The Thomist 68 (2004): 343-73

SAINT AUGUSTINE ON CONJUGAL LOVE
AND DIVINE LOVE
PERRY

J. CAHALL

Ohio Dominican University
Columbus, Ohio

N

O PATRISTIC THEOLOGIAN has had a greater impact on
Western Christianity than St. Augustine of Hippo.
Wherever one goes in Western Christian intellectual
tradition Augustine has been there already and has often laid the
foundations for further reflection on the topics he addressed. One
facet of St. Augustine's wide-ranging thought that has proved to
be foundational for Western Christianity is his theology of
marriage and sexuality. David Hunter has aptly written, "No
Christian writer has exerted greater influence on the development
oi the Western theology of marriage than Augustine. " 1
The popular view is that Augustine has bequeathed to Western
Christianity a highly negative view of conjugal life. Much modern
scholarship has criticized Augustine for a supposed negative view
of human sexuality and consequently a deficient view of marriage
and marital love. 2 Several scholars have accused Augustine of
1 David Hunter, "Augustine and the Making of Marriage in Roman North Africa," Journal
of F.arly Christian Studies 11.1 (2003): 64.
2 Examples include: David F. Kelly, "Sexuality and Concupiscence in Augustine," in The
Annual of the Society of Christian Ethics, ed. Larry L. Rasmussen (Waterloo, Ontario, Canada:
Council on Study of Religion, 1983), 81-116; David M Thomas, Christian Marriage: A
Journey Together, Messages of the Sacraments5, ed. Monika K. Hellwig (Collegeville, Minn.:
The Liturgical Press, 1983), 55; James A. Brundage, Law, Sex, and Christian Society in
Medieval Europe (Chicago: University of Chicago Press, 1987), 80-82; John Mahoney, The
Ma/Ung of Moral Theology (Oxford: Clarendon Press, 1987), 45; Paul Ramsey, "Human
Sexuality in the History of Redemption," in The Ethics of St. Augustine, ed. William S.
Babcock, Journal of Religious Ethics Studies in Religion 3 (Atlanta: Scholars Press, 1991),

343

344

PERRY J. CAHALL

being opposed to sexual attraction, sexual intercourse, and sexual
pleasure. 3 Some claim that his view of sexuality may even have
been tainted with latent Manichaeism. 4 Others have accused him
of maintaining a functionalist view of sexual intercourse according
to which the conjugal act is legitimated only by procreation and
has no value as an expression of love between the spouses. 5
However, a number of scholars have pointed out positive
aspects of Augustine's theology of marriage. 6 In particular, several
115-45.
3 John T. Noonan, in his celebrated book Contraception: A History of Its Treatment by the
Catholic Theologians and Canonists (Cambridge, Mass.: Harvard University Press, 1965), said
that Augustine's understanding of marriage possesses Manichean and Stoic influences (166).
Andrew Greeley has said that married couples in Western Christianity and especially in
Roman Catholicism are living in the shadow of St. Augustine's negative view of sexuality
("Sex and the Married Catholic: The Shadow of St. Augustine," America 167 [1992]: 318).
Theodore Mackin maintains that despite what Augustine claimed, for him "intercourse itself
was sinful" ("Augustine on the Nature of Marriage," in Sexuality, Marriage, and the Family:
Readings in the Catholic Tradition, ed. Paulinus Ikechukwu Odozor [Notre Dame: University
of Notre Dame Press, 2001], 173). Uta Ranke-Heinemann has leveled one of the most virulent
attacks on St. Augustine's view of marriage and sexuality in her book Eunuchs for the IGngdom
of Heaven: Women, Sexuality, and the Catholic Church (New York: Penguin Books, 1991).
She calls Augustine's conversion "a disaster for married people" (78), and says that Augustine
was "the man who fused Christianity together with hatred of sex and pleasure into a
systematic unity" (75).
4 For examples of this critique see Bernard Haring, Free and Faithful in Christ, vol. 1
(1979), 512-14; Thomas C. Fox, Sexuality and Catholicism (New York: G. Braziller, 1995),
22; Vincent J. Genovesi, In Pursuit of Love: Catholic Morality and Human Sexuality
(Collegeville, Minn.: The Liturgical Press, 1996), 116-18.
5 Eric Fuchs has contended that "although he was more sensitive than others to the social
dimensions of the couple, [Augustine] was unable to conceive of the possibility that sexuality
could hold tenderness, friendship, spirituality, and this lack of insight was very influential on
the later tradition" (Sexual Desire and Love: Origins and History of the Christian Ethic of
Sexuality and Marriage, trans. Marsha Daigle [Cambridge: James Clarke & Co., 1983], 117).
Theodore Mackin contends that Augustine left no middle ground between conception and
capitulation to sexual lust for couples to engage in sexual intercourse as an expression of
intimacy ("Augustine on the Nature of Marriage," 172). John T. Noonan maintains that
Augustine saw procreation as the purpose of marriage (Contraception, 151) and that he saw
"selfless love" as having a very small part in marriage (152). Uta Ranke-Heinemann holds that
for Augustine "intercourse is a culpable act and needs justification: a child" (41), and she goes
on to call Augustine a neurotic who "radically separates love and sexuality" (Eunuchs for the
IGngdom of Heaven, 76).
6 Examples of this scholarship include: Emile Schmitt, Le mariage chretien dans /'oeuvre
de Saint Augustin. Une theologie baptismale de la vie conjugale (Paris: Etudes Augustiniennes,
1983); Augustine Regan, "The Perennial Value of Augustine's Theology of the Goods of

CONJUGAL LOVE AND DMNE LOVE

345

have noted the importance of friendship and love in Augustine's
theology of marriage,7 highlighting a more personalist dimension
of his thought on marriage than he is often given credit for.
Building on this scholarship, I have argued that the three goods of
marriage that Augustine delineated (procreation, fidelity, and the
sacrament) are inseparable aspects of marital love that present us
with at least a limited analog to the love of the Trinity. 8 I have
also argued that Augustine's writings on marriage should be read
in light of his Trinitarian theology, in which we find some of his
most deeply held theological convictions. 9 In the present article,
I wish to show how Augustine's theology of the Trinity provides
a means for elaborating his vision of conjugal love, since for
Augustine the life of the Trinity is the source of all true love,
including the love between spouses.
Marriage," Studia Moralia 21 (1983): 351-78; John R. Connery, "The Role of Love in
Christian Marriage: A Historical Overview," Communio 11 (1984): 244-57; Cormac Burke,
"St. Augustine and Conjugal Sexuality," Communio 17 (1990): 545-65; Donald Burt,
"Friendship and Subordination in Earthly Societies," Augustinian Studies 22 (1991): 83-124;
Robert}. O'Connell, "Sexuality in Saint Augustine," in Augustine Today, Encounter Series 16
(Grand Rapids, Mich.: Eerdmans, 1993), 60-87; David G. Hunter, "Augustinian Pessimism?
A New Look at Augustine's Teaching on Sex, Marriage and Celibacy," Augustinian Studies 25
The Bond of
(1994): 153-77; Carol Harrison, "Marriage and Monasticism in St.
Friendship," Studia Patristica 33 (1997): 94-99; Willemien Otten, "Augustine on Marriage,
Monasticism, and the Community of the Church," Theological Studies 59 (1998): 385-405;
Mathijs Lamberigts, "A Critical Evaluation of Critiques of Augustine's View of Sexuality," in
Augustine and His Critics, ed. Robert Dodaro and George Lawless (New York: Routledge,
1999), 176-97.
7 Donald Burt, Friendship and Society: An Introduction to Augustine's Practical Philosophy
(Grand Rapids, Mich.: Eerdmans, 1999), 83; ibid., "Friendship and Subordination in Earthly
Societies," 83, 95; Connery, "The Role of Love in Christian Marriage," 245; Hunter,
"Augustinian Pessimism?", 160; Otten, "Augustine on Marriage, Monasticism, and the
Community of the Church," 398, 404.
8 Perry J. Cahall, "The Trinitarian Structure of St. Augustine's Good of Marriage,"
Augustinian Studies 34:2 (2003): 223-32.
9 Perry J. Cahall, "Saint Augustine on Marriage and the Trinity," Josephinum Journal of
Theology 11.1 (Winter/Spring 2004): 82-97. Denis Faul suggested such a contextualization
of Augustine's theology of marriage some thirty-seven years ago when he said that Augustine's
theology of marriage and sexuality should be viewed in light of his deepest theological
insights, including those regarding the Trinity, creation, the image of God in the human
person, and humanity before the fall ("Saint Augustine on Marriage: Recent Views and a
Critique," Augustinus 12 [1967]: 166).

346

PERRY J. CAHALL

I maintain that Augustine articulates sound principles and
perennial insights for understanding and living out the mystery of
married love in all its facets. Furthermore, I believe that a
contextualized reading of Augustine's works on marriage shows
us that spouses are called in their conjugal love to participate in
the divine order of love. An indispensable part of this context is
his Trinitarian theology. Although Augustine himself did not draw
an explicit link between his theology of the Trinity and his
theology of marriage, 10 we can allow these different strands of
Augustine's thought to inform each other, and thus arrive at a
more complete picture of conjugal love. In particular, implied and
in many ways assumed in Augustine's writings is a vision of
conjugal love that is nourished by and participates in the mystery
of Trinitarian love. This vision applies to all areas of conjugal life,
including the spouses' conjugal embrace. Thus, Augustine shows
modern man that sex is for more than mere pleasure. The
conjugal embrace is called to participate in divine love.
I. AUGUSTINE ON SEXUAL DESIRE

In order to understand God's design for sex and marriage,
Augustine referred to man's prelapsarian state as outlined in the
Book of Genesis. Augustine held that before the Fall all human
passions and emotions would have been ordered according to the
ordinance of reason and would have been subject to the control
of the will. Adam and Eve would have experienced sexual desire
as completely subject to the control of their reason and will. 11
10 That Augustine did not draw this connection explicitly should not be surprising, since
he was not a systematician in the modern sense of the word and since most of his writings,
including his writings on marriage, are produced in response to specific controversies and
questions. Nonetheless, there is a consistency in his thinking that is the result of certain core
theological principles. Peter Brown, in one of the appendices to the new edition of his
celebrated biography of St. Augustine, admits that Augustine's thought is more "of a piece"
than he had once thought {Peter Brown, Augustine of Hippo: A Biography [2d ed.; Berkeley:
University of California Press, 2000), 490).
11 DecivitateDei14.23 {writtenaround418/419)
;DeGenesiadlitteram9.3-4;10 {begun
around 401 and completed around 415); De gratia Christi et de peccato originali 2.35.40
{written in418); De nuptiisetconcupiscentia 2.7.17; 2.22.37; 2.31.53 {written around41921); Contra Iulianum opus imperfectum 5.16 {written around 429/43 0 and left unfinished at

CONJUGAL LOVE AND DIVINE LOVE

347

Peter Brown says that, according to Augustine, "In Adam and
Eve's first state, sexual desire was not absent, but it coincided
perfectly with the conscious will: it would have introduced no
disruptive element into the clear serenity of their marriage. " 12
Augustine saw that this condition changed radically after the Fall:
a comparison of Genesis 2:25 and Genesis 3:7 shows that Adam
and Eve only experienced shame at their nakedness after the
Fall. 13
It is crucial to realize that Augustine maintained that in our
present fallen state our passions tend towards disorder as an effect
of original sin-a sin which he did not see as having been
motivated by sexual attraction. 14 The first sin of humanity was an
act of disobedience to God, and as a result of it men's and
women's desires no longer obey them without effort. Rupturing
the original order of God's creation has resulted in an interior
disorder for man. 15 Augustine saw sexual lust as a prime example
of the disorder present in humanity's postlapsarian desires, 16
evidence of the. fact that when Adam and Eve ceased fully to obey
God's will out of love their desires ceased fully to obey their own
wills. 17 It is for this reason that Augustine refused to give
unqualified praise to sexuality as humanity now experiences it. 18
the time of Augustine's death). All dates for Augustine's works are taken from Augustine
through the Ages: An Encyclopedia, ed. Allan D. Fitzgerald (Grand Rapids, Mich. : Eerdmans,
1999).
12 Peter Brown, The Body and Society: Men, Women, and Sexual Renunciation in Early
Christianity (New York: Columbia University Press, 1988), 402-3.
u De civitate Dei 13.13; 14.17; De Genesi ad litteram 9.10.16; De gratia Christi et de
peccato originali 2.36.41; De nuptiis et concupiscentia 1.6.7; Contra duas epistulas
pelagianorum 1.16.32 (writtenin421); Contraiulianum4.16.82 (writtenin421/422); Contra
Iulianum opus imperfectum 3.74; 4.36.
14See De Genesi ad litteram 11.41.57; Contra Iulianum 6.22.68.
15 See Mathijs Lamberigts, "Julien d'Eclane et Augustin d'Hippone: Deux conceptions
d' Adam," trans. J. van Houtem, in Collectanea Augustiniana. Melanges T. ]. Van Bavel, ed. B.
Bruning, M. Lamberigts, and J. van Houtem, Bibliotheca Ephemeridum Theologicarum
Lovaniensium 92, vol. 1 (Leuven: Leuven University Press, 1990), 404-5.
16 Ibid., 405.
17 Peter Brown, "Augustine and Sexuality," in Augustine and SeXuality: Protocol of the 46rh
Colloquy (Berkeley: Center for Hermeneutical Studies in Hellenistic and Modern Culture,
1983), 10.
18 Robert Innes, "Integrating the Self through the Desire of God," Augustinian Studies 28.1
(1997): 76.

PERRY]. CAHALL

348

In discussing the state of fallen humanity Augustine wrote at
length about different forms of desire or concupiscence, 19 among
which he included carnal concupiscence (concupiscentia carnis).
The idea of carnal concupiscence, or desire of the flesh, comes
from Galatians 5: 17, where St. Paul speaks of the flesh lusting
against the spirit. Augustine used this term to refer to the tendency of all our sensitive appetites, including sexual desire, to
escape the control of reason. 20 In his disputes with his Pelagian
adversary, Julian of Eclanum, Augustine took great pains to distinguish between carnal concupiscence that consists of a disordered
desire for any sensual pleasure (including sexual lust) and
sexuality as such with its attendant pleasure: "You do not know,
or pretend not to know that the quality, the usefulness, and the
19 For a good, brief discussion of different kinds of concupiscence that Augustine posits see
Mathijs Lamberigts, "Augustine, Julian of Aeclanum and E. Pagels' Adam, Eve, and the
Serpent," Augustiniana39 (1989): 407-13, SeealsoJamesB. Weidenaar, "Augustine's Theory
of Concupiscence in City of God, Book XIV," Calvin Theological journal 30 (1995): 52-74;
Weidenaar also provides a good discussion of the distinctions Augustine makes when speaking
about concupiscence (although his discussion differs somewhat from that of Lamberigts).
Weidenaar makes the valuable observation: "We must first keep in mind that Augustine's
primary goal in formulating most of his thoughts about concupiscence ••• was not to provide
a Christi:>n ethic of sex. He wrote in a context in which the Pelagian ideas about free will and
sin seemed to be undermining the importance of the need for grace" (67-68). A more
extended discussion of Augustine's concept of concupiscence and the evolution of his
understanding ofit can be found in Fran1;ois-Joseph Thonnard, "La notion de concupiscence
en philosophic augustinienne," Recherches Augustiniennes 3 (1965): 59-105; and Emile
Schmitt, Le mariage chritien dans /'oeuvre de Saint Augustin. Une tbeologie baptismale de la
vie conjugale (Paris: Etudes Augustiniennes, 1983), 96-105. A very helpful work that deals
with Augustine's concept of concupiscence and the different types of concupiscence that he
delineates is Jon T. Beane, "The Development of the Notion of Concupiscence in Saint
Augustine" (Ph.D. diss., University of Notre Dame, 1993).
2 Contra Iulianum 4.14.74; See Contra Iulianum 4.13, 14 where Augustine addresses
carnal concupiscence at length. See M Lamberigts, "Some Critiques on Augustine's View of
Sexuality Revisited," Studia Patristica 33 (1997): 156. Lamberigts has focused specifically on
reevaluating the debate between Augustine and Julian of Eclanum over the concept of the
concupiscence of the flesh (concupiscentia camis). See also Lamberigts, "A Critical Evaluation
of Critiques of Augustine's View of Sexuality," 176-97. Another article that lends support to
Lamberigts's insights is G. I. Bonner, "Libido and Concupiscentia in St. Augustine," Studia
Patristica 6 (1962): 303-14. See also John Rist, "Appendix 3: Augustine and Julian: Aspects
of the Debate about Sexual concupiscentia," in Augustine: Ancient Thought Baptized
(Cambridge: Cambridge University Press, 1994). For a good discussion of the differing views
of Augustine and Julian regarding the original state of human existence see also Lamberigts,
"Julien d'Eclane et Augustin d'Hippone: deux conceptions d' Adam."

°

CONJUGAL LOVE AND DIVINE LOVE

349

necessity of sensation through a sense of the body are not the
same as lust [libidinem] for this sensation. " 21 He clearly
distinguishes between sensual pleasure and carnal concupiscence
(carnis concupiscentiam) that includes sexual lust when he says
that "pleasure can also be honest ... it is concupiscence of the
flesh or lust [libidinem]which is shameful. " 22 This statement alone
is ·enough to show that Augustine did not have an inherent bias
against sexual pleasure. It is true that he commented little on how
this pleasure contributes to or factors into a couple's relationship,
but this is a modern preoccupation that Augustine should not be
faulted for failing to address.
Julian of Eclanum tended to equate carnal concupiscence,
sexual lust, and sensual pleasure, and therefore he refused to
admit that carnal concupiscence and sexual lust were results of the
Fall. Instead, Julian maintained that carnal concupiscence was
necessary in order for procreation to take place and thus held that
. it is a naturally good part of the human condition. 23 In contrast to
Julian, Augustine notes that in this life sexual intercourse is never
completely free of the disordered effects of carnal concupiscence. 24 It is this insight-that human sexual desire is now such
that it resists the control of reason and will-that causes many
modern theologians and others to revile Augustine.
On this point Augustine can be faulted for not properly
distinguishing between an act directed by reason and an act
performed according to reason. 25 Saint Thomas Aquinas would
21 Augustine, Against Julian [Contra]ulianum], trans. Matthew A. Schumacher, Fathers of
the Church 35 (Washington, D.C.: The Catholic University of America Press,1957), 4.14.65
(PL 44:769-770). See also Contra Iulianum opus imperfectum 4.69.
22 Augustine, De nuptiis et concupiscentia 2.9.22 (CSEL 42:274): "potest uoluptas et
honesta esse ..• camis concupiscentiam uel !ibidem, quae pudenda est" (translation mine). I
think Roland Teske's translation of this passage is imprecise, which reads: "pleasure can also
be morally good •.• concupiscence of the flesh or sexual passion ••• is something to be
ashamed of" (Marriage and Desire, Works of Saint Augustine 1/24 [New York: New City
Press, 1998], 2.9.22]. I believe "lust" rather than "sexual passion" is a more accurate rendering
of /ibidem.
23 Contra Iulianum 4.3.21; 4.14.65.
24 De nuptiis et concupiscentia 2.32.54; Contra Iulianum 3.21.43; 5.9.37, 39.
25 Laura L Garcia provides an excellent discussion of this distinction in "Christians and
the Joy of Sex," The National Catholic Bioethics Quarterly 3:2 (Summer 2003): 259-61.

PERRY J. CAHALL

350

later make such a distinction, pointing out that certain acts, like
sleeping, although they are not directed by reason at every
moment can be entered into according to reason. 26 This same
distinction would apply to the act of sexual intercourse, which
although subject to emotional and physical reactions and
responses that are not directed by reason can still be undertaken
according to reason. However, even though Augustine failed to
make this distinction, surely his insight regarding the tendency of
fallen sexual desire to resist the control of reason and will
deserves to be acknowledged. Such an acknowledgment could go
a long way to cultivating a more realistic view of sex in a day and
age that is obsessed with sex, encourages satisfying any and all
sexual desires, and manufactures unrealistic expectations
surrounding the satisfaction of these desires.

II. A GOOD CONCUPISCENCE OF
MARRIAGE AND SEXUAL INTERCOURSE

While Augustine wrote more frequently about negative forms
of concupiscience, toward the end of his life, in his debates with
Julian of Eclanum, he also posited several types of positive
concupiscible desire, such as a natural desire for spiritual goods
(concupiscentia spiritus), 27 including the goods of wisdom
(concupiscentia sapientiae)28 and happiness (concupiscentia
beatitudinis). 29 He even allowed for the possibility that a good
type of carnal concupiscence or desire of the flesh could have
existed in paradise, one that would have followed the dictates of
the wills of the first spouses. 30 He also spoke of a good
Theologiae II-II, q. 153, a. 2.
4.14.72; Denuptiisetconcupiscentia 2.30.52. Lamberigtshassaid that
the essence of good concupiscence for Augustine is "a longing for God's gift of love" ("Some
Critiques on Augustine's View of Sexuality Revisited," 157).
28 Contra Iulianum 4.3.17; De nuptiis et concupiscentia 2.10.23; 2.30.52.
29 Contra Iulianum opus imperfectum 4.67; See also Contra duas epistolas Pelagianorum
2.8.17; 2.9.21 where Augustine references a desire for good things (cupiditas bani).
3 °Contra Iulianum 5.5.22; Contra Iulianum opus imperfectum 2.42.45; 3.177; 5.13.16;
6.14.22.
26 Ibid.; See Summa

27 Contralulianum

CONJUGAL LOVE AND DMNE LOVE

351

concupiscence (bona concupiscentia) in marriage that sublimates
the desire for sensual pleasure to the desire for offspring. 31
In Epistula 6*, a letter from late in his life, Augustine posits the
possibility of a good carnal concupiscence:
Therefore this concupiscence of the flesh, if it existed in paradise so that by
means of it children were begotten to fulfill the blessing of marriage by the
multiplication of human beings, was not the same kind of carnal concupiscence
we experience now, when its movements covet indifferently what is licit and
illicit.... But if concupiscence had existed in paradise, it would have to be of a
different type, in which the flesh would never have lusted against the spirit [Gal
5:17]. 32

In this same letter Augustine speaks of a "concupiscence of
marriage" (concupiscentia nuptiarum) that would have existed in
paradise to maintain the peaceful love of the spouses. 33 Regarding
this concupiscence of marriage Augustine writes, "What Catholic
would call the carnal desire present in marriage [concupiscentiam
nuptiarum] the work of the devil, since by means of it the human
race would have been propagated even if no one had sinned. "34
He goes on to distinguish several aspects of this concupiscence of
marriage:
Because of this error they [the Pelagians] do not distinguish the concupiscence
associated with marriage, i.e. the concupiscence of conjugal purity,
concupiscence for the legitimate engendering of children, or the concupiscence
of the social bond by which each sex is tied to the other, from the concupiscence
of the flesh which hankers after the illicit as well as the licit indifferently and
through the concupiscence of marriage which uses it well is restrained from the
illicit and permitted only the licit.35

What is significant about this passage is that each aspect of the
marital concupiscence that Augustine is delineating represents a
desire for one of the goods of marriage that he distinguished:
31 Contra Iulianum 5.16.63;

6.16.50.
Robert B. Eno, Fathers of the Church 81 (Washington, D.C.:
The Catholic University of America Press, 1989), 8 (CSEL 88:38) (written around 420)
33 Ibid.,7 (CSEL 88:36).
34 Ibid., 3 (CSEL 88:33).
35 Ibid.,5 (CSEL 88:34).
32 Letter [Epistula] 6\ trans.

352

PERRY J. CAHALL

offspring (proles), fidelity <fides), and the sacrament (sacramentum). 36 The "concupiscence of conjugal purity" appears to
represent the good of fidelity by signifying a desire for exclusive
union in which each spouse supports the other, body and soul.
The "concupiscence for the legitimate engendering of children"
is obviously a reference to the good of procreation. Finally, the
"concupiscence of the social bond by which each sex is tied to the
other" would seem to be a reference to the desire for the
indissoluble sacramental bond of marriage which binds the
spouses together and provides the basis for society.
It is significant that Augustine sees each of these three desires
as constitutive of the desire for marriage ("the concupiscence
associated with marriage"). He illustrates that the three goods of
marriage are really not separable goods, but are instead together
the triune good that is marriage. 37 To desire marriage means to
desire its triune good with this threefold concupiscence of
marriage. One who desires marriage cannot separate any of the
three goods from marriage. To attempt to do so would be to
desire something other than marriage.
Further, it is noteworthy that the threefold desire for marriage
that Augustine proposes in Epistula 6* can be seen to refer
simultaneously to the desire for sexual intercourse. Regarding the
passage from this letter quoted above, Donald Burt posited, "In all
of these cases 'concupiscence' represents the desires of a spirit in
a body and in at least two of them (the desire for procreation and
the desire for union of the spouses) it involves a sexual desire
which clearly is not disreputable. "38 I would go further to say that
Emile Schmitt, Le mariage chretien dans /'oeuvre de Saint Augustin. Une theologie
baptismale de la vie conjugale (Paris: Etudes Augustiniennes, 1983), 232-33, provides a
chronological listing of Augustine's works in which he refers to the three goods of marriage:
De bono coniugali 3.3-7.7; 24.32 (written in 401); De sancta virginitate 12.12 (written in 401
as a companion piece to De bono coniugal1); De Genesi ad litteram 9.7.12; De bono viduitatis
4.5 (written in 414); De gratia Christi et de peccato originali 2.34.39; 37.42; De nuptiis et
concupiscentia 1.10.11; 1.11.13; 1.17.19; 1.21.23; Contra Iulianum 2.7.20; 3.16.30;
36

3.25.57; 5.12.46.
37 On this point see Cahall, "The Trinitarian Structure of St. Augustine's Good of
Marriage," 229-32.
38 Burt, Friendship and Society, 114.

CONJUGAL LOVE AND DNINE LOVE

353

all three aspects of this desire for marriage can be seen as referring
to sexual desire if one sees the "concupiscence of conjugal purity"
as referring to the upright desire for sexual union wherein the
spouses render faithfully to each other, and to no one else, the
conjugal debt according to the virtue of chastity. 39
III. THE CONJUGAL EMBRACE AT THE SERVICE OF
CONJUGAL LOVE

It should not go unnoticed that, by delineating a threefold
concupiscence of marriage that simultaneously refers to the three
goods of marriage and the desire for sexual intercourse, Augustine
places sexual relations within the context of the triune good of
marriage. The logic of Augustine's thought suggests that sexual
intercourse and sexual desire must simultaneously be at the service
of procreation, fidelity, and indissolubility. The sexuality and the
sexual desires of spouses are to serve the triune good of marriage
whose essence is a special type of loving friendship. 40
Thus Augustine "refutes in advance those who say that only in
modern times has marital intercourse been seen in relation to
conjugal love and the interpersonal relationship of spouses. " 41
Furthermore, he seems to be saying that the friendship from
which marriage and sexual intercourse draw their meaning is
integrally tied to the propagation of the human race, that is,
children. This propagation of the human race as a service to the
loving friendship of family and society can only take place within
the faithful and indissoluble union of marriage. Thus, we see
Augustine insinuating that the three goods of marriage he
delineates are in fact one triune good, distinct but inseparable
39 This is supported by the fact that in De bono coniugaliAugustine referred to the crown
of marriage as "the chastity of procreation and faithfulness in rendering the conjugal debt."
See Augustine, The Good of Marriage [De bono coniugal1],trans. T Wilcox, Fathers of the
Church 27 (Washington, D.C.: The Catholic University of America Press, 19 55), 11.12 (CSEL
41:204).
-rosee Cahall, "The Trinitarian Structure of St. Augustine's Good of Marriage," 225-29,
where I discuss the essence of marriage as loving friendship in Augustine's thought.
41 John J. Hugo, St. Augustine on Nature, Sex, and Marriage (1969; repr. Princeton, N.J.:
Scepter Publishers, 1998), 133.

PERRY]. CAHALL

354

aspects of conjugal love. If any one of these three elements is
deliberately removed, then the good that is marriage no longer
exists. The rightful delight of sexual intercourse is that which
"comes from one's love reaching out to the beloved spouse and
the hoped for child. "42
This means that there can be no conflict between a truly
upright desire for sexual intercourse and any of the three goods
of marriage. Against those who claim that Augustine saw a conflict
between love and procreation it should be noted, as John Connery
has pointed out, that for Augustine the issue was rather a conflict
between a desire for sexual pleasure and procreation. 43 Augustine
did not see the sexual impulse, sexual intercourse, or the pleasure
attendant upon sexual intercourse as being opposed to conjugal
love as long as they remain ordered to the natural end of marital
intercourse, which is children. The beginning of De bono
coniugali makes it clear that "society, springing from the primitive
friendship of man and woman, is continued in children-not just
from their association in love and friendship but from their sexual
relationship, or physical intimacy, within the context of such
friendship. "44
It must be admitted that Augustine did not write explicitly
about how marital intercourse or the pleasure associated with it
can enhance marital affection or the interpersonal communion
between spouses. However, if for Augustine the context of sexual
activity is a union typified by conjugal friendship, then logically
he would have presupposed that any use of sexual intercourse
would serve this love. His comments on restricting the excesses of
sexual desire should be seen as ways in which he saw sexuality
deviating from the fullness of love. His silence in elaborating any
further relationship between sexual intercourse and marital love
is simply silence. Furthermore, this silence is understandable
when one realizes that Augustine's comments about sexual
intercourse and sexual desire are circumscribed by his debate with
Julian of Eclanum over original sin and its effects. The issues of
42 Burt,

Friendshipand Society, 114.

"The Role of Love in Christian Marriage," 246.
Regan, "The Perennial Value of Augustine's Theology of the Goods of Marriage," 355.

43 Connery,
44

CONJUGAL LOVE AND DMNE LOVE

355

this debate did not require Augustine explicitly to address how
sexual intercourse factors into conjugal love. Regardless of this
silence, Augustine was not opposed to sexual intercourse, nor did
he preclude it from being an expression of conjugal love. With
regard to sexuality Augustine was very clear that it is a good
creation of God. 45 He also believed all fallen emotions and
passions, including sexual desire, to be good in themselves, but
maintained that these desires need to exist in a framework
ordered by love. 46 Augustine was opposed to the satisfaction of
emotions and passions in the pursuit of pleasure as an end in itself
and apart from love. 47 Such a pursuit would render the spouse an
object of use, used as a means to achieving the end of sexual
pleasure. Augustine saw that this pursuit is ultimately selfish,
shows disregard for the spouse, is opposed to love of both God
and neighbor, and as such constitutes abuse.
Augustine did not deny that love or conjugal pleasure is proper
to spouses. 48 Instead, his point is that "to love one's spouse means
to love as a human being, body and soul, the body and soul of
one's beloved. " 49 That he included love of the body in marital
friendship is evident when he says, "holy, therefore, are the
bodies of married people who remain faithful to themselves and
to the Lord. "50 The fact that Augustine was not opposed to sexual
pleasure in this body-soul love of spouses is evident when he says
et de peccato originali 2.34.39.
civitate Dei 14.10. See William S. Babcock, "Augustine and the Spirituality of
Desire," Augustinian Studies 25 (1994): 179-99, who notes that Augustine's spirituality is not
opposed to desire but is really an endeavor to foster desires that are ordered towards God and
to eradicate disordered desires that lead away from God.
47 De civitate Dei 14.21. As Robert Innes has said, "It is not desire which Augustine rejects
but only disordered forms of desire" (104).
48 Burt, "Friendship and Subordination," 102. See also Tarsicius J. van Bavel, "Fruitio,
delectatio and voluptas in Augustine," Augustinus 38 (1993): 499-510, who shows that
Augustine did not deny that sexual pleasure is proper to spouses. It is not true that "for
Augustine, amor and coitus were incompatible, since affection between spouses required
sexless marriage" (Kari B9rresen, "In Defence of Augustine: How femina is homo," in B.
Bruning, M. Lamberigts, and J. van Houtem, eds., Collectanea Augustiniana. Melanges T. ].
van Bavel, Bibliotheca Ephemeridum Theologicarum Lovaniensium 92, vol. 1 [Leuven:
Leuven University Press, 1990], 424).
49 Burt, "Friendship and Subordination," 103.
so The Good of Marriage 11.13 (CSEL 41:204).
45 De gratia Christi
46 De

356

PERRY J. CAHALL

that "pleasure is a necessary accompaniment . . . of sexual
intercourse with a view to procreation. "51 Augustine did not
forbid spouses to experience or even to enjoy sexual pleasure, as
long as this pleasure is not sought as an end in itself and as long
as the conjugal embrace is engaged in while respecting its natural
purpose. In Contra Iulianum Augustine clearly distinguishes
between bodily sensations, which are necessary and useful, and
the lustful desire for these sensations, which is sinful. 52 Earlier, in
De bono coniugali, Augustine says that the saints of the Old
Testament would have experienced a natural delight from marital
intercourse. 53 He comments on this sexual delight, saying, "For
what food is to the health of man, intercourse is to the health of
the race, and both are not without carnal pleasure, which,
however, when modified and put to its natural use with a
controlling temperance, cannot be passion [libido]."54 Commenting on this passage at the end of his life in his Retractationes,
Augustine says that he had made this statement "because the good
and right use of passion [libido] is not passion [libidinis]. For just
as it is evil to use good things in the wrong way, so it is good to
use evil things in the right way."55
According to the logic of Augustine's thought, a good and
correct use of disordered sexual passion or lust, as a desire that
tends to escape control of reason and will, would be a use that
brings it into the service of love. This use would order the desire
51 Augustine, Concerning the City of God against the Pagans, trans. Henry Bettenson
(London: Pelican Books, 1972; Penguin Books, 1987), 19.1; De civitate Dei 19.1 (CSEL 40).
sz Contra lulianum 4.14.65.
s3 De bono coniugali 16.18.
s4 The Good of Marriage 16.18 (CSEL 41:210): "Quod enim est cibus ad salutem hominis,
hoc est concubitus ad salutem generis, et utrumque non est sine delectatione camali, quae
tam en modificata et temperantia refrenante in usum naturalem redacta libido esse non po test."
A better rendering of libido would be "lust."
ss Retractations [Retractiones], trans. Mary Inez Bogan, Fathers of the Church 60
(Washington, D.C.: The Catholic University of America Press, 1968), 2.48.2 (CCL 57:108):
"Quod ideo dictum est, quoniam libido non est bonus et rectus usus libidinis. Sicut enim
malum est male uti bonis, ita bonum bene uti malis" (written around 426/27). It should be
noted that Augustine is not saying that we may do evil to bring about good. What he is saying
is that an effect of original sin or a physical evil (as opposed to a moral evil), namely our
wounded human desires, may be employed for a good end.

CONJUGAL LOVE AND DIVINE LOVE

357

for pleasure in service to the triune good of marriage, supporting
spousal friendship and the permanence of the union through the
begetting of children. This is evident in De Genesi ad litteram,
where Augustine comments on the way procreation would have
taken place in Paradise if Adam and Eve had not sinned. He states
that in the union of their bodies "there would be only the devout
affection of charity, and not the concupiscence associated with
our corrupt flesh, in the procreation of children. " 56 He asks,
Why, therefore, may we not assume that the first couple before they sinned
could have given a command to their genital organs for the purpose of
procreation as they did to the other members which the soul is accustomed to
move to perform various tasks without any trouble and without any craving for
pleasure? 57

In several other places Augustine refers to the ordered manner in
which sexual intercourse would have occurred before the Fall.58
Although the chief point of all these passages is that sexual
intercourse before the Fall would have been engaged in only for
procreation, one may safely assume that it also would have
occurred within the order of the love and friendship that
characterized the relationship of the primordial spouses.
Augustine did say that spouses who desire to have sexual
intercourse for purposes other than procreating children are in
some respect giving in to carnal concupiscence, seeking sexual
pleasure as an end in itself, and are thus committing a sin.59 This
is why he says at the beginning of De bono coniugali that children
"are the only worthy fruit, not of the joining of male and female,

56 Augustine, The Literal Meaning of Genesis [De Genesi ad litteram1 trans. John
Hammond Taylor, Ancient Christian Writers 41-42 (New York: Newman Press, 1982),
3.21.33 (CSEL 28:88).
57 Ibid., 9.10.16 (CSEL 28:279).
58 DecivitateDei14.23-24;Degratia
Cbristietdepeccato originali 2.35.40; Epistula 6•.8;
De nuptiis et concupiscentia 1.5.6; 2.22.37; Contra duas epistulas Pelagianorum 1.17.35;
Contra Iulianum 3.25.57; 4.11.57; 4.13.62; 4.14.69; Contra Iulianum opus imperfectum
1.68; 2.42.45; 4.19.
59 De bono coniugali 6.6; 10.11; De civitate Dei 19.1 (this book was written sometime
between 425 and 427); Senno 51.22 (written ca. 400).

358

PERRY J. CAHALL

but of sexual intercourse. "60 He has often been vilified for this
position because it seems to leave little room for the conjugal
embrace to contribute to the love of spouses. However, it must be
noted that because of the good that marriage is, and in particular
because of the {ides and the sacramentum of marriage, this sin of
spouses seeking pleasure in sexual intercourse is, according to
Augustine, only venial. 61 This testifies to the goodness that
Augustine saw in the married state, because "although intercourse
outside marriage is gravely sinful, within lawful marriage, even
when passions run out of control and there is no desire of
procreation, it cannot exceed venial sin. "62
Furthermore, Augustine Regan has pointed out that what Saint
Augustine meant by "venial sin" is more correctly understood as
"a moral imperfection" than as a formal sin, since he had in mind
actions that would promote the greatest growth in the perfection
of love between spouses. 63 For Augustine, a man and a woman
(who are not necessarily Christian) are truly married even if
throughout their entire married life they have intercourse
motivated by incontinence instead of for the purpose of procreation, as long as they have intercourse only with each other
and they do not avoid procreation when they have intercourse
(attempting to refuse to have children or to prevent them from
1.1(CSEL41:187-88).
6.6; 7.6; De bona viduitatis 4.5; Sermo 51.22; De nuptiis et concupiscentia
1.14.16; Contra lulianum 4.3.33; 5.16.63.
62 Hugo, St. Augustine on Nature, Sex, and M.arriage, 123.
63 Regan, "The Perennial Value of Augustine's Theology of the Goods of Marriage," 364:
"the peccatum veniale in question would these days be called a moral imperfection; at a time
when the theology of venial sin and imperfection had not been worked out, S. Augustine did
not have the terminological precision to express his thought with all exactness. Seeing the
spiritual life as a continual advance towards perfection according to the orda amoris, this
advance is slowed down when, instead of voluntary and generous abstinence, a married person
seeks the pleasure of sexual relations with a lawful partner. On the other hand, to seek such
as a means of remaining faithful cannot be really sinful. In the abstract, the more perfect
action is, by definition, better than the less perfect: in the concrete hurley-burley of daily life,
the less perfect is often the only thing the average person is capable of. To attempt more
would be presumptuous, and maybe would involve danger of lapsing into the sinful. In this
concrete situation, the less perfect is not only good, but, paradoxically, better than the more
perfect."
60 The Good of M.arriage

61 Ibid.,

CONJUGAL LOVE AND DIVINE LOVE

3S9

being born}. 64 In this case, the carnal concupiscence of the spouses
has been channeled by and serves the bond of fidelity. The presence of disordered sexual desire does not lead to a condemnation
of the sexual intercourse that results. 65 Augustine saw sexual
intercourse, even without an explicit desire for procreation, in
service to spousal fidelity, as a legitimate use of the conjugal
embrace.
Dealing with Augustine's position that it is a venial sin to
engage in sexual intercourse beyond that necessary for
procreation, David Hunter has focused on Senno 354A, written
around 403-4, shortly after Augustine wrote De bona coniugali.66
In this sermon Augustine condemns the adoption of celibacy by
one spouse without the consent of the other. Hunter highlights a
nuance of Augustine's thought on marriage, noting that Augustine
says that a spouse who renders the conjugal debt when it is
demanded by the other spouse, even if children are not sought,
performs an act of charity, mercy, and even continence in the
faithful support of his or her spouse. 67 Thus, Hunter argues that
at least in this "very limited instance" Augustine is proposing
sexual intercourse as an act of love.68 Moreover, even the spouse
who demands sexual intercourse beyond that necessary for
procreation is guilty of a sin that is a "daily sin" so slight that it
can be remitted by daily recitation of the Lord's Prayer. 69 Thus
Hunter states:
Within marriage, the inordinate enjoyment of sex (that is, sex apart from
procreation) is taken for granted as a normal (though, to Augustine's mind,
regrettable) feature of post-lapsarian life, that is, of life under the influence of
concupiscence. While Augustine clearly regards such excess as a 'sin' (peccatum)
or 'fault' (culpa), the degree of the fault, as these sermons indicate, verges on the
insignificant. 70
64

De bono coniugali S.S.

65 De nuptiis et concupiscentia 2.21.36.
66 David Hunter, "Augustine, Sermon 3S4A: Its Place in His Thought on Marriage and
Sexuality," Augustinian Studies 33, no. 1 (2002): 39-60.
67 Ibid., 47-49
68 Ibid., 49.
69 Ibid., 46.
70 Ibid., 46-47.

360

PERRY J. CAHALL

Augustine did fail to see how a couple can be acting according
to reason, without committing "venial sin," if they engage in
sexual intercourse without an explicit intention to procreate. He
distinguished, however, between a couple who willfully oppose
life by distorting an act of sexual intercourse through an evil
device or intention (i.e., contraceptive intercourse), and a couple
who may not directly intend that their act of intercourse result in
a child but nonetheless do not directly oppose the child coming to
be. 71 This second case would include couples who engage in
sexual intercourse even if circumstances beyond their control (i.e.,
intercourse during pregnancy, postmenopausal intercourse, or
intercourse during infertile days of a woman's menstrual cycle)
make it impossible for their act of sexual intercourse to result in
the conception of a child. Augustine qualified the couple in the
first case as being guilty of serious sin while the couple in the
second case are guilty of "venial sin." However, he failed to note
that while the contracepting couple act in a way that is contrary
to reason by acting in a way that is contrary to life, the other
couple acts accordingto reason, and without moral fault, because
they do nothing that is opposed to or distorts God's design for
sexual intercourse or the triune good of marriage.
Even though Augustine may be faulted for requiring an explicit
intention to procreate for the ideal use of sexual intercourse and
for not commenting more explicitly on how the conjugal act can
serve conjugal love (outside of the limited instance noted by
Hunter above), he did explicitly acknowledge the service that
sexual intercourse renders to marital fidelity. Thus he saw that
sexual intercourse and its attendant pleasure can be used in such
a way as to support and serve one aspect of spousal friendship and
love. Although he believed that the ideal use of marital
intercourse is that which is engaged in with the intention of
procreating, Augustine acknowledged that even marital
intercourse pursued out of incontinence or engaged in without
directly intending to conceive a child can support the bond of
fidelity as long as procreation is not purposefully eliminated from
71 See De nuptiis et concupiscentia

1.15 .17.

CONJUGAL LOVE AND DIVINE LOVE

361

that act by any evil device or intention. 72 Even in this less ideal
instance, sexual intercourse would be serving spousal fidelity, and
also (although not necessarily with an explicit intention) the
totality of the triune good of marriage.
I contend that everything Augustine says about the proper use
of sexual intercourse within marriage should be viewed as his
attempt to show how the conjugal embrace should serve conjugal
love. He believed that charity would have inspired sexual activity
before the Fall and he saw with great clarity that all spousal
friendship increases to the extent that postlapsarian disordered
sexual desire does not intrude into the relationship. 73 He warned
spouses about the effects this disordered desire can have on
conjugal love (caritas coniugalis).74 In fact, it was because the
marriage of Mary and Joseph was based upon a deep spiritual love
(possessing the fullness of the triune good of marriage}75 free of
carnal concupiscence, and not primarily because they abstained
from sexual intercourse, that Augustine saw their marriage as the
ideal Christian marriage,76 possessing the fullness of conjugal love

(caritas coniugalis).77
It is true that Augustine counseled total abstinence in marriage
if both spouses agreed to live out this form of chastity. 78 He gave
this counsel because he thought the "time for embracing" (Esdras
3:5) was over; 79 because he was encouraging people to embrace,
if they could, the higher calling of celibacy, which is an
eschatological sign of how all human beings will exist in eternity; 80 and because in a continent marriage all of the spouses'
72 Ibid.

