What Do God and Creatures Really Do in an Evolutionary Change? Causal Analysis of Biological Transformism from the Thomistic Perspective

Abstract

Many enthusiasts of theistic evolution willingly accept Aquinas' distinction between primary and secondary causes, to describe theologically "the mechanics" of evolutionary transformism. However, their description of the character of secondary causes in relation to God's creative action oftentimes lacks precision. To some extent, the situation within the Thomistic camp is similar when it comes to specifying the exact nature of secondary and instrumental causes at work in evolution. Is it right to ascribe all causation in evolution to creatures-acting as secondary and instrumental causes? Is there any space for a more direct divine action in evolutionary transitions? The article offers a new model of explaining the complexity of the causal nexus in the origin of new biological species, including the human species, analyzed in reference to both the immanent and transcendent orders of causation. Formulated within the framework of Aristotelian-Thomistic philosophy and theology, it should be helpful for all those who refer to secondary causation of creatures in theological reflection on evolution.

Full text

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What Do God and Creatures Really Do in an Evolutionary Change?
Causal Analysis of Biological Transformism from the Thomistic Perspective
Mariusz Tabaczek, O.P.
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This is the final draft of an article published in the 2019 summer issue of ACPQ:
https://www.pdcnet.org/collection-
anonymous/browse?fp=acpq&fq=acpq%2FVolume%2F8907%7C93%2F8997%7CIssue%3A%2
03%2F
Abstract:
Many enthusiasts of theistic evolution willingly accept Aquinas’ distinction between primary and
secondary causes, to describe theologically “the mechanics” of evolutionary transformism.
However, their description of the character of secondary causes in relation to God’s creative action
oftentimes lacks precision. To some extent, the situation within the Thomistic camp is similar when
it comes to specifying the exact nature of secondary and instrumental causes at work in evolution.
Is it right to ascribe all causation in evolution to creatures – acting as secondary and instrumental
causes? Is there any space for a more direct divine action in evolutionary transitions? The article
offers a new model of explaining the complexity of the causal nexus in the origin of new biological
species, including the human species, analyzed in reference to both the immanent and
transcendent orders of causation. Formulated within the framework of Aristotelian-Thomistic
philosophy and theology, it should be helpful for all those who refer to secondary causation of
creatures in theological reflection on evolution.
1
Mariusz Tabaczek, OP, is a Dominican friar and priest. He holds PhD in systematic and philosophical
theology from Graduate Theological Union in Berkeley, California, and S.T.L. in dogmatic theology from the
University of Adam Mickiewicz in Poznan, Poland. He is affiliated with the Thomistic Institute in Warsaw,
Poland and teaches in the Dominican College of Philosophy and Theology in Cracow, Poland, and the
Pontifical Theological Faculty in Warsaw, Poland. His areas of expertise include systematic theology, theology
of divine action, science and theology dialogue, philosophy of science, philosophy of biology, philosophy of
causation, contemporary metaphysics in analytical tradition, classical and new Aristotelianism. He may be
contacted by e-mail: mtabaczek@gmail.com.

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Key words:
Aquinas, Aristotle, Divine action, Evolution, Essence and existence, Hylomorphism, Instrumental
causes, Principle of proportionate causation, Secondary causes
Throughout all our efforts, in every dramatic struggle between old and new
views, we recognize the eternal longing for understanding: the ever-firm
belief in the harmony of our world, continuously strengthened by increasing
obstacles to comprehension.
Albert Einstein and L. Infeld, The Evolution of Physics
Many theologians who support the position of theistic evolution willingly accept Aquinas’s
distinction between primary and secondary causes, to describe theologically “the mechanics” of
evolutionary transformism. Their description of the character of secondary causes in relation to
God’s creative action, however, oftentimes lacks precision. It is not entirely clear how they
understand secondary causation of creatures and how they relate it to God’s action in evolutionary
changes. Moreover, their tendency to marry divine concurrence, defined in terms of the distinction
between primary and secondary causes, with the particular version of the free-will defense
argument—which entails God’s free decision to limit his divine power to allow for creaturely self-
determination (including human free will)—seems to be self-contradictory.
The situation within the Thomistic camp is similar, to some extent, when it comes to
specifying the exact nature of secondary and instrumental causes at work in evolution. Important
questions arise whether it is right to ascribe all causation in evolution to creatures—acting as
secondary and instrumental causes—and whether there is any space for a more direct divine action
in evolutionary transitions. This article offers a new model of explaining the complexity of the
causal nexus in the origin of new biological species, analyzed in reference to both the immanent
and transcendent orders of causation. Formulated within the framework of Aristotelian-Thomistic
philosophy and theology, it should prove helpful for all those who refer to the secondary causation
of creatures in theological reflection on evolution.
The article consists in ten sections. The first two describe references and understanding of
secondary and instrumental causation in theistic evolution outside and within Thomistic
theological circles. The following three sections offer an elementary introduction to the principles
of Aristotelian ontology and metaphysics, presentation of the already proposed model of
metaphysics of evolutionary transformism, and a reflection on Aquinas’s discovery of esse and its
influence on his definition of creatio ex nihilo and of what we tend to call nowadays creatio continua.

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The intermediate section that precedes the main argument of the article explains the principles of
our interpretation of Aquinas’s theology in the context of the debate on the possibility of creation
through biological evolution. The next two sections present our new constructive model of
concurrence of divine and natural causes in evolutionary transformations. The second to last
section addresses the difficult question concerning the unity of the nexus of causes engaged in an
evolutionary change. The article closes with a short reflection on the theological advantages and
consequences of the proposed model of divine and creaturely causation in evolution.
I. Secondary Causation in Theistic Evolution Outside of Thomistic Circles
Theistic evolution, defined as the position striving to reconcile Christian faith with
evolutionary biology, is in fact a collection of views ranging from those that reluctantly consent to
the truth of evolutionary theory on the grounds of its scientific credibility, to those that embrace
with great enthusiasm both developmental and evolutionary worldviews. Hence, the variety of
theologians who may be classified as proponents of theistic evolution goes from more conservative
or even fundamentalist thinkers such as Benjamin B. Warfield (1851-1921) to radically progressive
adherents of transformism such as Pierre Teilhard de Chardin (1881-1955) for whom the concept of
evolutionary advance become a foundation for his comprehensive epistemology, metaphysics and
spirituality. Between these two extreme positions, Ted Peters and Marty Hewlett list a number of
thinkers whose ideas gradually descend or ascend (depending on the opinion of their reader) from
one end of the spectrum to the other. They mention: a cell biologist Kenneth Miller, a biochemist
and theologian Arthur Peacocke (1924-2006), systematic theologians Denis Edwards and John
Haught, physicist and theologian Robert John Russell, and systematic theologian Philip Hefner.
2
The analysis of convergences and divergences between these theologians concerning deep
time, natural selection and teleology, common descent, divine action, and theodicy shows that the
majority of them value the concept of secondary causation.
3
They seem to find attractive the idea
2
See Ted Peters and Martin Hewlett, Evolution from Creation to New Creation: Conflict, Conversation, and
Convergence (Nashville: Abingdon Press, 2003), chapter 6, 115-57.
3
The idea of primary/secondary causation is not so important for de Chardin who sees divine action as
uniformitarian, yet not in a deistic sense (God initially selects the laws that are operative through cosmic and
evolutionary history and withdraws from any further individual interventions) but rather as an ongoing
pantheistic divine guidance of evolution, internal to nature as it is internal to divine life. See Pierre Teilhard
de Chardin, The Phenomenon of Man (New York: Harper, 1959). Philip Hefner seems to side with de Chardin
on this issue. See Philip J. Hefner, The Human Factor: Evolution, Culture, and Religion (Minneapolis: Fortress
Press, 1993). The position of Kenneth Miller on divine action is close to deism (even if he strives to avoid it).
He does not point toward anything God could do within the natural world, which seems to make him

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of God as primary cause working through the secondary causation of his creatures, as it enables
them to assert the autonomy of both nature and God, working on separate yet connected planes of
reality. A closer analysis of their use of the distinction between primary and secondary causation,
however, reveals a lack of precision in defining it. Warfield uses it primarily to explain the
simultaneously divine and human origin of the Holy Scripture and only secondarily as a base for
his theological incorporation of evolutionary theory.
4
Others seem to compromise the concept of
primary/secondary causation by joining it to the particular version of the free-will defense
argument, which entails God’s free decision to limit his divine power to permit creaturely self-
determination, including human free will.
5
This tendency may be clearly seen in the position of
Peacocke. While he does speak about God making “things make themselves” and the interplay of
order and chance as secondary causes working in nature, Peacocke writes extensively about God’s
self-limitation in his omnipotence and omniscience as a condition for the coming into existence of
free self-conscious human beings and finds a new level of God’s presence in creation expressed in
his sharing the world’s sufferings.
6
The idea of self-limitation of God—a fellow sufferer who thus,
affected by the world, shares in the very life of his creatures—is even more transparent in the
versions of theistic evolution offered by Denis Edwards and John Haught. They both perceive God
as engaged in self-restraint and self-removal, i.e., creating through letting-be.
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responsible only for its existence. See Kenneth R. Miller, Finding Darwin’s God: A Scientist’s Search for
Common Ground Between God and Evolution (New York: Cliff Street Books, 1999).
4
See Benjamin Breckinridge Warfield, Evolution, Scripture, and Science: Selected Writings, ed. Mark A. Noll
and David N. Livingstone (Grand Rapids: Baker Books, 2000), 56-57.
5
The free-will defense is a logical argument developed by Alvin Plantinga in response to the challenge
formulated by John Leslie Mackie, who claimed that the key attributes of the God of Christian theism (his
omniscience, omnipotence, and omnibenevolence) are logically incompatible with the existence of evil (see
Alvin Plantinga, God, Freedom, and Evil [Grand Rapids, MI: Eerdmans, 1977], chapter 4; John Leslie Mackie,
“Evil and Omnipotence,” Mind 64 [1955], 200-212). Plantinga’s original argument emphasized the moral value
of human free will as a justified reason for God’s permitting the existence of evil. The same argument from
the defense of human free will (accompanied by the more general concept of creaturely self-determination),
was later used to argue in favor of divine self-limitation in creation of the universe.
6
See Arthur Robert Peacocke, Theology for a Scientific Age: Being and Becoming—Natural, Divine, and Human
(Minneapolis: Fortress Press, 1993), 99-134.
7
See Denis Edwards, The God of Evolution: A Trinitarian Theology (New York: Paulist Press, 1999); and John
F. Haught, God After Darwin: A Theology of Evolution (Boulder, CO: Westview Press, 2000). Any logically-
coherent theory that includes the claim that God limits his own power uses the term “God” in a sense quite
different from that of Aquinas, for whom God is, of necessity, omnipotent. This will become more apparent
in the latter sections of this article. The use of the term “God” in Peacocke, Edwards, and Haught, seems to
be nearer to the one proposed by Hegel or Whitehead than to Aquinas’s. See Mariusz Tabaczek, “Hegel and
Whitehead: In Search for Sources of Contemporary Versions of Panentheism in the Science–Theology
Dialogue,” Theology and Science 11 (2013): 143–61.

