [i.e., the Salamancan
line] classed ius gentium so decidedly under positive law as distinct from natural
law lies in the intention of the school to stress the variability of ius gentium. In
this, in spite of its essentially static views of society, it kept the door open for
the understanding of the dynamic development of mankind’s sense of law and
for the expression of this development in a progressive common human law.129
The generally recognized principles of law today, by contrast with earlier times,
include freedom of conscience, of religious practice, of speech, of association,
and also include the principles, realized in social legislation, which guarantee a
certain minimum of protection of human labor. Since the content of these
principles represents the natural juridical consciousness of peoples at the present
stage of their development, it forms present-day ius gentium. This reference to
a ius gentium of today is intended, on the one hand to draw attention to the
essentially progressive character of ius gentium and, on the other hand, to the
evolutionary impulse which it transmits to the legal consciousness.130

The potential for “dynamic development” in the law of nations
can also help the theologian explain the pathways of
development in the Catholic Church’s social doctrine. So long as
we are speaking of moral objects that are conditioned on a certain
state of civilization or are only morally necessary for keeping the
natural law, what was permitted can become impermissible, and
what was not morally required can become so.

129
Johannes Messner, Social Ethics: Natural Law in the Western World, 2d ed., trans.
J. J. Doherty (St. Louis: Herder, 1965), 281.
130
Ibid., 283.

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393

The two lines of this Thomistic debate overlap in holding that,
while the natural law never changes intrinsically, a change in
social realities results in a change in what the natural law itself
demands or in what customs or institutions are necessary for
keeping the natural law. The two lines, however, display unequal
potential for discussing the development of Catholic doctrine.
Maritain’s account, at least, suffers from a tendency to see even
the moral teaching of the Church as often captive to erroneous
deductions from the natural law, and therefore as unreliable or
uncertain. The Salamancan line and Labourdette’s version of the
Neo-Thomist are consonant with Avery Dulles’s insistence that
much of the development of Catholic social doctrine hinges on
applications of the natural law in light of civilizational conditions,
not changes in doctrinal principles themselves. In sum, the
Thomist concept of the law of nations suggests a starting point
for explaining past development of moral doctrine and for
anticipating future development. Such a theory can be advanced
without calling into question the immutability of the natural law
in itself, and the authority and general reliability of the
Magisterium even in interpreting the moral law in a nondefinitive way, for the development of moral doctrine can only
derive from the natural and divine law and, upon pain of cutting
off one’s own root, can never contradict it.131

131

My thanks to Joshua Hochschild, John Meinert, Greg Murry, Joshua Brown,
Francis Feingold, and the anonymous peer reviewers of The Thomist for their helpful
criticisms of earlier drafts.

The Thomist 84 (2020): 395-434

THE ROLE OF NATURAL PHILOSOPHY IN THE
BEGINNING OF METAPHYSICS
GLEN COUGHLIN
Thomas Aquinas College
Santa Paula, California

T

HIS ESSAY concerns an issue controverted in Thomistic
circles, namely, whether one must prove the existence of
immaterial beings in natural philosophy before one can
begin the scientific study of metaphysics. By “metaphysics,” I
mean a science1 of being just as being (ens commune or ens
inquantum ens)2 and not as restricted to some determinate sort
1

Here the context is Aristotelian and Thomistic science, not modern experimental
science or its adumbrations. This meaning of “science” is that of the Posterior Analytics,
not that of Bacon or Newton or Einstein. See Aristotle, Posterior Analytics 1.2-6.71a175a37 (Aristotle’s Prior and Posterior Analytics, A Revised Text with Introduction and
Commentary, W. D. Ross [Oxford, 1949]); see also St. Thomas Aquinas, I Post. Anal.,
lect. 4-14 (Sancti Thomae Aquinatis doctoris angelici Opera omnia iussu Leonis XIII,
P.M. edita, cura et studio Fratrum Praedicatorum [Rome and Paris: Leonine
Commission, 1989], 1/2:18-25 [Marietti ed., 28-126]). (I shall cite the Leonine editions
for those works of St. Thomas which are available in that edition. I shall also include a
reference to the Marietti edition paragraph numbers when this would be helpful. All
translations are my own unless otherwise noted.) For further discussion of the
differences between these two “sciences”, see Glen Coughlin, “Introduction” and
“Appendix 1” in Physics, Or Natural Hearing, trans. and ed. Glen Coughlin (South
Bend, Ind.: St. Augustine’s Press, 2005), ix-xx, 206-22.
2
Super Boet. De Trin., q. 5, a. 1 (Leonine ed., 50:138, ll. 154-56): “There are certain
things we can speculate about which do not depend on matter according to their
existence [esse], because they are able to be without material, whether they never be in
material, like God and angel, or in certain cases they are in material and in certain ones
not, like substance, quality, being [ens], potency, act, one and many, and such things,
about all of which is theology, that is, divine science, because the principal thing among
those known in them is God. Which (science) is called by another name, ‘metaphysics,’
that is, ‘beyond physical (science),’ because to us, for whom it is necessary to arrive at
395

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GLEN COUGHLIN

of being, such as quantified or mobile being, the subjects
respectively of mathematics and natural philosophy.3 Being as
such includes immaterial beings, such as separate intelligences
and intellectual souls, as well as material beings, such as plants
and animals.4 All Thomists hold that such immaterial things
exist. But do we have to know that they exist before we begin
the science of being as such? And, if so, how do we go about
learning that they exist?5 My claim is the traditional one,6 that
we do have to know of the existence of immaterial beings to
begin the scientific study of metaphysics, and that we learn of
their existence through natural philosophy.7

the nonsensible from the sensible, learning it occurs after physical [science].” See also
Metaphys., pro. (St. Thomas Aquinas, In duodecim libros Metaphysicorum Aristotelis
expositio, ed. M.-R. Cathala, O.P., and R. M. Spiazzi, O.P. [Turin and Rome: Marietti,
1950], 1-2).
3
In Boet. De Trin., q. 5, a. 3, ad 6 (Leonine ed., 50:141, ll. 322-37). See also VI
Metaphys., lect. 1 (Marietti ed., 1147).
4
In Boet. De Trin., q. 5, a. 4, ad 6 (Leonine ed., 50:156, ll. 314-19): “To the sixth it
is to be said that metaphysics considers singular beings, not according to their proper
notions, through which they are such or such a being [ens], but according as they share
the common notion of being; and thus even matter and motion belong to its consideration.” See also XI Metaphys., lect. 1 (Marietti ed., 2159): “this science determines
[the truth] about sensible substances insofar as they are substances, not insofar as they
are sensible and mobile. For this properly belongs to natural [science]. But the proper
consideration of this science is about substances, which are not ideas, nor separated
mathematical [things], but first movers, as will be clear below.”
5
I here take it for granted that metaphysics is primarily about a sort of extramental
being. Metaphysics also studies the order of the sciences, the axioms, and so on, but
these are not its primary interest, and so, even if one might say, in the absence of a
proof that there are immaterial things, that metaphysics could be pursued because these
sorts of questions can be, this would not address the primary interest of the
metaphysician. On the various matters treated by metaphysics, see Duane Berquist, “The
Matter and Order of Wisdom,” in Philosophia perennis 3, no. 2 (Fall 1996): 3-64
(available at http://at-studies.com/files/5314/2678/3485/The_Matter_and_Order_of_
Wisdom.pdf).
6
John Wippel, “Metaphysics and separatio,” in Metaphysical Themes in Thomas
Aquinas (Washington, D.C.: The Catholic University of America Press, 1984), 90, 104
n. 87.
7
I would like to thank John Baer and Travis Cooper, as well as the two anonymous
reviewers of The Thomist, for their helpful suggestions about this essay.

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397

I. GENERALIZATION
We might think we can bypass the problem of proving the
existence of the immaterial and go directly to metaphysics. If
metaphysics is about being in common or being as being, one
might think that there can be a science of metaphysics simply
because we have the universal name “being,” and especially
because St. Thomas Aquinas and Aristotle say that in pursuing a
science we should start with what is more general.8 It seems that
metaphysics is not only possible right away, but ought to be the
very first philosophy we study, perhaps after logic. “Being” certainly does seem to name something more universal than
“mobile being,” the subject of natural philosophy, for the
adjective “mobile” qualifies and limits the noun “being.” But
there are problems with this simple position.
A new science demands a new mode of definition, and mere
generality does not suffice. The discussion of figures, though
more general than the discussion of triangles, does not belong
to some more universal science of mathematics. The division of
the speculative sciences, according to St. Thomas, is based not
upon generality, but upon the degrees of materiality found in
the definitions of the subject-genera of the sciences.9 The reason
for this is that every habit (and science is a habit of knowing
something by way of a syllogism)10 is defined in terms of its

8
Aristotle, Physics 1.1.184a10-b14 (Aristotle’s Physics, Sir David Ross [Oxford,
1936]); cf. Aquinas, I Phys., lect. 1 in toto (Leonine ed., 3:3-6).
9
I Post. Anal., lect. 15 (Leonine ed., 1/2:57, ll. 43-66; 58, ll. 102-39 [Marietti ed.,
130, 132]); lect. 41 (Leonine ed., 1/2:154-55, ll. 242-300 [Marietti ed., 366-67]);
lect. 43 (Leonine ed., 1/2:165, ll. 281-96 [Marietti ed., 393]); In Boet De Trin., q. 5, a.
1 (Leonine ed., 50:138, ll. 113-40); VI Metaphys., lect. 1 (Marietti ed., 1156-58, 116063); II Phys., lect. 3 (Leonine ed., 3:62-63 [Marietti ed., 159-65); lect. 1 (Leonine ed.,
3:88 [Marietti ed., 243]); III Sent., d. 14, a. 3, qcla. 4, ad 2 (Scriptum super Sententiis
Magistri Petri Lombardi, vols. I-II, ed. P. Mandonnet [Paris, 1929]; vols. III-IV, ed. R. P.
Moos [Paris, 1933, 1947]; 3:460); STh I, q. 1, a. 1, ad 2 (Leonine ed., 4:7).
10
I Post. Anal., lect. 4 (Leonine ed., 1/2:20, ll. 140-53 [Marietti ed., 36]).

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object.11 But the objects of science are things insofar as they are
intelligible. Because intelligibility is due to removal from
matter,12 the object of every speculative science is something
removed from matter, and the kinds of intelligibility (and so the
species of science) are determined by the kinds of removal.13
The ways in which the sciences differ per se, then, is by the
presence or absence of matter in their subject-genera. Some
things have sensible matter in their definitions, like natural
things (e.g., horses and dogs, rocks and fires, cannot be or be
understood without reference to sensible qualities like color,
weight, hardness, etc.); others do not, but only have “intelligible
matter.” Squares and rectangles, being accidents, cannot exist
apart from a substance in which they inhere. That substance is
then a sort of matter, but it is perceivable only by the intellect,
and so is called “intelligible matter.”14 Things defined with
sensible matter are studied by natural philosophy, those
without, but with intelligible matter, by mathematics. Those
things without any matter in their definition at all (e.g., being,
one, and separate substances), are studied by metaphysics.15
Here things become a little more complicated because St.
Thomas gives more than one description of the science of metaphysics. Sometimes he says it concerns being as being,
sometimes the first causes, sometimes the immaterial. How can
it be about all three of these? It is not about all of them as
11
I Post. Anal., lect. 41 (Leonine ed., 1/2:154-55, ll. 242-300 [Marietti ed., 36667]); STh I-II, q. 54, a. 2 (Leonine ed., 6:342-43); III Sent., d. 33, q. 1, a. 1, qcla. 1
(Moos, ed., 3:1018-20).
12
STh I, q. 14, a. 1 (Leonine ed., 4:166); III De Anima, lect. 7 (Leonine ed.,
45:203-4 [Marietti ed., 677-80]); ScG I, c. 45 (Leonine ed., 13:136).
13
See the references in note 9.
14
See In Boet. De Trin., q. 5, a. 1 (Leonine ed., 50:138, ll. 149-54); q. 5, a. 3
(Leonine ed., 50:149, ll. 270-74). For further discussion of intelligible matter, see Paul
O’Reilly, “What Is Intelligible Matter?”, The Thomist 53 (1989): 74-90; AugustinGabriel, “Matière intelligible et mathématique (I),” Laval théologique et philosophique
172 (1961): 173-96; idem, “Matière intelligible et mathématique (II),” Laval
théologique et philosophique 182 (1962): 177-210.
15
In Boet. De Trin., q. 5 passim (Leonine ed., 50:136-56), especially the bodies of
the four articles; II Phys., lect. 3, in toto (Leonine ed., 3:61-63); VI Metaphys., lect. 1
(Marietti ed., 1156-65); II Post. Anal., lect. 9 (Leonine ed., 1/2:206-7, ll. 71-86
[Marietti ed., 494]).

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399

subjects, though it is in a sense about all of them. It is about
being as being in the sense of a subject-genus, that is, what the
science seeks to understand. It is about the first causes because
the first causes of all are the causes of being as such, and every
science looks for the principles and causes of its subject. It is
about immaterial beings because (as we eventually discover) the
first causes are, in fact, immaterial beings.16
The simple fact that the name “being” is general, then, does
not establish a new science; we must insist that a new science
have a new mode of definition, one differing from those of
natural philosophy and mathematics with regard to the presence
or absence of matter in the definition. We may depend upon
our mere experience to recognize the existence of the subjectgenus of natural philosophy, but naming that same sort of thing
with a more general name, unless that name is involved with
some more extreme removal from matter, will not bring us any
closer to metaphysics. We must start our metaphysics, then,
with definitions that separate from all matter. How might we
establish that possibility, and so the possibility of metaphysics?
Most obviously, by discovering the actual existence of purely
immaterial beings. We will here, however, consider positions
that question the necessity of that approach.
In general, there are only two roads to the truth: direct
experience and thought. The latter can be divided into three
ways or acts: seizing the whatness of a thing, forming a
statement or judgment about a thing, and forming an
argument.17 In what follows, we will examine whether any of
these can lead us to a knowledge of the immaterial.
16
Metaphys., pro.; see also In Boet De Trin., q. 5, a. 4 (Leonine ed., 50:154, ll.
175-206).
17
Post. Anal., pro. (Leonine ed., 1/2:4-5:32-50). Cf. In Boet. De Trin., q. 5, a. 3
(Leonine ed., 50:147, ll. 89-95), where St. Thomas distinguishes only two acts of the
mind, seizing the whatness and forming a judgment. Why he here distinguishes only
these two ways is beyond the scope of this paper, but it is clear enough that an argument
is not a mere statement. It is noteworthy, however, that by making the division in the
De Trinitate commentary into two instead of into three, he leaves open the possibility

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II. DISCOVERING IMMATERIAL REALITIES
A) By Experience
I take it for granted that most men do not have direct
experience of immaterial natures such as angels and God. One
might more plausibly say we have direct experience of the
immateriality of our intellects, though even this is far-fetched.
Saint Augustine himself said that for years he could not conceive
of anything except as a body, including, presumably, his own
intellect.18 This might be expected, because all our knowledge
takes its origin in sensation, and so we may easily remain at the
level of sensation, never realizing that there are nonmaterial
things.19 And St. Thomas spends significant time proving that
the intellect is immaterial—an odd undertaking if this is
apparent from experience.20 Direct experience, then, is not a
road to knowledge of the immaterial.21
B) By the First Act of the Intellect
The second possible route to seeing that there are immaterial
realities is that of Avempace.22 Saint Thomas reports that
Avempace held that one could abstract from material things the
essences of immaterial things:
For since our intellect is naturally apt to abstract the quiddity of a material
thing from material, if in that quiddity there is again something material, it

that the separation associated with metaphysics is a result of argument, perhaps even in
natural philosophy.
18
Confessions 5.10.19.
19
See, e.g., STh I, q. 44, a. 2 (Leonine ed., 4:457-58); q. 75, a. 1 (Leonine ed.,
5:194-95).
20
See STh I, q. 75, a. 2 (Leonine ed., 5:196-97); III De Anima, lect. 7 (Leonine ed.,
45:203-4 [Marietti ed., 677-85]); lect. 10 (Leonine ed., 45:219-20, ll. 64-86 [Marietti
ed., 732-33]); ScG II, cc. 49-51 (Leonine ed., 13:381-86); Q. D. De Anima, aa. 1-2
(Leonine ed., 24/1:3-21).
21
See Therese Scarpelli Cory, Aquinas on Human Self-Knowledge (Cambridge:
Cambridge University Press, 2014), 57, 177-85.
22
This is a Latinized form of his Arabic name, Ibn Bajjah (1095-1138/9).

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401

will be able to abstract again, and since this cannot go on to infinity, at length
it will be able to arrive at understanding some quiddity which is wholly
without matter. And this is to understand immaterial substance.23

We might compare this view to what occurs in mathematics. We
can remove sensible matter from our notion of, say, a triangle,
and if we find our triangle still sullied with the sensible we can
purge it further until we get a purely quantitative object. Why
can’t we arrive at an immaterial conception of being in the same
way?
One might argue that this process, if it could occur, would
only show us what immaterial things are, not that they are
possible as real existent beings. But this response misses a
fundamental point. If we really could abstract such an essence,
it would by that fact be known to be possible, for it would exist
in the thing from which we were abstracting it. It would be like
the abstraction of any other universal. Just as we draw the
notion “plant” from the particular plants we see around us, and
so know that the nature “plant” is possible, so would we
abstract this supposed immaterial essence and thereby know it
to be possible. The very fact that we could abstract it from what
is before us would prove that it is in what is before us and so
would prove that it is a real possibility. Thus, the grasp of such
an immaterial being would be sufficient to ground a new
science.
Saint Thomas’s critique of this view is devastating. The following text follows immediately upon the text quoted above:
This would be said efficaciously, if immaterial substances were the forms and
species of these material things, as the Platonists posit. But if we do not posit
this, but suppose that immaterial substances are of a wholly other notion from
23

STh I, q. 88, a. 2 (Leonine ed., 5:367): “Cum enim intellectus noster natus sit
abstrahere quidditatem rei materialis a materia, si iterum in illa quidditate sit aliquid
materiae, poterit iterato abstrahere, et cum hoc in infinitum non procedat, tandem
pervenire poterit ad intelligendum aliquam quidditatem quae sit omnino sine materia. Et
hoc est intelligere substantiam immaterialem.” See also In Boet. De Trin., q. 6, a. 4
(Leonine ed., 50:170-71, ll. 123-53).

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the quiddities of material things, however much our intellect might abstract
the quiddity of a material thing from matter, it would never arrive at
something similar to immaterial substance. And therefore we are not able to
understand immaterial substances perfectly through material substances.24

We cannot abstract the quiddity of an immaterial thing from a
material thing for the very simple reason that it is not in the
material thing to begin with. If immaterial things are of a wholly
other notion (ratio) than material ones, then the notions we get
from material things will never be the same as the notions of
immaterial things. Since abstraction is only the drawing of one
aspect of a thing away from another,25 we cannot arrive at the
notions of immaterial things from material things by way of
abstraction. One cannot get blood from a turnip and one cannot
get an angel from a potato—it’s just not in there. This is exactly
why St. Thomas says that Avempace’s notion of simple
abstraction being a road to the knowledge of immaterial things
is an error.
The upshot is that immaterial things are so profoundly
different from material things that we cannot divine what they
are merely by noting something inherent in material things. The
names we use of immaterial things and of material ones, like
being, one, potency, act, and so on, are not univocal, but
analogous. As St. Thomas says elsewhere: “quiddity and all such

24

Ibid.: “Quod quidem efficaciter diceretur, si substantiae immateriales essent
formae et species horum materialium, ut Platonici posuerunt. Hoc autem non posito,
sed supposito quod substantiae immateriales sint omnino alterius rationis a quidditatibus
materialium rerum; quantumcumque intellectus noster abstrahat quidditatem rei
materialis a materia, nunquam perveniet ad aliquid simile substantiae immateriali. Et
ideo per substantias materiales non possumus perfecte substantias immateriales
intelligere.” See also Q. D. De Anima, a. 16 (Leonine ed., 24/1:145, ll. 292-98): “But
this argument is wholly insufficient. First, indeed, because the quiddities of material
things are of another genus from the separated quiddities, and they have another mode
of existing [alium modum essendi]. Whence, from this, that our intellect understands the
quiddities of material things, it does not follow that it can understand separated
quiddities.”
25
See esp. In Boet. De Trin., q. 5, a. 3 (Leonine ed., 50:148, ll. 159-79); STh I, q. 84,
aa. 6-7 (Leonine ed., 5:323-26); q. 85, a. 1 (Leonine ed., 5:330-32).

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403

names are said in a way equivocally of sensible things and of
those [i.e., immaterial] substances.”26
C) By the Second Act of the Intellect
If the first act of the intellect, abstraction of a nature, cannot
get us to metaphysics, perhaps the second act, judgment, can.
Some grounds for this position are purportedly found in the
following statements:
It is to be known, therefore, that, according to the Philosopher, in the third
book of De anima, the operation of the intellect is twofold: one, which is
called the “understanding of indivisibles,” by which it knows, about each
thing, what it is; the other, by which it composes and divides, namely, by
forming affirmative or negative statements. And these two operations indeed
correspond to two which are in things. The first operation looks to [respicit]
the very nature of a thing, according to which the thing understood obtains
some level [gradus] among beings, whether it be a complete thing, like some
whole, or an incomplete thing, like a part or an accident. The second
operation looks to [respicit] the very existence [esse] of the thing, which
certainly results from the bringing together of the principles of the thing in

26

In Boet. De Trin. q. 6, a. 3 (Leonine ed., 50:167, ll. 80-82): “quiditas et omnia
huiusmodi nomina fere equiuoce dicantur de sensibilibus et de illis substantiis.” See also
IV Sent., d. 49, q. 2, a. 7, ad 12 (Sancti Thomae Aquinatis Opera omnia [Parma: Typis
Petri Fiaccadori, 1858], 7/2:1213): “speculative sciences proceed from self-evident
principles which are taken from sense, as is said in Posterior Analytics II; and therefore,
through them we are not able to arrive at the essences of those things which exceed all
sensible forms; whence, through no speculative science which we acquire at present do
we know what God is, or what an angel is, except under certain likenesses, knowing
more about them what they are not than what they are; and because of this the
Philosopher says in the beginning of the Metaphysics that science about God is not a
human possession, because, indeed, we are not able to have it to the full.” See also ScG
III, c. 41 (Leonine ed., 14:102-4). The first text cited in this note speaks of
equivocation. It is clear, however, that St. Thomas cannot mean pure equivocation, but
rather analogy. In some texts, he includes analogical names under equivocal names (STh
I, q. 13, a. 10, ad 4 [Leonine ed., 4:161]); in others, he contrasts analogical names and
equivocal names (I Sent., d. 25, q. 1, a. 2 [Mandonnet, ed., 1:607]), sometimes giving
the latter a more precise name, “pure equivocals” or “equivocals by chance” (STh I,
q. 13, a. 5 [Leonine ed., 4:146-47]; ScG I, cc. 33-34 [Leonine ed., 13:102-4]).

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composites or goes along with the simple nature itself of the thing, as in
simple substances.27

Later in the same article, St. Thomas adds,
In those things, however, which are able to be divided according to existence,
separation is found rather than abstraction. . . . Substance, however, which is
the intelligible material of quantity, is able to be without quantity, so that to
consider substance without quantity belongs to the genus of separation more
than to that of abstraction. Thus, therefore, a threefold distinction is found in
the operation of the intellect. One according to the operation of the intellect
of composing and dividing, which is properly called “separation,” and this
befits the divine science or metaphysics.28
27

In Boet. De Trin., q. 5, a. 3 (Leonine ed., 50:147, ll. 89-105): “Sciendum est igitur
quod secundum Philosophum in III De anima duplex est operatio intellectus: una, que
dicitur intelligentia indiuisibilium, qua cognoscit de unoquoque quid est, alia uero qua
componit et diuidit, scilicet enuntiationem affirmatiuam uel negatiuam formando. Et
hee quidem due operationes duobus que sunt in rebus respondent. Prima quidem
operatio respicit ipsam naturam rei, secundum quam res intellecta aliquem gradum in
entibus obtinet, siue sit res completa, ut totum aliquod, siue res incompleta, ut pars uel
accidens. Secunda uero operatio respicit ipsum esse rei; quod quidem resultat ex
congregatione principiorum rei in compositis, uel ipsam simplicem naturam rei
concomitatur, ut in substantiis simplicibus.” See also I Sent., d. 19, q. 5, a. 1, ad 7
(Mandonnet, ed., 1:489); I Sent., d. 38, q. 1, a. 3 (Mandonnet, ed., 1:903). Whether
the claims that the text indicates the path to knowing real existence, that this is the
ground for Thomistic metaphysics, and that it indicates, in addition, a glaring difference
between Aristotelian and Thomistic metaphysics, are issues beyond this article. I limit
myself to asking whether knowledge of the subject-genus of metaphysics demands
knowledge of the existence of immaterial beings, and whether such knowledge is gained
in natural philosophy. Among those who accept the text as indicating an act of
judgment unmediated by natural philosophy as the gateway to metaphysics are Etienne
Gilson, Being and Some Philosophers (2d ed.; Toronto: Pontifical Institute of Mediaeval
Studies, 1952), 201-7; Jacques Maritain, Existence and the Existent, trans. Louis
Galantiere and Gerald B. Phelan (New York: Image, 1956), 25-44; Joseph Owens, An
Elementary Christian Metaphysics (Houston: Center for Thomistic Studies, 1985), 9697; idem, “Metaphysical Separation in Aquinas,” Mediaeval Studies 34 (1972): 302-3;
John Wippel, The Metaphysical Thought of Thomas Aquinas: From Finite Being to
Uncreated Being (Washington, D.C., The Catholic University of America Press, 2000),
60-61; idem, “Metaphysics and separatio,” 69, 102-4; John Knasas, Being and Some
Twentieth-Century Thomists (New York: Fordham University Press, 2003), 69-70;
idem, The Preface to Thomistic Metaphysics: A Contribution to the Neo-Thomist Debate
on the Start of Metaphysics (New York, Peter Lang, 1990), 71-72, 74.
28
In Boet. De Trin., q. 5, a. 3 (Leonine ed., 50:149, ll. 256-58, 270-79): “In his
autem que secundum esse possunt esse diuisa magis habet locum separatio quam

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405

Separation (i.e., negative judgment) differs from abstraction in
that it looks to the existence of things and is therefore found in
things which are actually separated in reality; abstraction,
properly speaking, draws away from each other different
aspects of a being at least one of which does not depend on the
other for its intelligibility, even if they are found together in
reality.29 Those, therefore, who say that essence is attained by
abstraction and existence by judgment claim that being in
common is attained by recognizing both these distinctive
contents and, by way of the judgment “it is,” their union in the
existent things around us:
First, the knowing subject apprehends what the given object is, next it judges
that the object is, and this instantaneous recomposition of the existence of
given objects with their essences merely acknowledges the actual structure of
these objects. The only difference is that, instead of being simply experienced,
such objects now are intellectually known.30

The question arises, supposing we grant all of this, is the grasp
of being which we have at this early stage of thought sufficient
for beginning metaphysics?
On this point there is disagreement among those who follow
this view so far. Jacques Maritain, for his part, seems to think

abstractio. . . . Substantia autem, que est materia intelligibilis quantitatis, potest esse sine
quantitate; unde considerare substantiam sine quantitate magis pertinet ad genus
separationis quam abstractionis. Sic ergo in operatione intellectus triplex distinctio
invenitur: una secundum operationem intellectus componentis et diuidentis, que
separatio dicitur proprie, et hec competit scientiae diuinae siue metaphisice.”
29
In Boet. De Trin., q. 5, a. 3 (Leonine ed., 50:148, ll. 159-75). Saint Thomas
nowhere explicitly says—in texts in which he is indisputably speaking in his own voice
rather than as a commentator—how the separation characteristic of metaphysics is
possible. I maintain that the separation is the result of an argument proving the
existence of a positively immaterial being, that is, something which can subsist without
matter.
30
Gilson, Being and Some Philosophers, 204. I will not here question the Gilsonian
reading of the text of In Boet. De Trin., q. 5, a. 3. However, granting it for the sake of
argument, I will dispute the consequences drawn from it.

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that in the original grasp of ens we can already see that ens need
not be material. As he puts it:
Such objects [i.e., transcendentals, such as being, one, etc.] are trans-sensible.
For though they are realized in the sensible in which we first grasp them, they
are offered to the mind as transcending every genus and every category, and as
able to be realized in subjects of a wholly other essence than those in which
they are apprehended. It is extremely remarkable that being, the first object
attained by our mind in things—which cannot deceive us since being the first,
it cannot involve any construction effected by the mind nor, therefore, the
possibility of faulty composition—bears within itself the sign that beings of
another order than the sensible are thinkable and possible.31

Maritain immediately adds that this is only the recognition of a
possibility, that we would need to have some “reasoning from
the data actually given to us in sensible existence” in order to
know that there are in fact such immaterial things.32
Nevertheless, for Maritain the full latitude of the possibilities of
being is immediately established and we are set to begin
metaphysics.33
But the same objection presents itself, namely, that the immaterial and the material do not share any character univocally.
It cannot be, then, that the mere judgment that a material thing
exists makes clear the reality or even the possibility of the
existence of an immaterial thing, for that judgment, if true, only
unfolds what is present in the material being in front of us.
There are two possible understandings of Maritain’s view.
Either the notion of being that we obtain at the beginning of
intellectual awareness or through the “intuition of being” is one
single univocal notion appropriate for the immaterial as well as
the material, or it is not univocal but nevertheless contains
actually, and not by inferential implication, the concepts both of
31
Jacques Maritain, The Degrees of Knowledge, trans. Gerard B. Phelan (New York:
Charles Scribner’s Sons, 1959), 214.
32
Ibid.
33
In Existence and the Existent, Maritain says the ground of metaphysics is an
“intuition of being,” which he distinguishes from the “vague being of common sense.”
Still, the description he gives of this intuition does not imply that the grasp of being
which the metaphysician cherishes is had by anything other than a direct, unmediated
judgment. See Existence and the Existent, 28-31.

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the material and of the immaterial. Neither is possible. We have
already argued that there is no notion of material being appropriate to immaterial being because these are omnino altera.
Nor can any notion other than that of material being be
obtained from material being, for there is in fact no other sort
of being or existence latent within it.
Maritain’s caveat, that he means only to say that we see the
possibility, not the actual reality, of the various sorts of being
from our initial encounter with being, is of no avail. Freeing the
notion of being from any particular material essence (or even
from many such essences) does not permit us to say it is even
possible that it be freed from every material essence. The fact
that being is not the same as the being of a dog does not imply
that angels (or, for that matter, horses) can exist.
Another view, akin but more subtle, is subject to similar
criticism. John Wippel objects to the claim that metaphysics
must wait upon another science, natural philosophy, to prove
the existence of positively immaterial being (i.e., beings that are
without matter, such as God or angels) before inquiring into its
own subject. That subject is ens commune or being as being,
which Wippel calls negatively immaterial being, that is, being
understood as open to immaterial and material being.34 Both
positively and negatively immaterial being are treated by metaphysics, but not in the same way. The subject of metaphysics is
ens commune; positively immaterial being is treated as the cause
of that subject-genus.35 Because it is the cause of being as being,
Wippel argues, if we need to prove that positively immaterial
being exists before we even begin metaphysics, we seem to be
saying that we need to have uncovered the cause of being as
34
Wippel, Metaphysical Thought, 9, 17, 52-53. These expressions come from
Wippel, not St. Thomas, but they seem accurately to reflect a distinction St. Thomas
makes himself. See In Boet. De Trin., q. 5, a. 1 (Leonine ed., 50:138, ll. 154-60); XI
Metaphys., lect. 1 (Marietti ed., 2146).
35
Saint Thomas cannot mean that every positively immaterial thing is a cause of
being, for he thinks only one of them, God, is such a cause. See ScG II, c. 15 (Leonine
ed., 13:294-95).