Contra Iulianum 5.12; Senno 51.21 (some scholars suggest a date for this sermon
around 400 while others suggest a date around 418). On this point see also Connery, "The
Role of Love in Christian Marriage," 245-46.
74 De bono coniugali 7.6.
75 De nuptiis et concupiscentia 1.11.13.
76 Ibid., 1.11.12.
77 Senno 51.21.
78 De bono coniugali 6.6; De nuptiis et concupiscentia 1.11.12.
79 De bono coniugali 9.9; De adulterinis coniugiis 2.12.12 (written around 420); De Genesi
ad litteram 9.7.12; De nuptiis et concupiscentia 1.13.14.
80 De bono coniugali 8.8; 23.29; De sancta virginitate 1.1; 8.8; 11.11.
73

362

PERRY J. CAHALL

energies are directed toward a chaste union of souls 81 in prayer 82
that is ordered towards union with Christ. 83 Augustine was
remaining faithful to his understanding that a union of minds and
wills is more profound and intense than a physical union. He was
also remaining consistent in his understanding that the bodily
union of husband and wife is for this world alone because
marriage is a temporal institution. However, he also saw that
marital love increases to the extent that spouses are able to hold
sexual lust in check by periodically forgoing sexual relations. 84 In
fact, he states in De bono coniugali that spouses cannot learn how
to use sexual intercourse well unless they are able through
continence not to avail themselves of it. 85 Thus by counseling
continence, either permanent or periodic, Augustine was counseling spouses on how to purify and intensify their love.
There is evidence that Augustine saw the possibility of sexual
pleasure flowing from a loving union between spouses, if brought
into the "order of love" (ordo amoris) 86 according to the virtue of
marital chastity. In Senno 159, written not before 418, Augustine
classifies the pleasure derived from the marital embrace as licit
when he states: "The embraces of husbands and wives are
delightful; so too are those of harlots; the first sort lawfully, the
second unlawfully. So you see, my dearest friends, that our bodily
senses provide us with delights both lawful and unlawful. "87 Here,
even though Augustine does not describe how the pleasure of
81 De sennone Domini

in monte 1.15.42 (composed around 393-95); De bono coniugali

3.3.
82 De bono coniugali 10.11; Senno 210.9 (delivered at the beginning of Lent, but the date
is uncertain).
83 De civitate Dei 21.26 (this book was written sometime between 425 and 427).
84 Senno 51.21.
85 De bono coniugali 21.25.
86 See ibid. 3.3. For more on the "order of love" in Augustine's thought see Cahall, "The
Trinitarian Structure of St. Augustine's Good of Marriage," 231.
87 Sennon 159, trans. Edmund Hill, Works of Saint Augustine 3/5 (New York: New City
Press, 1992), 2; Senno 159.2 (PL 38:868-69). Thus it is not true, as one author has claimed,
that for Augustine "true love is possible only when the sexual element is absent" (Kari
B1uresen, Subordination and Equivalence: The Nature and Role of Women in Augustine and
Thomas Aquinas, trans. Charles H. Talbot [Washington, D.C.: University Press of America,
1981], 12).

CONJUGAL LOVE AND DIVINE LOVE

363

sexual union can enhance the loving union of the spouses, he does
explicitly sanction the experience of sexual pleasure in the lawful
embraces of husband and wife.
IV. MARRIAGE AS HEALING INSTITUTION

Ultimately, Augustine's comments on sexual desire and lawful
sexual pleasure insinuate that the spouses' sexuality should be
ordered completely towards serving procreation, fidelity, and the
sacrament, which in turn form the triune structure of the loving
friendship of marriage. This is why Augustine says that even now,
"Concupiscence is diminished in ever-increasing ardor of
charity. " 88 He saw that sexual behavior always had to be subordinated to the loving friendship that characterizes marriage. 89
It is not desire in general or sexual desire in particular that is the
problem in the spouses' realization of marital friendship. The
problem is the disorder of these desires. 90 Using sexual intercourse
to fulfill a selfish desire for pleasure poses an obstacle to spousal
friendship. 91 For Augustine, the virtue of continence, which is
involved in marital chastity, is that gift of God which allows
husbands and wives to resist the disordered impulses associated
with fallen sexual desire as well as other disordered desires. 92
Thus, God's grace always plays a part in the human struggle
against the concupiscence of the flesh. 93
According to the logic of Augustine's thought, the threefold
good concupiscence of marriage that he outlined in Epistula 6*,
which places the desire for sexual intercourse in the context of the
three goods of Christian marriage, can help spouses to overcome
the effects of disordered carnal concupiscence. In Christian
88 Against Julian 6.16.50

(PL 44:851).

89 Rist, Augustine: Ancient Thought Baptized, 197.
90 Burt, "Friendship

and Subordination in Earthly Societies," 101.

91 Ibid., Friendshipand Society, 114.

1-5 (written either around 395-96 or 418-20).
Contra lulianum 2.4.9; 3.21.49; 5.16.65;
Contra lulianum opus imperfectum 1.70. The fact that Augustine always sees God's grace as
enabling humanity to fight against carnal concupiscence is highlighted in Lamberigts, "A
Critical Evaluation of Critiques of Augustine's View of Sexuality," 185.
92 De continentia

93 Contra duas epistulas Pelagianorum 1.10.18;

PERRY J. CAHALL

364

marriage carnal concupiscence is confined to a permanent union
(the effect of the sacramentum) and can be directed towards
serving the goods of procreation (proles) and fidelity (fides), 94
according to the virtue of conjugal chastity. 95 This is what Augustine means when he says that marriage makes good use of the evil
of carnal concupiscence,9 6 or that marriage is a cure or remedy for
the vice of incontinence. 97 He saw Christian marriage as a healing
institution not primarily because it provides a legitimate outlet for
sexual concupiscence but because it offers motivation for its
control, 98 and empowers the couple in this effort. Benedict Ashley
has explained quite succinctly that when Augustine spoke of
controlling concupiscence as one of the goods of marriage,
This must be understood not merely in a negative sense, that the married need
not seek sexual satisfaction outside of marriage, but in the positive sense that the
Sacrament enables the married couple to acquire the virtue of chastity as the holy
and humanly fulfilling use of God's gift of sexuality. 99

Likewise, John Hugo has said:
The need for a "remedy for concupiscence," a phrase so offensive to modern
ears, is but an implicit acknowledgment of the effects of original sin in all the
activities of men, not a derogation of marriage. The "remedy" is itself a form of
mutual aid intended to restore conjugal love to its divinely intended purposes. 100

And we must remember that for Augustine the divinely intended
purpose of all love is a participation in divine life.
At this point I will examine what Augustine said about the
nature of love and attempt to demonstrate how he himself
94 De bono coniugali

3.3; 4.4.

De nuptiis et concupiscentia 1.3.3-4,5; Epistula 6•.5, 8; Contra Iulianum opus
imperfectum 1.68.
96 De bono coniugali 3.3; De gratia Christi et de peccato originali 2.37.42; De continentia
12.27; Epistula 6•.7; De nuptiis et concupiscentia 2.21.36; Contra Iulianum 3.20.41;
3.21.49; 3.25.57; 5.12.46; 5.16.63; Contra Iulianum opus imperfectum 1.68; Retractationes
95

2.79.
2.12.12.
Connery, "The Role of Love in Christian Marriage," 245.
99 Benedict M. Ashley, Living the Truth in Love: A Biblical Introduction to Moral Theology
(New York: Alba J:Iouse, 1996), 245.
100 Hugo, St. Augustine on Nature, Sex, and Marriage, 140.
97 De adulterinis nuptiis

98

CONJUGAL LOVE AND DIVINE LOVE

365

provides us with the tools to elaborate his theology of conjugal
love. In many respects I will be following the lead of Peter Brown,
who said:
It is the joy of Augustine scholarship precisely that it is possible to discover what
Augustine might have said, but chose not to say; and it is the urgent need of the
modern study of his thought to insist that the careful reconstruction of what
Augustine could have said, refused to say, and finally, chose to say are infinitely
to be preferred to those many attempts (by writers of all persuasions) to tell the
deeply thoughtful, but determined, old bishop of Hippo what he should have
said. 101

V. THE NATIJRE OF LOVE AS PARTICIPATION IN DIVINE LIFE

Love is a central theme in the thought of St. Augustine.
Tarsicius J. van Bavel has noted that Augustine addresses love
more often than any other theme; yet, van Bavel contends that the
theme of love is often overlooked in Augustine's anthropology. 102
This is an unfortunate oversight since for Augustine, "Love is the
profoundest thing one can say of the human being. " 103 For
Augustine, "Love alone differentiates human beings, for . . . a
person 'is' what he or she loves." 104
Augustine provided several complementary definitions of
love. 105 In De diversisquaestionibusoctaginta tribus he states that

"Augustine and Sexuality," 1.
van Bavel, "The Anthropology of Augustine," Louvain Studies 5 (1974): 44.
103 Tarsicius J. van Bavel, "Love," in Augustine through the Ages: An Encyclopedia, ed.
Allan D. Fitzgerald (Grand Rapids, Mich.: Eerdmans, 1999), 509.
UM Ibid. See In epistulam Iohannis ad Parthos tractatus 2.14 (written around 406/407).
105 Van Bavel has noted that when writing about love "Augustine does not make an
essential difference between the three Latin words amor, caritas, and dilectio. All three can be
good or evil according to the object loved" ("Love," 509). For in-depth treatments of
Augustine's theology of love see Hannalt Arendt, Love and Saint Augustine, ed. and trans.
Joanna Vecchiarelli Scott and Judith Chelius Stark (Chicago: University of Chicago Press,
1996); Gunnar Hultgren, Le commandement tlamour chez Augustin: Interpretation
philosophique et theologique tlapres /es krits de la pbiode 386-400 (Paris: Vrin, 1939);
William Riordan O'Connor, "Augustine's Philosophy of Love," (Ph.D. diss., Fordham
University, 1982); Oliver ODonovan, The Problem of Self-Love in St. Augustine (New Haven:
Yale University Press, 1980).
101 Brown,

102 Johannes

366

PERRY J. CAHALL

it is a type of motion (motus) 106 or appetite (appetitus), 107 which
"is nothing other than to desire something for its own sake. " 108
This highest virtue seeks the eternal happiness of the one loved
without expecting anything in return. 109 In De Trinitate he says:
in this question concerning the Trinity and the knowledge of God, nothing else
is to be particularly considered, except what is true love, or rather what is love.
For only true love may be called love, otherwise it is desire [cupiditas].
Therefore, it is a misuse of terms to say of those who desire that they love, just
as it is a misuse of terms to say of those who love that they desire. But this is true
love, that while holding fast to the truth, we may live justly, and therefore, may
despise everything mortal for the sake of the love of men, whereby we wish them
to live justly.110

Thus for Augustine true love always has reference to truth and
justice, it is always disinterested, and it can ultimately be
understood only with reference to God, who is Love.
Augustine therefore believed that if we are to know the
meaning of love we must look to the God who is Love.
If nothing concerning the praise of love was said in all these pages of this epistle
[ofJohn], if nothing at all through the rest of the pages of the Scriptures, and we
heard this one thing alone from the voice of God's Spirit, that 'God is love' [1
John 4:8] we ought to seek nothing more. 111

Augustine calls his readers to imitate this divine life of love in
their relations with each other. 112 In a passage of De Trinitate that
106 De diversis quaestionibus

octoginta tribus, 35.1 (written between 388 and 396).

107 Ibid., 35.2.
108 Eighty-Three Different Questions [De diversis quaestionibus octoginta tribus1 trans.
David Mosher, Fathers of the Church 70 (Washington, D.C.: The Catholic University of
America Press, 1982), 35.1 (PL 40:23).
109 In epistulam Iohannis ad Parthos tractatus, 6.4.
110 The Trinity [De Trinitate1 trans. Stephen McKenna, Fathers of the Church 45 (1963),
8.7.10 (CCL 50:284). Augustine began work on De Trinitate in 399 and completed it as late
as426.
111 Tractates on the First Epistle ofJohn [In epistulam Iohannis ad Parthos tractatus], trans.
John W. Rettig, Fathers of the Church 92 (Washington, D.C.: The Catholic University of
America Press, 1995), 7.4 (PL 35:2031).
112 See Raymond Canning, The Unity of Love for God and Neighbor in St. Augustine
(Heverlee-Leuven: Augustinian Historical Institute, 1993), 314-30; Canning responds to
scholars who claim that Augustine ignored the interpersonal nature of love.

CONJUGAL LOVE AND DIVINE LOVE

367

discusses how the Father and the Son are united through the Holy
Spirit, Augustine states:
through Him [the Holy Spirit] the begotten is loved by the begetter, and in turn
loves him who begot Him; in Him they preserve the unity of spirit through the
bond of peace [Eph. 4:3], not by a participation but by their own essence, not
by the gift of anyone superior to themselves but by their own gift. And we are
commanded by grace to imitate this unity, both in our relations with God as well
as among ourselves. 113

Thus Augustine makes an explicit appeal for his readers to imitate
the unity of the life of the Trinity, not only in their relationship
with God but also in their relationships with each other.
It is apparent then that when dealing with interpersonal love
on the human level, for Augustine a "merely human love for one
another is not sufficient." 114 He makes it clear that we cannot
truly will the good of the other, and thus love him or her with
reference to God, without God's help. The love by which
Christians, which includes Christian spouses, must love each other
and God is ultimately a participation in the life of God, through
the Person of the Holy Spirit. True love is God's love given to us
by the Holy Spirit. True love is thus an infused love, a
supernatural gift, a gift of grace. In De Trinitate Augustine states:
When God the Holy Spirit, therefore, who proceeds from God, has been given
to man, He inflames him with the love for God and his neighbor, and He
Himself is love. For man does not have whence to love God, except from God.
Wherefore a little later he says: 'Let us love him, because he first loved us' [1
John 4:7-19]. The Apostle Paul also says: 'The charity of God is poured in our
hearts by the Holy Spirit, who has been given to us' [Rom 5 :5]. 115

Augustine explicitly identifies authentic human love as being a gift
of God Himself:
Embrace love, God, and embrace God by love. It is love itself which unites all
the good angels and all the servants of God by the bond of holiness, and unites
us and them mutually with ourselves and makes us subject to Himself. Therefore,
113 The Trinity, 6.5.7 (emphasis added) (CCL 50:235).
114
115

van Bavel, "Love," 515.
The Trinity 15.17.31(CCL50A:506-7).

PERRY J. CAHALL

368

the more we are cured of the swelling of pride, the more we are full of love, and
of what, if not of God, is he full who is full of love? But one may object: "I see
love and I conceive it in my mind as best I can, and I believe the Scripture when
it says: 'God is love, and he who abides in love abides in God,' but when I see
it I do not see the Trinity in it." But as a matter of fact you do see the Trinity if
you see love.... "Beloved, let us love one another, because love is from God.
And everyone who loves is born of God and knows God. He who does not love,
does not know God, for God is Love" [lJohn 4:7-8,20]. This context shows
sufficiently and clearly that brotherly love itself (for brotherly love is that
whereby we love one another) is taught by so eminent an authority, not only to
be from God, but also to be God. 116

In a similar vein he says:
How then a little before this, 'love is of God,' and now 'love is God'? ... If ...
the Holy Spirit is God and he in whom the Holy Spirit dwells loves, therefore
love is God, but God because [it is] of God. For you have in the epistle, both
'love is of God' and 'love is God.' ... But because the Apostle says, 'The love of
God has been poured forth in our hearts by the Holy Spirit who has been given
to us' [Romans 5 :5], let us understand that in love is the Holy Spirit. 117

Augustine again makes it dear that God is present in authentic
human love when he writes, "So entirely is love or charity the gift
of God that it is even called God, as the apostle John says: Charity
is God, and whoever remains in charity remains in God, and God
in him [1 John 4:16]." 118 Thus, through "participation or
presence, the Holy Spirit is really present in human love. Our love
is not independent of God nor foreign to Him, so that God is
really present in our love. " 119 Augustine sees that Christian love
"must be inspired by divine love, and ought to mirror it. " 120 This
love, given to us as a gift of God, "excludes all that is sinful,
namely, possessive or egoistic love, pretension, self-glorification,
116

Ibid., 8.8.12 (CCL L:286-88).

117 Tractates on the First Epistle of john,

7.6 (PL 35:2031-32).

118 Sermon 156, trans. Edmund Hill, Works of Saint Augustine 3/5 (New York: New City

Press, 1992), 5; Sermo 66.5 (PL 38:852-53), written in 417.
119 Tarsicius van Bavel, "The Double Face of Love in St. Augustine: The Daring Inversion
'Love is God'," Studia Ephemeridis Augustinianum 26, Congresso Internazionale su S.
Agostino nel Centenario della Conversione, Atti 3, 69-80 (Rome: Institutum Patristicum
"Augustinianum", 1987), 78.
120 van Bavel, "Love," 514.

CONJUGAL LOVE AND DIVINE LOVE

369

and seeking one's own profit. " 121 It is a love by which we will the
ultimate good of the other, namely that he or she finds his or her
fulfillment in God.
VI. CONJUGAL LOVE AND DIVINE LOVE

What Augustine says about true love and love's origin in the
Trinity should be kept in mind when he discusses the loving
friendship between spouses. For Augustine the essence or source
of all friendship is love. 122 The love of friendship is characterized
by reciprocity, equality, benevolence, and openness, and is
founded in the truth. 123 Furthermore, where Augustine linked
friendship with love he also linked love with God: "After all, what
else is friendship? It has received its name from nothing else but
from love and is faithful nowhere but in Christ, in whom alone it
can also be everlasting and blessed. " 124 In this passage Augustine
has linked the love of friendship with Christ, who is love
incarnate. He points to the fact that true love is experienced by
being incorporated into Christ and true love should reflect the
everlasting and blessed love of Christ. 125 Elsewhere, Augustine
distinguished Christian friendship from other forms of friendship
by noting that Christian friendship is elevated and transformed by
the Holy Spirit and the embrace of God's grace through Jesus
121 Ibid., 514-15.
122 For a discussion of the evolution of Augustine's concept of friendship a good resource
is Marie A. McNamara, Friends and Friendship for Saint Augustine (New York: Alba House,
1964), 213-37. For an explanation of how Augustine's concept of friendship relates to the
classical notion see Caroline White, Christian Friendship in the Fourth Century (Cambridge:
Cambridge University Press, 1992), 185-217. A good discussion of Augustine's concept of
friendship as presented in the Confessions is John F. Monagle, "Friendship in Saint
Augustine's Biography," Augustinian Studies 2 (1971): 81-92.
123 Burt, Friendship and Society, 62-64.
124 "Answer to the Two Letters to the Pelagians" [Contra duas epistolas Pelagianorum],
trans. Roland J. Teske, in Answer to the Pelagians II, Works of Saint Augustine 1, vol. 24
(New York: New City Press, 1998), 1.1(CSEL60:424). See also Confessiones4.7.12; 4.9.14
(written between 397 and 401) where Augustine roots true friendship in the friends' mutual
love for God.
125 See James McEvoy, "Anima una et cor unum: Friendship and Spiritual Unity in
Augustine," Recherches de Theologie ancienne et mediivale 53 (1986): 80.

PERRY J. CAHALL

370

Christ. Augustine saw that the love of friends is a gift of God
poured into their hearts by the Holy Spirit. 126 In his Confessiones
Augustine says that true friendship "is not possible unless you
[God] bond together those who cleave to one another by the love
which 'is poured into our hearts by the Holy Spirit who is given
to us (Rom 5 :5).'" 127
If we apply these insights to Augustine's theology of marriage
we see that the friendship that "became for Augustine the core of
Christian marriage ... [is] a friendship further transformed by
divine charity. " 128 The logic of Augustine's thought demands this
conclusion. Christian spouses are to love each other with a love
that is a participation in the life of the Trinity. The logic of
Augustine's thought was not just proposing the Trinity as a model
for married love. According to his understanding of divine and
human love, if spouses truly love each other they are loving each
other in and through God who through the Holy Spirit elevates
their love to be able to participate in the love of the Trinity.
Augustine comes close to relating human sexuality to the divine
life of the Trinity at the end of Book VIII of De Trinitate when he
discusses the trinity he sees in love. He says:
But what is love or charity, which the divine Scripture praises and proclaims so
highly, if not the love of the good? Now love is of someone who loves, and
something is loved with love. So then there are three: the lover, the beloved, and
the love. What else is love, therefore, except a kind of life which binds or seeks
to bind some two together, namely, the lover and the beloved? And this is so
even in external and carnal love. 129

It is true that Augustine goes on to search for a trinity of love in
the "purer and clearer source" of the soul, 130 and that he
ultimately finds this image of the Trinity in the highest part of the
human person's rational soul, the mind (mens), which consists of
126 In epistulam

Iohannis ad Parthos tractatus 6.10; 10.3.

trans. Henry Chadwick, Oxford World's Classics (New York: Oxford
University Press, 1991), 4.4.7; Confessiones 4.4.7 (CCL 27:43).
128 Hugo, St. Augustine on Nature, Sex, and Marriage, 160.
129 The Trinity 8.10.14 (CCL 50:290-91).
130 Ibid., 8.10.14 (CCL 50:291).
127 Confessions,

CONJUGAL LOVE AND DIVINE LOVE

371

remembering, knowing, and loving God. 131 Nonetheless, this
trinity of love that tends toward union is apparent in external and
carnal love.
Augustine sees, even in carnal love (and one is to assume that
here he has in mind sexual intercourse), one of those traces or
vestiges of the Trinity that he says are present throughout
creation. 132 In light of what has already been said, this trace of
Trinitarian relations present in sexual intercourse would involve
the spouses seeking each other's true good. This act would serve
conjugal love by simultaneously serving all of the elements of the
triune good that constitute marriage: indissolubility, faithfulness,
and fruitfulness. This service at the very least would take the form
of not opposing or ruling out any aspect of this triune good.
Sexual intercourse at the service of conjugal love would also serve
to draw the spouses into a communion of persons that is a
temporal reflection of the eternal communion of persons of the
Trinity. 133 Not only can conjugal love be a reflection of this divine
life, it is called to participate in this life. Christian marriage is
truly a communion of persons because the principle of
communion, God the Holy Spirit, is present in the spouses' love
healing, elevating, and transforming them as they love each other,
body and soul. Augustine's thought on love and love's origin in
the Trinity is, one might say, the assumed backdrop for everything
Ibid., 14.12.15.
6.10.12. See William Riordan O'Connor, "Augustine's Philosophy of
Love," (Ph.D. diss., Fordham University, 1982): "In our earthly experience of love we take
delight in being united with another person. What we experience in such love is a finite
participation in the loving Unity that is the Triune Creator. It is a temporal anticipation of the
eternal communion we shall experience when we enjoy the vision of God together with all his
angels and saints .... Because our experience of love is a temporal anticipation of the Love
that is God, an analysis of that experience will reveal a trinity to us. For love always seeks to
unite a lover and a beloved, even in the experience of sexual love. And so there are three
components in any experience of love: the lover, the beloved, and the love itself that unites
them" (161-62). Kim Power has said that Augustine's "understanding of the evil of sexual
desire uncontrolled by the will means that there is no possibility of sexual or married love
imaging God or divine love" (Kim Power, Veiled Desire: Augustine and Women [New York:
Continuum, 1996], 161). I can agree with this statement only if the emphasis is put on
"uncontrolled by the will." If sexual desire is controlled by the will with the help of grace then
Augustine does not preclude this type of imaging.
m O'Connor, "Augustine's Philosophy of Love," 121.
131

132 De Trinitate

371

PERRY]. CAHALL

he presented regarding conjugal life. Viewing Augustine's
theology of marriage against this backdrop holds great promise,
and perhaps even provides a corrective to some of Augustine's
inadequate or incomplete statements about conjugal love while
simultaneously correcting a modern myopic view of conjugal love
that is obsessed with pleasure and individual satisfaction.
VII. CONCLUSION

Augustine saw that conjugal love is subject to many dangers in
our present fallen condition. He approached the topics of
marriage and sexuality with a profound realism that sometimes
offends modern ears. He realistically saw that the communion of
the spouses with each other is jeopardized and limited by that
carnal concupiscence of which sexual lust is a part. Carnal
concupiscence is the negative side of human passion that can
distort marital friendship-love and lead one spouse ·to use his or
her own body, or the body of the other spouse, in the selfish
pursuit of pleasure. Pleasure should accompany a total giving of
oneself to the other in an act of selfless love. Augustine saw that
carnal concupiscence presents the danger of seeking pleasure
without regard for the other. While he said little about how the
conjugal embrace or its attendant pleasure can enhance the love
of spouses, he provided the tools for allowing us to develop his
thought in this arena. If one understands and applies what
Augustine said about the nature and origin of love to his thought
on marriage, then for Augustine conjugal love and the conjugal
embrace should reflect and participate in divine love. It is clear
that he saw that the friendship-love shared by human spouses
must be totally selfless, seeking the complete and ultimate good of
the other. Therefore, Augustine himself provided the material in
his writings to allow us to see that the participation of human
spousal love in the love of the Trinity must involve a total giving
of self and must apply to all aspects of spousal life. If Augustine's
comments on sexuality and conjugal love are seen in the broader
context of his thought on the nature of love, and his

CONJUGAL LOVE AND DIVINE LOVE

373

understanding of love as participation in divine life, then his
writings lead his readers to see that with the help of God's grace
conjugal love, as it is enacted in all aspects of married life,
including the conjugal embrace, has the opportunity to reflect and
participate in the communion of love that is the divine life of the
Trinity.

The Thomist 68 (2004): 375-429

ARISTOTLE'S AETHER AND CONTEMPORARY SCIENCE
CHRISTOPHERA. DECAEN
Thomas Aquinas College
Santa Paula, CA

P

ROPONENTS OF THE perennial philosophy tend to be
embarrassed by its natural science, and this is, to some
extent, understandable. That the progress of the sciences in
the past four hundred years coincided with a widespread
repudiation of Aristotle's philosophy in general, and his natural
philosophy in particular, is not coincidental. As the natural
philosophers of the 1600s looked at nature more and more
closely, evidence began to accumulate that much of what Aristotle
thought was true about nature was not. Perhaps, many suspected,
none of it was true.
The most obvious instance of this challenging of Aristotelian
natural philosophy came from the Copernican revolution, in
which the Earth was elevated from the status of an immobile lump
of dross at the center or bottom of the universe to that of
"planet," one of the heavenly bodies orbiting the immobile sun. 1
Our promotion seemed to fly in the face of Aristotle's now
frequently derided bifurcation of nature into two regions, the
celestial and the terrestrial (or more accurately, the supra- and
1 It is often repeated that the Copernican revolution was a demotion for the Earth and for
mankind in general, taking him from the center of the universe, a privileged place in
contemporary speech, and placing him in a position of subordination and subservience. Now
man would realize, the story goes, his own insignificance in the great scheme of things. (I
doubt I need to cite evidence of this claim; examples are legion.) Regardless of whether some
may have derived an overly anthropocentric world view from the centrality of the Earth,
Aristotle did not. He consistently argued that the part of the cosmos beneath the moon was
the least both in quantity and quality. See, for example, Meteor., 2.1.353a35-b6.

375

376

CHRISTOPHERA. DECAEN

sublunary), each corresponding to two radically different kinds of
matter: aether and the familiar Empedoclean elements. If the
Earth is just another one the planets, and the planets and the other
stars are the only sensible evidence of Aristotle's aethereal
substance, then the case for positing aether weakens; the planets,
or "wandering stars, " 2 are no more aethereal than is the ordinary
kind of matter with which we are intimately familiar.
That was the beginning of the end for Aristotle's incorruptible
aether. Although the notion that an aether was still needed as a
medium for conveying gravitational and electromagnetic forces
would occasionally surface, by the end of the nineteenth century
the view prevailing among experimental scientists was that aether
was superfluous. Modern-day Thomists and disciples of Aristotle
were forced to choose between clinging to doctrines against which
the entire scientific community was arrayed, and admitting that
their masters were egregiously mistaken in a large part of their
philosophy. That many have taken the latter path, trying to
ameliorate the situation by claiming that Aristotle's natural
philosophy is not foundational for his metaphysics or ethics, or by
insisting that St. Thomas Aquinas's philosophy, unlike that of
Aristotle, is essentially metaphysical or theological, is well known.
This essay, however, will, in a manner of speaking, take the
former path, arguing that while experimental science has indeed
made a definitive case against certain particularities of Aristotle's
aether, the existence of some kind of aether, one not entirely
unlike his celestial matter, has not yet been refuted. Indeed, a
positive case can be made in favor of it still, a case based upon
recent developments within experimental science itself. In short,
we will argue that there was a real insight driving the
Philosopher's claim that to explain the cosmos more is needed
than just the sort of matter that we can touch and grip in our

2 Setting aside the presence or absence of twinkling, to the naked eye a planet looks no
different from a star, and hence a planet was thought to be one of the stars, distinguished from
the others only because its circular motion had certain irregularities, earning for it the name
planiftes, "wanderer." Likewise, then, if the Earth is one in kind with the planets, it seems
likely that it is one in kind with the stars in general.

AETHER AND CONTEMPORARY SCIENCE

377

hands, an insight of which contemporary physicists and philosophers of nature are beginning to catch a glimpse.
In order to appreciate both the degree to which Aristotle's
aether has been rejected and the degree to which it has been
resuscitated and modified by recent physics, this paper will be
divided into three parts. We will first examine the nature and
properties of Aristotle's aether, summarizing what arguments lead
him to posit its existence, and evaluating the strength of these
arguments, both in themselves and according to Aristotle.
However, because the Copernican revolution was only an implicit
attack on aether, while the most direct and successful challenge to
it (via a modern stand-in, the lurniniferous aether of electromagnetism) was the Michelson-Morley experiment of 18 8 7, in the
second part we will briefly recount the fate of aether in the hands
of early modern natural philosophers, and its rejection as a result
of this experiment and Einstein's special theory of relativity.
Lastly, we will focus on the twentieth century's gradual recognition of a critical need for aether in explaining both the very
small-in the so-called vacuum of quantum electrodynamics-and
the very large-in the curved space-time of the general theory of
relativity and astrophysics's recent postulation of a cosmological
constant.
I. ARISTOTLE'S CELESTIALSUBSTANCE
A) The Need for a New Kind of Matter
In the first book of De Caelo, his only extended discussion and
defense of aether as such, Aristotle offers what might be
characterized as four or five different arguments for aether's
existence, concluding with
Thus reasoning from all of these things, we come to believe that there is
something besides the bodies nearby and around us, something other than and

378

CHRISTOPHER A. DECAEN

separate from them, something having a more honorable nature to the degree
that it is distant from the world at hand. 3

Rather than expound each argument in detail, we will present an
overview of the reasoning as Aristotle's attempt to explain certain
observed facts about the heavens, facts that modern man is so
habituated to explaining away that he finds it difficult even to
notice their peculiarity.
Although Aristotle invokes premises about the perfection,
simplicity, and priority of certain kinds of local motion, the
principal datum of nature that he wishes to explain with aether
can be experienced firsthand by spending the night under the stars
and watching their motion as the night hours pass. One finds
himself at the center of a perfectly circular pilgrimage of stars
traveling from east to west, as though each of the heavenly bodies
were embedded on a dark orb revolving around the Earth. This
nightly, and a related yearly, uniform circular motion of the stars
should provoke a question: Why should this apparently natural
motion occur in the sky, indeed in most of the cosmos, 4 but not
here below, where few things seem to move in circles without
being coerced? This peculiarity is all the more striking when one
notices that these same heavenly bodies and their motions are
never seen to change, much less corrupt or cease-perhaps the
reason why, Aristotle suggests, the heavenly matter was named
aether, from aei thein, "always running. "5 This appearance of
3 De Caelo, 1.2.269b14-17. (All translations of Aristotle and St. Thomas will be my own.)
After some preliminary distinctions in the previous chapter, Aristotle presents the core of his
argument for aether in 269a2-269b17. St. Thomas, in his exposition of this chapter, divides
these arguments into five (I De Caelo, lect. 4), but notes that they may all be treated as one
primary argument complemented by defenses of certain key premises and responses to natural
objections; see ibid., nn. 15 and 17.
4 In spite of the caricature one often sees of the ancient and medieval idea of the cosmos,
Aristotle and all the ancient astronomers knew that the Earth and its atmosphere must be of
an insignificant size relative to the cosmos as a whole. See Aristotle, De Caelo, 2.14.297b24298a21; St. Thomas, I De Caelo, lect. 28, nn. 3-4; Ptolemy, Almagest 1.6.
5 See Aristotle, De Caelo, 13.270b16-24. Aristotle may be deriving this etymology from
Plato's Cratylus; 410b, where Socrates tells Hermogenes that "'Aether' [al9qp] I would
interpret as 'the always running' [&I 9eqp]; this may be correctly said, because this element
is always running in a flux around the air." Plato, however, is implicitly identifying aether with

AETHERAND CONTEMPORARYSCIENCE

379

eternity and incorruptibility is strengthened by the astronomical
records Aristotle has at his disposal: "For in all time gone by,
according to all records handed on from one [generation] to the
next, no change has ever appeared either in the whole of the
containing heaven or in any proper part of it. "6 To assume that a
radical difference between natural motions in the terrestrial
region and those in the heavenly does not derive from a radical
difference in the natures of the bodies in these regions appears
foolish.
Besides clarifying the aether doctrine, however, this line of
reasoning also suggests its weaknesses, especially for the modern
reader. Perhaps, one could suggest to Aristotle, the Philosopher
has not observed the heavenly motion long enough to make the
judgment that it is moving uniformly and is incorruptible; perhaps
such perfect circular motion could be accomplished by ordinary
matter by way of various combinations of rectilinear motions;
and, most importantly, perhaps it is the Earth itself rather than
the heavens that has the daily rotation and yearly orbit. 7 While
Aristotle is often accused of being insufficiently empirical in his

the sphere of fire surrounding that of air; Aristotle was the first to use the word as designating
a kind of matter that is not found below the sphere of the moon. Aristotle notes that
Anaxagoras and Empedocles applied the word to fire or air (De Caelo, 1.3.270b24-25;
2.13.294a25-27).
'De Caelo, 1.3.270b12-17. While it is unclear how many centuries of records Aristotle
personally knew to show that stars do not come to be or cease to be, at his time the Egyptians
and Babylonians were well known to have over a thousand years of accurate astronomical
records that indicate no change in the relative positions, speeds, and number of the heavenly
bodies. See D.R. Dicks, :Early GreekAstronomy to Aristotle, ed. H. H. Scullard (Ithaca, N.Y.:
Cornell University Press, 1970), 166-75.
7 Emphasizing the dialectical character of these arguments for aether, St. Thomas notes
that although all the evidence suggests that the heavenly bodies and their motions are
incorruptible, it remains a possibility that we have not observed them long enough (I De
Caelo, lect. 7, nn. 5-6). Aristotle himself does not try to show that the Earth is immobile at
the center of the universe until De Caelo, 2.13-14, and St. Thomas points out that until this
issue is settled it is possible that the Earth, not the heavens, is moving (II De Caelo, lect. 11,
n. 2). While Aristotle could not be accused of circular reasoning here, since the later
arguments against the Earth's mobility do not appear to rest on the assumption that the
heaven is a different kind of matter, nevertheless these arguments are not demonstrative.

380

CHRISTOPHER A. DECAEN

study of nature, perhaps here just the opposite is the case; perhaps
he is relying too much on (mere) appearances. 8
With this in mind it is worth recalling what kind of certitude
Aristotle claims to be offering here. Unlike the core arguments
and principles in the more foundational Physics, the arguments in
De Caelo are consistently and explicitly characterized by Aristotle
as tentative and merely probable. 9 For example, in asking why the
heavens rotate from east to west rather than the opposite, he
pauses:
Now, it may be objected that to try to explain everything without distinction
appears to be a sign either of excessive foolishness or of excessive zeal. But this
criticism is not always equally just. Rather, one must see what cause there is for
saying something, and further, what sort of belief in it one may have, whether
it be [merely] human or something more unassailable. Thus, although if someone
ever chances upon more strictly necessary [accounts], one must be grateful to
him; nevertheless for now one must state how things appear. 10

Sometimes we must be satisfied with a "consistent account that
merely harmonizes with our suspicions," restraining these suspicions so that "the appearances are always lorded over by sense. " 11
Aristotle likewise implies, when he summarizes the conclusions
reached about aether's nature in the first book, that the case for
the heavenly substance in particular, while assumed throughout
most of De Caelo, is also tenuous: "Taking belief from the things
said, [we must say] that the entire heaven was not generated nor
can it be destroyed (as some say), and that it is one and eternal. " 12
Similar language of belief, or tentative conviction, is present in the
passage quoted at the beginning of this section, when Aristotle
concludes the arguments for aether by saying that we have reason
8 As one commentator puts it, "If ever an empirical attempt was made to save the
phenomena, it is to be found in the De Caelo. In no other Aristotelian writing is it more true
that the 'mistakes' come from this implicit reliance on what 'we see' as beyond question"
Uohn H. Randall, Aristotle [New York: Columbia University Press, 1960], 153).
9 See, for example, De Caelo, 1.7.274a30-34;
1.8.277a9-13; 2.12.291b24-28;
2.13.294b30-295a2; and 3.1.299al-6.
10 De Caelo, 2.5.287b29-288a2.
11 De Caelo, 2.1.284b4-5, and 3.7.306a17, respectively; see also 2.13.293a25-30.
12 De Caelo, 2.1.283b26-28.

AETHER AND CONTEMPORARY SCIENCE

381

"to believe that there is something besides the bodies nearby and
around us. " 13 Aristotle refuses to characterize the case for aether
as a strict demonstration, leaving open the possibility that his
reader has not been convinced and may simply have to assume or
hypothesize the existence qf aether to understand the rest of the
work. He explains this ambiguity in the same discussion, before
noting the aforementioned astronomical records, when he says
that the immutability of the heavenly substance "follows from the
senses, at least sufficiently to speak on behalf of human belief
[npo <; dv0pwlTlVT]VlTlOTlV]." 14
Hence, even with an imperfect foundation, Aristotle
encourages us to strive to understand the nature of the heavenly
bodies as best we can, given the intrinsic desirability of the subject
matter:
It is good to inquire about these things and so to deepen our understanding,
although we have little to go on and we are situated at such a great distance from
the attributes of these things. Nevertheless, from contemplating such things
nothing [we infer] should seem to be unreasonable, holding them now as fraught
with difficulties. 15

Here Aristotle points out the reason that we are restricted to mere
"human belief" when we try to discern the nature of the heavens:
Like detectives without witnesses, we have little to go on. He
elucidates this later when he says, "We are far away from the
things we are trying to inquire into, far away not only in place but
more so in that we have sensation of exceedingly few of their
accidents. " 16 We sense little to nothing of the heavens; with the
exception of the luminous stars and planets, we perceive none of
the properly sensible attributes (e.g., color, smell, and sound) in
aether, but only some of the common ones (e.g., magnitude and
motion), which latter are in fact difficult to detect without the
De Cael-0, 1.2.269b14; see also 1.3.269b18-20, and 270b4.
Ibid., 1.3.270b13.
15 Ibid., 2.12.292al 4-18. A parallel text and locus classicusis at De PartibusAnimalium,
1.5.644b23-645a7.
16 De Caelo, 2.3.286a5-7. See also De Anima, 1.1.402b22-25.
13

14

382

CHRISTOPHER A. DECAEN

former. 17 Nor is this limitation simply in the acuity of our sense
powers; by definition aether, an invisible, incorruptible body, has
little in common with ordinary matter. As will be shown below,
it cannot be acted upon by ordinary matter and can act on
ordinary matter and our senses only indirectly or in a hidden way.
Thus, aether's hypothesized nature must be detectable via
argument, not through mere experience.
This leads us to an implicit, and in fact more certain, reason
Aristotle thinks that the four elements are insufficient to explain
the heavens. In writing De Caelo, Aristotle assumes that the reader
understands and accepts his arguments from the fourth book of
the Physics,18 namely, that a void, a region not filled by a material
substance, is not physically possible.19 After a careful consideration of what place is and what void would have to be, Aristotle
sets out a number of arguments, some merely dialectical and
others more decisive, 20 to show that it is impossible that there be
proper and common sensibles, see De Anima, 2.6; on the
visibility of the transparent, and therefore of its magnitude, via the colored bodies bounding
it, see ibid., 2.7.418b3-15.
18 Physics,4.1-9; while only chapters 6-9 treat void directly, the previous chapters on place
and the Platonic idea of space are crucial for fully appreciating the arguments in the later
chapters.
19 While there is some controversy about the chronological order of some of Aristotle's
works, there is broad scholarly agreement that the traditional pedagogical order of Physicsbefore-De Caelo is correct; see Werner ]aeger,Aristotle:Fundamentalsof the History of His
Development, trans. Richard Robinson (Oxford: Clarendon Press, 1934), 294-306. Not only
are there numerous references in De Caelo to matters settled already in Physics, but not vice
versa (e.g., 272a30, 274a19-23, 275b22, 299a10); some such references are even to Physics
4 (e.g., 303a22). At any rate, many De Caelo passages indicate that Aristotle is assuming the
refutation of void as an underlying principle in the aether doctrine. For example, just before
making the case for aether's existence in De Caelo, 1.2, he argues that there are only three
dimensions by invoking as a premise that every three-dimensional continuum is a material
body (268a1-10), something that can be assumed only if the possibility of void (a nonmaterial
three-dimensional magnitude) has been implicitly rejected already. Further, after discussing
aether's properties, he denies off-handedly the possibility there is a void outside the cosmos,
treating the question as though it had already been settled (279a11); see also ibid., 2.4.287a712, and 2.8.290a7, where he explicitly assumes that there are no empty spaces or
discontinuities in the cosmos.
20 Making this distinction is of course critical, as many commentators will take as the
fundamental argument against void what is really just a preparatory dialectical argument, and
will therefore ridicule the weakness of Aristotle's position. The problematic arguments about
motion in a void, for example, are frequently taken to be either Aristotle's primary reasons
17 On the distinction between

AETHER AND CONTEMPORARY SCIENCE

383

a place or quantity without a subject or material in which to
inhere. Thus any region that appears empty must not be so.
Looking to the heavens, then, we conclude that the vast expanse
between the visible heavenly bodies and the world in which we
live, the region that the life-giving light of the sun must traverse
to allow animals to see and plants to grow, must itself be filled
with an invisible or, better, a transparent medium. Not only are
the stars and planets made of a different kind of substance,
but-given that such perfect transparency is present in something
that manifests no signs of ordinary matter's downward or upward
tendency, but either is perfectly yielding to the visible circular
motion of the stars and planets, or moves with them-so must be
the subtle matter surrounding them. Thus, Aristotle applies the
name "aether," or more frequently, "the first body, " 21 to whatever
fills the volume of space between the moon and the outermost
sphere of the fixed stars. It is itself "the heaven ... the continuous
body in the place after the outermost circumference of the whole,
for rejecting void or his only ones; see Randall, Aristotle, 127, and Friedrich Solmsen,
Aristotle's System of the World: A Comparison with His Predecessors(Ithaca, N.Y.: Cornell
University Press, 1960), 136-41. A careful survey of Physics, 4.8 manifests that some of the
arguments pertain to motion in void, and others to void as such (the division occurring at
216a26), as most commentators will agree (e.g., Edward Hussey, in Physics, Books ill and N,
trans. Edward Hussey [Oxford: Oxford University Press, 1993], xxxv, 133; David Furley, The
Greek Cosmologists, vol. 1, The Formation of the Atomic Theory and Its Early Critics
[Cambridge: Cambridge University Press, 1987], 190-91).
21 Other than De Caelo, 1.3.270b22, nowhere else in De Caelo, Physics, or Metaphysics
does Aristotle unambiguously use the word al9Tjp to describe the heavenly substance, usually
preferring the names "first body" (ibid., 1.3.270b2-3), or "divine body" (ibid., 2.3.286all12), or generically "the heaven" (ibid., 1.9.278bll-18). Occasionally he does name it from
its circular motion (ibid., 1.3.269b29-30), or from its immutability (De Anima, 2.6.418b9).
From Aristotle's medieval disciples we received the name quinta essentia, "fifth essence," the
root of our modem words "quintessence" and "quintessential" (which will turn up in a
surprising context later in this essay).This is of course the origin of the commonly heard claim
that Aristotle posits a "fifth element." While he does call it the "first element" on one occasion
(Meteor., 1.3.340b12), he avoids calling it an element and never calls it the fifth element,
perhaps because "element" designates only what enters into composition with other things,
and because counting it as the fifth implies too much homogeneity between it and the
traditional other four; calling it "first," however, follows the order of nature, whereas calling
it "fifth" follows the order of coming to know. For better or for worse, however, Aristotle's
first body is now referred to as aether, and it was under this appellation that it was later
rejected and then more recently revised and rejuvenated. We too will follow the convention.

384

CHRISTOPHER A. DECAEN

in which are the moon, and the sun, and some of the stars [i.e.,
the planets]. " 22 Likewise this is the body whose existence Aristotle
is trying to make probable in the opening chapters of De Caelo.23
While an adequate defense of Aristotle's critique of void would
take us somewhat afield, 24 it is crucial at least to notice that this
critique is not merely the scaffolding but more the infrastructure
of the general case for aether. The heavens appear to be empty,
yet we may offer compelling arguments that such an emptiness is
physically impossible. Thus there should be a prima facie case in
favor of an essentially insensible substance that pervades apparent
voids, an aether. In the modern context this manner of interpreting De Caelo 1.2 is all the more noteworthy, for since
Aristotle's time we have taken a closer look at the heavens, and in
the past half century we have literally gotten within arm's reach
of the hypothetical aether. Nonetheless, the implicit results are
the same now as they were when Aristotle looked up at the night
sky: We lack evidence of any tangible matter, besides stars and
space dust, filling outer space.

22 De Caelo, 1.9.278b16-18. Aristotle here notes two other uses of the word ouranos,
"heaven," one more general and one more restrictive, saying that "heaven" is also used to
name the universe as a whole and also the outermost sphere of the fixed stars (278b11-21).
The one we have quoted, however, seems Aristotle's preferred. use.
23 ff it were only the stars and planets in which Aristotle was interested, the argument for
their existence would of course be quite simple: Look up. Aristotle, however, argues in a
philosophical mode in De Caelo, 1.2, presenting multiple reasons, all based indirectly on the
experience of the heavenly motion, but none simply reducible to that experience. At any rate,
the nature of the stars and planets is not taken up until 2.7, where he argues from the nature
of the heavenly substance in general to that of the stars, for "the most reasonable and fitting
account for us [to offer] is that each of the stars is made from that sort of body in which
happens its habitual motion, since we have said that there is something naturally apt to moving
in a circle" (289a14-16). This implies that in the earlier treatment of aether in 1.2ff. Aristotle
does not yet distinguish between stellar/planetary aether and the aether of the entire heavenly
region.
24 For a compelling exposition and defense of Aristotle's arguments against the void, see
St. Thomas, IV Phys., leers. 1-14. For recent critiques of the notion of void underlying the
Newtonian idea of absolute space, see R. Glen Coughlin, "Immobility of Place in Aristotle,"
PhilosophiaPerennis 1 (1994): 3-34; idem, "Some Considerations on Aristotelian Place and
Newtonian Space," Aquinas Review 1 (1994): 1-48.