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Peters and Hewlett note that free-will defenders seem to contradict their own choice of
applying the distinction between primary and secondary causation in their versions of theistic
evolution. In fact, they “tacitly and perhaps unintentionally reject secondary causation, presuming
rather that divine power and creaturely freedom belong on the same plane. … The fallacy
presupposes a fixed pie of power. According to the fixed pie image, if God gets a big slice then
creation gets a proportionately smaller slice. If God would be all-powerful, then creation would be
totally powerless.”
8
This criticism rightly shows that many contemporary theologians, who strive to
reconcile faith with the scientific view of the universe, tend to speak about divine action in the
world in univocal terms, locating it on the same ontological level as the causation of contingent
creatures.
Robert John Russell tries to avoid this difficulty. In doing so, however, he seems to be getting
close to the other extreme of the spectrum. Acknowledging the importance of secondary causation
of creatures, he speaks about the direct divine action on the quantum level as the origin of
evolutionary changes. He claims that this type of divine action is objective and non-interventionist
(NIODA = non-interventionist objective divine action), since—according to the Copenhagen
interpretation of quantum mechanics—we cannot expect natural causes to operate in these events,
as they are ontologically indeterminate. Nevertheless, Russell’s version of theistic evolution may
still be in danger of univocally predicating causation of God and creatures, since he suggests that
God withdraws his causal activity with the advent of consciousness and human free will. This might
suggest he needs to “make a space” for specifically human action.
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II. Secondary Causation in Theistic Evolution Within Thomistic Circles
Within the Thomistic theological camp the situation looks different. Proponents of theistic
evolution from among Thomists carefully avoid the mistake of the univocal predication of God’s
and creatures’ causal activity. On the one hand, they do side with Aquinas’s assertion that “God’s
immediate provision over everything does not exclude the action of secondary causes; which are
the executors of His order.”
10
Since God as the Creator has gifted every creature with its proper
8
Peters and Hewlett, Evolution, 130-31, 143.
9
See Robert J. Russell, Cosmology from Alpha to Omega: The Creative Mutual Interaction of Theology and
Science (Minneapolis: Fortress Press, 2008), chapters 5-6, 151-225.
10
ST I, q. 22, a. 3, ad 2. See also ST I, q. 19, a. 6, ad 3; q. 19, a. 8, co.; q. 23, a. 5, co.; q. 105, a. 5, ad 2; I-II, q. 10, a.
4, ad 2; Etienne Gilson, The Christian Philosophy of St. Thomas Aquinas (New York: Random House, 1956),

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causality, according to its nature, his influence cannot interfere with this causality, but must rather
be its source. On the other hand, they emphasize that, while we can say that a particular natural
effect comes to be through the combined agencies of God and the natural agent, we must remember
that the same effect is not attributed to a natural cause and to divine power in such a way that it is
partly done by God, and partly by the natural agent; rather, it is wholly done by both, according to a
different way, just as the same effect is wholly attributed to the instrument and also wholly to the
principal agent.
11
Thus, Thomistic advocates of theistic evolution acknowledge that, metaphysically speaking,
the divine action of a transcendent God does not belong to the same order of causation as that of
his creatures. Even if “all created things, so far as they are beings, are like God as the first and
universal principle of all being”
12
immanently present in their operations, the causation of the
Creator infinitely transcends causation of all contingent creatures. The influence of the first cause
is therefore not only more intense, so that we can assert with Aquinas that “God is more especially
the cause of every action than are the secondary agent causes.”
13
We must also realize that God’s
agency belongs, in its essence, to an entirely different ontological and metaphysical order of
causation. Consequently, Thomistic evolutionists do not see any need of introducing divine self-
limitation or the self-restriction of God’s attributes of omnipotence and omniscience, to explain the
indeterministic character of some occurences in nature, and the phenomenon of human free will.
Moreover, Thomistic theology offers one more important distinction concerning causal
efficiency that might be helpful in explaining the position of theistic evolution. The passage from
Aquinas’s Summa contra gentiles quoted above, in which he attributes causal effects observed in
nature to the agency of both God and creatures, introduces a further distinction in the realm of
secondary causes. Some of them act according to their natural dispositions, while others produce
effects beyond their capacities. Aquinas classifies the latter as instrumental causes and emphasizes
their dependence on principal causes for their operation (e.g., an ax in the hand of a lumberjack).
In other words, instrumental causes can be classified as a special kind of secondary causes, since
every cause that acts under the influence of another is a secondary cause. At the same time, a cause
176, 182-84; Rudi A. te Velde, Participation and Substantiality in Thomas Aquinas (Leiden, New York, Köln:
E.J. Brill, 1995), 170-75.
11
SCG III, 70, no. 8. “[J]ust as it is not unfitting for one action to be produced by an agent and its power, so it
is not inappropriate for the same effect to be produced by a lower agent and God: by both immediately,
though in different ways” (SCG III, 70, no. 5).
12
ST I, q. 4, a. 3, co.
13
SCG III, 67, no. 5. See also ST I, q. 21, a. 4, co.; q. 36, a. 3, ad 4; Q. de ver. q. 5, a. 9, ad 10; Q. de pot. q. 3, a. 7,
co.

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that produces an effect exceeding its natural capacity should be regarded as an “instrumental
secondary cause (causa secunda instrumentalis)” (ST I, q. 45, a. 5, co.).
The distinction between secondary and instrumental causes may be applied to the
theological explanation of cases of the origin of new species, in which parental organisms of species
S1 give an origin to the first organism belonging to the new species S2, acting thus—in some
respect—both in accordance with and beyond their own causal dispositions, i.e., as both secondary
and instrumental causes in the hands of God. However, Thomistic proponents of theistic evolution
oftentimes do not seem to engage in more detailed analysis of divine action in the coming to be of
new species. Their argumentation seems to be limited to a very careful presentation of Aquinas’s
understanding of creation and his distinction between primary causation of God and secondary
(and instrumental) causation of his creatures, followed by a general reference of these principles to
evolutionary transformism. N. Luyten, for instance, commenting on causality in evolution, states:
We know of enough cases where we meet a complex intertwined causality, and where a double
efficiency does not simply stand beside each other, but works in a subordinated relationship. The
classic doctrine of instrumentality has sufficiently studied the nature of such a causal subordination.
Hence it is conceivable that, in the evolutionary process too, we must admit such a coordination of
factors, in which a transcendent factor would cooperate not simply from without but from within
with the evolutionary factors at work in the animal series. This means that the transcendent factor
must at the same time be immanent so as to fuse innerly, as it were, with the purely immanent
causality of the antecedent.
14
A little bit more specific is the explanation provided by Jacques Maritain who, commenting on the
passage from one ontological species to the next higher one, refers to the transcendent influence of
the first cause, whose
existence-giving influx …, passing through created beings and using them as instrumental causes,
was able—and is still able—to heighten the vital energies which proceed from the form in the
organism it animates, so as to produce within matter, I mean within the germ-cells, dispositions
beyond the limits of that organism’s specificity. As a result, at the moment of generation a new
substantial form, specifically “greater” or more elevated in being, would be educed from the
potentiality of matter thus more perfectly disposed.
15
Explanations offered by other Thomists—although generally correct and fitting within the
orthodoxy of Aquinas’s system of philosophy and theology (with some necessary revisions of its
basic principles)—are sometimes even more general when it comes to a precise explanation of the
exact nature of causal agency of God and creatures in an evolutionary change. They do address
14
N. Luyten, “Evolutionisme En Wijsbegeerte,” Tijdschrift Voor Philosophie 1 (1954), 30, after Joseph Donceel,
“Causality and Evolution,” New Scholasticism 39 (1965), 301-302.
15
Jacques Maritain, The Range of Reason (New York: Scribner, 1952), 38.

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numerous questions concerning philosophies of evolution, randomness and order, design, species,
intrinsic teleology, or creation and divine providence in evolutionary changes in general and in
evolution of man in particular.
16
They also provide, as we will see, a possible metaphysical
“mechanism” of transformism. At the same time, however, they do not seem to clarify enough what
exactly God does in an evolutionary transition and whether his causal power is entirely delegated
to the secondary and instrumental causation of creatures. Such is the weakness of the otherwise
quite thorough and informative works of Raymond J. Nogar or William Carroll on the theological
aspects of evolution.
17
The purpose of this article is to fill this lacuna by developing a model explaining the relation
and concurrence of divine action and the causality of creatures in evolutionary changes. To make
this model understandable and accessible to our reader, we need to begin with a brief introduction
to the principles of Aristotelian ontology and metaphysics, followed by the already proposed
explanation of metaphysics of evolutionary transformism and a reflection on Aquinas’s discovery
of esse and its influence on his definition of creation.
III. Aristotelian Hylomorphism and the Metaphysics of Change
The departure point of our analysis is the ancient metaphysics of Aristotle, whose thought—
transmitted by Arabic thinkers—had been rediscovered in the Middle Ages, in the cradle of the
Western Academia in Paris. It was Aristotle—whom Aquinas would simply call the Philosopher with
the capital “P”—who introduced the theory of hylomorphism, i.e., the most fundamental
metaphysical composition of all material entities of matter and form. When we say “matter and
form” (ὕλη and μορφή), however, we must realize—especially in the context of the contemporary
16
See for example: Travis Dumsday, “Is There Still Hope for a Scholastic Ontology of Biological Species?,” The
Thomist 76 (2012), 371-95; Jacques Maritain, Untrammeled Approaches (Notre Dame, IN: University of Notre
Dame Press, 1997), chapter VI: On the Philosophy of Nature (I) – Toward a Thomist Idea of Evolution, 85-131;
Antonio Moreno, “Finality and Intelligibility in Biological Evolution,” The Thomist 54 (1990), 1–31; Ernan Mc
Mullin, “Evolution and Special Creation,” Zygon 28 (1993), 299–335; Raymond J. Nogar, “From the Fact of
Evolution to the Philosophy of Evolutionism,” The Thomist 24 (1961), 463-501.
17
See Raymond J. Nogar, The Wisdom of Evolution (New York: Doubleday, 1963). William E. Carroll, “At the
Mercy of Chance? Evolution and the Catholic Tradition,” Revue Des Questions Scientifiques 177 (2006): 179–
204; William E. Carroll, Creation, Evolution, and Thomas Aquinas,
https://www3.nd.edu/~afreddos/courses/43150/carroll3.htm (retrieved on February 22, 2018); William E.
Carroll, “Creation in the Age of Modern Science,” Tópicos 42 (2012): 107–24. See also Nicanor Austriaco, “How
Does God Create Through Evolution?” in Nicanor Pier Giorgio Austriaco et al., Thomistic Evolution: A
Catholic Approach to Understanding Evolution in the Light of Faith (Tacoma, WA: Cluny Media, 2016), 192-
200.