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being before we have even started pursuing the science which is
charged with that very task.36 Wippel suggests, then, that there
must be some other way to start. That way involves separatio,
which St. Thomas identifies as the mode of removal from
matter peculiar to the science of metaphysics.37
In particular, it seems that Wippel wishes to appeal to the
separability of substance, which is the primary sort of being,38 in
order to ground metaphysics. He cites the following text:
“Substance, however, which is the intelligible matter of
quantity, is able to be without quantity; whence to consider
substance without quantity belongs more to the genus of
separation than of abstraction.”39 This passage occurs in the
midst of a discussion of the order in which accidents arise in a
substance. Just as sensible qualities like hot and red presuppose
quantity, whereas quantity can be defined without sensible
qualities, so quantity presupposes substance, though substance
can be defined without quantity; such a notion of substance is
only negatively immaterial. But unlike quantity, which even if
defined without sensible qualities cannot actually be without
them, substance can actually be without quantity, and thus
without matter.40 Things which can exist apart are removed
from each other in the mind by separatio, not by abstractio:
“according to the operation by which we compose and divide,

36

Wippel, Metaphysical Thought, 56, 58; idem, “Metaphysics and separatio,” 89-90,
102. I will consider this objection toward the end of this article.
37
Wippel, Metaphysical Thought, 47; idem, “Metaphysics and separatio,” 78. In
Boet. De Trin. q. 5, a. 3 (Leonine ed., 50:149, ll. 275-79): “Thus, therefore, a three-fold
distinction is found in the operation of the intellect. One according to the operation of
the intellect of composing and dividing, which is properly called “separation,” and this
befits the divine science or metaphysics.” See above for my discussion of the need for
varying degrees of removal from matter in the definitions of the subject-genera of
essentially distinct sciences.
38
Wippel, Metaphysical Thought, 47; idem, “Metaphysics and separatio,” 78-79.
39
In Boet. De Trin., q. 5, a. 3 (Leonine ed., 50:149, ll. 270-74): “Substantia autem,
que est materia intelligibilis quantitatis, potest esse sine quantitate; unde considerare
substantiam sine quantitate magis pertinet ad genus separationis quam abstractionis.”
40
See STh I, q. 76, a. 4 (Leonine ed., 5:223-24); Q. D. De Anima, a. 9 (Leonine ed.,
24/1:81, ll. 212-17); I Sent., d. 8, q. 5, a. 2 (Mandonnet, ed., 1:228-29).

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we distinguish one [object of thought] from another by
understanding that the one does not inhere in the other.”41
Wippel also points to the fact that to seek that by which a
thing is a being is not the same as to seek that by which a thing
is this or that kind of being, so that the answers to these
inquiries are not necessarily the same:
Without presupposing that there is any thing which is not living and material
and mobile, we can still ask why any thing which we experience enjoys being.
To ask this is very different from asking what kind of being it enjoys. If these
two questions are not identical, if follows that the answer to the one does not
have to be identified with the answer to the other. That by reason of which
something is recognized as enjoying being need not be identified with that by
reason of which it enjoys this or that kind of being. Therefore, we may
investigate one and the same physical and changing thing from different
perspectives. We may study it insofar as it is material and mobile, or insofar as
it is living, or insofar as it is quantified. But we may also study it insofar as it
enjoys reality at all, i.e., insofar as it is a being.42

Applying this to the claim about substance, we can consider
substance, the primary sort of being, merely as being. The
earlier text seems to warrant our saying that the notion of
substance does not include quantification, so that it can be
considered apart from that and all its attendants, such as
sensible matter and motion.
Wippel argues, then, that this negative judgment which is at
the root of metaphysics is not the statement that some being is
not material, but the statement that substance, and therefore
being, need not be material. He thus concludes that one can
achieve the understanding of being as being, the subject of

41

In Boet. De Trin., q. 5, a. 3 (Leonine ed., 50:148, ll. 161-62): “secundum
operationem qua componit et diuidit, distinguit unum ab alio per hoc quod intelligit
unum alii non inesse.”
42
Wippel, Metaphysical Thought, 61; see also idem, “Metaphysics and separatio,”
103.

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metaphysics, without a prior proof of the real existence of an
immaterial being, but by the process of separation.43
There can be no argument to the effect that the notion of ens
commune or of substance requires material. All parties agree on
this. The question is the means by which we grasp that fact: Do
we need an argument from natural philosophy, or can the
intuition of being get us there, or does the separation of
substance from quantity do the trick, or is there some other
way? If the subject of metaphysics is ens commune, or substance
taken without any necessary reference to material, that subject
must be known to be coherent before the science is undertaken.
We may be tempted to say, “I see no reason that there cannot
be immaterial being,” but this would be beside the point in the
pursuit of knowledge. It is as if one should say, “I do not see
that water includes hydrogen in its definition, so I will have a
science of hydrogen-free water.” It is not enough not to see a
problem; one must see that there is no problem. We have not
seen every possible argument; we only have seen the ones we
have already come up with. The future of philosophy may be,
for all we know, relentlessly materialist. If we do not have
positive assurance that being as being need not involve matter
we may only be spinning out the consequences of a selfcontradictory concept, a concept that will not be discovered to
be such, perhaps, until some distant future, if ever. Simple
failure to detect the presence of matter in the notion of being or
substance is therefore inconclusive.44
How, then, can we find the assurance we need of the legitimacy of the notion of an ens commune that does not necessarily
include material? The text of St. Thomas concerning the separability of substance from quantity simply does not address the
question of how we know that substance is separable from
43

See Wippel, Metaphysical Thought, 60-62; idem, “Metaphysics and separatio,”
102-4. A similar text is found in John F. Wippel, Metaphysical Themes in Thomas
Aquinas II, Studies in Philosophy and the History of Philosophy 47 (Washington, D.C.:
The Catholic University of America Press, 2007), 40-41.
44
See Wippel, “Metaphysics and separatio,” 104: “At least separatio will have
indicated that, insofar as one can determine, there is nothing within the intelligible
content of being as such to imply that it must be material” (emphasis added).

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411

matter; it only says that it is.45 Saint Thomas’s statement may be
reflective of an argument that he does not present here. Just as
St. Thomas assumes but does not prove (in this text) that there
is a God, so he may assume and not prove that substance is
separable from matter. This should not be surprising, as the
burden of questions 5 and 6 of the expositio on Boethius’s De
Trinitate is not to pursue the sciences but to reflect on their
differences and methodologies.
How, then, do we understand this separability? As we have
seen, the fact that I do not see a contradiction when I try to
think of substance as immaterial does not permit me to say that
the notion is coherent. Nor will induction help: on that basis,
one would certainly expect all beings to be material, just as we
often think that all bodies must have mass simply because all the
bodies we experience have mass. Is it possible that there be a
body without mass? Or is there a latent contradiction here? This
is a matter for argument. Similarly, we need some reason to
grant the separability of substance and matter even on the level
of the negatively immaterial.
Given the context of St. Thomas’s remark about substance—
that is, a discussion of the order in which accidents come to a
substance—one might think that, just as we can recognize
without argument that mathematical objects do not have
sensible matter in their definitions, so we can see that substance
does not have quantity or matter in its definition. We might
here invoke the priority of substance to quantity as we invoke
the priority of quantity to sensible quantity in order to ground
mathematics. But if we are going to claim that it is by separatio
and not by abstractio that we know this about substance, we
would have to add that substance is able to exist without
quantity and matter. This would presuppose a deeper
knowledge about substance, for it is not obvious that any real
substance is or can be without quantity, just as it is not obvious
that any quantity can exist without being really joined to
45

In Boet. De Trin., q. 5, a. 3 (Leonine ed., 50:149, ll. 270-74).

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sensible matter (in fact this latter is impossible). Earlier in the
paragraph in which St. Thomas says that the consideration of
substance belongs more to separation than to abstraction, he
says,
Similarly, when we say that form is abstracted from matter, this is not
understood about substantial form, because substantial form and the material
corresponding to it depend on each other, so that one cannot be understood
without the other, for this reason, that the proper act is in its proper
material.46

Of course, this text does not contradict the claim that there are
immaterial substances, but it certainly should give one pause.
How can there be a form that is not the act of a material? Isn’t
form always the form of something, of some subject? Or could
there be a being which neither is nor has form? We need some
reason to think that this is not a self-contradiction. Without
such a reason, we do not know that form (and so substance) is
at all separable from matter.
Instead of focusing on the statement about substance and its
supposed indifference to matter, one might insist that the
difference between the questions “Why is it this sort of being?”
and “Why it is it a being at all?” indicates different
intelligibilities such that a thing can be considered as a being
without being considered as this sort of being, in particular,
without being considered as material.
Though the argument has an air of plausibility, it fails
because, while it is not necessary that the answers to two
different questions be the same, neither does anything prevent
two different questions from having the same answer. “What is
2 + 2?” “What is 10 – 6?” We cannot deduce from the fact that
these questions are different that their answers are different.
Just so, in the absence of further evidence, we cannot say that
the answer to the question “What makes a being this sort of

46
In Boet. De Trin., q. 5, a. 3 (Leonine ed., 50:149, ll. 258-63): “Similiter autem
cum dicimus formam abstrai a materia non intelligitur de forma substantiali, quia forma
substantialis et materia sibi correspondens dependent ad inuicem, ut unum sine alio non
possit intelligi, eo quod proprius actus in propria materia fit.”

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413

being?” is not always the same, at least in part, with the answer
to the question “What makes a being a being at all?” We cannot
presume that the answer in each case is not inextricably bound
to the answer, “matter,” whether that answer be partial or
complete. What makes a dog a dog and what makes a rock a
rock are distinct, but in each case what makes them these sorts
of being as well as what makes them beings at all certainly does
involve matter.
The fact that we have different questions indicates that we
may have different answers, not that we do have different
answers, and the fact that we do have different answers does not
require that the answers be different in every way—here, in
particular, that one or more of the answers does not involve
matter. And if all beings are like this, then no beings could be
immaterial and there would be no removal from matter by way
of separatio and so no science of metaphysics.47 It would be as
false to say that there are predicates that name something able
to be without matter as to say that there are predicates that
name things that in fact have no matter. To take a parallel case,
“regular solid” does not include in its very ratio that the set of
such solids be limited to five, but this fact does not indicate that
there can be more than five, even if we have not yet found the
argument proving that there are only five.48 Had that proof
never been found, the truth of the matter would remain
unchanged. So too, “being” does not contain in its ratio that it
is limited to material, but this does not mean that it is not. The
witness of St. Augustine, who admits that at one point in his life
he could not even conceive of being which was not material,
again comes to mind.49
Wippel also addresses the objection that his view has left us a
metaphysics built on sand, on mere possibility.50 He claims that
47

See Aristotle, Metaphysics 6.1.1026a 27-32; VI Metaphys., lect. 1 (Marietti ed.,
1170).
48
That there are, in fact, only five, is proven by Euclid (Elements, 13.18).
49
Confessions 5.10.19.
50
Wippel, Metaphysical Thought, 61.

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he is not grounding metaphysics on bare possibility because the
existence of the real objects with which he begins is no mere
potential, but is given as actual in our experience of sensible
beings. This last point is certainly true, but the argument itself is
unpersuasive. But the real existence of sensible being offers no
assurance (without an argument from natural philosophy) that
an existence without material is even a coherent idea. And if it
is not really possible to separate matter and being, we cannot
justify the separatio needed to begin metaphysics.
D) By the Third Act of the Intellect within Metaphysics
Could we, then, entirely leave aside the demand for knowledge of even negatively immaterial being before we launch into
metaphysics? Joseph Owens suggests that we can, immediately
entering metaphysics simply by considering being as being,
assuming only the reality of things within the material cosmos
and their existences, and all this even without Wippel’s
insistence that we see from the start some possibility for
negatively immaterial being. Owens grants that we need the
third act of the mind to get to the immaterial, but denies that
we need the immaterial before we start metaphysics; we can
start metaphysics with sensible, mobile being.51
In fact, we may grant, if the science of metaphysics is as St.
Thomas describes it, that there must be a universal notion of
being which, though applicable to material beings, nevertheless
prescinds from or excludes matter.52 For example, we might
define being or the existent as “what exists,” or as “quod habet
esse,”53 expressions that have no overt reference to matter.
Metaphysics begins with the sensible being around us, which,
insofar as it is being, has a unique intelligibility, one different
51

See Knasas, Being and Some Twentieth-Century Thomists, 65-70; Owens,
“Metaphysical Separation,” 303.
52
In Boet. De Trin., q. 5, a. 4, ad 6 (Leonine ed., 50:156, ll. 314-19); II Sent., d. 3,
q. 3, a. 2 (Mandonnet, ed., 2:116); IV Metaphys., lect. 1 (Marietti ed., 529-32);
III Metaphys., lect. 4 (Marietti ed., 384).
53
E.g., STh I-II, q. 26, a. 4 (Leonine ed., 6:190-91); XI Metaphys., lect. 3 (Marietti
ed., 2197).

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from that of mobile being as such.54 The latter, for example, is
analyzed into form and matter, the former into essence and
existence.55
The being that places a thing under the subject of metaphysics is the being that
is immediately known in sensible things through each ordinary, everyday
judgment, and that is everywhere universalized by the ordinary man in a
subsequent concept. . . . It is what is first grasped through judgment in the
concretion of the sensible thing, as the thing is immediately known in sensible
experience. It is not something esoteric or far-fetched, but is familiar to
everyone in every cognitive act.56

This original grasp of being, which is had through
judgment,57 does not actually include the possibility of the
immaterial. From the consideration of being as being, taken in
its sensible manifestation, we can argue to the existence of a
subsistent, infinite, immaterial being, using some form of the
argument in De ente et essentia.58 Owens is not saying that we
have an “intuition of being” in Maritain’s sense, for he clearly

54
According to St. Thomas, being as being is the subject of metaphysics, while
mobile being is the subject of natural philosophy. Though mobile being and quantified
being are parts of being, natural philosophy and mathematics are not parts of
metaphysics. Owens states his position briefly in “Metaphysical Separation,” esp. 302-4.
For a summary of Owens’s position, see Knasas, Being and Some Twentieth-Century
Thomists, 65-69; idem, Preface to Thomistic Metaphysics, 71-74. See also In Boet. De
Trin., q. 5, a. 1, ad 6 (Leonine ed., 50:141, ll. 322-33); Metaphys., pro.; III Metaphys.,
lect. 4 (Marietti ed., 384); IV Metaphys., lect. 1 (Marietti ed., 530); VI Metaphys., lect.
1 (Marietti ed., 1165); XII Metaphys., lect. 1 (Marietti ed., 2421); ScG II, c. 37
(Leonine ed., 13:353-54).
55
Owens, Elementary Christian Metaphysics, 303.
56
Ibid., 370-71; see also Owens, “Metaphysical Separation,” 302-3.
57
Owens, Elementary Christian Metaphysics, 48-49: “The activity by which the
human mind grasps anything, then, is always complex. Through simple apprehension, it
knows the thing according to the thing’s nature, and at the same time through judgment
it knows the thing according to the thing’s being.” See also ibid., 195-96.
58
De ente et essentia, c. 4 (Leonine ed., 43:377, ll. 127-46). See Owens, Elementary
Christian Metaphysics, 80-83; idem, “Metaphysical Separation,” 306. Knasas states that
Owens is the only Thomist to develop metaphysics based exclusively on the notion of
sensible being (Being and Some Twentieth-Century Thomists, 65-66).

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states that we must argue, based on the notion of being obtained
in our original encounter with reality, to the existence of the
immaterial; nor is he agreeing with Wippel that we must have a
“negatively immaterial” notion of being before we start
metaphysics.
As originally grasped by the human intellect, being, though a transcendent
aspect, does not at once manifest itself as transcendent. When its primary
sense is reached in subsistent being, its literal meaning is seen to extend
beyond the sensible and beyond the finite orders. 59

We might defend Owens’s view by looking at the difference
between mathematics and natural philosophy. In mathematics,
we merely consider in a new way what was considered in
another way in natural philosophy. The sphericity of the moon,
for example, is treated in one science as the limit of a sensible
body, whereas in the other it is treated apart from sensible
matter.60 Why not similarly say that we can treat physical things
either as beings or as mobile?
In the case of mobile being and mathematicals, the subjectgenera exist in the same external objects: everything mobile is
quantified and everything quantified is mobile.61 We would not
be extending our reach to beings beyond our original ken,
either at the beginning or at a later stage of our new science.
Would we have a new science? Yes, if we defined our subjectgenus without sensible matter; no, if we did not.62 The

59
See Owens, Elementary Christian Metaphysics, 97 n. 21. One might argue that
Owens’s view of ens commune is the same as Wippel’s. I would not agree, and I will
treat them differently for the purposes of this essay.
60
See II Phys., lect. 3 (Leonine ed., 3:62 [Marietti ed., 159-61]); VI Metaphys., lect.
1 (Marietti ed., 1156-61); In Boet. De Trin., q. 5, a. 3, ad 1 (Leonine ed., 50:149-50, ll.
291-302).
61
VI Phys., lect. 5 (Leonine ed., 3:284-87 [Marietti ed., 796-805]); XI Metaphys.,
lect. 1 (Marietti ed., 2162). See also Coughlin, ed., Physics, 141-42 n. 19; and Glen
Coughlin, “The Ground and Properties of Time,” The Aquinas Review 19 (2013-14):
23-78,
esp.
25-35
(https://thomasaquinas.edu/pdfs/aquinas-review/201314.pdf#page=31).
62
In Boet. De Trin. q. 5, a. 3, ad 4 (Leonine ed., 50:150, ll. 335-42). Einstein, for
example, seems to think of mathematics as true (as opposed to consistent) only if it is

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extension of the genus in terms of number of referents or even
number of kinds of referents is not what is crucial here; what is
crucial, what causes there to be a new science, is, as we saw
above, the mode of definition and, particularly, the way that
mode incorporates or does not incorporate matter.
In mathematics, then, we know we have a new mode of
definition because we know that we can define quantitative
objects like circles, triangles, and numbers fully and completely
without reference to sensible matter. We see that “three-sided
plane figure” has no reference to sensible matter and yet no
defect as a definition of a triangle—any such reference would be
accidental to the notion of a triangle. Our certitude about this is
finally based on the point of resolution of mathematics, the
imagination.63 Because we can recognize that the principles of
mathematics are present in the homogenous space of our
imaginations, and that we do not need heat or weight or any
other sensible quality to define the objects of mathematics, we
are assured that mathematics as a science separate from natural
philosophy is possible.64
What would be the corresponding assurance that we can
treat being as being in some way other than that which is used
by the natural philosopher? We cannot start metaphysics with a
concept of being still wrapped up in matter. We would still be
in natural philosophy, for definition with matter is the hallmark
of that science.
On the other hand, a definition that does not refer to matter
could not be a principle of our science at this stage either, for it
would have to be either common to the material and the
immaterial, or else proper to the immaterial. The latter poses an
obviously fundamental problem: if we do not know that there
resolved to sensible matter. See Albert Einstein, Relativity: The Special and General
Theory (New York: Wing Books, 1961), 3-5.
63
In Boet. De Trin., q. 6, a. 2 (Leonine ed., 50:164-65, ll. 95-116).
64
Saint Thomas goes so far as to say that mathematical objects have only a remote
foundation in extramental reality and compares them in this regard with logical
intentions: I Sent., d. 2, q. 1, a. 3 (Mandonnet, ed., 1:67).

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are immaterial things already, we do not even know that any
supposed “definitions” or “rationes” of them are not selfcontradictory. In any case, for St. Thomas the subject of
metaphysics is not the positively immaterial separate
substances.65
If the definition of the subject of our science does not
include or exclude matter, it must, in a manner reminiscent of
the “absolute nature,”66 be indifferent to matter, that is, it must
be in some sense common to the material and to the immaterial.
But if one supposes here at the beginning of metaphysics (as
Owens must allow, given his claim that we only prove the
existence of immaterial being in metaphysics itself) that there
may in fact be no immaterial being—or even more, that
immaterial being may contain a latent contradiction—then the
definition without matter, to be employed at the beginning of
metaphysics, would be true of, at most, the material. Thus, the
definition would be only a dialectical and imperfect definition
of the material, like the definition of “anger” in De anima as “a
desire for revenge.”67 Such definitions, though they are of things
which are essentially material, do not mention matter, but the
complete definition of anger would have to include some
reference to the material in which such a physical passion exists.
This sort of dialectical definition is not sufficient for the subjectgenus of a science.68
To see this insufficiency more clearly, we need to add to our
previous discussion of the presuppositions of science. Every
science is about something and says something about it.69 What
it speaks about is the subject-genus (e.g., mobile being or
quantitative being) or some things contained under the subjectgenus (e.g., plants or numbers). The science aims to
65

In Boet. De Trin., q. 5, a. 4 (Leonine ed., 50:154, ll. 75-206).
The absolute nature is the nature considered as it exists neither in re nor in mente;
it is the nature all by itself, considered without any esse or accidentally connected forms.
See De Ente, c. 3 (Leonine ed., 43:374, ll. 26-51).
67
Aristotle, De anima 1.1.403a29-b1.
68
I De Anima, lect. 2 (Leonine ed., 45:11-12 [Marietti ed., 24-29]). See also STh I,
q. 20, a. 1, ad 2 (Leonine ed., 4:253).
69
I Post. Anal., lect. 2 (Leonine ed., 1/2:10, ll. 17-27 [Marietti ed., 14]).
66

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419

demonstrate certain attributes or even certain causes or effects
of that subject-genus, or of some part of it.70 The predicate of
our conclusion will be something we see to exist or to be true of
the subject-genus (or its part) by way of an argument, the
middle term of which is, ultimately, the definition of the
subject-genus.71 We see prime matter in natural philosophy as
implied by mobile being (or especially its part, substantially
changeable mobile being); we see that the predicates of our
conclusions belong to their subjects through the definitions of
those subjects.72
So we see why we must begin with a more than dialectical
knowledge of the existence and the definition of the subjectgenus: these are first principles of the science, than which there
is nothing more basic within the science. We cannot prove the
existence of the subject-genus within the science of that subjectgenus. And yet we must know it exists in some way: if we do
not know that the thing we are talking about exists, either by
direct experience or by an argument from what is given in
direct experience, we are not only ignorant of its actual
existence, but even of its possible existence. As we saw earlier,
the fact that we see no contradiction in its notion guarantees
nothing. Thus, Aristotle argues that to have science we must
know that the subject exists and what it is,73 and, moreover, that
knowing that it is comes before knowing what it is.74 Saint

70

I Post. Anal., lect. 15 (Leonine ed., 1/2:57, ll. 34-42 [Marietti ed., 129]).
Ibid.; cf. also I Post. Anal., l. 23, nn. 192-97 (Leonine ed., 1/2:84-85, ll. 1-97).
72
Again, there can be many middle terms, but the ultimate one, the one to which the
argument must reduce, is the definition of the subject-genus. See I Post. Anal., lect. 2
(Leonine ed., 1/2:11-12, ll. 50-112 [Marietti ed., 16-17]); lect. 41 (Leonine ed.,
1/2:153-54, ll. 129-92 [Marietti ed., 362-63]).
73
Aristotle, Posterior Analytics 1.10.76a32-36; see also I Post. Anal., lect. 18
(Leonine ed., 1/2:67, ll. 37-58 [Marietti ed., 152]).
74
Aristotle, Posterior Analytics 2.1.89b31-35; see also II Post. Anal., lect. 1 (Leonine
ed., 1/2:175, ll. 97-110 [Marietti ed., 411]).
71

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Thomas says, “It is vain to seek what a thing is if one does not
know that it is.”75 A little before, he gave the reason:
For because there is no quiddity or essence of a non-being, no one is able to
know the “what it is” about what does not exist; but one is able to know the
signification of the name, or the notion composed from many names: just as
one is able to know what this name “goat-stag” . . . signifies, because it
signifies a certain animal composed from a goat and a stag: but it is impossible
to know the “what it is” of a goat-stag, because there is no such thing in rerum
natura.76

On the understanding of Owens, we do know that beings exist,
because we know that material beings exist. We may also have a
less perfect, merely dialectical definition of these just insofar as
they are beings, a definition that does not include matter. This
definition, whatever it is, is presented as the most fundamental
one within the science, and it is denied that any definition of
the subject can rely on any prior science, such as natural
philosophy. This definition must therefore be sufficient for the
science. This could be true only if, first, the definition expresses
75

II Post. Anal., lect. 7 (Leonine ed., 1/2:199, ll. 162-63 [Marietti ed., 476]):
“Vanum autem est querere quid est, si aliquis nescit quia est.”
76
II Post. Anal., lect. 6 (Leonine ed., 1/2:194, ll. 17-26 [Marietti ed., 461]): “Quia
enim non entis non est aliqua quiditas uel essencia, de eo quod non est nullus potest
scire ‘quod quid est,’ set potest scire significationem nominis, uel rationem ex pluribus
nominibus compositam, sicut potest aliquis scire quid significat hoc nomen ‘tragelaphus’
vel ‘yrcocervus’ (quod idem est), quia significat quoddam animal compositum ex yrco et
ceruo; set impossibile est scire ‘quod quid est’ yrcocervi, quia nichil est tale in rerum
natura.” Saint Thomas’s reference to a thing existing “in rerum natura” might seem to
indicate that the object of science must be real outside the mind. Yet this would do away
with the sciences of mathematics and logic. Rather, he means the nature must exist in
the sense of being possible, as we might say “there is such a thing as a dodecahedron.”
This is opposed to a mere figment of the imagination, such as a goat-stag. It is worth
noting that St. Thomas says we cannot know what a goat-stag is not because it does not
actually exist, but because there is no such thing, that is, there is no such sort of thing
(“nihil est tale in rerum natura”). We might say, to take another example, “there is no
such thing as a greatest prime number,” meaning not that we do not find one existing
right now, but that the very kind of thing has no purchase on reality, precisely because it
is a self-contradiction. See also STh I, q. 2, a. 2, ad 2 (Leonine ed., 4:30): “the question,
‘what is it?,’ follows upon the question, ‘whether it is?’” (“questio quid est, sequitur ad
questionem an est”); Aristotle, Posterior Analytics 1.8.93a26-27: “to seek what it is, not
knowing that it is, is to seek nothing.”

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whatever is essential to its subject and, second, it may thus give
rise to per se properties. But clearly a dialectical definition is not
sufficient for either task.
Matter is, after all, not incidental to material beings but
included in their very definitions.77 With regard to the
dialectical definition of anger proposed in De anima, St.
Thomas says, “But that the first definition (the dialectical
definition of anger) is insufficient appears manifestly. For every
form which is in determinate matter, unless there be put in its
definition material, that definition is insufficient.”78 To be
material is not a mere accident in material things. Moreover,
from such a dialectical definition, mistakenly understood as
complete, one would draw false conclusions. For example, if
there is no material component in the definition of anger, one
would think that anger is an accident of a separated substance.
Nor would it be a passion, but an act of the will alone,79 and,
moreover, a very stable or even permanent one.80 Horace’s
dictum, “anger is brief madness,”81 would be denied. Moreover,
it is generally true that the definition of the subject-genus must
be sufficient for the science because there is nothing prior to it
within the science, and so nothing from or through which one
might elaborate a sufficient definition. If there were, that other
thing would be the real subject-genus, for the predications of
the science would finally be about that thing.82

77
De Ente, c. 2 (Leonine ed., 43:370, ll. 1-37); see also II Post. Anal., lect. 7
(Leonine ed., 1/2:198, ll. 35-38 [Marietti ed., 471]).
78
I De Anima, lect. 2 (Leonine ed., 45:11 [Marietti ed., 25]): “Quod autem diffinitio
prima (i.e., dialectica) sit insufficiens, manifeste apparet. Nam omnis forma que est in
materia determinate, nisi in sua diffinitione ponatur materia, illa diffinitio est
insufficiens.”
79
STh I, q. 59, a. 1 (Leonine ed., 5:92).
80
II Sent., d. 7, q. 1, a. 2 (Mandonnet, ed., 2:184-85); STh I, q. 64, a. 2 (Leonine
ed., 5:141-42); De Verit., q. 24, a. 10 (Leonine ed., 22/3:707, ll. 303-13); De Malo, q.
16, a. 5 (Leonine ed., 23:304-6).
81
Horace, Epistles 1.1.62.
82
I Post. Anal., lect. 17 (Leonine ed., 1/2:57, ll. 40-42 [Marietti ed., 5]).

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But do we not know that the definition does have reference
to a real thing because, even if it is an imperfect definition of
anger, it is still of something we know to be real, namely,
anger? We might then try to carry this thought over to the case
at hand and say that our dialectical definition of being or one,
or other such things, has real reference to the material beings
around us, and so we know that our definition does not express
something impossible.83 But it does not follow that it is possible
as stated; in other words, the addition of the proper material
principle might be necessary for the very possibility of what is
correctly laid out in the dialectical definition. For example,
anger as dialectically defined certainly exists, but perhaps its
existence has a real dependence on what is not stated in the
definition, the material element of anger—and as we know, it
certainly is so dependent. Moreover, our inability to see an
absurdity within or following from the definition as given does
not imply that there is none.
It is clear, then, that a dialectical definition is not up to snuff
as a principle of metaphysics or of any other science. Owens’s
view, then, cannot stand.
The attempt to begin metaphysics with a matter-free definition of material being cannot succeed. We may reflect too that,
if we do have a proof of the immaterial from natural
philosophy, we avoid all these problems and immediately
recognize that we need a new and more universal science.
Lacking that proof, we lose that immediate motivation for a
new science; our inquiry is reduced to a quixotic essay in search
of a subject.84 It is unnatural, it seems to me, to seek knowledge
of immaterial beings when we do not even know they are
83
This akin to Wippel’s statement, discussed above, that metaphysics, as he
understands it, is based not on possibility but on the actuality of sensible being
(Metaphysical Thought, 61).
84
Wippel, for example, criticizes Knasas on the grounds that the latter would begin
metaphysics with sensible things (in this, Knasas is following, as it seems to me and to
him, Owens) and prove the existence of the immaterial within metaphysics, thus
abrogating the demand that a science does not prove the existence of its own subject
(Metaphysical Thought, 58-59 n. 110). Knasas responds in Being and Some TwentiethCentury Thomists, 68-69 n. 77.