AETHER AND CONTEMPORARY SCIENCE

385

B) The Properties and Nature of Aether

Although Aristotle admits that there is little we can sense about
aether, from the arguments for its existence he finds that he can
infer certain properties of it that emphasize how different it is
from ordinary matter. In order better to assess its likeness with
and difference from recent physics's version of aether, then, it will
be helpful to sharpen our image of Aristotle's aether by summarizing some of its distinctive marks and how Aristotle is driven
to them.
Since the heavenly substance is first apparent to us in virtue of
its enduring circular motion, Aristotle immediately deduces three
properties of the aether, two pertaining to its motion, and one
pertaining to its endurance. 25 Because we clearly see that the
heavens have a perpetual, and therefore probably natural, circular
motion, and not an upward or downward rectilinear motion, we
may take as corollaries that celestial matter is simple, that is, not
a compound of elements, and that it is neither heavy nor light.
Given that the circle is the simplest possible shape and that the
path of this motion is perfectly circular, it seems that it would be
effected by only one internal principle or cause, that is, by only
one elementary nature; so, aether must be simple. 26 Likewise,
defining heaviness and levity as natural inclinations toward or
away from the center of the Earth, and seeing signs only of a
natural inclination to rotate around the center, it seems "impossible that the body being borne in a circle has heaviness or
levity. " 27
Aristotle infers a third mark of aether when he says, "Likewise,
then, with good reason we may posit concerning [the heavenly
25 See De Caelo, 1.3-4.
26 The simplicity of aether is most explicitly defended in the course of manifesting aether's
existence in 1.2, e.g., at 269a2-7, 269a18-28. On the perfection of circles relative to straight
lines, see De Caelo, 1.2.269a19-25.
27 De Caelo, 1.3.269b31. At 269b32-270a5 Aristotle bolsters this conclusion by noting that
every nature is inclined only toward one place, and
toward one kind of motion to
that place, and adds that it does not even appear possible that aether could be forced to move
upward or downward. The reason for this will become dear shortly in discussing aether's
intangibility.

386

CHRISTOPHER A. DECAEN

substance] that it is ungenerable and incorruptible, and that it is
not capable of growth or alteration." 28 Although aether is
evidently subject to change in place, it is not subject to changes in
substance, quantity, or quality. Whatever undergoes a substantial
change, Aristotle points out, does so because it is acted upon by
a body with a contrary nature, while aether, whose only positive
formal attribute noted so far is its circular motion, has no
contrary, since circular motion has no contrary. 29 For the same
reason, since growth always involves substantial change between
opposites, change in the size of aether is not possible; and since
alteration is ordered toward substantial change and involves
expansion or contraction, "then just as the body with circular
[motion] is not capable of growth or diminution, it is quite
reasonable also [to say] it is inalterable. "30 With a reminder that
this depends on whether "one has trust in those things laid down
before," Aristotle reinforces the conclusion that the aether is
immutable by saying, "the account, it seems, bears witness to the
appearances and the appearances to the account." 31 He notes that
all men have thought the heavens divine, and therefore immortal,
and have even named the heavens with its eternity in mind, calling
it (as we said before) the aei thein, "the always running." Perhaps
most compellingly, Aristotle emphasizes in a passage quoted
earlier that in the extensive and precise Babylonian, Persian, and
Greek records of the positions and risings of the various
constellations, no star has been observed to deviate from its

Ibid., 270a14-15.
Ibid., 270al5-33. Defending the claim that there is no motion contrary to circular
motion is Aristotle's sole objective in De Caelo, 1.4; it is easy to see when the simple motions
are defined as toward the center or centripetal, away from the center or centrifugal, and
around the center or orbiting. For what is the opposite of an orbit? One might think of
circular motions in opposite directions-clockwise vs. counter-clockwise-as contraries, but
such directions are not really opposed. For what is clockwise when viewed from above is
counterclockwise when viewed from below, and since "above" and "below" taken this way
have no absolute significance (whether in a geocentric or in a heliocentric cosmos), any
opposition or contrariety based on them would be merely subjective.
30 Ibid., 270a34-35.
31 Ibid., 270b4-5.
28
29

AETHER AND CONTEMPORARYSCIENCE

387

ordinary motion, to slow down or speed up, much less simply to
go out or come into existence. 32
Besides going on to argue that the heavens are finite in
extension and that the incorruptibility of the aether is part of
what makes possible the eternity of the cosmos as a whole,33 this
is all Aristotle concludes about the matter of the heavens in the
first book of De Caelo. However, from these few properties of the
aether-although they are almost entirely negative (i.e., what
aether is not) 34-in other contexts Aristotle and his disciples, most
notably St. Thomas, 35 infer more corollary attributes of this new
matter. Insofar as they shed further light on this almost
inscrutable substance, we will briefly enumerate and explain them.
If aether is incorruptible two conclusions follow right away,
one pertaining to its substantial principles and the other
pertaining to its qualities. First, aether's prime matter and
substantial form must be so perfectly united that the latter must
actualize and thereby exhaust the potency of the former, insofar
as an incorruptible body by definition must lack the potential to
become anything else; aether must possess a "certain total and
universal perfection" that thoroughly fulfills its potency for
existence. 36 Indeed, if one were not to distinguish fulfilled and
32 Ibid., 270b5-26. Likewise, although the planets, or "wandering stars," do appear to
admit of changes in speed and direction, these phenomena are easily accounted for in terms
of combinations of regular circular motions.
33 Ibid., 1.5-7, 10-12. Although Aristotle has already determined in Physics, 3.5-6, that the
universe is finite, at that point he had not yet shown that there is any matter besides what is
composed of the four elements; thus, because some of the arguments there are based on the
nature of the four known elements, Aristotle returns to the question here to see if the exotic
nature of aether changes the conclusion. See St. Thomas, ill Phys., lect. 8, nn. 5-9.
34 St. Thomas points out that our knowledge of the nature of the heavenly bodies, like our
knowledge of God and of anything whose existence we must prove, must be principally if not
entirely negative; see STh l, q. 88, a. 2, ad2.
35 While some tend to see in St. Thomas a radical divergence from his teacher on some
matters, there is no evidence of this in the case of the celestial substance. Not only is St.
Thomas's exposition of Aristotle's arguments for aether and its properties (I De Caelo, lects.
4-8) among the longest lectiones in the work, it is packed with nearly thirty additional
objections to the doctrine (many coming from Philoponus) and St. Thomas's rebuttals of
them. Clearly the Angelic Doctor is committed to defending, and sometimes even elaborating,
the notion of aether.
36 St. Thomas, I De Caelo, lect. 6, n. 6; see also STh l, q. 55, aa. 1 and 2.

388

CHRISTOPHER A. DECAEN

unfulfilled potencies, one might be tempted to say that the
heavenly substance has no prime matter. More accurately,
however, one should conclude that, unlike sublunary composites,
aether's prime matter is always perfectly fulfilled, so it is
inseparable from its form, and in this sense is not really distinct
from it. Likewise, since its prime matter would not be a principle
of aether's coming to be, but only of its being, it would not be the
same sort of prime matter that is a principle of mundane
substances (which is a principle both of coming to be and of
being); it would be called prime matter only analogously. 37
Further, anything that cannot be destroyed or even altered
qualitatively must somehow be intangible. Aether must lack and
not be susceptible to the action of the tangible qualities of
temperature and pressure. If aether were cool, for instance, then
it could be heated up by the immediate contact of a hot body, and
likewise pressure exerted upon it by any contiguous sublunary
body over time would incline it toward destruction, or at

37 See Aristotle, Metaphys., 8.1.1042b2-8; 8.4.1044b3-8; 12.2.1069b24-27. Thus St.
Thomas will say that when "Averroes denies that the celestial body has matter ..•• if he
widerstands that the celestial body does not have matter insofar as 'matter' is said in the order
to motion or change, he speaks truly .••. But if he widerstands the celestial body in no mode
to have matter or some sort of subject, then he manifestly speaks falsely" (I De Caelo, lect. 6,
n. 6, emphasis added). As St. Thomas explains elsewhere, "it must be admitted that the
[prime] matter of the celestial body, considered according to itself, is not in potency except
to the form that it has .... Whence that form so perfects that matter that in no mode does
there remain in ita potency toward being [esse], but only toward where [ub1], as Aristotle says.
And thus there is not the same matter of the celestial body and of the elements except
according to analogy, insofar as they agree in the notion of potency" (STh I, q. 66, a. 2).
When he says there is no potency toward being he of course means no unfulfilled or deprived
potency; the aethereal form perfects the matter, it does not destroy it. Prime matter is still
present as a principle in aether because aether is not itself a subsistent form and it retains a
potency or ordering toward its substantial form (see De sub. sep., cap. 8, 1 86); however, its
potency is exhausted by this form, thereby removing all privation from it. Thus, its matter and
its form cannot exist apart from each other, and the physicist, who comes to the notion of
prime matter through an analysis of substantial change and the real separation of the
principles, would not even be inclined to say that there is a distinction between the principles
in aether. However, the metaphysician, whose interest is being as such, would make a
resolution of the heavenly substance revealing prime matter and form as really distinct
principles even in aether-albeit form and matter in an equivocal sense when compared to
those of mwidane substances.

AETHER AND CONTEMPORARY SCIENCE

389

minimum would alter it in some measure. 38 Both of these results
are impossible if the celestial body is wholly immutable, and thus
elsewhere Aristotle emphasizes that wherever there is no shared
matter there cannot be mutual agency.39 But if aether cannot be
pressed upon by ordinary matter, then if some body were to try
to press upon it, that body would cut right through the aether
unhindered; even more than the ever-present yet barely noticeable
medium of air through which we walk and run, the aether would
yield and be cleft without any resistance. Paradoxically put, being
wholly impervious to alteration entails that aether be perfectly
pervious to something trying to press upon it. 40
These properties remain largely negative. There is a related,
more positive avenue for detecting distinctive marks of aether.
Besides its circular motion, one other aspect of aether might
38 Aristotle notes elsewhere (e.g., De Gen. et Cor., 1.5.320b18-21) that pressure results in
heating, and so again the aether would have a degree of heat in it.
39 See De Gen. et Cor., 1.6.322b13-21; 1.10.328a18-24.
4-0 Aristotle speaks of the intangibility or subtlety of aether only occasionally and in passing
(e.g., De Caelo, 2.4.287b15-22; 4.4.382a7-21; 4.5.382a14-28), for the obvious reason that
the thought-experiment of someone pushing on the heavens is imaginable to him only per
impossibile. {On the other hand, Aristotle may be entertaining the possibility of sublunary
matter somehow violently being pushed over the boundary into the lower part of the aethereal
region when he speculates that the region near the orb of the moon may be filled with impure
aether; see Meteor., 1.3.340b6-14.) He does, however, present a simple argument that aether
is perfectly yielding when he says that if aether resisted terrestrial bodies, their motion against
each other would produce a tremendous sound, which is not observed; see De Caelo, 2.9. At
any rate, St. Thomas rightly sees that this subtlety and intangibility follows from what Aristotle
has said, and so dwells upon it more frequently; see IV Phys., lect. 12, nn. 8, 13; I De Caelo,
lect. 8, n. 15; II De Caelo, lect. 10, n. 13; ill DeAnima, lect. 17, n. 13; STh III, q. 54, a. 2,
ad 2. Note also that it is tempting to confuse the nonresisting or yielding character of a
substance with an allowance for interpenetration. They are not the same thing. Saint Thomas
grants the former in the case of the aether, but rejects the latter {except by way of a miracle;
cf. STh suppl., q. 83, aa. 1-4). One must recall that for one body to move another out of its
way does not necessarily imply that the latter simultaneously resists being so moved-to be
moved does not mean to be moved violently (pace Newton)-and only by equating these
things would one be led to think that not resisting means not being moved, and therefore
being interpenetrated. As we will show in a few pages, St. Thomas and Aristotle are more
explicit in claiming that the aether can touch and move (per se and in all species of motion)
sublunary matter without being touched and moved in return; the {in their minds) bizarre
situation I am describing of aether being moved (per accidensand merely locally) by sublunary
matter would be contrived and more of a thought-experiment for them, but not absolutely
impossible.

390

CHRISTOPHER A. DECAEN

almost be called sensible in virtue of the noticeable connection
between certain heavenly and terrestrial motions, for example,
seasonal changes and lunar tides. Even in Aristotle's time it was
evident that these latter were the effects of the relative positions
and motions of the sun and the moon, respectively. 41 In addition,
the heavenly bodies' constant illumination of things here below
shows that the aethereal agency emanates not only from the sun
and the moon, but from the stars too, and that this agency must
communicate itself across the tremendous expanse of the aether
to reach us. Further, Aristotle and St. Thomas would argue, the
aethereal substance would produce the seasons by being the cause
not only of the changes in the length and temperature of the day,
but also in some way of the cycle of life itself, the blooming of
vegetation and the seasonal generation of animals. As Aristotle
puts it in a well-known but cryptic passage, "Man and the sun
generate man"; 42 the heavenly substance, due to the perfection of
its form, appears to be the ultimate physical cause not only of the
seasons but also of all terrestrial change. 43
Saint Thomas, developing Aristotle's aether doctrine and
perhaps suspecting that the fact that aether both illuminates the
Earth and simultaneously effects generation is not a coincidence,
suggests that it is precisely in virtue of its luminescence that
heavenly matter acts upon ordinary matter. Thus he states, "the
powers of the heavenly bodies are participated in by the inferior
bodies by the mediating of light. " 44 When we recall that Aristotle
and St. Thomas understood light to be the "act of the transparent
as such," we see that on this account light is present not merely in
41 On the sun's motion and relative position as the cause of seasonal changes, see Meteor.,
1.9, 2.2-3; De Gen. et Cor., 2.10.336a32-b19; 337al-32; on the moon's relation to the tides,
see St. Thomas, SI'h I, q. 70, a. 1, ad 5.
42 Aristotle, Phys., 2.2.194b13 (emphasis added). Saint Thomas explicitly proposes that
aether is the cause of substantial forms of all bodies here below, expanding on things Aristotle
only hinQ> at (II De Caelo, lect. 10, n. 12).
43 De Caelo, 2.1.284a9-12. This is also part of the upshot of the argument in Physics 8 that
there is a first mobile whose natural motion is circular; he is referring of course to the
heavens.
44 St. Thomas, II Sent., d. 17, q. 3, a. 1; see also II De Caelo, lect. 10, n. 12; SI'h I, q. 67,
a. 3, ad 3.

AETHER AND CONTEMPORARY SCIENCE

391

the stars but in the entirety of the aether. 45 Indeed, if we consider
that nothing around us is perfectly transparent--one can see only
so far even through air-and that the distance between the Earth
and the stars is almost inconceivable, 46 one sees that aether must
be the most perfectly transparent substance in the cosmos. Thus
St. Thomas will conclude that transparency is not only the active
but also the proper quality of the heavens; all other bodies are
called transparent only by participation in the nature of aether,
the way other things are hot by participation in the nature of
fire. 47 Further still, if transparency, rather than being merely a
privation of color, is a positive nature, as Aristotle believes, 48 we
have found our first positive quasi-sensible quality in the aether:
its supreme transparency and, in some cases, luminescence. 49
Further, considering aether's universal agency in conjunction
with its immutability, two critical consequences follow. First, we
have implicitly granted that aether acts upon ordinary matter and,
since it is inalterable, that it is not acted upon in turn by it; aether
can "push" on ordinary matter without being "pushed back."
Thus Aristotle will conclude that
While usually the thing touching is touched by what it touches-for nearly all the
things we come upon move while also being moved, and in these cases it is
necessary and apparent that the thing touching is touched by what it
touches-still it also occurs (as we sometimes say) that only the mover may touch
the moved, while the thing touched does not touch the one touching it. But
because things of the same kind are moved [in return] when they move others,
it seems to be necessary that [movers] be touched by what they touch. Whence
Aristotle,DeAnima, 2.7.418b8-9; St. Thomas, llDeAnima, lect.14, nn. 6-7.
See above, notes 1 and 4.
47 St. Thomas, II Sent., d. 13, q. 1, a. 4; STh I, q. 67, a. 3; II De Anima, lect. 14, n. 22; De
Sensu, lect. 6, nn. 7-9.
48 See De Anima, 2. 7.418b4-15. Transparency is in some way more positive than color is,
the latter being a deficient participation in lumen, whereas the former is a more perfect one.
Aristotle and St. Thomas further argue that since colors can exist in an intentional mode in
what is actually transparent, this too suggests that transparency is a higher, and therefore not
merely privative, mode of being; see St. Thomas, De Sensu, lect. 6. Note also that modem
science also implicitly denies that transparency is merely a privation; put simply, if darkness
is the privation of light and color, transparency cannot be.
49 See St. Thomas, II De Caelo, lect. 10, nn. 3 and 12-13; STb I, q. 66, a. 3, ad 4.
45

46

392

CHRISTOPHERA. DECAEN

if something unmoved moves another, although it will touch the thing moved,
nothing [will touch] it.so

Drawing on this distinction, St. Thomas notes this peculiarity of
aether:
Bodies act upon each other by touching, whence it follows that they are
simultaneously acted upon [in return], since what touches is acted upon. But this
should be understood [only] when there is mutual contact [mutuus tactus], as
happens in those things that share in a common matter, each of which is being
acted upon by the other while they are touching each other. The heavenly
bodies, however, because they do not share a common matter with inferior [i.e.,
sublunary] bodies, act upon them such that they are not acted upon by them [in
return]; they touch and are not touched.st

This one-way contact and causality may seem absurd at first
glance. While the doctrine is contrary to our Newtonian "equal
and opposite reaction" prejudices, Aristotle argues persuasively
that it is not impossible, as motion is an actuality not in the mover
as such but in the mobile. Thus it is not essential to the notion of
one thing's moving another that the latter move the former in
response. 52 Indeed, the cause of such agency being only one-way
is the aether's incorruptibility, and therefore, at least in part, the
aforementioned difference between its prime matter and ours.
Second, while aether lacks the qualities of sublunary matter, it
must be able to generate them in the latter; that is, aether must be
an equivocal cause, possessing the predicates it gives its patients
in an equivocal, or more accurately, analogous, and therefore

50 De Gen. et Cor., 1.6.323a26-32 (emphasis added). In this same passage Aristotle argues
that mutual agency and mutual contact require that both bodies have position and place. If,
however, place is not univocally said of celestial and terrestrial matter, again they must lack
mutual contact and agency; see 322b27-323a13.
SI mPhys., lect. 4, n. 5 (emphasis added); see also n De Caelo, lect. 10, n. 13; ScG n, ch.
56,n.S.
52 Aristotle, Phys., 3.2.202a3-12. Aristotle's application (and, implicitly, restriction) to
sublunary matter of his own version of Newton's third law can be spotted at De Motu Anim.,
698b13-18. Obviously if it were a part of the notion of agency that every mover be moved in
reaction, any argument from motion to God's existence would be doomed.

AETHER AND CONTEMPORARY SCIENCE

393

higher, or intentional, mode of existence. 53 For example, the sun
induces heat in the bodies around us, but it is not itself hot (for its
heat would eventually consume it, and also it would have a
natural motion upward), so it must possess heat according to a
different ratio, in such a way that heat does not inform the
aethereal matter. 54 Likewise, then, St. Thomas says that aether is
so radically unlike sublunary matter that any predicates that the
two have in common will be only analogous:
Many things that are not equivocal according to the abstracted consideration of
either the logician or the mathematician nevertheless are in a certain mode said
equivocally according to the concrete notion of the physicist applying [them] to
matter. For such [predicates or forms] are not received according to the same
notion in every matter whatsoever, just as it happens that one does not find
quantity and the unity that is the principle of number according to the same
notion [rationem] in the celestial bodies and in fire, in air, and in water ....
Some equivocations, however, are proximate, on account of an agreement in
genus, just as if "body" be said of the celestial body and of a corruptible body,
it is said equivocally, speaking according to the natures of things [naturaliter
loquendo], since their matter is not one. Nevertheless, they agree in logical genus
[in genere logico], and on account of this agreement of genus appear not to be
wholly equivocal. . . . Whence, on account of this proximity of genus or of
lik!!ness, they do not appear to be equivocations, while nevertheless they are.ss

The student of nature, paying attention not merely to the
abstracted and most generic consideration of a form-the playing
field of the logician or mathematician-will study the being of the
specific nature of a physical substance and, if necessary, will
SJ Although Aristotle does not seem to use the name "equivocal cause," he does insist that
the cause is sometimes like the effect by being only "of the same genus..•• For the hard is not
generated by the hard" (De Gen. et Cor., 1.5.320b20-22; d. also Metaphys. 7.8.1033b301034a9). On equivocal causality in general, see St. Thomas, STh L q. 4, a. 3; VIlMetaphys.,
lect. 7, nn. 16-19; lect. 8, nn. 13-27) and with reference to the heavens, see II Phys., lect. 4,
n. 10; lect. 6, n. 3; lect. 11, n. 2; VIlI Phys., lect. 10, n. 4; II De Caelo, lect. 1, n. 4; De Pot.,
q. 3, a. 11, ad 14. This higher mode of possession, while necessary, is difficult to describe; St.
Thomas refers to it variously as an "intentional," or "excelling," or "more eminent mode of
being," or as a "total," or "less contracted and more universal" form, one that is "more
dominating over matter."
54 De Caelo, 2.7.289all-35; Meteor., 1.3.341a17-19; St. Thomas, II De Caelo, lect. 10,
nn. 6-10.
ss St. Thomas, VIl Phys., lect. 7, n. 9; and lect. 8, n. 8 (emphasis added).

394

CHRISTOPHER A. DECAEN

qualify the logician's univocal predication of some terms.
Although an investigation of the relationship of the logician and
the physicist, and of that between logical and· natural genera, is
beyond the scope of this article, this much is clear: Celestial
matter's heterogeneity with mundane matter requires that it be
called a quantity, one, a body, and even matter and substance only
by way of analogy. 56
A provocative example of this ambiguity about how or whether
the heavens possess attributes like those of ordinary matter
concerns the predication of motion, place, and time. We have
seen that Aristotle attributes to aethereal matter both immutability, in virtue of which it endures through all ages, and
circular local motion, which reflects its perfection and by which
it acts upon the sublunary world. While this appears to be almost
a contradiction-a perfect lack of three kinds of change but an
inalterable possession of the fourth-it is not. For while Aristotle
admits that aether moves locally, by granting it circularmotion he
mitigates its existence as a motion. What Aristotle means by
circular motion is not the motions of the stars and planets, which
appear to be progressive motions of bodies tracing out circles.
Rather, circular motion is the motion proper to a sphere, a
revolution about its axis, and the motion of the aether as a whole:
a stationary rotation, not an orbit. 57 On this account circular
motion is not strictly a change of place, but a change within a
place. Only the parts of the heavenly sphere, and not the whole,
can leave one place and enter another. 58 The most perfect and
primary source of natural motion within the physical order is least
56 Analogy is itself analogous, and I do not mean to say that each of these is predicated
according to exactly the same sort of analogy. For example, "body" (and likewise "quantity")
is first said of heavenly and terrestrial bodies with the same notion in mind-and hence the
logician predicates these terms univocally-although in the determinate natures themselves
their corporeity is not the same. "Matter" said of the heavenly and sublunary, however, seems
to signify different notions and different realities. To see the basis for this distinction, consider
the passages quoted above in conjunction withDe Pot., q. 7, a. 10, ad 7; and STh 1-11, q. 113,
a. 5, ad 1.
57 De Caelo, 2.8, and St. Thomas, II De Caelo, lect. 12, nn. 1-4; lect. 13, n. 3.
58 See Aristotle, Phys., 4.4.21 la19-23; 4.5.212b2-13. Even the parts, the stars, do so such
that they are always approaching both the end and the beginning, namely, the center, so chat
here too the motion is somehow static.

AETHER AND CONTEMPORARY SCIENCE

395

of all in motion, both because local motion is the least of all
changes, and because circular local motion is least of all a local
motion. 59 Hence there is a sort of equivocation when we predicate
local motion of the heavens, and Aristotle may coherently say, as
he does at the end of his discussion of place, "the periphery of
that which is carried in a circle [i.e., the aether], always bearing
itself in the same way, rests ... [and] in a way moves and in a way
not." 60
For related reasons aether does not simply speaking have a
location and is only analogously in place. To the extent that
heavenly matter is not univocally said to be in motion we would
think it is at rest, and therefore in place, but Aristotle says that we
must resist or at least qualify this inference. The root of this
restraint lies in his discussion and ultimate definition of place in
Physics 4 as the "first immobile limit of the containing body. "61
Because the substance continuously filling the cosmos from the
sublunary regions to the periphery obviously has no container of
its own-it is the first container of everything else-then it must
not have a place. 62 Being itself the ultimate source and measure of
all other bodies' locations and local motions, 63 aether is not itself,
properly speaking, located.
Place may, however, be attributed to aether in secondary or
extended ways. Because the heavenly substance gives all other
things place, place may be predicated of it according to the mode
in which an effect is always somehow predicable of its per se
cause, just as, for example, "healthy" is predicated of a climate
conducive to health. Likewise, one can say aether is in place
59 See Aristotle, Pbys., 8.8-9, especially 265a13-b15; St. Thomas, I De Caelo, lect. 6, n. 7;
lect. 8, n. 13.
60 Aristotle, Pbys., 4.4.212a24, 4.5.212a35. Saint Thomas suggests a number of reasons
why the aethereal circular motion cannot be compared with the natural rectilinear motions
we experience in tangible matter, all of which suggest that there is some kind of equivocation
when we call the former a local morion; see VII Pbys., lect. 7, n. 5.
61 See Pbys., 4.1-4, especially 4.212a7-21.
62 See Aristotle, Pbys., 4.5.212a32-b21; St. Thomas, IV Pbys., lect. 7, n. 2; II Sent., d. 2,
q. 2, a. 1, conclusion.
63 See St. Thomas, IV Phys., lect. 3, n. 2; lect. 6, nn. 9, 14-16; lect. 8, n. 7; STh I, q. 66,
a. 3, ad 2; I, q. 66, a. 4, ad 5.

396

CHRISTOPHERA. DECAEN

because it is in itself, meaning merely that it is not contained by
another. 64 In addition, the celestial matter can be truly said to
have place, and even motion, per accidens and secundum
rationem, that is, in virtue of its parts having place and motion per
se.65 In any of these senses, however, there is an evident loosening
or extension of the meaning of the word "place"; place is being
said of aether only analogously. 66
The other external measure of natural bodies (besides location)
is time, and in this case too we find that there is a degree of
equivocation when it is said of the heavens. Again looking back to
Physics 4, 67 we see that the nature of time is that it be the number
or measure of motion, and the uniformity and eternity of time
come from its being the measure of local motion most of all, since
only this motion, specifically circular motion, can be interminable
and uniform. Thus, while aether's motion is not the same thing as
time, Aristotle suggests that it seems in some way to be the proper
subject of time-that is, what is being counted when one
distinguishes the before and after in motion. 68 But if the motion
of the heavens underlies time, then time cannot itself underlie and
be prior to that motion. 69 While in an analogous sense aether may
be said to be in time, meaning that it is simultaneous with time
and not utterly without per se relation to it, 70 nevertheless its
infinite duration precludes its substance being bounded or limited
by ordinary temporal predicates. Thus the heavenly substance is

See St. Thomas, IV Phys., lect. 4, nn. 9-10.
On aether's per accidenspossession of place via its parts, see St. Thomas, IV Phys., lect.
7, nn. 7-9; on its per accidens possession of local motion via its parts, see VIII Phys., lect. 7,
n. 2; I De Gen., lect. 11, n. 5.
66 This becomes still more evident when one notes that the parts of aether are only
potentially distinct &om each other, and so have place and motion only potentially or
virtually. See St. Thomas, IV Phys., lect. 7, nn. 7-14.
67 Aristotle, Phys., 4.10-14, esp. 4.11.
68 See Phys., 4.14.223b13-34; St. Thomas, IV Phys., lect. 19, n. 4; lect. 23, nn. 11-13.
69 See St. Thomas, II De Caelo, lect. 1, n. 12; De Malo, q. 16, a. 4; St. Thomas adds that
therefore aether is measured not by time but by aevum, a sort of imperfect image of the Divine
eternity; see also I Sent., d. 19, q. 1, a. 1.
70 See Aristotle, Phys., 4.12.221a9-21; St. Thomas, IV Phys., lect. 20, n. 3.
64

65

AETHER AND CONTEMPORARY SCIENCE

397

not in time; 71 more properly speaking it transcends time, or is
atemporal. 72
Although this ambiguous predication of motion, place, and
time in aether is at first perplexing, it is a necessary consequence
of making the heavens an ultimate cause and measure of place and
motion in sublunary matter. The unending rotary motion of the
heavens must evidently be motion and not rest-for it moves in a
circle-and yet also, not motion but rest in place-for it moves in
a circle. Likewise, this uniform and eternal motion is the
foundation of time, so it does not exist at or for a certain time.
Put another way, while aether is obviously a mobile (indeed, the
primum mobile), it is somehow immobile because it is an ultimate
mover. While it is obviously somewhere, it is not in place because
it somehow is place. While it obviously exists now and always, it
does not exist within time because somehow time exists in it.
Obviously there is little in common between the matter with
which we have immediate experience and this subtle and obscure
celestial matter. As St. Thomas puts it,
The celestial bodies are far away from us not only according to quantity of
spatial distance, but even more so in that few of their accidents fall under our
senses, while it is nevertheless connatural to us that we proceed from accidents,
i.e., sensibles, to cognizing the nature of some thing .... But the accidents of the
celestial bodies are of a different notion altogether [alteriusrationem] and are
wholly disproportionate to the accidents of inferior bodies. 73

We may say many things negative about aether, and what positive
predicates we may apply to it must be extensions of the first
impositions of words-they must be analogies. As Aristotle has
said, we have little to go on in determining the nature of aether;
what we do have, however, is enough to make some elementary
deductions about it, even if they finally must entail analogical
predication. While not all of these properties have survived the
71 See Aristotle, Pfrys., 4.12.221al-24, b25-31; St. Thomas, IV Pfrys., lect. 20, nn. 2-4; II
De Caelo, lect. 1, n. 2.
n St. Thomas, IV Pfrys., lect. 20, n. 6; I De Caelo, lect. 6, n. 5; II De Caelo, lect. 1, n. 2;
De Pot., q. 5, a. 4, ad 1.
73 II De Caelo, lect. 4, n. 3.

398

CHRISTOPHER A. DECAEN

test of time, the aether itself and many of these distinctive marks
have, specifically within the theories of twentieth-century physics.
But before we turn to the recent rehabilitation of aether, we must
say a few things about its precarious perpetuation, revision, and
demise in early modern physics.
II. THE FATE OF AETIIER IN CLASSICAL PHYSICS
AND TIIE SPECIAL THEORY OF RELATIVITY

A) The Not-So-Aethereal Aether of Newtonianism
The heliocentric hypothesis in the late sixteenth and early
seventeenth centuries, while it did not overturn the idea of a
heavenly aether, induced a skepticism in some about its necessity.
If the daily circular motion of the stars is attributable to the Earth
itself, the only foothold we have on aether seems to slip. Although
for Copernicus the planets and moon must still forever move in
perfect circles-thus tempering the temptation to discard the
argument of De Caelo 1.2-so must the Earth, while the outer
sphere containing the so-called fixed stars must not; thus circular
motion is not a peculiar property of aether as such. Aether, it
seems, is not to be posited to explain the night sky, since its
motion is as mundane as it is celestial.
This does not by itself respond to Aristotle's critique of void,
and therefore of the assumed emptiness of the heavens. Granting
the real possibility that the luminous part of the heavens (i.e., the
stars and planets) may not be essentially different from ordinary
matter, most of the heavenly expanse remains unaccounted for.
For if nothing is in any manner detectable there, but something
must be there, the natural suspicion would be that this physical
"something" is a different order of matter, that is, is essentially
aethereal. 74
74 Perhaps having heard an argument of this sort, Galileo takes some pains to establish the
reality of a void; see Two New Sciences, trans. Stillman Drake, 2d ed. (Toronto: Wall and
Thompson, 1989), 20-80. He even addresses the weaker Physica 4 arguments. While his
arguments about free-fall correct some of Aristotle's views, his arguments on the whole,
turning on a confused and confusing understanding of the infinite and the indivisible as
principles of magnitude, are less convincing.

AETHER AND CONTEMPORARY SCIENCE

399

While this argument may have been in the background during
the early modern era, Isaac Newton embraced aether by way of
another. Rejecting the idea of action at a distance, calling it
"inconceivable," and "so great an absurdity that I believe no man
who has in philosophical matters a competent faculty of thinking
can fall into it, "75 Newton speculated about how else to explain
the distant communication of gravitational forces mathematically
described in his Principia. Following something akin to the
Aristotelian recognition that an aethereal medium is needed as an
instrumental agent of the action of the stars on bodies around
them, Newton posited aether as the medium through which the
sun holds the planets in orbit. 76 Although unsatisfied with his
mechanical models of how aether could exercise its agency, and
hesitant to publish his general speculations, Newton does not
seem to have doubted that some such principle was necessary to
complete his account of gravitational attraction. 77 Further, and
again like Aristotle and his disciples, Newton saw light as
additional evidence for an aether, though, unlike his predecessors,
he did not see aether as the subject or medium of light.
Specifically, Newton posited aether to explain certain diffractive
and refractive properties of propagated light and related electrical
phenomena. 78 Thus while aether was needed in the heavens, it
75 Isaac Newton, "Letter to Bentley, Feb. 25, 1692-3," in Isaac Newton's Papersand Letters
on Natural Philosophy, ed. I. Bernard Cohen, 2d ed. (Cambridge: Harvard University Press,
1978), 302-3.
76 Isaac Newton, "An Hypothesis Explaining the Properties of Light," in ibid., 180-81;
Opticks, query 21, in Great Books of the Western World, vol. 34 (Chicago: Encyclopedia
Britannica, 1952). See also Ernan McMullin, Newton on Matter and Activity (Notre Dame,
Ind.: University of Notre Dame Press, 1978), 75-109.
77 On Newton's many attempts at formulating a mechanically sound aether theory, see G.
N. Cantor and M. J. S. Hodge, "Major Themes in the Development of Ether Theories from
the Ancients to 1900," in Conceptionsof Ether:Studiesin the History of Ether Theories, 17401900, ed. G. N. Cantor and M. J. S. Hodge (Cambridge: Cambridge University Press, 1981),
19-24. Newton's awareness of the severe wrinkles in need of ironing out of his aether theory
is probably one of the primary reasons he is so noncommittal about the seat and cause of
gravitational forces in the Principia.(Note that "ether" is an alternate spelling of "aether"; I
use the latter spelling, although when authors quoted use "ether" I will not change it.)
78 It also served in Newton's mind to explain certain chemical processes and the
deceleration of the pendulum in an "evacuated" vessel. See Isaac Newton, "Letter to Boyle,
Feb. 28, 1678-9," in Cohen, ed., Isaac Newton's Papers and Letters, 250-53.

400

CHRISTOPHER A. DECAEN

would have to exist here below as well; in line with Copernicus,
aether was no longer only celestial.
Many of Newton's contemporaries and successors, however,
presented a conception of light even more like Aristotle's actuality
of the transparent by arguing that light needs aether merely to
exist. While Newton insisted that light is a particle, Thomas
Young and others offered compelling arguments that light is a
wave,79 and, as Oliver Lodge would one day reiterate, "waves we
cannot have, unless they be waves in something. " 80 Implicitly
invoking an Aristotelian principle at the root of Aristotle's
rejection of void, Young and others inferred that if light is not a
substance but an accident, it must be an accident of something.
Looking to the expanse of apparently empty space across which
light radiates, wave theorists saw the presence of a luminiferous
aether. This need for a light-bearing aether was reinforced in the
nineteenth century by James Maxwell's discovery that light,
electricity, and magnetism are different aspects of the same
physical phenomenon. The empirical data and mathematical
formalism of electromagnetic theory suggest that, as Maxwell put
it, "there is an aethereal medium filling space and permeating
bodies. " 81 The electromagnetic field is not a mere mathematical
abstraction, but a description of a modality or stress in the
ubiquitous and immobile aether.
Even so, early modern revisions of aether as a medium of
gravitational and electromagnetic interactions should be carefully
distinguished from Aristotle's heavenly substance. Unlike the
latter, this new aether is in a real way not aethereal. Newton, for
example, knew that any substance lacking inertial mass, and
therefore resistance to pressure-in the language of Aristotle and
St. Thomas, intangible and perfectly yielding matter-would
violate his laws of motion; 82 it would not follow what came to be
See Thomas Young, "On the Theory of Light and Colours," PhilosophicalTransactions
of the Royal Society 92 (1802): 12-48.
80 Oliver Lodge, The Ether of Space (London: Harper, 1909), 2.
81 Quoted in K. F. Schaffner, Nineteenth Century Aether Theories (New York: Pergamon
Press, 1972), 81.
82 . Especially his third law, that "To an action there is always a contrary and equal
reaction."
79

AETHER AND CONTEMPORARY SCIENCE

401

called "classical" mechanics. Likewise, because inertial mass is
proportional to gravitational attraction, such a body would not
gravitate; universal gravitation would be not quite universal. But
most importantly, a truly aethereal substance like this would in
principle be experimentally undetectable, for it would not resist
and thereby affect measuring devices or test-particles. Although a
perfectly noninertial medium could make more substantial and
intelligible Newton's problematic doctrine of absolute space, the
immobile reference frame of true motions and the forces that
cause them, nevertheless he was adamant: Such matter would not
be "a phenomenon," and would have "no place in experimental
philosophy." 83 While admitting a need for a pervasive mediumalthough not a truly continuous one, since he embraced atomism,
and therefore also the reality of voids84-Newton granted it a very
small, but nevertheless in principle detectable, mass, and therefore
also a proportionate resistance and gravitational attraction. 85
Thus, when he retains the word "aether," he means something
that differs from ordinary tangible matter not in kind but only in
degree.
Young and Maxwell's medium of light and electromagnetism
was likewise assumed to be minimally inertial, massive, and
tangible in theory. Despite the occasional discovery of evidence
challenging the hypothesis that the luminiferous aether was
merely a more tenuous kind of ordinary matter, the hypothesis
that all matter must be inertial was not questioned. 86 The
83 Quoted by McMullin, Newton on Matter and Activity, 97. McMullin notes, however,
that Newton could not consistently hold himself to this bar; Newton knew that natural science
does not really offer an understanding of nature until it asks and tries to answer the more
philosophical questions. See ibid., 125-27.
s.. See, for example, Newton, "Letter to Boyle," 250-53; Opticks, queries 21 and 31.
85 See Newton, Opticks, query 21; McMullin, Newton on Matter and Activity, 96-101.
86 For example, there was great difficulty in identifying the luminiferous aether as a solid,
a liquid, or a gas; while its subtlety and minimal mass per volume suggested that it is gaseous,
the swiftness with which it transmitted light suggested that it is solid. likewise there were
difficulties with saying that it transmitted light as a longitudinal (i.e., compression) wave or
as a transverse wave (i.e., a displacement of the medium, like a water wave); on the one hand,
light propagates spherically, suggesting a compression wave, while polarization phenomena
suggest transverse displacement. See Henry Margenau, Open Vistas: Philosophical Perspectives
on Modem Science(Woodbridge, Conn.: Ox Bow Press, 1983), 108-9. Oliver Heaviside wrote
in 1889 that "It often occurs to me that we may be wrong in thinking of the aether as a kind

402

CHRISTOPHER A. DECAEN

electromagnetic wave was understood to be a measurable force
and transient attribute of the aether not unlike the stresses and
strains in an elastic body or set of bodies, and therefore this aether
by definition would be subject to Newtonian mechanics. 87 In
addition, the luminiferous aether was posited as the reference
frame in which Maxwell's electromagnetic field equations
obtained perfectly, and therefore was the coordinate system or
stationary container of all local motion. It was assumed to be
necessarily immobile. 88 But this assumes that place and motion, or
the lack thereof, are univocally present in the aether-unlike in
the traditional aether.
Although Newton and the others did not invoke a full-blooded
aether concept, nevertheless with the empirical success of
universal gravitation and electromagnetism came the embrace of
the reformed (or perhaps to Aristotle, deformed) aether among
physicists. This embrace lasted until the dawn of the twentieth
century and was so tight that renowned physicists would say, "We
know there is an ether," and "The probability of the hypothesis of
the existence of this element is extremely close to certainty. " 89
The aether of classical physics had the virtue of undoing what is
commonly considered an embarrassingly ad hoc Aristotelian
of matter ([an] elastic solid for instance) accounting for its properties by those of the matter
in bulk with which we are acquainted" (quoted in Schaffner, Nineteenth Century Aether
Theories, 90). Lodge was likewise cautious about making too strong an analogy between
ordinary and aethereal matter: "Ether is often called a fluid, or a liquid, and it again has been
likened to a jelly because of its rigidity; but none of these names is very much good; all are
molecular groupings and therefore not like ether" (Oliver Lodge, "The Ether and its
Functions," Nature 27 [1883]: 304). Perhaps more attention should have been paid to these
cautionary remarks.
87 Margenau, Open Vistas, 105-11. This dilution of aether until it becomes essentially
indistinguishable from ordinary matter is confirmed in the constant tendency (in Newton,
Young, Maxwell, and most nineteenth-century physicists) to imagine and treat aether, even
in the mathematical formalisms, as atomic; see ibid., 110-11.
88 See ibid., 112-13. The possibility was entertained-and then refuted (seen. 92)-that
aether was dragged along by the Earth via a convection current; convection too, however,
implies that luminiferous aether acts like ordinary matter.
89 Heinrich Hertz in 1889 and J. Chwolson in 1902, respectively, the former quoted by
Schaffner in Nineteenth Century Aether Theories, 101; the latter by Albert Einstein in "The
Development of Our Conception of the Nature and Constitution of Radiation," in The World
of Physics, vol. 2. (New York: Simon and Schuster, 1987), 295.

AETHER AND CONTEMPORARYSCIENCE

403

partitioning of nature into two essentially heterogeneous
categories of substance. Nevertheless, this homogeneity and
unification of the cosmos came at a price, for it required a
dilution of the meaning of the word "aether." This price did not
at first seem costly; indeed, it seemed to be an asset because it
rendered aether more accessible to experimentation and
mathematical conceptualization. But there were hidden expenses
that would prove problematic and insupportable. The particular
nature of classical physics' aether would make it vulnerable to a
kind of refutation that Aristotle would have considered irrelevant:
the Michelson-Morley experiment.