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neo-hylomorphism in analytic metaphysics—that these are not physical matter and geometrical
shape that Aristotle has in mind (at least not in the very core of his definition of hylomorphism).
18
While introducing his theory of four causes Aristotle does list the first two of them as:
material and formal.
19
What is crucial concerning his philosophical understanding of matter,
though, is its irreducibility to basic chunks of physical stuff (elementary particles) out of which
things are made. Although one may find it difficult to grasp in the oft-cited quotations from Physics
and Metaphysics, for Aristotle matter is the most basic metaphysical principle of potentiality, i.e.,
primary matter (πρώτη ὕλη), underlying nature (ὑποκείμενοη φύσις), or primary substratum
(πρῶτον ὑποκείμενον), that persists through all changes that a given substance can be exposed to.
As something that constitutes the very possibility of being a substance, it should be distinguished
from secondary (proximate) matter, which is perceptible to our senses and quantifiable.
20
Understood this way, primary matter is real and exists, even if not with its own independent act of
existence, but with the existence of a substance. Moreover, as pure being-in-potency, primary
matter underlies each and every substance, remaining a principle of continuity in the process in
which one substance (S1) becomes another substance (S2). Thus, in the occurrence of the change of
substance S1 to substance S2, we are not dealing with either a mere reorganization of elementary
18
For critical presentation and evaluation of contemporary neo-hylomorphic positions see Mariusz Tabaczek,
Emergence. Toward a New Metaphysics and Philosophy of Science (South Bend, IN: University of Notre Dame
Press, 2019), chapter 6.
19
“In one sense, then, (1) that out of which a thing comes to be and which persists, is called ‘cause’, e.g. the
bronze of the statue, the silver of the bowl, and the genera of which the bronze and the silver are species. In
another sense (2) the form or the archetype, i.e. the statement of the essence, and its genera, are called ‘causes’
(e.g. of the octave the relation of 2:1, and generally number), and the parts in the definition” (Phys. II, 3 [194b
24-28]).
“‘Cause’ means (1) that from which, as immanent material, a thing comes into being, e.g. the bronze is the
cause of the statue and the silver of the saucer, and so are the classes which include these. (2) The form or
pattern, i.e. the definition of the essence, and the classes which include this (e.g. the ratio 2:1 and number in
general are causes of the octave), and the parts included in the definition” (Meta. V, 2 [1013a 24-29]).
20
This becomes clear in the following passages from Physics and Metaphysics: “The underlying nature
(ὑποκείμενοη φύσις) is an object of scientific knowledge, by an analogy. For as the bronze is to the statue, the
wood to the bed, or the matter and the formless before receiving form to any thing which has form, so is the
underlying nature to substance, i.e. the ‘this’ or existent” (Phys. I, 7 [191a 8-12]). “The matter comes to be and
ceases to be in one sense, while in another it does not. As that which contains the privation, it ceases to be in
its own nature, for what ceases to be—the privation—is contained within it. But as potentiality it does not
cease to be in its own nature, but is necessarily outside the sphere of becoming and ceasing to be. (…) For my
definition of matter is just this—the primary substratum (πρῶτον ὑποκείμενον) of each thing, from which it
comes to be without qualification, and which persists in the result” (Phys. I, 9 [192a 25-33]). “By matter I mean
that which in itself is neither a particular thing nor of a certain quantity nor assigned to any other of the
categories by which being is determined … the ultimate substratum is of itself neither a particular thing nor
of a particular quantity nor otherwise positively characterized; nor yet is it the negations of these, for
negations also will belong to it only by accident” (Meta. VII, 3 [1029a 20-21, 24-25]).

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particles (this would not be a substantial but an accidental change) or a total annihilation of S1 and
coming to be out of nothing of S2. Rather, due to primary matter as principle of potentiality
underlying all existing substances, we observe the continuity of the process of S1 changing into S2.
Concerning formal cause, Aristotle situates himself in a radical opposition to the
transcendental character of Ideas in Plato. For him forms do not exist in a supernatural realm, nor
are they imitated imperfectly by the mundane reality. To the contrary, according to Aristotle forms
must be in things, determining their actuality. This becomes clear from the quotations from Physics
and Metaphysics cited above. In both passages, Aristotle, speaking of formal causality, uses the term
“ὁ λόγος τοῦ τί ἦν εἶναι,” which Gaye translates as “the statement of the essence,” and Ross as “the
definition of the essence.”
21
Form is for him a principle of each existing substance that makes it to
be the particular kind of thing it is – a metaphysical principle of actualizing (determining) a pure
possibility-of-being (primary matter) to be a concrete substance. Even if Aristotle uses other terms
to describe formal cause—including μορφή and εἴδος, which translate as “shape” and
“appearance”—it is “ὁ λόγος τοῦ τί ἦν εἶναι,” that gives us the best grasp of what Aristotle meant by
substantial form.
22
As an actualizing factor, it becomes a principle of novelty and an active source
of change in causal processes. Hence, even if in a process of substantial change from S1 to S2 primary
matter does not change, we distinguish S1 and S2 as separate substances due to different forms that
inform primary matter in them and are educed from its potentiality. Moreover, substantial form is
not only responsible for actualizing primary matter in particular kinds of things. Together with
accidental forms—which are responsible for secondary properties of a given substance (such as its
size or color) and may change without it changing its identity—substantial form disposes primary
matter to particular substantial changes and not others, such that a wooden log put into a fire
changes into ash and not into a bird.
23
It is true that material and formal causes—which Aristotle found necessary for an
explanation of the very nature of living and nonliving things, as well as their stability and change—
may seem to the contemporary researcher of nature, at first glance, abstract, incomprehensible,
21
Phys. II, 3 (194b 26); Meta. V, 2 (1013a 27).
22
Note that it is μορφή that gave the origin to the term “hylomorphism,” despite the fact that it is not the
most accurate depiction of what Aristotle understands by formal cause.
23
Consequently, Aristotle recognizes an ascending gradation in the perfection of beings in nature. On his
scala naturae we can observe a gradual crescendo from non-living, through plant and animal, to human
forms, which is an outcome of a proper disposition of primary matter to be informed by a proper kind of
substantial form: “[N]ature passes from lifeless objects to animals in such unbroken sequence, interposing
between them beings which live and yet are not animals, that scarcely any difference seems to exist between
two neighbouring groups owing to their close proximity” (Par. an. IV, 5 [681a 12-15]).

11
difficult to defend, or even unnecessary and spurious. The situation changes, however, once we
refer Aristotelian principles to the modern theory of information with its emphasis on the
immaterial nature of information propagating in the universe since the initial Big Bang, and
quantum mechanics with its thesis that each elementary particle is not so much a physical object
but a fluctuation in the potential of the quantum field (a local coherence of quantum vacuum).
24
Even if there is no direct reference between these concepts, it seems that the contemporary theory
of information and contemporary physics bring us closer to Aristotle’s philosophy of nature and his
metaphysics than ever, since it was rejected with the advent of the scientific revolution in the
seventeenth century. Hence, it seems the idea of information in-forming all existing entities in the
universe, and the concept of quantum field underlying the very fabric of the cosmos can be—with
all caution and awareness of methodological differences between natural science and
metaphysics—related to formal and material causes as defined by Aristotle.
IV. Hylomorphic Metaphysics of Evolutionary Transformations
The heuristic value of hylomorphism goes even further. Offering a crucial metaphysical
background for the ontology of irreducibly complex biological systems, it also becomes a fitting
metaphysics for the philosophical analysis of an evolutionary transformation. In reference to
Moreno and O’Rourke, we may describe each evolutionary change as a series of accidental changes
in the structure of genetic material (DNA), affecting the disposition of primary matter in-formed
(actualized) by substantial forms of organisms in a given lineage of a species S1, and leading to a
precise instant at which the primary matter underlying the egg and the sperm coming from parental
24
Although the history of the term “information” goes all the way back to ancient Greece, philosophy of
information as a separate discipline is rather new. The context of its origin was the modern empirical theory
of knowledge, as well as mathematical concepts of information and related to them new information
technologies which were developed in the twentieth century. The first challenge that philosophy of
information faces is the definition of its main point of interest. It becomes obvious that the popular definition
of “information” as the equivalent of some portion of data, code, or text—written, sent, received, or
manipulated in a given medium—is not sufficient. An attempt at specifying its nature at the meta-level of
description gave an origin to a set of definitions concentrating on its quantitative (theories of Fisher,
Shannon, Kolmogorov, or quantum theory of information), or qualitative aspects (theory of information as
the state of a subject or the semantic theory of information offered by Carnap). Some thinkers suggest a
pluralist approach to the definition of information, similar to the definition of energy in physics, which refers
to potential, kinetic, electric, chemical, and nuclear types of energy. The classical approach to information,
which is a point of departure for our analysis, refers it to both theory of knowledge (epistemology) and theory
of being (ontology and metaphysics). See P. Adriaans (2012) Information, in The Stanford Encyclopedia of
Philosophy, red. Edward N. Zalta, Fall 2013, https://plato.stanford.edu/archives/fall2013/entries/information/.

12
organisms of S1, when joined, is not disposed to the “old” substantial form of the species S1, but to a
“new” substantial form of a new species S2, educed from its potentiality (see fig. 1).
25
Figure 1. Hylomorphic metaphysics of an evolutionary transformation
It takes many mutations (outcomes of which are regulated by natural selection) to produce
such an effect, and its actual occurrence may be extremely difficult (if not impossible) to capture.
But this does not exclude the possibility of its occurring, especially in a situation where some
members of a species migrate to a new environment and can be modified gradually in subsequent
generations, to the point where they can no longer mate with the other descendants of their
ancestors. Thus, it becomes clear that, even if Aristotle’s biological research was far from
discovering the possibility of the transformation of species, his metaphysics left much room for
such a possibility.
26
25
Gametes, parental egg and sperm, are separate entities and should be treated as instrumental causes, so
that, normally, when united, their primary matter is disposed to the original substantial form of the type S1.
In case of an evolutionary transition, however, accidental changes in the DNA of the parental organisms that
produced given egg and sperm may dispose their primary matter in such a way that, when united, a new
substantial form of the type S2 is educed from the potency of the primary matter.
26
See Antonio Moreno, “Some Philosophical Considerations on Biological Evolution,” The Thomist 37, no. 3
(1973), 429-31; Fran O’Rourke, “Aristotle and the Metaphysics of Evolution,” The Review of Metaphysics 58
(2004), 26-27: “If Aristotle’s metaphysical analysis of growth and change is correct, the principles of form and
the affirmation of potency will hold a fortiori for the evolutionary process” (ibid., 27). In other words, even if
contemporary biology is willing to acknowledge the reality of distinct species only at given points in time
(due to constant genetic and phenotypic changes of organisms), it seems to us that the Aristotelian categories
of potency/act and primary matter/substantial form provide a sufficient ground for accommodating both
essentialist and processual aspects of living beings. On the defense of essentialism in biology see Michael
Devitt, “Resurrecting Biological Essentialism,” Philosophy of Science 75, no. 3 (2008): 344–82; Olivier Rieppel,
SF = substantial form
PM = primary matter
S1 S2 = species 1 and 2