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possible, or even to seek knowledge of material being defined,
for some unknown reason, without matter.
These considerations help us see what is wrong with the
purported likeness to mathematical science. Mathematical objects are completely and fully defined in abstraction from
sensible matter: any sensible matter they might exist in outside
the mind is accidental to what the mathematical objects are.85
The sphere, as such (i.e., as the mathematician considers it), is
neither bronze nor gold, except accidentally. But it is not the
case that the adjective “material” in “material being” expresses
something merely accidental; it is more like “rational” in
“rational animal,” an adjective that qualifies the noun per se.
We cannot simply remove the “material” in “material being”
and be assured that we have an intelligible subject, as we can
when we remove the “bronze” in “bronze triangle.” While the
abstract definitions of mathematics are real definitions and we
know it, the definition of being without matter might turn out
in our hands to be nothing but a mare’s nest.
E) By the Third Act of the Intellect within Natural Philosophy
Having seen that we cannot base metaphysics directly on experience of something immaterial or on abstraction of an immaterial notion from a material being, or on an “intuition of
being,” or on a separation in judgment, or on an argument
precipitously metaphysical, we are left with one option only: to
have a science of metaphysics, we must arrive at the notion of a
thing to be defined without matter by way of an argument
starting from what is already known in natural science, namely,

85

VI Metaphys., lect. 1 (Marietti ed., 1161): “Mathematics differs from physics in
this, therefore, that physics considers those things the definitions of which are with
sensible matter. And therefore it considers things not separated insofar as they are not
separated. Mathematics, indeed, considers those things the definitions of which are
without sensible matter. And therefore, even if the things it considers are not separated,
still, it considers them insofar as they are separated.”

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mobile being. This is implied by many texts of St. Thomas. For
example,
To the second it must be said that certain things are knowable by us through
themselves, and for manifesting such things speculative sciences use their
definitions for demonstrating their properties, as happens in the sciences
which demonstrate propter quid. There are, indeed, things which are not
knowable by us from themselves, but through their effects. And if, in fact, the
effect measure up to the cause, the very quiddity of the effect is taken as a
principle for demonstrating that the cause exists and for investigating its [i.e.,
the cause’s] quiddity, from which, further, its properties are shown. If,
however, it be an effect which does not measure up to the cause, then the
definition of the effect is taken as a principle for demonstrating that the cause
exists, and some conditions of it, however much the quiddity of the cause be
forever unknown; and so it happens in [the case of] separated substances.86

Note that St. Thomas affirms that we can show that the
separated substances exist by way of a demonstration, and that
in that demonstration the definition of the effect will play the
role of a middle term. Moreover, it is clear from the corpus of
this article that he is referring to sensible effects:
The quiddities of separated substances are not able to be known through those
things which we take from the senses, as is clear from what has been said,
however much we may be able, through sensible things, to come to knowing
that the aforesaid substances exist and some of their conditions. And so
through no speculative science is “what it is” able to be known about some
separated substance, however much we be able to know through speculative
sciences that these exist and some of their conditions, e.g., that they are
intellectual, incorruptible, and things of this sort.87
86
In Boet. De Trin. q. 6, a. 4, ad 2 (Leonine ed., 50:171, ll. 159-75): “Ad secundum
dicendum, quod quedam res sunt a nobis per se ipsas cognoscibiles, et in talibus
manifestandis scientie speculatiue utuntur earum diffinitionibus ad demonstrandum
ipsarum proprietates, sicut accidit in scientiis que demonstrant propter quid. Quedam
uero res sunt que non sunt nobis cognoscibiles ex se ipsis set per effectus suos; et si
quidem effectus sit adaequans causam, ipsa quiditas effectus accipitur ut principium ad
demonstrandum causam esse et ad inuestigandum quiditatem eius, ex qua iterum
proprietates eius ostenduntur; si autem sit effectus non adaequans causam, tunc
diffinitio effectus accipitur ut principium ad demonstrandum causam esse, et aliquas
conditiones eius, quamuis quiditas cause sit semper ignota. Et ita accidit in substantiis
separatis.”
87
In Boet. De Trin., q. 6, a. 4 (Leonine ed., 50:170, ll. 136-46): “Quiditas autem
substantiarum separatarum non potest cognosci per ea quae a sensibus accipimus, ut ex

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As we have already seen, St. Thomas understands the quiddities
of sensible things to include sensible matter, so the science he is
speaking of here must be one that considers things that have
sensible matter in their definitions—and, unless he is speaking
loosely and even per accidens, sensible matter must be included
in their definitions insofar as they are principles of the
arguments in question. He is not speaking about probable or
dialectical arguments. But, as we know, there are only three
fundamental speculative sciences, and only one of these deals,
per se, with the quiddities of sensible substances, namely,
natural philosophy.
John Knasas, echoing Owens,88 points out that St. Thomas
explicitly says only that progress to the immaterial is from the
sensible, but does not say that this occurs within natural
philosophy. While true, the point is of little probative value.
This interpretation is a tortured one, intended to defend a
thesis, not the natural reading an unbiased reader would give
the text. Owens cites the following text: “sensible effects, from
which natural demonstrations proceed, are more known to us in
the beginning, but when we shall have come to knowledge of
the first causes through them. . . .”89 The context is a discussion
of an objection that, if natural science lends principles to
metaphysics and metaphysics turns around and proves the
principles of natural science, we are involved in a vicious
circle.90 Are we really to believe that, in such a context, the
praedictis patet; quamuis per sensibilia possimus deuenire ad cognoscendum praedictas
substantias esse, et aliquas earum conditiones; et ideo per nullam scientiam speculatiuam
potest sciri de aliqua substantia separata quid est, quamuis per scientias speculatiuas
possimus scire ipsas esse, et aliquas earum conditiones, utpote quod sunt intellectuales,
incorruptibiles, et huiusmodi.”
88
Joseph Owens, “Aquinas and the Proof from the Physics,” Mediaeval Studies 28
(1966), 119-50, at 131; Knasas, Preface to Thomistic Metaphysics, 35.
89
In Boet. De Trin., q. 5, a. 1, ad 9 (Leonine ed., 50:141, ll. 371-75): “effectus
sensibiles, ex quibus procedunt demonstrationes naturales, sunt notiores quoad nos in
principio, set cum per eos peruenerimus ad cognitionem causarum primarum. . . .”
90
In Boet. De Trin., q. 5, a. 1, ad 9 (Leonine ed., 50:141, ll. 361-71).

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expression “natural demonstrations” is not to be understood as
referring to demonstrations in natural science? And that these
demonstrations in natural science do not lead to knowledge of
first causes, that is, immaterial causes? Even if St. Thomas does
not explicitly attribute the arguments in question to natural
science, we should recognize that neither does he explicitly
deny this nor explicitly attribute these arguments to
metaphysics. Given all we have seen in this article, it is much
more reasonable to take the text as one of St. Thomas’s
characteristically formal statements, that it is from the sensible
as such, and therefore from within natural philosophy, that one
reaches out to the immaterial.91
III. THE NEED FOR NATURAL PHILOSOPHY
This is only to be expected. All our knowledge begins in
sensation and so with the natures and attributes of material
things; we must approach immaterial things through material
things. But material things are of a wholly other nature than the
immaterial; consequently, we cannot approach the latter by
simply looking at what is intrinsic to material things. We must
get from the material to the immaterial by a necessary link, but
one which appeals from what is actually present in material
things to what is not actually present. The link must, therefore,
91

See also, for example, Q. D. De Anima., a. 16 (Leonine ed., 24/1:145-46, ll. 31032): “And therefore one must say otherwise, that the intellectual human soul, due to
union with the body, has an act of seeing inclined to phantasms; whence it is not
informed so as to understand something except through species taken from phantasms. .
. . To this degree, then, is the soul, while it is united to the body, able to ascend to the
knowledge of the separated substances, so far as it is able to be led by the hand through
species taken from phantasms. But this does not happen in such a way that it be
understood about them what they are, since those substances exceed every proportion
of these intelligibles; but we are able in this way to know ‘that they are’ in some way
about the separated substances; just as through deficient effects we come to causes
which exceed, so that we can know about them only that they are; and while we know
that they are causes which exceed, we know about them that they are not such as are
their effects. And this is to know about them more what they are not than what they
are.” The species taken from the phantasms are, of course, the quiddities of natural
bodies and their accidents. See also I Sent., d. 3, q. 1, a. 2, ad 2 (Mandonnet, ed., 1:94).

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be founded on some form of extrinsic causality, either final or
agent or exemplar,92 and so can only be established by
argument, the third act of reason, for judgment and abstraction
alone cannot bring out anything but what is intrinsic to the
subject. For this reason, St. Thomas says, “our intellect is not
proportioned to knowing something by natural knowledge
except through sensibles; and therefore it is not able to arrive at
pure intelligibles except by arguing.”93
A) An Example from the “Physics”
The arguments in question will have to conclude to the
existence of nonmaterial realities. Such an argument is given by
Aristotle in the Physics. He argues that there must be a first
mover and that this first mover must have infinite power. Since
no body can have infinite power, we draw the negative
92

De principiis naturae, c. 3 (Leonine ed., 43:41, ll. 47-51): “He takes ‘causes’ as
much for what is extrinsic as for what is intrinsic. Matter and form are said to be
intrinsic to the thing in virtue of the fact that they are parts constituting the thing,
efficient and final are said to be extrinsic because they are outside the thing.” See also III
Sent., d. 10, q. 2, a. 1, qcla. 3 (Moos, ed., 3:344): “One can note, too, the formal cause,
and this in two ways, either inhering, or exemplar.” I do not here mean to suggest that
just any kind of extrinsic causality can be used, but that only an extrinsic kind can be
used. It seems to me that we must use agent causality, but that is not my direct concern
here.
93
I Sent., d. 3, q. 1, a. 2, ad 2 (Mandonnet, ed., 1:94): “sed intellectus noster non est
proportionatus ad cognoscendum naturali cognitione aliquid nisi per sensibilia; et ideo
in intelligibilia pura devenire non potest nisi argumentando.” See also the corpus of this
article, where St. Thomas contrasts the way we know per se nota propositions
immediately from sensation to the way we come to the immaterial: “those which are
known to us as self-evident, are made known immediately through sense; just as, the
whole and the part being seen, we immediately know that every whole is greater than its
part, without any inquiry. Whence the Philosopher says, ‘we know the principles when
we know the terms.’ But sensibles being seen, we do not come to God except by
advancing, according as those things are caused and everything caused is from some
agent cause and the first agent is not able to be a body, and so we do not arrive at God
except by arguing.” In the same text, he specifies that certain other philosophers did not
come to see that God exists because they did not acknowledge the agent cause.

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conclusion that the first mover is not material.94 This separation
or negative judgment, a result of argument, is the sort of thing
St. Thomas means when he says that what characterizes
metaphysics is separation. There is no particular reason to think
that, when St. Thomas says that what is appropriate to
metaphysics is separation rather than abstraction, he means to
restrict us to judgments made immediately from experience, or
to exclude separations which are the results of arguments—in
particular, arguments in natural philosophy. He certainly does
not say this.
B) Three Objections
A number of problems may be raised; here I will only
address a few of the more pressing ones.
One might claim that if we are to prove something about
immaterial beings, if only their existence, and if we are to do so
from natural philosophy, the premises of our syllogism must
already contain a claim that transcends material being. The conclusion cannot contain more than the premises, so there is no
way to argue from the material to the immaterial (or, for that
matter, from the created to the uncreated; the same argument
would apply):
It is illusory to attempt to base a knowledge of being as being on the
demonstrated existence of immaterial things. Either “is” is freed from its
sensible and changing context (prior to the proof of the existence of
immaterial being, and thus is meaningful when we conclude to the existence
of such beings), 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.95

The meaning of the words in the premises must be the same as
their meaning in the conclusion; if not, we fall to equivocation.
94
Physics 8.10.266a10-b6; 267b17-26. See also VIII Phys., lect. 21 (Leonine ed.,
3:444-450 [Marietti ed., 1141-56]); lect. 23 (Leonine ed., 3:458 [Marietti ed., 1172]).
95
George Klubertanz, Introduction to the Philosophy of Being (2d ed.; New York,
1963), 52 n. 28.

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Yet the truth of the matter, however odd, is that we do argue
from the material to the immaterial (and from the created to the
uncreated). Saint Thomas, as we saw, goes so far as to say that
we can know nothing about the immaterial except by argument
from the material.96 He, at least, must think it is possible so to
argue. Exactly how we pull it off is a little more difficult to say.
It seems that we first prove the existence of immaterial things,
and when we do so, we are not yet aware that “being” must be
equivocal.97 We prove, for example, that there is a first mover
or we recognize that we have an intellectual power. Only later
do we realize that such things must be unbodily.98 To do so, we
must use demonstrations that have negative conclusions. For
example, we might argue that the first mover must have infinite
power, but no body has infinite power, and conclude that the
first mover is not a body. The major premise is seen by noting
that every body has finite power, so that what has infinite
power cannot be a body (i.e., no body has infinite power). But
we see that in order to explain motion, there must be something
of infinite power. Once we see all this, we can see that the first
mover is immaterial.99 We have proven, starting from notions
that include matter, that there is a transcendent, nonmaterial
being. The negative premises are seen by way of the negations
96

I Sent., d. 3, q. 1, a. 2, ad 2 (Mandonnet, ed., 1:94).
I say “equivocal” rather than “analogous” (though both are true; see the texts cited
at the end of note 25) in order to emphasize that, because at least two definitions are
involved, one cannot say that “being” (or “one,” etc.) as said of the material is
applicable to immaterial “being” and thus one cannot get from one to the other simply
from what one grasps in the original usage. If the meaning of the word is different, then
we need to bridge the gap between the meanings. This is why one cannot see the
possibility of the immaterial by looking at the material and what it contains, whether
one is looking at the simple concept of material being or at the subject of a judgment,
affirmative or negative. So long as the meanings of being as said of the immaterial and
the material are not the same, we cannot see the former in the latter.
98
Thus, St. Thomas first shows that God exists, and only later shows that he is
immaterial, and is even identical with his essence and existence (STh I, q. 2, a. 3
[Leonine ed., 4:31-32]; q. 3, aa. 1-4 [Leonine ed., 4:35-43]).
99
Aristotle, Physics 8.10.266a11-b6; 267b17-26.
97

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of the predicates of affirmative claims. We see what turns out to
be immaterial at first only as a cause, then we later see that
many of the predicates said of material things are to be denied
of it. This most of all brings home the fact that nothing is said
univocally of the immaterial and the material. Every positive
predicate must be hedged round with negation: yes, God exists,
but he does not have an existence which actuates a material
essence; yes, God is one, but not by the unity of continuous
magnitude; and so on.100 We arrive at negative judgments or
separations. These separations permit us to distinguish the
subject whose existence we have just proven from the subjects
of natural philosophy—to see, in fact, that there must be some
more universal science because being turns out to be more
universal than we had thought, that being as such and mobile
being are not coterminous and that there must be a new mode
of definition for our newly expanded subject.
Another objector might claim that St. Thomas himself clearly
says that the subject of metaphysics is being as being and that he
sees the goal of science as the uncovering of the principles of
the subject of the science.101 Metaphysics must be looking for
the cause of being as such. If, then, one has to prove the
existence of immaterial beings before beginning metaphysics,
one will already have found the cause of the subject just to start
the science, the goal of which was purportedly to find that very
cause. For the causes of being as being are the immaterial,
immobile beings, especially the first one, God himself.102
I suggest that the objection fails due to the fallacy of the
accident. To discover that there is an immaterial first mover is
to discover God or some inferior immaterial substance as the
principle of motion, not as the principle of being. Even
supposing we agree that the immobile mover of the Physics is

100

See, e.g., In Boet. De Trin., q. 6, a. 3 (Leonine ed., 50:168, ll. 156-68).
IV Metaphys., lect. 1 (Marietti ed., 533). We saw this objection used by Wippel as
a motivation to look outside of natural philosophy for the grounding of metaphysical
separatio.
102
Wippel, “Metaphysics and separatio,” 89-90, 92-94, 104.
101

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431

indeed God,103 we still would not know him, at the end of the
Physics, under the aspect of cause of being, but under the aspect
of first mover. It is as if a highway patrolman pulled over a
wanted murderer for speeding; at first, he recognizes the culprit
only as breaking the highway code, but he accidentally stops a
murderer. When he investigates further, he is happy to uncover
the further predicate. In the case before us, we know the first
mover as such, and we prove that it is immaterial. Yet if the first
mover is indeed immaterial, we will know that the word
“being” can be extended to something beyond matter and that
there is a science beyond physics precisely because there is
something which cannot be explained by the principles of
physics, but which is itself the principle of physical
phenomena.104 We may, in our new science, go on to look for
the cause of the newly discovered subject, “being as such” or ens
commune, where we mean this to name something that extends
beyond material being. After this argument, we know that
metaphysics is not only possible, but necessary, and that its goal

103

As Wippel notes, this is a controverted claim; one might well think it is only able
to cause motion, that it is not intelligent, etc., in short, to grant it very little of our
common ideas about God. The argument only demands that we see it as an immaterial,
infinitely powerful mover. See ibid., 89 n. 52. The crucial point here, though, is that the
argument does demand that we see it as immaterial.
104
In Boet. De Trin., q. 5, a. 2, arg. and ad 3 (Leonine ed., 50:142, ll. 12-15; 144, ll.
138-50). In an exchange of articles, Mark Johnson and John Knasas debated the
interpretation of these texts. The final reply of Johnson seems to me definitive. John
Knasas, “Ad mentem Thomae: Does Natural Philosophy Prove God?”, Proceedings of the
American Catholic Philosophical Association 61 (1987), 209-20; idem, “Immateriality
and Metaphysics,” Angelicum 65 (1988), 44-76; Mark F. Johnson, “St. Thomas’s De
Trinitate, q. 5, a. 2 ad 3: A Reply To John Knasas,” The New Scholasticism 63 (1989):
58-65; John Knasas, “‘Does Natural Philosophy Prove the Immaterial?’: An Answer to
Mark Johnson,” American Catholic Philosophical Quarterly 64 (1990): 265-70; Mark F.
Johnson, “Does Natural Philosophy Prove the Immaterial?: A Rejoinder,” American
Catholic Philosophical Quarterly 65 (1991): 97-105; idem, “Immateriality and the
Domain of Thomistic Natural Philosophy,” The Modern Schoolman 67 (1990):
285-304.

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is to uncover the cause of being as such, which will turn out to
be God.105
In fact, not only can natural philosophy prove the existence
of immaterial beings, but only natural philosophy can do so.
The science of metaphysics presupposes their existence, as we
saw above. Furthermore, it seems that the study of immaterial
substances would have to be grounded in the study of some
other substances (since accidents have their principles in the
substances of which they are accidents),106 but the only other
substances available are the material ones treated in natural
philosophy. Thus, the only candidate for proving the existence
of immaterial substances, and so of any immaterial thing at all,
is natural philosophy.
A third objection is that, if St. Thomas really agreed with the
thesis of this essay, he ought to have said so somewhere,
especially as he explicitly discusses some other ways in which
metaphysics uses natural science in the commentary on
Boethius’s De Trinitate.107 A sufficient answer to this would
require a consideration of that text and of others, some of
which are dismissed on the grounds that they merely offer an
interpretation of Aristotle’s thought,108 which is supposedly
different from what is said in texts that indisputably present St.
Thomas’s own views.109 The texts in question must be dismissed
if the claim that metaphysics does not presuppose a proof from
natural philosophy of the existence of positively immaterial
being is to be supported: “If they [the disputed texts] do reflect
[St. Thomas’s] personal position, it will follow that for him the
existence of the science of being as being is contingent upon our
prior knowledge of the existence of separate entity.”110 In short,
105

Wippel grants that if such arguments are possible in natural philosophy, they
could be a road to metaphysics (Metaphysical Thought, 61-62).
106
See De Ente, c. 6 (Leonine ed., 43:380, ll. 50-58).
107
See esp. In Boet. De Trin., q. 5, a. 1, ad 9 (Leonine ed., 50:141, ll. 347-81). See
Wippel, “Metaphysics and separatio,” 97-98 and n. 73.
108
Wippel cites in particular the following texts: III Metaphys., lect. 6 (Marietti ed.,
398); IV Metaphys., lect. 5 (Marietti ed., 593); VI Metaphys., lect. 1 (Marietti ed.,
1170); and XI Metaphys., lect. 7 (Marietti ed., 2267).
109
Metaphys., pro.; In Boet. De Trin., q. 5, a. 4 (Leonine ed., 50:154, ll. 175-206).
110
Wippel, Metaphysical Thought, 58.

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there are, in fact, texts of St. Thomas that propose the
traditional understanding of the source of metaphysics.
Nevertheless, resolution of this textual disagreement could only
come by way of a close reading of both the undisputed and the
disputed texts and probably some others, and that is work for
another day.
CONCLUDING REFLECTIONS
The principle at work here is this: act is before potency. If
we are to come to know, the knowledge we seek must be based
on some actual pre-existent knowledge. The fundamental
problem for us as humans is that we are animals, and so the
proper objects of our minds are the whatnesses of material
things. For we must begin from what we know and go to what
we do not know, and what we know first is the natural object of
our mind. Because color is the proper object of sight, we see
everything else by way of seeing color, as we see a motion and a
shape and a man by seeing color. Following Aristotle, St.
Thomas says that the proper object of the human mind is the
quiddity of material things.111 If so, we cannot know anything
except by way of material things just as we cannot see anything
except by way of seeing color. We know everything we know
starting from those quiddities. Not only that, but just as we
must always keep before our minds the phantasms of things,112
so must we keep in mind the quiddities of material things.
Lacking these, we have no foothold in reality. Given, then, that
the quiddities of immaterial things are utterly different from the
quiddities of material things, and that all the names shared by
immaterial and material things are equivocal, even if analogous,
we will never get from one to the other by generalization,
abstraction, or simple judgment. Because the immaterial is
extrinsic to the material, we shall arrive at the immaterial only
111
112

STh I, q. 84, a. 7 (Leonine ed., 5:325).
Ibid.

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by arguments from extrinsic causes, that is, agent and final and
exemplar causes. To quote again a fundamental text, “our
intellect is not proportioned to knowing something by natural
knowledge except through sensibles; and therefore it is not able
to arrive at pure intelligibles except by arguing,”113 and, I add,
by arguing within natural philosophy.

113

I Sent., d. 3, q. 1, a. 2, ad 2 (Mandonnet, ed., 1:94): “sed intellectus noster non
est proportionatus ad cognoscendum naturali cognitione aliquid nisi per sensibilia; et
ideo in intelligibilia pura devenire non potest nisi argumentando.” See also STh I, q. 84,
a. 8 (Leonine ed., 5:328): “Omnia autem quae in praesenti statu intelligimus,
cognoscuntur a nobis per comparationem ad res sensibiles naturales” (“All things which
we understand in our present state are understood by us by comparison with natural
sensible things”).

The Thomist 84 (2020): 435-66

THE REUNIFICATION OF NATURALISM AND
PERSONALISM IN THE CONJUGAL ACT:
A CONTRIBUTION OF SERVAIS PINCKAERS
MICHELE M. SCHUMACHER
University of Fribourg
Fribourg, Switzerland

A

S SERVAIS PINCKAERS has shown in numerous contexts, the modern era is marked by a great irony: the
nominalist attempt to protect—as it were—divine
freedom from human freedom eventually led to the Sartrian
attempt to protect human freedom from the divine. In both cases,
nature—with its normative qualities—must be strictly denied.
For nominalism, nature represents a menace to the Creator’s
freedom whimsically to change his mind from one moment to the
next. For Sartrian existentialism, “there is no human nature, since
there is no God to conceive it.”1 Within this context, Christian
morality has been reduced, as Pinckaers observes, to the
“voluntary interaction between two freedoms.”2 As strictly
subhuman, nature is no longer considered as directive, or
normative, for human action, and by no means is it considered
transparent to the divine will or intentions. If, then, modern man
is to meet God as Lawgiver, it will be a meeting conducted
between spirits.

1

Jean-Paul Sartre, Existentialism and Human Emotions (New York: Philosophical
Library, 1957), 15. Similarly, “we remind man that there is no lawmaker other than
himself, and that in his forlornness he will decide by himself” (ibid., 50, 51).
2
Servais Pinckaers, Morality: The Catholic View, trans. Michael Sherwin (South Bend,
Ind.: St. Augustine’s Press, 2001), 34.
435

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MICHELE M. SCHUMACHER

Such a spiritualized view of morality is ascribed by the young
Joseph Ratzinger—as differing from the great champion of
nature, the more mature Ratzinger—to the Second Vatican
Council’s teaching with respect to marriage. Acting as a theological advisor to the archbishop of Cologne, the thirty-five-yearold Ratzinger reported that the council had “eliminated” the
“dual dowry” that antiquity had bestowed upon Christian ethics,
namely, “the procreative function of marriage and the habit of
judging ‘in accordance with nature’.” With respect to the first, it
had been commonly held that “the concept of end supplies the
basic norm for judging marital ethics.” With respect to the
second, it had been held that nature—precisely as the work of the
divine Logos—was charged with divine meaning and intention.
As if to challenge these criteria, which had been operative for at
least two millennia, the council—so the young Ratzinger
reported in his commentary—accorded a place to “neither the
concept of the ‘prime end of procreation’ nor the concept of
marital behavior ‘according to nature’.” Instead, he suggested
that
a moral teaching whose norms came “from below” (from a concept of nature
that was not all that unequivocal) was now supplanted by a teaching whose
norms came “from above,” from a spiritual view of marriage and family. And
so, the text [of Gaudium et Spes] points to conscience, to the Word of God, to
the Church interpreting the Word of God, as proper guides for morality in
marriage.3

In this way, Ratzinger suggested, the council opted to move
away from naturalism toward, or in favor of, Christian
personalism:
It is simply not the same, whether a person asks himself if his actions are “in
accord with nature” . . . [or whether, instead, he asks if] his actions are
responsible actions in view of other persons with whom he is related in the
marriage community, and whether his actions are responsible in view of the
Word of the personal God who has indicated the fundamental pattern of

3
Joseph Ratzinger, Theological Highlights of Vatican II, with introduction by Thomas
P. Rausch, trans. Henry Traub, Gerard C. Thormann, and Werner Barzel (New York:
Paulist Press, 1966), 237-39.

REUNIFICATION OF NATURALISM AND PERSONALISM

437

conjugal love by comparing it with love for the Church as exemplified in Christ
(Eph 5, 25-33).4

At issue was not so much the debate between the covenantal view
of marriage in the Scriptures and a juridical or contractual one.5
Rather, in keeping with the council’s high regard for human
freedom, emphasis was placed upon the challenge of uniting
human intentions with divine purposes. In the council’s own
words, “The intimate partnership of married life and love has
been established by the Creator and qualified by His laws,” while
being nonetheless “rooted in the conjugal covenant of irrevocable
personal consent.”6
As for the Creator’s “laws,” the young Ratzinger seems to
suggest that these cannot be simply equated with natural law in
the traditional sense of the term, such that nature’s inclinations
might be understood as prescriptive for moral action, including
the conjugal act. Within the specific context of “harmonizing
conjugal love with the responsible transmission of life,”7 it would
seem that equal regard could not possibly be granted to those
natural inclinations that man shares with the animals—“such as,”
St. Thomas specifies, “sexual intercourse, education of offspring
and so forth”—and those inclinations that are also natural, but
nonetheless proper to man: “according to the nature of his
reason,” such as the “natural inclination to know the truth about
God and to live in society.”8 After all, the “sexual characteristics
of man and the human faculty of reproduction wonderfully
exceed the dispositions of lower forms of life,” the council

4

Ibid., 239.
From the purely contractual perspective, John Ford argued, for example: “Even a
marriage in which there is no mutual help, no life in common, hatred instead of love, and
complete separation, both bodily and spiritually, remains a true marriage in the sense that
the essence of marriage is still there” (John Ford, “Marriage: Its Meaning and Purpose,”
Theological Studies 3 [1942], 333-74, at 348).
6
Gaudium et Spes, 48. Translations of the documents of the Second Vatican Council
are taken from Walter M. Abbott, S.J., The Documents of Vatican II (New York: Guild
Press, 1966).
7
Gaudium et Spes, 51.
8
STh I-II, q. 94, a. 2.
5

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MICHELE M. SCHUMACHER

recognized.9 Furthermore, it is “by our will that we employ
whatever powers we may have,” as St. Thomas points out.10 As
specific to man, reason and will are thus called upon—or so it is
reasoned by many interpreters of the teaching of the Second
Vatican Council—to dominate the natural inclinations: if not by
technical mastery,11 then by a personalistic consideration that
treats marital love as possibly the highest of the goods of marriage
or, at least, as the good from which other goods proceed.
At any rate, in what Theodore Mackin points to as a “seismic
shift in methodology,”12 the Second Vatican Council failed to
present procreation as the primary end of marriage and of the
marriage act, thereby vindicating the teaching of certain
personalist theologians, among whom figured, with a certain
prominence, Herbert Doms.13 These theologians argued—as
Ratzinger summarized nearly twenty years later—that “the classic
treatment of marriage in Canon law, based on its ‘ends’, did not

9

Gaudium et Spes, 51.
STh I, q. 5, a. 4, ad 3.
11
See Pope Paul VI, encyclical letter, Humanae Vitae (July 25, 1968), 17-18.
12
Theodore Mackin, What Is Marriage? Marriage in the Catholic Church (New York:
Paulist Press, 1982), 239.
13
See Herbert Doms, The Meaning of Marriage, trans. George Sayer (New York: Sheed
and Ward, 1939); originally Vom Sinn und Zweck der Ehe (Breslau: Ostdeutsche
Verlagsanstalt, 1935); and idem, “Amorces d’une conception personaliste du mariage
d’après S. Thomas,” Revue thomiste 45 (1939), 754-63. Doms was largely influenced by
the tradition of Dietrich von Hildebrand, who innovatively presents love as the primary
meaning of the conjugal act, while simultaneously admitting the traditional Augustinian
presentation of procreation as the primary end of marriage. (See Dietrich von Hildebrand,
Marriage: The Mystery of Faithful Love [Manchester, N.H.: Sophia Institute Press, 1984,
1991]; originally Die Ehe [Munich: Kösel-Pustet, 1929]). Doms breaks from this tradition
by abandoning the hierarchical language of ends and making the personal communion of
the couple—their “two-in-oneship” (Zweieinigkeit)—the primary end of marriage to
which all other ends are subordinate. For a thorough exposition of the differences
between Doms and Von Hildebrand and an excellent presentation of the rival positions
of theologians who identify themselves as personalists—those following Doms in denying
the primacy of procreation, and those following Hildebrand who holds to the primacy of
procreation as the end of marriage and the primacy of love as the meaning of marriage—
see John S. Grabowski, “Person or Nature? Rival Personalisms in 20th Century Catholic
Sexual Ethics,” Studia moralia 35 (1997): 283-312.
10

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do full justice to the essence of marriage.”14 They reasoned that
the notion of “end” fails to account for the particularly human
character of marriage—whence, one might add, the specific
relevance of the formulation of Humanae Vitae, in its preference
for the word “meaning,” or “significance” (significationem).15 “In
no way did these theologians [or the council, for that matter]
deny the importance of fecundity in the complex values of human
sexuality,” Ratzinger acknowledged, now as the head of the
Congregation for the Doctrine of the Faith. However, “they
assigned a new place to it within the framework of a more
personalistic perspective in the way of considering marriage,”
which represents, he admitted, a “significant deepening” of
Catholic doctrine. Nonetheless disturbing for Ratzinger was what

14
Joseph Ratzinger, The Ratzinger Report (San Francisco: Ignatius Press, 1985), 88. It
is worth noting that the new Code of Canon Law promulgated in 1983 was intended to
reflect the “substantial ‘novelty’ of the Second Vatican Council” (John Paul II, apostolic
constitution Sacrae Disciplinae Leges [January 25, 1983]). This included, as Luigi DeLuca
points out, a more personal understanding of marriage: one that “involves the integral,
reciprocal gift of two persons and not merely of two bodies” (Luigi DeLuca, “The New
Law of Marriage,” The Catholic Lawyer, 50 no. 1 [1985], 70-93, at 74). In contrast to
the 1917 code, which “reduced the object of marital consent . . . to the ‘handing over and
receiving of the right to the body for those acts which are per se apt for the generation of
offspring’”—whence the domination of “the remedy of concupiscence” in the Church’s
juridic teaching on marriage (ibid., 70)—the new code presents the spouses as, more
specifically, “‘giv[ing] and accept[ing] each other’ (Canon 1057 §2), [thereby] indicating
that there is an integral gift of oneself to the other” (ibid., 87). Furthermore, the new code
fails to mention the hierarchy of the ends of marriage, as did the 1917 code (ibid., 73).
See also Cormac Burke, “Marriage: A Personalist or an Institutional Understanding?”,
Communio 19 (1992), 278-304, at 283-85; and Mackin, What Is Marriage, 283-97.
15
See Pope Paul VI, Humanae Vitae 12. The word meaning “highlights the subjective
and psychological dimension. . . . ‘Meaning’ is born in consciousness with the rereading of
the (ontological) truth of the object. Through this rereading, the (ontological) truth enters,
so to speak into the cognitive, that is subjective and psychological dimension” (Pope John
Paul II, Man and Woman He Created Them: A Theology of the Body, trans. Michael
Waldstein [Boston: Pauline Books & Media, 2006], 620). Similarly, Karol Wojtyła points
out that “the objectivity of a right conscience allows the spouses to establish an authentic
harmony between what the conjugal act objectively ‘signifies’ (significa) and the ‘meaning’
(significato) that the spouses themselves attribute to it in their own inner attitude, in the
subjective action and in their intimate experience.” (Karol Wojtyła, “The Anthropological
Vision of Humanae Vitae,” trans. and introd. William May, Nova et vetera [Eng. ed.] 7
[2009]: 731-50, at 743).