B) The Michelson-MorleyExperiment and SpecialRelativity
On the supposition that the immobile luminiferous aether
follows Newton's laws and resists the motion of other bodies,
physicists after Maxwell looked for ways to measure its mass and
inertial properties. In one such test at the end of the nineteenth
century, Albert Michelson and Edward Morley attempted to
estimate the speed of the Earth relative to Maxwell's stationary
medium. The idea was that a sort of aether "wind," caused by the
Earth's motion through the aether, might be detected by shining
a light in the direction of the Earth's motion and comparing it
with light shining in a direction less affected by the motion.
Taking the absolute speed of light to be the same as its speed
relative to the aether, Michelson and Morley inferred that the
apparent speed of the two light beams should not be a constant;
rather, when shining in the direction of the Earth's motion, it
should be slower than when shining in a direction perpendicular
to that motion. The experiment was done with a simple interferometer, with light rays simultaneously sent in perpendicular
directions toward mirrors, which reflected them back to the
source, where they would intermingle and betray signs of the
anticipated unequal speed in the interference pattern. Such signs,
however, did not turn up; regardle5s of direction, the light rays
seemed to travel at the same speed. Apparently there was no

404

CHRISTOPHER A. DECAEN

relative motion between the Earth and the aether. 90 Michelson
and most of his contemporaries concluded that aether near the
surface of the Earth must not be immobile but dragged along by
the Earth's motion. 91 Because of this "atmosphere" of aether, no
relative motion occurs in the Earth's immediate vicinity. This
notion of a mobile luminiferous aether, however, was soon
rejected on the basis of further experimentation. 92 How do we
explain the null-result of the Michelson-Morley experiment?
H. A. Lorentz and George FitzGerald stepped in to propose an
answer. A small but fixed contraction of matter in the direction of
the Earth's motion would shorten one arm of the interferometer,
thereby giving the light beam less distance to cover and thus
allowing it to return to the source at the same time as the light
beam directed along the other, uncontracted arm. Although he
could not offer a precise mechanism for this phenomenon,
Lorentz attributed it to some hitherto unknown influence of the
aether. 93 Lorentz-FitzGerald contraction saved the appearances
and was mathematically sound, 94 but was criticized as ad hoc,
having the virtues
of elegance nor of making new pre95
dictions. And it was finally replaced by a theory that had both.
90 Michelson and Morley's three papers, originally published in the American Journal of
Science in 1881, 1886, and 1887, are reprinted as appendices in Lloyd S. Swenson, Jr., The
Ethereal Aether: A History of the Michelson-Morley Aether-Drift &periments, 1880-1930
(Austin, Tex.: University of Texas Press, 1972), 247-85. Swenson offers a more detailed
account of the experiment at ibid., 65ff.
91 See Edmund Whittaker, A History of the Theories of Aether and Electricity, vol. 1, rev.
ed. (London: Nelsen, 1951), 390-92.
92 See Swenson, The Ethereal Aether, 190-233; H. A. Lorentz, "Michelson's Interference
Experiment," in H. A. Lorentz et al., The Principle of Relativity: A Collection of Original
Memoirs on the Special and General Theory of Relativity, trans. W. Perett and G. B. Jeffrey
(New York: Dover, 1952), 3-4. The aether "atmosphere" idea implied that light from distant
stars should undergo an aberration depending the direction from which it comes, and this
aberration is not observed.
93 See Lorentz, "Michelson's Interference Experiment," 5.
94 Lorentz-FitzGerald contraction has been recently defended by Rudoph Peierls
("Relativity," in The World of Physics, 172-73) and John Bell (quoted in The Ghost in the
Atom: A Discussion of the Mysteries of Quantum Physics, eds. P. C. W. Davies and J. R.
Brown [Cambridge: Cambridge University Press, 1986], 48-49).
95 Max Born, for example, says Lorentz's theory is full of "very artificial assumptions"
("On the Meaning of Physical Theories," in The World of Physics, 63). While there is merit
hyperbolic, given what little was then (and is still) known
to this criticism, it seems to

AETHER AND CONTEMPORARY SCIENCE

405

In 1905 Albert Einstein published his special theory of
relativity and shortly thereafter declared that the luminiferous
aether is an "outdated point of view.... [A] satisfactory theory is
only achieved by renouncing the ether hypothesis. " 96 This
revolutionary theory encompasses not just the Michelson-Morley
null-result, but also a wide range of physical phenomena.
Combining the empirically based principle that the speed of light
in a vacuum is a constant in all reference frames 97 and the
philosophical principle that all laws of physics are the same for all
coordinate systems regardless of their states of motion changes the
entire worldview or natural philosophy of mathematical
physics-so much so that the advent of relativity came to mark
the transition from so-called classical(i.e., Newtonian) to modern
physics. Put simply, Einstein's union of these two principles denies
that there is any meaning to Newton's notions of absolute space,
motion, and time. Thereby it offers what appears to be the
simplest possible explanation of the Michelson-Morley null-result:
there is no absolute reference frame for the Earth's motion, and
therefore no aether, and therefore no "aether wind," which
explains why no difference in the speeds of the two beams of light
is detectable in the interferometer. 98
Reducing measurements of time, space, rest, and motion to
mere relative terms, although philosophically problematic to
many, then and now, 99 has its merits. Not only did special
about the nature of light. Born, after all, is writing in the wake of the success of relativity
theory, which offered the account of the null-result that is still accepted; hindsight is always
20/20.
96 Einstein, "The Development of Our Conception of the Nature and Constitution of
Radiation," 295, 299.
97 This assumption of the constancy of the speed of light "in a vacuum" does not implicitly
assume that aether does not exist; I am simply following common usage. "In a vacuum," of
course, would also mean "in the luminiferous aether," until after aether was rejected.
98 There are a number of more detailed yet simple explanations of how special relativity
explains the results of the Michelson-Morley experiment; see, for example, Simon Saunders
and Harvey R. Brown, "Reflections on Ether," in The Philosophy of Vacuum, ed. Simon
Saunders and Harvey R. Brown (Oxford: Oxford University Press. 1991), 44-45.
99 Bell still insists that a Lorentz-type aether is more plausible an account of nature than
relativity, which he believes allows for time-travel and destroys any hope for a realist
understanding of nature; see The Ghost in the Atom, 48-50. Those who recognize the great
insights in the perennial philosophy of Aristotle and Thomas, of course, and therefore start

406

CHRISTOPHER A. DECAEN

relativity shed the artificiality of Lorentz-FitzGerald contraction,
it made new predictions-the most famous of which still is the
convertibility of matter and energy, empirically vindicated quite
publicly less than forty years later in the nuclear fires of
Hiroshima and Nagasaki. And with the removal of the privileged
coordinate system, the immobile luminiferous aether lost its
relevance for the physicist, for, according to the prevalent attitude
of logical positivism, what cannot be measured may just as well
not exist. 100 Within a few decades after 1905, aether became a
"metaphysical concept in the pejorative sense, " 101 as outmoded as
Aristotle's geocentric universe, 102 or his bifurcation of nature into
ordinary matter and his full-blooded, though more subtle, aether.
Yet the latter was about to make a comeback.
III. CONTEMPORARY SCIENCE'S REsUSCITATION OF AETHER

A) The Curved Space-Timeof GeneralRelativity
According to most accounts of the history of the aether in
physics, that was the end of the story. Aether is dead and the
Michelson-Morley experiment and special relativity killed it. 103
from things better known to all men, will also conclude that the "orthodox" interpretation of
relativity cannot be ttue without qualification. Unfortunately, there are few among us who
have attempted alternative interpretations; nor will I propose one here, leaving that for better
minds.
100 On the prevalence of positivism among physicists as a partial cause of the acceptance
of relativity, see Swenson, The Ethereal Aether, 185-88, 201, 231; and Bell, quoted in The
Ghost in the Atom, 49.
101 Swenson, The Ethereal Aether, 231.
102 In histories of science it is often forgotten that, ironically, according to relativity it is
as ttue to say that the sun revolves around the Earth, with Aristotle, as it is to say that the
Earth revolves around the sun, with Copernicus. In a real sense Einstein undoes Copernicus,
for he says that Copernicus and Aristotle were both right (and wrong).
103 This is ttue most often of popularized accounts, even by serious physicists; see, for
example, Margenau, Open Vistas, 114-15; Louis de Broglie, Matter and Light: The New
Physics (New York: Dover, 1939), 266. More rigorous scholarly work tends to be more
evenhanded about aether's continued tenure in recent physics; see Swenson, The Ethereal
Aether, 187ff.; and especially Ludwik Kostro, Einstein and the Ether (Montreal, Quebec:
Apeiron, 2000), passim. This latter work thoroughly explodes the myth that the mature
Einstein saw himself as -aether's hangman;· rather, Kostro shows, after 1916 Einstein

AETHER AND CONTEMPORARY SCIENCE

407

Rumors of its death, however, had been greatly exaggerated, and
a closer look at the content and history of the theories that have
been accepted in twentieth-century science makes this manifest.
Not the least among these theories is Einstein's generalized theory
of relativity, just as not the least among those who interpret this
theory in terms of aether was Einstein himself.
A decade passed between the publication of the special theory
of relativity and the 1915 completion of the general theory,
immediately after which Einstein realized that he had overstated
his case against aether. General relativity-indeed, even special
relativity-was compatible with and, in fact, implied an aether; 104
aether's "story, by no means finished, is continued by the
relativity theory. " 105 Relativity initiated a development and further
aetherealizing of the physicist's understanding of the luminiferous
aether that, we will see, bespeaks a conception more reminiscent
of the intangible substance proposed by Aristotle.
Because special relativity had seemed to discard the
luminiferous aether, we should start with it. In spite of his
hyperbole in the decade after 1905, Einstein would later temper
his remarks:
careful reflection teaches us, however, that the special theory of relativity does
not compel us to deny ether. We may assume the existence of an ether; only we
must give up ascribing a definite state of motion to it, i.e., we must by
abstraction take away from it the last mechanical characteristic which Lorentz
had still left it .... The special theory of relativity forbids us to assume the ether
to consist of particles observable through time, but the hypothesis of ether in
itself is not in conflict with the special theory of relativity. 106
consistently understood aetlter to be essential to relativity tlteory. (Note also tltat many of
Einstein's writings quoted below are available in English only in Kostro.)
164 In a number of writings, botlt published and unpublished, Einstein expresses his regret
about his overzealous claims to have eliminated aether; see Kostro, Einstein and the Ether, 12, 76.
105 Albert Einstein and Leopold Infield, The Evolution of Physics (New York: Simon and
Schuster, 1938), 153.
106 Albert Einstein. Sidelightson Relativity, trans. G. B. Jeffrey and W. Perrett (New York:
Dover, 1983), 13, 15. Lodge, a defender of aether even during the period immediately
following upon relativity's alleged elimination of it, would argue that "'A superstition has
recently arisen that the ether is an exploded heresy and is unnecessary; but that is an absurd
misunderstanding. The tlteory of relativity says nothing of tlte kind .•.. [l]gnoring a thing is

408

CHRISTOPHER A. DECAEN

Special relativity is congenial to aether as long as one withholds
from it all the properties underlying classical mechanics, such as
mass, inertial resistance, atomic composition, and even a
determinate state of motion or rest, in order to be consistent with
the Michelson-Morley experiment and the equivalence of
reference frames. Aether thereby becomes essentially unobservable
and "appears at first to be an [empirically] empty hypothesis. " 107
This, however, would be to ignore
a weighty argument to be adduced in favor of the ether hypothesis. To deny the
ether is ultimately to assume that empty space has no physical qualities whatever.
The fundamental facts of mechanics do not harmonize with this view....
[B]esides observable objects, another thing, which is not perceptible, must be
looked upon as real, to enable acceleration or rotation to be looked upon as
something real. 108

Insofar as certain aspects of "empty space" are elements in the
equations describing accelerative motions (special relativity
focuses on only uniform motions) an aether still seems necessary.
The "four dimensional space[-time] of special relativity is to some
extent a four-dimensional analogue of H. A Lorentz's rigid threedimensional aether. " 109
While special relativity is compatible with an aether (when
each is properly understood), general relativity positively demands
it in its notion of space-time curvature. Although even special
relativity employs the notion of space-time-the idea that no local
description of a body should be considered without specifying
when it is at this location-general relativity goes further,
attributing to space-time a certain quality or mutable property,
dubbed "curvature" because of the likeness between the way this
property and the curvature of a surface affect the speed and

not the same as putting it out of existence" (Oliver Lodge, "Speech Through the Ether,"
Nature 108 [1921]: 88).
107 Einstein, Sidelights on Relativity, 15.
108 Ibid., 16-17; see also Kostro, Einstein and the Ether, 95-96.
109 Einstein, Relativity; 150-51.

AETHER AND CONTEMPORARY SCIENCE

409

direction of a body's motion on it. 110 Space-time curvature,
mathematically described by a metric tensor and metric field, 111 is
general relativity's modification and reinterpretation of Newton's
gravitational force. 112 According to general relativity, then,
the metrical qualities of the continuum of space-time differ in the environment
of different points of space-time .... [T]he recognition of the fact that "empty
space" in its physical relation is neither homogeneous nor isotropic [i.e.,
uncurved] ... has, I think, finally disposed of the view that space is physically
empty. But therewith the conception of ether has again acquired an intelligible
content .... [S]pace is endowed with physical qualities; in this sense, therefore
there exists an ether. According to the general theory of relativity space without
ether is unthinkable; for in such space there not only would be no propagation
of light, but also no possibility of existence for standards of space and time
(measuring-rods and clocks), nor therefore any space-time intervals in the
physical sense. 113

Thus, aether is essential to general relativity, for it is ultimately
what is being described by general relativity-it is what the
curvature is a curvature of. True, it is no longer the privileged
reference frame of classical physics, for it cannot, properly speaking, be said to be at rest (or in any mathematically expressible
110 This appears to be an analogous rather than metaphorical predication, as space-time
curvature is mathematically similar to the curvature of certain two-dimensional surfaces. Note
that in Einstein's use of the word, the surface of a cylinder is not "curved"; his is both a looser
and a more specific (i.e., technical) use of the word than that of common speech.
111 A "metric" is possessed by a slice of space (or, in general relativity, space-time)
describable by an equation incorporating infinitesimal differences between its endpoints. If a
metric is a "tensor," it allows the components of the system or equation to be transformed
from one set of endpoints to another; thus it plays the central role in general relativity of
defining the geometry of space-time and giving the prescription for integrals and derivatives.
(Where the space is not flat, it is said to be permeated by a "tensor field.") For an in-depth
account of general relativity's metric tensor, see P. ]. E. Peebles, Principles of Physical
Cosmology (Princeton: Princeton University Press, 1993), 227-44.
112 Curved space-time is sometimes described as doing away with Newton's forces and with
gravitational agent causality in general; see, for example, Robert Lindsay and Henry
Margenau, Foundations of Physics (New York: Dover, 1957), 96, 358-61. This sort of
reductionism (ironically) applied to Newtonian physics may be precipitate, as forces seem
rather to be the effects of space-time curvature; at any rate, to attempt to explain motions in
nature without recourse to agent causes is to mistake physics for mathematics. See Aristotle,
Phys., 2.2.193b31-194bl5.
113 Einstein, Sidelights on Relativity, 18-19, 23 (emphasis added).

410

CHRISTOPHERA. DECAEN

state of motion). It is, however, the substrate of the physical
properties or quasi-geometrical structure that is "characterized
mathematically by the components of the gravitational potential
[i.e., the metric tensor], which describes the metric behavior of
this part of space, as well as its gravitational field, " 114 and
therefore also the motion of bodies in this part of space. This
aether's "state varies continuously from point to point" 115 in space
and in time, and thereby it affects the metrical properties (i.e., the
measurements of space-time variables) of any body at any point in
it.
The function of space-time curvature, and therefore of aether,
as determining how bodies move bears emphasis. At the root of
the relativistic aether's causality, like that of both the Aristotelian
and Newtonian aethers, is its role as an intermediate agent, a
medium through which one massive body-whether a planet or
an atom-could attract or in any way act upon another. According
to Einstein, no theory
involving action-at-a-distance ... merits serious consideration .... [fhus] we
will not be able to do without the ether in theoretical physics, i.e., a continuum
which is equipped with physical properties; for the general theory of relativity,
whose basic points of view physicists surely will always maintain, excludes direct
distant action. But every contiguous action theory presumes continuous fields,
and therefore also the existence of an "ether. " 116

Taking the rejection of action at a distance as a philosophical first
principle in interpreting the mathematical theory, Einstein
maintains that agent causes will act only by contact, specifically by
alterations of the space or aether surrounding distant patients, and
general relativity explains how this happens. Although Einstein's
aether "is itself devoid of all mechanical and kinematical qualities
. . . [it] helps to determine mechanical (and electromagnetic)

114 Einstein, "Dialogue concerning Accusations against Relativity.Theory," in Kostro,
Einstein and the Ether, 76.
115 Ibid.
116 Einstein, "On the Ether," in The Philosophy of Vacuum, 15, 20; see also Sidelights on
Relativity, 4-6.

AETHER AND CONTEMPORARY SCIENCE

411

events." 117 Specifically, relativity's aether determines both inertial
and gravitational motions, the former by the abstracted special
theory which makes it a principle of motions in nearly flat regions
of space, and the latter by the general theory which makes it a
principle of motions in significantly curved space. 118 So-called
empty space not only has attributes, it also has causally active
attributes, and enters into "the causal nexus of physics, . . . [so]
this ether would be a physical reality as good as matter." 119
Unlike the aether of Aristotle, however, Einstein's aether enters
into the "causal nexus of physics" by also being acted upon by
ordinary matter. The degree of curvature in a region of space-time
varies with-indeed, Einstein sometimes even says, "is generated
and defined" 120 by-the presence of ordinary matter. A massive
body curves ambient space-time, but this curvature, in turn,
determines the path and speed of that same body and of bodies
near it. While Einstein grants that aether has some sort of priority
over ordinary bodies-sometimes he says, perhaps hyperbolically,
that inertial matter is nothing more than a state or modification
of the aether 121-he nevertheless does not simply speaking attribute to it the sort of one-way causality found in the Aristotelian
aether.
Still, this is not to say that the relativistic aether is simply
another form of ordinary, Newtonian matter, for the way massive
bodies produce this curvature in the aether is not properly
explicable in terms of Newtonian mechanics. The not-so-aethereal
aether of classical mechanics-which, ironically, Einstein calls
"ether in the traditional sense" 122-is indeed a dead hypothesis.
The relativistic aether, however, is still radically unlike ordinary
Einstein, Sidelights on Relativity, 19.
m On the inertial and gravitational causality of the aether, see Kostro, Einstein and the
Ether, 166-67, 177-80.
119 Einstein, "On the Ether," 13-14.
120 Quoted in Kostro, Einstein and the Ether, 112; see also the "Morgan Manuscript," §
13, quoted in ibid., 78.
121 Albert Einstein, "The Concept of Space," Nature 125 (1930): 897-98.
122 Einstein, "Dialogue concerning Accusations against Relativity Theory," quoted in
Kostro, Einstein and the Ether, 76. Einstein never compares his aether to the Aristotelian
aether, apparently unaware that there was one.
117

412

CHRlSTOPHER A. DECAEN

matter because it does not exert a force of resistance when
massive bodies enter it and begin to generate the gravitational
field, and likewise massive bodies do not curve aether by exerting
a force or pressure on it. Rather, just as Aristotle's aether would
docilely yield to ordinary matter entering it, so Einstein's aether
naturally curves with the presence of a massive body. Thus
Einstein insists again that this is aether of "a more sublimated
form [than the luminiferous aether] ... [For it] differs from the
one of earlier optics by the fact that it is not matter in the sense of
mechanics. Not even the concept of motion can be applied to
it"; 123 thus, it "may not be thought of as endowed with the quality
characteristic of ponderable [i.e., massive, inertial] media, to
consist of parts that may be tracked through time. " 124 Not unlike
Aristotle's celestial matter, relativistic aether is deprived of
uni vocal spatio-temporal predicates, is continuous, intangible, and
perfectly transparent-for it is also the medium of electromagnetic energy, light. However, unlike Aristotle's aether (though
not perhaps directly opposed to it), this aether possesses specific
properties describable only by way of abstract mathematical formulae and geometric analogies. This substance is truly aethereal.
We find another ambiguity of predication that Aristotle and St.
Thomas noted (although for only partly overlapping reasons)
123 Einstein, "Morgan Manuscript," S 22, in Kostro, Einstein and the Ether, 78. Einstein
frequently reiterates that his aether is devoid of all predicates pertaining to motion, place, and
time, but he implicitly admits that such predicates may apply to it in an extended sense. What
Einstein is saying most precisely is that aether lacks a detenninate and mathematically
expressiblevelocity, or state of motion or rest, or a trackable temporal history at any point
within it; see, for example, Sidelights on Relativity, 13-15, 19. Relativistic aether is
nevertheless ubiquitous and has points and spatio-temporal coordinates within it, each
possessing its own distinct curvature, and which change with time-..:.anof which are spatial
and temporal predicates that must have some (perhaps nonmathematical) sense to them.
Likewise, by surrounding bodies, the relativistic aether locates them or gives them place, and
it is the substratum of space-time; therefore, it bears an intrinsic relation to space and time as
a principle of them. Thus, distinguishing analogical (i.e., rationally equivocal) from univocal
predication, and following Aristotle's account, we may rightly say that even Einstein's aether
both has and does not have place, motion, and time.
124 Einstein, Sidelights on Relativity, 23-24. Unlike the classical account of aether and
ordinary matter, general relativity's aether is not atomic; it is strictly continuous. See, for
example, ibid., 15; "On the Ether," 14.

AETHER AND CONTEMPORARY SCIENCE

413

regarding the celestial substance: Is it right to call this aether a
substance or matter at all? Einstein, after all, sometimes says that
in general relativity, "instead of speaking of an aether, one could
equally speak of physical qualities of space," and that here "the
concepts of 'space' and 'ether' merge together. " 125 Has he only
tagged the vacuum with the name "aether" without meaning to
describe a material being of any sort? Einstein cannot simply mean
this, as he just as frequently (and often in the same writings) says
that relativity has "finally disposed of the view that space is
physically empty," and that "space as opposed to 'what fills space'
. . . has no separate existence. . . . Space-time does not claim
existence on its own but only as a structural quality of the
field, " 126 that is, of the aether. What is being called "space" is not
a void, an expanse of nothingness, for it is not empty and it is
positively causal. Whether we call it a material substance, then,
seems to depend on what is meant by "matter" and "substance."
On the classical assumption that matter is the same thing as
massive, atomic, and inertial, or "ponderable," matter, the aether
would not properly be a material substance. 127 However, keeping
in mind the Aristotelian insight that matter most properly is that
out of which a physical substance is composed, and therefore is
the very potency for natural being, 128 we see that this subtle yet
mutable physical entity is essentially a material substance-though
these predicates are appropriate to it only in an extended sense. 129
As Lorentz puts it, given its function, any aether must be "endowed with a certain degree of substantiality, however different
12S Respectively, "On the Ether," 13; and "Morgan Manuscript," S22, quoted in Kostro,
Einstein and the Ether, 78.
126 Respectively, Einstein, Sidelights on Relativity, 18; and Alben Einstein, Ideas and
Opinions (New York: Crown Publishers, 1960), 375-76; on p. 15 of the former he also calls
aether an "extended physical object."
127 See Margenau, Open Vistas, 103, 114-15.
128 See Aristotle, Metapbys., 5.12, 9.1, 9.7. On the root notion of matter as "that from
which a thing is composed," see Charles DeKoninck, "Abstraction From Matter (part one),"
Laval theologique et philosophique 13 (1957): 148-62.
129 As we said earlier, the matter of aether is a potency for natural being, but not for
natural becoming, except perhaps accidentally, whether that be considered with regard to
place via the rotation of the heavenly sphere, or with regard to relativistic curvature.

414

CHRISTOPHER A. DECAEN

it may be from ordinary matter, " 130 and according to one Einstein
specialist,
In Einstein's concept of the ether there also occurs a gradual materialization of
physical space-time .... [But this means] ascribing it a specific type of
materiality, very different from the materiality of the substances we encounter
in physics, to which we refer when we [usually] use the word "matter." 131

Matter and substance, like predicates pertaining to motion, space,
and time, can be said of aether only by means of rational
equivocation, that is, by analogy. Nevertheless, granting attributes,
especially causal attributes, to "empty" space is incoherent,
Einstein, Aristotle, and St. Thomas argue; void is no longer a
possibility. So an underlying causal physical entity unlike those we
experience daily must be posited by relativity. Aether's executioner turns out to be its savior. 132
B) The "Vacuum" of Quantum Electrodynamics
The other pillar (besides relativity) on which modern physics
is based is quantum theory. Just as Einstein saw his aether as the
medium not only of gravitational fields, but also of electromagnetic ones, 133 so does the second candidate for a modern
130 Quoted in Schaffner, Nineteenth

Century Aether Theories, 115.
Kostro, Einstein and the Ether, 180; on the materiality of this aether in relation to
Einstein's search for a unified field theory, see ibid., 137, 143-44, 147. Some, on the other
hand, tend to see in relativity a dematerialization ofaether, and of nature as a whole, such that
"matter is no longer material" (Margenau, Open Vistas, 113-15, 126-27). Such a conclusion
leads one to suspect that perhaps there has been a misunderstanding of what matter really is.
132 Einstein is not alone in his opinion that aether is at the heart of his curved space-time.
See, for example, Robert Weingard, "Making Everything out of Nothing," in Philosophy of
Vacuum, 202-3; for an enumeration of others, see Kostro, Einstein and the Ether, 88-90, 98101, 185-88. Some physicists and historians of science who are aware of Einstein's aetherinterpretation of relativity tend to dismiss it as no longer tenable or "a purely artificial
concept" (Max Born, "On the Meaning of Physical Theories," 64). We should note that
Einstein explained relativity in terms of an aether on fewer occasions as years went on not
because he changed his mind, but because of Nazi physicists' use of the aether concept and
their bitter mockery of "Jewish physics," epitomized, in their eyes, by Einstein; see Kostro,
Einstein and the Ether, 137, 147, 150-52.
133 See Einstein, Sidelights on Relativity, 19, 21-23, and Kostro, Einstein and the Ether, 67, 96-97, 100, 116££.
131

AETHER AND CONTEMPORARY SCIENCE

415

aether come from a branch of quantum theory called quantum
electrodynamics. As with relativity, we will not try to explain
quantum theory in detail, 134 but will restrict ourselves to salient
points pertaining to the idea of aether.
During the decades surrounding the publication of Einstein's
theory of relativity, evidence was accumulating and another
theory developing that together indicated that all energy is
transmitted in discrete units called quanta. One of the
implications of this new theory was that the position and
momentum of a particle cannot be simultaneously determined
with perfect accuracy; the more precise the position measurement,
the less precise that of the momentum, and vice versa. Likewise,
this inverse relationship was found to apply to the combination of
energy and time-interval measurements. Most importantly,
however, this "uncertainty principle" was further shown to be not
merely a limitation in our knowledge of a particle, but even to
imply an indetermination in the particle itself. A precise position
measurement means that the particle at that moment in fact has
no precise momentum. While some have seen hints of an aether
in various parts of quantum theory, 135 the uncertainty principle
argues for it most directly and persuasively. The branch of
quantum theory connected with how electromagnetic energy (i.e.,
a photon) interacts with electrons-namely,
quantum
electrodynamics, or QED 136-posits the notion of an effervescent
and active "vacuum," which looks suspiciously aethereal.
134 Thus we will leave out discussions of Planck's constant, quantum leaps, wave-particle
duality, and complementarity. Summaries and interpretations of quantum theory have been
presented recently in this journal; see Wolfgang Smith, "From Schrodinger's Cat to Thomistic
Ontology," The Thomist 63 (1999): 49-63. For more in-depth but manageable presentations
that concern themselves with the philosophical interpretation of the theory, see the following:
David Z. Albert, Quantum Mechanicsand fu:perience(Cambridge: Harvard University Press,
1992); R. LG. Hughes, The Structureand Interpretationof Quantum Mechanics (Cambridge:
Harvard University Press, 1989); Werner Heisenberg, Physicsand Philosophy:The Revolution
in Modem Science (New York: Harper, 1958); Wolfgang Smith, The Quantum Enigma:
Finding the Hidden Key (Peru, Ill.: Sherwood Sugden, 1995).
135 See Henri Poincare, Mathematics and Science:Last Essays, trans. John W. Boldoc (New
York: Dover, 1963), 86££; Whittaker, A History of the Theories of Aether and Electricity,
2:268££.
136 QED is a part of quantum field theory, which is quantum theory with a special emphasis
on the fields associated with elementary particles.

416

CHRISTOPHER A. DECAEN

A region of space in which there is no detectable matter or
energy, even at the quantum level, is described by QED as
possessing a quantum field that is "inactive" or "unexcited." This
is the ground, or lowest possible, energy state of the field, so the
quantum system here is said to be physically empty of literally
everything detectable, a "quantum vacuum." However (to revise
a pun from Aristotle), 137 this vacuum does not seem so vacuous.
In 1925 Werner Heisenberg, who first articulated the uncertainty
principle, inferred that it requires that even this vacuum must
possess throughout a certain residual and irremovable energy,
paradoxically named "zero-point energy. " 138 Because of the
irreducible minimal uncertainty we must have about the energy
status of every point within a quantum system, even one
apparently evacuated of all energy, Heisenberg argued, the
vacuum must be allowed occasionally and spontaneously to
"fluctuate," that is, to generate real particles with real effects.
Hence, where QED says there is nothing, it also says that there
will always be the possibility that this nothing will turn into
something, even if for only an instant. 139
This sounds of course like science fiction; the uncertainty
principle must be wrong if this is what it implies. Either a
quantum system is empty or it isn't, and it is inconceivable that a
void would, even occasionally, spit out a body. There is something
right about this objection; nonetheless, vacuum fluctuations are
not objects of mere theory. Even according to theory they should
be measurable-and, disturbingly, they are. Besides nearly a
century of unblemished empirical success for quantum theory and
its cornerstone uncertainty principle, there are many wellestablished phenomena apparently intelligible only in terms of
137 See Aristotle, Phys., 4.8.216a27.

138 More specifically, he argued that the uncertainty principle implies that the mean square

average of the field in its ground state is a nonvanishing value--that is, there is a tiny but
irremovable probability amplitude for the presence, or rather generation, of a proportionately
tiny amount of electromagnetic energy. See D. W. Sciama, "The Physical Significance of the
Vacuum State of a Quantum Field," in The Philosophy of Vacuum, 139-42.
139 Zero-point energy is often interpreted, obscurely, in terms of a continuous sea of
"virtual particles" in the quantum field, so named because they are not in principle measurable
(although their effect on real particles is measurable).

AETHER AND CONTEMPORARY SCIENCE

417

these vacuum fluctuations. While the first experimental evidence
of zero-point energy turned up in the same year that Heisenberg
predicted its existence, two more recent and more deeply studied
examples bear singling out. In the 1940s certain unexplained
permutations, dubbed "Lamb-shifts," were first observed in the
spectra emitted by excited hydrogen and muonic helium. Insofar
as changes in the spectral emission of an atom are directly
connected to changes in electron structure or configuration, the
only account that was and remains forthcoming is that the vacuum
surrounding the electrons of the hydrogen and helium, in virtue
of a fluctuation or actualization of some of its zero-point energy,
is energizing them. 140
A second well-established witness to the existence of zero-point
energy in the vacuum is called the Casimir effect. Predicted by
QED in the 1940s, only in the past decade has it been directly and
accurately measured. 141 The Casimir effect is a delicate but
measurable attractive force generated, without the presence of an
electromagnetic field, between a pair of parallel metal conducting
plates; this force is inversely proportional to their separation. 142
As with the Lamb-shifts, the measure of this force is exactly that
predicted by fluctuations of the vacuum occurring around the
plates, those occurring between the plates being overcome by
those occurring outside of them. These and other phenomena, 143
then, indicate that zero-point energy seems to be more than a
theoretical entity.
Is it right to call this a vacuum at all? One physicist, reflecting
on this ambiguity in QED's use of the word, notes that

140 See Sciama, "The Physical Significance of the Vacuum State of a Quantum

Field," 144.
"Something from Nothing," Nature 362
(1993): 206-7; John D. Barrow, The Book of Nothing: Vacuums, Voids, and the Latest Ideas
About the Originsof the Universe (New York: Pantheon, 2000), 204-11.
142 More precisely, the attraction is predicted and observed to be in a subquadruplicate
ratio to the separation.
143 For more empirical evidence of fluctuations of the quantum vacuum in fields as diverse
as spectroscopy, solid-state physics, and chemical reactions, see Sciama, "The Physical
Significance of the Vacuum State of a Quantum Field," 142-50, and Aitchison, "The Vacuum
and Unification," 180-85.
141 For more detailed summaries, see C. J. Foot,

418

CHRISTOPHER A. DECAEN

The excitation and de-excitation of these modes [of the quantum vacuum field]
are interpreted as the "creation" and "annihilation" of "particles." In this
context, a new notion of a "vacuum" is introduced .... There are several
features of these vacuum states that make it hard to conceive of them as
"empty. "t44

Another concludes that QED's principles, in effect, imply
that the concept of the vacuum must be somewhat realigned. It is no longer to
be associated with the idea of the void and of nothingness or empty space.
Rather, it is merely the emptiest possible state ... the state from which no
further energy can be removed. . . . [The "vacuum"] is what is left when
everything is removed from space that can be removed. 145

The so-called vacuum is full-it is filled by the irremovable zeropoint energy--so its name will be a contradiction in terms unless
it is a vacuum only relatively or loosely speaking, that is, unless it
is empty only of a certain genus of things, while it may remain full
of something of another genus. 146 This need to say that it is
essentially full, a plenum rather than a vacuum, increases when we
recall the Presocratic dictum that is one of the first principles of
natural philosophy: ex nihilo nihil fit-nothing comes from
nothing. The sudden generation of particles or their agency is
physically impossible if there is not some matter or physical
potency permeating the "vacuum" already. Manifestations of
zero-point energy, then, not only keep us from describing it as
"empty," or a "vacuum," without further qualification, but they
also tell us that it is material, for it is that which is able to become
actual particles (of energy or massive particles). It is not, of
course, the ordinary matter of common experience.
Is it not right to call it aether, then? Although few physicists
are in the habit of calling it anything other than a vacuum-with
the constant double-speak that it is not really empty--some think
aether is a more meaningful appellation. For example, some insist
J. Hiley, "Vacuum or Holomovement," in The Philosophy of Vacuum, 222-23.
Barrow, The Book of Nothing, 205, 229.
i.,.; In chemistry, for example, a "vacuum" is not necessarily devoid of any matter, but
rather is defined as any volume of gas that exerts less than 1/1000 of an annosphere of
pressure.
144 B.
145

AETHER AND CONTEMPORARY SCIENCE

419

that the energy of the ground-state is "a kind of reintroduction of
the ether," a "quantum field-ether," although "it is a pale and
ghostly shadow of its old self," that is, of the luminiferous aether
of classical physics. 147 Indeed, the best-known proponent of
reappropriating the name and notion of aether is the founder of
QED itself, Paul Dirac. Despite special relativity's much-sung
elimination of aether, because of the enduring need to explain not
only vacuum fluctuations, but also aspects of general relativity,
Dirac argues, we should admit that we are implicitly invoking
aether in our general account of the phenomena and the
mathematical theories that pretend to be studying a void:
Physical knowledge has advanced much since 1905, notably by the arrival of
quantum mechanics, and the situation [about the scientific plausibility of aether]
has again changed. If one examines the question in the light of present-day
knowledge, one finds that the aether is no longer ruled out by relativity, and
good reasons can now be advanced for postulating an aether .... We can now
see that we may very well have an aether, subject to quantum mechanics and
conformable to relativity, provided we are willing to consider a perfect vacuum
as an idealized state, not attainable in practice. From the experimental point of
view there does not seem to be any objection to this. We must make some
profound alterations to the theoretical idea of the vacuum .... Thus, with the
new theory of electrodynamics we are rather forced to have an aether. 148

We would not be accused of reading too much into these words
to say that, at minimum, the notion of the aether is anything but
scientifically naive or reactionary. Outside of refusing to try to
make sense of QED and phenomena like Lamb-shifts and the
Casimir effect, pos1tmg a peculiarly unobservable-but
inferrable-medium seems inescapable. And what is this but
aether? Objecting to the reappropriation of the name in principle,
as though motivated by an undue syncretism, is unreasonable. As
one physicist soberly points out, in attempts to unify physics in
recent decades, "Increasingly, this vacuum is reminiscent of ether
... [and the parallels are drawn] not out of any great fondness for
147 The first quotation is taken from Sciama, "The Physical Significance of the Vacuum
State of a Quantum Field," 13 7; the second and third from Saunders and Brown, "Reflections
on Ether," 29 and 59.
148 P.A. M. Dirac, "Is There an Aether?" Nature 168 (1951): 906-7.

CHRISTOPHERA. DECAEN

420

the concept of ether, but through the perception of its unifying
role in dynamics. " 149 This is aether not merely in name, but in
function and in essence. 150
C) The Vacuum Energy of the Cosmological Constant

No claim has been made that the aether implied in quantum
electrodynamics is identical to the aether of relativity, as each
explains a different, and apparently irreducible, form of energy
149 Simon Saunders,

"Introduction," in The Philosophy of Vacuum, 7-8.

150 Perhaps the reason the name is avoided now is that there is a desire to avoid confusion,

for the Michelson-Morley experiment did indeed refute the existence of what is often simply
called "aether," and to say that QED and relativity vindicate aether may seem incoherent.
Some physicists, however, think that there is more to the common resistance to speaking of
aether now than the purely pedagogical concern, noting an instinctive hostility among other
physicists to the word "aether" when interpreting zero-point energy:
The reaction against the reintroduction of such an ether or plenum has
been so strong that any theory that dared to call on such a notion was
for a time [after the advent of special relativity] deemed to be
unacceptable and even preposterous. In the 1960s and 1970s I often
came across such a reaction when I tried to discuss de Broglie's use of
a "sub-quantum medium" as a means of providing a possible
explanation of the quantum formalism. The objection was not so much
against the attempt to find a more physically intuitive explanation of
quantum phenomenon [sic], but rather against the introduction of the
"sub-quantum medium." The retort, "Surely Einstein has shown us that
the vacuum is 'empty' and the reintroduction of such an outmoded way
of thought will not provide a satisfactory understanding of the
phenomena," was not uncommon. Yet in relativistic quantum field
theory the notion of "vacuum polarization" had already emerged and
was being used quite freely, .•• [and] Einstein himself (1924) did not
react so strongly against the notion of an ether. (Hiley, "Vacuum or
Holomovement," 219)
(Vacuum polarization is another phenomenon manifesting the existence of zero-point energy.
The 1924 reference to Einstein is to the essay "On the Ether," cited above.) Is this refusal to
countenance aether perhaps motivated by a desire to "save face," not to admit that in a sense
physicists were wrong to see the Michelson-Morley experiments and special relativity as the
definitive overthrow of aether? Hiley does not pursue the question much further, but he does
go on to say that this visceral rejection of aether as an allegedly appropriate heuristic for the
quantum vacuum and general relativity's curved space-time has been fading in the past two
decades.

AETHER AND CONTEMPORARY SCIENCE

421

(electromagnetic and gravitational, respectively). Likewise, while
QED's zero-point energy is postulated to explain the very small
(e.g., spectral variations in an excited atom), relativity's curved
space-time is postulated to explain only the very large (e.g., the
precession of Mercury's orbit around the sun). Thus, assuming
that there is only one aether filling a given space at a given time,
it is difficult to see, barring some future unification of these forms
of energy-which, admittedly, many scientists, including Einstein,
have devoted much effort to finding-how these two modern
aether-candidates can be fused. Harmonizing quantum theory and
relativity is not my aim here, as their partial incompatibility is
well known and has troubled better minds. Nevertheless, there are
some signs, courtesy of recent astrophysics, of a partial overlap
between the quantum and relativistic aethers. 151 In attempting to
understand the macro-world (e.g., stellar motions), usually the
domain of general relativity, astrophysicists are now feeling a
need to posit a macro version of QED's micro-world zero-point
energy. Thus, although the jury is still out among the physicists on
what to make of the phenomena in question-so any evaluation
must remain tentative-still the evidence should be noted.
According to accepted theory, the expansion of the universe
should be decelerating due to the gravitational drag of massive
bodies, such as planets and stars. However, observations on a
number of distant supernovae over the past ten years are
suggesting that some hitherto unknown repulsive force from an
151 While special relativity is compatible with quantum theory, general relativity is not.
However, quantum field theory, of which QED is a part, is so far the first partial
harmonization of quantum theory and general relativity, for it imitates the latter's emphasis
on the influence of the geometrical structure of space-time-which field or space-time
structure we saw was the segue into each theory's need for an aether. Recall, however, that
Einstein saw both gravitational and electromagnetic fields as aspects of one aether; see above,
note 119. Note also that Dirac himself thoughtfully argues that the quantum and relativistic
aethers are essentially compatible, different sides of the same coin. Pointing out that the
indeterminacy of the spatio-temporal predicates that relativity implies for its aether is required
by the uncertainty principle, he says that the less massive a body is, the more indeterminate
its velocity becomes; thus, if aether is massless, its velocity will be perfectly indeterminate, as
special relativity requires; see Dirac, "The Evolution of the Physicist's Picture of Nature,"
ScientificAmerican 208 (May 1963): 51.

422

CHRISTOPHER A. DECAEN

unknown energy source is accelerating the expansion. 152 And
worse, this force does not appear to be coming from one region
of the universe; rather, it appears to be coming from all
directions, or more specifically, from space itself. The comparison
with Einstein's original idea of a "cosmological constant," an
irremovable repulsive force built into the texture of the universe,
has been difficult to avoid, although for half a century it was
common opinion that its addition to relativity theory was ad hoc.
While little is certain about this accelerative force, one thing
seems clear: As one physicist puts it, "the energy density
associated with the [new] cosmological constant is not possessed
by matter or radiation, but by 'empty' space." 153
Perhaps, then, it is not coincidental that researchers have
tentatively named this mysterious energy source not only "Xmatter" (thereby treating it as material in some sense), but even
more strikingly, "quintessence," 154 the name used by Aristotle's
medieval disciples for the fifth element, aether. As one physicist
specializing in interstellar dark matter puts it,
A decade ago, it seemed to me that dark matter was a sort of modern "fifth
essence." But even closer in spirit to Aristotle's heavenly aether or "quintessence"
is the currently favored possibility that a nonzero energy exists throughout
empty space .... [P]erhaps nothing in the history of physics resembles more the
quintessence of Aristotle than ... [this] vacuum energy, comprising 50-70
percent of the energy density of the universe. 155

152 See J.P. Ostriker and P. J. Steinhardt, "The Observational Case for a Low Density
Universe with a Non-Zero Cosmological Constant," Nature 377 (1995): 600-602; James
Glanz, "Astronomers See a Cosmic Antigravity Force at Worlc," Science179 (1998): 1298-99;
idem, "Exploding Stars Flash New Bulletins from Distant Universe," Science 280 (1998):
1008-9; Barrow, The Book of Nothing, 184-92, 297-301; Lawrence Krauss,Quintessence: The
Mystery of Missing Mass in the Universe (New York: Basic Books, 2000), 107-9, 332-36.
Although this last work is mainly focused on astrophysics' search for dark matter, it is
particularly noteworthy insofar as it enumerates and explains other phenomena besides the
supernova data that suggest a need for a cosmic-scale vacuum energy; see Krauss,
Quintessence, 222-28.
IJJ Peter Coles, "The End of the Old Model Universe," Nature 393 (1998): 744.
IJ 4 Glanz, "Exploding Stars Flash New Bulletins from Distant Universe," 1008-9; Krauss,
Quintessence, 335.
ISS Krauss, Quintessence, xix, 222-23.

AETHER AND CONTEMPORARY SCIENCE

423

As in general relativity and QED, this use of the word "aether"
does not seem to be pure metaphor. Besides apparently possessing
the aethereal character of QED's vacuum, this "quintessence,"
unlike all other known matter, does not exhibit gravitational
attraction, it is not pulled or pushed toward other bodies-indeed,
it appears only to repulse or push upon ordinary matter, implying
both its uniqueness and its causal agency. Likewise, in virtue of its
dominance over ordinary matter and energy, this energy-source
seems to be the single most important factor determining the
shape of the universe, the arrangement of stars and galaxies within
it, of space itself, and the eventual fate of the universe as a whole.
Further, this mysterious energy source appears to act on ordinary
matter without being acted upon in return. Empirical data suggest
and general relativity theory requires both that it be accelerating
the expansion of bodies in the cosmos and that it remain
unaffected by their motion or presence. In short, this cosmic
vacuum energy seems to be immutable, a cosmological
constant-all of which are marks of Aristotle's weightless and
intangible, but causal, celestial substance. 156 While not identical to
Aristotle's conception of aether, this modern "quintessence" does
appear to be its intellectual heir.
CONCLUDING REMARKS

The supernova evidence of a cosmological constant is hardly
definitive. Likewise, general relativity and quantum electrodynamics are only theories-well-tested
theories (especially
QED), to be sure, but theories nonetheless, successful attempts at
making more intelligible what is observed. 157 Just as Aristotle's
geocentric universe was overturned in the sixteenth and
156 On each of these properties of the cosmological constant, see Barrow, The Book of
Nothing, 185, 244-45, 290-91, 297-301; Krauss, Quintessence, 213, 334.
157 There remain few physicists who believe that the standard interpretation of either
relativity or quantum theory is simply untrue, but many believe each is only a half-truth that
will be superseded by later, more unifying fundamental physics. Certainly there are
philosophical problems in the way the theories are articulated or made intelligible by their
proponents, the solution of which will probably require some revision of standard
interpretations.

424

CHRISTOPHER A. DECAEN

seventeenth centuries and was replaced by Copernicanism and
Newtonian universal gravitation, and just as the unthinkable
happened when Newtonian physics failed at the beginning of the
twentieth century, each proving unable to account for newly
detected phenomena, so the same may someday occur to relativity
and quantum theory. The experimental method of natural science
is tentative by nature, its inductions always being only partial and
incomplete. 158 However, just as Newtonian physics is an
approximation to the truth, so relativity and quantum theories, if
or when challenged, will turn out to have been like the truth.
Thus, they should not be dismissed as being entirely off on the
wrong track, and their different but similar needs for an aether
suggest that there is something right about the aether as a
principle of nature. At minimum one will grant that the foregoing
excursions into relativistic, quantum, and astrophysical theory and
observation amount to a powerful dialectical argument in favor of
something like Aristotle's celestial substance.
Nevertheless, it seems silly, one might say, to pretend that the
new aether-candidates are what Aristotle was trying to say all
along. After all, there are two critical ways in which they are
decidedly unlike Aristotle's aether. His first and most
straightforward reason for positing a new kind of matter is his
belief that he could see the heavens moving in a way that nothing
else around him moves. This simple circular motion was rejected
long before Einstein and Dirac formulated their revolutionary
theories, and their aethers possess no such motion. Likewise,
Aristotle's aether was peculiar to the celestial regions; it was not
"here below," whereas space-time and vacuum energy are
everywhere. Thus (the objection goes) what contemporary science
has hit upon bears only a superficial, coincidental resemblance to
Aristotle's aether.
There is, of course, something to be said for this. Aristotle's
aether is not simply identical to those implied in relativity and
an illuminating discussion of the threefold distinction among the incomplete
induction of the experimental scientist, the complete induction for which he hopes, and the
intuitive induction of per se nota propositions that are the basis of natural philosophy and of
knowledge in general, see DeKoninclc, "Abstraction from Matter," 139-45.
158 For

AETHER AND CONTEMPORARY SCIENCE

425

quantum theories, as the most obvious marks of the former are
not preserved in the latter. However, a case has been made that,
while the nightly circular motion of the heavens is no doubt what
first caught Aristotle's attention and made him suspect that there
is an unusual kind of matter up there that is not down here, the
underlying and in many ways most critical drive to posit aether is
the impossibility of void. If there cannot be a void, and yet the
senses detect nothing in the heavens besides a few shining lights,
then we are left with good reason to believe that whatever fills the
heavens is unlike any matter of which we have experience. The
circular motion of the stars, then, only adds to this conviction. 159
This situation is identical to the one 1n which we find ourselves
today. Space still appears to be empty. Certainly it is probable
that, if there were any subtle sensible attributes permeating the
heavenly regions, some sign of an ubiquitous medium of ordinary
matter, we would have detected something by now. What we have
found, from random stellar dust and gas to a uniform scattering
of microwaves, is not enough literally to fill the heavens. Sensation and even the mechanical measuring devices acting as extensions of sensation have not given us reason to believe that there is
anything but emptiness. Rather, what we have done is argue to the
existence of properties in space, properties that thereby imply a
substrate. Einstein has argued to there being a quasi-geometric
structure filling space that affects the gravitational motions of
bodies in it. Heisenberg has argued that the uncertainty principle
entails vacuum fluctuations, and therefore some kind of "vacuum
energy." Thus, the consistently vacuous appearanceof outer space,
when combined with the troublesome philosophical baggage that
comes with void, is itself an argument in favor of aether, just as
was Aristotle's wonder at the apparent emptiness between himself
and the distant stars. Modern science has only strengthened the
argument. Likewise, the modern aethers and that of Aristotle have
a common core: They are aethers of the same sort. Each posits an
159 Indeed, St. Thomas argues that circular motion is not an inseparable accident of the
heavens, arguing that the outermost heavenly sphere beyond the fixed stars, the "empyrean
heaven," is thoroughly immobile and the most foundational of the concentric spheres of
aether; see STh I, q. 66, a. 3, ad 1 and ad 2; I, q. 66, a. 4, ad 5.