13
V. The Importance of Esse and its Influence on Aquinas’s Definition of Creation
After he became familiar with and adopted Aristotle’s hylomorphism, Thomas Aquinas
made an original metaphysical discovery that proved crucial for his entire system of philosophy and
theology. He realized that primary matter and substantial form, defining the essence (essentia) or
nature of any contingent entity are not identical with its act of existence (esse). Thus, he introduced
one more ontological composition characteristic of each contingent being – the one of essence and
existence. He also regarded esse as the most perfect among all principles:
Being properly signifies: something-existing-in-act (ST I, q. 5, a. 1, ad 1). [It] means that-which-has-
existence-in-act (In Meta. XII, lect. 1 (§ 2419]). [Hence,] being … is the actuality of all acts, and
therefore the perfection of all perfections (Q. de pot. q. 7, a. 2, ad 9). [It is] innermost in each thing
and most fundamentally inherent in all things since it is formal in respect of everything found in a
thing (ST I, q. 8, a. 1, co.). [Taken simply,] as including all perfection of being, [esse] surpasses life
and all that follows it (ST I-II, q. 2, a. 5, ad 2).
Moreover, shifting his reflection toward a theological analysis of the perfection of esse
Aquinas attributes its primary source to the Creator who is the only being in whom esse is identical
with his essence (essentia). He thus claims all creatures have their own esse by participation in
God’s esse:
[B]eing itself belongs to the first agent according to His proper nature, for God’s being is His
substance (SCG II, 52, no. 8). In Him essence does not differ from existence (ST I, q. 3, a. 4, co.). Since
therefore God is subsisting being itself, nothing of the perfection of being can be wanting to Him (ST
I, q. 44, a. 1, co.) [Esse] belongs to all other things from the first agent by a certain participation (ST
I, q. 4, a. 2, co.). God alone is actual being through His own essence, while other beings are actual
beings through participation, since in God alone is actual being identical with His essence (SCG III,
66, no. 7).
27
His strong emphasis on the importance of esse and its ultimate origin in the divine being of
God leads Aquinas to define creatio ex nihilo not as any kind of motion or change but bringing into
existence (into being) something that has not existed before:
[W]hat is created, is not made by movement, or by change (ST I, 45, 3, co.). Creation is not change
(ST I, q. 45, a. 2, ad 2). [B]eing is the most common first effect and more intimate than all other
effects: wherefore it is an effect which it belongs to God alone to produce by his own power (Q. de
“New Essentialism in Biology,” Philosophy of Science 77, no. 5 (2010): 662–73; Travis Dumsday, “Is There Still
Hope”; and Christopher J. Austin, “Aristotelian Essentialism: Essence in the Age of Evolution,” Synthese 194,
no. 7 (2017): 2539–56.
27
See also ST I, q. 4, a. 3, ad 4; q. 104, a. 1, co.; In I Sent. d. 37, q. 1, a. 1, co.; Q. de ver. q. 5, a. 8, ad 9; SCG III, 65,
no. 3; Super de causis, 24. On the meaning of ipsum esse subsistens see Rudi A. te Velde, Participation, 119-25.
On the way Aquinas introduces the concept of esse in his writings see John F. Wippel, The Metaphysical
Thought of Thomas Aquinas: From Finite Being to Uncreated Being (Washington D.C.: Catholic University of
America Press, 2000), 238-53.

14
pot. q. 3, a. 7, co.). [I]t must be that all things which are diversified by the diverse participation of
being, so as to be more or less perfect, are caused by one First Being, Who possesses being most
perfectly (ST I, q. 44, a. 1, co.). [T]he proper effect of God creating is what is presupposed to all other
effects, and that is absolute being (ST I, q. 45, a. 5, co.).
Consequently, thinking of what more contemporary theologians distinguish as creatio continua, we
may refer it to Aquinas’s emphasis on a continual dependency of creatures on God in their being:
28
[C]reation in the creature is only a certain relation to the Creator as to the principle of its being (ST
I, q. 45, a. 3, co.) [T]he being of every creature depends on God, so that not for a moment could it
subsist, but would fall into nothingness were it not kept in being by the operation of the Divine power
(ST I, q. 104, a. 1, co.).
29
An important clarification needs to be added at this point, which will prove crucial for our
model of divine and natural causality in evolution. Even though Aquinas clearly states that esse has
its ultimate source and can only be “produced” by God, he admits that creatures can be causes of
coming into existence of other created entities. As such, they may be called causes but not of
existence (esse) as such, (i.e., causa essendi) but of coming into existence, (i.e., causa fiendi).
30
In
other words, they may be called secondary causes of coming into existence (acting under the
primary causation of God), but only instrumental causes of existence as such. For even if all actions
of efficient causality involve a bestowal of existence (being), whether substantially or accidentally,
no creature can be a source of existence for another creature. It “gives” something that is beyond
28
It is important to remember that the act of Creator sustaining being of his creatures in time can—and for
Aquinas must—be still eternal (timeless). In other words, one does not have to reject Aquinas’s concept of
divine eternity as timeless to defend the idea of creatio continua.
29
On the unity of creatio ex nihilo and creatio continua see Rudi A. te Velde, Aquinas on God: The “Divine
Science” of the Summa Theologiae (Aldershot, Hants, U.K.: Ashgate, 2006), 125.
30
See In I Sent. d. 7, q. 1, a. 1, ad 3; Q. de ver. q. 5, a. 8, ad 8; Q. de pot. q. 5, a. 1; ST I, q. 104, a. 1. It is worth
noticing that in his In Sent. Thomas might be considering the plausibility of the emanationist view of creation
in which intermediate spiritual creatures are instruments of the creation of lower creatures as such. Since he
gave up this idea in his later works, the same claim that created entities can be instrumental causes of coming
into existence (becoming) but not of existence as such (being) should be understood as an emphasis on the
fact that creatures cannot, sensu stricto, create anything. Only the cause of existence (esse) as such can be
called the creator and this is God. Creatures are merely instruments of coming into existence of other
creatures. Note that this view is not occasionalist as the action of creatures is not only apparent, while
everything is, in fact, caused by God. For Aquinas causation of secondary and instrumental causes is real and
autonomous within the immanent order of causation, while it always depends on the primary and principal
causation of God.
The phrase “as such”—introduced here and used repeatedly in the remaining sections of the article in
reference to the metaphysical categories of existence and essence (including primary matter and substantial
form)—is thought as a way of describing them in a more static aspect of what they are. It is contrasted with
the complementary dynamic side of the same metaphysical categories, expressed in terms such as “coming
into existence (into being),” “informing (actualizing) primary matter,” “educing (eduction of) substantial form
from the potentiality of primary matter.”

15
its own capacities to offer, or rather provides some suitable circumstances in which God bestows
esse on a new contingent entity. Hence, contingent entities must be classified as instrumental
causes of being as such (esse), dependent on the principal agency of God, the only source of being:
[N]o lower agents give being except in so far as they act by divine power. Indeed, a thing does not
give being except in so far as it is an actual being. But God preserves things in being by His
providence... Therefore, it is as a result of divine power that a thing gives being (SCG III, 66, no. 1-
2).
31
There is one more important thing we should mention. Following Aquinas in his emphasis
on the importance of esse, we must not forget that creation for him is not limited to the fact of the
dependency of contingent entities on God in existence but also entails their dependency on the
Creator in their essence. In fact, on several occasions Aquinas emphasizes that all four Aristotelian
types of causation, and even the per accidens (i.e., quasi-causal) character of chance—all of them
being crucial for explaining the way things are, remain stable and change into one another—have
their ultimate origin and source in God. This fact can be explained as follows:
1. Material cause. Although it would be erroneous to assert that God (total actuality) is the
ultimate primary matter (total potentiality) of each being, primary matter does come from
God and retains a likeness to him: “also primary matter is created by the universal cause of
being” (ST I, q. 44, a. 2, co.). God’s action finds its expression in creating and providing
primary matter as a source and principle of potentiality, and of all changes in nature.
2. Formal cause. Because formal cause reduces primary matter from potentiality to act, we
may appropriately consider God as the ultimate source of formal causation. Hence, states
Thomas, “Form is something divine and very good and desirable.” The reason we can say it
is divine is because “every form is a certain participation in the likeness of the divine being,
which is pure act. For each thing, insofar as it is in act, has form” (In Phys. I, lect. 15 [§ 135]).
In other words, through their substantial form, creatures possess, in part, the actuality that
31
See also SCG III, 67, no. 1; SCG II, 21; Q. de pot. q. 3, a. 7, co.; ad 3; ad 16; Q. de pot. q. 5, a. 1, co.; ST I, q. 45,
a. 5, co.; q. 104, a. 1, co. Wippel notes that “[F]or Thomas, whenever a new substance is efficiently caused by
a natural or created agent, that agent’s causation applies both to the act of being itself (esse) of the new
substance and to a particular determination of esse as realized in that substance. Causation of the particular
determination (this or that kind of form) is owing to the created efficient cause insofar as it operates by its
own inherent power as a principal cause. Causation of the act of being itself (esse) is assigned to it as an
instrumental cause acting with the power of God and to God himself as the principal cause of the same. From
this it follows that one should not maintain that Thomas denies that created causes can efficiently cause the
act of existing or the act of being, at least in the process of bringing new substances into being” (Wippel, The
Metaphysical, 213).

16
is infinite in the Creator. Consequently, God can be said to act in the world as the Creator
of all forms and the source of all actuality.
32
3. Efficient cause. Aquinas sees God as the first source of all efficient causation. He states,
“all agents act in virtue of God himself: and therefore He is the cause of action in every
creature” (ST I, q. 105, a. 5, co.). He thinks that the likeness between the agent, i.e., the
efficient cause, and its effects observed in nature, makes it unreasonable to pass over the
natural generators of substantial forms and to claim that God obviates the causality of
natural agents. It is this way of thinking that makes him suggest distinctions between
primary and secondary and between principal and instrumental causation of God and his
creatures—distinction which we have already discussed above.
4. Final cause. Similar to other modes of causation, all forms and cases of natural teleology
(which Aquinas calls after Aristotle a “cause of causes”) find their ultimate source in God.
He notes that “the end of all things is some extrinsic good,” which is “outside [extrinsic to]
the universe” (ST I, q. 103, a. 2, co.). It is desired by all creatures as they are looking for the
fulfillment of their nature. In other words, ἐντελέχεια, an ultimate actualization of form in
the final state of an entity, bears some likeness to God and his goodness. It brings Aquinas
to the conclusion that “everything is (…) called good from the divine goodness, as from the
first exemplary effective and final principle of all goodness” (ST I, q. 6, a. 4, co.).
Consequently, we may assert that “All things desire God as their end, when they desire some
good thing, whether this desire be intellectual or sensible, or natural, i.e. without
knowledge; because nothing is good and desirable except forasmuch as it participates in the
likeness to God” (ST I, q. 44, a. 4, ad 3.).
5. Chance. Thomas agrees with Aristotle that chance and fortune are not causes per se. At the
same time, as per accidens types of causality, they must be related to proper material, formal,
efficient, and final causes, relevant to entities and dynamical systems in which they occur
(see In Phys. II, lect. 7-10 [§ 198-238], especially § 218). As such, chance events are classified
as contingent events, which Aquinas sees as remaining under God’s providence: “God, Who
is the governor of the universe, intends some of His effects to be established by way of
necessity, and others contingently” (SCG III, 94, no. 11.). “Things are said to be fortuitous as
32
At this point Aquinas goes beyond the metaphysics of Aristotle and his theory of intrinsic formal causation,
introducing the Platonic idea of external exemplar forms (causes), which he sees not as subsisting entities,
but as ideas in the mind of God: “[I]n the divine mind there are exemplar forms of all creatures, which are
called ideas, as there are forms of artifacts in the mind of an artisan” (Quod. 8, 2).

17
regards some particular cause from the order of which they escape. But as to the order of
Divine providence, ‘nothing in the world happens by chance,’ as Augustine declares” (ST I,
q. 103, a. 7, ad 2.).
All four causes (material, formal, efficient, and final), as well as the quasi-causality of chance
occurences, are crucial for the eduction of a given substantial form from the potentiality of primary
matter in each substantial change. They may be thus classified as causes of the essence of a new
entity that comes into being. In analogy to the perfection of esse, we must say that God as Creator
of primary matter and all forms, source of efficient causality and natural teleology, as well as the
transcendent cause of the occurences attributed to chance and fortune, is the first and ultimate
cause of the essence (essentia) of each contingent entity. At the same time, created agents can be
regarded both as secondary causes of essences of other contingent beings, i.e., secondary causes of
the eduction of a given substantial form from the potentiality of primary matter (also through
properly disposing it to go through a suitable substantial change), as well as instrumental causes of
the essence (essentia) as such of a given being (dependent on the principal causality of God).
Consequently, to be created means for Aquinas to be dependent on God in esse and in
essentia (in existence and in essence). This rule applies both to entities that came into being ex
nihilo at the beginning of creation and existed or still exist in time, as well as to those that come
into being throughout the history of the universe from already existing matter, due to causality of
other creatures. The latter can be classified as secondary causes of the essence (essentia) of a given
entity (through the eduction of a proper substantial form from the potentiality of primary matter)
and instrumental causes of the essence as such, as well as secondary causes of coming into existence
(esse) of the entity in question and instrumental causes of its existence as such.
33
VI. On the Possibility of Creation Through Biological Evolution
Our description of the meaning of creation within the framework of the Aristotelian-
Thomistic system of philosophy and theology enables us to suggest an answer to the question
concerning the possibility of creation through the processes of biological evolution, understood in
terms of the universal common descent.
34
While the vast majority of contemporary Thomists claim
33
The origin of each new human being is an exception here. Aquinas believes God creates an immortal soul
ex nihilo when a new human person begins to exist.
34
Although a similar answer might be given with respect to chemical and biochemical evolution, our concern
here is evolution in the realm of animate matter.