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MICHELE M. SCHUMACHER

he observed in the wake of the council as “a new line of
development” opposing personalism and naturalism. In what
thus amounted to a reversal of his comments twenty years earlier,
Ratzinger noted that the council—in accord with “the constant
teaching of the Church”—did in fact point to “the internal order
and language of nature” as morally normative: “based on the
unity of person and nature in man.” However, he also noted that
“an exaggerated personalism” had led some theologians to reject
this internal order in favor of the subjective will of the person as
“the sole point of reference” for sexual and conjugal ethics. He
concluded that this is “one of the reasons that Humanae Vitae
was rejected.”16
In this way, the cardinal and future pope pointed to the
correspondence between the typically modern dialectic of person
and nature—a dialectic that arguably even he did not escape in
his original commentary on Gaudium et Spes, quoted above—
and the consequential rejection of the “inseparable connection,”
defined by Paul VI, “between the unitive significance and the
procreative significance” of the marital act.17 It seems that we
have not advanced an inch beyond the nominalist presumption
that nature is in no way prescriptive of the Creator’s intentions
for his creature. In the case at hand, the presumption is made that
the natural fertility cycle of the woman and the shared fertility of
the couple are not necessarily related to the Creator’s intention
for human persons, who are, after all, perfectly capable of
overruling nature’s dictates.

16

Ratzinger, Ratzinger Report, 88.
Pope Paul VI, Humanae Vitae 12: “nexu indissolubili . . . inter significationem
unitatis et significationem procreationis, quae ambae in actu coniugali insunt”. On the
personalist-naturalist debate, see Nicholas J. Healy, Jr., “Christian Personalism and the
Debate over the Nature and Ends of Marriage,” Communio 39 (2012): 186-200; Lisa
Cahill, “Catholic Sexual Ethics and the Dignity of the Person: A Double Message,”
Theological Studies 50 (1989): 120-50; Todd A. Salzman and Michael G. Lawler, The
Sexual Person: Toward a Renewed Catholic Anthropology (Washington, D.C.:
Georgetown University Press, 2008), 48-92; Burke, “Marriage: A Personalist or an
Institutional Understanding?”; José Granados, “The Body, the Family, and the Order of
Love: The Interpretive Key to Vatican II,” Communio 34 (2012): 201-22, especially
205-7.
17

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Such, I will argue, is a timely and highly significant example
of the pertinence of Pinckaers’s doctrine. Not only has he—
perhaps more than any contemporary moral theologian—alerted
us to the pervasive and highly divisive influence of nominalism,
he has also shown us how to overcome it in an effective way. In
so doing, he likewise points beyond the rivalry of the two ends
of the marital act, with procreation “stand[ing] for nature, with
its biological force and the moral obligations it imposes,” as he
puts it, and union “on the side of the person’s freedom and
sentiment of love, and also on the side of reason, which claims to
rule nature through knowledge.”18 Pointing beyond the “eitheror” option that typifies nominalist doctrine—either divine
freedom or human freedom, either naturalism or personalism,
either objectivity or subjectivity, either freedom or sensibility,
either freedom or law19—Pinckaers insists upon an integral
anthropology that implies the perfect harmony of naturalism and
personalism.
I. THE UNIFICATION OF NATURALISM AND PERSONALISM WITHIN
AN INTEGRAL ANTHROPOLOGY
The primary challenge at the heart of this divide between
naturalism and personalism, as Pinckaers diagnoses it, comes
from the consideration of nature and freedom as contraries.
If we think of freedom as something dependent only on our voluntary decision,
and totally indeterminate before we take that decision, then we will be led to
think of the natural as something necessarily predetermined. In this view, it is
hard to see how we can reconcile the natural and the free. We will see the
natural inclinations of both intellect and will as tendencies both blind and
coercive.20

Hence, for many of our contemporaries, it is considered the
highest level of freedom to resist nature and thus also (as befits
the “pro-choice” slogan, for example) to refuse what the
18
Servais Pinckaers, The Sources of Christian Ethics, 3d ed., trans. Sr. Mary Thomas
Noble (Washington, D.C.: The Catholic University of America Press, 1995), 445.
19
See ibid., 350-51.
20
Ibid., 400-401.

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MICHELE M. SCHUMACHER

Aristotelian tradition considered the highest natural perfection:
that of reproduction.
The most natural act [Aristotle teaches] is the production of another like itself,
an animal an animal, a plant a plant, in order that, as far as its nature allows, it
may partake in the eternal and divine. That is the goal towards which all things
strive. . . . Since then no living thing is able to partake in what is eternal and
divine by uninterrupted continuance, it tries to achieve that end in the only way
possible to it . . . so it remains not indeed as the self-same individual but
continues in something like itself—not numerically, but specifically one [that is
to say, of the same species].21

From this perspective it should not be surprising that St. Thomas
considers a thing “perfect when it can reproduce its like.”22 So
fundamental to nature is the inclination to generate—or in the
case of the human being, whose dignity supersedes other species,
to procreate—that the word nature, coming from natus (to be
born), has come to designate that which is handed on from
genitor to offspring, namely, as Marie-Joseph Nicolas observes,
“the essence of the species that is communicated by
generation.”23 Nature’s purpose is nonetheless “different as regards corruptible and incorruptible things,” St. Thomas argues.
Since—to draw upon Aristotle’s insight above—no corruptible
thing is everlasting, nor permanent “except in the species, it
follows that the chief purpose of nature is the good of the species;
for the preservation of which natural generation is ordained.”
When it comes to incorruptible substances, on the other hand,
they “survive, not only in the species, but also in the individual;

21
Aristotle, De Anima 2.4.415a28-415b3 (trans. J. A. Smith, in Richard McKeon, ed.,
The Basic Works of Aristotle [New York: Random House, 1941], 561).
22
STh I, q. 5, a. 4. Translations of the Summa theologiae are taken from the translation
by Laurence Shapcote, O.P., ed. John Mortensen and Enrique Alarcón, vols. 13-20 of the
Latin/English Edition of the Works of St. Thomas Aquinas [Lander, Wyo.: The Aquinas
Institute for the Study of Sacred Doctrine, 2012]). Cf. ScG I, c. 37.
23
Marie-Joseph Nicolas, “L’idée de nature dans la pensée de saint Thomas d’Aquin,”
Revue thomiste 74 (1974): 533-90 at 543: “Mais de l’idée dominante de ‘principe de
génération’, le mot ‘nature’ en est venu à désigner ce qui est la fin même de la génération,
c’est-à-dire l’essence de l’espèce qui se communique par la génération.” Cf. STh III, q. 2,
a. 1.

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wherefore even the individuals are included in the chief purpose
of nature.”24
Given what St. Thomas calls the “duplex natura”25 of the
human person—a nature that is at once physical and spiritual—
it follows, as Nicolas reasons, that
the intention of nature in human sexuality is not like that of animal sexuality to
safeguard the species: it is to procreate a human person, who is significant in
him- or herself (etiam individua sunt de principali intentione naturae), and
consequently to lead him or her to full stature and autonomy by means of
education.26

In the human species, in fact, the natural inclination to
reproduce—an inclination that is often but incorrectly understood as a purely biological impulse—necessarily includes the
inclination to educate one’s offspring: an inclination that engages
the entire personality of both parents and their progeny.27 As
Pinckaers puts it, “we are dealing with the bonum prolis, the good
of the child, with all that this includes, especially education, not
merely the generatio prolis, or generation.”28 In the confines of
the family and the home, children receive their primary moral,
religious, human, and social formation. It is there that they learn
their mother tongue and that they receive their primary religious
and moral formation, including such important lessons as the
difference between good and evil and how to live in society. It is
thus not surprising that Pinckaers recognizes human sexuality as
“naturally linked with our other inclinations, even the most
spiritual.”29

24

STh I, q. 98, a. 1.
“There is a twofold nature in man, rational nature, and the sensitive nature” (“in
homine est duplex natura, scilicet rationalis et sensitiva”) (STh I-II, q. 71, a. 2, ad 3).
26
Nicolas, “L’idée de nature dans la pensée de saint Thomas d’Aquin,” 571:
“l’intention de la nature dans la sexualité humaine n’est pas comme dans la sexualité
animale de sauvegarder l’espèce : elle est de procréer une personne humaine qui vaut par
elle-même (etiam individua sunt de principali intentione naturae), et par conséquent de la
mener jusqu’à sa pleine stature et autonomie par l’éducation.” Cf. ScG III, c. 122.
27
See the argument of St. Thomas in ScG III, c. 122.
28
Pinckaers, Sources of Christian Ethics, 446.
29
Ibid., 443.
25

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MICHELE M. SCHUMACHER

Nor should we be surprised that, as applied to man, the term
nature refers not only or primarily to that which we have in
common with other animals and thus to that which might be
contrasted with reason or to that which does not obey reason.
Instead, St. Thomas explains, in the case of man, nature
designates first of all intellect and reason inasmuch as they are
“the principal part of man’s nature, since in respect thereof he
has his own specific nature.” Hence, for example, it is “natural
to man to take pleasure in contemplating the truth and in doing
works of virtue.”30 In fact, Pinckaers recognizes the morality of
St. Thomas as rooted in “the natural inclination (of the spiritual
order) of the will towards the good,” the good, more specifically
“as it appears to reason.” Hence the “decisive moral question” is
“to know and to love the true good, to seek the true happiness.”31
Pinckaers suggests that the true good is more specifically the
good that is connatural to man and thus perfective of his dual
nature—a nature, it bears repeating, that is at once bodily and
spiritual and thus sensitive and rational. That is why, in fact, the
natural inclinations that the human person shares with other
corporeal beings are experienced by him or her in a unique—that
is to say, personal—manner. Only persons, after all, are capable
of “interioriz[ing]” these inclinations and of “freely orientat[ing]
them” in view of their own personal fulfillment.32 This means not
only that the lower inclinations—those of the sensitive appetites,
for example—are ordered by the rational inclination of the will.
It also means that they are, as St. Thomas explains, granted a
participation in human freedom.33
30

STh I-II, q. 31, a. 7. See also STh III, q. 18, a. 1, ad 3.
Servais Pinckaers, footnote 2 to STh I-II, q. 8, a. 1 (in Thomas d’Aquin, Somme
théologique II [Paris: Cerf, 1984], 80): “La morale de S. Thomas s’enracine donc dans
l’inclination naturelle (d’ordre spirituel) de la volonté vers le bien. . . . La question morale
décisive sera de connaître et d’aimer le vrai bien, de rechercher la vraie béatitude.”
32
International Theological Commission, “In Search of a Universal Ethic: A New Look
at the Natural Law” (2009), no. 63 (http://www.vatican.va/roman_curia/
congregations/cfaith/cti_documents/rc_con_cfaith_doc_20090520_legge-naturale_en.ht
ml).
33
Saint Thomas argues that in man the sensitive appetite “has a certain share of liberty,
in so far as it obeys reason” (STh I-II, q. 26, a. 1: “aliquid libertatis participat, inquantum
obedit rationi”).
31

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In fact, given the hylomorphic structure of our human nature,
we can, Pinckaers notes, “spontaneously move from the emotions
to the spiritual, and, on the contrary, the spiritual can rebound
through sensation, for good and for bad.”34 Because man is a
single substance, he is not, as thirteenth-century Augustinians
thought, composed of three souls, namely a vegetative soul, an
animal soul, and a spiritual one. Instead, Pinckaers says, he is “of
one single soul functioning vitally at these three levels as an
interior principle of unification and convergence.”35 As a
consequence, the passions might be said to participate in the
virtue proper to the spirit. It is only “reasonable,” Pinckaers
argues—by “application of hylomorphism to the moral order”—
“that a virtue-centered morality consists precisely in the
integration of feelings in the virtuous person.”36 Such is what
Marie-Dominique Chenu calls “an intimate penetration” of the
spirit in the passions (wherein it is said to be “at home”),37 or
what the International Theological Commission calls “emotional
intelligence.”38 Virtue cannot even exist in us, Pinckaers
maintains, “without the participation of our senses and even our
bodies.”39 That is why the Catechism of the Catholic Church
follows St. Thomas in presenting moral perfection as
“consist[ing] in man’s being moved to the good not by his will
alone, but also by his sensitive appetite.”40

34
Servais Pinckaers, “Reappropriating Aquinas’s Account of the Passions,” in The
Pinckaers Reader: Renewing Thomistic Moral Theology, ed. John Berkman and Craig
Steven Titus (Washington, D.C.: The Catholic University of America Press, 2005), 273387, at 278.
35
Pinckaers, Sources of Christian Ethics, 438; cf. ScG IV, c. 81.
36
Servais Pinckaers, Passions and Virtue, trans. Benedict M. Guevin (Washington
D.C.: The Catholic University of Amercia Press, 2015), 2. See the excellent exposition by
Paul Gondreau, “The Passions and the Moral Life: Appreciating the Originality of
Aquinas,” The Thomist 71 (2007): 419-50.
37
Marie-Dominique Chenu, “Les passions vertueuses: L’anthropologie de saint
Thomas,” Revue philosophique du Louvaine 13 (1974): 11-18, at 16: “par une pénétration
intime grâce à laquelle l’esprit est chez lui dans les sensibilités.”
38
International Theological Commission, “In Search of a Universal Ethic,” 57.
39
Pinckaers, Passions and Virtue, ix.
40
Catechism of the Catholic Church 1770; cf. STh I-II, q. 24, a. 3.

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MICHELE M. SCHUMACHER

Indeed, “unless we accept the fact that natural inclinations
penetrate to the heart of our free will and stand at the origin of
our actions,” we cannot admit “a real rootedness” of sexuality in
the human personality. The sexual inclination of the human
being so differs from that of the animals that Pinckaers does not
hesitate to refer to the specifically “human and moral dimension
of sexuality,” which in turn he recognizes as providing a special
basis for the fulfilment of the commandment to love our
neighbor: a commandment that “expresses one of the principles
of our free, spiritual fruitfulness.”41 As if to foreshadow the
Catechism’s presentation of human sexuality as “affect[ing] all
aspects of the human person in the unity of his body and soul”—
namely, “affectivity, the capacity to love and to procreate, and in
a more general way the aptitude for forming bonds of
communion with others”42—Pinckaers argues that “human
sexuality,” like human nature in general, “has a psychological,
moral, and even spiritual aspect.”43
To be sure, he admits, the biological drive to preserve and
foster life is a “characteristic feature” of the sexual inclination of
human persons, but this does not preclude the fact that the same
inclination “engages the entire personality through the bonds of
affection.” From this comes the distinction between the two ends
of marriage and of the marital act, the procreative and the
unitive, which are recognized as “naturally aid[ing] each other.”44
Indeed, far from conflicting with one another, these two ends are
recognized by Pinckaers as “converging,”45 with our biological
dimension being “vitally integrated” in our spiritual nature.46 It
is thus not surprising that, as applied to human persons, the
natural inclination to sexual union and the rearing of offspring
41

Pinckaers, Sources of Christian Ethics, 441-42.
CCC 2332.
43
Pinckaers, Sources of Christian Ethics, 441.
44
Pinckaers, Morality, 103, 104.
45
Pinckaers, Sources of Christian Ethics, 445.
46
Ibid., 441. Hence this inclination is called natural “not in the sense of a compelling
force, but rather in the sense of an inclination realized with the help of free will.” This
means that “we are beyond the biological and moving into the human and moral plane,
which includes the biological” (ibid., 445).
42

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may be regarded as “the inclination to marriage”47 and that this
inclination is acknowledged as that with which “our other natural
inclinations converge.” Hence, for example, Pinckaers recognizes
the inclination to self-preservation as being “reinforced” not only
by the experience of being “two in one flesh,” whereby they are
“enabled to give existence to other beings like themselves” but
also the experience of mutual support whereby “their capacity
for action and their concern for self-defense grow and
intensify.”48 In fact, the inclination to self-preservation “is
capable of redoubling its potential” in spiritual beings, Pinckaers
argues, in virtue of the love of friendship, whereby we seek the
preservation and well-being of the other as well as ourselves.49
As for the inclination to live in society, it “finds its first, most
natural, and in a sense most complete realization in marriage.”
After all, one might discover in the mutual support of spouses
and in the natural bond between parents and children what
Pinckaers points to as “the primitive types” of social relationships and even “paradigms” of the most basic forms of
government. So too the inclination to truth is fostered, he argues,
by the mutual love that opens the way to a deeper self-knowledge
that is likewise sustained by the experience of the difference and
complementarity of the sexes, not only on the biological level,
but also on the psychological.50 In short, “human sexuality is
naturally linked with our other inclinations, even the most
spiritual, and is in fact necessary if the latter are to find true
fulfillment in the realities of life.”51

47

Ibid., 441.
Ibid., 442.
49
Ibid., 425.
50
Ibid., 442-43.
51
Ibid., 443.
48

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MICHELE M. SCHUMACHER

II. THE PRIMORDIAL INCLINATION TO THE GOOD:
AN INCLINATION TO PERFECTION THAT UNIFIES THE VARIOUS
NATURAL INCLINATIONS
Beyond the unity, assured by our hylomorphic nature, of all
our natural inclinations—not only those that are proper to us as
human, but also those that we share with the other animals, and
even those that we share with all natural beings—Pinckaers
recognizes still another source of unity: a common rootedness of
the natural inclinations in the fundamental inclination to
goodness and truth. In fact, although Pinckaers admits that it is
legitimate and even necessary at times to distinguish the various
natural inclinations belonging to the human person, “we must
never forget to regroup them again in a dynamic synthesis.”
Together they “form a sheaf of closely linked yearnings and
energies,” and “they act only together, as members of an organism.”52 That is why the “humanization” of our natural inclinations does not entail “a violence done to them,” as the
International Theological Commission explains.53
Of course, this is not to deny—as Pinckaers readily admits—
that the human being, like other beings with sensation, might also
be naturally inclined away from what is evil or dangerous.
However, “the movement from within tends to what is suitable
more than it recedes from that which is unsuitable,” St. Thomas
argues.54 Hence “the inclination of the appetitive power is, of
itself, more eager in tending to pleasure than in shunning
sorrow.”55 As if to echo the Catechism’s presentation of love as
“the most fundamental passion . . . aroused by the attraction of
the good,”56 and St. Thomas’s presentation of love as “a first
cause,”57 Pinckaers emphasizes the fact that love of the good (as
inseparable from love of truth) is primary with regard to all other
inclinations of natural law:
52

Ibid., 452.
International Theological Commission, “In Search of a Universal Ethic,” 79.
54
STh I-II, q. 35, a. 6, ad 2.
55
STh I-II, q. 35, a. 6.
56
CCC 1765.
57
STh I-II, q. 28, a. 6.
53

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Saint Thomas somewhat clarifies the natural foundation of volition by saying
that the will spontaneously seeks not only the good in itself, but also all that is
appropriate to human nature, including objects proper to all its faculties
considered good. We spontaneously will truth, being and life, and all that is
necessary to maintain it, and so on. From this derive the various precepts of
natural law.58 . . . Let us note, however, that from this point of view, desire of
the good is primary, with the love of truth and of the conservation of being
appearing as kinds of goods, but inseparable from the love of the good.59

In short, the inclination to the good is a fundamental—or
“primitive”—instinct that is perhaps best described by the
spontaneous attraction that it causes in us.60 As such, it should
not be understood as an inclination following upon knowledge—
whether of a sensitive or of an intellectual nature—but as one
that is still more fundamental: a natural, innate desire which is
primary and foundational with respect to every elicited desire,
expressing the Creator’s rights over the creature. As such it also
conditions all of our inclinations, including those that are of a
spiritual nature. In fact, Pinckaers presents the fundamental
human inclination to goodness and truth as “superior” to even
the human will and reason, since it provides a “certain light which
inspires and clarifies all of their endeavors.”61 Englobing and
58

Cf. STh I-II, q. 94, a. 2.
Servais Pinckaers, “Appendice I: Notes explicatives,” in Thomas d’Aquin, Somme
théologique, I-II, qu. 6-17: Les actes humains, vol. 1, trans. Henri-Dominique Gardeil and
Servais Pinckaers (Editions de la Revue des jeunes), nouvelle édition (Paris: Cerf, 1997),
331: “S. Thomas précise quelque peu le fondement naturel du vouloir en disant que la
volonté recherche spontanément, non seulement le bien en soi, mais aussi tout ce qui
convient à la nature humaine, notamment les objets propres de toutes ses facultés
considérés comme bons. Nous voulons spontanément la vérité, l’être et la vie, et tout ce
qui est nécessaire pour l'entretenir, etc. De là découlent les différents préceptes de la loi
naturelle. . . . Notons cependant que le vouloir du bien est premier, de ce point de vue,
l’amour de la vérité et de la conservation dans l'être apparaissant comme des sortes de
biens, mais indissociables de l'amour du bien.”
60
Pinckaers, Morality, 99.
61
Pinckaers, footnote to STh I-II, q. 19, a. 1, in Thomas d’Aquin, Somme théologique,
tome 2 (Paris: Cerf, 1984), 90. This rich passage merits being quoted in its entirety: “The
natural inclinations to good and truth are therefore not inferior to reason and free will,
like pieces of blind and crude nature inserted therein, but are superior to them, like a
certain spiritual spontaneity and light that inspires and illuminates all their endeavors”
(“Les inclinations naturelles au bien et à la vérité ne sont donc pas inférieures à la raison
et à la volonté libre, comme des morceaux de nature aveugle et brute insérés en elles, mais
59

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MICHELE M. SCHUMACHER

gathering all of the other natural inclinations together “into one
dynamic stream,”62 this most basic of all of our natural
inclinations simultaneously assures their “profound harmony”
with “the quest for the good in the free will and of the truth by
reason.”63
Such is the overwhelmingly positive tenor of the foundation
of Pinckaers’s doctrine of freedom and natural law. Unlike a
nominalist conception of freedom—freedom exercised in the
absence of any force of attraction or repulsion, whence its designation as “freedom of indifference”—Pinckaers’s understanding
of freedom implies the “thrust toward excellence,” or perfection,
which he qualifies as one of freedom’s most “essential
feature[s].”64 The good that impels us is proper, or connatural, to
us:65 it cannot be reduced to simply a biological good, nor, on the
other hand, to a good that would exclude the biological
dimension, which is, after all, likewise proper to human nature.
It follows that the specific good of the human person will not
consist in “a preformed idea in which [human] action should be
cast as in a mold, nor in a pre-established plan that only needs to
be followed and implemented.” Instead, Pinckaers suggests, it
should be understood as “the fullness befitting a being capable of
producing his own action, of drawing from himself [as an
incarnate nature], of inventing and creating, in some way, his
action and his perfection.”66 That is why we cannot simply

elles leur sont supérieures, comme une certaine spontanéité spirituelle et une lumière qui
inspirent et éclairent toutes leurs démarches”).
62
Pinckaers, Morality, 98.
63
Pinckaers, footnote to STh I-II, q. 19, a. 1, in Thomas d’Aquin, Somme théologique,
2:90: “Ainsi les inclinations naturelles sont-elles en harmonie profonde avec la quête du
bien dans la volonté libre et de la vérité par la raison.”
64
Pinckaers, Sources of Christian Ethics, 412.
65
See STh I-II, q. 26, a. 1.
66
Pinckaers, “Appendice I: Notes explicatives,” in Thomas d’Aquin, Somme
théologique, I-II, qu. 6-17: Les actes humains, vol. II, translation, notes and appendix by
Servais Pinckaers (Editions de la Revue des jeunes) (Paris: Cerf, 1997), 164: “le bien ne
consiste pas dans une idée préformée où l'action devrait se couler comme dans un moule,
ni dans un plan préétabli qu'il suffirait de suivre et d'appliquer. Elle est la plénitude
convenant à un être capable de produire son action par lui-même, de tirer de soi,
d’inventer et de créer, en quelque façon, son agir et sa perfection.”

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transpose physical and biological accounts of goodness or health
to the moral plane.67 In fact, Pinckaers proposes that the
challenge of overcoming the destructive influence of nominalism
upon both anthropology and morality entails the rediscovery of
a spiritual nature “which does not oppose human freedom but
lies at its origin and forms it.”68
Our “instinct” for truth and goodness differs radically from
the animal instinct that is most readily associated with the term,
namely, “impulses of a lower order” which exist on “the
psychosomatic plane” and which pose “the most insidious threat
to the freedom and morality of actions” in virtue of a certain
determinism.69 To be still more specific, these spiritual
inclinations—inclinations that St. Thomas collectively refers to as
“rational instinct” (instinctus rationis) because they are proper to
man—are not directed in the same “determined and compelling
way” as are, for example, the biological inclinations of hunger or
thirst.70 They are nonetheless analogous to these biological
inclinations, which serve human freedom by preserving and
fostering human life. The spiritual inclinations to goodness,
truth, and happiness serve human freedom still more directly: by
acting as “intimate springs that water the human heart and
mind.”71 In this way they are said to “cause and increase freedom
at its very source.”72 Far from infringing upon our free
determination, as a nominalist understanding would have us
believe, these primitive spiritual inclinations impelling us to seek
67

See ibid., 2:165.
Pinckaers, Sources of Christian Ethics, 402.
69
Ibid., 333. Similarly, “All natural inclinations, summed up in the inclination toward
good or happiness, were thus subject to choice and to the will’s free determination. It was
as though they were uprooted from the will’s depths, to be placed before it, beneath it,
and subject to its choice. They were no longer a part of the essence of freedom” (ibid).
70
Ibid., 404. See also ibid., 385; and Servais Pinckaers, “L’instinct et l’Esprit au cœur
de l’éthique chrétienne,” in Carol-Josaphat Pinto de Oliveira, ed., Novitas et veritas vitae:
Aux sources du renouveau de la morale chrétienne. Mélanges offerts au Professeur Servais
Pinckaers à l’occasion de son 65e anniversaire (Paris: Cerf; Fribourg, Switzerland: Editions
Universitaires Fribourg, 1991), 213-23, at 221-22.
71
Pinckaers, Morality, 96.
72
Pinckaers, Sources of Christian Ethics, 401-2. Similarly, “Spiritual inclinations in no
way limit freedom but rather incite and develop it” (ibid., 404).
68

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truth and embrace goodness—including, most especially, the
truth concerning the good proper to man—are in fact “intimate
determinations that liberate us.”73 In fact, from the Thomistic
perspective, the natural desire for happiness is said to be causal
with regard to all other human desires.74
As for natural law, which Pinckaers presents as “the expression of our natural inclinations, especially the spiritual ones,”
it is thus “an inner law,” penetrating “to the heart of our freedom
and personality to show us the demands of truth and goodness.”75
That is why it operates by attraction rather than constraint,76 and
is realized in the evangelical law that Pinckaers characterizes as a
“law of freedom.”77 To be sure, the moral good discerned by
reason “imposes itself,” assuming a certain “character of
obligation and of law,” as the International Theological
Commission recognizes in a document that might well have been
inspired by Pinckaers.78 This obligation is hardly one that follows
upon an arbitrarily imposed moral imperative, however. On the
contrary, it follows “the law of one’s being,”79 since—it bears
repeating—its precepts are ordered according to man’s natural
inclinations,80 including the inclination to sexual intercourse and
the educating of offspring, and not excluding the spiritual
inclination to goodness, truth, and beatitude. It is, in fact, these
transcendental realities that order all of the natural inclinations
toward the good that define man as such.
The natural human “desire for the good and for beatitude” is
said by Pinckaers actually to gather “within itself all the natural
73

Ibid., 404.
“Every man naturally wills happiness: and all other desires are caused by this natural
desire” (STh I, q. 60, a. 2).
75
Pinckaers, Sources of Christian Ethics, 452. See also ibid., 405.
76
See, for example, Pinckaers, Morality, 97. Similarly, Pinckaers presents “a morality
of attraction, not obligation” (Sources of Christian Ethics, 359).
77
Pinckaers, Sources of Christian Ethics, 185.
78
International Theological Commission, “In Search of a Universal Ethic,” 43. “The
good is more than a duty,” Pinckaers insists. “It signifies a quality, a perfection that
attracts and causes our love” (Morality, 99).
79
International Theological Commission, “In Search of a Universal Ethic,” 43.
80
“Wherefore according to the order of natural inclinations, is the order of the
precepts of the natural law” (STh I-II, q. 94, a. 2).
74

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inclinations”—those that we share with animals and with other
living beings and those that are proper to us as spiritual
creatures—and to trace “in its development, the trajectory of
ordering to the final end”: that is to say, the end that defines us
as human, as creatures made in God’s image for the purpose of
being further likened to him.81 After all, as St. Thomas reasons,
“every inclination is to something like and suitable to the thing
inclined.”82 Hence, as Pope John Paul II puts it in an insight that
might also have been inspired by Pinckaers, “natural inclinations
take on moral relevance only insofar as they refer to the human
person and his authentic fulfilment, a fulfilment which for that
matter can take place always and only in human nature.”83 The
term of a natural inclination is not so much the thing or the object
that attracts, therefore, as the being or the subject that is
perfected thereby: “not knowledge, but being knowledgeable;
not the good, but being good.”84
Natural law is thus “law,” Pinckaers explains, because it spurs
the moral agent to act in accord with the dynamism of his own
nature: a dynamism—it bears repeating—that cannot simply be
reduced to certain biological tendencies (a common, but
unjustified reproach against Catholic moral teaching, especially
in matters of sexuality).85 In fact, Pinckaers follows St. Thomas
in presenting the good proper to the human person in a
“maximalist” sense: “in line with man’s tendency towards his full
development through a constant effort to be the best he can be.”86
“Good” is understood in the sense of “perfection,” for, in St.
81
Servais Pinckaers, “Aquinas on Nature and the Supernatural,” trans. Sr. Mary
Thomas Noble, in Berkman and Titus, eds., Pinckaers Reader, 359-68, at 363.
82
STh I-II, q. 8, a. 1: “Nihil autem inclinator nisi in aliquid simile et conveniens.”
83
Pope John Paul II, encyclical letter Veritatis Splendor (August 6, 1993), 50.
84
Jean-Hervé Nicolas, footnote to STh I, q. 5, a. 5, in Thomas d’Aquin, Somme
théologique, tome I (Paris: Cerf, 1984), 187: “le terme du mouvement appétitif est non
pas précisément la chose même qui attire, mais l’étant lui-même, rendu parfait par elle:
non pas la science, mais être savant; non pas le bien, mais être bon.”
85
See the acknowledgement and refutation of this argument by Pope John Paul II in
Veritatis Splendor, 46-50.
86
Pinckaers, “Appendice I: Notes explicatives,” in Thomas d’Aquin, Somme
théologique, I-II, qu. 6-17: Les actes humains, 2:164: “dans la ligne de la tendance de
l'homme vers son plein épanouissement par un effort constant vers le plus être.”