426

CHRISTOPHERA. DECAEN

ubiquitous, space-filling, utterly insensible medium whose
existence we cannot directly measure or detect but which can be
inferred from things we can measure and detect.
Nor are only the basics shared. In the foregoing, we have
demonstrated profound similarities between the old and the new
aethers that are worth reviewing. Recall Einstein's curved spacetime which has no determinate velocity, location, or history;
spatio-temporal predicates can be applied to it only analogically,
not univocally. Likewise, Aristotle's heavenly matter has no place,
no motion or rest, and does not exist in time, without some kind
of loosening of the meanings of those words. Einstein's aethereal
space-time, moreover, is a principle and cause of the local and
temporal properties of ordinary matter and in some way
determines the nature of their motions. Aristotle's "first body" is
the ultimate principle in virtue of which all other bodies have
place and are measured by a common time, and it is the first
physical agent cause of natural motions. In both relativity and
QED, one finds an ambivalence among the physicists about calling
their respective aethers "material" or "immaterial"; likewise,
Aristotle and St. Thomas insist that aether can be named "matter"
and "substance" only equivocally, even occasionally arguing that
it partakes of "immateriality. " 160 Aristotle and St. Thomas, on the
one hand, argue that aether seems to be immutable and impassive
to ordinary matter, that is, it cannot be touched or pushed.
Relativity and QED, on the other hand, while admitting that
ordinary matter somehow causes curvature of space-time, and that
the relative location of conducting plates can indirectly effect a
net attracting force in the ambient quantum vacuum, require that
aether not be a ponderable or inertial sort of matter-the quasiagency of ordinary matter on it is not intelligible as common
efficient causality, which involves an equal and opposite reaction.
And lastly, Einstein, Heisenberg, Dirac, on the one hand, and
Aristotle and St. Thomas, on the other, all insist that light and
light-related phenomena have this medium as their proper subject.

160 On the latter, see St.

I De Caelo, lect. 18, n. 7; SI'h I, q. 58, a. 3.

AETHER AND CONTEMPORARYSCIENCE

427

These likenesses seem too particular yet profound to be chalked
up to coincidence. 161
But is not Aristotle's restriction of aether to the heavens
significant? Of course, and Aristotle no doubt would have secondguessed his sharply spatial bifurcation of nature if he had known
what experimental science tells us now. There is even some vague
evidence that he considered the possibility that the aether or some
kind of participation in the nature of aether could exist in the
sublunary regions. 162 Regardless, Aristotle's account would have
One could reasonably respond that nevertheless in the first book of De Caelo Aristotle
derives most of these properties from the circular motion of the heavens, which no
contemporary scientist would accept, and thus the similarities noted are indeed purely
coincidental. However, this would be to delineate too narrowly the sources of Aristotle's
doctrine about aether. For example, we see Aristotle laying the groundwork for the idea of
aether throughout the Physics, and especiallyin the fourth and eighth books in their recurring
reference to the outermost container of the cosmos as the ultimate source of place and
motion. Such is the source of his aether's nonlocalized, nonmoving, yet universally causal
properties. Likewise, this would imply aether's one-way causality, immutability, and
intangibility, all without reference to its circular motion, and these lines of reasoning are
neither opposed to nor even radicallyunlike those that drive Einstein and the others to posit
their aethers. Thus, we suggest, although the line of reasoning in De Caelo is in many ways
the most accessible, it is not the sole path of discerning aether's properties. Nevertheless,
Aristotle's emphasis on the circularity of the motion as an epistemological principle of aether's
properties makes one wonder whether some kind of circularity might still be present in the
aether, especially given that Aristotle speaks in De Caelo, 1.3, as though a natural circular
motion is somehow necessary for the perfection of the cosmos. General relativity's geodesic
light path is a possible candidate for such an aetherial circular motion, since in many other
ways it resembles Aristotle's primum mobile, although to consider this in detail would take
another paper.
162 Occasionally Aristotle seems to speak of there being some quasi-admixture of aether
with sublunary matter; see Meteor., 1.3.340b6-341a37. Much has been made of this
"sublunary aether" in recent years; see John Thorp, "The Luminousness of the Quintessence,"
Phoenix 36 (1982): 104-23; Aristotle's De Motu Animalium, ed. and trans. Martha C.
Nussbaum (Princeton: Princeton University Press, 1978), 143-64. Still, it is difficult to see
how this notion is consistent with Aristotle's overall claints that aether does not alter or
corrupt, so could not enter into the constitution of a complex substance, and that aether
moves only circularly, so could never get down here to begin with. As was said earlier,
Einstein sometimes (intemperately) claims that ordinary matter is nothing more than a special
state of aether; this precipitate conclusion derives from an ambiguity inherent in the
mathematical formalism of relativity. For relativity implies that metric tensor fields can be
found not only in "empty" space, but in all space; it seems that aether is literally everywhere,
even where something else is. Unless one is willing to grant an interpenetration of physical
substances, one must say that either the aether is the substance at that point in the field or
ponderable matter is, and Einstein takes the former option. However, we know that aether
161

428

CHRISTOPHER A. DECAEN

to be modified in this respect to make it compatible with better
data-as he himself insisted, for he said that his account was
plausible only given the information he had at present.163 Thus,
just as there must be some way in which, it now seems, ordinary
matter can act upon aether, and that particles of dust can exist in
the interstellar sea of aether, so aether seems to exist in closer
proximity and interaction with the ordinary matter around us.
Hence, we are not arguing that Aristotle's aether can be preserved
without refining and updating it; but neither has it been simply
chameleon-like, utterly changing its colors for Aristotle, then for
Newton, and then again for Einstein and Heisenberg. Indeed, if
modern physicists can see themselves as rehabilitating the
Newtonian aether in quantum and relativity theories, a fortiori
would it be appropriate to say the same about the Aristotelian
aether, which is much more like what they are talking about than
is the aether of classical physics.
"Nature loves to hide," Heraclitus said, and the evidence for
aether is a case in point. Its existence is by no means self-evident,
lengthy and
and is only detected by inference-sometimes
complicated inference, punctuated by many premises that are
merely tentative. While the argument for aether was first made by
Aristotle, and many of the fundamental insights contained in this
argument are still valid, the cause of aether has now been taken
up by the most empirically successful theories of contemporary
science. As one physicist puts it, with relativity, quantum theory,
and astrophysics, "we are going full cycle, back to the aether and
quintessence of Aristotle .... [This is] a true 'quintessence,' in the
exists at all only because we have started with the self-evident fact that ordinary matter exists
and is substantial, and to sacrifice what is evident for the sake of an hypothesis is incongruous.
Thus, a more reasonable interpretation of the pervasiveness of the field would be that, just as
aether seems to be able to exist in close proximity with ordinary matter, ordinary matter can
participate by degrees in the nature of aether, and this participation is what is symbolized by
the continuity of the mathematical formalism. Perhaps such a doctrine of aethereal
participation can be made along the lines of Aristotle and St. Thomas's doctrine of
participation in grades of transparency in all bodies; see Aristotle, De Sensu et Sensato,
3.439a21-25; and St. Thomas, De Sensu, lect. 5. The connection between aether and light (or
electromagnetism) is not accidental.
163 See above, note 10.

AETHER AND CONTEMPORARY SCIENCE

429

spirit of Aristotle. " 164 The allegedly different subjects of natural
science and natural philosophy have reached the same conclusion,
though by way of somewhat different means, suggesting that
perhaps the disjunction between the philosopher and the scientist
has been too radical and thorough. The myth that experimental
science invariably refutes the perennial natural philosophy, and
that the aether in particular is a prime example of the casualties
of this conflict, is itself being rethought and repudiated. Phoenixlike, the aether, after having received what appeared to be a
mortal wound, is still with us in both philosophy and
experimental science, and it bids fair to remain. 165

164 Krauss, Quintessence,

332, 335.
Gratitude is owed to Stephen Baldner, Peter Orlowski, Ronald Richard, and my wife
Rose, who read and offered many helpful comments on an earlier version of this paper. The
remaining mistakes are, of course, my own.
165

The Thomist 68 (2004): 431-67

THOMAS AQUINAS ON CELESTIAL MATTER
STEVEN BALDNER
St. Francis Xavier University
Antigonish, Nova Scotia, Canada

I

T HAS BEEN FORTYYEARSsince the publication of Thomas Litt's

magisterial study of Thomas Aquinas's doctrine of the heavenly
bodies. 1 That work provides a comprehensive and accurate
presentation of the Thomistic understanding of the heavens: their
nature, motion, causality, place, and purpose in the universe. It
remains the indispensable scholarly source for understanding
Thomas's teaching on these topics. Nevertheless, it has established
one tenet of the Thomistic position that I wish to challenge.
According to Litt, 2 and most other commentators as well,3
Thomas Aquinas holds that the heavenly bodies are incorruptible
because they are composed of a prime matter that is different
from the prime matter of earthly bodies.
The problem arises as follows. Thomas as a good Aristotelian
understands that all material substances are composed of form and
1 Thomas Litt, Les corps celestesdans l'univers de saint Thomas d'Aquin (Louvain & Paris:
Publications Universitaires, 1963).
2 Ibid., 6-7.
3 John Wippel, The Metaphysical Thought of GodfreyofFontaines (Washington, D.C.: The
Catholic University of America Press, 1981) 286-87; Edward Grant, Planets, Stars, and Orbs:
The Medieval Cosmos, 1200-1687 (Cambridge: Cambridge University Press, 1996), 250-51;
Michel-Pierre Lehmer, Le monde des spheres I: Genese et triomphe d'une representation
cosmique (Paris: LesBellesLettres, 1996), 142-43; Joseph Bobik,AquinasonMatterandForm
and the Elements: A Translation and Interpretation of the De Principiis Naturae and the De
Mixtione Elementorurn of St. Thomas Aquinas (Notre Dame: University of Notre Dame Press,
1998}, 199-205. On the other hand, Robert Pasnau, Thomas Aquinas on Human Nature
(Cambridge, Cambridge University Press, 2002), 137, claims that there cannot be two kinds
of prime matter in Thomas's doctrine.

431

432

STEVEN BALDNER

matter. By virtue of one and only one substantial form, any
substance is what it actually is. This means that whatever is
actually true about the substance, just insofar as it is substance, is
caused by the substantial form. On the other hand, by virtue of
matter in the most basic sense, which is prime matter, any
substance is liable to substantial change; that is, it is liable to
become a completely new actual thing. This means that both
generation and corruption are possible because substances are not
merely actual; they are potentially other, and they are so because
of prime matter. To put this another way, it is because of prime
matter, and only because of prime matter, that a substance is
subject to substantial corruption. But if this is so, then it seems
that one can claim that a material substance such as a heavenly
body is incorruptible only if one says that it does not have prime
matter in the sense in which other material substances have prime
matter. That is, if the heavenly bodies have a different sort of
prime matter, which has an appetite for only one substantial form,
then one could explain the incorruptibility of the heavenly bodies
by asserting that the prime matter of heavenly bodies is different
in kind from the prime matter of earthly bodies. This is just the
position attributed to Thomas Aquinas by Litt and by those who
have followed Litt's interpretation of Thomas.
I intend to show, however, that Thomas's position was not
always, and was not finally, what has just been described. Thomas,
in fact, altered his position in important ways more than once.
Under the influence of his teacher, St. Albert the Great, Thomas
in his early works held an Averroistic position, that the heavenly
bodies are not composed of form and matter. In his maturity,
when he wrote the Prima pars of the Summa Theologiae,Thomas
did hold the position attributed to him by Litt. In his last works,
however, such as his commentary on the De caelo of Aristotle,
Thomas seems to have adopted a third position, namely, that the
heavenly bodies are incorruptible by virtue of form, not by virtue
of matter. To show this, I shall discuss three topics: the doctrine
of Averroes and Albert on the incorruptibility of the heavens,

AQUINAS ON CELESTIALMATIER

433

Thomas's early position in the 1250s, and Thomas's mature
position in the 1260s and 1270s.
I. AVERROES AND ALBERT ON THE
INCORRUPTIBILI1Y OF THE HEAVENS

The principal text for the statement of Averroes' position, and
one that was certainly influential on Albert's paraphrase of De
caelo, is De substantia orbis,4 although the same position can be
found elsewhere (e.g., in Averroes' De caelo).5 In some general
way, says Averroes, it is true that the heavenly bodies, like the
earthly, are "composed." In heavenly matter, no less than in
earthly, there must be "two natures," one that is passive or
receiving and another than is active or giving.6 This will clearly be
the case in the heavenly bodies, for in them something must be
the mover and something else must be the thing moved. The
motor and the motum will be present in the heavenly bodies, but
they must somehow be distinct.
It is also clear, however, that what is meant by form and matter
in the heavenly bodies will be something quite different from
what is meant by those terms in earthly bodies, because the
heavenly bodies are incorruptible and the earthly are both

4 Averroes, Sertno de substantia orbis, in Aristotelisopera cum Averroiscommentariis, vol.
9 (Venice: Apudjunctas, 1562) f. 3-14. In giving the position of Averroes, my intention is to
give only the Latin position, of which Albert was aware. I am not making claims about the
historical accuracy of the attribution of this position to Averroes.
5 Averroes, Commentaria de Caelo, in Aristotelisopera cum Averroiscommentariis,vol. 5
(Venice: Apudjunctas, 1562), lib. 1, t.c. 20, f. 15C-D; lib. 1, t.c. 95, f. 63L-64A. As Edward
Grant rightly points out, Averroes "bedevils" the problem by saying (De caelo, lib. 1, t.c., 21,
f. 15K) that the "heavenly body does not have matter" (Edward Grant, "Celestial Matter: A
Medieval and Galilean Cosmological Problem," Journal of Medievaland RenaissanceStudies
13 [1983]: 161). Such a declaration by Averroes gave both Albert and Thomas some hesitation
in interpreting him. Averroes does not, however (if I am correct), ever mean to say that the
heavenly body is not material; he means to affirm that it is a material body but he wants to
underscore the point that it is not a composed body. Hence it does not have matter, as any
composite of matter and form could be said to have matter and to have form.
6 Averroes, De substantia orbis, cap. 1, f. 3B-E.

434

STEVEN BALDNER

generable and corruptible.7 This observation leads Averroes to
provide a general discussion on the difference between accidental
and substantial change, with a view to bringing out what is
required for substantial change. 8 In order for substantial change
to occur, it is necessary that the substance that is to undergo the
change not possess the form of the substance into which it will
change. And in order that it not possess the form into which it
will change, it is necessary that its matter be prime matter, matter
that is in potency to all forms. 9
A basic feature of all material substances is the fact that they
are divisible, and this divisibility belongs to bodies insofar as they
have quantity. Quantity in three dimensions is a kind of primary
accident of all material substances, and having actual dimensions
is a product of the substantial form. 10 In other words, the proper
quantitative dimensions of a material substance are consequent
upon having a certain substantial form. 11 What is true of the
fundamental accident of quantity is true of the other accidents as
well: they inhere in complete subjects that are composites of form
and matter. By form, the subjects are actual; by matter, they are
potential. Actual accidents cannot inhere in a purely simple reality
(such as prime matter), because being subject to a contrary (which
is required for any change) implies being already something in act.

7 "Quod autem hae duae naturae [scilicet, forma et material existentes in his generabilibus
et coelestibus corporibus non sint convenientes specie manifestum est, posito corpore coelesti
ingenito et incorruptibili, et corporibus, quae sunt apud nos, genitis et corruptibilibus" (ibid.,
cap. 1, f. 3E).
8 Ibid., cap. 1, f. 3G-4K.
9 "[Aristoteles] invenit transmutationem individuorum in suis substantiis cogere subiectum
non esse ens in actu, et non habere formam, qua substantiatur. Si enim haberet formam,
nullam aliam reciperet, nisi ilia destructa: unum enim subiectum habere plusquam unam
formam est impossible. • •• Unde natura huius subiecti recipientis substantiales formas,
videlicet primae materiae, necesse est ut sit natura potentiae, secundum quod potentia fit eius
differentia substantialis. Et ideo nullam habet formam propriam et naturam existentem in
actu: sed eius substantia est in posse: et ex hoc materia recipit omnes formas" (ibid., cap. 1,
f. 3K-L).
10 Ibid., cap. 1, f. 3M - 4A.
11 Averroes means, I think, that a substance's general (proper) size is determined by its
substantial form, but, of course, the exact size of this or that substance is determined by
accidental considerations.

AQUINAS ON CELESTIAL MATIER

435

This observation, however, suggests to Averroes a conclusion
that is of the greatest importance. Since what is purely simple
cannot receive contraries, prime matter itself cannot be purely
simple: if it were, it could not receive a form, for no form could
be the contrary of a purely simple prime matter. As we have seen,
dimension is fundamental to material substances. It is by
dimensions th<it there is a fundamental contrariety among
substances; the natural size or dimensions of one substance is
contrary to the natural dimensions of another substance. The
point is that contrariety must be directed at something actual, and
dimension is the actual contrary opposition involved in all
substantial change. Prime matter, the subject of substantial change,
is never completely stripped of dimensions; it always possesses
indeterminate dimensions.
And because Aristotle discovered that all forms communicate in indeterminate
dimensions, he knew that prime matter is never stripped of indeterminate
dimensions, because, if it were so stripped, a body would come to be from a nonbody, and a dimension from a non-dimension. And in that case, corporeal
[substantial] forms would be contraries that succeed each other in the subject,
according to its disposition to substantial forms. 12

Averroes insists that prime matter must have in itself
indeterminate dimensions in order that substantial change be able
to take place. He will call this a "form of indeterminate
dimension" that necessarily inheres in prime matter, without
which substantial change could not take place. 13
Averroes provides an example for us. 14 Consider the change of
the substance water into the substance air. If we heat water, the
12 "Et quia invenit [Aristoteles] omnes formas communicari in dimensionibus non
terminatis, scivit quod prima materia nunquam denudatur a dimensionibus non terminatis,
quia, si denudaretur, tune corpus esset ex non corpore, et dimensio ex non-dimensione: et
tune formae corporales essent contrariae, et succedentes sibi in hoc subiecto, sicut est
dispositio de formis substantialibus" (Averroes, De substantia orbis, cap. 1, 4B-C).
13 "Et, quia illa forma, scilicet dimensionis non terminatae existit in prima materia
primitus, et succedit sibi in ea, cum impossibile sit hoc subiectum recipere duas earum in
eadem parte existentes terminatae quantitatis, ideo impossibile est a subiecto denudare
formam, vel subiectum denudari ["denadari" in text] a forma, nisi per formae destructionem"
(ibid., cap. 1, f. 40).
14 Ibid., cap. 1, f. 4C-D.

436

STEVEN BALDNER

volume of water expands until such a point that the volume of the
water is equal to that which air would occupy, and at that point
the water changes into air. Similarly, when air is cooled, its
volume decreases until it reaches the natural volume that water
would occupy, and at that point the air changes into water. The
natural volume of water is opposed as a contrary to the natural
volume of air. And this opposition depends upon a reception of
contrary quantities in the subject of substantial change, prime
matter. Prime matter, thus, must possess dimensions but not in a
determinate way. "Dimensions in an unqualified way, which are
called 'body in an unqualified way,' are never stripped from prime
matter, just as common accidents are never stripped from any two
or more contrary bodies, like transparency, in which fire and
water communicate. " 15
What explains the possibility of generation and corruption also
explains, by its negation, incorruptibility in material substances.
Corruptibility requires contrariety with respect to the form and a
common subject that does not itself have a form but is in potency
to other forms. The basis of all of this is a subject (prime matter)
that receives in itself indeterminate dimensions and is thus many
things in potency. 16 On the other hand, if the subject (prime
matter) did not have dimension in itself, it would not receive a
diversity of forms, neither numerically nor specifically. Rather, it
would have only one form. 17 Furthermore, it could not receive
other forms, for its subject would not be able to admit of any
multiplicity of forms, neither potentially nor actually.
And the cause of this is that [the subject, prime matter] does not receive quantity
first, before the reception of forms, because if it had received [quantity first], it
would be divisible according to form, and its form would be divisible according
u "Dimensiones igitur simpliciter, quae appellantur corpus simpliciter, non denudantur a
prima materia, sicut nee alia accidentia communia omnibus corporibus contrariis, aut duobus,
aut pluribus, v.g. diaphaneitas, in qua communicant ignis et aqua" (ibid., cap. 1, f. 40).
16 "Et causa huius totius est, quod hoc subiectum recipit primitus dimensiones interminatas,
et quia est multum in potentia" (ibid., cap. 1, f. 4F).
17 "Quoniam, si [subiectum] non haberet dimensionem, non reciperet insimul formas
diversas numero, neque formas diversas specie ["spe ci" in text], sed in eodem tempore non
inveniretur, nisi una forma" (ibid., cap. 1, f. 4F-G).

AQUINAS ON CELESTIAL MATIBR

437

to dimensions, that is, by a division of its subject. And its acts would be finite in
quantity, and its form could receive more and less, whole and part. If, therefore,
there is some form that does not receive more and less, that is not divided by a
division of its subject, and whose subject is not divided by a division of form (i.e,
admits no diversity}, it is clear that in the subject of that form dimensions do not
exist first, but only after form exists. 18

The key point then is the following. Substantial change is only
possible when prime matter is in itself not absolutely simple but
has a form of indeterminate dimension, by virtue of which the
prime matter is able to receive a diversity of substantial forms.
Averroes stresses that this quantitative form must inhere in prime
matter first, or that it is naturally prior to substantial form, in
order that substantial change be possible. If this prior quantitative
form is missing from matter, then the matter is not able to receive
different or other substantial forms. Such matter lacking the form
of quantity would be simple and would not be liable to substantial
change. Such simple matter will in fact be the matter of the
heavenly bodies.
Accordingly, Averroes reports, Aristotle explains the
incorruptibility of the heavenly bodies by the fact that such bodies
do not have a subject that is receptive of division or dimension
before the existence of a substantial form.
Since, therefore, it had been declared by Aristotle what is needed for generable
and corruptible things, on the part of the subject and on the part of the form,
from which there is generation and corruption in sensible beings that exist as
individuals per se, and [since] it has been declared that heavenly bodies are
neither generable nor corruptible, [Aristotle] has denied that they [the heavenly
bodies] have a subject that receives number and division through the existence

18 "Et causa in hoc est, quia [subiectum] non recipit quantitatem primo, ante receptionem
formarum: quia, si reciperet, esset divisibile secundum formam, et forma divisibilis secundum
eius dimensiones, scilicet per subiecti divisionem, et finiti essent actus secundum finitatem
illius quantitatis, et essetpossibile in ea formam recipere maius et minus, partem et totum. Si
igitur aliqua forma est, quae non recipit maius et minus, neque dividitur per divisionem
subiecti sui, neque subiectum dividitur per divisionem formae, scilicet -per eius diversitatem,
manifestum est quod in subiecto istius formae non existent dimensiones primitus, sed
postquam forma existit" (ibid., cap. 1, f. 4H-I).

438

STEVEN BALDNER

of simple dimensions in it first before the existence of form, and [he has denied]
that they [the heavenly bodies] are potentially many and numerically one. 19

Furthermore, when Aristotle noted that the actions of the
heavenly bodies are infinite (for they move forever), he concluded
that their substantial forms are not in subjects through the
mediation of dimensions and that they are not the powers in
bodies. 20 In other words, the forms of the heavenly bodies are not
truly substantial forms but are separate movers. They are, in fact,
both the efficient and the final cause of the motion of the
heavenly bodies; they are that by which the heavenly bodies are
moved and that to which they are moved. 21 In this the forms of
the heavenly bodies are quite different from the substantial forms
of earthly bodies, for in earthly bodies that by which the body is
moved and that to which it is moved are always different. This
difference, furthermore, explains why the movers of the heavenly
bodies, unlike earthly movers, can be infinite. 22 This consideration
moved Aristotle "to opine" that the forms of the heavenly bodies
could not be constituted through their subjects, for otherwise their
motion would have to be finite, like that of earthly substances. 23
In the second chapter of De substantia orbis, Averroes
elaborates on the relation between the heavenly body and its
19 "Cum igitur fuerint declarata ab Aristotele ista propria rebus generabilibus et
corruptibilibus ex parte subiecti, et ex parte formae, ex quibus accidit istis entibus sensibilibus
generatio et corruptio, scilicet individuis existentibus per se, et fuit declaratum de corporibus
coelestibus ipsa esse neque generabilia neque corruptibilia, negavit ea habere subiectum
recipiens numerum, et divisionem per existentiam simplicium dimensionum in eo primo ante
existentiam formae, et ipsa esse in potentia multa, et unum numero" (ibid., cap. 1, f. 4L-M).
20 "Quando ergo invenit [Aristoteles] eorum actiones esse infinitas, concludit formas eorum
non esse in subiecto mediantibus dimensionibus, sed eas non esse potentias in corporibus"
(ibid., cap. 1, f. 4M).
21 "necesse est ut forma, qua [corpus coeleste] movetur sit ilia, ad quam movetur" (ibid.,
cap. 1, f. SE).
22 "In formis enim constitutis per sua subiecta differunt, scilicet quia forma, qua moventur,
non est ilia, ad quam moventur, et ideo omnis forma huiusmodi, scilicet quae movetur ad
seipsam perficiendani per formam aliam, necesse est ut suum movere sit finitum, cum non
mover, nisi quando movetur" (ibid., cap. 1, f. SE-F).
23 "Et hoc etiam est unum eorum quae moverunt Aristotelem ad opinandum quod formae
corporum coelestium non sunt constitutae per sua subiecta, quoniam tune motus eorum essent
finiti" (ibid., cap. 1, f. SF).

AQUINAS ON CELESTIAL MATIER

439

separate mover. Fundamentally, the relationship of heavenly body
to its form is that of body to soul. 24 Yet it is clear in the case of the
heavenly body that the nature of that body is quite different from
the nature of its soul, because the soul of the heavenly body is a
mover only and is not a form in composition with matter. 25 The
heavenly body itself is a corpus simplex that is not composed of
form and matter. 26 The soul or form of the heavenly body is a
separate mover that is not itself moved, not even accidentally, as
are the souls of animals on earth. 27 The "matter" of the heavenly
body is in fact a subject that is actually existent.
The heavenly body is as it were the matter of the separate form, by which the
matter is existent in act. And therefore it is likened to matter only in this respect,
that it is receptive of form; and therefore it is more rightly called a "subject" than
"matter." Matter that is here [i.e., on earth] is called "matter" insofar as it is
essentially in potency to form, but it is called "subject" insofar as it is informed,
that is, insofar as it is a composite of form and matter. 28

The separate forms are simple beings (not complicated with
various sensitive and appetitive powers as are animal souls), and
these separate forms are the eternal causes of motion and being in
the heavenly bodies. 29
Averroes' position then is this. Substantial change requires the
presence of a "form of quantity" or a "form of dimension" to be
present in prime matter before the substantial form. Prime matter
24 Ibid., cap. 2, 6A.
25 "Sed, quia anima, quae est in corpore coelesti, non est innata moveri circulariter ab eo,

quod est innatum circulariter moveri, quia non est anima in eo, ut in corpore gravi aut levi,
cum ipsum moveatur ex se ab anima, ideo animam habet tantum, and non habet aliud
principium" (ibid., cap. 2, 6C).
26 "Et quia declaratum est hoc corpus [coeleste] esse ingenerabile, et incorruptibile, apparet
quod est necesse ut sit corpus simplex, non compositum ex materia, et forma" (ibid., cap. 2,
6D).
27 Ibid., cap. 2, 6E-G.

28 "Corpus

autem coeleste est quasi materia istius formae abstractae, qua est materia
existens in actu. Et ideo non assimilatur materiae, nisi in hoc tantum, quia est materia fixa ad
recipiendum formam. Et ideo dignius dicitur subiectum quam materia. Materia enim quae est
hie, dicitur materia, quia est in potentia forma in eo fixa, et dicitur subiectum, quia est fixa
formae, et fit compositum ex materia et forma" (ibid., cap. 2, 6G-H).
29 Ibid., cap. 2, 6H-K.

440

STEVEN BALDNER

thus has quantity in an indeterminate way in itself and apart from
substantial form. Such prime matter allows for substantial change,
for substantial change requires an opposition in quantitative
dimension before there can be an introduction of a new
substantial form. If matter does not have such inherent
indeterminate quantity, it is not liable to acquire new substantial
forms. But such matter, lacking indeterminate quantity, is
precisely the matter of the heavenly bodies. That matter is given
determinate dimensions by its form and is thereby made a simple,
not composed, material being, and its form is not a true
substantial form. It is rather a separate mover, and as a separate
mover it is able to cause an eternal (or infinite) motion. The
separate mover may be called a "soul," but it is not the kind of
soul that is joined to a body, for the soul that moves the heavenly
body must be an eternally unmoved source of motion and being.
This Averroist position is adopted by Albert in his paraphrase
of Aristotle's De caelo, where Albert gives in summary form
Aristotelian arguments drawn from the Physics and the
Metaphysics to show that there is but one system of the heavens
that is moved by the Prime Mover. Albert expresses some
tentativeness in attributing these arguments to Aristotle, 30 but he
is confident that the position is broadly Peripatetic and that it is
accurately the position of Averroes, as expressed in De substantia
orbis. 31 In fact, the chapter in question is less a paraphrase of
Aristotle than a paraphrase of Averroes.
First, says Albert, we speak about prime matter to indicate a
substance existing in potency that in itself has absolutely no form
in actuality. 32 Prime matter is the potential principle of a
substance. If prime matter were actual or formal in any way, it
would not be prime matter. By virtue of privation, prime matter
30 Alberti Magni, De caelo et mundo, lib. 1, tract. 3, cap. 4, in Alberti Magni, Opera
Omnia, tomus 5, pars 1, eel Paul Hossfeld (Cologne: Aschendorff, 1971), 63.63-66. (fhe last
series of numbers is a reference to page and line numbers: page 63, lines 63 to 66. The page
number will be given before the point, the line number after.)
31 De caelo, lib. 1, tract. 3, cap. 4 (Cologne 64.77-81).
32 "Dicimus igitur notum esse ex his quae determinata sunt in primo Plrysiconnn,materiam
primam esse substantiam in potentia existentem et nullam omnino formam habentem in actu;
sed est simplex substantia in potentia existens" (ibid. [Cologne 62.15-19]).

AQUINAS ON CELESTIAL MATIER

441

is liable to change and hence to receive a new form. Now there
are two kinds of form, accidental and substantial. 33 Substantial
form is naturally prior to accidental, since accidents inhere in and
are dependent upon substances.
There are, however, two fundamentally different kinds of
substantial form. One is divisible, subject to dimensions, and
finite; such a substantial form is the act and perfection of a body,
in which the form exercises its power. Such a substantial form is
the form of any terrestrial, material substance. 34 It is the sort of
form that we normally intend when we talk of substantial form.
The other kind of substantial form, however, is neither divisible
nor subject to dimensions nor finite, and it is neither the actuality
nor the perfection of any body. This second kind of substantial
form is called an Intelligence or an Intellect, and it is the
substantial form of a heavenly body.
Let us first consider the properties of the substantial form that
is the act and perfection of a body. 35 Such a form is finite, because
its operation is realized through a body, and no body can be
infinite. No power of any corporeal substance can, therefore, be
infinite. Furthermore, such a form must also be the form of a
divisible, quantitatively dimensional substance, even though prime
matter in itself is not divisible. Matter must be capable of
receiving dimensions, but it must not of itself have any
determinate dimensions, for if it did it would itself be liable to
generation and corruption. Its primary function, however, is to
serve as an incorruptible substrate for generation and corruption.
Prime matter, therefore, must receive a form of corporeity, prior
33 Ibid. (Cologne 62.34-41).
34 "Est autem

duplex forma substantialis, quarum una est divisibilis et quasi dimensa et
finita divisione et dimensione et finitione materiae et ilia proculdubio actus et perfectio
corporis est, habens virtutem in corpore, sicut diximus in octavo Physicorum.Altera autem
nee divisibilis est.nee dimensa nee finita per materiam et haee non est actus alicuius corporis
nee perfectio ipsius, sicut est forma, quae dicitur intelligentia sive intellectus" (ibid. [Cologne
62.42-50)). When Albert says that the substantial form is "divisible," he cannot mean that the
form itself is divisible but that it is the form of a divisible body. Form, even accidental form,
is not itself divisible but is so only insofar as it is the form of something that is divisible. See
Alberti Magni, Physica, lib. 3, tract. 2, cap. 12, in Alberti Magni, Opera omnia, tomus 4, pars
1, ed. Paul Hossfeld (Cologne: Aschendorff, 1987), 191:73-77.
35 De caelo, lib. 1, tract. 3, cap. 4 (Cologne 62.50-77).

442

STEVEN BALDNER

to receiving substantial form, by which it is rendered divisible and
subject to determinate dimensions. This form of corporeity is
common to all terrestrial material substances. Albert paraphrases
Averroes' De substantia orbis (cap. 1):
the corporeity of matter, which is like a primary form for all other forms that are
corporeal perfections, remains in the substance and is never stripped from it in
any corporeal change. If it were stripped away, a body would [come] to be from
a non-body, and a body would come to be from nothing, which we have shown
(in the First Book of the Physics) to be impossible according to nature. 36

The fact that prime matter is made divisible and susceptible of
determinate dimensions is attributable to the form of corporeity;
but the form of corporeity does not give the substance its actual,
determinate dimensions. 37 It is the substantial form that gives rise
to the actual determinate dimensions, and also to the active
qualities that are proper to the substance. Terrestrial substances,
then, are explained by the following principles. Prime matter
accounts for the basic potentiality of the substance; the fact that
it can potentially acquire some new form, whether accidental or
substantial, is attributable to prime matter. The fact that terrestrial
substances are divisible and subject to quantity is attributed to a
form that is naturally prior to the substantial form; this form is
the form of corporeity, which is a common form to all terrestrial
substances. The form of corporeity, however, does not specify any
actual, determinate dimensions or qualities. It is the substantial
form which determines specific quantities and qualities.
The substantial form that is an Intellect or an Intelligence, and
that is the form of a heavenly body, has a rather different relation
to its substance. 38 Such a form is a universal agent of sorts; it
knows in its way all possible forms, and in its intellectual
36 "corporeitas materiae, quae est sicut forma prima respectu omnium formarum, quae sunt
perfectiones corporeae, remanet in ipsa, et numquam dedudatur ab ipsa in aliqua
transmutatione quorumcumque corporum; et si denudaretur, contingeret, quod corpus esset
ex omnino non-corpore et quod fieret corpus ex nihilo omnino, et hoc ostendimus impossibile
esse secundum naturam in primo Pbysicorum"(ibid. [Cologne 62.80--63.6]).
37 Ibid. (Cologne 63.7-44).
38 Ibid. (Cologne 63.45-60).

AQUINAS ON CELESTIAL MATIER

443

operation is not limited by any body. It cannot, therefore, be the
actuality or perfection of any body. Now prime matter, which is
potentially all things, is in itself receptive of this kind of
substantial form, and it is receptive of this form before any
corporeity. This means that the matter of the heavenly body
remains indivisible, and hence incorruptible, for it never has the
form of corporeity. The heavenly body is material but it is so
without the form of corporeity, and it is this form of corporeity
that is the principle of divisibility. That which is not divisible
cannot receive contrary qualities, for contrary qualities require
spatially different parts, and spatially different parts imply
divisibility. Since the heavenly body cannot receive contrary
qualities, it is not liable to corruption. It is, therefore,
incorruptible.
It would be wrong, however, to suppose that the heavenly
bodies are not corporeal or do not have corporeal dimensions.
They are bodies and they do have determinate dimensions, but
these dimensions are given to the body by the first cause, which
constitutes them in being.39 They do not arise from the generation
of a substantial form out of the potency of matter. In the case of
the heavenly body, the matter is simply constituted as a body by
its maker and it is given a substantial form, but the substantial
form is not the act of the body. The relationship between the
Intelligence and the heavenly body is compared by Albert to the
relationship between the human body and the human soul. There
is, it should be noted, a kind of dualism in Albert's account of
human nature, 40 but this dualism makes Albert's account of the
heavenly bodies more plausible.
39 "determinavitAristoteles, quod tales formae suntnon constitutae per subiectum sive per
materiam, quemadmodum corporum formae omnes per materiam constituuntur quoad hoc
quod educuntur de materia sicut actus de potentia. Sed potius omnes istae sunt constitutae a
causa prima secundum omnes origines caelorum et caelestium corporum" (ibid. [Cologne
63:84-91)).
40 Steven Baldner, "Is St. Albert the Great a Dualist on Human Nature?" Proceedingsof the
American Catholic PhilosophicalAssociation67 (1993): 219-29; idem, "St. Albert the Great
on the Union of the Human Soul and Body," American Catholic PhilosophicalQuarterly 70
(1996): 103-20.

444

STEVEN BALDNER

Aristotle has said that [the Intelligences] are separate substances, and for this very
reason he has also said that the intellect of man is given from outside. Every form
brought from potency into actuality is restricted to the potency of matter and can
only have a limited operation. When matter is made actual, it is then divided or
not divided by way of corporeity, as we have said. Hence every form brought
forth from the potency of matter is consequent upon corporeity. 41

From the discussion I have given of this text, it is clear that
Albert understands the Aristotelian position to be that there is one
prime matter, but this one prime matter can either be liable to
division, and hence corruption, or not so liable. If it is liable to
corruption, it must have a presubstantial form of corporeity
through which it is united to its substantial form. If it is not liable
to corruption, it does not have the form of corporeity and it is
simply made by God to be an actually existing thing in a certain,
determinate way. It does not become an actually existing thing by
having a substantial form brought into existence from the potency
of matter. This actually existing material thing is united, not
substantially, but dualistically to a "form" or intelligence or
mover. Such is the incorruptible matter of the heavenly bodies.
Four chapters later in his paraphrase of De caelo, Albert again
confirms the position expressed above, that the heavenly bodies
are made of a matter that does not have any inherent
indeterminate dimensions. 42 The forms of the heavenly bodies are
not divisible materially and cannot be made many by matter; such
forms are probably different from one another as species rather
than as individuals made different by matter. 43 Albert does,
however, express some doubt about the true position of Averroes.
Averroes might mean that the heavenly bodies are pure forms
without matter and that there really is no matter at all in the
41 "dixit Aristoteles eas esse substantias separatas et hoc eadem de causa dixit intellectum
hominis ingredi ab extrinseco, quia omnis forma de potentia ad actum secundum potestatem
materiae educitur et non potest esse nisi limitatae operationis, quia cum materia efficitur actu,
tune dividitur et non dividitur nisi per corporeitatem, ut diximus, ideo omnis forma educta
de materia sicut de potentia, est consequens corporeitatem" (De caelo, lib. 1, tract. 3, cap. 4
[Cologne 63:91-64:7]).
42 De caelo, lib. 1, tract. 3, cap. 8 (Cologne 72:31-42).
43 Ibid. (Cologne 72:76-90).
.

AQUINAS ON CELESTIALMATTER

445

heavens. 44 Such a view, however, is absurd, for the obvious reason
that the heavenly bodies are observable to our senses. Such bodies
must, if we can really see them, have matter that is recognizable
by its potency for local motion.
Later in De caelo, Albert confirms the position given above. 45
One quotation from this chapter sums up the reason for the
incorruptibility of the heavenly bodies: "[the heavenly body] has
matter that naturally receives form before dimension, a form that
is separate and that gives being to it. "46

II. THOMAS'S EARLY PosmoN ON THE
INCORRUYTIBILllY OF THE HEAVENS

In the years between 1252 and 1258 (possibly as late as 1259),
Thomas composed his commentary on the Sentences of Peter
Lombard and also his commentary on Boethius's De Trinitate. 47
In both of these works, Thomas expresses approval of the
Averroist position on the matter of the heavenly bodies.
In the commentary on the Sentences, Thomas asks the question
(in the context of his discussion of the six days of creation),
whether there is one matter for all bodily creatures. 48 There are
two philosophical positions on this question, says Thomas, and
each position has its followers. One position is that of Avicenna,
according to whom there is only one matter for all corporeal
beings, for the reason that all corporeal beings are equally
material beings, and hence "matter" means the same thing for all
corporeal beings.49 Since matter has the same meaning wherever
Ibid. (Cologne 73:35-47).
Decaelo, lib. 2, tract. 1, cap. 1(Cologne104.7-47).
46 "ipswn [corpus caeleste] habet materiam, quae etiam per naturam ante dimensionem
accepit fonnam, quae fonna est separata, et ilia largitur ei esse" (ibid. [Cologne 104:18-20]).
47 Jean-Pierre Torrell, Saint Thomas Aquinas, vol. 1: The Person and His Work. trans.
Robert Royal (Washington, D.C.: The Catholic University of America Press, 1996), 332, 345.
48 II Sent., d. 12, q. 1, a. 1, resp. (Scriptum super libros Sententiarum, ed. Pierre
Mandonnet [Paris: Lethielleux, 1929] pp. 301-4).
49 "Avicenna ••• videtur ponere unam materiam esse omnium corporwn, argwnentum ex
ratione corporeitatis asswnens, quae cum sit unius rationis, una sibi materia debetur" (II Sent.,
d. 12, q. 1, a. 1 [Mandonnet, ed., 302)).
44

45

446

STEVEN BALDNER

it is found, the reality of matter is the same reality wherever it is
found.
The other position, says Thomas, is that of Averroes, who
refutes the position of Avicenna. Averroes, according to Thomas,
reasons as follows. 50 Since matter in itself is in potency to all
forms, and since it cannot be simultaneously under all forms, it
must be the case that matter is actually found under one form but
is in potency to the others. But if this is the real passive potency
of matter, there must also be an active potency capable of bringing
that passive potency into actuality, otherwise the passive potency
would be in vain. But, in fact, there is no active potency that can
actualize the supposed passive potency of the matter of the
heavenly bodies. The evidence that there is no such active potency
is found in the fact that there is no contrary to the perfect circular
motion of the heavenly bodies. Hence, as Averroes says, there is
no prime matter in the heavenly bodies. This means that the
heavenly bodies are simple material beings, not composed of
matter and form, as are the four earthly elements and those things
made of them.
One possible objection to this Averroist position is that the
heavenly bodies could be composed of form and matter, provided
that the form were so overwhelming that no potency would
remain in the matter for some other form. A kind of super-form
could completely satisfy the appetite of prime matter for form,
and thus prime matter would be the ultimate substrate of all
corporeal beings, both in the heavens and on earth. Against this
objection, Thomas responds that the potency of matter is only

so "Hane autem positionem Commentator improbare intendit in princ. Caeli et mundi et
in pluribus aliis locis, ex eo quod cum materia, quantum in se est, sit in potentia ad omnes
formas, nee posit esse sub pluribus simul, oportet quod secundum quod est sub una inveniatur
in potentia ad alias. Nulla autem potentia passiva invenitur in natura cui non respondeat aliqua
potentia activa, potens earn in actu reducere; alias talis potentia frustra esset. Unde cum non
inveniatur aliqua potentia naturalis activa quae substantiam caeli in actum alterius formae
reducat, quia non habet contrarium, sicut motus ostendit, quia motui naturali ejus, scilicet
circulari, non est aliquid contrarium ut dicitur in I Caeli et mundi, text. 20, oportet quod in
ipso nihil inveniatur de materia prima inferiorum corporum" (II Sent., d. 12, q. 1, a. 1, resp.
[Mandonnet, ed., 302); see also Averroes, De caelo, lib. 1, text. 20 f. 15C-D.

AQUINAS ON CELESTIAL MATIER

447

satisfied by its acquiring of the form to which it is in potency. 51
Prime matter is in potency to all substantial forms. Hence, the
only way in which the entire potency of prime matter could be
terminated by form would be for the matter to be actually united
to all possible forms at once-an obvious impossibility. The fact
that one substantial form is nobler than another does not mean
that the more noble form removes the potency for some less noble
form. Fire is a higher or nobler element than earth, and yet prime
matter under the form of fire remains in potency to the form of
earth. Even if we suppose that the form of the heavenly body is
the most noble of corporeal forms, it would still not remove the
fundamental omnipotentiality of prime matter.
Furthermore, this objection would imply that the heavens are
subject to generation and corruption. 52 If one supposes that there
is but one prime matter, both in the earthly elements and in the
heavenly bodies, then one must also suppose that it is the form of
the heavenly body that makes it a heavenly body and not an
earthly element. But if the prime matter out of which both are
composed is the same, then the form of the heavenly body could
also make the matter of an earthly element into a heavenly body.
The fact that such a thing would not happen does not remove the
possibility that it could happen; but the fact that it could happen
is precisely what it means to say that the heavens are generable
and corruptible.