18
that this version of theistic evolution is consistent with their master’s teaching,
35
Michael
Chaberek—a supporter of the theory of intelligent design—finds it rather at odds with some
fundamental elements of Aquinas’s system of thought and claims that the only evolutionary model
that can be accepted is a version of progressive creation, i.e., a diversification of species from
ancestral, divinely produced, “natural species.”
36
An attempt at answering the question regarding which of these two versions of evolutionary
theory might be acceptable within the framework of the Thomistic philosophy and theology—when
based on the selection of some crucial passages from the works of Aquinas concerning creation and
species—does not seem to effect in a clear-cut solution to the problem (see tab. 1). Hence, what we
aim to offer hereafter is a new interpretation of the classical Thomistic notion of creation—based
on ST I, qq. 44-49, ST I, qq. 65-74, and parallel texts in other works of Aquinas—in reference to
some most fundamental principles of his own metaphysics (remembering its roots in the thought
of Aristotle). We believe that such interpretation will enable us to argue in favor of the plausibility
of the theory of evolution, understood in terms of the universal common descent, within the
Thomistic system of thought. We think it is possible despite the common and, in a way, simplistic
opinion that Aquinas himself considered creatures to be capable only of acting as instrumental
causes of new members of their own species or kind and held that the first members of each kind
were produced by God without ancestors.
35
Apart from the already mentioned works by Austriaco et al, Carroll, Donceel, Luyten, Maritain, Mc Mullin,
Moreno, Nogar, and O’Rourke, see Michael J. Dodds, Unlocking Divine Action: Contemporary Science and
Thomas Aquinas (Washington D.C.: Catholic University of America Press, 2012); Ryan Fáinche, “Aquinas and
Darwin,” in Darwin and Catholicism: The Past and Present Dynamics of a Cultural Encounter, ed. Louis
Caruana (London ; New York: T&T Clark, 2009), 43–59; Étienne Gilson, From Aristotle to Darwin and Back
Again: A Journey in Final Causality, Species, and Evolution (Notre Dame, IN: Notre Dame Press, 1984); George
P. Klubertanz, “Causality and Evolution,” Modern Schoolman 19 (1941): 11–14; Gerard M. Verschuuren, Aquinas
and Modern Science: A New Synthesis of Faith and Reason (Kettering, OH: Angelico Press, 2016).
36
The main argument by Chaberek can be found in his Aquinas and Evolution (Lexington: The Chartwell
Press, 2017). It is similar to the position proposed by the Jesuit Erich Wasmann in 1906 (English translation:
Modern Biology and the Theory of Evolution [London: Kegan Paul, Trench, Trübner & Company, 1910]). James
Hofmann, in his forthcoming article on the legacy of the concept of “natural species” in the Catholic debate
on evolution mentions and analyzes other thinkers using this term in their argumentation such as: Hermann
Muckermann, Joseph Gredt, Richard P. Phillips, Mortimer Adler, and Anthony C. Cotter. It is known that in
the second edition of The Origin (page 481, Peckham ed. 1959, page 748) Darwin referred with an approval to
the letter of Charles Kingsley, who – accepting the idea of what we might call “natural species” – claimed: “I
have gradually learnt to see that that it is just as noble a conception of deity to believe that he created primal
forms capable of self development (…) as to believe that he required a fresh act of intervention to supply the
lacunas which He himself had made” (Letter from Charles Kingsley, 18 November 1859,
https://www.darwinproject.ac.uk/letter/DCP-LETT-2534.xml). Hofmann claims that Chaberek’s use of the
concept of “natural species” is retrograde as it did not stand up to the criticism of the contemporary biological
science.

19
Table 1. Selection of the passages from the works of Aquinas showing the complexity of the
debate on the possibility of creation through biological evolution within his system of philosophy
and theology.
On the possibility of creation
of new species
De pot.
q. 4, a. 2, ad 22
“In its beginning the universe was perfect with regard to its species (quantum ad species).”
ST
I, q. 69, a 2, co.
“[T]he first constitution of species belongs to the work of the six days, but the reproduction
among them of like from like, to the government of the universe.”
ST
I, q. 118, a. 3, ad 2
“To the perfection of the universe there can be added something daily with regard to the
number of individuals, not, however, with regard to the number of species.”
ST
I, q. 73, a. 1, ad 3
“Nothing entirely new was afterwards made by God, but all things subsequently made had in
a sense been made before in the work of the six days. (…) Species, also, that are new, if any
such appear, existed beforehand in various active powers; so that animals, and perhaps even
new species of animals, are produced by putrefaction by the power which the stars and
elements received at the beginning. Again, animals of new kinds arise occasionally from the
connection of individuals belonging to different species, as the mule is the offspring of an ass
and a mare; but even these existed previously in their causes, in the works of the six days.
Some also existed beforehand by way of similitude, as the souls now created.”
In I Sent.
d. 44, q. 1, a. 2, co.
“[T]he universe can be made better, either through the addition of many parts, that is to say,
so that many other species would be created, and that many degrees of goodness that can exist
would be complete, since the distance between the highest creature and God is still infinite;
and thus God could have made [in this way] the universe better and can still do it.”
On the possibility of creation
through biological evolution
(transformism)
ST
I, q. 45, a. 5, co.
“[I]t is impossible for any creature to create, either by its own power or instrumentally—that
is, ministerially.”
ST
I, q. 65, a. 3, co.
“[N]o secondary cause can produce anything, unless there is presupposed in the thing
produced something that is caused by a higher cause. But creation is the production of a thing
in its entire substance, nothing being presupposed either uncreated or created. Hence it
remains that nothing can create except God alone, Who is the first cause. Therefore, in order
to show that all bodies were created immediately by God, Moses said: ‘In the beginning God
created heaven and earth’.”
ST
I, q. 65, a. 4, co.
“[I]n the first production of corporeal creatures no transmutation from potentiality to act can
have taken place, and accordingly, the corporeal forms that bodies had when first produced
came immediately from God, whose bidding alone matter obeys, as its own proper cause.”37
37
Aquinas’s notion of an immediate derivation of “corporeal forms” of first exemplars of animate creatures
effected by God raises the question of whether what he meant was a direct intervention of God in the origin
of each new species. An answer to this question is rather complex. Commenting on the second book of
Sentences of Lombard (d. 14, q. 1, a. 5, ad 6) Aquinas claims that the origin of plants requires merely causal
principles proper for the work of distinction (opus distinctionis – we will say more about it below), and adds
that the role of the father in this process belongs to the powers of celestial bodies, while the role of the mother
is fulfilled by the primordial matter (elements – see below). Similar is his opinion presented in De Pot. q. 3,
a.2, ad 28: “Now the production of plants from the earth into actual existence belongs to the work of
propagation, since the powers of the heavenly body as father, and of the earth as mother suffice for their
production. Hence the plants were not actually produced on the third day but only in their causes: and after
the six days they were brought into actual existence in their respective species and natures by the work of
government.” The case of animals might look different. Concerning their origin Aquinas emphasizes that
“[T]hose things that are naturally generated from seed cannot be generated naturally in any other way. (...)
[I]n the natural generation of all animals that are generated from seed, the active principle lies in the

20
SCG
III, 66, no. 4, 6
“[B]eing is the proper product of the primary agent, that is, of God; and all things that give
being do so because they act by God’s power. … [S]econdary agents, which are like
particularizers and determinants of the primary agent’s action, produce as their proper effects
other perfections which determine being.”
In II Sent.
d. 12, q. 1, a. 2, co.
“[W]ith respect to the beginning of the world something pertains to the substance of faith,
namely that the world began to be by creation, and all the saints agree in this. But how and in
what order this was done pertains to faith only incidentally insofar as it is treated in scripture,
the truth of which the saints save in the different explanations they offer.”
De pot.
q. 5, a. 1, co.
“[T]his incorporeal agent by whom all things, both corporeal and incorporeal are created, is
God, as we have proved above (De pot., q. 3, aa. 5, 6, 8), from whom things derive not only
their form but also their matter. And as to the question at issue it makes no difference whether
they were all made by him immediately, or in a certain order as certain philosophers have
maintained.”38
De pot.
q. 3, a. 10, ad 2
“The universe in its beginning was perfect (…) as regards nature’s causes from which
afterwards other things could be propagated, but not as regards all their effects.”
De pot.
q. 4, a. 2, co.
“[W]hen he [God] made things out of nothing he did not at once bring them from nothingness
to their ultimate natural perfection, but conferred on them at first an imperfect being, and
formative power of the seed. (...) The material principle, however, in the generation of either kind of animals,
is either some element, or something compounded of the elements. But at the first beginning of the world
the active principle was the Word of God, which produced animals from material elements, either in act, as
some holy writers say, or virtually, as Augustine teaches” (ST I, q. 71, ad 1; see also In II Sent. dist. 14, a. 5, ad
6). This theological opinion of Aquinas leaves space for an interpretation assuming a direct divine
intervention in the production of each animal species (see also the passage from In II Sent.
d. 1, q. 1, a. 4, co. in the second section of the table, which seems to argue even stronger in favor of the necessity
of such an intervention). At the same time, however, it is possible to think that, similar to the case of plants,
the “virtual” presence of animals as rationes seminales in the primitive matter required merely the “regular”
work of government for them to become actualized. Divine intervention in their origin would then refer –
again, similar to the case of plants – merely to the instantiation of their proper rationes seminales.
Note that when Thomas emphasizes that “the corporeal forms that bodies had when first produced came
immediately from God” (ST I, q. 65, a. 4, co.), he speaks about immediate origin of forms from God in
opposition to Plato and Avicenna who thought corporeal forms were derived from spiritual substances (see
our comment in note 30). At the same time, we need to remember that Aquinas does speak about causal
influence of spiritual (separated) substances (angels) in creation: “Corporeal forms, therefore, are caused, not
as emanations from some immaterial form, but by matter being brought from potentiality into act by some
composite agent. But since the composite agent, which is a body, is moved by a created spiritual substance,
as Augustine says (De Trin. III, 4,5), it follows further that even corporeal forms are derived from spiritual
substances, not emanating from them, but as the term of their movement” (ST I, q. 65, a. 4, co.). Moreover,
in reference to Aristotle’s cosmology, he also speaks about the influence of the celestial bodies (sun and stars)
on the events taking place on earth: “The heavenly bodies inform earthly ones by movement, not by
emanation” (ST I, q. 65, a. 4, ad 3). See also SCG III, 67, no. 5; SCG III, 69, no. 24; ST I, q. 118, a. 1, ad 3; Q. de
pot. q. 3, a. 8, ad 15. Both of these claims are intriguing and defendable philosophically and theologically.
However, we must remember that separated substances and celestial bodies are not mediators of divine
action, but participants entering a complex nexus of secondary and instrumental causes engaged in
substantial transformations taking place in the universe.
38
“The first explanation of these things namely that held by Augustine [things were made in a certain order]
is the more subtle, and is a better defense of Scripture against the ridicule of unbelievers: but the second
[things were made immediately] which is maintained by the other saints is easier to grasp, and more in
keeping with the surface meaning of the text. Seeing however that neither is in contradiction with the truth
of faith, and that the context admits of either interpretation, in order that neither may be unduly favored we
now proceed to deal with the arguments on either side” (De pot. q. 4, a. 2, co.).