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Thomas’s own words, “by nature, the good of each thing is its act
and perfection,”87 and “every being seeks in its own way its
perfection, which is each one’s good.”88
As for the good proper to man, it will necessarily entail the
good of body and of soul, that is, of both the corporal and
spiritual dimensions that define him. Hence, natural law “refers
to man’s proper and primordial nature, the ‘nature of the human
person’, which is the person himself in the unity of soul and body,
in the unity of his spiritual and biological inclinations and of all
the other specific characteristics necessary for the pursuit of his
end.”89
III. PROCREATION AS A SPECIAL FORM OF MAN’S
COLLABORATION IN GOD’S CREATIVE WORK
Because “freedom for excellence”—as Pinckaers dubs St.
Thomas’s own understanding of freedom—is activated by the
natural desire for the good, which in turn exercises an attraction
that is binding only to the extent that it is absolute, Pinckaers
ultimately points the way to a noncompetitive conception of
divine and human causality. Indeed, he does not hesitate to refer
to human freedom as “the point of contact between the action of
God in man and properly human action.”90 It is thus possible to
speak of a “participated theonomy,” whereby man interiorizes
and interprets his natural inclinations, which he recognizes as the
expression of “creative wisdom,” so as in turn to apply them “as
fundamental norms” of his moral action.91
Such, as we have seen, is the natural law, properly speaking.
Because in fact “all the things to which man has a natural
inclination are naturally apprehended by reason as being good,
and consequently as objects of pursuit, and their contraries as

87

ScG I, c. 37.
Comp. Theol. 1.113. Similarly, “goodness signifies perfection which is desirable;
and consequently of ultimate perfection” (STh I, q. 5, a. 1, ad 1).
89
Pope John Paul II, Veritatis Splendor, 50.
90
Pinckaers, Sources of Christian Ethics, 380.
91
International Theological Commission, “In Search of a Universal Ethic,” 63.
88

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evil, and objects of avoidance,”92 knowledge of the good is
ordered according to man’s natural inclination rather than the
other way around, as is often thought to be the case.93 It is not
simply as a matter of course, therefore, that St. Thomas
recognizes reason following the lead of natural inclinations,
which the ancients called “seeds of virtue” (semina virtutum).94
Instead he assumes that the natural inclinations serve the
perfection of their subject, precisely because they are the work of
the Creator in the creature, drawing it to the end that not only
suits, or befits it, but even completes, fulfills, and actualizes it.95
As St. Thomas puts it, the “good of order existing in things
created,” and thus the order of inclinations to nature-specified
ends, “is itself created by God.”96 Because, moreover, as the
Angelic Doctor also teaches, “whatever is according to nature is
ordered by the Divine Reason, which human reason ought to
imitate,”97 nature is recognized by Pinckaers as a sort of school
“where man can learn to act with perfection, in imitation of
God.”98 Such is also the origin of the Thomistic analogy between
natural and voluntary actions, with the good at the origin of our

92

STh I-II, q. 94, a. 2.
See Rupert Johannes Mayer, “Zum desiderium naturale visionis Dei nach Johannes
Duns Scotus und Thomas de Vio Cajetan: Eine Anmerkung zum Denken Henri de
Lubacs,” Angelicum 85 (2008): 737-63, at 757.
94
See, for example, Pinckaers, “Aquinas on Nature and the Supernatural,” 362; and
Pinckaers, Sources of Christian Ethics, 334, 439, 452.
95
Pinckaers argues that “St. Thomas does not treat the passions in the Summa
[theologiae] as a physiologist, nor a psychologist, nor as a pure philosopher, but as a
theologian; because while remaining on the level of the senses, where he meets the
psychologist, he aims beyond, to man’s relation with God, as his true beatitude” (“Dans
la Somme, S. Thomas ne traite donc pas des passions en physiologiste, ni en psychologue,
ni en pur philosophe, mais en théologien, car, tout en se maintenant au niveau de la
sensibilité, où il rencontre le psychologue, sa visée s’étend au-delà, vers les relations de
l’homme avec Dieu, comme sa véritable béatitude”) (Servais Pinckaers, “Les passions et la
morale,” Revue des sciences philosophique et théologique 74 [1990]: 379-92, at 382).
96
STh I, q. 22, a. 1.
97
STh II-II, q. 130, a. 1.
98
Pinckaers, “Appendice I: Notes explicatives,” in Thomas d’Aquin, Somme
théologique, I-II, qu. 6-17: Les actes humaines, 1:329: “La nature devient alors comme
l’école où l’homme peut apprendre à agir en perfection, à l’imitation de Dieu.”
93

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voluntary actions being compared to the God-given form at the
origin of our natural actions.99
We should not be surprised, then, that Pinckaers understands
the demands of natural law as having “their source both in God
and in our human nature.”100 After all, St. Thomas maintains that
the “Divine intellect, which is the Author of nature, adjusted
delights to operations on account of the operations.” This means,
for example, that sexual intercourse is pleasurable, precisely
because God wants us to procreate, in view of the great good
(bonum excellens) of the preservation of the human species.101
That is also why “there is the greatest necessity,” St. Thomas
argues, “for observing the order of reason in this matter: so that
if anything be done in this connection against the dictate of
reason’s ordering it will be a sin.”102 Observance of the order of
reason is not achieved in the absence of our spiritual inclinations
toward truth and goodness, therefore, which touch “the essence
of our personality in our longing for happiness and love.” These
too, Pinckaers argues, are “the work of God . . . [who] conforms
the human person to the likeness of his wisdom and goodness,
and, as an interior master, calls him to participate more deeply in
his created freedom.”103 When, on the other hand, man “follows
the inclinations of his sensitive nature against the order of his
reason”104 or willingly acts “in opposition to the order established
in general throughout natural things,” he is said by St. Thomas to
99
“Just as a natural thing has its species from its form, so an action has its species from
its object, as movement from its term. And therefore just as the primary goodness of a
natural thing is derived from its form, which gives it its species, so the primary goodness
of a moral action is derived from its suitable object. . . . And just as, in natural things, the
primary evil is when a generated thing does not realize its specific form . . . so the primary
evil in moral actions is that which is from the object, for instance, to take what belongs to
another” (STh I-II, q. 18, a. 2). See also Comp. Theol. 1.113.
100
Pinckaers, Sources of Christian Ethics, 452.
101
See STh II-II, q. 153, a. 2; and q. 142, a. 1. Not surprisingly then, the Catechism
cites Pius XII’s teaching that it is in accord with the Creator’s intention that “spouses
should experience pleasure and enjoyment of body and spirit” in the sexual act (CCC
2362).
102
STh II-II, q. 153, a. 3.
103
Pinckaers, Morality, 70-71.
104
STh I-II, q. 71, a. 2, ad 3.

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act viciously and sinfully.105 The moral value of actions is thus
judged according to the conformity of human freedom with the
authentic human good.106
In this way, Pinckaers calls upon the teaching of St. Thomas
to point us beyond the nominalist opposition between human
freedom and divine freedom, as it was played out throughout
much of the modern era in the opposition between freedom and
necessity, or between person and nature. Following St. Thomas,
Pinckaers insists upon the unity of human reason and divine
reason. To argue, as they both do, that the inclination to truth
underlies our reasoned choices and our willed acts, means that
we are capable of grasping the meaning of things within a created
order, so as to be likewise capable of seizing thereby the divine
ratio: God’s intentions for his creatures, including human beings.
After all, in virtue of our senses and intellects, we are capable of
receiving the species of other things. Furthermore, although we
can only attain to particular goods with our senses, we can
apprehend the universal good with the intellect.107 Because, in
fact, the human soul is capable of receiving the form of other
beings, it is “in a way, all things,” and is even said by St. Thomas
to “approach to a likeness to God in Whom all things preexist.”108 For this same reason, the human person is, as the
International Theological Commission specifies, “capable of
freely interiorizing the divine intentions manifested in the nature
of things” and of formulating them “for himself under the form
of a moral law that inspires and orientates his action.”109 Human

105
STh II-II, q. 130, a. 1. See also STh I-II, q. 94, a. 3, ad 2. Similarly, “When therefore
an action proceeds from a natural force, in accord with the natural inclination to an end,
then the action is said to be right; since the mean does not exceed its limits, viz., the action
does not swerve from the order of its active principle to the end. But when an action
strays from this rectitude, it comes under the notion of sin” (STh I-II, q. 21, a. 1).
106
See Pope John Paul II, Vertitatis Splendor, 72.
107
Hence, “we should form our estimate of things not simply according to the order
of the sensitive appetite,” St. Thomas reasons, “but rather according to the order of the
intellectual appetite” (STh I-II, q. 4, a. 3).
108
STh I, q. 80, a. 2 (emphasis added).
109
International Theological Commission, “In Search of a Universal Ethic,” 70.

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reason is therefore, as Jean-Pierre Torrell would have it, “the
resting place of the divine design for man.”110
This means, of course, that the end of our actions is not—and
Pinckaers insists upon the point—something “to be left to the
whim of the person acting.” On the contrary, the morality of
human actions is judged by the congruity between human
purposes and divine intentions—between, on the one hand, “the
pole of orientation” of man’s “intentions and through them of
his external actions” and, on the other hand, “the ultimate,
objective and true end of man,” as defined by his created
nature.111 After all, it is in virtue of this nature that we are capable
of grasping God’s purpose, intention, or meaning for our lives
and for each of our powers—whence the distinction between end
and object112—and thus of willfully acting as cooperating causes
in bringing these to fulfilment.
Drawing attention to the richness of the vocabulary of St.
Thomas when he addresses the goodness of human acts,
Pinckaers points out that their perfection and plenitude might be
said to accord with “the language of Genesis,” when the Lord
declares “good” the various works of his creation (Gen 1:12, 18,
21, 25, 31). Unlike the poverty of moral language today, wherein
the “good” is understood in minimalist terms—namely, as that
which is nothing more than licit—Pinckaers promotes a morality
that is profoundly dynamic, with the “good” designating the
110
Jean-Pierre Torrell, St. Thomas Aquinas, vol. 2, Spiritual Master, trans. Robert
Royal (Washington, D.C.: The Catholic University of America Press, 2003), 261.
111
Servais Pinckaers, Le renouveau de la morale: Etudes pour une morale fidèle à ses
sources et à sa mission présente, with preface by Marie-Dominique Chenu (Paris: Téqui,
1978), 138.
112
Pinckaers explains that “end” is proper to the will, whereas “object” is proper to
each of the human faculties as its principle of actualization. Hence, for example, the
proper object of the intelligence is truth, whereas the object of the sensitive appetite is the
sensitive good. “The will, on the other hand, has as its proper object the good in itself,
which, not yet being possessed, becomes the reason for the end to be pursued; and it can
therefore be said that the end is the proper object of the will” (“L’intelligence a pour objet
propre le vrai, l'appétit sensible, le bien sensible, et les forces corporelles, l'œuvre
physique. La volonté, elle, a pour objet propre le bien en soi, qui, n'étant pas encore
possédé, prend raison de fin à poursuivre; aussi peut-on dire que la fin est l'objet propre
de la volonté”) (ibid., 132).

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plentitude sought by and befitting man: a plenitude that is
necessarily ontological before it is moral, and moral because it is
ontological.113 In fact, as Pinckaers’s confrere Michel Labourdette
explains, “every form, every nature in the universe, has its
appetite, that is to say, its inclination to be and to be better, to
attain that for which it was made: that in which it finds its full
actuality, its best state.”114
As for the spiritual creature, he is, Pinckaers explains, a
“receiver of the metaphysical good in this world,” which he
“transforms through his actions, as it were, into the moral
good.”115 In so doing, he is caught up in “the very dynamism of
the divine action which creates and governs.”116 Hence, human
actions and the whole visible cosmos that they order and exploit
are “like ‘steps’” along the way of our return (reditus) to God—
113
See Pinckaers, footnote 3 to STh I-II, q. 18, a. 1, in Thomas d’Aquin, Somme
théologique 2:136. The “tragedy” of the nominalist understanding of freedom in terms of
indifference, in contrast, is that it “turns away from spiritual interiority and from the life
that flows from it as a vital yearning for truth, goodness, and happiness” (Pinckaers,
Morality, 97).
114
Michel Labourdette, Cours de théologie morale I: Morale fondamentale (Paris:
Parole et silence, 2018), 83: “Toute forme, toute nature dans l’univers, a son appétit,
c’est-à-dire son inclination à être et à mieux être, à atteindre ce pour quoi elle est faite, en
quoi elle trouvera sa plus haute actualité, son meilleur état.” Hence, between the moment
in which a corporal being simply “is” and the moment in which it is “achieved in being,”
or perfected, there is, as it were—Jean-Hervé Nicolas explains of the perspective of St.
Thomas—a certain “interval” during which it is moved towards its proper perfection by
way of its own operations or actions. In virtue of these and of the acquisitions obtained
thereby, a being develops its natural potentialities, rooted within the natural form
whereby each being “is what it is” and whereby it is simultaneously disposed “to become
perfect in the line of what it already is” (Jean-Hervé Nicolas, footnote 1 to STh I, q. 5, a.
1, in Thomas d’Aquin, Somme théologique 1:187: “entre le moment où il est et le moment
où il est achevé dans l’être, ‘par-fait’, il s’écoule un intervalle durant lequel il se meut vers
sa propre perfection, il agit; et par ses opérations, par les acquisitions qu’elles lui
obtiennent, il développe les virtualités qui sont en lui, dans la forme par laquelle il est ce
qu’il est et est ouvert à devenir parfait dans la ligne de ce qu’il est déjà”).
115
Pinckaers, Sources of Christian Ethics, 409. We are not far from the insight of Henri
de Lubac, when he argues, “Nature obeys its ontological ordination by desire, just as the
free will must obey the moral law by love” (“La nature obéit à son ordination ontologique
par le désir, comme la volonté libre devra obéir à la loi morale par l'amour”) (Henri de
Lubac, Surnaturel: Études historiques [Paris: Aubier, 1946], 490).
116
Pinckaers, Sources of Christian Ethics, 229.

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Marie-Dominique Chenu explains of the perspective of St.
Thomas—by which “the end of human nature, beatitude and
perfection” are all simultaneously realized.117 Most especially in
the pursuit of the good that befits, or corresponds to, his nature,
man cooperates with the Creator in the ongoing work of his
creation: the perfecting of his nature and his person. After all,
“when we love a thing, by desiring it, we apprehend it as
belonging to our well-being,” St. Thomas says.118 In the final
analysis, therefore, an act is moral not simply because it is natural,
but because it accords with the intrinsic requirements, or
demands, of personal perfection, which can only be determined
and realized as specific to human nature. Hence, the moral
quality of an act might be judged according as it leads, or
contributes, to both the good of humanity and the good of the
acting person, who is perfected, or fulfilled, within fruitful and
loving communion.
From this perspective, the natural inclination to selfpreservation should be understood, Pinckaers explains, as
“progressive” rather than “conservative”: as integral to the
dynamism of natural perfection.119 Such, of course, is also the
case of the properly human inclination to marriage. It is “because
of the interior demand of love”—a demand that “penetrate[s] to
the heart of our free will,” so as to touch upon the very meaning
of our persons—“that marriage tends toward physical and
spiritual fruitfulness in generation and education.” Such is the
“law of giving, written at the heart of every love,”120 the “law of
generosity inscribed on the soul as well as the body of every man
and woman.”121 For if love “does not know how to give, if it is
not fruitful,” it “will sooner or later die.”122 That is why “to
117
Marie-Dominique Chenu, Introduction à l’étude de Saint Thomas d’Aquin, 3d ed.
(Paris and Montreal: Vrin, 1974), 267: “Les actes humains (et par eux tout le cosmos
qu’ils organisent et exploitent) sont comme les ‘pas’ par lesquels se réalise, sur la voie du
retour, la fin de la nature humaine, béatitude et perfection à la fois.”
118
STh I-II, q. 28, a. 1.
119
Pinckaers, Sources of Christian Ethics, 425.
120
Ibid., 441.
121
Ibid., 446.
122
Ibid., 441.

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infringe upon this law is,” Pinckaers teaches, “to compromise the
very life of love in its truth and depth.”123
We are not far from what Karol Wojtyła refers to as “the law
of the gift . . . inscribed deep within the dynamic structure of the
person”: the law according to which “one becomes most fully
oneself” when “one becomes a gift for others.”124 Far from
implying that man is thereby constrained by his own body and its
sex, this law points to the very “freedom of the gift” that is
expressed in and through the body, in accord with its (the body’s)
“spousal” meaning or attribute: “the power to express love,” and
not just any love, but “that love in which the human person
becomes a gift and—through this gift—fulfills the very meaning
of his being and existence.”125 Hence, as Pinckaers concludes,
“we are free not in spite of our sexuality but because of it, since
through sexuality the inclination toward the other, which
provides the human and moral dimension of sexuality, is
exercised in a special way.”126
Far from disregarding their natural inclinations and the natural (and thus also the sacramental) “language” of their proper
bodies,127 spouses are thus said to “interpret”128 them as guides,
or norms, pointing the way to properly moral action: action that
contributes to authentic human perfection. In the words of John
Paul II:
The person, by the light of reason and the support of virtue, discovers in the
body the anticipatory signs, the expression and the promise of the gift of self,
in conformity with the wise plan of the Creator. It is in the light of the dignity
of the human person—a dignity which must be affirmed for its own sake—that
reason grasps the specific moral value of certain goods towards which the
person is naturally inclined. And since the human person cannot be reduced to
a freedom which is self-designing, but entails a particular spiritual and bodily
123

Ibid., 446.
Karol Wojtyla, “The Personal Structure of Self-Determination” in idem, Person and
Community: Selected Essays, trans. Theresa Sandok, O.S.M. (New York: Peter Lang,
1993), 194. Reference here is made to Gaudium et Spes, 24.
125
Pope John Paul II, Man and Woman He Created Them, 185-86. See also idem, “A
Meditation on Givenness,” trans. Maria MacKinnon, Communio 41 (2014): 871-83.
126
Pinckaers, Sources of Christian Ethics, 442.
127
See Pope John Paul II, Man and Woman He Created Them, 531-47.
128
International Theological Commission, “In Search of a Universal Ethic,” 63.
124

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MICHELE M. SCHUMACHER

structure, the primordial moral requirement of loving and respecting the person
as an end and never as a mere means also implies, by its very nature, respect for
certain fundamental goods, without which one would fall into relativism and
arbitrariness.129

Because in fact human persons are capable of discovering the
objective meaning of the human body, they are also capable of
subjectively appropriating it by way of ethical acts that respect
and foster that meaning. Within the context of the conjugal act,
they are not merely passive recipients of a message inscribed
within their bodies, therefore, but actors who freely engage in
this concrete act with knowledge of its significance. Such, indeed, is the condition of their free, and thus human, engagement. That is why Pinckaers presents true love as “tyrannical”: as
unwilling to accept “half measures”130 and as consequently
willing to accept both the “privations that correct the excesses
and the deficiencies to which the passions lead,” and “the effort
of submitting oneself to a discipline.”131
Such are the demands of chastity, which Pinckaers presents as
integrating sexuality within the human person “by reason’s
interior mastery” in service of love.132 The natural desire to have
children is one that “impose[s]” itself on us, Pinckaers notes. So
too does the desire for goodness and truth, whence the question
“to know which will dominate, what will direct us: our desires,
our passions, or reason that presents to us the good and the
true.”133 It nonetheless bears repeating that although the
perfection of the moral act entails that the passions be governed
by reason, it also entails that man be moved to the good not only
by his will, but also by his sensitive appetites. We should not be
surprised, then, that St. Thomas follows Aristotle in teaching that
reason governs “not by a despotic supremacy,” over the passions,
“which is that of a master over his slave;” but rather “by a politic

129

John Paul II, Veritatis Splendor, 48.
Pinckaers, Passions and Virtue, 16.
131
Ibid., 15; cf. CCC 1766-2340.
132
Pinckaers, Sources of Christian Ethics, 439; cf. CCC 2339, 3242, 2346, 2395.
133
Pinckaers, Passions and Virtue, 33.

130

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463

and royal supremacy, whereby the free are governed.”134 Hence,
for example, the man who has the “habit of chastity” is said by
the angelic doctor to form moral judgments “by a kind of
connaturality.”135 As for Pinckaers, far from opposing one
inclination (the sexual impulse in view of procreation, in the case
at hand) to another (the spiritual desire to seek truth and
goodness), he suggests that reason allows us to perceive their
unity within the good of marital love that is both (inseparably)
procreative and unitive and to adapt our behavior (by the exercise
of responsible parenthood through marital chastity) in view of
preserving this unity.
CONCLUSION: THE UNITY OF HUMAN ACTIONS
WITHIN THE CREATIVE WORK OF DIVINE PROVIDENCE
The point in all of this of course is that “the inseparable
connection established by God between the unitive significance
and the procreative significance which are both inherent to the
marriage act”—to return to the formulation of Humanae Vitae
12—points to the perfect unity of divine creation and divine
providence, which has foreseen that we should act as cooperating
causes in the great good of procreation. In fact, St. Thomas
ventures beyond the Aristotelian affirmation that a thing must
first be perfect before it can become a cause of others to argue
that in so doing it resembles God, who is the universal cause of
all being: “Therefore, since a created thing tends to the divine
likeness in many ways, this one whereby it seeks the divine
likeness by being the cause of others takes the ultimate place.
Hence [as] Dionysius says . . . ‘of all things, it is more divine to
become a co-worker with God’; in accord with the statement of
the Apostle: ‘we are God’s coadjutors’ (1 Cor. 3:9).”136

134

STh I-II, q. 17, a. 7.
STh II-II, q. 45, a. 2.
136
ScG III, c. 21. Similarly, Pincakers argues that human beings are made in the image
of the Creator, “because they are called by their actions to imitate God in some way, even
in his creative activity” (“Les êtres spirituels sont ainsi faits à l’image de leur créateur parce
qu’ils sont appelés par leurs actes à imiter Dieu en quelque façon, dans son activité
135

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MICHELE M. SCHUMACHER

Of course, this is not to deny that with regard to all other
living beings of a biological nature, “an ontological threshold is
crossed” in the generation of a human being, whose soul is
directly created by God. The properly human activities of
knowing and willing, precisely as immaterial, “do not contain, in
their internal structure, an organic activity,” as Georges Cottier
explains. That is why we cannot attribute to the father and
mother, who transmit human life “through organic functions,”
the being of a child possessing these spiritual faculties.137 In the
words of St. Thomas,
it belongs to man to beget offspring, on the part of the naturally corruptible
body. But on the part of the soul, which is incorruptible, it is fitting that the
multitude of individuals should be the direct purpose of nature, or rather the
Author of nature, Who alone is the Creator of the human soul.138

Because, on the other hand, human generation really does terminate in a child whose soul is created immediately by God,
Cottier joins Paul VI in affirming that human parents “collaborate” with the Creator—by way, the Swiss philosopher adds,
of a sort of “synergy” between their own action and that of the
Creator.139
This, arguably, is the highest point of the mystery of
naturalism and personalism as it is played out in the dynamic
unity of nature and reason—or what Pope Benedict identifies as
the “harmony of objective and subjective reason”—within their
créatrice même”) (Pinckaers, “Appendice I: Notes explicatives,” in Thomas d’Aquin,
Somme théologique, I-II, qu. 6-17: Les actes humains, 1:326).
137
Georges Cottier, Défis éthiques (Saint Maurice, Switzerland: Editions SaintAugustin, 1996), 185: “avec l’être humain un seuil ontologique est franchi, par rapport à
l’ordre entier des vivants biologiques. L’âme humaine est directement créée par Dieu. . .
. Les activités proprement humaines, dans ce qui les distingue des activités des autres
animaux, n’impliquent pas, à titre intrinsèque, un organe matériel, comme la vue requiert
l’œil. Les activités de l'intelligence et de la volonté sont en elles-mêmes des activités
spirituelles qui ne comportent pas, dans leur structure interne, une activité organique.
Elles sont immatérielles. C’est pourquoi la production dans l’être d’un sujet possédant ces
facultés spirituelles ne peut être attribuée au père et à la mère qui transmettent la vie par
une activité qui s’exerce grâce à des fonctions organiques.” Cf. Comp. Theol. 1.93.
138
STh I, q. 98, a. 1.
139
See Cottier, Défis éthiques, 186: “synergie.” Cf. Paul VI, Humanae Vitae, 1.

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common source, namely the “creative reason of God.”140 As such,
it is also realized within the dynamic unity of human action
within divine causality. Because God has created human nature
with intellect and will, he has set man free willingly to
cooperate—or to refuse to cooperate—with God’s own work of
creating and perfecting human life. “For we are his
workmanship, created in Christ Jesus for good works, which God
prepared beforehand, that we should walk in them” (Eph 2:10).
Ultimately, in fact, Pinckaers shows us that naturalism and
personalism are united in the providential action of God, who
calls upon human persons to participate in the work of their own
perfection: a perfection that reaches a certain (natural and thus
also spiritual) excellence in their free and responsible
collaboration with the Creator in the transmission of human life.
In this way Pinckaers’s theology responds to what Joseph
Ratzinger recognized in 1989 as “one of the most pressing tasks
of theology today,” namely, a renewed emphasis upon creation
in view of once again “discern[ing] a spiritual message in the
material world.”
We have to make evident once more what is meant by the world’s having been
created “in wisdom”. . . . Only then can conscience and norm enter again into
proper relationship. For then it will become clear that conscience [which he
elsewhere defines as “reason that is open to the language of being”141] is a “consciens,” a “knowing along with” creation and, through creation, with God the
Creator. . . . And then it will be apparent how harmony with creation, whose
wisdom becomes our norm, does not mean a limitation upon our freedom but
is rather an expression of our reason and our dignity.142

140
Pope Benedict XVI, “The Listening Heart: Reflections on the Foundations of Law,”
Visit to Bundestag, Berlin, September 22, 2011: http://www.vatican.va/
content/benedict-xvi/en/speeches/2011/september/documents/hf_ben-xvi_spe_20110922
_reichstag-berlin.html.
141
Ibid.
142
Joseph Ratzinger, “Difficulties Confronting the Faith in Europe Today” (A Meeting
of the Congregation for the Doctrine of the Faith with the Presidents of the European
Doctrinal Commissions in Vienna, 2-5 May, 1989), Communio 38 (2011): 728-37, at
732-34.

The Thomist 84 (2020): 467-80

SANCTIFIED THOUGHT AND AFFECTION IN AQUINAS’S
TEACHING ON NATURE AND GRACE
ROMANUS CESSARIO, O.P.
Ave Maria University
Ave Maria, Florida

T

HE WORK OF Fr. Servais-Théodore Pinckaers occupies a
signal place within the Thomist commentatorial tradition.1
Consider, for instance, one well-known feature of Fr.
Pinckaers’s work, namely, his signature 1960 article that
reminded the theological world that virtue is not a habit, at least
in the modern sense of the term. This essay finds its pedigree
within the Thomist commentatorial tradition.2 Vernon J. Bourke

1
An earlier version of this article was delivered as the concluding keynote address at
“Virtue Applied: The Theology of Virtue and Contemporary Questions,” a conference in
honor of Servais-Théodore Pinckaers (1925-2008), University of Fribourg, Switzerland,
Oct. 27, 2018, organized by Fr. Michael Sherwin and supported by the Swiss National
Science Foundation.
The Pinckaers-Sherwin scientific relationship is a remarkable example of the Thomist
commentatorial tradition at work in the twenty-first century. On the existence and worth
of this tradition, see Romanus Cessario, O.P., and Cajetan Cuddy, O.P., Thomas and the
Thomists: The Achievement of Thomas Aquinas and His Interpreters (Minneapolis:
Fortress Press, 2017).
2
S.-Th. Pinckaers, “La vertu est tout autre chose qu’une habitude,” Nouvelle revue
theologique 82 (1960): 387-403; English version, “Virtue Is Not a Habit,” Cross Currents
12 (1962): 65-81. Pinckaers observes that virtue ensures a constant disposition in the self
for choosing the good ends of human perfection. The psychological modification in the
capacities of the soul (potentiae animae) accounts for the promptness and facility of action
which the virtuous person displays in the performance of the good deed. The creative
powers of the virtuous person are actually heightened by the development of virtue rather
than restricted. On the other hand, vice crimps the soul. There are a thousand ways to do
good creatively, but only one way to act viciously, even if it takes a variety of forms.
Pinckaers later developed this insight in his Sources of Christian Ethics. See also my The

467

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ROMANUS CESSARIO, O.P.

(d. 1998), a North American Thomist, illustrates a proximate link
in the chain of interpreters who correctly taught about Aquinas’s
use of habitus. Bourke’s 1938 doctoral dissertation from the
University of Toronto, Habitus as a Perfectant of Potency in the
Philosophy of St. Thomas Aquinas, just underwent a new printing
in 2017.3 One of course may cite other ligaments to the commentatorial tradition, especially from among French–speaking
Thomists.4
Father Pinckaers’s highly regarded disdain for moral casuistry
led him to eschew the discussion and adjudication of individual
moral cases. On one of the few occasions that I heard him speak
about a particular moral problem, I frankly found myself taken
aback. A young Dominican at the Albertinum required an exam
in order to obtain his faculties for hearing confessions. Father
Pinckaers and I were among the assigned examiners. The question of what moral obligation governs one’s paying government
taxes arose. As an American with an eye on the assiduousness of
the Internal Revenue Service, I was in the process of pointing out
the grave moral responsibility that obliges one to respect tax
assessments. Legal justice, I insisted, requires payment down to
the last penny. Father Pinckaers interrupted my instruction to the
candidate with this presumably Gift-of-the-Holy-Spirit correction. “No, you don’t have to pay every Franc demanded,” he
told the young priest; “Everyone knows governments overcharge!” I thought to myself, could this view ever qualify as a
Probabiliorist opinion about tax paying? In any case, I recall this
personal experience with Father Pinckaers to explain why I begin
this communication with a very concrete moral case, one that has
bedeviled Catholic moral theologians and priest confessors for a
long time.

Moral Virtues and Theological Ethics (2d ed.; Notre Dame and London: University of
Notre Dame Press, 2008), esp. chap. 2.
3
Andesite Press, 2017.
4
For a bibliography of Fr. Pinckaers’s work and information on his intellectual
formation, see S. Pinckaers, O.P., The Pinckaers Reader, ed. J. Berkman and C. S. Titus
(Washington, D.C.: The Catholic University of America Press, 2005).