51 "Nee potest dici, quod materiae prout est sub forma caeli, tota potentia terminetur, ita
quod nihil remaneat in eadem potentia ad aliam formam; non enim terminatur potentia nisi
per adeptionem formae, ad quam erat in potentia; unde, cum materia prima secundum se
considerata sit in potentia ad omnes formas naturales, non poterit tota ejus potentia terminari
nisi per adeptionem omnium formarum. Non enim una forma recepta in materia, etiam si sit
nobilior et magis perfecta, tollit potentiam ad formam aliam minus nobilem; materia enim sub
forma ignis existens, adhuc remanet in potentia ad formam terrae. Unde etsi forma caeli sit
nobilissima, nihilominus tamen, recepta in materia prima, non terminabit totam potentiam
ejus, nisi simul cum ipsa recipiantur omnes aliae formae; quod est impossible" (II Sent., d. 12,
q. 1, a. 1, resp. [Mandonnet, ed., 302]).
52 "Et praeterea si poneretur quod forma caeli per suam perfectionem, totam materiae
potentiam terminaret, adhuc oporteret quod materia stans sub forma elementari, esset in
potentia ad formam caeli, et reduceretur in actum per actionem virtutis caelestis; et ita caelum
esset generabile et corruptibile" (II Sent., d. 12, q. 1, a. 1 [Mandonnet, ed., 302-3]).

448

STEVEN BALDNER

Behind Thomas's response to this objection are two important
tenets of Thomistic natural philosophy. First, if there is a real
potency for something in nature, the potency must in due course
be realized in act, for nature does not operate in vain. 53 Hence, it
would not make sense to Thomas to say that the heavens are in
principle corruptible but that they in fact will not corrupt. If the
natural principle of their corruptibility is really present, then they
must be corruptible and they must in fact undergo corruption.
Second, prime matter is recognized to be a real principle of
substantial composition because it explains substantial change. 54
When we come to recognize the reality of substantial
change-that a genuinely new substance is coming into
being-then we are in a position to show that there must be a
subject of this change and that this subject must be completely
without form or privation. Such a subject, of course, is prime
matter. Would we recognize the existence of prime matter at all
if there were no substantial change? Perhaps we would not, but
Thomas does point out, later, when commenting on Aristotle's
Physics, that the principles of matter and form are not only
principles of becomingbut also principles of being.55 In order for
a material substance to exist, Thomas will say later, it must be
SJ See above (note 50): "Nulla autem potentia passiva invenitur in natura cui non
respondeat aliqua potentia activa, potens earn in actu reducere; alias talis potentia frustra
esset" (Il Sent., d. 12, q. 1, a. 1, resp. [Mandonnet, ed., 302]). See also I De cae/o, lect. 8, 11
91: "nihil est frustra in natura." One might raise an objection thus: if it is true that the passive
potency of matter must always be realized in act, this would mean that all possible natural
forms must exist, in the past, now, or in the future. This seems to imply that there can be no
unrealized natural substance; all possible material beings must be actual beings. If, then, a
unicorn or the Loch Ness Monster is a possible being, it must in due course become an actual
being. The answer to this objection is that the omnipotentiality of prime matter is a
potentiality for all natural forms, but not all merely possible forms (forms which involve no
logical contradiction) are natural forms. Only those forms that have actually been created or
will be created are natural forms. Hence, the omni potentiality of prime matter is a potentiality
for forms that natural processes could bring about. The potency of prime matter is not
equivalent to mere logical possibility. I thank William E. Carroll for raising this point.
54 Two important texts in which Thomas argues for prime matter as the subject of
substantial change are De principiisnaturae, c. 1and2; and I Physic., lect. 13. Joseph Bobilc's
translation of and commentary on the first text is helpful (Bobik,Aquinas on Matter and Fonn
and the Elements, 1-33).
ss I Physic., lect. 13, 11 111.

AQUINAS ON CELESTIAL MATIER

449

composed of prime matter and substantial form. In his earlier
commentary on the Sentences, however, Thomas is of the opinion
that a material substance can exist that is not composed of prime
matter and substantial form, for such are the heavenly bodies.
Finally, Thomas makes it clear that he does not mean that
indeterminate (or prime) matter is common to the heavenly and
earthly bodies and that some merely determinate (secondary)
matter is not common. 56 Some think, wrongly, that matter in
some primary sense can be common but that matter in a
secondary sense can be determined to be different by different
kinds of motion. Such a view is wrong, however, because different
kinds of motion are a sign, not a cause, of different kinds of
matter. The very different sort of motion in the heavenly
bodies-their natural circular motion-is an indication that the
matter of the heavenly bodies is very different from that of the
earthly. The matter of the heavenly bodies and that of the earthly
bodies are simply not common at all.
We shall consider one last objection and Thomas's reply to it.
The fifth of the initial objections in the article we have been
examining is as follows. 57 Moving bodies are, of course, material
bodies. Whenever two moving bodies have the same sort of
motion, they must also have the same sort of matter. But heavenly
bodies and earthly bodies do have the same sort of motion,
namely, local motion. They must both, therefore, have the same
sort of matter.

56 "Nee dico, sicut quidam dicunt, quod conveniunt in materia, si sumatur pro fundamento
primo, quod nee est album nee est nigrum, ut dicitur in I Metaph., text. 16, sed differunt in
materia secundum quod materia determinatur per motum; diversitas enim motus est signum
diversitatis materiae, et non causa, sed e converso: quia motus est actus existentis in potentia;
unde oportet quod ubi invenitur una materia per essentiam, inveniatur potentia respectu
ejusdem motus, secundum quod materia est in potentia ad plura" (II Sent., d. 12, q. 1, a. 1,
resp. [Mandonnet, ed., 303)).
57 "Praeterea, secundum Philosophum in IIMetaph., text. 11, neeesse est imaginari materia
in re mota. Ergo quaecumque conveniunt in aliquo motu, videntur in materia convenire. Sed
loci mutatio communis est superioribus et inferioribus corporibus. Ergo et materia" (II Sent.,
d. 12, q. 1, a. 1, arg. 5 [Mandonnet, ed., 301)).

450

STEVEN BALDNER

Thomas's response to this objection is that matter is, in the first
instance, the subject of generation and corruption. 58 Matter is the
subject of other motions only insofar as it is taken in some
secondary sense, that is, as it is understood to be more or less
perfect (per prius et posterius), depending upon whether the
motion for which it is a subject is more or less perfect. Hence,
prime matter, matter in the most basic sense, is found only in
those things that are subject to generation and corruption. But
prime matter is also found, as a consequence, in things subject to
increase, decrease, and alteration, for these three kinds of
accidental change all presuppose generation and corruption. (True
increase and decrease always involve corruption and generation,
and alteration eventually results in corruption and generation.)
Local motion, however, is quite different from these other
accidental changes.
Local motion, as is proven in Book VIII of the Physics, is the most perfect,
because nothing changes in that which is intrinsic to the thing that moves.
Hence, the subject of this kind of motion is a thing that is complete in substantial
being and in all of the intrinsic properties of the thing. Such motion belongs to
the heavenly body. Its matter, therefore, is like a complete substance among the
earthly bodies, as the Commentator says in the book, De substantia orbis. Hence
the matter is common [to the heavenly and the earthly bodies] only by analogy.59

In this passage Thomas makes it clear that he endorses the
position of Averroes, which is that the existence of prime matter
58 "Ad quintum dicendum, quod, sicut in I De Gen., cap. iii, dicitur, materia est immediate
subjectum generationis et corruptionis; aliorum autem motuum per prius et posterius, tanto
plus quanta illud secundum quad est mutatio, majorem perfectionem motus praesupponit: et
idea in illis tantum est unitas materiae primae quae in generatione et corruptione conveniunt,
et per consequens etiam ilia quae conveniunt in tribus motibus, scilicet augmento, et
diminutione, et alteratione, secundum quod augmentum et diminutio non est sine generatione
er corruptione, quae etiam alterationis terminus est" (II Sent., d. 12, q. 1, a. 1, ad 5
[Mandonnet, ed., 304]).
59 "Sed loci mutatio, ut in VIII Physicor. probatur, est maxime perfecta, quia nihil variat
de eo quad est intraneum rei; unde subjectum hujus motus est ens completum in esse primo,
et in omnibus proprietatibus intraneis rei; et talis motus convenit corpori caelesti; et ideo
materia ejus est sicut subjectum completum in istis inferioribus, ut dicit Commentator in lib.
De substantia orbis; unde remanet communitas materiae secundum analogiam tantum" (II
Sent., d. 12, q. 1, a. 1, ad 5 [Mandonnet, ed., 304]).

AQUINAS ON CELESTIAL MATTER

451

necessarily implies generation and corruption. Where there is no
generation and corruption, as in the heavenly bodies, there is no
prime matter. Where there is no prime matter, there is no
composition of matter and substantial form. The heavenly bodies,
hence, are not composed of matter and form; they are of
themselves simple bodies and are like complete, composed earthly
substances in that they are substantially complete.
Shortly after the composition of the commentary on the
Sentences, Thomas composed (1257-58) his commentary on
Boethius's De Trinitate. In a question devoted to the division of
speculative sciences (lect. 2, q. 1), Thomas treats the problem of
whether the divine science (taken either as philosophical metaphysics or as revealed theology) treats of immaterial beings. The
fourth initial objection and Thomas's reply are instructive for us.
The fourth objection is that whatever exists is either pure
matter, pure form, or a composite of matter and form. 60 An angel,
however, is not pure form, for if it were it would be pure act, but
only God is pure act. Neither is it pure matter. It is, therefore a
composite of form and matter. From this fact one must infer that
divine science, which treats of angels, concerns things that are
material.
The first part of Thomas's response to this objection is as
follows.
It ought to be said that act and potency are more common than matter and form.
And thus, even if there is no composition of matter and form in the angels, one
is able to find in them potency and act. Matter and form are parts of that which
is composed of matter and form, and hence the composition of matter and form
is only found in those things that have one part related to the other as potency
to act. Furthermore, what is able to be is also able not to be, and hence it is
possible to find one part with the other and also without the other. And hence,
as the Commentator says in De caelo, book 1, and Metaphysics, book 8, the

60 "Praeterea, ut videtur Commentator dicere in principio Physic. [comm .. 1], omne quod
est, vel est materia pura, vel forma pura, vel compositum ex materia et forma. Sed Angelus
non est forma pura, quia sic esset actus purus, quod est solius Dei; nee est materia pura. Ergo
est compositurn ex materia et forma. Et sic scientia divina non abstrahit a materia" (In Boet.
De Trin., lect. 2, q. 1, a. 4, arg. 4 [ed. M Calcaterra, in Opuscula theologica, vol. 2 (Rome:
Marietti, 1954), 375]).

452

STEVEN BALDNER

composition of form and matter is only found in those things that are naturally
corruptible. 61

In agreement with Averroes, Thomas holds that the composition
of form and matter is found only in those beings that are naturally
subject to generation and corruption. Since the heavenly bodies
are not subject to generation and corruption, they are not
composed of form and matter. They are, however, material
beings. Averroes allows that there can be instances of pure
matter-material beings not composed of form and matter-and
Thomas accepts this Averroistic tenet as an explanation for the
heavenly bodies.
One might object that, in the case of the heavenly bodies,
accidents (such as shape) are perpetually caused to be by their
subjects, for the heavenly body perpetually makes its shape to be,
as shape is an accident flowing from the substantial reality of the
heavenly body. If this is so, then one might think that a heavenly
body could also be perpetually composed of form and matter. But
the two cases, says Thomas, are not parallel. A substance causes
its proper accidents as an active potency; given the existence of
the substance, the accidents proper to the substance flow naturally
from the essential nature of the thing. The relation of matter to
substantial form, however, is very different.
Matter is not the cause of form in the way in which [a substance is the cause of
its proper accidents], and therefore any matter that is subject to some form is
also able not to be subject to that form, unless, by way of exception, matter
could be joined to form by some extrinsic cause. We believe, for example, that
61 "Ad quartum

dicendum, quod actus et potentia sunt communiora quam materia et
forma. Et ideo in Angelis, etsi non inveniatur compositio materiae et formae, po test tamen in
eis inveniri potentia et actus. Materia enim et forma sunt partes compositi ex materia et forma
et ideo in illis invenitur tantum compositio materiae et formae, quarum una pars se habet ad
aliam ut potentia ad actum. Quod autem potest esse, potest etiam non esse, et ideo possibile
est unam partem inveniri cum alia et sine alia, et ideo compositio materiae et formae non
invenitur, secundum Commentatorem in I Caeli et Mundi [comm. 20) et in VII Metaph.
[comm •• 4) nisi in his, quae sunt per naturam corruptibilia" (In Boet. DeTrin., lect. 2, q. 1, a.
4, ad 4 [Calcaterra, ed., 377)). Litt, too, recognizes that Thomas in this text is adopting the
position of Averroes. Litt, however, regards this text as an aberration from what he takes to
be the consistently held position of Thomas that there are two kinds of prime matter; see Litt,
Les corps celestes, 86-88.

AQUINAS ON CELESTIAL MATIER

453

by divine power the resurrected bodies, although composed of contraries, will
be maintained incorruptibly. 62

In two early works, the commentary on the Sentences and the
commentary on Boethius's De Trinitate, Thomas affirms the
Averroist position on the matter of the heavenly bodies. Material
beings that are composed of prime matter and substantial form are
by that very fact necessarily liable to generation and corruption.
Since the heavenly bodies are neither generable nor corruptible,
they cannot be composed of matter and form. They are dearly
material bodies, for we can see them, but they must be simple,
noncomposed units of matter. Thomas will often say, in his early
works, that the matter of the heavens is different from the matter
on earth. He does not mean that there are two kinds of prime
matter. He means, rather, that the material substances here below
are composed of prime matter and substantial form and that the
matter of the heavenly bodies is pure, that is, without any
composition at all.

III. THOMAS'S MAJURE PosmoNS ON THE
INCORRUPTIBILITY OF THE HEAVENS

After the 1250s, Thomas did not again endorse the position of
Averroes. In fact, as we shall see, when Thomas treated the
problem of the matter of the heavenly bodies formally, he rejected
Averroes' position as an absurdity, for he recognized that all
material bodies, including the heavenly bodies, must be composed
of form and matter. The problem, then, is how to explain the
incorruptibility of the heavenly bodies while affirming also that
they are composed of substantial form and prime matter, like all
other material bodies.
I have found some difficulty in determining Thomas's position
in his maturity, for reasons that will be brought forth, but there
62 "Materia autem non est hoc modo causa formae, et ideo omnis materia quae subset
alicui formae, potest etiam non subesse, nisi fortassis a causa extrinseca conteneatur, sicut
virtute divina ponimus aliqua corpora, ex contrariis composita, esse incorruptibilia, ut corpora
resurgentium" (In Boet. De Trin., lect. 2, q. 1, a. 4, ad 4 [Calcaterra, ed., 377]).

454

STEVEN BALDNER

are two things that Thomas always affirms. First, he always
affirms that in some sense the matter of the heavenly bodies is
different from the matter of the earthly bodies. He expresses this
in various ways: the matter of the heavens is alia et alterius
rationis or it is omnino diversa from that on earth; or he says that
omnium corporalium non est eadem materia or non est eadem
materia corporis caelestis et elementorum. On the other hand,
Thomas does not say that there are two kinds of prime matter or
that the prime matter of the heavens is different or diverse from
that on earth. In some way the matter of the heavenly bodies is
different from that on earth, but what does that mean? At the very
least it means that a different sort of matter is found beyond our
atmosphere from the matter that is found here. That is, the four
elements (fire, air, water, and earth) are found in our realm, but
the moon, the planets, the sun, and the stars are made of the fifth
element, ether. None of the kinds of matter found down here are
found up there; there is a complete diversity of matter in the two
realms. But does the claim that the matter of the heavens is
completely diverse from that on earth mean something more?
Does it mean that there is a different kind of prime matter in the
heavens from that on earth? To this question, as I shall show
below, Thomas appears to give two answers, although perhaps
they can be reconciled.
Second, Thomas always affirms that the form of the heavenly
body so perfects the matter that there is no privation remaining in
the heavenly body for substantial change. In some way, the form
is the cause of the incorruptibility of the heavenly bodies. It is a
different sort of form from that which is found in earthly
substances; it is able, so to speak, to satisfy completely the desire
of matter for form. But why is it able to do so? Is it because of the
form alone, that is, because the form is of such eminence that it
can satisfy the omnipotency of prime matter? Or is it because the
prime matter of the heavens is a different sort of prime matter
from that on earth, different in such a way that it is ordained to
one form only?

AQUINAS ON CELESTIAL MATIER

455

Thus, although Thomas always says that the matter of the
heavens is different from that on earth and that the form of the
heavenly bodies is the reason that there is no privation in the
heavenly bodies, neither of these claims determines an answer to
the question of whether there are two kinds of prime matter. It is
consistent with both claims both to affirm and to deny that there
are two kinds of prime matter. What, then, does Thomas
explicitly say about this question?
In the Prima pars (STh I, q. 66, a. 2), 63 Thomas deals with the
problem of whether there is one matter for all corporeal beings.
He does so, as in his commentary on the Sentences, in the context
of his discussion of creation and the six days. In the Summa
Theologiae, Thomas rejects the position, which he attributes to
Plato, that the matter of the heavens is not really different from
that below. On the basis of observation we know that the motion
of the heavenly bodies is fundamentally different from that of
earthly bodies. We also know that there are no motions or
qualities contrary to those of the heavenly bodies. The matter of
the heavenly bodies, therefore, must be different in order to
explain the fundamental difference in motion and activity.
Thomas also rejects the position of Avicebron, according to whom
matter is one and the same for all corporeal beings, by virtue of
a common "form of corporeity." This view is rejected because it
implies a plurality of substantial forms and, hence, that there
really is no substantial change but only accidental change.
Setting aside Plato and Avicebron, an Aristotelian would say
that no form remains in the substrate of substantial change. 64 This
63 The first part of the Summa Theologiaewas written in 1265-68 (see Torrell, St. Thomas
Aquinas, 333).
64 "Supposito autem quod nulla forma quae sit in corpore corruptibili, remaneat ut
substrata generationi et corruptioni, sequitur de necessitate quod non sit eadem materia
corporum corruptibilium et incorruptibilium. Materia enim, secundum id quod est, est in
potentia ad formam. Oportet ergo quod materia, secundum se considerata, sit in potentia ad
formam omnium illorum quorum est materia communis. Per unam autem formam non fit in
actu nisi quantum ad illam formam. Remanet ergo in potentia quantum ad omnes alias
formas.-Nec hoc excluditur, si una illarum formarum sit perfectior et continens in se virtute
alias. Quia potentia, quantum est de se indifferenter se habet ad perfectum et imperfectum;
unde sicut quando est sub forma imperfecta, est in potentia ad formam perfectam, ita e
converso.-Sic ergo materia, secundum quod est sub forma incorruptibilis corporis, erit adhuc

456

STEVEN BALDNER

Aristotelian point, however, implies that matter as the
fundamental potency for substantial form, that is, prime matter,
must be different in corruptible beings from what it is in
incorruptible beings. The principle is the following. Whenever
matter is common to more than one thing, it must be in potency
to the various forms of the different things to which it is common.
If such common matter is determined by one form, it remains in
potency to the other forms. No one form among those to which
the matter is common, even if it should be the best of all of the
forms, could remove this potency, for the potency is in the very
nature of matter. Hence, the potency of the prime matter found
in corruptible beings will always remain; and this potency is
precisely a potency to acquire some other form than the one to
which it is currently united. If such prime matter were united to
the form of a heavenly body, the matter could acquire another
substantial form: but that is just to say that the heavenly body
would be corruptible.
Here Thomas rejects, in no uncertain terms, the proposed
Averroistsolution to the problem. 65 Averroes imagines (fingit) that
the heavenly body is not a composed body and that the form of
the body is something separate that nevertheless is the mover of
the heavenly body. But this is an absurd position, for it implies
in potentia ad formam corruptibilis corporis. Et cum non habeat earn in actu, erit simul sub
forma et privatione; quia carentia formae in eo quod est in potentia ad formam, est privatio.
Haec autem dispositio est corruptibilis corporis. Impossibile ergo est quod corporis
corruptibilis et incorruptibilis per naturam sit una materia" (STh I, q. 66, a. 2 [Ottawa:
Dominican College, 1941], 404a).
65 "'Nee tamen dicendum est, ut Averroes fingit, quod ipsum corpus caeleste sit materia
caeli, ens in potentia ad ubi et non ad esse; et forma eius est substantia separata quae unitur
ei ut motor. Quia impossibile est ponere aliquod ens actu, quin vel ipsum totum sit actus et
forma, vel habeat actum seu formam. Remota ergo per intellectum substantia separata quae
ponitur motor, si corpus caeleste non est habens formam, quod est componi ex forma et
subiecto formae, sequitur quod sit totum forma et actus. Omne autem tale est intellectum in
actu; quod de corpore caelesti dici non potest, cum sit sensibile. Relinquitur ergo quod materia
corporis caelestis, secundum se considerata, non est in potentia nisi ad formam quam habet.
Nee refert ad propositum quaecumque sit illa, sive anima sive aliquid aliud. Unde illa forma
sic perficit illam materiam, quod nullo modo in ea remanet potentia ad esse, sed ad ubi
tantum, ut Aristoteles dicit. Et sic non est eadem materia corporis caelestis et elementorum,
nisi secundum analogiam, secundum quod conveniunt in ratione potentiae" (STh I, q. 66, a.
2 [Ottawa 404a-b]).

AQUINAS ON CELESTIAL MATIER

457

that something could be actually existent and not be or have form.
Form, however, is the principle of actuality, which means that
whatever is actual must either be form or have form. The heavenly
bodies cannot be pure forms, for pure forms are not perceptible,
but heavenly bodies are. The heavenly bodies must, therefore,
have forms. To have a form means that the capacity or potency of
the substance is actualized by form. The capacity or potency for
form, in turn, is what is meant by matter. Thus, the heavenly
bodies must be composites of matter and form. That which is in
potency to form is matter without any form, or prime matter. But
here is the problem. The potency of the prime matter of the
heavenly bodies must be in potency to one form only, for if it
were in potency to other forms, the heavenly body would be
corruptible. Since we know that the heavenly bodies are
incorruptible, we know that the potency of their prime matter is
a potency only for the form to which it is united and to no other
form. This, however, means that the prime matter of the heavenly
bodies is not the same as the prime matter of the earthly bodies.
There are, then, two kinds of prime matter.
One misunderstanding should be avoided. It is, of course,
misleading to speak of "two kinds" of prime matter, as though
"matter" were a genus with two species, corruptible and
incorruptible. This way of speaking would be wrong because it
would import a notion of form into the very meaning of matter.
If matter were a genus, in order to distinguish one "kind" of
matter from another, each kind would have to be formally
distinct. But to say that they are formally distinct is to suppose
that there is a form by which they are distinct. Prime matter, of
course, is understood to be pure potency. Since Thomas is
committed to the position that there is only one substantial form
in every substance, he is also committed to the pure potentiality
of prime matter. We cannot pretend to distinguish "kinds" of
prime matter by virtue of some formal determination. Rather,
when Thomas claims that the matter of the heavenly bodies is of
a different sort from that down here, he means that the two
matters are simply different beyond any possible common genus.

STEVEN BALDNER

458

The position that Thomas gives in the Summa Theologiae,
then, is the following. The prime matter of earthly bodies is an
omnipotentiality for substantial form. No one substantial form, no
matter how perfect, can satisfy that potentiality. Hence, if the
heavenly bodies are incorruptible, they can only be so because the
prime matter in them is different. Heavenly prime matter does not
have an omnipotentiality but rather a potency for one form only.
This one form to which the prime matter is in potency can satisfy
the potency of prime matter and therefore remove from it any
privation to other substantial forms. It can do so precisely because
the matter is ordained to it and to no other form.
Somewhat later in his life, when he wrote his commentary on
Aristotle's De caelo (1272-73) 66 and De substantiis separatis
(1271), 67 Thomas explains the incorruptibility of the heavenly
bodies with an emphasis that is considerably different from that
which is found in the Summa Theologiae. In these later works, he
lays stress on the fact that it is the form of the heavenly bodies
that makes them incorruptible. There is a change of emphasis
from matter to form, and this change is indicative, I think, of a
change in doctrine.
In lecture 6 of book 1 of the commentary on De caelo 1.3,
Thomas comments on Aristotle's argument for the incorruptibility
of the heavenly bodies. 68 From the fact that only circular motion
is found in the heavens and that there is no motion that is
contrary to circular motion, we infer that there is nothing
contrary to the heavenly bodies. If there is nothing contrary to the
heavenly bodies, we can infer that there is no generation and
corruption there, for generation and corruption is always from
one contrary to another. The heavenly bodies, therefore, are
incorruptible.
Against this Aristotelian argument, John Philoponus, Thomas
reports, has objected with three arguments, the second and third
of which are relevant to our problem. Philoponus's second
argument is that all heavenly bodies are finite bodies, and all finite
66 Torrell, St. Thomas Aquinas, 344.
67 Ibid., 350.
68

Aristotle, De caelo 1.3.270a12-22.

AQUINAS ON CELESTIALMATIER

459

bodies have finite power. But whatever has finite power can only
exist for a finite amount of time. Therefore, Philoponus
concludes, the heavenly bodies are temporally finite and hence
corruptible. 69
We need not pay attention to Thomas's own answer to this
objection, but we will look at Thomas's rejection of Averroes'
mistaken attempt to answer this objection. Because of the sort of
argument that Philoponus has given, Averroes mistakenly claimed
that the heavenly body does not have a power (potentia) for
existing but only a power (virtus sive potentia) for local motion. 70
Hence, on Averroes' account, the heavenly body would not have
its own power of existing-that is, its own form-and hence the
form of the heavenly bodies must be separate. 71 Averroes,
however, was deceived,
because he thought that the power of existing belongs only to the passive
potency, which is the potency of matter, whereas in fact it belongs more [or
"rather"-magis] to the potency of form, because each thing is through its form.
Hence, any thing has being to the extent and for the length of time that
corresponds to the power of its form. And so it is that there is a power of being
forever, not only in the heavenly bodies but also in the separate substances. 72

A thing is, Thomas tells us, through its form; this is true for
material things and for immaterial things. Form makes the thing
to be the kind of thing that it is, and the kind of thing is either
69 "Omnis virtus corporis finiti est finita, ut probatur in VIlI Physic.: sed virtus finita non
potest se extendere ad durationem infinitam (unde per virtutem finitam non potest aliquid
moveri tempore infinite, ut ibidem probatur): ergo corpus caeleste non habet virtutem ut sit
infinitum tempore" (In Aristotelis libros De caelo et mundo, ed P.M. Maggiolo [Rome:
Marietti, 1965] lib. 1,lect. 6, 11 59 (pp. 29-30).
70 "Quod autem obiicit [Philoponus] virtutem corporis caelestis esse finitam, solvit
Averroes dicendo quod in corpore caelesti est virtus sive potentia ad mo tum secundum locum,
non est autem virtus sive potentia ad esse, neque finita neque infinita" (I De caelo, lect. 6, 11
62 [Maggiolo, ed., 30]).
71 This sentence is my completion of Thomas's argument.
72 "Fuit autem [Averroes] deceptus per hoc quod existimavit virtutem essendi pertinere
solum ad potentiam passivam, quae est potentia materiae; cum magis pertineat ad potentiam
formae, quia unumquodque est per suam formam. Unde tantum et tamdiu habet unaquaeque
res de esse, quanta est virtus formae eius. Et sic non solum in corporibus caelestibus, sed etiam
in substantiis separatis est virtus essendi semper" (I De caelo, lect. 6, 11 62 [Maggiolo, ed., 30)).

460

STEVEN BALDNER

corruptible or incorruptible. The role of matter here is either not
so important or, as I think, is not important at all.
Philoponus's third argument is that any natural body must have
matter and privation, and wherever there is matter and privation
there must be a potency to corruption. If the matter of the
heavens were different from that down here (thus explaining the
incorruptibility of the heavens), such a difference in matter could
only come about because there was some sort of composition in
the matter. Matter would have to be composed of what is
common to matter and what makes matter different in the
in the incorruptible cases.73
corruptible
Thomas answers this objection by arguing that, whereas the
objector had implied that matter and privation are necessarily
correlative, the key to seeing that a heavenly body does not have
privation is in the form of that body.
It is not necessary that the subject or matter [of the heavenly body] have
privation, because privation is nothing other than an absence of a form that
could naturally belong to the thing. To this matter or subject [that is, of the
heavenly body], however, no other form could naturally belong, because its own
form completely satisfies the potentiality of matter, since it is a kind of total and
universal perfection. This is clear from the fact that the [heavenly body's] active
power is universal, not limited like the power of earthly bodies, whose forms,
since they exist in a limited way, cannot completely satisfy the entire potentiality
of matter. Hence, [in an earthly body] the privation of some other form that it
could naturally acquire remains in the matter along with the form [that it does
have]. 74

73 "In omni corpore naturali est materia et privatio, ut patet ex I Physic.: sed ubicumque
est materia cum privatione, est potentia ad corruptionem: ergo corpus caeleste est corruptible.
Si quis autem dicat quod non est eadem materia caelestium corporum et inferiorum, obiicit
in contrarium: quia secundum hoc oporteret quod materia esset composita, ex eo quod facit
diversitatem inter materias" (I De caelo, lect. 6, ' 60 [Maggiolo, ed., 30]).
74 "Non tam en oportet quod istud subiectum vel materia habeat privationem: quia privatio
nihil aliud est quam absentia formae quae est nata inesse, huic autem materiae vel subiecto non
est nata inesse alia forma, sed forma sua replet totam potentialitatem materiae, cum sit
quaedam totalis et universalis perfectio. Quod patet ex hoc, quod virtus activa eius est
universalis, non particularis sicut virtus inferiorum corporum; quorum formae, tanquam
particulares existentes, non possunt replere totam potentialitatem materiae; unde simul cum
una fonna remanet in materia privatio formae alterius, quae est apta nata inesse" (I De caelo,
cap. 3, lect. 6, ' 63 [Maggiolo, ed., 30)).

AQUINAS ON CELESTIALMATIER

461

Thomas here seems to be affirming what he denied in the Summa
Theologiae: that a more perfect, more universal, more powerful
form could completely satisfy the potentiality of matter. The
problem raised by Philoponus is about privation: does a material
substance always have privation? No, says Thomas here, because
some material substances have forms that are sufficiently eminent
to disallow any privation. If by virtue of form the heavenly body
has no privation of other forms, then it is by virtue of form that
the heavenly body is incorruptible. The point of the objection had
been that it is by virtue of matter that the heavenly body is
corruptible; Thomas's response is that it is by virtue of the form
that the heavenly body is incorruptible.
Thomas gives the heavenly bodies' inalterability as another
instance of their lack of privation (for there is in the heavenly
bodies only a privation of place), and then he comments on the
matter of the heavenly bodies.
From which it follows that the matter of the heavenly body is different from that
of the earthly bodies, not because there is some composition [in the matter], as
Philoponus thought, but through the relation [habitudo] of [matter] to different
forms, one of which is total and the other is partial. In this way the potentialities
[of matter] are diversified by the diversity of actualities to which they are
related. 75

Matter in itself, prime matter, is unknowable. It is knowable not
itself but only in relation to form. The word "relation," of course,
is out of place, because matter is not related to form, as though
matter and form were two things. Matter is different, however,
according to the different forms that we recognize. If the form is
the form of an incorruptible substance, we have incorruptible
matter; if the form is the form of a corruptible substance, we have
corruptible matter. Thomas agrees with Philoponus that there
cannot be any composition in matter, but if so, how then to
75 "Ex quo patet quod materia caelestis corporis est alia et alterius rationis a materia
inferiorum corporum, non quidem per aliquam compositionem, sicut Philoponus existimavit;
sed per habitudinem ad diversas formas, quarum una est totalis et alia partialis: sic enim
potentiae diversificantur secundum cliversitatemactuum ad quos sunt" (IDe caelo, cap. 3, lect.
6, 11 63 [Maggiolo, ed., 31]).

462

STEVEN BALDNER

explain that matter is different? We cannot, so to speak, add some
additional intelligible note to matter to make it different in one
case from what it is in another case. If matter is different, it is
because of matter's "relation" to form. But that "relation" (habitudo) cannot be something in matter, for that would indicate
composition-and that is what Thomas and Philoponus are agreed
in rejecting-and hence it must be the fact that matter in one
instance is related to, or united to, an incorruptible form, but
matter in another instance is related to, or united to, a corruptible
form. This would mean that the diversity of matter between the
heavenly bodies and earthly bodies is attributable to form.
The passage I have just quoted and commented upon is the
crucial one. Can it be interpreted in a different way? I think that
one could understand the habitudo differently from the way that
I have understood (or perhaps misunderstood) it. One could say
that by habitudo Thomas means the inherent ordination of prime
matter: one sort of prime matter is ordained to an incorruptible
form and another sort of prime matter is ordained to a corruptible
form. In other words, it could be interpreted in accord with the
text from the Summa Theologiae.
I do not, however, think that this is the best interpretation of
this text because of Thomas's specification, again, that the habitudo in question is precisely one that is either to a total form or
to a partial form. Potencies, Thomas points out, are diversified by
the acts toward which they are directed. The reason for diversity
seems to be on the side of the form and not on the side of the
matter. When we find a diversity of matter it is because of a
diversity of form, not the other way around. And in that case,
"diversity of matter" means a diversity of secondary matter, not
a diversity of prime matter. Further, the point Thomas is trying to
make in this passage is that the form of the heavenly body is
different from that of the earthly; the heavenly body's form is
total, not partial. It is the fact that the matter of the heavenly
body is united to a "total" form that makes it incorruptible, unlike
the matter of early bodies that are united to "partial" forms.
The interpretation I have given to the text in De caelo is
confirmed in the contemporaneous De substantiis separatis. In

AQUINAS ON CELESTIALMATTER

463

that work, when he is responding to the position of Avicebron,
Thomas explains that there are different levels of creatures. Some
participate in being more fully than others. Those that most
perfectly participate in being have no principle within them that
is "being in potency only" (non habent in se ipsis aliquid quod sit
ens in potentia solum). 76 These, of course, are the "separate
substances," substances that are separate from matter, that is,
angels or celestial movers, which are immaterial forms. A second
level of creatures is the level of those that do have matter, and the
matter is essentially a "being in potency only" (ens in potentia
tantum). 77 The entire potentiality of this matter is completed by
form, so that there remains in such beings no potency for some
other form. Such beings-the heavenly bodies-are, therefore,
incorruptible. Just as the body of a planet or star is so subject to
its fixed quantity and quality that no alteration is possible, so also
the matter of such a body is so subject to substantial form that no
corruption is possible. Third, there are corruptible substances,
which also have matter that is "being in potency only" (ens in
potentia tantum). 78 The potency of matter in this third sort of
76 "Illae enim substantiae quae perfectissime esse participant non habent in se ipsis aliquid
quod sit ens in potentia solum, unde immateriales substantiae dicuntur" (De substantiis
separatis,c. 8, in Sancti Thomae de Aquino Opera omnia iussu LeonisXIII P.M. edita, vol. 40,
part D [Rome: Sancta Sabina, 1969] 54:118-21).
77 "Sub his vero sunt substantiae quae, etsi in se ipsis huiusmodi materiam habeant quae
secundum sui essentiam est ens in potentia tantum, tota tamen earum potentialitas completur
per formam ut in eis non remaneat potentia ad aliam formam, unde et incorruptibiles sunt,
sicut caelestia corpora; quae necesse est ex materia et forma composita esse. Manifestum est
enim ea actu existere, aliquin motus subiecta esse non possent aut sensui subiacere aut alicuius
actionis esse principium; nullum autem eorum est forma tantum quia, si essent formae absque
materia, essent substantiae intelligibiles actu simul et intelligentes secundum se ipsas: quod esse
non potest, cum intelligere actus corporis esse non posit, ut probatur in libro De anima.
Relinquitur ergo quod sunt quidem ex materia et forma composita; sed sicut illud corpus ita
est huic magnitudini et figurae determinatae subiectum quod tamen non est in potentia ad
aliam magnitudinem vel figuram, ita caelestium corporum materia ita est huic formae subiecta
quod non est in potentia ad aliam formam" (De substantiis separatis, c. 8 [Leonine 54:12244]).
78 "Sub his vero substantiis est tertius substantiarum gradus, scilicet corruptibilium
corporum quae in se ipsis huiusmodi materiam habent quae est ens in potentia tantum; nee
tamen tota potentialitas huiusmodi materiae completur per formam unam cui subicitur quin
remaneat adhuc in potentia ad alias formas" (De substantiis separatis,c. 8 [Leonine ed., 5455: 145-51]).

464

STEVEN BALDNER

substance is not entirely completed by the form to which it is
united, and for that reason this kind of substance is corruptible.
In this text, then, Thomas compares separate substances,
incorruptible material substances, and corruptible material
substances with respect to the same principle: matter understood
as "being in potency only." That is, he is comparing the three
sorts of substance with respect to prime matter, for prime matter
is "being in potency only." There is no prime matter in the
separated substances, but there is prime matter in both the
heavenly bodies and the earthly bodies. The only difference
between the heavenly and the earthly bodies is the difference that
comes from form. In the one case, the form so completes the
potency of prime matter that there is no potency for some other
form; in the other case, the form does not so complete the
potency of prime matter and hence there remains the potency for
other forms. There is no doctrine of two prime matters. It is the
form and the form alone that accounts for the incorruptibility of
the heavenly bodies.
IV. CONCLUSION

Let us summarize what we have found. Early in his academic
career (in the 1250s), under the influence of Averroes and Albert,
Thomas endorsed, although without much elaboration, an
Averroistic view of the heavenly bodies. This view is that the
heavenly bodies are not substantially composed of form and
matter. Rather, the heavenly bodies are simple units of matter that
are moved by separate movers. After this early period, Thomas
stoutly rejects the Averroist position, affirming always that no
created substance can be actual except by form. A created
substance either is a form (as is a separate substance) or it has a
form (as does a material substance). Since the heavenly bodies are
obviously material substances (for they are visible), they must be
composites of form and matter. How, then, are they
incorruptible?

AQUINAS ON CELESTIALMATIER

465

Here there are two possible stories. The first is that Thomas
recognizes that the prime matter of the heavenly bodies must be
a different sort of prime matter from that found in corruptible
substances. The prime matter of a heavenly body is uniquely
ordained to the form that it has, and because it is so ordained, its
form naturally satisfies the entire potency of this matter. Such
prime matter would not have the pure potentiality of earthly
prime matter but would have a limited potentiality for one form
only. The one form toward which it is in potency would have the
ability to terminate that potency in such a way that there would
be no privation of other substantial forms. If there is no privation,
there is no corruptibility. This is the position expressed in the
Summa Theologiae.
The second story is that of Thomas's later works, the
commentary on De caelo and De substantiis separatis. In these
two works Thomas attributes the incorruptibility of the heavenly
bodies to the form. It is because the form of the heavenly body
has a universal or perfect power that it is able to satisfy the
potency of prime matter. There are not two kinds of prime matter
but rather two very different kinds of substantial form, the one
limited and partial, the other unlimited and universal.
The reason for the two stories would be that Thomas saw more
clearly the implications of the incorruptibility of the heavenly
bodies. He knew that he had to account for the heavenly bodies
as composed bodies, but the principles of substantial
composition-form and matter-are principles given in the first
instance to explain substantial change. Thomas earlier considers
the matter as the principle of incorruptibility, but comes later to
regard the form as the principle of incorruptibility. Such is the
picture of Thomas' s development on this topic, as I understand it.
There is, however, another possible reading of the texts,
according to which there are not really two stories, but only one.
There are not two stories because Thomas always (at least in his
mature period) regarded both matter and form as the principles
of the incorruptibility of the heavenly bodies. The difference
between a text like that in the Summa Theologiae and that in De

466

STEVEN BALDNER

caelo is a difference in emphasis only, not a difference in doctrine.
The earlier text emphasizes matter, but does not exclude the role
of form, and the later text emphasizes the role of form, but does
not exclude the role of matter. Hence Thomas's mature position
can be given as one story, not two.
I cannot decisively reject this second reading of the texts. It can
plausibly be defended from the texts and it has the merit of
making Thomas more consistent in his maturity. As I have tried
to indicate, I think that the texts are better interpreted in my way,
and I think that my interpretation represents a very plausible
account of Thomas's intellectual development. The texts themselves, however, are sufficiently ambiguous to allow both
interpretations.
The interpretation I reject requires that both matter and form
play a role in accounting for the incorruptibility of the heavenly
bodies. Matter must be uniquely ordained to a certain form, and
the form must so satisfy the potency of matter that there is no
privation of other forms. It seems to me, however, that there are
two problems philosophically with this interpretation. First, I find
it difficult to understand how prime matter can remain
indeterminate and yet of itself have an ordination to this form
rather than that. It seems to me that if prime matter is understood
not as pure potency but as some sort of restricted potency, then
it is no longer prime matter, but it is matter that has some formal
determination. Something must do the restricting; something must
make the prime matter to be a restricted not a pure potency. But
in such a case, we are no longer dealing with prime matter.
Second, if it is true that prime matter in the heavenly bodies has
a restricted potency to one form only, then I do not see how form
has any role to play at all in accounting for incorruptibility. If the
matter can by its own nature be united to one form only, then, of
course, the form satisfies the entire potency of that prime matter,
but that fact is really attributable to the matter. There would be
no need to talk, as Thomas does, about "universal" or "more
perfect" forms, as opposed to "particular" or less perfect forms,
that are able to satisfy the potency of matter. Thomas's

AQUINAS ON CELESTIALMATIER

467

justification of the role of form in De caelo and De substantiis
separatis would not seem to have much point, if he were indeed
maintaining a doctrine of two kinds of prime matter.
Aristotelian principles of form and matter are introduced,
fundamentally, to account for change, both substantial and
accidental. These principles are under some strain when they are
used to explain material substances that are held not to be liable
to substantial change. It is good news rather than not for
Aristotelian principles and Thomistic philosophy that the
incorruptible heavens are no longer a part of the cosmology we
are trying to explain. 79

79 I wish to express my deep gratitude to three able scholars who contributed to this essay
by providing critical commentary on earlier drafts: Prof. Christopher Byrne, Prof. William
Carroll, and Prof. Christopher Decaen.

BOOK REVIEWS
Philosophy of Being: A &constructive Essay in Metaphysics. By OLIVA
BLANCHETIE. Washington, D.C.: The Catholic University of America
Press, 2003. Pp. xxiii + 563. $59.95 (cloth), $39.95 (paper). ISBN 08132-1095-X (cloth), 0-8132-1096-8 (paper).
Metaphysics, as many recognize these days, has fallen on hard times.
Through the course of modern philosophy, it has lost its vital contact with reality
and disappeared into the abstractions of "ontology." In this work, Oliva
Blanchette takes up the challenge of renewing metaphysical inquiry in the third
millennium by deconstructing modern ontology and reconstructing thought as
it relates to the concrete. This can be accomplished, he believes, only by
returning to a "more ancient view" of this science. He sees his book, accordingly,
as "an effort at critical reconstruction in the philosophy of being or metaphysics
as understood in the ancient sense." He begins with Heidegger, "who has done
more than anyone else in our time to bring the question of being back to the
forefront of philosophy," but also enlists the help of Plato, Aristotle, and
Aguinas, whom he names "the last great metaphysician in the ancient mode"
(xiv-xv).
Blanchette describes this massive work engagingly as a "play" or "dialog"
between the author and the reader in which the reader must take an active part
since "one does not do metaphysics except on one's own intellectual initiative"
and through the exercise of "one's own critical reflection" (xvi). The play has six
parts, dealing with the question, meaning, properties, structure, communication,
and summit of being.
Part I takes up the subject and method of metaphysics. Rejecting the
essentialism of Suarez, Wolff, Kant, and Heidegger, Blanchette argues that "only
being taken precisely as being can be taken as the proper subject of metaphysics"
(25-26). He begins by affirming that "knowing is of being" and then reviews the
different ways of knowing or different sciences to arrive at "the idea of a first
kind of knowing." Finally he asks "how the subject of investigation for this first
kind of knowing or this first philosophy is tQ be conceived" (26). This does not
involve any judgment about material or immaterial being since being as it
"presents itself in the very first act of knowing," in the "primordial conception
of being," is "neither material nor immaterial, but simply being, including both,
if the two are to be distinguished" (27-28).