21
afterwards perfected them, so that the world was brought gradually from nothingness to its
ultimate perfection.”
De pot.
q. 5, a. 5, ad 13
“God in bringing all creatures into being out of nothing, himself instituted the first perfection
of the universe, consisting in the principal parts thereof, and the various species of things: and
that in order to give it its final perfection, consisting in the completion of the ranks of the
blessed, he ordained the various movements and operations of creatures, some of which are
natural, for instance, the movement of the heavens and the activities of the elements, whereby
matter is prepared to receive rational souls, while others are voluntary such as the
ministrations of the angels who are sent to minister for them who shall receive the inheritance
of salvation.”
In II Sent.
d. 1, q. 1, a. 4, co.
“[Some things come into being neither through motion nor through generation] because of
the necessity that generation always generates what is similar in species. For this reason the
first members of the species were immediately created by God, such as the first man, the first
lion, and so forth. Man, for instance, can only be generated from man. It is, however,
otherwise with those things which are not generated by an agent that is similar to them in
species. For these, rather, the power of celestial bodies along with appropriate matter is
sufficient, as, for example, those things which are generated by putrefaction.”39
What is crucial, in our opinion, is the fact that creation ex nihilo in Aquinas’s treatise on the
work of the six days refers first and foremost to the act of coming into being out of nothing (i.e.,
not from a preceding being of any kind) of the most primitive types of contingent entities, i.e., the
elements. Distinguishing the work of creation (opus creationis) from those of distinction (opus
distinctionis) and adornment (opus ornatus), Aquinas notes that it is, in fact, inseparable from the
first three stages of distinction, the second of which is the distinction “of the elements according to
their forms.” And even if only earth and water are named, adds Thomas, the author of Genesis 1:2
had in mind air and fire as well. The reason he does not mention them is that “the corporeal nature
of these would not be so evident as that of earth and water, to the ignorant people” to whom he
spoke. (ST I, q. 66, a. 1, ad 2 sed cont.).
It seems that for Aquinas the subsequent creation of more complex contingent beings is in
a way mediated through those most basic forms of material stuff. Not in a sense that these primitive
entities would have the power to create – they cannot possess the power which belongs only to
39
Steven Baldner and William Carroll offer a commentary to this passage in their translation of Aquinas’s
work: “Aquinas, following the ancients, thought that worms, for instance, could be generated from the rotting
of garbage. The garbage had to have the appropriate matter (the right active and passive qualities) and the
action of a celestial body (the sun) was required. The biology here is incorrect, of course, but the philosophical
point is what is important. Aquinas is saying that animal and plant generation need not, in principle, always
take place from parent members of the species. That such, in principle, could happen is needed for a doctrine
of evolution. Aquinas, of course, did not hold a doctrine of evolution, but the point that he is making here is
important if his philosophy is to be held to be compatible with a doctrine of evolution” (Saint Thomas
Aquinas, Aquinas on Creation: Writings on the “Sentences” of Peter Lombard, Book 2, Distinction 1, Question
1, trans. Steven E. Baldner and William E. Carroll [Toronto: Pontifical Institute of Mediaeval Studies, 1997],
85, footnote 51.

22
God. And yet, more complex entities, in some respect, came “from” them. For it was the earth, reads
Aquinas, that brought forth plants: the green herbs and fruit trees. It was water that brought forth
an abundance of swimming creatures and birds (although Genesis does not say explicitly where
they came from). It was earth that brought forth all kinds of living creatures: cattle, creeping things,
and wild animals of all kinds. Although it is not quite clear whether he wholly embraced Augustine’s
theory of rationes seminales (seminal notions), Aquinas refers to his suggestion that plants and
trees might have been produced “in their origin or causes,” i.e., the earth “received … the power to
produce them.” They were subsequently brought into existence in “the work of propagation” (ST I,
q. 69, a. 2, co.). Similarly with fishes and birds, which Augustine saw as produced by “the nature of
waters on that [fifth] day potentially” (ST I, q. 71, co.), and animals, whose “production was
potential” as well (ST I, q. 72, co.).
One might rightly say that Augustine thought all species were, in fact, already present in
the work of the six days, but their presence in potency (rationes seminales) might be referred—
within the system of Aristotelian-Thomistic metaphysics—to the potentiality of primary matter
from which—provided it is properly disposed—any type of substantial form can be educed. Hence,
what Aquinas qualifies as the work of propagation, might be seen as a gradual transformation
disposing primary matter to be informed by particular types of substantial forms, typical of different
and new kinds of species. The radical change comes with the origin of man, whose life, “as being
the most perfect grade, is not said to be produced, like the life of other animals, by earth or water,
but immediately by God” (ST I, q. 72, ad 1). What is meant here is that each human soul is directly
created by God.
It is important to acknowledge that Aquinas does not seem to speak about the creation of
more complex inanimate and animate species ex nihilo. He does say that “the corporeal forms that
bodies had when first produced came immediately from God,” to which he adds “whose bidding
alone matter obeys, as its own proper cause” (ST I, q. 65, a. 4, co.). This crucial passage is difficult
to interpret. It needs to be read in reference to the fundamental difference Aquinas sees between
generation and creation:
[Creation] presupposes nothing in the thing which is said to be created. In this way it differs from
other changes, because a generation presupposes matter, which is not generated, but rather which is
transformed and brought to completion through generation. In other changes a subject which is a
complete being is presupposed. Hence, the causality of the generator or of the alterer does not extend
to everything which is found in the thing, but only to the form, which is brought from potency into
actuality. The causality of the Creator, however, extends to everything that is in the thing. And,
therefore, creation is said to be out of nothing, because nothing uncreated pre-exists creation” (In II
Sent., 1, 1, 2, co.).

23
The problem is that although we speculatively distinguish between generation (which refers
to the origin of an entity) and creation ex nihilo (which refers to its entire duration and existence),
in reality we deal with entities that are both generated and, at least indirectly, created ex nihilo. In
order to explain this metaphysical puzzle, we may say that all creatures are created ex nihilo in
terms of their existence (esse), which is bestowed on them at any moment of their duration in time
by God (whose action can be thus called conservatio a nihilo), as well as in their essence (essentia),
since all substantial forms and primary matter as such come immediately from God. At the same
time, concerning their coming into existence (being) and the act of the eduction of their substantial
form from the potentiality of primary matter, they are generated in natural and contingent
processes which engage many causal factors classified as secondary and instrumental causes. In
other words, we might say that all contingent entities that come to be after the initial creation of
the basic elements are created ex nihilo by the primary causal agency of God with reference to their
esse and essentia taken as such. At the same time, they are generated by the secondary and
instrumental agency of other creatures with reference to the change which effects their coming into
existence (being) and the eduction of their substantial form from the potentiality of primary
matter.
40
With all this in mind, we can suggest an extension of Aquinas’s doctrine of creation to
include the theory of biological evolution, while obeying the principles of his system of thought.
We might say that in the lineage of subsequent generations of organisms belonging to a given
species S1 a substantial change might occur which effects an actualization of properly disposed
primary matter by a new substantial form belonging to the new species S2. Paraphrasing Aquinas’s
assertion from ST I, q. 65, a. 4, co. we might say that the corporeal form (as such) that the first
exemplar of the species S2 has when first produced comes immediately from God, while its eduction
from the potentiality of primary matter effects from the secondary and instrumental causality of
other creatures. The creatures in question act under the primary and principal causality of God,
whose bidding alone (primary) matter obeys, as its own proper cause. Understood this way, an
40
This explanation becomes a practical application of the speculative philosophical and theological concept
of creatio ex nihilo—defined in earlier parts of our analysis—in an interpretation of the creation story in
Genesis. Following the first book of the Bible, it assumes the beginning of creation in time (or the beginning
of time with creation). We must not forget, however, that in his philosophical analysis Aquinas assumed that
the world might have been everlasting (i.e., existing in time but with no beginning in time). In ST I, q. 46, a.
2, co. we find him saying: “By faith alone do we hold, and by no demonstration can it be proved, that the
world did not always exist.” But even if the world is everlasting, it does not contradict the truth of its status
of being created ex nihilo.

24
evolutionary change is neither simply generation, nor a direct creation ex nihilo (which in Aquinas’s
interpretation of the work of six days seems to refer to the most basic elements). It is a change—
similar to the majority of substantial changes in the realm of inanimate and animate nature—that
brings together those two aspects of contingent entities (i.e., being generated and created ex nihilo).
Naturally, an important question remains regarding a more thorough and exact causal
description of this process (including the distinction between secondary and instrumental causes
and specifying the nature of their action in an evolutionary transition) and a concern that it may
be at risk of violating the key rule of Aquinas’s creation theology which ascribes the power to create
only to God. We hope that our model of the divine and creaturely action in evolutionary transitions
presented below will help to clarify these issues.
VII. Concurrence of Divine and Natural Causes in Begetting Offspring
Having in mind all abovementioned principles of Aristotelian philosophy and Aquinas’s
definition of creation, we can now present our model of divine and natural causes concurrent in
evolutionary transformation of species. We will describe it within the framework distinguishing
between the two related, yet distinct orders of causation: the immanent and the transcendent. We
will begin from a regular case of giving birth to an organism of the same species (see Fig. 2).

25
Figure 2. Concurrence of divine and natural causes in begetting offspring of the same species
In the immanent order of causation, looking at parental organisms (♀ and ♂) in the process
of generating their offspring, we perceive them simply as proper causes of such an occurrence. We
say it is due to their natural causal activity that a new exemplar of the same species comes into
being.
41
Applying principles of the metaphysics and theology of Aristotle and Aquinas, however, we
distinguish, first, between essence and existence of the newly born organism. Analyzing its essence,
we realize that the proper causal activity of the parents is not, in fact, a cause of primary matter and
the substantial form as such of their offspring. Otherwise they would be causes of themselves, since
each of them is also an exemplar of the same species in virtue of that form. The first and ultimate
cause of the essence of each contingent entity can only be God, the Creator of primary matter and
all substantial forms. Nothing prevents us, however, from attributing to parental organisms the role
of instrumental causes of the essence of their offspring. Because their causal activity is accompanied
by the instantiation of a new exemplar of their own species, it can be classified as instrumental for
their offspring’s essence taken as such. They make possible something which, strictly speaking, is
beyond their own capacities to offer, i.e., the fact of the actualization of primary matter by a right
kind of substantial form of a given species (the principal cause of primary matter and substantial
form is God).
42
Moreover, the same parental organisms can be categorized as secondary causes of
the eduction of the proper substantial form from the potentiality of primary matter, in the process
of begetting their offspring, i.e., secondary causes of the process of instantiation of a particular
41
Proper cause (causa propria) can be understood as an individual or particular cause, as distinguished from
a general or universal cause. Aquinas uses the term causa propria in ST I, q. 2, a. 2, co. As such, it seems to
belong to the most preliminary and intuitive causal description of the stability and change of things in nature.
42
“[A]ll forms are potentially in prime matter, but they are not actually there, as those who held the
‘hiddenness’ doctrine said. The natural agent produces not the form but the composite, by bringing form
from potentiality to actuality. This natural agent by its own action is, as it were, an instrument of God Himself
who, as agent, both makes the matter and gives it the potency for form” (In II Sent., d. 1, q. 1, a. 4, ad 4).
SF = substantial form
PM = primary matter
S1 = species 1
Principal causation of God working through instrumental causation of creatures
Primary causation of God working through secondary causation of creatures