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I. SANCTIFIED AFFECTION
Catholic teaching on masturbation affords one of the few
instances in the Catechism of the Catholic Church (CCC) where
remnants of post-Tridentine casuistry appear explicitly. CCC
2252 includes a list of factors that may attenuate the masturbator’s moral culpability. At the same time, the text upholds the
harm that autoeroticism brings to a person. One eminent
twentieth-century Christian theologian explains this delicate
matter in the following words.
For me the real evil of masturbation would be that it takes an appetite which,
in lawful use, leads the individual out of himself to complete (and correct) his
own personality in that of another (and finally in children and grandchildren)
and turns it back; sends the man into the prison of himself, there to keep a
harem of imaginary brides. This harem, once admitted, works against his ever
getting out and really uniting with a real woman. For the harem is always
accessible, always subservient, calls for no sacrifices or adjustments, and can be
endowed with erotic and psychological attractions which no woman can rival.
Finally, among these fantasies the man is always adored, always the perfect
lover; no demand is made on his unselfishness, no mortification ever imposed
on his vanity. In the end, they become merely the medium through which he
increasingly adores himself.5

These words come from the pen of the English novelist and
Christian apologist Clive Staples Lewis (1898-1963). In this brief
excerpt from a letter sent in 1956 to a certain Keith Masson,
Lewis draws attention to the place that the sense passions of the
soul hold in the Christian life.
Because the topic of the passiones animae requires
considerable explanation for a contemporary audience, I follow
the practice of Eric D’Arcy who, in a simplified manner,
translates the phrase as “emotions.”6 Of course, the complexity

5

C. S. Lewis as cited in L. W. Dorsett, Seeking the Secret Place: The Spiritual Formation
of C. S. Lewis (Grand Rapids, Mich.: Brazos Press, 2004), 123-24.
6
E. D’Arcy, The Emotions, vol. 19 of Summa theologiae, Blackfriars edition (New
York: McGraw-Hill Book Company, 1967), xxi-xxvi.

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ROMANUS CESSARIO, O.P.

of Aquinas’s psychological theory remains.7 On the other hand,
English speakers, at least, will recognize the general subject area
under discussion when one speaks of “passions.”
To speak about sanctified thought and affection in Aquinas’s
teaching on nature and grace requires first of all a remark on the
place that the impulse (concupiscible) and contending (irascible)
emotions hold in the theological life—or, better, the theologal
life, an expression that appears twice in the English translation of
the Catechism of the Catholic Church.8 The expression
“theologal life” means in short the uplifted life of grace, virtues,
gifts, and beatitudes. It would make no sense to speak about an
uplifted life unless a foundation for the structure existed. In other
words, the “theologal life” describes how divine grace perfects
human nature.
In his Passions and Virtue, recently translated into English, Fr.
Pinckaers observes that the humanization of the emotions did not
receive significant attention from modern moral theologians,
especially of the casuist stripe. “In the world of casuistry,” he
writes, “the question of the passions is reduced to a determination of the sinful character of the antecedent or consequent
passion to the will.”9 Confessors, for instance, when a person
confessed having experienced movements of either the contending or the impulse emotions, were accustomed to ask this
question of a penitent: “Did you give your consent to them?”
Most often, in fact, this question arose within the context of the
penitent’s confessing lustful or unchaste thoughts. It would have
been easy to conclude that Christian living required of a tempted
person a firm use of will power in order to hold at bay
threatening and unruly emotions. One may easily take away from
such counsel the image of a divided soul.

7
For a brief explanation in English, see J. P. Reid, O.P., Fear and Anger, vol. 21 of
Summa theologiae, Blackfriars edition (New York: McGraw-Hill Book Company, 1965),
139-83.
8
CCC 2607 and 2803.
9
S. Pinckaers, O.P., Passions and Virtue, trans. B. M. Guevin (Washington, D.C.: The
Catholic University of America Press, 2015), 5.

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471

Even today, secular critics complain that the Church
demonizes emotions. If the publication of Humanae Vitae in July
1968 marks a symbolic point of rupture in the theretofore
accepted practice of moral theologians, we may say that casuistry
has been out of favor for about half a century. At the same time,
postconciliar moralists have not spent much time explaining
virtuous emotions. Those theorists, for example, who still
exercise themselves with versions of what Veritatis Splendor calls
teleogisms discuss human emotions mainly as grounds for
rationalizing immoral activity.10 To take Lewis’s abovementioned
example, moralists who discount the moral harm of masturbation
sometimes justify their laxism by appeal to the emotional
instability of adolescents and those others given over to the
solitary vice.11 Lewis’s explanation of the harm that autoeroticism
causes to the Christian soul made to love God and neighbor
should give such theorists moment for pause. Only a sophist
would attempt to gainsay the concision, limpidity, and cogency
of Lewis’s thought, which finds an echo in the Magisterium's
insistence that masturbation fails to achieve the “mutual selfgiving” that God made venereal pleasure to accompany.12 At the
same time, Lewis leaves unanswered the kind of question that
many an adolescent would likely pose to his or her spiritual
director or confessor, namely, “What am I to do when lustful
urges, which manifest themselves in the bodily members, seem to
overcome me?” Few spiritual guides of this period, I would dare
to estimate, hold out the promise that human emotions can gain
a rectified stability within the theologal life. Otherwise put, they
fail to instruct on how grace can shape nature’s affection.

10

See Veritatis Splendor 73 and 74.
Efforts to minimize the culpability that attaches to an immoral act should be
evaluated in light of Veritatis Splendor 63: “It is possible that the evil done as a result of
invincible ignorance or a non-culpable error of judgment may not be imputable to the
agent, but even in this case it does not cease to be an evil, a disorder in relation to the
truth about the good.”
12
For example, see CCC 2352.
11

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ROMANUS CESSARIO, O.P.

II. SANCTIFIED THOUGHT
Let me make an important clarification. The four centuries of
casuist dominance did not leave the Church without some
instruction on living the Christian life. We know that the casuist
period in moral theology, which ran roughly from the midsixteenth century to the mid-twentieth, also witnessed the production of some of the masterpieces of Western Christian
spirituality. Francis de Sales’s Introduction à la vie dévote (1609),
Louis de Montfort’s Traité de la vraie dévotion à la Sainte Vierge
(1712), and the several spiritual treatises composed throughout
the eighteenth century by Alphonsus Liguori (d. 1787) provided
spiritual consolation to Catholics worldwide. These Catholic
instructions, to be sure, helped people cope with disordered emotional commotion in their lives. One may argue, in fact, that these
spiritual authors aided Catholics in discovering the formative
influence of divine grace on the human person. A pronounced
emphasis on the power of grace to transform the believer appears
especially in the thoughtful works of De Montfort, who counsels
his readers to let themselves be formed in Mary’s womb so as to
grow into the image of her Son.13 By and large, however, the
great spiritual authors of the post-Tridentine period developed
their treatises in conjunction with the ethos of casuistry. Francis
de Sales’s rejection of the Thomist thesis on infused moral virtue
in favor of a charity-based approach to Christian living sets the
tone for the modern period, for charity of course resides in the
will, the rational appetite.14 All in all, the modern spiritual
authors remained skittish about the possibility of a person’s
developing virtuous emotions, that is, sanctified affections.
Consider one example: Saint Alphonsus liked to attend Neapolitan operas, but he would remove his glasses so as to avoid
visual contact with the luxurious stage settings and, one assumes,

13

See R. Cessario, “Mary in the Dominican Tradition,” Nova et vetera (Eng. ed.) 1
(2003): 27-42.
14
For further information, see Cessario, Moral Virtues and Theological Ethics, 104,
esp. n. 24.

SANCTIFIED AFFECTION AND THOUGHT

473

the bosomy prima donnas. This somewhat mechanical application of pastoral theology would make for a hard sell today.
The period of Thomism that flourished under the inspiration
of Pope Leo XIII prompted some important theological reflection
on the positive role that human emotions can hold in the moral
life. Pinckaers himself cites the early twentieth-century authors
H. D. Noble, O.P., and M. Corvez, O.P. In 1908, the former
published a two-part article, “La nature de l’émotion selon les
modernes et selon saint Thomas.”15 He concludes that the
moderns differ from Aquinas. Corvez, for his part, between 1949
and 1952 edited the three volumes of the La revue des jeunes
edition of the Somme théologique that deal with “Les passions de
l’âme” (STh I-II, qq. 22-48). One may opine, however, that these
pioneer restorers of Catholic teaching on humanized emotions
made little headway in overcoming the view that, by the
twentieth century, had become a commonplace, namely, that one
best understands human emotions as physiological expressions of
a material nature. The opioid crisis in North America and the
#MeToo movement in the United States supply the most obvious
and recent evidence to suggest that we require a more
sophisticated account of human emotions than that proposed by
materialist theorists who reject the immateriality of the human
soul. Can one seriously envisage the cosmic dance of the eternal
masculine and feminine choreographed satisfactorily by
government-enforced protocols such as requiring consent forms
before sexual engagement, attending anger management sessions,
and the like?
Jacques Maritain, in his Three Reformers, anticipated our
present circumstances and located their remote causes within the
arc of modern philosophy.
The rationalist self had wanted to be self-sufficient. It refused to lose itself in
the abyss of God, where it would have found itself, and now it can only seek
itself in the abyss of sensitive nature, where it will nevermore find itself. Love,
which was the panting of the spirit, and which presupposes as a condition of
15
H. D. Noble, O.P., “La nature de l’émotion selon les modernes et selon saint
Thomas,” Revue des sciences philosophiques et théologiques 2 (1908): 225-45 and 466-83.

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ROMANUS CESSARIO, O.P.

self-surrender the self and its immanent life, has gone. Nothing but egoism
remains and there is no ego, but only a stream of phantoms. Rousseau’s man is
Descartes’s angel acting like a beast.16

Is it too overreaching to suppose that Maritain drew upon elements of basic Thomist teaching on the workings of infused
moral virtue as exercises of both sanctified thought and sanctified
affection?
For many reasons, including the fragility of theories that pit
rational will against sense emotion, attentive scholars deem the
Thomist teaching on the humanization of man’s emotions one of
the most important lessons for contemporary Catholic moral
theology. To return to the Thomist commentatorial tradition,
allow me to stress the importance of recognizing a continuous—
that is, without identifying discrete periods—commentatorial
tradition that follows the work of Aquinas. The Thomist
commentatorial tradition perpetuates a sapiential approach to
theology. When its authors treat human emotions within the
theologal life, they stand united in upholding the pre-ethical
anthropology of the imago Dei. They—that is, the noneclectic
commentators—also rely on the Aristotelian account of the
human soul and its powers.17
Among the several benefits that derive from their adhering
faithfully to the commentators, Thomists recognize that the
virtue of prudence enables them to give an account of how reason
can, in fact, shape the emotional life of an individual. Veritatis
Splendor points to this teaching when it insists that
knowledge of God’s law in general is certainly necessary, but it is not sufficient:
what is essential is a sort of “connaturality” between man and the true good.
Such a connaturality is rooted in and develops through the virtuous attitudes of
the individual himself: prudence and the other cardinal virtues.18

16
J. Maritain, Three Reformers: Luther, Descartes, Rousseau (New York: Thomas Y.
Crowell Company, 1929), 100.
17
For further information, see J. A. Weisheipl, s.v. “Thomism,” New Catholic
Encyclopedia (New York: McGraw-Hill, 1967), 14:126.
18
Veritatis Splendor 64.

SANCTIFIED AFFECTION AND THOUGHT

475

Bona fide Thomist authors from the sixteenth century on offer
the best commentary on this important feature of Church
teaching that does not assume a divided soul as its default
position. Instead, Thomists assert that sanctified thought and
affection create a harmonious interplay of the soul’s rational
powers and human emotions.
III. THE THEORY
In 1974, Marie-Dominique Chenu published an article titled
“Les passions vertueuses: L’anthropologie de saint Thomas.”19
He opens the article by recalling briefly the condemnations of
Aquinas by ecclesiastics of an Augustinian stripe that occurred
within a few years of his death. Aquinas’s canonization in 1323
effectively nullified these critiques, which otherwise would have
undermined one of Aquinas’s central moral teachings, namely,
that the sensitive powers of the soul, the capacities for emotional
reactions, supply apt “seats” for virtuous formation. “Saint
Thomas held,” writes Chenu, “that, contrary to his Augustinian
contemporaries, the impulse and contending passions [emotions]
present, even down to their physiological engagement, proper
subjects for virtuous formation.”20 Chenu observes that Aquinas
did not flinch from drawing the consequences that his “radical
opinion” about the constitution of the human being—namely,
that “the intellectual principle is united to the body as its form”—
entailed.21
Chenu identifies the principal places where Aquinas develops
his teaching on the formation of a virtuous emotional life. One
should single out the Quaestio disputata De virtutibus in
communi and the Quaestio disputata De virtutibus cardinalibus.
In these texts and others, Aquinas and, following him, Thomists
never cede to the emotional life of man a control that the rational

19

M.-D. Chenu, “Les passions vertueuses: L’anthropologie de saint Thomas,” Revue
philosophique de Louvain 72 (1974): 11-18.
20
Ibid., 12.
21
STh I, q. 76, a. 1. See also CCC 365.

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ROMANUS CESSARIO, O.P.

powers of the soul cannot engage. Even in the face of strong
arousal of emotion, accompanied by what Aquinas calls a corporis
transmutatio—a physical eruption of sorts—the human person
retains the capacity to integrate these emotions and to shape them
in conformity with virtuous habitus. Aquinas’s doctrine of the
unity of the human soul, with powers really distinct from the
essence of the soul, undergirds his confidence about the
development of rectified sense appetite. “One thing has one being
as a substance,” he writes, “but there can be many activities. And
so there is one soul but many powers.”22 Sense powers, as the
name potentia suggests, are capacities that can be developed by
way of a passive reaction. To develop this thought, Aquinas describes the sense powers of the soul as being “in a midway
condition.” He further explains: “For the bodily change [corporis
transmutatio] conjoined to their acts shows that they use a bodily
organ, but that they are in some way lifted above matter is shown
by this, that they are moved on command and obey reason.”23 Of
course, Aquinas holds clearly that the “principal act of virtue is
choice.”24 Still, he equally insists that “by the habit of virtue, the
ultimate fulfillment of goodness is conferred on the act of virtue,
such that the irascible and concupiscible [contending and
impulse] follow the command of reason without difficulty.”25
One should not pass over lightly the qualification that Aquinas
introduces when he signals what makes moral virtue a requirement for Christian perfection—that is, “the ultimate fulfillment
of goodness,” to borrow his own phrase. To put it differently, the
Common Doctor holds that the sensitive powers of the soul—the
contending and the impulse emotions—when virtuously formed
or shaped confer this “ultimate fulfillment of goodness” on the
virtuous act. Why, one inquires? Virtuous emotions embrace the

22

See STh I, q. 77, a. 2, ad 3.
De Virtut. in Comm., a. 4, ad 4. Translations of De virtutibus in communi and De
virtutibus cardinalibus are taken from Thomas Aquinas, Disputed Questions on Virtue,
trans. R. McInerny (South Bend, Ind.: St. Augustine’s Press, 1999).
24
De Virtut. in Comm., a. 4, arg. 2.
25
De Virtut. in Comm., a. 4, ad 2.
23

SANCTIFIED AFFECTION AND THOUGHT

477

truth about the good of the human person “without difficulty.”26
Recall that habitus formation renders the action that flows from
this metaphysical perfectant of the soul prompt, joyful, and
easy.27 How strange this conviction must sound to those who
regard the discipline of Christian living as an intolerable burden,
if not an unwarranted imposition on the human being’s natural
movements.
Aquinas entertains no such uncertainty. Instead, he employs
the familiar analogy of the slave and the free man. Reason
governs the emotional powers of man not by a royal or despotic
rule but by a political rule. This political rule allows Aquinas to
claim reasonably that the emotions remain true seats of virtue.28
Though he admits that the rebellion of the sense appetites against
reason cannot be wholly removed by human virtue, at the same
time he acknowledges that divine power can remove all such
rebellion. In a startling phrase, he alerts us to the extraordinary
power of divine grace. He says that the removal of all rebellion
to right reason on the part of the sense appetites can be effected
“by the divine power which is even capable of changing
natures.”29 He surely absorbed the full meaning of the biblical
text that reports Jesus as saying, “Come to me, all you who labor
and are burdened, and I will give you rest. . . . For my yoke is
easy, and my burden light” (Matt 11:28, 30). Many texts from
Saint Paul also come to mind.
The Thomist teaching on the power of divine grace and the
dynamics of the infused virtues seems especially useful in our
present circumstances. A recent Gallup poll (June 5, 2018) offers
this alarming statistic about the number of Americans who deem
the use of pornography morally acceptable: “One of the biggest
spikes was among men ages 18-49. Already a majority last year
(2017) at 53 percent, the number soared 14 percentage points to

26

Ibid.
For further information, see Bourke, Habitus as a Perfectant of Potency in the
Philosophy of St. Thomas Aquinas.
28
See De Virtut. in Comm., a. 4, ad 8.
29
De Virtut. in Comm., a. 4, ad 7.
27

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ROMANUS CESSARIO, O.P.

67 percent this year (2018).”30 One should note that the majority
of candidates for both marriage and the priesthood come from
Catholic men within this age group.
The “ultimate fulfillment of goodness” survives physical
death. Aquinas dares even to assert that though the separated soul
enjoys only its rational powers, there remains in heaven
something of the virtues of temperance and fortitude. Why? The
virtues of personal discipline can never escape their “derivation.”
What does he mean? Aquinas answers in article 4 of his disputed
question on the cardinal virtues, which asks, “Whether all the
cardinal virtues remain in heaven.”31 One objector observes that
the sense parts of the soul do not exist in the separated soul.
Aquinas, however, remains resolute about the permanence of
virtuous formation:
The object of the act is the object of the power; hence such powers are
connected; and thus after death they do not remain in the actually separated
soul, save virtually, as in a root because the powers of the soul flow from its
essence. But these virtues are in the irascible as far as their derivation
[derivationem] goes, but according to origin and beginning they are in reason
and will because choice is the principal act of moral virtue and it is an act of
rational appetite. But by a kind of application this choice terminates in the
passions of the irascible and concupiscible because of temperance and
fortitude.32

This explanation, Chenu observes, reveals the surpassing dignity
that Aquinas gives to the emotional life of man.33 The virtues that
shape man’s emotions shine even in heaven. While Aquinas
maintains that the virtues of temperance and fortitude remain in
heaven, their virtuous acts no longer serve an end to be attained
but an end already obtained. Chenu concludes by acknowledging,

30
Mark Pattison, “Americans’ Acceptance of Porn Hits New High This Decade,”
Catholic News Service, June 7, 2018 (https://cruxnow.com/church-in-the-usa/2018/06/
americans-acceptance-of-porn-hits-new-high-this-decade/)
31
De Virtut. Card., a. 4.
32
Ibid., ad 13 (English translation by R. McInerny [South Bend, Ind.: St. Augustine’s
Press, 1999], 140).
33
Chenu, “Les passions,” 15.

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479

sadly, that Aquinas’s finely tuned “morale des passions” did not
enjoy success among the bulk of Catholic theologians. Instead,
the Augustinian model of virtue, which placed the virtues only in
the higher powers of the soul, continued to influence mainline
Catholic thought. One may reasonably suppose that C. S. Lewis
would have been obliged only to encourage continence on
someone who may have been moved intellectually by his analysis
of solitary masturbation but was not sufficiently mature emotionally to avoid the practice.
To conclude, let me point out some contemporary research on
the humanization of the passions. About a decade ago, Fribourgtrained Paul Gondreau published an article entitled “The Passions
and the Moral Life: Appreciating the Originality of Aquinas,”
which captures the salient features of Aquinas’s teaching on the
human emotions within the theologal life.34 Earlier, Gondreau’s
doctoral thesis was published in Europe under the title of The
Passions of Christ’s Soul in the Theology of St. Thomas Aquinas.35
Two American editions followed.36 This major work on the rectification of human emotions exposes an oftentimes neglected
feature of Aquinas’s virtue theory. Gondreau reminds us of the
thoroughgoing Christological inspiration that stands behind
Aquinas’s insistence about the rectification of the sense passions
of the soul. When Aquinas affirms that divine power can change
the nature of things, he surely thinks above all of the substantial
holiness of Christ’s human nature. So the Common Doctor easily
can proclaim, “Christus perfectissime habuit omnes virtutes.”37
Aquinas’s teaching on human emotions within the theologal life
offers, in the measure available to human persons, the same hope
of transformation to believers, the members of Christ’s body.
Given the largely unsuccessful remedies for emotional upset
proffered by the human and medical sciences, what Aquinas
34

The Thomist 71 (2007): 419-50.
Beitrage zur Geschichte der Philosophie und Theologie des Mittelalters (Münster,
Achendorff, 2002).
36
Scranton, Penn.: University of Scranton Press, 2009; reprint, Providence, R.I.:
Cluny Media, 2018.
37
STh III, q. 15, a. 2; see also ibid., ad 2.
35

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ROMANUS CESSARIO, O.P.

teaches about rectified emotion should form part of all moral
instruction given within the Church of Christ, especially in
Roman Catholic seminaries. I cite Gondreau’s work inasmuch as
it offers one example of a certain theological wisdom that, I
contend, finds a special home in Fribourg. As one indebted to the
Dominicans of the Albertinum and to my own alma mater, the
University of Fribourg, allow me to express the hope that this
sapiential style of theology—“Theology at Fribourg”—will
remain strong and alive, so as to bear much fruit.38

38
For discussion of an earlier period, see R. Cessario, O.P., “Theology at Fribourg,”
The Thomist 51 (1987): 325-66.

BOOK REVIEWS
Children of God in the World: An Introduction to Theological Anthropology. By
PAUL O’CALLAGHAN. Washington, D.C.: The Catholic University of
America Press, 2016. Pp. vii + 595. $39.95 (paper). ISBN: 978-0-81322900-3.
English-language graduate courses in theological anthropology have been in
want of a good textbook for years. Rondet’s has long been out of print;
Journet’s and Hardon’s, while excellent in themselves, contain neither the detail
nor the depth that a graduate course requires; and other significant
contributions to the subject area have tended toward addressing one or more
particular areas of controversy (e.g., the relationship between nature and grace,
or the complementarity of man and woman) rather than theological anthropology as a whole. The prospect of filling this void is daunting for any author.
As O’Callaghan notes in this book (18), the treatise on theological anthropology
may be a relatively recent phenomenon in the history of theology, built on the
backs of a collection of Scholastic treatises, but in its brief lifespan it has been
asked to address such wide-ranging topics as biblical criticism, gender theory,
hermeneutics, and neuroscience. O’Callaghan’s textbook is thus as welcome as
it is ambitious, providing a complete overview of the treatise on theological
anthropology in its current form, doing justice to the myriad of interdisciplinary
fields with which it has come into contact in the last half century, and offering
the studious reader a series of generous bibliographies in its notes that touch on
nearly every topic of importance or controversy that it addresses.
Part 1 (“Methodological Considerations”: chaps. 1-3) situates O’Callaghan’s
approach to theological anthropology within the wider fields of social anthropology, philosophy, and theology. From the start, we see the breadth of
O’Callaghan’s erudition, as he places the book’s subject on a map of contemporary thought that stretches from Scholastic theology to the history of religions
to important works of literature from any number of periods, languages, and
cultures. Within this broad field, O’Callaghan orients himself by dividing the
scientific question of “what” human nature is (18-20) from the philosophical
and theological question of “who” human persons are (21-25, 33). O’Callaghan
argues that, by focusing on the concrete situation of the human species,
reflection on human nature fails to account for the transcendent aspirations of
human persons towards immortality (16); by studying what is determined and
481

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universal in human nature, it fails to account adequately for the uniqueness and
liberty of human persons (22-24); by focusing on knowledge outside the context
of love, it risks turning knowledge into a means of domination (27). A
phenomenological approach to the experience of human persons overcomes
these limitations, but even then, unaided reason encounters certain “binomials”
of human experience that appear mysteriously irreconcilable (26): the
relationships between concreteness and transcendence, universality and
uniqueness, determination and freedom, and knowledge and love (24-25, 3133). In this context, the person of Jesus Christ “reveals man to himself”
(Gaudium et Spes 22, quoted on 64), not only in the sense of revealing the
healing of human nature by grace and its elevation to glory, but even revealing
the very intelligibility of human nature as such: only “Christ, the incarnate
Logos, is the one who gives a unitary and harmonic intelligibility . . . to human
nature” (80-81).
Part 2 (“The Historical Development of the Doctrine of Grace”: chaps. 411) begins with a nuanced meditation on the imago Dei in Scripture (chap. 4).
Honing in on the patristic distinction between image and likeness, while ably
placing it in the context of contemporary biblical scholarship (93-95),
O’Callaghan sees in the term imago two important aspects of human existence:
the human person is filial (in relation to God) and social (in relation to other
human persons) (96). While the imago Dei is present equally in all human
persons (98-99), Part 4 (“Christian Anthropology”: chaps. 18-25), which
addresses a range of disputed questions about the imago Dei, suggests that it
cannot be reduced merely to the level of nature or to the higher powers of the
soul, as Augustine’s psychological analogy of the Trinity would have it (419);
there is “an important” but not exclusive expression of it in “the union between
[male and female]” (533), as well as the other forms of human sociality that
radiate out from family life (498-89). The rest of part 2 unpacks O’Callaghan’s
discussion of the imago Dei with a comprehensive survey of the ways in which
the theological tradition has articulated its transformation by grace into the
likeness of God: in Pauline literature as incorporation into Christ (chap. 5), in
Johannine literature as eternal life (chap. 6), in the Eastern Fathers as
divinization (chap. 7), in Augustine as the reception of the Holy Spirit (chap.
8), in the medievals as created grace (chap. 9), in Luther and certain early
Reformers as faith (chap. 10), in the Council of Trent through the sacraments
(also chap. 10), and in the early modern and modern periods through the
various positions taken in the De auxiliis controversy, the heterodox
Augustinianisms of Baius and Jansen, and the proto-ressourcement of Petavius
and Scheeben (chap. 11).
O’Callaghan describes part 3 (“The Christian Theology of Grace”: chaps.
12-17) as “the central part of this treatise” (10). Like part 2, it begins with an
extended meditation on Scripture, this time on Rom 8:29-30: “For those whom
he foreknew he also predestined. . . . And those whom he predestined he also
called; and those whom he called he also justified; and those whom he justified

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483

he also glorified” (RSV; 215). Developing Barth, he interprets foreknowledge
and predestination as the election of the Church (217-24). Drawing on the
writings of Josemaría Escrivá, he creatively interprets calling as the vocation of
the persons in the Church to holiness and apostolate (224-35). Synthesizing
these two lines of interpretation, he treats justification as the person’s free
response to the offer of grace that is present in his personal vocation (235-38).
Finally, following Pannenberg, he views glorification as the eschatological
participation in eternal life that grace begins now and perfects hereafter (23842). Within this context, chapter 13 offers the reader a sublime and unparalleled
reflection on the role of the Holy Spirit as uncreated grace, drawing each one
of us up through the Church in response to our personal vocation into a loving
communion with the Trinitarian persons. Subsequent chapters address the other
fundamental aspects of the theology of grace: created grace (chap. 14), the
infused virtues and the gifts of the Holy Spirit (chap. 15), justification and merit
(chap. 16), and the need for grace (chap. 17).
One hesitates to critique such an otherwise excellent book. But while
O’Callaghan’s focus on person over nature places him comfortably within the
field of Thomistic personalism represented by John Paul II, the adversarial
manner in which O’Callaghan often frames the distinction is somewhat unnecessary to his aims. It may simply be the echo of rhetorical effect from the
classroom lectures on which the book is based, but the reader does wonder at
certain points whether O’Callaghan has done sufficient justice to the difference
between the Stoic understanding of nature and the Thomistic understanding of
nature. Certainly, we can agree that the Stoic understanding of nature entails a
comprehensiveness and control that are subject to the pitfalls that O’Callaghan
describes. Nonetheless, the Thomistic understanding of nature carefully
preserves the integrity and intelligibility of nature alongside its openness to
grace: in a variation on the oft-repeated Thomistic axiom, we might say that
grace not only perfects nature but also presupposes it. Thomas was aware of the
potential objection that the integrity of nature could seem to make the will’s
motion necessary. But he carefully avoided it by distinguishing between
necessary and free modalities in natural motion. By nature, all human persons
necessarily desire happiness, as Augustine had long ago observed at the
beginning of the Confessions. But only by free choice, as Augustine explores
throughout the same work and as Thomas repeats, does a given human person
pursue his happiness in some particular object.
O’Callaghan’s adversarial framing of the person/nature distinction also
affects his discussion of created grace. Explaining the character of Trinitarian
indwelling, O’Callaghan identifies in Thomas a shift from an “assimilative”
understanding of indwelling (at the level of nature) to a “relational” one (at the
level of the person) (284-85). However, O’Callaghan passes over the fact that
the key word in the texts of Thomas dealing with the so-called “assimilative”
understanding of indwelling, similitudo, is the Latin word for “likeness” in
Genesis 1:26. This is not to suggest that one should let the pendulum swing the

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other way and replace the relational with the assimilative understanding of
indwelling. It is merely to observe that the two go hand in hand: the human
person enters personal communion with the Trinitarian persons precisely
insofar as he becomes a “partaker of the divine nature” (2 Pet 1:4).
One is tempted to overlook the distinction between the divinization of the
person and the divinization of nature in the person as an exercise in
obscurantism, but it has important ramifications for Thomas’s understanding of
the relationship between sin and grace. On O’Callaghan’s reading, “Aquinas . .
. teaches that the theological understanding of sin and evil is not constitutive of
the treatise of grace” (180). There is a sense in which this could be true if it
were phrased relatively. In the mid-twentieth century, Lottin showed that
Aquinas backed away from the more extreme “Augustinianism” of the Lombardian school, for which the essence of original sin is that we are personally
culpable (albeit venially) for the presence of concupiscence in our nature. With
Anselm, Aquinas saw the essence of original sin as nature’s loss of grace, limiting
personal sin to that which implicates the will. How, then, do individual human
persons share in the sin of Adam? Here, Thomas does not abandon Peter
Lombard’s Augustinianism altogether. He distinguishes between peccatum
naturae (a sin committed by human nature itself), the spoiling of original justice,
which causes culpa naturae (guilt of nature) in all persons who supposit human
nature, and peccatum personale (personal sin), which causes culpa personalis
(personal guilt) in all persons who commit it. The grace of justification thus
entails a twofold cleansing and elevation: it heals individual human persons
from personal sin and raises them to a personal relationship with the Trinitarian
persons, as O’Callaghan lucidly describes, but it only does so insofar as it heals
and elevates human nature in those persons to a participation in the life of God.
Since human nature is shared among all human persons, the cleansing and
raising of nature in the person thus forms the ontological basis of the relational
character of our redemption—a point which de Lubac first brought to the fore
in Catholicisme.
These difficulties notwithstanding, O’Callaghan deserves high praise for
filling an important gap in theological scholarship. Not only does his work, as
intended, provide the contemporary classroom with a textbook that has been
needed for decades, but the breadth and depth of his erudition will additionally
earn this book an important place as a reference text for scholars, as well as
deserved recognition as a constructive contribution to theological anthropology
in its own right.
JACOB W. WOOD
Franciscan University of Steubenville
Steubenville, Ohio