469

470

BOOK REVIEWS

In describing the method of metaphysics, Blanchette analyzes the act of
intelligence into "understanding" (simple apprehension) and "critical reflection"
(judgment). It is in the exercise of judgment that being presents itself to our
knowing, and metaphysics begins "in the reflection that occurs in any serious
exercise of judgment" (45, 70). Metaphysics is "the attempt to formulate this
reflective presence of being in an exercise of judgment that transcends the
judgments of direct experience" (74). There is no gap between knowing and
being since being is not some "thing in itself" (Kant), but is "simply what is
known when knowing takes place" (76). Since being is given in the act or "actual
exercise" of judgment, the task of metaphysics is to penetrate the exercise of
judgment and so "elaborate the full meaning of being both conceptually and in
act" (77).
In the second part of his essay, Blanchette considers the meaning of being.
The notion of being involves three aspects: haecceity (this-ness), quiddity, and
the act of being (115). Since being is not a category, but a concept that
transcends the categories of Aristotle, it has its own transcendental order which
can only be expressed through the use of analogy (117). In his discussion of
analogy and its distinction from univocity and equivocation, Blanchette provides
some helpful insights into the tendency (or even the duty) of the particular
sciences to treat their subject matter univocally (a tendency, he notes, which
opens the way to reductionism and which, we might add, often plagues the
contemporary dialogue between empirical science and theology) (122, 128).
Analogy is a key element "in the reconstruction of a metaphysics that is true
to the question of being in its difference and in its diversity" (120). For being is
not to be seen as "some generic category in which all beings could equally fit,"
but rather as "an order of different beings unified conceptually by a reference to
one" (119). Using Aquinas's discussion from the Commentary on the Sentences
(I Sent., d. 19, q. 5, a. 2, ad 1), Blanchette shows how both differences and
similarities of meaning are built into the analogous term. He departs from
Aquinas and Aristotle, however, in his argument that the "one" or the "prime
analogate" for being is neither substance (Aristotle, Metaphys. 1003 b5-10) nor
God (Aquinas, STh I, q. 13, aa. 5-6), but rather the human being (130-39). In
this, he notes that he is following Heidegger and also intentionally beginning
with what is better known to us rather than better known in itself. By limiting
being to the way "it presents itself in experience," however, he does seem in
danger (despite his arguments to the contrary) of limiting the metaphysical
enterprise to the realm of human experience: "Only with a primary analogate
properly located in the human being can we proceed to a metaphysical account
of the differences of being as given in experience. For being can be understood
in the full analogy of its difference only through reference to this one-pros
touto hen" (138-40).
In part 3, Blanchette gives a careful and nuanced discussion of the transcendental modes of being, including not only being as one, true, and good, but also
being as active and being as universe. Here again, "it is from human being and
in relation to human being that we come to understand all of being." Being is

BOOK REVIEWS

471

understood as true and good not in relation to divine being, but "from the
standpoint of our own intelligence and will" (194). With this starting point, it
is not clear that his attempt "to think of being in its transcendental openness,
even to the point of infinity" really escapes the limits of human thought and
experience in which the discussion is framed (195-96). "Truth and goodness are
properties of being precisely in this relation of all being or beings to human
being as both intelligence and appetite." Though admittedly not itself "the
summit of being or the norm of all truth and goodness," human being remains
"the being around which our conception of being as given in experience is
ordered" (232-33).
Blanchette's treatment of the structure of being in part 4 begins with a
discussion of the differences in being and the distinction between being and
becoming and then goes on to consider substance, matter (potency), form (act),
·the act of being, and the real distinction between essence and the act of being.
In distinguishing being from becoming, he uses the "unsurpassed" (249)
arguments of Aristotle to negotiate between Parmenides and Heraclitus (and
Whitehead). He also points out some helpful similarities between Aristotle's
principles of change and certain features of modern science (255). His discussion
of matter provides a useful corrective to the tendency to reductionism in modern
science (286) and brings out an often overlooked "dynamic" aspect in the
passivity of prime matter (294, 297).
In part 5, Blanchette retrieves the notion of final cause which is generally
neglected by modern science and puts the notion of efficient cause into a
metaphysical rather than merely mechanistic context. Final cause is explained in
relation to formal cause, and efficient cause in relation to material cause. Here,
accepting human being as the primary analogate of being is useful since it
immediately allows the notion of intentionality (evidently a characteristic of
human activity) to enter into the broader discussion of causality. Final causality
explains why different beings tend to interact, and efficient causality explains
how they interact in the communication of being (406). Blanchette's careful
explanation of how beings constitute a "universe" only through their dynamic
interactions can serve as a corrective to those who would characterize the world
of Aristotle or Aquinas as "static."
The final part of the book takes up the question of God as the summit of
being. Rather than starting with a particular being or a particular relationship
among beings as Aquinas does in his five ways (STh I, q. 2, a. 3), Blanchette
begins with a question about the cause of all being "in its commonality" (479).
He asserts that "[u]nless we first raise the question of being as being, we cannot
in any way raise the question of a universal cause of being as being" and asserts
that even "when one agrees to the conclusion that God exists, say, in faith, if
there is not metaphysical understanding, it can only be a non sequitur open to
all sorts of misunderstandings" (493-94). Although he employs Aquinas's five
ways to establish the existence of God, he tends to ground them in human
experience rather than reality. He asserts, for instance, that Aquinas begins his
first three ways of showing that God exists with "different aspects of being as

472

BOOK REVIEWS

given in experience" (505). A careful reading of Aquinas, however, shows that
he begins not with being under the aspect of experience, but with being as such:
"It is certain and evident to our senses, that in the world some things are in
motion" (STh I, q. 2, a. 3), not that some things are experienced as being in
motion. Blanchette's example of a pool player who hits a ball which sinks
another ball is a helpful illustration of a cause that causes the motion of another,
but it does not seem an adequate representation of the "per se subordinated
moving causes" required in the first way (508), where the last in the series
cannot act unless the first is presently active.
In his discussion of transcendence and immanence, Blanchette is concerned
to show the limits of philosophy. While theology may have God as its subject,
metaphysics attains God only as the principle of its subject. He clearly explains
that philosophy is not able to know what God is, but then suggests that theology
is capable of such knowledge: "Let us think back to the notion of theology we
have already referred to as the science that would have God as the subject of its
consideration. We have argued that metaphysics, by itself as the science of being
as being, cannot give rise to any kind of positive theology of this kind, since that
would have to presuppose that it can give us an account of what God is as God,
which, as we have also argued metaphysics cannot do" (551). For Aquinas,
however, even theology cannot give an account of what God is: "By revelation
of grace in this life we cannot know of God what he is," and "[n]either a
Catholic nor a pagan knows the very nature of God as it is in itself." (STh I, q.
12, a. 13, ad 1; STh I, q. 13, a. 10, ad 5).
Blanchette has produced a book of colossal breadth and depth of erudition,
and the criticisms raised here in no way diminish that accomplishment. It is a
work that solidly establishes the metaphysical enterprise at the beginning of the
third millennium. All contemporary philosophers will surely find profit in its
careful study.

MICHAEL].DODDS, 0.P.
Dominican School of Philosophy and Theology
Berkeley, California

Restoring Faith in Reason. Edited by LAURENCE PAUL HEMMING and SUSAN
FRANK PARSONS. London: SCM Press, 2002. Pp. 320. $24.95 (paper).
ISBN 0334028418.
The bulk of this book (pp. 1-173) consists of the Latin text of the 1998
encyclical letter Fides et ratio, together with a facing-page English translation.
This is followed by a commentary on the encyclical by James McEvoy (175-98),
and then by seven essays on various aspects and implications of the letter. The

BOOK REVIEWS

473

essays, by Wayne J. Hankey, Laurence Paul Hemming, Eilert Herms, Nicholas
Lash, Aristotle Papanikolaou, Robert Sokolowski, and Janet Soskice, are mostly
by Catholic philosophers and theologians, but Orthodox (Papanikolaou) and
Protestant (Herms) Christianity are represented as well. There are, in addition,
name- and subject-indexes to the encyclical and the interpretive materials. The
volume is presented by the editors as "the first in what we hope will be a number
of studies which, in different ways, and from a variety of perspectives, will pay
generous heed to the questions which Fides et ratio has raised" (xii).
The latin text provided is the same (save one or two misprints) as the official
text published in the Acta apostolicaesedis; but the English translation, made by
Anthony Meredith and Hemming (with, the acknowledgments suggest, some
help from others), differs in many minor and some major ways from the official
version, released in 1998 and now available in many printed forms and at the
Vatican website (www.vatican.va). The editors write that they do not intend this
new English version to supplant the official translation (v); but they provide
explanation neither of just why they thought a new English version necessary or
useful, nor of the principles by which it was made. Discussion of these matters
would have been useful and interesting. It is, after all, far from usual to offer new
and competing translations of curial documents, and the fact that Hemming and
Parsons chose to do so must mean that they were dissatisfied with the one
already on offer. They do not here tell us why, though Hemming is on record (in
New Blackfriars)as being dissatisfied with the official translation, and he is not
alone in that.
Most of the differences between the two translations are stylistic, and in
general this new translation is less wooden and more like English than the
official one. It is also more gender-neutral, though not consistently so (in this
matter, as in some others, it reads like the work of a committee in need of a final
going-over from a single hand). But there are also places where the differences
between the two translations are substantive. I have not made a systematic and
complete comparison of the two versions with the latin, but I have taken a few
soundings by looking at interesting passages where the official version had
seemed to me wanting. The new translation usually does better than the old. For
example, in an interesting passage in the third paragraph of §13, on the signs
given by revelation to aid the understanding, the old translation introduces talk
of the mind's autonomy which is quite absent from the latin, and garbles a
number of distinctions that are present in the latin. The new translation gets this
right. There are similar advantages in the new translation's rendering of passages
in §67 and §80. But in §23, the new translation introduces a mistake not present
in the old by seeming to say that our ordinary, limited modes of thought cannot
express themselves, when in fact what they cannot express is revelataesapientiae
altitudo (the trouble is either a typographical error in the English or a misreading
of pronoun reference in the latin).
In general, the new translation is better than the old, and its very existence
usefully presses the question of how approved vernacular versions of curial texts
are made, for it makes it easy to see that the official English version is sometimes

474

BOOK REVIEWS

sufficiently far from the Latin to suggest that perhaps it was not made from the
Latin at all, or at least not from the Latin that constitutes the official text. This
thought gains substance when, as an hour or two's work comparing the official
English version with the official German and French (with these we reach the
limit of this reviewer's linguistic capabilities) versions (something the Vatican's
website makes easy) will show, it is sometimes the case that all three (or two of
the three) are closer to one another than to the Latin. There is a complicated
story here, no doubt, whose details it would be interesting to know, as would be
the linguistic details of the composition of this and other encyclicals. Hemming
and Parsons deserve our thanks for making one part of the difficulty easier to
see. But the very existence of their version also raises questions about textual
authority: their volume carries no imprimatur or nihil obstat, and their version
therefore has no magisterial weight. Nevertheless, its existence surely (and
perhaps interestingly) reduces the magisterial significance of the official version
simply by introducing a competitor.
McEvoy's commentary is a sympathetic analysis, meant not to engage the
encyclical critically or to develop its lines of thought, but rather to clarify its
structure, assumptions, and sources. It does all this well (though without startling
insight), and is especially good on the significance of the exemplary figures
discussed in the encyclical. I was taken aback, though, by the claim that among
the encyclical's nineteenth- and twentieth-century exemplars, "John Henry
Newman is the first ... not unsurprisingly" (194). Is McEvoy really surprised?
This is probably a typographical error, but it might also, I suppose, be a coded
message.
Ha.'lkey's essay, "Practical Considerations about Teaching Philosophy and
Theology Now" (199-205), is an allusive diatribe occasioned by Fides et ratio's
emphasis upon the need for proper philosophical education for priests (and
others). Hankey does not like dogmatic neo-Scholasticism; he likes even less
"theology as post-modern mythopoiesis" (205)-by this he may mean Radical
Orthodoxy; and he would like the skills of reading to be better taught and more
widely known. He mentions, but neither argues for nor fully explains, a view of
the relation between philosophy and theology that may be like that of Fides et
ratio. But it is hard to tell.
Herms's essay, "Objective Truth: Relations between Truth and Revelation
in the Encyclical Fides et ratio" (206-24), provides exactly what its title suggests:
a careful textual analysis of the (various) ways in which veritas is presented and
theorized in Fides et ratio, with special attention to the relations between these
usages and the encyclical's understanding of revelation. Herms's reading is
fundamentally sympathetic: he suggests, rightly, that more is needed than Fides
et ratio provides by way of an epistemology that explains our natural ability to
know the truth-indeed, our flagrans desiderium (§24) for it. The encyclical is
suggestive but not systematic here, and Herms points the way toward what
would have to be done in order to become systematic.
Lash's essay, "Visio Unica et Ordinata Scientiae" (225-36), while fundamentally supportive of the encyclical's plea for a counter to the increasing

BOOK REVIEWS

475

fragmentation of knowledge evident in university settings and public culture,
protests two points: first, the encyclical's tendency to hypostatize 'philosophy'
as though its identity had been stable through history; and second, the
encyclical's insufficient awareness of the depth of the fragmentation of which it
speaks, and the sheer unlikeliness that it can be remedied in the university. Lash
identifies the distinction between faith and reason that informs the encyclical as
excessively dependent upon an "endlessly misleading early modern distinction
between faith and reason" (231). There is certainly something in this, but Lash
is himself insufficiently historical. An Augustinian distinction between what it is
to believe (credere) a truth and what it is to know (cognoscere, etc.) one is certainly not identical with (say) Locke's distinction between faith and knowledge,
but neither is it quite dissimilar. About the second criticism Lash is abundantly
and importantly right: the hope Fides et ratio expresses for unification of
knowledge is best understood as eschatological.
Papanikolaou's essay, "Reasonable Faith and a Trinitarian Logic: Faith and
Reason in Orthodox Theology" (237-55), has more to say about Orthodox
theology than about Fides et ratio. Its central criticism of the latter is that the
encyclical requires assent to a particular philosophy of being as a necessary
condition for assent to the doctrine of the Trinity. This is not, I think, a correct
reading of the encyclical. It would be better to say that what Fides et ratio
requires is some philosophy of universal scope rather than any particular instance
of such; and that the relation of philosophy to theology in the encyclical is not
one of simple priority but rather one of symbiosis. But there is no doubt that
Papanikolaou's criticism does apply to some among the varieties of neoS1.:holasticism,and that there are deep problems with the position he criticizes
even if the encyclical does not hold it.
Scola's essay, "The Integrity of Human Experience: Cultural Dimensions and
Implications of the Encyclical Fides et ratio" (256-76), begins from §§63-71 of
the encyclical, where the relation between culture and cultures is discussed.
Scola's is an extraordinarily wide-ranging essay, dense with literary, historical,
and artistic allusion. It uses Fides et ratio as a springboard for discussion of
analogy, nature, the contemporary civic and political sphere, and so on, and for
the most part does not closely engage the text of the encyclical. It is not
susceptible to easy summary.
Sokolowski's essay, "The Autonomy of Philosophy in Fides et ratio" (27791), written with his customary pellucid elegance, explores the complex view of
the relation between faith and philosophy (which latter he understands as a
particular form of reason) found in the encyclical. What Sokolowski does in this
essay is essentially to apply his own understanding of this matter, worked out at
length in, inter alia, The God of Faith and Reason (1995), to the encyclical as an
exegetical device. This works well if one is persuaded (as I am) of the essential
rightness of Sokolowski's view, but it must be admitted that the encyclical can
be read in other ways, and that the density and ambiguity of some of its
formulations stands in contrast to the sharp, cool elegance of Sokolowski's prose.

476

BOOK REVIEWS

Soskice's essay, "Fides et ratio: The Postmodern Pope" (292-96), provides a
brief and jaunty summary of the encyclical's main goals, with special interest in
its analysis of our cultural malaise, mixed in equal parts of nihilism and despair,
and in its recommendation to return philosophy to its large-scale interests in
fundamental and final questions.
A task for the future, one I have yet to see taken up with the energy it
deserves in the now extensive literature on the encyclical, and certainly absent
from this volume, is discussion of why none of the encyclical's exemplars of
philosophy done well are taken from what is sometimes (misleadingly) called the
Anglo-American analytical tradition. There is a tendency among Catholic
philosophers to think that the only Egyptians who need to be despoiled are the
phenomenological (Husserl, Scheler, Heidegger, and after) and hermeutical
(Levinas, Ricoeur) ones; and that those best equipped to do the despoiling will
always be Thomists of one stripe or another. The pope's own philosophical work
shows that a rich harvest can be reaped in this way. But I suspect that there is
more to be said about what the ratio evident in the work of philosophers (some
Catholic and some very much not) such as Elizabeth Anscombe, Peter Geach,
Michael Dummett, Philippa Foot, Alvin Plantinga, and Peter van lnwagen might
have to offer to the tasks limned by Fides et ratio. It may be that the editors of
this volume, being as I think English, are in a good position to take up that task
in future volumes in this series.
This is, then, a mixed bag, as are all such collections. Some of the individual
contributions provide deep and useful insight into the encyclical and the issues
it propounds. Yet the volume's truly distinctive {if somewhat puzzling)
is the new translation it provides.
PAUL}. GRIFFITHS

University of Illinois at Chicago
Chicago, Illinois

God, Evil, and Innocent Suffering: A Theological Reflection. By JOHN E. THIEL.
New York: Crossroad Publishing Company, 2002. Pp. 192. $24.95
(paper). ISBN 0-8245-1928-0.

The modern project known as "theodicy" has been with us a long time-at
least since Leibniz's book of that title published in 1710. The theological appeal
of this project is undeniable. No religious person wants to believe that his or her
God is a monster who sends planes crashing into buildings or wills a child's
death by cancer. On the other hand, theodicy's critics-and they have been
many-have wondered if the price to be paid is too great. Is not the God of
theodicy a rationalized deity, constructed according to human needs and
purposes? Don't pious attempts to make sense of evil tend toward rendering it

BOOK REVIEWS

477

tolerable? It is understandable if some prefer to endure the mystery of evil in
faith, rather than offering blasphemous explanations for its existence.
John Thiel's God, Evil, and Innocent Suffering is one long, determined effort
to resist the temptations of theodicy. Thiel seeks to offer a theological account
of evil and suffering that "move[s] within the language of scripture and
tradition," its rationality governed by "the most basic Christian claims of faith"
(3). At the same time, Thiel is not entirely happy with the ways in which the
classical tradition has approached these issues. His book seeks to chart an
alternative course within the tradition that can better address the mystery of evil.
The key term of his inquiry is found in the book's title: innocent suffering.
Thiel argues that for much of the tradition, there is really no such thing as
innocent suffering. Augustine believed that most human suffering could be
accounted for on the basis of the Fall. This theological answer reflects a deep
religious urge to see God as just and loving. If innocent suffering exists, then
God is indeed a monster; so if God has the character we attribute to him, then
suffering cannot be innocent. As Thiel rightly says, "the denial of innocent
suffering lets the Christian God be the Christian God" (12). But this orthodox
explanation does not sit well with our experience. We know there is innocent
suffering in the world. From the Book of Job to Eli Wiesel's The Trial of God,
the protest rises that some suffer all out of proportion to their supposed guilt.
The usual example brought forward in modernity is the suffering of
children-those we tellingly refer to as "innocents."
Yet it is not only the Augustinian tradition that has problems acknowledging
innocent suffering. Thiel argues that modern theologians who construe suffering
as educative, such as John Hick or Richard Swinburne, likewise evade the issue.
While Hick certainly does not think people deserve to suffer, he does see them
as responsible for "transforming" suffering into meaning. Here is the familiar
free-will defense: a world of suffering is better than a world without, because it
is better to be free than to be determined. Thiel correctly sees a problem here.
Doesn't Hick's view reduce horrendous evil to an opportunity for personal
growth? A different version of this problem is found in process theology, whose
finite God is capable of turning the caprices of nature and history into a joyous
future. Here, too, scandal dissolves within a scheme of evolutionary progress.
If both modern and premodern approaches to suffering fail, what is the
alternative? Thiel's own constructive proposal seeks to hold together three
assumptions: (1) traditional Christian beliefs in God's absolute goodness,
omnipotence, and omnipresence are to be affirmed; (2) innocent suffering is real,
and must not be softened in an attempt to render it "meaningful"; and (3) God
neither permits nor wills evil in any form. This third point is crucial. More
specifically, Thiel's account seeks to "reject the view that God is the cause of
suffering either by permitting the evil victimization of some by others, or by
willing suffering through natural means, including the limitations of the human
condition such as disease, old age, and death. Indeed, I shall argue that God
neither permits, nor wills, nor causes any kind of suffering and death" (59).
Against what he sees as the tradition's tendency to make God an agent of
death, Thiel simply denies that this is so. Key texts within the canon portray God

478

BOOK REVIEWS

as the author of life, and therefore as the enemy and overcomer of death ("he
will swallow up death forever" [Isa 25 :7]; "Death will be no more" [Rev 21:4]}.
A consistent understanding God as life-giver means that there is no "place" for
suffering, even in the sense of God's permissive will. Death and suffering are
simply what God resists with every power at his disposal. Thiel bolsters his case
by highlighting the biblical theme of promise and by appealing to the Christus
victor motif in the Fathers. Far more so than Anselm, the "dramatic" theory of
atonement allows us to see God's relation to death as one of sheer opposition.
Thiel's penultimate chapter seeks to find a way of affirming the force of the
doctrine of original sin-humanity's radical need for grace-while denying one
of its corollaries: death as divine retribution. With God removed as agent of
suffering and death, we are left with the suffering that innocents experience at
the hands of others and from what Thiel calls "precedent evil" (his term for
"natural" evil). God does not cause, but is present to our suffering. The final
chapter attempts to rethink Christology and discipleship in light of innocent
suffering. Like many contemporary theologians, Thiel places the resurrection
rather than the cross at the center of God's purposes. Christ's suffering and death
are not the means by which God saves the world, but show us "God's solidarity
with humanity in the midst of its own innocent suffering. Jesus' suffering reveals
God's judgment on death's dehumanizing power" (163).
My major worry about the book is whether the central notion of innocent
suffering is made to do far too much work. On the one hand, Thiel is surely right
to criticize the traditional equation between suffering and divine retribution. The
Bible itself questions this view, most decisively in the teaching of Jesus himself
(e.g., the tower of Siloam, the man born blind). On the other hand, Thiel's desire
to distance God as much as possible from suffering and death may lead to a
rather tepid doctrine of creation. God may not have created the creature's
bondage to decay, but God did make creatures who were vulnerable to decay,
and who therefore suffer. Death is not "natural," but finitude is-and it is
difficult to imagine creatures who do not die, in at least a physical sense. God's
relation to suffering and death is extraordinarily complex. I worry that Thiel's
account may, despite his best intentions, result in a dualism in which God's
moral purity is preserved at the cost of his concrete involvement in the world.
What is needed here is a nuanced account of the relation between creation and
redemption. Such an account is made difficult when a single notion ("innocent
suffering") is made to bear too much weight.
Despite these problems, the book is a creative and challenging exercise in
Christian theology. Thiel's intellectual clarity does not come at the expense of
moral passion. He invites us to ponder how to respond faithfully to the mystery
of suffering in a world created by the God of life.
JOSEPH L. MANGINA

Wycliffe College, Toronto School of Theology
Toronto, Ontario, Canada

BOOK REVIEWS

479

Revelation and the Church: Vatican II in the Twenty-First Century. Edited by
RAYMOND A. LUCKER and WILLIAM C. MCDONOUGH. Maryknoll, N.Y.:
Orbis, 2003. Pp. 283. $24.00 (paper). ISBN 1570754799.
The reception of any general council is always a slow and arduous process.
Competing theological schools inevitably arise to claim fidelity to the true spirit
of the previous synod. The Second Vatican Council (1962-65) has predictably
engendered debate on some issues that were already neuralgic during its four
sessions (e.g., the relationship between papal primacy and episcopal collegiality),
and on other issues that would only surface in later years (e.g., the challenges to
marriage and procreative sexuality). A group of Catholic scholars has compiled
a collection of essays that seeks to move beyond the polarizations that have
resulted from disagreement over the nature, structures, and competencies of
Church authorities to engage those hotbed topics that continue to be ecclesially
divisive. Yet the present volume clearly takes its stand within a school that seeks
to correct, or at least query, current magisterial interpretations on the basis of
principles allegedly embedded in Vatican II's documents.
The career of Raymond A Lucker, the late bishop of New Ulm, Minnesota,
who died of cancer in 2001, serves as the inspiration behind this collection.
Throughout his episcopacy, and briefly into his retirement, Bishop Lucker sought
to fulfill the council's mandate to bring core Catholic teachings to bear on
contemporary realities, and in a manner persuasive to modern-day believers. In
recognition of his efforts to bridge scientific theology and pastoral practice, the
Catholic Theological Society of America honored him in 2000 with a lifetime
achievement award. Well into the final weeks of his battle with cancer, the
bishop took notes from his hospital bed on articles that addressed his favorite
theme of "change" and organic development in the life and teachings of the
Church.
The authors of this volume take up a number of Raymond Lucker's key
theological interests, and reflect on them in the light of the bishop's published
writings and private notes. Under the rubric of "revelation," the evolutionary
character of Catholic doctrine is discussed with a view to showing that no pope
or council ever achieves a final interpretation of an article of faith. In the other
three sections the essays treat a wide variety of themes having to do with
episcopal leadership, liturgy,life issues, and just war. Consistently, the authors
seek to widen the possibilities of acceptable positions against a perceived
narrowing of options by the Vatican over the last quarter century.
Among the many topics discussed, four may be highlighted as having
exacerbated tensions between the majority of the theological establishment and
the magisterium, but also between certain elements within the hierarchy itself.
Regardless of who Pope John Paul II's successor may be, the next papacy will still
be occupied with the issues of (1) the proper function of the Church's teaching
organs, (2) levels of authority in what the Church teaches, and (3) the
relationship between universal structures and local structures in carrying out the
Church's mission of evangelization.

480

BOOK REVIEWS

In matters such as the ordination of women and the Church's opposition to
same-sex unions, none of the authors-as far as I can tell-<lirectly endorse
positions opposed by the magisterium. Their criticism rather takes aim at the
processes by which the magisterium arrives at its determinations. Bishops Lucker,
in the essay that opens the volume, calls for a "free and open discussion" by all
bishops, theologians, and other lay faithful before Rome insists on submission
to its teaching on women and the priesthood. The implication to be drawn from
his statement is that the pope somehow failed to consult the broader church
when he issued the 1994 declaration Ordinatio sacerdotalis,which called for a
"firm assent" to the teaching that only men can be ordained. Along with Susan
Wood, Bishop Lucker finds the authoritative weight given to this teaching by the
Vatican rather dubious. Cardinal Ratzinger's 1995 "Response" to a query from
an episcopal conference states that the declaration merely confirms a
nonreformable teaching of the ordinarymagisterium, which is to say, a definitive
exercise of the entire episcopate scattered throughout the world but teaching in
concert. The clarification of the Congregation for the Doctrine of the Faith,
however, did little to dispel confusion for Bishop Lucker. He finds it
· questionable that the magisterium could teach definitively outside of an
ecumenical council or an ex cathedrastatement by a pope on a matter that does
not touch on the core of revelation. Within Bishop Lucker's categories, a
definitive teaching on matters that pertain to safeguarding the integrity of the
deposit of faith-what is traditionally referred to as "secondary object"-would
seemingly have to be generated by the extraordinary magisterium. In other
words, the issue of women's ordination ought to have been left for an ecumenical council, in which bishops meet on a even playing field to adjudicate
matters of great import for the entire ecclesial body.
The problem in applying Bishop Lucker's categories to the teaching on
women and the priesthood-as well as other rulings of the Holy See on such
matters as artificial birth control and the status of Anglican orders-lies with the
categories themselves. Since Vatican II there has been an expansion of the
purview of the ordinary magisterium in regard to definitive, nonreformable
teaching-partly due, I would suggest, to the need for the hierarchy to respond
quickly to pressing moral developments in both the scientific and political
arenas. Bishop Lucker wants an extended debate on matters that have polarized
portions of the faithful in the Western countries, while leaving definitive
pronouncements to rare exercises of conciliar or papal infallibility. But such selfimposed constraints could end up paralyzing the Church at precisely those
moments when her voice is needed to defend human dignity and human life
against the assaults of technology and certain deleterious trends in the culture.
As a shepherd who fostered many kinds of dialogue within his local church,
Bishop Lucker places great confidence in the capacity of the laity to recognize
Catholic truth. He is right to argue on the basis of Vatican II that the lay faithful
must be "consulted" in the development of teaching on faith and morals, and
that all definitively taught doctrine must undergo a "reception" "by the whole
body of the faithful" (Lumen gentium 12). Unless the teachings on marriage and

BOOK REVIEWS

481

family life are recognized as in accord with the faith by a preponderance of
devout Catholics, they will eventually be dismissed as mere hollow utterances.
But Cardinal Newman, in his defense of the need to consult the laity, carefully
distinguishes between "seeking their opinion"-as if the whole body had
specialized knowledge-and determining their deeper resonance, often expressed
devotionally, with what is being proposed de fide. In acknowledging the laity's
prophetic charism of truth, the contributors to this volume tend to underplay the
prophetic aspect of the bishop's ministry, which can be beneficially collaborative
and dialogical, but may at times also require taking a firm stand against the flow
of public opinion into which the more vocal portions of the laity are sometimes
swept.
In reading through the essays one also hesitates to go along with the way in
which certain concepts are employed philosophically. "We are always advancing
toward the full truth," Bishop Lucker asserts. "We do not yet have the fullness
of truth. No one does." Statements to this effect draw support from those
biblical exegetes and historians who apply critical methods to show up the timeconditioned character of past and present formulations of faith. Within the
dominant framework of this volume, truth becomes the hard-fought attainment
of the present generation that has the courage to pursue critical research and
dialogue to their limits. Only through communal discernment can the problems
of local adaptation of the liturgy, the moral limits of war, and the demands for
more participatory structures of church government be resolved. Our history has
taught us that the Church changes in her life and self-understanding, and to
remain a dynamic presence in the lives of today's Catholics it will have to
become more conscious of the hard lessons learned in regard to flexibility,
adaptability, and diversity.
While these values do indeed correspond to an authentic aspect of the
Church's mission, they can perhaps too easily tend to underwrite an inadequate
concept of truth that ultimately undermines credibility. If our understanding of
truth is to be fully Catholic, it cannot fail to do justice to our past inheritance
that makes possible any real advance in doctrinal or moral understanding.
Catholic engagement in either its own inner-ecclesial arena or the public square
begins with the premise that certain infallible truths make discussion possible.
We do not create them, for they precede us. Any discussion of the terrorist
attacks of September 11"', for instance, that does not presuppose the principle
that innocent human life can never be directly targeted for destruction is not
worthy of the Catholic's engagement. And while we may never exhaust nor
perfectly express the meanings of these non-negotiable truths, they come to us
adequately formulated by the authentic tradition whose guardians continue to
be the Church's pastors.
A major difficulty with several of the essays in this volume is that their
understanding of catholicity seems somewhat truncated. The ongoing
postconciliar debate over the legitimate autonomy of local churches, and their
corresponding episcopal conferences, reflects a larger problem of how we
conceive the catholicity of local communities. Squabbles over Rome's right to

482

BOOK REVIEWS

certify and withhold approval of liturgical texts and other pastoral initiatives of
the local hierarchy will continue to be a source of irritation until local
bodies-from the parochial to the national level-cultivate a proper sense of
communion that acknowledges that the Eucharist demands of every community
that celebrates it ("in union with John Paul our Pope ... ") a desire for direction
and confirmation from the organs of the universal Church.
William C. McDonough, in honor of his late friend and esteemed bishop, has
put together a series of essays that seek to advance contemporary discussion on
issues that divide Catholics. Some attempt faithfully to sum up official Church
teaching, and then respectfully invite reflection on the means by which it is
generated and disseminated. Others seem to read into papal and other
magisterial texts positions that are difficulty to justify-as when William
McDonough and Catherine Michaud assert that John Paul II's Jubilee
"apologies" constituted an actual "development of doctrine." Terence Nichols's
piece on evolutionary science and faith stands out as an example of Catholicism's
proper engagement with culture.
Raymond A Lucker chose for his episcopal motto the words of the
distraught father whose sick son Jesus' disciples were unable to cure: "Lord, I do
believe. Help my lack of faith" (Mark 9:24). Bishop Lucker and his academic
colleagues who have honored him with this volume show themselves to be men
and women deeply committed to passing on the faith in these troubled times for
the Catholic Church. Would that their efforts, however, had widened the
conversation to include other voices more resonant with the less trendy
convictions of John Paul II and his coworkers at the Vatican. Then we might
have h:id a conversation even more "catholic."
JAMESMAsSA

Immaculate Conception Seminary
Huntington, New York

Meister &khart: Analogy, Univocity and Unity. By BURKHARD MOJSISCH.
Translated by ORRIN F. SUMMERELL. Philadelphia: B. R. Griiner
Publishing Co., 2001. Pp. 215. $95.00 (cloth). ISBN 90-6032-465-X.
One of the main currents in German scholarship on Eckhart over the past
few decades has been to show how deeply Eckhart's thought was rooted in the
life-world of medieval religious praxis and the thought-world of high
Scholasticism. Mojsisch's book is among the best-researched and best-argued
products of this trend that, far from depreciating the originality of Eckhart, has
only made more striking Eckhart's originality and profundity by laying bare his
debt to Scholastic thought. It is therefore good to see this work available in

BOOK REVIEWS

483

English translation, since perhaps it will, from now on, receive more attention
from English-speaking scholars who can only benefit from its often dense, but
always illuminating, analyses.
Mojsisch remarks near the outset that, for Eckhart, as for all Scholastic
theologians, faith and Scripture form the basis of all genuine thinking. For
Eckhart, human reasoning attains to truth not by its own power but only insofar
as it is applied to unlocking the inner meaning of Scripture. By the same token,
the inner meaning of Scripture becomes intelligible only insofar as it is framed
in terms of rationesnaturales or "natural reasonings" that express the parabolic
content of Scripture in rational, conceptual form. As Mojsisch puts it, "Eckhart's
methodological demand consists in showing how the godly (divina) and the
human (humana) realms-the realm of the divine and that of the naturalia (res
naturales), artificialia and moralia-reciprocally illuminate one another" (8).
Eckhart, moreover-and this is the thesis of Mojsisch's book-articulates this
mutual illumination in terms of the Scholastic language of analogy, univocity,
and unity. Analogy articulates the relation of res naturales (and of the soul qua
res naturalis) to God; univocity articulates the relations immanent without the
Godhead (such as the Trinity and other divine mysteries). Both relations,
however, are grounded in the divine unity where, qua intellect, the soul is reborn
from analogically differentiated creature to univocally related son of God.
The strong influences of Thomas Aquinas, Albert the Great, and the German
Dominican School of Scholastic theology are evident on Eckhart's thinking, as
Mojsisch immediately makes clear. Particularly noteworthy is the concept of the
causa essentialisdeveloped by Theodoric of Freiburg, an older contemporary of
Eckhart. In Proclean fashion, Theodoric argues that there is a hierarchy of
essential causality in which each essential effect is contained immanently in the
essential cause above it. To the extent that an effect is independent from its
cause, it is related to its cause analogically; but to the extent that it is still in its
cause, it is related to it univocally. Eckhart's insight was to apply this notion of
causa essentialisto the nature of the intellect, which both essentially is and is not
what it knows. Eckhart develops this insight in the first two ParisianQuestions,
which Mojsisch explains in this way:
Beings are not beings in their cause, since the cause, insofar
as it is in itself, is thought as a causa univoca, which does not
effect something in the manner of a causa analoga, but instead
founds it in the manner of a principium (causa essentialis
primo-prima as principium) .... As a causa univoca, God is
not a being, since as such a cause he is reason and not the
cause of beings. Solely as a causa analoga does God make it
possible for being to be beings at all. (40)
As such, the intellect qua intellect, insofar as it is the principle or causa essentialis
of all existents, cannot be an existent itself. Thus, insofar as something is its

484

BOOK REVIEWS

intelligible essence, it is in its cause univocally speaking; but as existent, it is
outside of its cause and thus can only be spoken of analogically with its cause.
In his analysis of Eckhart's theory of analogy, Mojsisch concentrates on the
prologues to the Opus tripartitum-particularly on the thesis "Esse est deus." By
the thesis "Esse est deus" Eckhart means that all transcendental perfections
belong to God alone. Creatures themselves, insofar as they are limited and
conditioned, cannot be the source of these perfections; they must derive them
directly from God. Insofar as it is "this or that" existent, the creature has nothing
of existence, oneness, truth, or goodness in itself. These perfections can be
predicated of it only in the same way that "health" can be predicated of food or
urine: not formally but by imputation. "As Eckhart himself remarks, his doctrine
of analogy serves the sole purpose of underscoring the weakness of the creature
over against the sublimity of God, the sole purpose of demarcating the nullity of
the creature in itself' (59). Thus, the creature always "hungers and thirsts" after
God precisely because it lacks within itself any of the transcendental perfections:
in an argument very reminiscent of Plato's Symposium, Eckhart asserts that the
creature's very analogically delimited "being" is the desire and not the possession
of the fullness of existence.
But this is not the whole story: the creature qua human soul is capable of a
univocal relation with God not despite but precisely because of the "nullity" of
the creature in itself. The two paradigms that Eckhart uses to explain this
reiation between the soul and God are those of justice and the just man, on the
one hand, and archetype and image, on the other. The just man, insofar as he is
just, is related to justice in itself (i.e., God) not analogically but univocally.
Empty of himself, the just man does not appropriate the divine in-working in a
limited analogically way but in a fully univocal way in which God's working is
his working precisely because he accepts all things equally without appropriating
them to his own measure. The same with the image and its archetype: the image
insofar as it is image derives all of its being and acting from its archetype; it thus
does not appropriate the archetype analogically but univocally-all the while
remaining utterly distinct from its archetype since it is nothing in itself as image.
These two paradigms are paradigms for Eckhart of the soul's relation to God
insofar as the soul is just and lives out of God's image within it.
The moments of analogy and univocity, however, are united for Eckhart in
transcendent unity, which Eckhart defines as "indistinct" ("Unum est indistinctum"). Oneness, as a transcendental perfection, stands in immediate relation
to ens or esse precisely because it adds nothing to being-it introduces no
distinction or division into being and "for this reason it is able to display the gist,
the purity or the apex of being, the divine essence as the ground of being" (98).
As "indistinctum," the divine unity is indistinct from all existents; but at the same
time, this indistinction makes the divine unity utterly distinct from all creatures.
As such, it is opposed to all analogized being, representing the pure "isticheit"
or "is-ness" out of which all creatures have their "borrowed" existence. And this
purity of existence in which there is no division resulting from analogically
differentiated creaturely existence is n,othing other than the purity of the

BOOK REVIEWS

485

intellect: pure unity and pure intellect are interchangeable because both find
their utter distinction from all things in their utter indistinction from all things.
As Eckhart notes: "Deus enim unus est intellectus, et intellectus est deus unus."
It is thus in the final chapter, "The Theory of the Soul," that we find the real
payoff of Mojsisch's analysis. The doctrines of analogy, univocity, and unity
really describe and are rooted in moments in the inner life of the soul and its
union with God. It is thus no accident that Eckhart takes as his leitmotif the
Augustinian injunction: "Noli foras ire, in te ipsum redi. In interiore homine
habitat veritas. Et si tuarn naturarn mutabilem inveneris, transcende et te ipsum"
(131). Thus, insofar as the soul has "let go" of all creatures, it moves from
subsisting in its analogically differentiated being to being univocally related to
God, "adding nothing" to God by being without any attachment to creatures or
creaturely ideas (149). What Eckhart calls the "spark" of the soul is precisely this
possibility to be conformed to God not analogically but in a unity that gives birth
to a univocal relation between the soul and God. In particular, and in marked
contrast to Albert and the entire German Dominican School, Eckhart sees the
possible intellect (as opposed to the agent intellect) as the basis of the divine
image within the soul precisely because the possible intellect is both all things
and none of them: it does not receive the divine being in an analogically
differentiated way but is able, due to its own inherent "nothingness," to be
conformed univocally to the divine in-working.
That is why, for Eckhart, John was closer to the truth than Paul when he said
that we were no longer "servants" but "friends" of God: "As servant (according
to Paul), the spark of the soul, or the ground of the soul, is subject to the relation
of analogue dependence; as friend (according to John), it is characterized by
univocal correlationality, and is to this extent beyond the created being of the
soul, being uncreated and uncreatable" (155). As Mojsisch further explains,
"This innermost of the soul is univocally related to transcendental being" (158).
This transition from analogically differentiated to univocally related being is
made not through theory but through spiritual praxis-the praxis of detachment
and letting go whereby there is actually "nothing" in the innermost ground of
the soul to be analogically differentiated: "He is supposed to have nothing, not
to be a place in which God can act analogically, but instead to let God act in
himself and to be God's acting in himself" (160-61). The entire thinking of
Eckhart could, then, be summed up by his short aphorism: "Aliquid est in anima,
quod est increatum et increabile; si tota anima esset talis, esset increata et
increabilis, et hoc est intellectus" (169). Qua creatures, human beings are
analogically related to the pure being of God; but qua intellectual, we can come
to share univocally in the life of the divine unity.
I have only three relatively minor criticisms to make of the book. The first
has to do with the introductory pages: Mojsisch does not make clear his thesis
until after several pages of what are, in my view; superfluous, disorienting, and
highly abstract general theoretical considerations. He could have dispensed with
the first six pages without any loss to his argument. My second comment has to
do with the translation itself. Orrin Sornmerell is to be commended for tackling

486

BOOK REVIEWS

such a difficult text and producing a good workable translation out of difficult,
academic German. Nevertheless, too often the translation reads not like natural,
if academic, English prose but precisely like a translation from academic German
in which the sentences are overly long and the subordinate clauses tangle and
pile up. Finally, while the editors are to be commended for retaining all citations
from Eckhart in the original Latin or Middle High German, they leave these in
the text and relegate the English translations to an appendix. This arrangement,
to be sure, presents no difficulty to the Eckhart scholar; but in view of a more
general readership, which this book merits, it would have made more sense to
reverse this arrangement.
But these criticisms are, as I have said, minor. This work is essential to any
understanding of Eckhart and should be in the library of any institution where
Eckhart's works are taught and studied.
ROBERTJ. DOBIE
La Salle University

Philadelphia, Pennsylvania

Mystical Consciousness: Western Perspectives and Dialogue with\]apanese
Thinkers. By LOUIS ROY, O.P. Albany, N.Y.: State University of New '(ork
Press, 2003. Pp. xxi + 229. $62.50 (cloth), $21.95 (paper). ISBN 0-79145643-9 (cloth), 0-7914-5644-7 (paper).
In order to avoid expecting more from this book than the author intends,
one must note carefully some key distinctions he makes in his preface and
introduction. For one thing, although the Japanese Zen thinkers Daisetz Teitaro
Suzuki, Nishitani Keiji, and Hisamatsu Shin'ichi are treated in the last three of
the book's ten chapters, Roy deals almost exclusively with Western thinkers in
the first seven chapters, in accordance with his stated aim of furthering a Western
philosophy of religion (xi). The dialogue with Japanese thinkers announced in
the subtitle is therefore not extensive or pervasive. Moreover, Roy expressly
limits his understanding of mystical consciousness to states marked by low levels
of physiological and cognitive activity and therefore does not deal with any
mystical phenomena that could be described as "consciousness-of"; he thus
excludes not only somewhat uncommon phenomena like visions and auditions
but also thoughts and feelings that could be a normal part of someone's
relationship with God. This restriction, he claims, allows him to deal only with
that sort of mystical consciousness that can quite easily be brought into dialogue
with Zen (xx).