26
exemplar of the substantial form of their own species in a given “portion” of a signate mater, which
is a principle of individuation.
43
As such, they give what is within their natural dispositions to offer,
while being dependent in their action on the primary causality of God, the source of all efficient
action leading to the actualization of primary matter by various types of substantial forms and the
ultimate end of natural teleology in all creatures.
44
As for the existence (esse) of a new organism, conceived by its parents, its first and principal
cause can only be God. This fact concerns not only the existence of each contingent being in the
ontological meaning of this term (existence as such), but also each contingent entity’s coming into
being (existence) and its further persistence in time (keeping in existence). God is the first and
principal cause of creaturely esse in all three of these aspects. This is because esse has only one
source, which is God, who always bestows it on his creatures (or rather allows them to participate
in his own esse).
At the same time, it seems right to say that the operation of efficient causes (parental
organisms acting in the immanent order of causation) is accompanied or followed by coming into
being of their offspring, even though they are not first and principal causes (sources) of esse as such.
Therefore, they can be described as secondary causes of coming into existence of their offspring,
acting with the power given them by God – the transcendent and first source of all esse in the
immanent order of created world. Note that we are talking here about secondary causation, since
the causality of parental organisms which is followed by an instantiation (coming into being) of the
esse of a new exemplar of their own species lies within their natural dispositions. Similarly,
sustaining contingent entity in being (esse) is also the work of God as the primary cause. At the
same time, it seems right to say God does that using secondary causes that work in the immanent
43
“Nature or quiddity [in substances composed of matter and form] is received in designated matter (materia
signata). ... And because of the division of designated matter, the multiplication of individuals in one species
is here possible” (De ente IV, 98). “Hence the form of the thing generated depends naturally on the generator
in so far as it is educed from the potentiality of matter, but not as to its absolute existence” (De pot. q. 5, a. 1,
co.).
44
“Now it is clear that of two things in the same species one cannot directly cause the other’s form as such,
since it would then be the cause of its own form, which is essentially the same as the form of the other; but it
can be the cause of this form for as much as it is in matter—in other words, it may be the cause that this
matter receives this form. And this is to be the cause of becoming, as when man begets man, and fire causes
fire. Thus whenever a natural effect is such that it has an aptitude to receive from its active cause an
impression specifically the same as in that active cause, then the becoming of the effect, but not its being,
depends on the agent” (ST I, q. 104, a. 1, co.). See also SCG II, 21, no. 8; III, 65, no. 4; ST I, q. 13, a. 5, ad 1.

27
order of causation.
45
Hence, to give an example, parents of a newborn offspring taking care of its
wellbeing should be considered as secondary causes of sustaining it in existence (esse). They realize
their natural dispositions, while acting by the power of God, who is the first cause of creatio
continua. Moreover, even if esse as such has God as its principal cause, contingent creatures can be
considered as causing it instrumentally. They cannot “give” esse, but their agency brings or is
accompanied by an instantiation of a new organism, which has esse bestowed on it by God.
Consequently, we can say that parental organisms giving birth to a new exemplar of their
own species are: (1) proper causes of its coming into being (in a most basic and pre-philosophical
causal explanation); (2) secondary causes of the instantiation of its essence (i.e., the eduction of the
appropriate form from the potentiality of primary matter), and of its coming into existence and
keeping in existence (permanence in time) – dependent on the primary causality of God, the origin
and source of all efficient causality effecting the actualization of primary matter by the variety of
substantial forms and the ultimate end of natural teleology in creatures; and (3) instrumental causes
of the new organism’s essence (essentia) and existence (esse) as such – dependent on the principal
causation of God, the Creator of primary matter and all substantial forms, and the first and only
source of esse. Note that creaturely esse, though having its primary and direct source in God (being
de facto a participation in divine esse) is not the same as God’s esse. It is esse that does come from
God but is proportionate to the essence (essentia) of a creature and not identical with it. Hence, we
predicate esse of creatures analogously (using both analogy of attribution and of proper
proportionality).
In other words, the same action of parental organisms, which are considered as proper
causes of their own descendant within the immanent order of causation, has the nature of
secondary and instrumental causation from the point of view of the transcendent order of
causation, in which God himself is the first and principal cause of the essence and existence of every
contingent being.
The distinction between primary and principal causation of God and the secondary and
instrumental causation of creatures seems to be crucial here. It helps us avoid the two extreme
positions of deism (God who created the universe and the laws of nature is no longer actively
engaged in its existence and the changes it is going through), and occasionalism (causation of
creatures is not real but is merely an occasion for God to act). Creatures exercise causal action that
45
See ST I, q. 104 a. 2 sed contra: “God gives being by means of certain intermediate causes,” so too God “keeps
things in being by means of certain causes.”

28
is real and proper to their dispositions. Their agency, however, has the character of secondary
causation in educing forms from the potentiality of primary matter and coming into existence of
new contingent entities. Considering the essence and existence as such of these novel beings, other
creatures can only be regarded as their instrumental causes, which emphasizes the depth of the
involvement and causal activity of God as the primary and principal cause of creation.
Consequently, our analysis shows there is no opposition between the two already
mentioned texts in Thomas’ Summa Theologiae and Summa Contra Gentiles, the first stating “it is
impossible for any creature to create, either by its own power or instrumentally—that is,
ministerially” (ST I, q. 45, a. 5, co.), and the second asserting that “being is the proper product of
the primary agent, that is, of God; and all things that give being do so because they act by God’s
power” (SCG III, 66, no. 4). In order to understand that they do not contradict each other, it suffices
to realize that secondary agents (acting in the immanent causal order) can cause the eduction of a
suitable substantial form from the potentiality of primary matter and the coming into existence of
a new contingent entity (causa fiendi) but are never causes of its essentia and esse as such (causa
essendi). The principal cause of creation of essence and existence of new entities is God. Even if
other creatures can be regarded as instrumental causes of their essence and existence, they are not,
strictly speaking, causing them. Their agency is simply providing suitable conditions for the
instantiation of new entities of a given type (i.e., characterized by a particular essence and its
proportionate act of existence).
VIII. Concurrence of Divine and Natural Causes in an Evolutionary Transformation
The description of causal relationships at the immanent and the transcendent levels of
causation in begetting offspring turns our attention to a special case of such occurrence, a begetting
by parents belonging to the species S1 of the first exemplar of a new species S2 (i.e., coming to be of
a new species in an evolutionary transformation).
46
The exact moment of the eduction of substantial
form of a new species is an outcome of an extremely complex process that is extended in time and
causally polygenic.
47
It involves: spontaneous chance mutations (affecting genes, chromosomes or
46
Aristotelian and Thomistic metaphysics and ontology provide a theory of discrete species. We have already
said above in note 26 that the continuity of evolutionary changes does not necessarily disprove this theory.
It merely helps us understand how difficult, if not impossible, might be an observation of the exact moment
of an evolutionary transition from S1 to S2.
47
The idea of causal polygeny of events was introduced in analytic philosophy of biology by John Dupré, who
in turn takes it from genetics, which acknowledges that many genes typically contribute to the production of

29
entire genomes), genetic recombination, gene transfer, and genetic drift, which bring changes in
genotype and phenotype of organisms that strive to survive and produce fertile offspring (natural
teleology). Contribution of these changes to the benefit of the organism is verified by the
mechanism of natural selection. All these factors, taken as a whole, can be regarded as proper causes
(or one unified cause) of the first exemplar of a new species S2 in the immanent order of causation.
Looking at this process from the perspective of the transcendent order of causation, we can define
and make a distinction between secondary and instrumental causes of the origin of the prototype
of a new species S2 (see fig. 3).
Figure 3. Concurrence of divine and natural causes in an evolutionary transition
one trait. Following Dupré, George Molnar notes not only that events are polygenic, but also that causal
powers, conversely, are pleiotropic and flexible, and can make a contribution to many different effects. See
John Dupré, The Disorder of Things: Metaphysical Foundations of the Disunity of Science (Cambridge, Mass:
Harvard University Press, 1993), 123-24; George Molnar, Powers: A Study in Metaphysics, edited by Stephen
Mumford (New York: Oxford University Press, 2003), 195.
SF = substantial form
PM = primary matter
S1 S2 = species 1 and 2
Principal causation of God working through instrumental causation of creatures
Primary causation of God working through secondary causation of creatures

30
If the explanation presented here is correct, then—as in the case of an ordinary begetting of
an offspring belonging to the same species—our causal description of the instantiation of the first
representative of the new species S2 allows us to distinguish and name:
1. Proper cause of its origin in the immanent order of causation (in a most basic and pre-
philosophical causal explanation), i.e., its parental organisms, within the complex system of
immanent causes, involved in the polygenic causal origin of an evolutionary change leading
to the coming-to-be of the first exemplar of the species S2.
2. Secondary cause of the eduction of its proper substantial form from the potentiality of
primary matter, i.e., parental organisms, within the complex system of immanent causes,
involved in the polygenic process of instantiation of the first exemplar of the substantial
form of the new species S2 in a given “portion” of a signate mater, which is its principle of
individuation.
3. Instrumental cause of its essence (essentia) as such, i.e., agency of the parental organisms,
within the complex system of immanent causes, which is accompanied by the instantiation
of the first exemplar of the new species S2 (actualization of primary matter by a new kind of
substantial form of the species S2).
4. Secondary cause of its coming into existence (esse), i.e., the operation of efficient causes
(parental organisms acting within the evolutionary matrix of causes), which is accompanied
or followed by coming into being (esse) of their offspring that happens to be the first
exemplar of the new species S2.
5. Instrumental cause of its existence (esse) as such, i.e., the agency of parental organisms
(within the evolutionary matrix of causes), which brings or is followed by an instantiation
of the first exemplar of the new species S2, which has esse bestowed on it by God.
In other words, similar to the begetting of a new exemplar of the same species, parental
organisms of the species S1, analyzed within the polygenic causal matrix of an evolutionary
transition, can be regarded as proper causes of the prototype organism of the species S2 within the
immanent order of causation. The same causal agency has the nature of secondary and instrumental
causation from the point of view of the transcendent order of causation, in which God himself is
the first and principal cause of the essence and existence of every contingent being.
What seems to be crucial in this description is the distinction between secondary and
instrumental causes. Even if it belongs to the natural dispositions of the parental organisms of the
first exemplar of a new species S2 to be secondary causes of the eduction of the substantial form of