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Thomism and Predestination: Principles and Disputations. Edited by STEVEN A.
LONG, ROGER W. NUTT, and THOMAS JOSEPH WHITE, O.P. Ave Maria,
Fla.: Sapientia Press, 2016. Pp. 336. $39.95 (paper). ISBN: 978-1-93258979-5.
This collection of thirteen essays, with an introduction by Steven A. Long,
examines the principles of the Thomist theology of predestination and the
disputes that have arisen about it among Aquinas’s disciples. While the promotion of the book might lead one to suppose that the volume delivers a
coherent and complete defense of the classical Thomist account, the limitations
arising from the fact that it is the product of papers given at a conference mean
that the collection is not entirely that. Nevertheless, it deserves a warm
welcome, because the issues connected with predestination that are debated
among Catholic theologians have never been solved to general satisfaction, and
the loss of interest in Thomism during the twentieth century hindered
theological progress in them.
Two essays (chaps. 1 and 4) offer a general orientation around the central
questions, although Thomas Joseph White, O.P.’s “Catholic Predestination”
would have been more usefully placed first overall. White prescribes a retrieval
of a balanced medieval Augustinianism, in contrast to the Calvinist and Barthian
versions of the modern period, with Calvin’s elision of divine causation and
permission, the irresistibility of grace and its restriction to the elect, and Barth’s
subordination of Calvinism to what effectively amounts (claims White) to
universal salvation in Christ. For a Catholic theology of predestination that
avoids these extremes, he offers six principles from Aquinas: (a) that everything
morally good in a human being comes from God’s creative power and
providential assistance; (b) that moral “evil stems from a . . . free, . . . culpable,
and naturally defective” human act (103); (c) the primacy of divine grace over
free human cooperation; (d) the offer of “the possibility of salvation to all
human persons,” where “the mystery of perdition originates from the free
defective resistance to or refusal of . . . grace” (109); (e) God’s eternal
foreknowledge of all the saved, where “his divine will for their salvation is the
effective cause of their predestination to divine glory” (114); and (f) God’s
innocence of moral evil, where “reprobation occurs in light of the antecedent
permissive decree of God, which is in no way causal of sin” (116).
What, however, is the status of the classical Thomism that White favors?
Does it genuinely represent Aquinas, and is it sound? In the first and most
significant chapter, Serge-Thomas Bonino, O.P., places the current state of the
question on predestination in the context of the shift among Thomists away
from the classical interpretation found in Réginald Garrigou-Lagrange, O.P.
Bonino goes through the different factors that have contributed to a general
rereading of Aquinas: scriptural and patristic renewal, the “demonization” of
Aquinas’s commentators (36), and the tendency to find diverging lines of
thought in his corpus. Bonino concludes against several theologians that it

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cannot be inferred from scriptural teaching on communal and “economic”
predestination that the traditional question of individual predestination to
eternal life is a false problem. As for Aquinas’s appropriation of the Fathers,
which has recently enjoyed enthusiastic appreciation, Bonino notes that,
paradoxically, its progress brought Aquinas’s mature doctrine in the Summa
theologiae closer to the very Augustinian position on predestination with which
theologians now feel uncomfortable. While many believe that the later Thomist
tradition dealt in debates foreign to Aquinas and introduced concepts like
“physical premotion” that distort our understanding of him, Bonino confirms
the presence within Aquinas’s mature thought of the classic positions articulated
by such commentators as Domingo Báñez, O.P., and Garrigou-Lagrange.
In contrast, the revisionist approaches are found wanting because they
sacrifice some element of Aquinas’s teaching, striving to retain grace’s primacy
and divine knowledge of sin without God’s sovereign causality through physical
premotion and his antecedent permissive decree of sin. If they do not reject
physical premotion outright, they limit its scope. For Bonino, such attempts fail
through their substitution of the eternal presence of creatures to God for divine
causality as the medium of divine knowledge, such that God knows creatures
because they exist rather than, as Aquinas holds, that creatures exist because
God knows them. Jacques Maritain’s “breakable motion” (44), moreover, not
only fails to retain an adequate understanding of God’s knowledge of sin, but
also undermines grace’s primacy by conceding the last word in salvation to the
creature. Bonino recommends that theologians sacrifice none of the relevant
data, whether metaphysical or revealed: while Thomists may not be able to
demonstrate the ultimate “conciliation” of all these truths, recognizing the
limits of their science, they can hold in obscurity that such conciliation is
possible and show that it is not impossible.
Not all the remaining chapters follow Bonino’s recommendation in detail.
Lawrence Feingold (chap. 7) takes the view that the modern primacy of the
division of actual grace into efficacious and sufficient, found in the
commentators, introduced a false dilemma into theology. Feingold opts instead
for Aquinas’s division into operative and cooperative grace as primary and,
rejecting the classical Thomist causal account of divine knowledge, appears to
risk having God’s eternal knowledge determined by the presence to him of
creatures, the very thing Bonino seeks to avoid. Despite a nod to Bonino,
Matthew Lamb’s account of Bernard Lonergan, S.J., on the intelligibility of
predestination (chap. 9) is more of a piece with Feingold: adherence to
Lonergan goes hand in hand with the dismissal of Báñez as a reliable interpreter
of Aquinas on divine motion. Michael Waldstein’s essay (chap. 11), though its
argument is hung on the hook of presenting Balthasar as a Thomist critic of
Barth’s predestinarian theology, stands out as more of a continuation of a
distinct debate on pure nature with Long (see the latter’s introduction on 1 and
14-19).

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Despite the volume’s diversity, most chapters more or less directly favor the
agenda set by White and Bonino. Some frame the questions in interesting ways
that escape a narrow approach of concentrating solely on traditional points of
contention. Michael Dauphinais (chap. 5) highlights the crucial role of God’s
goodness by exploring Aquinas’s Commentary on Ephesians, which makes clear
that, in the Common Doctor’s words, “God’s predestining will has no other
ratio than the communicating of the divine goodness to his sons” (128). In
chapter 3, “From Eternal Sonship to Adoptive Filiation,” Roger W. Nutt shows
how Aquinas’s treatment of Christ’s own predestination adds clarity to our
understanding of how the eternal reality of predestination in fact unfolds in this
temporal order. No presentation of Aquinas on predestination can be complete
without attention to the content of the Summa’s Christological Tertia pars.
That said, the really controversial points are rooted back in the Prima pars.
On this score, Long’s essay on the role of divine causality in predestination
(chap. 2) provides a very thorough defense of the classical position. Though
Aquinas never used the phrase “physical premotion,” Long makes the case that
the doctrine is nevertheless present in his works and defends in its connection
the fundamental importance of divine simplicity, where God is Pure Act and in
no way dependent on creatures. He criticizes Maritain (whose theory he
previously accepted) for holding that a creature will receive an unbreakable
motion for a free act if it first does not negate a breakable motion, since that
negation of a negation involves a paralogism and must reduce to a positive
effect; Francisco Marín-Sola, O.P., for conceding to a creature in receipt of a
lesser grace the excessive power to apply that grace to a greater effect, and for
proposing that grace may be “fallibly efficacious,” which Long claims is contrary
to divine simplicity (65); and Lonergan for a weak presentation of both divine
and creaturely motion that is inadequate to Aquinas’s texts. The most pellucid
treatment of physical premotion, however, is from Joseph G. Trabbic (chap. 6),
who elegantly refutes Brian Shanley, O.P.’s claim that the classical doctrine
lowers the transcendent God to the level of a secondary cause. According to
Trabbic, physical premotion does not compromise but rather requires divine
transcendence.
What is said in favor of classical Thomism is not limited to defenses of
Aquinas’s metaphysical theology. In an interesting contribution (chap. 12),
Christopher M. Cullen, S.J., shows how St. Ignatius Loyola in his Spiritual
Exercises adhered to the Thomist position on physical premotion and so on,
prior to the rise of alternative theories among the Jesuits. From the Dominican
tradition of spirituality, Romanus Cessario, O.P., adds (chap. 10) the classical
position on the grace of predestination in the Marian devotion of the priesttertiary Louis-Marie Grignion de Montfort—a happy addition to the volume.
However, while these contributions, like those of Dauphinais and Nutt,
round out the case in favor of classical Thomism, what is crucially missing from
this volume is a study of the texts of Báñez himself and so of the relationship of

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his teaching to that of Aquinas. This is surely what is required to verify the
credentials of such doctrines as physical premotion.
One of the more difficult aspects of this teaching is how our sinning escapes
such motion. Thomas M. Osborne, Jr., sets out (chap. 8) the positions taken by
some of Aquinas’s early modern interpreters on how to hold both that God
causes sin’s act and that he does not cause sin itself or its deformity. On this
issue, Thomists have disagreed over whether the material aspect of sin is subject
to premotion. Osborne’s assessment shows how individual Thomists, by
drawing not only on Aquinas himself but on commentators who preceded them,
clarified the issues in the light of Scotist claims about sin as privation (Cajetan),
Protestant teaching that God is the cause of sin (Cano and Soto), and the
Molinist doctrine that God does not cause sin’s material aspect (Báñez, Alvarez,
and Lemos). With its discussion of key distinctions, such as natural and moral
causality and natural and moral contrariety, this chapter I found to be the most
informative and enjoyable. It shows the fascinating creativity of Aquinas’s
commentators but underlines how serious is the lack of the inclusion of a study
of Báñez’s wider teaching on premotion and grace.
Perhaps more difficult still than the role of physical premotion in sin is God’s
decree permissive of sin. Negative reprobation, the other side of the coin to
predestination in Aquinas’s account, includes not only punishment by reason of
sins freely committed, but God’s permission of sins in the first place. In the
shadow of Jean-Hervé Nicolas, O.P.’s refusal from the 1980s to continue his
previous, thoroughgoing defense of this decree, Bonino insists that it remains
the default solution and cannot be jettisoned on the basis of God’s universal
salvific will and divine innocence. Bonino argues that it follows securely from
“several inescapable doctrinal constraints” (40), including the sovereignty of
divine causality in the metaphysical order, the primacy of grace, and God’s
knowledge of sins. He does not think that one can infer a priori the permission
of sin (and negative reprobation) as a means to the end of manifesting God’s
justice, even though sins, once committed, do become an opportunity for such
manifestation (47-48). Rather, Bonino holds that reflection on the reasons for
sin’s permission can only be a posteriori, once reprobation is presupposed.
While Garrigou-Lagrange had taken from Aquinas the explanation that the
reprobation of some serves the predestination of others, Bonino and Long, like
Nicolas, emphasize creaturely fallibility, such that God allows some creatures
to be what they are, that is, to act according to their natures and to fail.
In the final chapter, Barry David, interpreting Aquinas’s treatment of
predestination in the genre of Christian confessio, suggests it would better elicit
thanksgiving among its readers if Aquinas’s opinion on minority predestination
were amended in terms of majority predestination, with universal
predestination reckoned possible (which is how he characterizes Barth). Barry
raises here the question of the difficulty of interpreting the contents of
Scripture. To me, this suggests that without a fresh and full verification of a
basis in Scripture for the various elements of the Thomist account of

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predestination—a verification not really undertaken in this volume—that
theology cannot hope to persuade.
SIMON FRANCIS GAINE, O.P.
Pontifical University of St. Thomas Aquinas
Rome, Italy

The Cleansing of the Heart: The Sacraments as Instrumental Causes in the
Thomistic Tradition. By REGINALD M. LYNCH, O.P. Washington, D.C.:
The Catholic University of America Press, 2017. Pp. xii + 225. $65.00
(cloth). ISBN: 978-0-8132-2944-7.
As this volume’s title suggests, Reginald Lynch offers insight into how the
sacraments pertain to the very “essence and purpose of the Church’s life” (2).
The book has four, complementary chapters.
Chapter 1, “Historical Considerations,” begins by situating the subject of the
book, Aquinas’s teaching on sacramental causality, in relation to the influence
of St. Augustine, the school of St. Victor, Peter Lombard, and the later medieval
schools. Lynch points out a number of distinctions made by Augustine in his
works against the Donatists that had lasting significance for sacramental
theology. Lynch argues that “perhaps most importantly, Augustine drew a clear
distinction between a sacrament and its fruit: while Baptism itself cannot be
repeated, the fruition or grace of the sacrament can be lost and subsequently
regained” (11). This important contribution became the catalyst for many
further Scholastic developments. “Hugh of St. Victor . . . began a final synthesis
of Augustinian sacramental doctrine that would become normative for many
scholastic authors” (14). Hugh’s synthesis includes the doctrine that the
sacraments contain grace as a medicine is contained in a container. Peter
Lombard, who had studied under Hugh, then offered an even more developed
account of sacramental causality. After a few pages about Aquinas, the chapter
moves through the positions of the subsequent schools, especially the teachings
of the Franciscans and Dominicans. The chapter also treats the reforms of Trent
and ends with a helpful section on “contemporary considerations,” which
discusses figures from the twentieth century—such as Casel, Leeming,
Schillebeeckx, Rahner, and Chauvet—and the teaching of the Second Vatican
Council. Lynch concludes his historical presentation by positioning the Thomist
perspective on sacramental causality against the other dominant perspectives:
“Unlike its medieval, modern, and contemporary alternatives, the Thomist
approach to sacramental causality offers an integration between cause and
effect, sign and sacred reality, that relates intrinsically to the human person in

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the order of grace . . . [and does so] with a degree of clarity and theological
precision that is not often found in contemporary sacramentology” (66). A
careful study of this chapter gives the reader an advanced understanding of how
the doctrine of sacramental causality developed from the Donatist controversies
through the twentieth century, and how major figures like Albert the Great,
Bonaventure, Aquinas, and Scotus sought to clarify the nature of sacramental
efficacy.
In the second chapter, Lynch considers Aquinas’s teaching on sacramental
causality in his Commentary on the Sentences. At the heart of the mechanics of
his early position lies the distinction between divine and creative modes of
efficient causality. As a result, the first section of this chapter provides a
treatment of Aquinas’s teaching on divine causality and creation. Creatio ex
nihilo differs from human artistic productivity on many important levels:
“While a creaturely artist uses tools to accomplish a work of art, God’s role as
first principle implies that the act of creative artistry must not only be ex nihilo
but also immediate. Because nothing preexistent can be involved in a properly
creative act, creation necessarily proceeds directly from the eternal will of God
who is the principal cause of all” (74-75). There is, however, another sense in
which God does work as an artist when he uses tools to influence “that which
he has already created” (78). This opens the way for types of instrumental
mediations, like the Incarnation and the sacraments, in which God acts upon
creation as the principal agent yet with the help of intermediaries. By mapping
Aquinas’s doctrine of divine causation in the first section of this chapter, Lynch
is able to pinpoint a critical question in relation to sacramental causality: if the
ultimate effect of the sacraments pertains to the supernatural order, in what
sense can created instruments be said to cause this effect? As Lynch details in
the second section of the chapter, by adverting to the doctrine of analogy,
Aquinas teaches that an instrumental efficient cause is perfective or dispositive
depending on whether its causation reaches its ultimate effect (perfective
causality) or merely disposes for the ultimate effect (dispositive causality).
Water can be used to clean something. Or it can be used to dispose, such as by
moistening soil to receive seed, in which case it does not produce the ultimate
effect of the soil’s reception of the seed. “In the Sentences, Aquinas uses this
distinction between perfective and dispositive efficient causality to describe the
instrumental causality of the sacraments. Aquinas teaches that the sacraments
‘reach’ (pertingere) a certain proximate effect that takes places in the soul, even
though their power as instruments does not reach the ultimate finality of the
action” (81). “Among Thomas’ contemporaries,” Lynch adds, “it was
commonplace to speak of grace as something created ex nihilo” (82). As a result,
“[Thomas’s teaching in the Sentences on] dispositive causality is an attempt to
preserve the principal agency of God with respect to grace” (83–84). The
chapter ends with a summary of the uses of the concept of the Greek word
“organum [instrument],” which Aquinas adopts in the Sentences but not with

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the penetration that is on display in his later expositions of sacramental
instrumentality.
The third chapter moves through Aquinas’s post-Sentences works, marking
developments in his thinking on sacramental causality. Lynch begins his
consideration with the disputed questions De veritate and De potentia Dei. He
notes that, despite what appears to be the same language in regard to causality,
there are a number of shifts in Aquinas’s thought on grace in both works. By
clarifying the nature of grace as a created accident in the soul, Aquinas is able
more fully to associate the instrumental action of the sacrament with its
causation. “While there are important parallels to be drawn between the act of
creation and the concreation of grace, the two are not entirely congruent. This
incomplete correspondence between creation and re-creation removes one of
the principal objections to the involvement of created instrumental causality in
the production of grace in the soul” (118). Lynch goes on to consider Aquinas’s
Summa contra Gentiles and Summa theologiae, in which the Angelic Doctor
further augments the developments of his De veritate and De potentia Dei. In
regard to the sacraments, Aquinas completely drops the language of
“dispositive” causality; rather, in the Summa theologiae, “Aquinas distinguishes
two kinds of causes: principal and instrumental, with no further division within
the category of instrument” (121). In the Summa theologiae, Aquinas also
clarifies the relationship between the sacraments’ nature, which is that of both
sign and cause. As Lynch explains, principal agents do not take on the character
of a sign in relation to their effects whereas instruments can be considered as a
sign in proximity to their effect: a knife can be both a cause and a sign of a cut.
“In this way [instruments] cannot be causes alone but are signs and causes
inasmuch as they are moved by the principal agent. . . . Sacraments are
instruments in the full sense because they are ordered to the holiness of another
(aliquid sacrum) as both signs and causes” (122-23). To explain, Lynch also
refers to a helpful exposition of Aquinas’s teaching by Cajetan that illumines the
development of the Angelic Doctor’s thinking. Cajetan refers to the music
produced by a harp when moved by a musician. A harp can make “noise” when
played by a “nonharpist,” but it makes music when moved by a real musician
(125). Likewise, the sacraments cannot touch the soul by their natural elements,
but, as instruments moved by God to confer grace, they do touch “the heart
because of the power of God” which is at work within them (126). Lynch
concludes the chapter with considerations of Domingo Báñez’s development of
Aquinas’s doctrine of instrumentality vis-à-vis the obediential potency of
creatures and of John of St. Thomas’s position on sacramental grace.
The final chapter examines Aquinas’s teaching on sacramental causality in
light of Melchior Cano’s theory of moral causality. Cano’s thought is of interest
not only for its influence on later sacramental theology but also for how he
formulated it in relation to Renaissance humanism. As Lynch points out, the
concerns of humanism affected Thomists in various ways. “Cajetan engaged the
humanist question in theology by reinvesting in biblical commentary and the

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study of ancient languages” (159). Other Thomists took more inspiration from
humanism than just that of higher standards of intellectual cultivation. “In
Vitoria, and then more clearly in Cano, we see a decision not only to be in
dialogue with humanism but to invest in humanist methodology itself” (ibid.).
The result of this decision was that the speculative and scientific commitments
of Aquinas’s legacy gave way to more practical and logical concerns. For
Aristotle, logical pursuits were ordered to metaphysical realism and precision.
However, for the Renaissance Thomists who followed humanists like Valla and
Agricola, the methodological shift made “persuasion and probability [count] for
more than rational certainty” (160). As a result, the use of dialectic by the
Scholastics to present and pursue truth gave way to rhetoric “that produces
conviction in its audience” (166). Cano’s work reflects these methodological
commitments, which caused him to break with the mainline Thomist tradition
on sacramental causality.
Lynch begins by helpfully mapping Cano’s reasoning on the question of
sacramental efficacy. Cano recognizes “two species of efficient causality:
‘natural’ causes and ‘moral’ causes” (171). The key distinction between the two
is that moral causes do not yield “contact with the effected end” (ibid.). Instead,
the moral cause works by inducing “another to action” (172). Coming close to
earlier sine qua non theories of sacramental causality, “Cano’s moral cause,” in
other words, “seems to imply some power of persuasion (if not efficient motion)
present in the cause itself” (175). Having sketched out Cano’s understanding,
Lynch then demonstrates that this approach cannot maintain the intrinsic
connection between the sacraments and grace required by Trent’s ex opere
operato doctrine. In particular, Lynch presents the response of Báñez to Cano’s
teaching. As Lynch summarizes him, Báñez, who sided with Cajetan’s reading
of Aquinas against Cano, points out that, “while Christ’s passion is certainly the
meritorious cause of our redemption, this assertion must be accompanied by a
discussion of the role of the sacramental elements themselves as physical
instruments in the conferral of grace” (183). Ultimately, what is at stake is the
ratio of the Incarnation itself. Christ’s death is not efficacious merely at the level
of persuasion but as the “physically efficacious” instrument by which salvation
is accomplished (185). It is from the physical efficacy of the Incarnation that
the sacraments derive their instrumental power as causes of grace. Lynch ends
this chapter by demonstrating how the issues at play in Cano’s teaching and the
Thomistic response have deep significance in understanding the de auxiliis
controversy and the trend toward nominalism in contemporary theology.
The importance of what Lynch has accomplished in this work cannot be
overemphasized. The scholarship is of the highest quality. Simply put, there is
no theological work within the last fifty years that treats this topic with as much
clarity as Lynch does in these pages. His engagement with Aquinas’s major
commentators, teasing out their key lines of insight and development, makes
this volume of value to all students and scholars of sacramental theology. Lynch
concludes the volume with the words, “Because of the importance of their

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effects, the efficacy of the sacraments will always be of central relevance and
should never be marginalized or forgotten in theological discourse” (205).
Indeed, there is scarcely a single theological topic bearing more directly on how
the faithful are to pursue Vatican II’s “universal call to holiness” than the causal
efficacy of the sacraments in the order of grace. The Cleansing of the Heart gives
the Church a remarkable resource—most certainly a standard-bearer for years
to come—in support of this lofty end.
ROGER W. NUTT
Ave Maria University
Ave Maria, Florida

Divine Causality and Human Free Choice: Domingo Báñez, Physical Premotion
and the Controversy “de auxiliis” Revisited. By R. J. MATAVA. Leiden:
Brill, 2016. Pp. xii + 365. $194.00 (hardback). ISBN: 978-90-0431030-8.
Divine Causality and Human Free Choice is an adventurous, if occasionally
unsteady, attempt to summarize the infamous controversy de auxiliis and to
offer a Thomist solution to the problems of divine causality and human
freedom. Matava characterizes his work as “an exercise in historically informed
philosophical theology” (8) that seeks to understand the “less-studied” side of
the controversy, namely, the development of the “classical Thomist” position
of Domingo Báñez, rather than the more commonly studied position of his great
rival, the Jesuit Luis de Molina. The first four chapters are historical. Matava
introduces readers to the controversy between Báñez and Molina, outlines
Báñez’s position on divine causality and human free choice, explains Báñez’s
critique of Molina, and explains Molina’s critique of Báñez. After a transitional
fifth chapter on Bernard Lonergan’s critique of Báñez and Molina, Matava
offers his own interpretation of Aquinas with a close reading of STh I, q. 45,
a. 3. In his historical treatment of the controversy, Matava treats all of the
classical loci, both medieval and modern: physical premotion, middle
knowledge, sufficient and efficacious grace, predestination, providence, free
choice, indifference, the composed and divided senses, de dicto and de re
modality, the “grounding objection,” and so forth. In his more systematic
proposal, Matava expands this already wide field to include technical questions
about the relation of creation in order to argue that God’s causality of human
free choices is best construed as one instance of the broader mystery of creation.
Matava’s work is a must-read for anyone interested in these issues, although
I suspect many will find points on which to disagree with him. Unlike most

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modern theologians who enter into the ready-made academic debate about
“compatibilism” and “libertarianism,” Matava quotes liberally from the texts of
Báñez and Molina. For this reason alone, Divine Causality and Human Free
Choice marks a great advance over most works on the subject. Although Matava
sometimes depends too much on William Lane Craig and Thomas Flint for his
understanding of Molina, his work is especially useful for reminding us of the
theological resurgence of these debates with Norbert del Prado and Reginald
Garrigou-Lagrange. After Matava notes Báñez’s “uncompromising commitment” to what he calls “classical Thomism,” one might expect Divine Causality
and Human Free Choice to be a spirited defense of the great Dominican
Scholastic, but Matava’s account is more neatly dialectical: “both Báñez and
Molina,” he argues, “are right in their critiques of each other and, consequently
. . . both of their own respective positions are deficient” (322). Both share
suppositions that rendered the controversy unavoidable and unsolvable at the
time. It comes as little surprise, then, that Matava interprets the controversy de
auxiliis as a key moment in the genealogy of modernity.
As a result, Divine Causality and Human Free Choice is marred by some
dubious historical claims. Matava presents Ockham as the leader of nominalists
and speaks of “classical Thomism” as representing the dominant theological
paradigm in early modern Scholastic Catholicism. In truth, few agreed with
Ockham, and Thomism was but one school among many during the sixteenth,
seventeenth, eighteenth, and nineteenth centuries. Nor was the Thomist
tradition unified. The “classical Thomism” of Báñez and Medina attacked the
humanistic Thomism of Cajetan, Vitoria, Las Casas, and Cano as readily as it
attacked Franciscans and Jesuits. One also hears echoes of the old Lutheran
historiography adopted by Catholic historians like Joseph Lortz and Erwin
Iserloh—and subsequently adopted by both existentialist and transcendental
Thomists—when Matava says that the Church lacked the theological resources
to deal decisively with the issues raised by the controversy. The implicit promise
is that modern theologians now possess the requisite sophistication to deal with
these issues once and for all. Matava’s interpretation of Aquinas purports to
offer an articulation of a unified relationship between nature and grace, an
eschatology that makes better sense of the canon of Scripture as a whole, and a
new spirituality that avoids both fatalism and Pelagianism (7)—all things,
presumably, that the previous tradition lacks.
Báñez’s chief role in this study is to criticize Molina, whose chief role
appears, unfortunately, to be to suffer the criticism of Báñez. On Matava’s
reading, Báñez is the father of the modern “grounding objection,” the argument
many modern philosophers believe fatal to Molina’s scientia media. On such a
reading, Molina’s characteristic scientia media fails to rise to the level of true
knowledge because it “requires there to be contingent states of affairs that
obtain prior to creation” (146-47). Depending as it does upon God’s knowledge
of how free creatures might respond to his grace, Molina’s argument
compromises God’s impassibility. One might expect to hear Molina’s response

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in the chapter on Molina’s criticism of Báñez, but the chapter largely serves to
defend Báñez from Molina’s attacks rather than to explain the Jesuit’s position.
As a result, it is a bit anticlimactic when Lonergan emerges to offer his wellknown, but perfunctory, criticism of Báñez for failing to understand Aquinas
on motion and thus making causation a tertium quid between God and the
creature. Báñez deserves better than that. Besides, Lonergan’s criticism seems to
be vitiated by the celebrated Dominican’s insistence that we read his argument
metaphysically, rather than physically, and so avoid being misled by the phrase
“physical premotion” (43).
Matava also assumes Molinism to be the single Jesuit tradition. This is largely
unconvincing. In 1613, Claudio Acquaviva, the father general of the Jesuits,
enjoined the Society’s theologians to follow Suárez and Bellarmine, not Molina.
Congruism became the official teaching of the Society two years later under the
new father general, Muzio Vitelleschi. Matava believes he can surmount these
historical difficulties, but, like most attempts to collapse congruism into
Molinism, he fails to distinguish God’s foreknowledge and vision at key points
in his argument. Molina’s entire point of departure, however, was to banish
Scotus’s signa rationis from discussions of God’s eternal decree in order to
rescue the Angelic Doctor from concessions to the Subtle Doctor made unwittingly by Dominicans and Jesuits alike. As almost every Jesuit after Suárez
was at pains to point out, too, the scientia media was part of God’s scientia
simplicis intelligentiae and so by definition ante decretum. It was in no way
dependent upon God’s scientia visionis, which is of course cum decreto. One
would wish that Matava had foregrounded these issues in order to clarify what
was—and what was not—at stake in this debate. Seventeenth- and eighteenthcentury theologians agreed that the things God foreknows ante decretum
according to his scientia simplicis intelligentiae were divided between the
scientia rerum naturalium (which is absolute necessaria) and the scientia rerum
liberarum creaturis futurarum sub hypothesi (which is contingens). The things
that God foresees cum decreto were divided between the scientia rerum
decretarum absolute (which God knows via his visio absolutorum) and the
scientia rerum decretarum sub hypothesi (which God knows via his visio
conditionalium). Of course, the things that God shall decree to exist, both those
decreed absolutely and those decreed contingent upon other things, are
included among all possibles by definition. Much of the confusion about the
scientia media in modern writers arises from the fact that the scientia
conditionalium liberorum creaturis falls under both the scientia rerum liberarum
creaturis futurarum sub hypothesi (which God foreknows via the scientia
simplicis intelligentiae) and the scientia rerum decretarum sub hypothesi (which
God foresees via the scientia visionis). The scientia rerum liberarum creaturis
futurarum sub hypothesi, however, includes the scientia conditionalium
liberorum by definition. The praescientia conditionalium liberorum is directa,
and the visio conditionalium liberorum is reflexa. No other difference is posited

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in God’s scientia, which, as Molina was keen to point out, is one. At no point
does it depend upon the creature’s response to his grace.
Once this (admittedly technical) point is acknowledged, many of Matava’s
readings of Molina appear forced. Take, for example, Matava’s reading of the
clause quod positis omnibus requisitis ad agendum in Molina’s famous definition
of free choice (105). At no point is it clear that Molina interprets free choice as
the zero-sum game that Matava insists it is. Matava attempts to bolster his
critique of Molina’s Augustinian and Scotistic conception by pointing to the
Jesuit’s remark that God and the creature are partial causes acting as a single
joint cause in the creature’s free response. To secure this reading, however,
Matava must downplay Molina’s insistence that, by partial causes, he means
that both God and the free creature are complete causes in their own orders
(108-9). As a result, what Matava criticizes as Molina’s position, he later
defends as Báñez’s (178). When faced with the teaching of the Council of Trent,
Matava can muster no better argument than that Báñez’s reading of the council
is “possible” (199)—all the while neglecting to admit the rather obvious fact
that Molina’s reading is clearly in harmony with the text of the council and its
intentions. Such a hermeneutic is, not unlike Báñez and Molina at their worst
moments, more polemical than historical.
While Matava’s investigation of the original sources is laudable, his work
unfortunately displays a too-common tendency among Catholic theologians:
resurrecting Baroque sources only to scapegoat them. Not enough credit is given
to the sources in their own right and in their own context. Be they fitted or
forced, Báñez and Molina appear to have been inserted into an already existing
narrative. Greater awareness of modern assumptions—and modern
prejudices—is called for in such a project, and fewer hints of the odium
theologicum it purports to overcome.
TRENT POMPLUN
University of Notre Dame
Notre Dame, Indiana

Deification in the Latin Patristic Tradition. Edited by JARED ORTIZ. Washington,
D.C.: The Catholic University of America Press, 2019. Pp. ix + 313.
$75.00 (cloth). ISBN: 978-0-8132-3142-6.
Is there is a true theology of deification in the Latin Christian tradition? The
question is a contested one. While research on theosis in the Eastern tradition