BOOK REVIEWS

487

That last-named exclusion means that Roy will focus on only the last two of
the following three kinds of consciousness to which he alludes at numerous
places in his book. "Consciousness-of" he terms "consciousness C," the
consciousness we have of things and people in our ordinary activities. It is, by
definition, an awareness of objects. Likewise part of our ordinary consciousness
is what Roy calls "consciousness B," a prereflective, unobjectified kind of
knowing that permeates all of our ordinary states and activities. One simply
knows that something is happening without knowing any specific object.
"Consciousness A," by which Roy means mystical consciousness (in the restricted
sense of mysticism indicated above), is likewise "consciousness-in," but unlike
consciousness B it obtains in objectless states, states beyond any distinction
between subject and object, the kind of state regularly called "emptiness" in
Mahayana Buddhist thought. Roy deals primarily with these two forms of
consciousness-in (especially consciousness A) and states that one of his main
objectives is to show that it is not only Eastern thinkers who have recognized and
written about them. As he says in the final paragraph of the book, "I hope I have
demonstrated that, contrary to what is commonly believed, numerous thinkers
in the West have delved into the riches of those human discoveries" (191).
Roy's attempted demonstration begins with a survey of Western philosophies
of consciousness (part 1 of the book, consisting of three chapters), proceeds
through a fairly detailed consideration of three "classic" Western thinkers (part
2, with chapters on Plotinus, Eckhart, and Schleiermacher), and concludes in
part 3 with "a dialogue with Zen philosophy," consisting of paired chapters on
Western and Japanese views of the self (chapters 7 and 8) and a second paired
set on Western and Japanese views of nothingness.
In his opening two chapters Roy treats Western philosophical accounts of
ordinary consciousness, relying primarily on the works of Brentano, Husserl,
Sartre, and Lonergan but supplementing these with references to more recent
and lesser-known scholars like John Crosby and Elizabeth Morelli. One of the
most important parts of these chapters is Roy's treatment of Sartre. Following
Husserl, the French philosopher insists in Being and Nothingness that all
consciousness is consciousness of something; there is, he claims, no consciousness
that is not a positing of an object that transcends purely immanent mental
operations. Despite this insistence, Sartre does recognize the existence of what
Roy calls consciousness-in as the condition of consciousness-of, as when Sartre
writes in The Transcendence of the Ego of a "non-positional consciousness" that
does not posit itself as its own object, or when in Being and Nothingness he
affirms that the consciousness we have of ourselves is not some addition to the
consciousness that we simply are: "This consciousness, as we know, can be only
non-positional; it is we-as-consciousness since it is not distinct from our being."
Roy concludes his first two chapters by noting that consciousness-in usually
accompanies intentionality, that is, consciousness of objects in our normal daily
experience. He claims that there is, however, an exception to this, a kind of
consciousness-in where intentionality is not operative. This is mystical

488

BOOK REVIEWS

consciousness, in the restricted sense noted at the beginning of this review. That
there is such consciousness has been affirmed by a number of thinkers to whom
Roy alludes, including Robert Forman, Sebastian Moore, James Price, David
Granfield, and-above all-Bernard Lonergan. What Roy finds especially
pronounced and crucial in Lonergan is his insistence that there is a kind of
immediacy that derives not from the data of sense but from the data of
consciousness. This is a "mediated immediacy"-mediated inasmuch as it is
necessarily shaped by language, but immediate in that it is given to us directly in
the awareness we have of our own acts and states. When instantiated in any kind
of union that takes place between humans, it is necessarily embodied in sensory
perception and movement, whereas mystical union transcends such limits by
heading toward what is infinite in meaning and value. All values trigger affective
responses, including relatively permanent feelings of which the most basic is that
of being in love. When such being-in-love constitutes the sort of religious
disposition that is unconditional and unrestricted, we have what Lonergan calls
"being in love with God." This point is absolutely pivotal for the rest of Roy's
book, for the "more" of mystical experience is precisely "the element of infinite
lovingness" (50). At crucial junctures in his book, Roy regularly notes the
affective nature of mysticism in the restricted sense in which he uses the term.
While refusing to affirm that love is "the kernel of mysticism" (the Japanese
writers with whom Roy is in dialogue usually refrain from talking about love
since it is generally viewed as the locus of desire and the pursuit of self-centered
gratification), Roy nevertheless does make a claim which I take to be the most
central in his entire book, namely, that all the thinkers he has discussed "would
undoubtedly concur that mystical consciousness is the most important ingredient
of a personal transformation which roots out obstacles to genuine loving" (189).
Perhaps the best way of indicating the significance of the treatment of
Plotinus, Eckhart, and Schleiermacher in the three chapters of part 2 is to say
that Roy uses their writings to show what he means by claiming that mystical
consciousness, unlike consciousness B, is not "part and parcel of intentionality"
(32). After all, could one not argue that God is the mystic's intended object, the
object of a Lonerganian "being in love in an unrestricted fashion"? No, Roy
would reply, precisely because the mystic does not meet God as an object over
against himself or herself. For Plotinus, the soul partakes of the Intellect (nous)
even as the Intellect partakes of the One or the Good (which Plotinus sometimes
calls God or the Father), and in such participation the soul is entirely void of any
act of understanding. In Plotinus's words, the soul "puts away all the shape
which it has, even whatever shape of the intelligible there may be in it" (Enneads
6.7.34); it is "without form" and "ignoring all things" (6.9.7). Union with the
One is not identity, but it is felt as identity: "The seer does not see and does not
distinguish and does not imagine two, but it is as if he had become someone else
and he is not himself, ... having joined, as it were, centre to centre" (6.9.10).
This same kind of experienced transcending of dualism is also found in
Eckhart. Roy quotes what is perhaps Eckhart's best-known German sermon as

BOOK REVIEWS

489

a particularly forceful expression of this transcendence: "While I yet stood in my
first cause, I had no God and was my own cause: then I wanted nothing and
desired nothing, for I was bare being and the knower of myself in the enjoyment
of truth" (Sermon 52). Such claims, which got Eckhart into trouble with the
guardians of ecclesiastical orthodoxy, can only be understood by adverting to the
opening clause of Eckhart's sentence and its basis in the traditional doctrine of
the divine ideas, which are strictly one with God in the divine simplicity. The
mystic's "breakthrough" (durchbruch) is the movement away from a nameable
God to the utterly simple, ineffable Godhead that Plotinus regularly called "the
One." Eckhart's main differences from Plotinus-and in Roy's view a definite
advance over the pagan thinker-are, first, that Eckhart does not see mysticism
as an escape from the body, a flight of the alone to the Alone, but rather teaches
that eternity can be actualized "when one is busy with ordinary chores" (94),
and, second, that this actualization can be a lasting state or disposition and not
simply a discrete, momentary event, as Plotinus implies.
The third and last "classic" thinker whom Roy discusses in part 2 of his book
is Friedrich Schleiermacher. This chapter simply incorporates the major part of
an article Roy wrote for the Journal of Religion together with some paragraphs
from an article in the journal Method. Although Roy astutely shows that
Schleiermacher, unlike many German thinkers, recognizes the reality of a
prereflective consciousness as distinct from the unconscious on the one hand and
reflective consciousness on the other, Roy devotes much of the chapter to
faulting Schleiermacher for failing to give a successful explication of
consciousness-in. In this sense, Roy does not here advance his argument in any
pc,sitive way. I believe the other chapters would have cohered better if the
Schleiermacher material had been left as a self-contained article instead of being
inserted into this book.
Part 3 of the book is especially interesting, for it is only here that Roy makes
the case for a convergence between the thought of Western thinkers like
Plotinus, Eckhart, and Lonergan and that of the Zen thinkers Suzuki, Nishitani,
and Hisamatsu. In his fourth chapter, dealing specifically with Eckhart, Roy had
already stressed the medieval Dominican's insistence on detachment
(abegescheidenheit) from everything, not merely material possessions and
pleasures but even religious practices and a sense of doing God's will. In the
same Sermon 52 quoted above, Eckhart says, "As long as a man is so disposed
that it is his will with which he would do the most beloved will of God, that man
has not the poverty we are speaking about, for that man has a will to serve God's
will-and that is not true poverty!" In his final chapters, Roy points out
numerous parallels to this kind of detachment in the Zen writers, a detachment
that in both East and West is commonly spoken of in terms of conversion.
Nishitani writes of an "existential conversion" in which "the self does not cease
being a personal being. What is left behind is only the person-centered mode of
grasping person, that is, the mode of being wherein the person is caught up in
itself." Having left that behind, what remains is "emptiness," which Nishitani

490

BOOK REVIEWS

calls "a standpoint of absolute non-attachment" that opens up "a place which in
every way serves as the ultimate locale for a meeting between people."
It is this emphasis on interpersonal encounter, which at one point Nishitani
even calls "a field where self and others are bound together in divine agape," that
allows Roy to emphasize how authors from both the Western and Zen traditions
highlight the affective side of mystical consciousness. As noted earlier, Roy is
reluctant to call love simply "the kernel of mysticism," but in the final,
summational paragraphs of his book he makes the strong claim that "mystical
enlightenment creates an ambience of equanimity ... thanks to which authentic
love, compassion, and patience, which allow a person to transcend oneself
towards other people, become natural (albeit not easy) and work themselves out
in act-like affects and in deeds" (189-90). Roy admits that mystical consciousness
can be distorted. People can become attached to their meditative or contemplative practices or complacently enjoy their spiritual pedormance, which is why
Roy approvingly quotes Bergson to the effect that the complete mystic is one
whose "contemplation is engulfed in action" and adds that "in their insistence
on action, Bergson, Eckhart, and the Japanese Zen practitioners remarkably
converge" (190).
From my own conversations with some Japanese practitioners of Zen I can
readily affirm Roy's final point. The hours of sitting in the meditation hall are
integrally related to the rest of one's life, so much so that flashes of enlightenment may occur just as frequently in the kitchen or rice paddy as in the zendo.
The convergence with Eckhart and other mystical writers in the Christian
tradition is obvious. That this "insistence on action" concerns not only the way
we refa.te to other persons but also to the rest of the world around us is also
rightly emphasized by Roy, above all in his reference to the way Nishitani
understands the salutary effect of Francis of Assisi's addressing a cauterizing iron
as "Brother Fire," a passage that Roy considers the high point of Nishitani's
Religion and Nothingness (177). For these reasons, Roy can certainly be said to
have met his objective of making a contribution toward showing how intedaith
dialogue can be enhanced by using the language of consciousness. His book
could accordingly serve in graduate courses in interreligious dialogue as well as
in more general courses in the philosophy of religion. The only significant
weakness of the work is the intrusion of the chapter on Schleiermacher (who is
scarcely even mentioned elsewhere in the book), though any revised edition
could also profit from a more thoroughgoing integration of the material from the
East instead of relegating it primarily to the final four chapters.
JAMES A. WISEMAN, 0.S.B.

The Catholic University of America
Washington, D.C.

BOOK REVIEWS

491

Les anges et la philosophie: Subjectivite et fonction cosmologique de substances
separees a la fin du Xllle siecle. By TIZIANA SUAREZ-NANI. Paris: Vrin,
2002. Pp. 204. 24 €(paper). ISBN 2-7116-1514-6.
Connaissance et langage des anges. By TIZIANASUAREZ-NANI.Paris: Vrin, 2002.
Pp. 271. 30 €(paper). ISBN 2-7116-1572-3.

Tiziana Suarez-Nani's two-volume "philosophical portrait of the angel"
encompasses four themes. The subjectivity of the angel and the cosmological
function of spiritual creatures are treated in the first book, and angelic
knowledge and communication in the second.
Suarez-Nani begins Les anges et la philosophie by observing that the notion
that angel-like beings exist derives from a long tradition of conceiving the
universe as ordered, where order is understood to consist in hierarchy and
interconnection. She then introduces the principal figures in this tradition.
Proclus and other neo-Platonists advocated the view that there should be an
uninterrupted chain of intermediary beings between the first principle and the
least of the beings derived from it. Pseudo-Dionysius, while rejecting many of the
details of Proclus's system, retained the general notion that the universe requires
a hierarchical structure, to which he added notions of his own. According to
Suarez-Nani, the Book of Causes was even more influential than PseudoDionysius for the elaboration of philosophical views concerning angels in the
thirteenth century (Les anges et la philosophie, 19). This work was successful in
transmitting neo-Platonism to the thirteenth century because its re-elaboration
of Proclus was close to the metaphysics of Pseudo-Dionysius-that is, it was
monotheist and creationist, and devoid of demigods. Other influences on
thirteenth-century angelology include Aristotle, Avicenna, and Augustine. The
thinkers whose views Suarez-Nani intends to examines in depth are two students
of St. Albert, Thomas Aquinas and Thierry of Freiberg.
The first chapter of part 1 is entitled "The Angelic Subjectivity: Nature and
Individuation of Angels." (I do not recall Aquinas speaking of "subjectivity"; it
would have been useful to define this term.) By way of preface, Suarez-Nani
speaks about the reason why Aquinas regards angels as needed for the order of
the universe. The discussion here is one of the least satisfying parts of a book
that insists upon the pertinence of philosophy to questions concerning angels. It
would have been helpful if all of the philosophers who made a case for the
existence of separated substances-or even just those whom Aquinas mentions
in his opusculum on separated substances-had been surveyed, and then
categorized.
Suarez-Nani explains how Aquinas's position on the existence of angels
derives from his position on the finality of creation. Aquinas holds that God
creates because he desires to communicate his goodness, and in doing so to
produce something like unto himself. Since no single creature comes in any way
close to being an adequate likeness of God, God produces a diversity of beings.
Suarez-Nani does not ask whether the notion that God freely creates in order to
share his goodness with other beings, and thereby produce a reflection of his

492

BOOK REVIEWS

own goodness, is philosophical or theological, and if philosophical, who first
enunciated it. Once it is granted, it is not hard to see that the universe would be
defective as a reflection of God if there were no beings that were like to God by
having a purely intellectual nature (ibid., 30).
Suarez-Nani next takes up the manner in which angels are individuals. She
first explains Aquinas's teaching on matter as principle of individuation in
material beings, and then gives a straightforward exposition of his teaching on
the individuality of angels. I question though her assertion that "the [imperfect]
condition of the human individual ... is ultimately due to a material substrate
which imprisons [the individual]" (ibid., 45). That something is imperfect is not
synonymous with its being defective. Human beings are less perfect than angels
because of their body and their mode of cognition which is dependent upon
sense knowledge obtained through the body. This does not conflict with the
notion that the reason the human intellect is united to the body is for its
perfection, something Suarez-Nani acknowledges in her second book
(Connaissanceet langage des anges, 31).
In chapter 2, Suarez-Nani considers the views of Thierry ofFreiburg. Thierry
holds that "one individuality is constituted each time parts are added to the
essence of a thing, though these parts are not necessarily material" (Les anges et
la philosophie,56). This is the basis for his position that there can be many
angels of the same species. Aquinas, on the other hand, maintains that a
multitude of angels of the same species could not exist any more than a
multitude of separated whitenesses could exist-whiteness is not many except
according as it is found in many substances (STh I, q. 50, a. 4). Suarez-Nani does
not att.:mpt to adjudicate between these two views. She in fact misunderstands
Aquinas's views on individuation. Aquinas never says that "one form can only be
individuated by its reception in matter" (Les angeset la philosophie,61), but only
that things that agree in form can only differ numerically due to matter. This
mistake may be at the root of Suarez-Nani's assertion that "the angels of Thomas
... are not individuals, but realities possessing a certain universality" (ibid., 72).
Aquinas, to the contrary, affirms that angels are persons (ScG N, c. 55), and by
"person" he means an individual substance of a rational nature.
Another place where it would have been helpful to put Aquinas's views
alongside Thierry's regards Thierry's hierarchy of being: the One (God),
Intelligences, souls of the heavens, angels, human souls. This hierarchy is based
on notions such as that one intelligence can proceed from another by a mode of
essential causality which was given to it by God, a mode of production inferior
to creation (Les anges et la philosophie,64, 68), and that the intelligences "are
intellects by essence, who are not subject to any difference between their faculty,
their operation, and their substance" (ibid., 66). Aquinas is open to the existence
of intelligent creatures other than humans and angels, but rejects Thierry's
Proclean schema, holding rather that immaterial creatures cannot assist in the
production of another immaterial being (ibid., 98), and that in God alone there
is an identity of faculty, operation, and substance.

BOOK REVIEWS

493

The second part of the book is devoted to examining the view that separated
substances are movers of celestial bodies. Aristotle's rationale for this view is that
the motion of these bodies (circular, unchanging, and eternal) appears to be
qualitatively different from the motions of bodies on earth, and this requires a
proportionate cause. According to Suarez-Nani, the reason that eternal,
immobile causes other than the unmoved mover are needed to account for these
motions is that the unmoved mover "cannot directly apply itself to the celestial
spheres" (ibid., 95). Aristotle never says that. Rather he attributes the simple
spatial movement of the universe to the prime unmoved mover (Metaphysics
1073a29, 30), and thinks that the other eternal motions such as those of the
planets should each have their own immobile and eternal mover. Suarez-Nani
next discusses Aquinas's rejection of Avicenna's intermediaries which are
creators. She notes in regard to change, as opposed to creation, Aquinas accepts
the need ("exigence") for mediation. It would be worth pointing out that such
mediation is not an absolute necessity, but that God freely chooses to use
secondary causes in order to communicate greater goodness to creatures, by not
only making them to be, but also to be causes. The notion that it is appropriate
for a king to have many ministers should also have been more fully developed
(Les anges et la philosophie, 114 n. 2, and 142). Suarez-Nani does not
consistently distinguish what God as omnipotent could do, but would not do, in
keeping with his wisdom.
After noting that Aquinas shares Aristotle's views about the imperishable
nature of the heavens, Suarez-Nani goes on to lay out Aquinas's arguments for
why the motion of the heavenly bodies depends on an intellectual substance as
mover, rather than on an intrinsic principle or an external material mover. One
is left wondering whether anything in Aquinas's arguments can be recuperated
given the false view he had about the nature of the stars and planets. Is there
anything to the notion that nature is submitted to the action of separated
substances? The notion of a twofold order in the universe that Thomas speaks
of would have been useful for sorting out the philosophers' views on separated
substances: "order in things is found according to these two things, namely,
according as one thing is better than others, and according as one is moved by
others" (STh I, q. 103, a. 4, ad 1). Hone looks at the general notion, and not at
the details of the philosophers' views, it seems reasonable to think there would
be a being intermediary in excellence between God and humans. It is harder to
find a philosophical justification for the notion that these beings play a causal
role vis-a-vis material creation.
Suarez-Nani asserts that while Aquinas was not preoccupied with whether the
separated substances moving the heavens are the angels of the Dionysian
hierarchy, one can argue that the two coincide (Les angeset la philosophie, 117).
Although Aquinas does not ask whether angels and the philosophers' separated
substances are the same beings in precisely those terms, in SI'h I, q. 110, a. 1 he
does give an affirmative answer to the question of whether angels preside over
the movements of corporeal creatures, noting that philosphers and Doctors alike
held that there were incorporeal substances that ruled over the corporeal realm.

494

BOOK REVIEWS

He seems to regard the angels' rule over corporeal creation in a generic way
which includes both bringing messages to humans, as well as moving natural
bodies (STh I, q. 112, a. 1, ad 4). Indeed, for Aquinas, that an angel be sent as
minister is equivalent to the angel "doing something in regard to some corporeal
creature according to divine command" (STh I, q. 112, a. 4). Moreover, he
answers the question of whether all angels are sent on missions by reference to
the Dionysian hierarchy, where it is the lower angels who interact with humans,
while mid-ranking angels act on the heavens. Unlike St. Albert who appears to
have thought that philosophy has nothing to say about the angels of theology
(Les anges et la philosophie, 126), Aquinas regards the two descriptions of these
immaterial beings as compatible. At the same time he counsels against binding
theological teachings about angels to determinations made by philosophers (ibid.,
131). And on the question of whether the heavens are ensouled, he says that it
is of no concern to the faith one way or the other (ibid., 137 and 167 n. 1).
The chapter devoted to Thierry of Freiberg and the animation of the heavens
seems of dubious value in this context. What seems to be typical of Thierry and
of every philosopher who treats of separated substances is that each has his own
system of intermediaries with no hard evidence to back it up. Eternal heavenly
bodies make a nice intermediary in theory, and animated ones perhaps less so,
but the reality is that these things do not exist, and it is chiefly of historical
interest by what defective reasoning and/or verbal gymnastics the philosophers
concluded that the existence of such intermediaries was necessary.
Suarez-Nani begins Connaissance et langage des anges by recounting
Aquinas's views on angelic knowledge, following closely the Summa Theologiae.
"The angel is a purely spiritual substance which subsists as a pure form--or
essence-<lependent as to its being, and by that very fact marked by potentiality"
(Connaissance et langage des anges, 20). Angels are limited beings whose nature
does not comprehend all things, and for this reason they need to be perfected by
intelligible species in order to understand things. These species cannot come
from things, as is the case of humans who acquire ideas starting from sense
experience of things, because angels are immaterial. The source of these species,
then, must be God. As coming from God, "Formae intellectus angelici sunt
excellentiores rebus ipsis, utpote divinae essentiae propinquiores" (ibid., 29).
Morever, the closer the angel is to God who knows all things by knowing
himself, the fewer and more universal its intelligible species are.
Suarez-Nani next takes up angelic cognition from the point of view of what
is known, starting with the angel's knowledge of itself. Angels do not need an
intelligible form to know themselves because they are "in the genus of intelligible
things as a subsisting intelligible form" (STh I, q. 56, a. 1). They thus know
themselves through their own form. Suarez-Nani points out how this selfknowledge constitutes a certain intermediary between divine and human
knowledge. God knows all things through himself, while humans require a
medium cognitionis for every object of thought, including their humanity. Angels
know themselves through themselves while requiring a medium cognitionis for
everything else, other angels included. Suarez-Nani sees this intermediary

BOOK REVIEWS

495

character of angelic knowledge as filling the function of a connexio universi
(Connaissance et langage des anges, 39). AB for knowledge of God, angels do not
know him through an intelligible species such as they have for other things, but
they know him (granted they do not comprehend him) by knowing their own
nature insofar as "the image of God is impressed in the very nature of the angel
through its essence" (STh I, q. 56, a. 3). The angel is thus a mirror of sorts
representing God's image.
Suarez-Nani next walks us through STh I, q. 57, aa. 1-5, where Aquinas
explains whether angels know material things, individuals, and future
contingents, secrets of the heart, and mysteries of grace; she then considers STh
I, q. 58, aa. 1-7, concerning the modalities of angelic knowledge.
Part 1, chapter 2 takes up the views of Giles of Rome. Giles argues in favor
of the need for intelligible species in order for an angel to understand things
other than itself, using Aristotle's reasoning in De Anima. The thing known must
be in the knower in some way. It cannot be in the knower entitatively. Therefore, it can only be in the knower by way of likeness. Giles and Aquinas agree
that the intelligible forms in the angels do not come from things, and both adopt
the Augustinian position that "just as the ratio by which a creature is made is in
the Word of God prior to being in the creature itself which is made, thus also
knowledge of that same ratio first comes to be in the intellectual creature, and
then exists in the very make-up of the creature" (STh I, q. 55, a. 2; Connaissance
et langage des anges, 119, 120). Giles further holds that "the proper object of the
angelic intellect is neither the universal nor the particular, but the whole thing
according to its entire being" (Connaissance et langage des anges, 106). (SuarezNani omits to consider whether Aquinas would agree with this.) Giles takes up
an interesting objection to the notion that angelic species are innate and not
received from things, namely, that this view seems unable to account for how the
angel knows new events, such as a baby being born (ibid., 122). It seems that the
event itself would cause a change in angelic knowledge. Giles maintains that
"when things come forth into existence the angel begins to understand other
things which it did not understand before through the same species that it
[always] had within itself" (ibid., 157 n. 3). Aquinas seems to adopt the same
view in STh I, q. 57, a. 3, ad 3, although our author does not mention this.
Too often Giles's and Thomas's view are not put side by side. Thomas denies
that angels can know what any rational being is thinking, other than by probable
signs, while Giles affirms that higher angels can know which intelligible species
a lower angel is thinking about, albeit not precisely what the latter is considering
in that species. A comparison of the rationale .each gives would have been
helpful. It would also have been useful to compare the three acts of cognition an
angel can carry on simultaneously that Giles speaks of to the morning and
evening knowledge that Aquinas speaks of.
Suarez-Nani begins her discussion of Aquinas's views on angelic speech
(locutio) by distinguishing locutio from illuminatio. In the Summa, Aquinas takes
the position that "in angels, all illumination is speech, but not all speech is
illumination" (STh I, q. 107, a. 2). Suarez-Nani only mentions his position in the

496

BOOK REVIEWS

Sentences (I Sent., d. 11, q. 2, a. 3), namely, that speech differs from illumination
in revealing a content that does not intellectually perfect the other (Connaissance
et langage des anges, 187, 198). She does not alert us to the (apparent) change
of view. Aquinas does consistently hold that lower angels can speak to higher
angels, but cannot illuminate them. Suarez-Nani also misses Aquinas's reason for
why an angel's thoughts are unknown to other angels, unless it chooses to reveal
them (ibid., 189), a reason that applies to angels and humans alike: "The will of
the rational creature is subject to God alone, and therefore those things which
depend on the will alone . . . are known to God alone ... a manifest case of
[which] is that a person consider something in act" (STh I, q. 57, a. 4). Since it
is the angel's will alone that prevents other angels from knowing its thoughts, in
order for it to manifest its thoughts to another, it simply has to will to do so (STh
I, q. 107, a. 1, ad 1). One cannot help but marvel at the beauty of a form of
speech that results in perfect ·understanding between speaker and listener
(Connaissance et langage des anges, 207).
The discussion of exactly what effect one angel has on another when it
speaks to that other is less than satisfying. Suarez-Nani quotes De Veritate, q. 9,
a. 5, ad 2 to the effect that "angelus loquens nihil facit in angelo cui loquitur."
However, this is a response to a specific objection, namely, that it would be
incongruous for a lower angel to speak to higher angel. It is far from clear that
an angel who is spoken to is never affected by the speaker (e.g., when the
speaker reveals mysteries of grace previously unknown to the listener). Indeed,
De Veritate, q. 9, a. 2 seems rather to indicate that angels can cooperate in a
certain manner with God in perfecting a listener (something that Suarez-Nani
seems to acknowledge later on [ibid., 117)). Towards the end of the chapter,
Suarez-Nani claims that Aquinas does not address whether angels speak to
humans because it is an "embarrassing" question liable to "compromise the status
of angels as purely spiritual beings" (ibid., 204). However, Aquinas in fact
specifically mentions speech in STh I, q. 52, a. 3, where he asks whether angels
exercise life activities in the bodies that they assume. Plainly angels are not going
to communicate to us by simply choosing to reveal their thoughts to us, given the
limitations of our mode of understanding. Angels will then have to move bodies,
in a way reminiscent of a voice-synthesizer, to communicate with us in a manner
we can understand.
I was not convinced that Giles of Rome contributes much to understanding
the speech of angels. For instance, he holds that angels communicate with each
other using sensible signs such as they use when communicating with us. Now,
one uses sign language to communicate with a person who can hear when that
person does not speak one's language; there would be no point in doing so with
someone who did (i.e., with a view to communication alone). Why then would
angels use an inferior form of communication to speak to each other? Giles
would even have angels communicating via images they generate in the
imagination of a human or animal (ibid., 213). He also claims that angels write
messages in the heavens to each other which cannot be read by humans (ibid.,
215). For Giles, angels cannot by simple choice reveal specifically what they are

BOOK REVIEWS

497

thinking to other angels, but need to do so via the intermediary of a signum
intelligibilium. But there is an obvious problem with this position: either this
intermediary is natural the way a concept is naturally a likeness of things, or it
is arbitrary. If it is natural, then it is redundant. If it is arbitrary, how would it
ever become associated in the mind of another with the concept the angel wished
to communicate? The latter criticism also applies to the heavenly writing which
Giles says is arbitrary (ibid., 238). It never occurs to Giles that the arbitrary sign
can have no meaning to another unless there is some way for the other to
connect the sign to its content. Human beings do this in the first instance
through pointing or the like. Yet according to Giles, regardless of what arbitrary
sign an angelic speaker chooses to use to express a given thought, that thought
will be immediately understood by other angels to whom the message is directed
(ibid., 236). Such an association of sign with thought would be possible if the
listening angel knew the other angel's thoughts when the other chose to reveal
them-but then the addition of an arbitrary sign would be superfluous.
Suarez-Nani repeatedly suggests that angels are models or paradigms for
humans with respect to knowledge (ibid., 141, 148), speech (ibid., 207), and, in
her first book, subjectivity as well (Les anges et la philosopht"e,188, 189). While
there are points of contact-as is to be expected in a well-ordered universe (e.g.,
the habit of intellectus in humans)-angels and humans are also meant to differ,
and thus the more perfect cannot always serve as a model for the less perfect.
Humans cannot do other than acquire intellectual knowledge starting from sense
experience, nor can we do without sensible signs in order to communicate.
Suarez-Nani does admit that we are not to take angelic knowledge as our norm,
but this observation is tucked in a footnote, and more often we are told the angel
represents "an ideal that the human being aspires to" (Connaissanceet langage
des anges, 169). Also problematic is her insistence on how much angelology can
teach us about ourselves (ibid., 9, 169, 170). Human cognition and speech are
things we have direct experience of, and thus the nature of these things is better
known to us than is the nature of angelic cognition and speech. In some ways our
understanding of angelic cognition is dependent upon our understanding of
human cognition (e.g., we understand angels' intelligible species by reference to
the concepts in our practical intellect). Acknowledging this dependency does not
preclude affirming that the comparison of humans to angels does give us a better
understanding of ourselves and of our place in the universe.
Suarez-Nani is to be commended for daring to treat so difficult a
philosophical subject as the angels. She brings to our attention a wealth of
fascinating texts (including the articles on angels included on the syllabus of
errors in 1277). The scholarship is thorough, and the copious Latin footnotes
very helpful. One can hope that as a result of her efforts philosophical reflection
on angels will come back into vogue.

MARIEi.GEORGE

St. John's University
Jamaica, New York

498

BOOK REVIEWS

Thomas Aquinas: Theologian of the Christian Life. By NICHOLAS M. HEALY.
Aldershot, England: Ashgate, 2003. Pp. 168. $29.95 (paper). ISBN 07546-1472-7.
In his classic The Nature of Doctrine: Toward a Post-Liberal Theology,
George Lindbeck distinguished between a cognitivist, an experiential-expressivist, and a cultural-linguistic understanding of Christian doctrine. The major
approaches to the interpretation of the thought of Thomas Aquinas over the past
century can be seen to correspond, mutatis mutandis, to these categories. The
neo-Scholastic school-represented by Garrigou-Lagrange, Maritain, Journet,
and in recent times, Ralph Mcinerny and John Wippel-presents a rather
cognitivist version of Aquinas, stressing the philosophical doctrine that can be
distilled from Thomas's oeuvre. The Transcendental Thomist schoolinaugurated by Marechal and Rousselot and brought to prominence by Lotz,
Rahner, and Lonergan--offers a more experiential-expressivist reading of
Thomas, emphasizing the subjective sensibilities that inform and condition his
teaching. In the last couple of decades, a third school has emerged, one that
places emphasis neither on propositions nor underlying experience, but rather
on the densely textured and unique world that the writings of Aquinas create and
on the form of life that made them possible. This approach, which might be
styled cultural-linguistic or postliberal, is on vivid display in Nicholas Healy's
Thomas Aquinas: Theologian of the Christian Life. A concern of postliberal
Thomists such as Healy is that both neo-Scholasticism and Transcendental
Thomism, in their preoccupation to ground the claims of faith in something
more elemental (truths arrived at through philosophical reason for the former
and universally available experience for the latter), are essentially modernisms,
which allow the content of revelation to be marginalized or muted. But Thomas
Aquinas was not a modern foundationalist and his principal interlocutor was not
the skeptical nonbeliever; hence a new path of interpretation-more in line with
the assumptions and preoccupations of Thomas's time-must be essayed.
It is of supreme importance for Healy that Aquinas was a Dominican, a
member of the Order of Preachers, charged with the task of proclaiming the
good news of Jesus Christ risen from the dead. Though Karl Barth and many
others have complained that Thomas's Christology is incidental to his system,
Healy argues throughout his book that evangelical proclamation is, in point of
fact, the organizing and animating principle of Thomas's intellectual work. He
agrees with Torrell that Aquinas is best read as a Christian spiritual master. Part
of the problem is that contemporary interpreters of the Angelic Doctor, saddled
as they are with foundationalist assumptions, tend to believe that what comes
first is what is most important. Thus because Thomas discusses God in a largely
philosophical way in the first part of the Summa Theologiae and gets to a
consideration of Jesus Christ only in the third part, it appears as though the
rational account provides the ground, setting, and context for the Christology.
Healy suggests that this is to have it precisely backward, to forget that the

BOOK REVIEWS

499

Thomas's masterpiece is structured along the lines of a liturgical procession in
which the most significant players come, not at the beginning, but at the end.
When we follow Healy's examination of Aquinas's Christology, a key feature
emerges with special clarity. In accord with the formula of Chalcedon, Thomas
affirms that divinity and humanity come together in Jesus in a noncompetitive
but asymmetrical manner, since the natures are joined "without mixing,
mingling, or confusion" but are embedded, so to speak, in the unity of the divine
person of the Logos. The creaturely is not overwhelmed, but rather enhanced,
by the proximity of the divine, and this noncompetitiveness is guaranteed
through the power and primacy of the divine. What is ruled out by this
Christology is a view that would either construe God and the creaturely as rivals
or allow God to be in any sense positioned by the creaturely. This dynamic
understanding of Jesus, which contains elements of what contemporary
theologians would call both "high" and "low" Christology, provides, on Healy's
reading, the hermeneutical lens for reading the whole of Aquinas's evangelical
work.
The Christological lens is particularly clarifying in regard to Thomas's
understanding of the relationship between reason and revelation. Healy cites a
line from Etienne Gilson which rather painfully indicates a fatal flaw in the
standard Scholastic interpretation of this issue: "it is natural that [Thomas's] first
question should be about the existence of God. On this problem, however, a
theologian cannot do much more than apply to the philosopher for philosophical
information. The existence of God is a philosophical problem." What Gilson
states, with almost brutal clarity, is the foundationalist view that in regard to its
most basic and essential question-the very being of God-theology is entirely
dependent upon and positioned by natural philosophy. Healy correctly observes
that nothing could be further from the biblical mind of Aquinas. Of course, the
question of God's existence is not first in the Summa Theologiae; instead, it is an
inquiry into the nature of sacra doctrina,the intellectual discipline that Thomas
will be following throughout the work. In the course of that opening quaestio,
Aquinas makes eminently plain that philosophical wisdom is in no sense a
foundation for the theological enterprise, but is instead a means employed by the
theologian in his pedagogical task of leading people (manuductio) toward the
fullness of the revealed mysteries. If one were looking for foundations for sacra
doctrina, one would have to appeal, not to philosophy, but to the knowledge of
God enjoyed by God himself and by the saints, for theology is a subalternate
science, deriving its principles from that higher scientia. Throughout his
writings-and no more clearly than in his commentary on the Gospel of
John-Thomas shows that human reason is itself a participation in the light of
the divine intellect. This means that natural reason could never be construed as
standing outside of divine influence and requiring a correlation to it. The famous
proofs for God's existence, which Gilson bizarrely saw as providing the
philosophical justification for the theological endeavor, are in fact prime
instances of the manuductio that Aquinas spoke of. The finite and fallen mind
needs to be led gradually and in accord with its compromised capacities to see

500

BOOK REVIEWS

the truth of the biblical revelation concerning God. It is this modest (though
pedagogically important) service that the proofs perform. Thus philosophical
reason finds itself positioned and elevated by a higher theological reason in
which it participates, mirroring the relationship between the human and divine
natures in Jesus.
Another area in which the Christological hermeneutic is clarifying is
Aquinas's naming of God. As David Burrell, Fergus Kerr, and many others have
pointed out, the central feature of Thomas's doctrine of God is its radical
apophaticism: we know God as something unknown. This negative theology
appears most clearly in the discussion of God's simplicity. In claiming simplicitas
of God, Thomas is not making a positive statement about the divine nature
(which remains opaque to us in this life); rather, he is removing from the concept
of God anything that smacks of the creaturely: mutability, finitude, dependency,
and, most elementally, participation in a higher cause. What Healy helps us to
see is that this via remotionis flows, not only from the anti-idolatry texts of the
Old Tesatment, but also and especially from the Christological assertions that
Aquinas inherited from the orthodox tradition. Were God a worldly nature, he
would enter necessarily into competition with other finite natures, but since we
know through Jesus that God is capable of uniting himself hypostatically and
noncompetitively with a creature, God must be utterly unlike anything in the
world. He must be known as something unknown. Thus the assertion of the
divme simplicity is ultimately Christological in form and evangelical in purpose.
Whitehead and his innumerable theological disciples have argued that the
immutable and perfect God, not really related to the world, is a philosophical
abstraction at odds with the warm and responsive God implied in the teaching
of the Galilean prophet Jesus. Healy effectively shows how Aquinas derives
God's absolute character not so much from Aristotle as from Jesus, the Incarnate
Lord. Precisely because the God of the Incarnation is not a being in or alongside
the world, he cannot be caught in the nexus of conditioned relationality,
responding to the influences and actions of finite things. Instead, all of God's
relations to the world that he has made are metaphysically prior and primordial,
so that, to give but one example, his knowledge of the universe is not derived
from the universe's existence, but rather vice versa. But this means that the
absolute God is in fact far more intimately connected to creatures (indeed closer
to them than they are to themselves) than any finite and passive supreme existent
could possibly be. The paradox is that Thomas's denial of a "real" relation
between God and the universe is tantamount to his insistence that God is in all
things by essence, presence, and power-and in the most intimate way (intime).
Another implication of this radical divine otherness is the noninvasive
manner in which God grounds created causality. Thomas is absolutely
uncompromising in his claim that God governs the universe and that his
providence extends to particulars. The true God is neither the indifferent prime
mover of Aristotle nor the distant watchmaker of the Deists; instead, he is the
power that stretches from end to end mightily and orders all things sweetly, as
the book of Wisdom puts it. However, this all-embracing divine influence does

BOOK REVIEWS

501

not rule out the real activity of secondary created causes because, once again,
God's activity is modally other and hence noncompetitive. Healy demonstrates
how the aporias concerning God's involvement in the world that have bedeviled
so many modern religious philosophers simply didn't exist for Aquinas, because
he was operating out of a distinctively Chalcedonian metaphysics.
The second part of the Summa Theologiae, which deals with the human
journey back to God, is by far the largest of the three major sections of the work,
and throughout the Middle Ages it was the most copied and commented upon.
Healy joins a number of contemporary Thomists who are attempting to recover
the importance of the treatise on the moral life in the overall context of
Thomas's writing. Here again, the Christological hermeneutic is applied. Though
he borrowed liberally from Aristotle's doctrine of the acquired virtues, Thomas
never held that natural virtue is sufficient unto itself. Rather, it has to be
surrounded and elevated by the theological virtues of faith, hope, and love, since
they alone open the human mind and will to their proper, supernatural end. Just
as philosophy is transfigured by revelation, so the natural virtues are both
maintained and transformed by the theological virtues. In both cases, the
asymmetrical but noncompetitive relation between Christ's natures provides the
theoretical framework.
The organization of material in Healy's book is helpful, and his writing is
both lively and clear. But his greatest contribution is the simple reminder that
Thomas was a Christian theologian, a master of the sacra pagina, and a faithful
member of the Order of Preachers. When that primary evangelical identity is
forgotten, one begins to create the caricatures of Aquinas with which we are all
too familiar.
ROBERT BARRON

Mundelein Seminary
Mundelein, Illinois

The Art of Equanimity: A Study on the Theological Hermeneutics of Saint Anselm
of Canterbury. By EMERY DE GAAL GYuLAI. New York: Peter Lang, 2002.
Pp. 428. $56.95 (paper). ISBN 0-8204-6010-9.

Interpretive studies of the Anselmian corpus are often impeded by their selfpartitioned scope. The argument of Proslogion, for example, will be considered
without the context of the greater treatise; Cur Deus Homo will be presented
independently of Anselm's understanding of reditus or concordia; or the prayers
will be cast as the summit rather than the youth of his spirituality. Such
sequestering of concepts and isolation of treatises ignores the discursive and

502

BOOK REVIEWS

integrated character of the thought of Anselm of Canterbury. Moreover, it
sacrifices the culminative character of his work.
Emery de Gaal Gyulai studies Anselm without these encumbrances. The Art
of Equanimity looks at the full expanse of Anselm's works and finds there a
pervasive (albeit seldom studied) thematic and a consistent method and protocol.
Gyulai then translates those into a deftly prosecuted avenue whereby that saint's
teachings can be approached and penetrated.
The bracing character of Gyulai's analysis is demonstrated even in his book's
earliest pages. While he acknowledges Anselm's debt to Augustine (as does
Anselm himself, of course) and recognizes the influence of Platonic insight,
Gyulai focuses instead on Plotinus as the true antecedent of Anselmian thought.
He reveals more correlation than debt in the link between Plotinus and Anselm,
but he mines their intersection effectively and purposefully, creating a
prosperous and persuasive alternative grounding for Anselmian thought.
The other influence emphasized by Gyulai is Benedictine monasticism. This,
too, provides for a rich interpretive elaboration of Anselm. Scholars commonly
provide lip-service to Anselm's monastic allegiance, but rarely is its role specified
or delineated so persuasively. Gyulai displays an impressive familiarity with the
Benedictine rule and life, placing Anselm solidly and congenially in its context.
This makes a significant contribution to his explicandum of Anselm. By allowing
Anselm his Benedictine voice (cf. p. 14), Gyulai secures an essential key to what
he terms the "via Anselmi." Benedict is cast as the root of both deed and thought
in Anselm.
According to Gyulai, Anselm sees a "finite human person grounded in an
infinite origin" (16). Finite and infinite are distinct, yet the finite is not
inherently "unrelated or separate." This, by Gyulai's appraisal, allows
perspective; it "permits one to behold the essential in life" (17). That
understanding is fundamental to the argument that follows. It figures into that
whole concept of 'necessary conclusions' (Anselm's necessariis rationibus) that
serves as the core dynamic of Anselmian reason. Gyulai's approach employs
strong metaphysical consciousness and integration. Unlike the approach
embraced in modernity (at least as depicted by Gyulai), this mindset is responsive
and indebted to an immanent Lord. It recognizes and accepts the reality of truth
and thus provides for "humanity's greater authenticity" (21).
By careful distinctions and insightful deductions, Gyulai installs this as the
foundation of the Anselmian hermeneutic. In particular, he emphasizes that
Anselm's method disallows compartmentalization. Philosophy and theology are
not disparate, neither are they divided into subdisciplines. Their integration is
fundamental to the insight they allow, a character that reflects humanity's
alignment with the Lord: just as divinity has integral oneness, so does properly
oriented thought. Indeed, Gyulai suggests, it is reason and faith that are enlisted
by Anselm, not philosophy and theology. That is an important distinction.
Perspective is fundamental in Anselm. Repeatedly, he imposes his own
definitions and specifications on his subjects, ensuring that they are aligned with
truth (by his understanding of it). Gyulai conveys an appealing excitement as he

BOOK REVIEWS

503

discusses the vitality of this vision, invariably setting Anselm's insights (according
to the peculiar grounding he provides) within the provisions of Christian dogma.
Here Gyulai's emphasis on the correlation with Plotinus proves especially
fecund. The author exposes a "congeniality" that exists between Plotinus and
Anselm (discussed most explicitly in chapter 2) that lets each lend depth and
exposition to the other. At the core of their intersection, Gyulai maintains, is
their insistence that a person's reason is "sustained by the object of its thinking"
(43). Both Plotinus and Anselm, he suggests, recognize a divine predication in
truth. For them, "everything that [comes] forth from God is destined also to be
traceable back to its origin" (45). Anselm's continere is very much Plotinus's
synechein;both terms reflect the indebtedness and dependence that weighs upon
human beings in relation to God.
That relationship is a recurring theme in Anselm's thought, and Gyulai sees
it as indicative of a distinctly mystic point of view. According to Anselm, a
person identifies with the principle itself. Each individual is grounded in the
One. He would have being and Being intersect; "an access to the One is opened
in spite of all essential differences" (52).
Gyulai also addresses Anselm's correlation with Scripture, patristic sources
(especially Gregory of Nyssa and Pseudo-Dionysius), and other mediaevals, but
Benedict remains his most profound alignment. Gyulai mines Anselm's
compatibility with his monastic predecessor, using it as a prime element in the
Anselmian hermeneutic. Benedict provides context for Anselm's life and thought
(cf. the discussion in chapter 3). Moreover, the congruence with Benedict colors
his approach to truth and to the person's life of truth. Regula Benedicti's vision
of an existence wherein God is glorified, articulated, and reflected-in all that
is and in all that is done-is fundamental to Anselm. He embraces the absolute
character of Benedictine life where (as Gyulai articulates it), "No nook is left for
profanity to seek refuge from God" (91).
Gyulai develops the Benedictine insight and its relevance to Anselm in
considerable detail. His point, realizing how integrally Anselm adopts the
monastic founder's perspective, is that Benedict endowed this later monk-abbotbishop with vital confidence in a mysticism that disallows any "hiatus between
idea and reality, between idea and image" (95). In Anselm's hands, where there
is little indulgence of gray areas, that requires a full and comprehensive
correlation with divinity. Gyulai convincingly portrays Anselm as profoundly
influenced by the practicability that the cloister assigns to this ambition. This is
a "continuation" of Plotinus, he suggests, proposing an intelligent, active, willed,
purposeful correlation that · accents "the divine in the human being" while
envisioning "already in his terrestrial existence the heavenly Jerusalem" (99). In
this, Gyulai differentiates the vision shared by Benedict and Anselm from that
proposed in mainstream Scholasticism. In particular, he notes that for them
experientia is necessarily part of the work at hand; the scientia of later
Scholastics cannot command the field autonomously. In the Benedictine standard
"ora et labora," Gyulai finds the "hermeneutical locus of the monastic mind"
(101); he identifies it as a pivotal ideal for both Benedict and Anselm, and the

504

BOOK REVIEWS

core element in separating monastic theology from ordinary dogmatic theology.
Truth is lived as well as known. By that standard, Gyulai contends, Anselm's
monasticism functions comprehensively, that is, in attitude, aspiration, character,
and execution.
The importance of this understanding in explicating Anselm's outlook and
thought is profound. It provides him with a hermeneutic that, in a sense, pursues
the divine character, presence, and honor (to use Anselm's term) in all that is.
Recognizing in Anselm this mystic orientation allows Gyulai to render his
hermeneutics with fresh and laudable nuance and precision. In particular, he
recognizes that Anselm's thought cannot profitably be grasped independently of
the reality of divinity. All thinking is for Anselm "a meditation on the One"
(114).

This Anselmian insight is nurtured, explicated, and developed by Gyulai
through fourteen chapters. He makes his argument effectively, calling upon his
comfortable command of the full corpus of Anselm's works and his able and
confident grasp of how the monastic experience is elemental in a monk's
definition of self and of the selfs ambition. In consequence, Gyulai's study
should inform and enrich both scholars and students. This is a book of value and
importance. As Gyulai plumbs Anselm's integrated life and teaching, he invests
in that doctor's tuition and perspective renewed life and vigor.
Because of the generous merit of Gyulai's text, this book's few flaws seem
especially peccable. The notes, for example, appear not to have been perfected
as conscientiously as was the text (e.g., indicating "Constable Giles" instead of
"Giles Constable" [91 n. 9]). Throughout this volume, there is a distracting and
sometimes disorienting failure to italicize passages in other languages. References
to Regula Benedicti give the chapter number, but never the verse. There is
inconsistency in giving translations, too: Latin is sometimes translated, but often
not; Greek passages are translated, but German and French seldom are. Such
fluctuations disrupt the flow of Gyulai's narrative. There is also an unfortunate
tendency to populate this text with unapplied references. Especially in the
earliest chapters, multiple invocations of philosophers and others are injected
without delineation or specification of their relevance.
The publisher is at fault, too, for having imposed some questionable
production standards. In particular, the microscopic typeface works against
Gyulai's text. Spacing-or rather, its inadequate employment-gives a jumbled,
crowded appearance. Chapters begin at the top of the page and are not set off
by size, placement, or character. The lack of italics when rendering non-English
words and passages (as mentioned above) confuses inference and substance. The
absence of headings atop each page also limits navigation. Aesthetic concerns
generally are ignored in both printing and presentation.
Gyulai's argument in this book is overwhelmingly astute and precisely
rendered. Indeed, he has a singular ability to use exactly the right word (e.g., his
use of dialecticalto explain Anselm's view of the "relationship between justice
and mercy" [191]). His seventh chapter (on soteriology) deserves special

BOOK REVIEWS

505

acknowledgment as a model of precision and penetration in handling the
Anselmian insight.
In The Art of F.quanimity Emery de Gail Gyulai has made a significant
contribution to the study of Anselm's thought. He affords the dimension as well
as the substance whereby the Anselmian corpus can rightly be exposed to new
generations of inquirers.
PASCHAL BAUMSTEIN, 0.S.B.

Belmont Abbey
Belmont, North Carolina