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flowered in the twentieth century, it has commonly been asserted, as Jared Ortiz
notes, “that the Latin Fathers did not seriously hold a teaching about
deification” (9) or that any such teaching would have been imported from the
East (8). In recent years, though, scholars have argued that genuine teaching on
deification can be found in the Western tradition. Most attention has been given
to medieval Latin or even to Reformed theology rather than to the Latin
Fathers, apart from Augustine. This interesting and wide-ranging volume takes
a large “first step along the way” to filling this gap (2), presenting significant
evidence “that many Latin authors do hold deification as an integral part of
their theological vision, have deeply engaged it, and have done so by drawing
on a common Christian tradition which they developed in unique ways” (4).
One reason it is commonly claimed that the West lacks a teaching on
deification involves terminology. The technical vocabulary of deification (words
with the root deif-) is quite rare among the Latin Fathers, even though they
often refer to the idea of humans being assimilated to God and sharing in the
divine life. Because of this, as Ortiz notes in the Introduction, John Scotus
Eriugena observed in the ninth century that “while the use of the term
deification is very rare in Latin books, we certainly find the meaning [intellectus]
in many of them” (2). Eriugena’s distinction raises the question of what the
meaning of deification actually is, especially in light of concerns raised in recent
decades by Gösta Hallonsten and others that a precise concept is being diluted
by too loose an application. Hallonsten, who appears as a critical background
interlocutor throughout this volume, argues that the theme and the true
doctrine of deification must be distinguished; the latter—employing technical
terms, a dynamic anthropology of image and likeness, a Platonic concept of
participation, and the energies/essence distinction—should be reserved for the
Eastern tradition (“Theosis in Recent Research: A Renewal of Interest and a
Need for Clarity,” in Partakers of the Divine Nature: The History and
Development of Deification in the Christian Tradition, ed. Michael J.
Christensen and Jeffrey A. Wittung [Madison and Teaneck, N.J.: Fairleigh
Dickinson University Press, 2007], 287). Daniel A. Keating has responded that
the picture is more complex; some of these elements are central to the teaching
of Latin Fathers, and some are not found in the early Greek Fathers themselves
(“Typologies of Deification,” International Journal of Systematic Theology 17
[2015]: 276.) The principle that “the intellectus” of a theology of deification
“can be present, even if the terms are not,” guides the essays here (3). The
authors offer persuasive evidence that these Latin theologians employ “key
elements of a theology of deification,” understanding “salvation as participation
in God and the communication of his divine life to us” (3-4).
Ortiz grounds the volume well with an opening chapter on deification in the
Latin liturgy, the primary locus of theological experience where “Latin
Christians of the patristic period were regularly being deified” (9). Deification,
Ortiz argues, is a “crowning theme” in early Latin liturgical prayers and
mystagogical texts (10). Deification takes place liturgically, making

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“worshippers into gods” (29), as the Christian is transformed and grows “in
union with and likeness to God”; it is made possible by the “magnificent
exchange” of the Incarnation, for Christ’s own “divinized humanity . . . is the
basis for our own divinization” (11-12). Subsequent chapters follow in
chronological order from the third to the seventh century. The possible breadth
of the intellectus of deification is demonstrated by their differences, though key
elements become clear: participation in divine life or attributes (sometimes only
eschatologically), assimilation to Christ, the formula of exchange, and divine
adoption. The essays are well edited and helpfully unified by concluding
sections that present the essential aspects of the theology of deification in each.
Thomas Heffernan proposes that the Passion of Perpetua and Felicity,
although it does not employ “technical philosophical language,” portrays the
martyr’s being deified by participation in the divine attributes, emphasizing
“transcendence, incorruptibility, the gift of healing, revivifying the dead, and
an intimate union with God reserved for the martyr alone” (30-31). Mark A.
Frisius makes the challenging claim that deification, although almost universally
thought to have no place in Tertullian’s thought, is in fact “integral to his
soteriology” (59). Tertullian’s rigorist ethics has as its end, he argues, an
imitation of Christ that is perfected eschatologically, made possible by Christ’s
role as “sequester,” purifying human flesh and uniting it to divinity. In the
eschaton, perfected human flesh becomes like the angels, incorruptible, and
“the individual human . . . receives the divine image and qualities” (74).
Benjamin Safranski argues that for Cyprian, deification has an ecclesial context,
begun by rebirth in baptism, so that “the Christian begins to be divine through
assimilation into Christ’s body, adoption as a coheir with Christ, and
sanctification as a temple of the Holy Spirit” (76). Our “deification by
imitation” of Christ in baptism is fulfilled especially by imitating the mercy of
God in almsgiving (91). James L. Papandrea offers an interesting chapter on
Novatian, arguing that the latter fits on “a trajectory . . . from Irenaeus to
Athanasius” that “has as its focal point the concept of the communicatio
idiomatum” (94) first clearly expressed by Novatian in “the language of loaning
and borrowing” (104). In Christ, “the human nature receives immortalitas and
the divine nature receives fragilitas” (107), and so “our humanity [can] receive
sanctification and immortality, culminating in resurrection and eternal life”
(110).
While the third-century sources often seem to focus on deification as the
communication of specific divine attributes such as incorruptibility, many
fourth-century Fathers offer a more developed notion. Janet Sidaway argues
that Hilary of Poitiers “had an unusual but rich theology of deification” that
“focuses on the way we can ‘become God’ in the sense of sharing in the perfect,
glorified humanity of the incarnate Son” (131). The exchange formula for
Hilary is anthropocentric, evidenced by his view of the Transfiguration as
“anthropophany” rather than theophany—in it, we see Christ’s glorified
humanity, prefiguring the glorification to come through brotherhood with him

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(124-25). Brian Dunkle, S.J., offers a fine chapter on Ambrose, demonstrating
that Ambrose’s teaching on deification is rhetorically shaped for different
audiences. For the more advanced, he tends to use “formulas of divine/human
exchange and 2 Peter 1:4” to “speak directly of God’s union with humanity
through Christ.” To mixed audiences, he more often employs “themes of divine
adoption and ‘image and likeness,’ which imply indirectly the union between
God and the baptized” (134), and uses the language of nature and grace to
convey the idea of deification to congregants who “want to know how baptism
changes them” (151); here Dunkle responds directly to Hallonsten’s charge that
such language conveys a static anthropology incompatible with the Greek view
of theosis (134). Dunkle suggests that Ambrose may have avoided the language
of deification due to its “pagan resonances” (139). A number of other authors
in this volume similarly suggest that the terminology of deification is avoided
within the context of heresy or idolatry. For instance, Vít Hušek argues that the
meaning of deification in Jerome’s thought “is based on adoptive sonship, which
enables us to become sons of God and to participate in divine life,” calling us
to moral excellence (154). Yet Jerome is “cautious and conservative on the topic
of deification” (166), avoiding all Greek and Latin technical terms (153) as well
as the Platonic concept of participation, always insisting that “our participation
in God is not a change of human nature” (160) but instead requires us to
exercise our freedom for moral excellence (167). Hušek proposes that Jerome’s
caution may have had anti-Origenist roots (168).
The fourth- and fifth-century Fathers discussed in the following three
chapters—Augustine, Peter Chrysologus, and Leo the Great—offer some of the
clearest examples of deification theology, especially in their references to the
“wonderful exchange.” Ron Haflidson notes the scholarship already done on
Augustine’s theology of deification (169-70). The reader should be aware that,
as Haflidson is building on this previous research, he focuses only upon
Augustine’s eschatology. For Augustine, the saints not only enter but “become”
God’s Sabbath rest because their “eternal praise of God is incited and sustained
by a deified knowledge of God’s goodness” (181), a knowledge that begins on
earth but is fulfilled in heaven by “the perfection of the knower” (188). David
Meconi, S.J., insightfully examines Peter Chrysologus’s theology of deification
in its historical context in wealthy, imperial Ravenna. Peter’s use of the
exchange formula in his preaching is strikingly expressed in mercantile terms,
giving his words “a remunerative tone” (193). He seeks to persuade Christians
to appropriate and live the divine life won for them as children of God,
appealing to those wondering “to which sovereign court they belong” to
“embrace God as our only Father, our only defender and provider” (201).
Daniel Keating demonstrates convincingly that Leo the Great expresses a
theology of deification “in a way comparable to others of his day, including
Augustine in the West and Cyril of Alexandria in the East,” especially in his use
of the language of participation in the divine nature (215) and in his “dynamic
anthropology, Christologically and pneumatologically grounded, that expresses

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both the realistic and ethical aspects of our deification” (226). Although using
no deification terminology, Leo “richly” applied the exchange formula
throughout his career, showing “his conviction that Christ became fully what
we are so that we might become what he is and might partake of the riches of
divine life and power” (229-30).
Chapters on Boethius and Benedict of Nursia with Gregory the Great
conclude the survey. Michael Wiitala argues that although Boethius never refers
to Christ in his Consolation of Philosophy, he “developed a distinctly NeoPlatonic notion of deification that is nonetheless compatible with the orthodox
Catholic Christianity he professed” (231). Wiitala speculates that the
Consolation’s message is that Lady Philosophy “can identify that happiness is
only attainable through deification, [but] she cannot on her own sufficiently
identify how to achieve deification” (232). Luke Dysinger, O.S.B., argues for
“an understated but real doctrine of divinization” in the Rule of Benedict and
Gregory’s biography of Benedict in the Dialogues (271). In the Rule, “the
divinizing light and divine voice of scripture” give the monk a “heart opened
wide by the practice of asceticism” to see Christ in others (271, 261). Gregory
locates his “theology of divinization . . . in his doctrine of contemplation”
illuminated by the divine light (264). Dysinger shows effectively why even
Gregory Palamas considered these saints to be “paradigms of theosis” (270-71).
Norman Russell’s concluding chapter on deification in the Greek and Latin
Fathers is the crown of this volume, an appendix of sorts to his magisterial The
Doctrine of Deification in the Greek Patristic Tradition (Oxford: Oxford
University Press, 2004). Russell offers a definition of deification—“the
appropriation of divine life through participation in the incarnate Word in
whom human nature has been divinized through its assumption by the Word, a
participation that is accomplished sacramentally with the necessary support of
the moral life”—judging that these elements are “well represented” in the Latin
Fathers discussed here (273-74). There is agreement between East and West
that “deification is Christologically based, ecclesiologically expressed, and
eschatologically oriented” (293), while “undeniably,” particular emphases also
exist, which Russell attributes to “differences in the reception of the Origenian
tradition” (291-92).
This well-researched collection of essays opens new avenues into a
fascinating and little-known dimension of Latin patristic theology. It provides a
worthy contribution to what will surely be an ongoing discussion of the content
and limits of the intellectus of deification.
DARIA SPEZZANO
Providence College
Providence, Rhode Island

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Aquinas among the Protestants. Edited by MANFRED SVENSSON and DAVID
VANDRUNEN. Oxford: Wiley Blackwell, 2018. Pp. xi + 314. $94.95
(hard), $39.95 (paper). ISBN: 978-1-119-26589-4 (hard), 978-1-11926594-8 (paper).
This collection of essays testifies to the revival of constructive engagement
with the thought of Thomas Aquinas among Protestant theologians in recent
years. Thomas has long been treated by Protestants as the theologian par
excellence of the Roman Catholic Church, and to Catholics it has often seemed
that Protestant theologians have treated him merely as a foil who made the truth
of Reformation theology stand out more clearly, rather than a theological
source who could be incorporated in a positive way. This collection goes some
way toward showing that Protestant theologians in the centuries following the
Reformation made constructive use of Thomas as well as showcasing
contemporary Protestant engagements with Thomas. The first seven essays,
gathered under the heading “The Protestant Reception of Aquinas,” reveal the
positive use of Thomas by Protestant thinkers in the five hundred years since
the start of the Reformation. The next seven essays, constituting a section
entitled “Constructive Engagement,” show how Protestant theologians might
continue to use Thomas as a resource for thinking about issues ranging from
faith’s relationship to reason to virtue and the moral life.
The first section covers a wide range of figures, including well-known
Reformation-era Thomas-sympathizers such as Peter Martyr Vermigli (14991562) and Girolamo Zanchi (1516-90), as well as early modern figures such as
Richard Hooker (ca. 1554-1600), the Anglican biblical scholar William
Whitaker (1547/8-95), and the Lutheran scholastic Johann Gerhard (15821637). Nineteenth- and twentieth-century Reformed thinkers such as Abraham
Kuyper (1837-1920), Herman Bavinck (1854-1921), and Herman Dooyeweerd
(1894-1977) are also treated, as are the contemporary German Lutherans
Wolfhart Pannenberg (1928-2014) and Eberhard Jüngel (b. 1934). The essays
tend to focus on particular aspects of each figure’s thought (e.g., Hooker on law
or Gerhard on analogy), so it is not always clear how broad the influence of
Thomas is in those figures. But taken together, the essays show that some
Reformation-era and early modern Protestants were happy to draw on Thomas
as a source, and were unafraid to modify his thought, sometimes in a distinctly
Protestant way, sometimes in answer to other exigences.
Some essays, such as David Sytsma’s on Whitaker, present hitherto littlenoted influences flowing from Thomas into Protestant authors. Particularly
surprising, at least for this reviewer, was how extensively an exegete like
Whitaker drew upon Thomas, citing not only the Summa theologiae but also
his Pauline commentaries. Some essays, such as Torrance Kirby’s on Hooker,
offer expositions of thinkers influenced by Thomas but make little reference to
the texts of Thomas himself, making it difficult to evaluate the nature of that
influence. For example, Kirby notes that Hooker understands God as “causa sui

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and therefore gubernator sui” (95), which strikes me as rather different from
Thomas’s notion of God as uncaused. Indeed, Kirby cites Hooker’s description
of the eternal law as the law “which God hath eternallie purposed himself in all
his works to observe” (96), which sounds more like later nominalist construals
of the absolute and ordained will of God than it does Thomas’s account of God
himself as law. Unfortunately, Kirby offers no textually based exposition of
Thomas to address the question of whether Hooker is in fact departing from
Thomas on this point, and readers are left to draw their own conclusion.
One of the essays in the first section, by John Bolt, while substantively
concerned with Thomas in the work of several early twentieth-century
Reformed thinkers, is framed autobiographically in terms of the author’s own
growing doubts about the negative depiction of Thomas in the writings of
authors such as Kuyper and Francis Schaeffer (1912-84) and his coming to
appreciate certain motifs of Thomas’s thought. Bolt’s essay thus serves not only
as an account of one strand of Reformed anti-Thomism but also shows how
someone within the Reformed tradition might come to reappraise Thomas. In
this way, it blurs somewhat the distinction between the retrieval of past
Protestant engagements with Thomas and contemporary engagements with
Thomas by Protestant theologians.
One gets the impression that as we move into the nineteenth and twentieth
centuries Thomas is less often positively appropriated and more often used to
represent a distinctively Roman Catholic perspective. This may have to do with
the development of more distinctly “Protestant” and “Catholic” intellectual
traditions over time, though in the case of thinkers such as Pannenberg and
Jüngel criticisms of Thomas may have more to do with their engagement with
modern thought than with confessional identity. One weakness of essays on
specific figures is that it can be difficult to spot larger trends, though editors
Manfred Svensson and David VanDrunen do attempt in their introduction to
give something of an overview, noting a movement from “critique and
appreciation” in the early modern period to “an era of ignorance” stretching
from the Enlightenment to the middle of the twentieth century (14). They also
note the variety of engagements with Thomas in the last seventy years, ranging
from Anglican Thomists like Eric Mascall (1905-93) to various sorts of
postliberalism, suggesting that there is no monolithic “protest” engagement
with Thomas.
The essays in the second half make use of Thomas in discussing topics that,
for the most part, reflect twentieth-century Thomist preoccupations: faith and
reason, the nature of theology, analogy, nature and grace, virtue and social
ethics. There is, unfortunately, no extended engagement with Thomas’s
Trinitarian, Christological, or sacramental theology, but this is hardly surprising
since modern Catholic theologians have, until fairly recently, tended to neglect
those areas of Thomas’s thought as well. All of these essays attempt to draw on
Thomas for constructive purposes. Some might have been a bit more careful
about appropriating some of the standard Catholic narratives concerning how

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Thomas differs from other medieval thinkers, particularly Scotus. And in one
case, we get what I judge to be a somewhat garbled account of Catholic debates
over “pure nature.” But the essays are all interesting and worth reading.
One of the best essays, by J. V. Fesko, takes up the traditionally controversial
topic of justification and shows that, historically speaking, Thomas’s notion of
“infused habit” is not as alien to the Reformed soteriology as is sometimes
thought, and argues that this concept has much to offer contemporary
Reformed theologians. Not all the essays, however, focus on ProtestantCatholic differences. Indeed, a number of the essays, such as Sebastian
Rehnman’s essay “Philosophy Explored” or Michael Allen’s “The Active and
Contemplative Life,” use Thomas to discuss their topic—and along the way give
solid accounts of Thomas’s views—but spend relatively little time on how the
position they develop conforms to or departs from classic Protestant approaches
to these questions. Thomas has been completely appropriated as a theological
source, taking his place alongside Paul and Augustine and Calvin and Luther. In
these cases, the Protestants Thomas is “among” are the authors themselves, and
one is left to figure out for oneself—or to ignore as not particularly interesting—
the question of how “protestant” or “catholic” the position developed is.
Though not every reader will find every essay equally useful—someone wellversed in Thomas might not need yet another exposition of Thomas on a
particular topic, and someone new to Thomas might find that some essays spend
too little time expositing Thomas—most readers will find many of them both
useful and interesting. Taken as a whole, this collection can be seen as a sign of
hope that Thomas’s theology might serve as a place of fruitful encounter
between Protestants and Catholics and not simply as a battlefield.
FREDERICK CHRISTIAN BAUERSCHMIDT
Loyola University Maryland
Baltimore, Maryland

The Aristotelian Tradition of Natural Kinds and Its Demise. By STEWART
UMPHREY. Washington, D.C.: The Catholic University of America Press,
2018. Pp. ix + 260. $75.00 (cloth). ISBN: 978-0-8132-3041-2.
There are “two great waves of natural-kinds realism,” according to
Umphrey: the more recent beginning in Mill and others in the nineteenth
century, whereas the original, premodern wave spanned Aristotle through the
medievals (1). This book is an erudite philosophical history of that original wave
and its demise, the latter beginning with Galileo and ending with Darwin.
Although a central current in the history of philosophy, the question about

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whether the species that we instinctively pick out of the natural world are really
there or something we concoct and then project has never before received a
book-length study. This should be all the more concerning, given the assumption among Thomists that Darwin has not really dealt the deathblow to our
philosophy of nature. Fortunately, Umphrey fills this lacuna and thereby offers
a good assessment of “what happened” among philosophers of nature toward
the elimination of the everyday view that dogs really are one kind of thing—
and by the way, ants are another, and elms and planets a third and fourth.
Umphrey’s work is a historical companion to his more topical treatment of
the same subject, Natural Kinds and Genesis: The Classification of Material
Entities (Lanham, Md.: Lexington Books, 2016). There, he argues that although
contemporary science seems to eliminate the idea that any species of organism
is a natural kind, it “does not make it easy to decide that there are, or are not,
natural kinds” altogether, leaving open the possibility that molecular
compounds could be an example (13). Although, for a student of St. Thomas,
this conclusion sacrifices too much—particularly when Umphrey simply grants
that there are no species of organisms that “form disjoint classes in virtue of
their intrinsic natures” (11)—the aim in both books is to “pave the way for . . .
a renewal” of natural philosophy in the face of both “protometaphysical
antirealism” and “philosophical naturalism” about natural kinds (17), an aim
the perennial philosophy would support. In spite of being a companion to the
2016 volume, this newer volume can easily be read on its own, in part thanks
to Umphrey’s substantial review of the earlier work in his prologue. His
language for describing natural kinds, especially in the prologue, may be a bit
foreign to a student of Aristotle and the medievals—indicating an analytic
influence and perhaps rooted in Umphrey’s inclination to view old natural-kinds
realism in light of the new—but his frequent references to “continuants,”
“dividuals,” “grades of worldly involvement,” “singleton,” “disjoint,” and “sresemblance classes” are usually explained without residual obscurity. The book
is divided into seven chapters, the first two on the precursors to Aristotle’s
natural kinds (the pre-Socratics and Plato), the second two on Aristotle’s theory
and the Christian and Scholastic incorporation of it that also began its
unraveling, and the last three on its demise in modern philosophy of nature
(especially Galileo, Bacon, Descartes, Locke, Newton, Kant, and Darwin).
In the first chapter, Umphrey concludes that, although the earliest Greek
poets and pre-Socratics had a notion of nature and “have some idea of kinds
. . . they seem unaware of natural kinds as such” (24). The later pre-Socratics
were less uniform: Anaxagoras allowed “no individual continuants and no
natural kinds in the primary sense” (39), whereas the atomists “were the first
natural philosophers to admit individual continuants” (40), the atoms, but were
ambiguous about natural kinds for these atoms, and Empedocles offered “the
first evidence of philosophical reflection on natural kinds” (43). One of
Umphrey’s points in the first chapter is that although Aristotle’s view of natural
kinds “has its native home in everyday thought” (2), his “bio-centric” (15)

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replacement of the pre-Socratic views, all of which in one way or another
rejected natural kinds, was itself revolutionary, equal in gravity only to the neopre-Socratic reinstatement of this rejection in the modern era.
The second chapter discusses Plato. While we find the forms in Plato first, a
step toward natural kinds, Umphrey offers a somewhat unusual interpretation
of Socrates as not quite asserting the “forms as beings,” and uncommitted about
whether they are “immanent in things” or “transcendent” (47); likewise, “we
cannot be sure” (a persistent refrain in this chapter) that the kinds we find in
the Timaeus should “be regarded as natural” (67). Plato “entertained seriously”
both the reality of types and the possibility that they “are artificial or
conventional rather than real” (75). Ultimately, Umphrey concludes, Plato
“was, it seems, non-dogmatically and self-consciously a natural-kinds antirealist” (77). However, Umphrey does not posit mere discontinuity between
Plato and Aristotle—he entitles both chapters 2 (on Plato) and 3 (on Aristotle),
“Eidos and Genesis.” Rather, he thinks that, in positing natural kinds, Aristotle
was in a sense following his teacher (and his teacher) by turning to “invariant
forms and their definitions, together with the Socratic-Platonic insistence that
we pay close attention to what is first for us” (15).
That critical third chapter is a grand sweep of Aristotle’s natural philosophy
and metaphysics, explaining both his embrace of natural kinds and the tensions
within this embrace. Aristotle recognized that what is “first for us” is not only
found in “the ways in which people talk about things” (79) but also among the
natural phenomena that we experience. Thus, even though his Physics begins
with a proposal to found the science on the more known to us, he must spend
the entire first book of the Physics refuting or appropriating his predecessors’
views of nature because of their tendency to “denigrate our everyday
understanding of things” (81). And since what are first for us are living things,
here Aristotle seems most confident about natural kinds, whereas the very
substantiality of elements (for example) is, in Umphrey’s estimation, somewhat
ambiguous. Likewise, positing both the celestial matter, “the most revisionary
consequence of Aristotle’s cosmological perspective” (99), and the “supranatural” God, “the most revisionary consequence of Aristotle’s theological
perspective,” is “sketchy” (100) and has “a conjectural air” (102). The uncertainty in both cases derives from Aristotle’s “Odyssean” (103) circumspection and a resistance to “the temptation to reduce what is right before us to
what is far away, or to systematize his various findings and conjectures” (1023). As regards the reality of Aristotle’s natural kinds, Umphrey admits that there
have been multiple interpretations (depending on how one understands the
extramental reality of universals) and points out troubles for the view that
Aristotle was an “immanent realist” (106), suggesting that he implicitly admitted
a certain “moderate antirealism.” With Darwin clearly in mind, Umphrey’s most
serious problem with Aristotle’s view, however, centers around reproduction
and spontaneous generation; both the instrumentality of seed and the possibility
of generation without seed seem to make the continuity of species open to

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doubt, and his biology more “seems to favor” the possibility that “small eidetic
variations might accumulate over generations” (117). Thus, Aristotle’s “genetic
account” of species “does not square with his . . . eidetic account,” and this
could “lead one to reject [animal] species as natural kinds, and even to doubt
that substantial forms could . . . explain the existence of continuants” (ibid.).
Scholasticism’s wholehearted acceptance of natural-kinds realism, the subject
of the fourth chapter, is a mixed blessing according to Umphrey, since creation
in Christian revelation “[undercuts] . . . Greek distinctions between nature and
history, natural and conventional, natural and sacred” (123). Umphrey follows
the Averroist reading of Aristotle where the human soul is in no way immortal
and God “cares not at all about the natural world” (127), a reading that is
debatable but not unheard of. But this is a strange chapter in some ways, both
because of a number of misreadings of St. Thomas Aquinas—for instance,
Umphrey’s Aquinas claims “you are essentially your soul” (126) and “your
essence . . . [is] your intellect” (ibid.)—and mistaken assessments of Christian
theology—which he says raises “obedience above contemplation” (124) and
wherein Christ is “doubtfully . . . the same natural-kind type as those around
him” (129). Some of these mistakes or debatable claims matter to the argument,
since from them Umphrey concludes that Aquinas’s “synthesis of Aristotelian
philosophy with Christian doctrine is unstable” (126). Umphrey is particularly
insightful, however, in pointing out that Ockham’s well-known problems with
natural kinds arose from his “focus first of all not on what exists but on our
ways of apprehending what exists” (135), such that he ends up with “at most
one natural kind in the primary sense of the term,” material things (139).
In chapters 5 and 6, both entitled “Lex and Motus,” we see a new perspective
on the story of the rejection of Aristotelian natural philosophy and the
mathematization of nature in the age of Galileo, Descartes, and Newton.
Umphrey attends to the implications of the “metaphysical foundations” (146)
of this paradigm shift and therefore to the philosophers most involved
(especially Descartes, Locke, Leibniz, and Kant). As a result, the centrality of
the matter of natural kinds becomes clearer. We find the early moderns
mathematizing nature because of their stress on the image of nature as a
machine, while also trying in various ways to shake off the corollary that nature
has ends because all machines have ends—some saying that the ends are real but
in the inscrutable mind of God (Descartes), others that they are just heuristic
scaffolding, to be jettisoned when their ateleological account is discovered
(Kant). Likewise, the moderns’ description of nature through laws (which
replace Aristotle’s forms), Umphrey notes, leans heavily on their “biblical or
theological” worldview (158). Umphrey himself doubts, however, that “the
reality of such laws” logically implies that they have “been legislated” (159), as
many modern physicists would agree. Umphrey points out the basic unanimity
about natural kinds in the modern paradigm shift: from Descartes to Bacon to
Hobbes to Boyle to Locke, we find that natural kinds and even continuants are
either “superfluous” or “idols” (161), merely Ockhamist “nominal essences”

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(185). In particular, Descartes finds himself stuck. He “must, it seems, affirm as
well as deny the existence of at least one natural kind,” us (180). In a
surprisingly lengthy discussion of Kant’s role in the debate about natural kinds
in biology, final causes and species are useful fictions. This is a bridge to Darwin,
as Umphrey finds “our timeless logical ‘tree’ featuring typological speciest”
being gradually replaced by “the real historical ‘tree’ featuring genealogical
speciesg” (211). Thus, “Kant . . . refined and deepened the problem implicit in
Descartes’s view of man’s hyphenated nature,” and although many philosophers
then took this in new directions, “in no case did it renew interest in natural
kinds” (216).
With Darwin’s On the Origin of Species, the subject of the final chapter,
natural kinds are dropped “into the dustbin of metaphysical curiosities” (ibid.).
Darwin managed to do what the Galilean natural philosophers could not, for in
elevating the machine as the paradigm for all of nature they had to ignore or
offer a postdated check to biology, since physics made only modest progress in
reducing life to mechanism. Darwin’s theory, however, offered hope insofar as
it implied that the animate might arise from the inanimate just as (he argued)
one species could evolve from another. In spite of using “a relaxed view” (225)
of laws of nature and offering what is essentially “an historical discipline” (227)
with “very little predictive power” (225), Darwin understood himself as
modeling “his theory on Newton’s mechanics” (228-29), for again “biological
species [are] nominal essences . . . more or less arbitrarily delimited” (229). At
length, Umphrey defends the argument of On the Origin of Species, giving
special attention to the charge that Darwin is inconsistent, even incoherent,
about the reality of species, natural kinds. The strategy of the book, Umphrey
argues, is to replace species as a class with a common form (“typological
species”) with species as a group with a common ancestor (“genealogical
species”), where even a “genus” is now nothing more than that common
ancestor. Thus, Umphrey admits, “race” is more the word Darwin should be
using (229), but his equivocal use of “species” is part of the dialectic against
“creationists” (233). Umphrey grants, however, that Darwin appears not to
“have a well-defined species-concept,” and wonders whether such a concept
that does not simultaneously imply “that there is something special about
species that makes them different in kind from other taxa” (ibid.) is even
possible for Darwin’s account. For “by ‘historicizing’ these natural kinds he was
not modifying them but setting them aside” (230), and these different groups
of animals only “seem to differ in kind from one another” (231). Likewise,
Darwin copes with the fact that “we humans think we are special . . . [by]
subjecting this prejudice to mild ridicule” (235-36), though he seems to end up
“a property dualist” and to “[make] little effort to clarify his position or defend
it against physicalistic and behavioristic alternatives” (239). Indeed, Umphrey
points out that “Darwin’s theory does not require that” organisms even “be
genuine continuants” (234). So, the condition for the possibility of a natural
kind is also on the chopping block now.

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BOOK REVIEWS

This book is full of remarkable asides, dangling questions, and provocative
insights, especially in its final pages on natural philosophy after Darwin. A
salient example: Umphrey indicates that with the elimination of natural kinds,
the question “What is man?” and others like it must be set aside, since “these
questions presuppose that mant [i.e., as a kind] exists, or that there is such a
thing as human nature, and these presuppositions Darwin rejects. Instead he
asks how mang [i.e., the genealogical species] originated” (235). This change
from the “what is man?” to the “how is man?” profoundly clarifies the
difference in spirit between classical and modern philosophical/scientific
inquiry. Similarly, Umphrey cagily puzzles over our instinct that there are
natural kinds, on the one hand deriving it from evolution’s “fundamentally
pragmatic” attention to the useful and advantageous (242), but on the other,
pointing out that we then need “an evolutionary psychology of natural
philosophy” (243). For such a subdiscipline would somehow have to explain
the origin of an animal that “[wants] to know what there is, and why, quite
apart from any practical benefit such knowledge may bring”: beings, in other
words, that contemplate “not only for life but for the truth” and that “offer and
appraise arguments of the sort presented in this book” (244). That is, although
Umphrey seems to have no doubts about the fundamental truth of Darwin’s
theory—he claims that from it, “terrestrial life may at last be seen aright, as it is
in reality” (230), adding at one point that “there is little prospect of a return to
Aristotelian speciest” (234)—questions still remain, and more work must be
done. As he says in the introduction, this “is not so much a detailed history . . .
as it is a series of soundings, or excavations, which together reveal in outline
the full story yet to be told” (14). This is not only because of the aforementioned
“new scientific essentialism” implicit “in chemistry and atomic physics” (235)
but also because these “questions . . . cannot be answered by cognitive science
or common sense alone” (243). These and other speculations, combined with
Umphrey’s frequent but always passing references to contemporary science, are
stimulating and motivate one to take a look at Natural Kinds and Genesis for
deeper consideration.
CHRISTOPHER A. DECAEN
Thomas Aquinas College
Santa Paula, California