31
the prototype of S2 from the potentiality of the primary matter (essentia) and of its coming into
existence (esse)—their action in this process is proper to their natures—when it comes to the
essence (essentia) and existence (esse) as such of the first organism of S2, the parental organisms
can only be their instrumental causes—“giving” something they in fact themselves cannot offer.
The first (with respect to secondary causes) and the principal (with respect to instrumental causes)
agent in an instantiation of the prototype of S2 is God.
One might think this brings our description close to occasionalism, as it may seem that with
respect to the essence (essentia) and existence (esse) of the first exemplar of S2, the instrumental
causation of its parents (within the evolutionary matrix of causes) provides merely an occasion for
God to instantiate them. We must not forget, however, that the instrumental causation in
question—which we can verify both within the methodology of science and the philosophical
inquiry concerning causal dependencies in nature—is real and irreducible solely to the sort of
divine action that a merely empirical inquiry might mistake for actions of creatures. This type of
divine agency seems closest to a direct divine intervention in the natural order of created world.
Yet, it is neither miraculous nor occasionalist, since it is exercised in and through creatures, “giving”
something they, in fact, do not themselves have to offer. This shows the depth of the involvement
and the nature of the causal activity of God as the primary and principal cause of creation, and it
effectively protects our analysis and explanation from falling into the pitfall of deism.
48
The case of divine concurrence with natural causes in the evolution of man looks
considerably different, according to the model presented here. We need to remember that for
Aquinas God creates a new human soul (substantial form of a human being) ex nihilo at the moment
when a new human being begins to exist.
49
Thus, each human soul is not educed from the
potentiality of primary matter, as are substantial forms of all other natural beings. It is directly
created by God. Parental organisms (together with other agents in an evolutionary matrix of causes)
48
As we have already mentioned above (see note 37), Aquinas’s causal description of substantial changes also
includes causation of separate substances (angels) and celestial bodies (the sun and the stars). If we want to
follow his thought in all details, we should list these agents among other secondary and instrumental causes
entering a complex causal nexus, responsible for an evolutionary transition. It is important to remember, in
this context, that the ancient and medieval idea of causation of celestial bodies is not just a relic of an outdated
cosmology. It is not entirely implausible to see the energy emitted by the sun, forces of gravitation, and other
universal cosmological causal principles as contributing to educing particular forms from primary matter in
processes of substantial changes occurring in nature.
49
Note that—following the state of the biological knowledge of his time—Aquinas accepted the idea of the
succession of vegetative, plant, and human souls in the embryological development of a human being (see
SCG III, 22). Nonetheless, his belief in God’s creating ex nihilo human soul at the very moment in which a
new human person begins to exist, proves to be compatible with contemporary embryology as well.

32
properly dispose primary matter to receive it. Consequently, although they can be still regarded as
secondary causes of the coming into existence, as well as instrumental causes of the existence (esse)
as such of the first human being, when it comes to his/her essence (essentia) they can only be called
secondary causes of the proper disposition of primary matter to be actualized by a human soul,
which is not educed from the potentiality of primary matter but is directly created by God. This
refers to each subsequent begetting of a new human person. The direct divine action of God in
creation of human souls is not miraculous, however, as it belongs to the natural order of the
universe he created that human souls are not educed from the potentiality of primary matter but
created by God ex nihilo. Hence, the variation of our model of causation in evolution of man will
look as depicted in figure 4.
Figure 4. Concurrence of divine and natural causes in the evolution of man
SF = substantial form
PM = primary matter
S1 S2 = species 1 (humanoid) and 2 (human)
Primary causation of God (direct intervention)
Principal causation of God working through instrumental causation of creatures
Primary causation of God working through secondary causation of creatures

33
Note that we carefully avoid a claim which is popular among many theistic evolutionists
who say that the creation of the human body came through the processes of evolution, while the
first human soul was directly created by God. This statement is not entirely correct in the context
of the Aristotelian-Thomistic thought, which emphasizes that, metaphysically speaking, the proper
corelate of substantial form is always primary matter (and not secondary—i.e., already informed—
matter). Hence our claim that evolutionary processes properly disposed primary matter to be
informed (actualized) by the first human soul (directly created by God ex nihilo). This fact becomes
apparent in reference to an important passage from Aquinas’s commentary on Aristotle’s De anima:
We must not think, therefore, of the soul and body as though the body had its own form making it a
body, to which a soul is superadded, making it a living body; but rather that the body gets both its
being and its life from the soul. This is not to deny, however, that bodily being as such is, in its
imperfection, material with respect to life. Therefore, when life departs the body is not left specifically
the same; the eyes and flesh of a dead man, as is shown in the Metaphysics, Book VII, are only
improperly called eyes and flesh. When the soul leaves the body another substantial form takes its
place; for a passing-away always involves a concomitant coming-to-be (In De an. II, lect. 1 [§ 225-
226]).
The first scholar who proposed a proper interpretation of evolutionary theory within the
Aristotelian-Thomistic system of philosophy and theology was French Dominican Marie-Dalmace
Leroy. In his book on evolution we find him saying: “It is only after the infusion of the soul, and
because of the infusion itself, that man is constituted a living being. Before infusing the spirit, there
was nothing human, not even the body, inasmuch as human flesh cannot exist without the soul,
which is its substantial form. … Thus, the Bible—interpreted by theology—tells us that man’s body
cannot be derived from lower nature.”
50
IX. Difficulty Concerning Immanent Cause(s) of an Evolutionary Transformation
One of the key questions concerning the explanation and model presented here is related
to the complex system of immanent causes, involved in the polygenic causal origin of an
evolutionary change. Is it plausible and justified to treat them as a unified causal principle of an
evolutionary change? This question sends us to another metaphysical query concerning the
50
Marie-Dalmace Leroy, L’évolution restreinte aux espèces organiques (Paris: Delhomme et Briguet, 1891), 261,
as cited in Mariano Artigas, Thomas F. Glick, and Rafael A. Martínez, Negotiating Darwin: The Vatican
Confronts Evolution, 1877–1902 (Baltimore: JHU Press, 2006), 59.

34
classical principle of proportionate causation, which states that a higher effect cannot proceed from
a lower cause.
51
Emphasizing the polygenic character of causation at work in evolution, Benedict Ashley
says: “The new species is not a ‘greater emerging from the less’, because the amount of information
it contains in integrated form is no greater than the amount of information present in the historical
evolutionary process.”
52
Hence, whatever is present in the effect of evolutionary changes, must be
present in its “total” cause rather than in one of the particular causal factors. This assertion seems
to offer a fitting answer to the question concerning the conservation of the principle of
proportionate causation in evolution. One might question its accuracy, however, based on the claim
of the contemporary theorists of information who suggest that its amount actually rises with the
evolution of the universe (which does not affect the laws of physics, as long as the nature of
information is being understood as immaterial). On the other hand, measurement of information
in general becomes a problem, as it tends to frame it within the mechanist view of the universe.
Thus, it might be better simply to emphasize that ontological categories of “higher” and “lower” are
not equal to biological categories of “more” or “less complex,” or “more” or “less effective in
occupying an ecological niche.” At the same time, the argument saying that none of the particular
“partial” causes in an evolutionary matrix “aims” at an evolutionary change, and that an increase of
information is an outcome of a causally polygenic occurrence, seems to offer at least a partial answer
to the problem.
But the question concerning the unity of the evolutionary causal matrix remains open. Note
that in his explanation Ashley speaks of the “total” cause of an evolutionary transition, which seems
to assert a unity to an evolutionary causal nexus. Hence, if such unity is a fact, we might consider
introducing an important shift or twist to the causal scenario of evolutionary transitions presented
here. If we assume there must be a cause of the unity of the polygenic matrix of causal agents
engaged in an evolutionary transformation, we find it difficult, if not impossible, to find it in the
51
“[T]he begetter is of the same kind as the begotten” (Meta. VII, 8 [1033b 30]). “Effects must needs be
proportionate to their causes and principles” (ST I-II, q. 63, a. 3, co.). “[W]hatever perfection exists in an effect
must be found in the effective cause” (ST I, q. 4, a. 2, co.). “[T]he order of causes necessarily corresponds to
the order of effects, since effects are commensurate with their causes” (SCG II, 15, no. 4). “[N]o effect exceeds
its cause” (ST II-II, q. 32, a. 4, obj. 1). “[E]very agent produces its like” (SCG II, 21, no. 9). “[E]very agent acts
according as it is in act” (SCG II, 6, no. 4).
52
Benedict Ashley, “Causality and Evolution,” The Thomist 36, (1972), 215. See also Norbert Luyten,
“Philosophical Implications of Evolution,” New Scholasticism 25 (1951), 300-302; Leo J. Elders, “The
Philosophical and Religious Background of Charles Darwin’s Theory of Evolution,” Doctor Communis 37
(1984), 56. They both seem to agree with Ashley.

35
immanent order of causation, where the unity in question seems to be a chance occurrence. This
might suggest that God, as the ultimate source of all causality, acting from the transcendent order
of causation, brings unity to the evolutionary matrix of causes, causing thus directly the eduction
of substantial form of the first exemplar of a new species from the potentiality of primary matter.
All partial causes of this occurrence, including parental organisms, would act as secondary and
instrumental causes of this new organism. Their unity, however, would be an outcome of a direct
intervention of God in the created order of things.
This scenario might look less attractive for theologians emphasizing “autonomy” of natural
causes, as it suggests a direct interventionist divine action in creation of the form of each new
species. However, we must acknowledge that it is not entirely implausible and does not exclude
secondary and instrumental causation of creatures. One might suggest that God brings an
evolutionary change by working through the secondary causation of chance—i.e., the unity of an
evolutionary causal matrix occurring by chance—but we must not forget that chance is not a cause
per se, but only per accidens, as says Aristotle: “chance is an incidental cause. But strictly it is not
the cause – without qualification – of anything.”
53
This makes the alternative scenario with the
direct intervention of God in creation of forms of first exemplars of each new species (lower than
human) plausible.
54
Moreover, it also seems to be in line with the abovementioned assertion made
by Aquinas in his treatise on the work of six days in which he states that “the corporeal forms that
bodies had when first produced came immediately from God, whose bidding alone matter obeys,
as its own proper cause.”
55
The immediate dependence of the first exemplar of each new species on
God might be explained in terms of the direct divine intervention unifying evolutionary causal
nexus of causes engaged in its coming into being.
X. Conclusion: Theological Advantages and Consequences of the Proposed Model
The proposed model of understanding divine concurrence with natural causes in
evolutionary transitions has important theological advantages consequences. First of all, it protects
us from the fallacies of both deism and occasionalism. It does not see God as leaving the universe
entirely to its own causal operations after creating it, which would suggest that the origin of new
53
Phys. II, 5 (197a, 12-14).
54
Our formulation of such scenario is partly inspired by a conversation on philosophical aspects of evolution
during the session organized in the Spring of 2017 in Providence College, RI, USA.
55
ST I, q. 65, a. 4, co.

36
species is an autonomous mundane process with no need of God’s involvement at any stage of its
realization. Neither does it claim that God does everything, which would put into question the
causal autonomy of creatures engaged in complex causal processes of evolutionary transitions.
Moreover, although we have suggested that God works in evolution through secondary and
instrumental causation of his creatures rather than through his direct divine intervention, the latter
(instrumental) type of causation puts an emphasis on the depth of God’s involvement in
evolutionary transitions. It reminds us that when it comes to the essence (essentia) and existence
(esse) as such of the first exemplar of a new species (as well as all subsequent organisms of the same
species) God is their principal cause, as it is beyond the capacity of contingent entities to be the
source of essence and existence as such of any other created beings. What is more, God’s
involvement and concurrence with creatures in evolutionary processes goes even further with the
origin of man. Divine creation of the human soul at the moment of coming into being of the first
and all subsequent human beings becomes a direct divine intervention, concurrent with the
causality of creatures contributing to the evolutionary nexus of causes that properly dispose
primary matter to be actualized (in-formed) by a human soul. One might go even further and
embrace the alternative explanation, which—necessitating an identification of the cause of unity
of the evolutionary causal matrix—suggests that it is God who brings it about, through his direct
causal agency at the origin of the first exemplar of each new species. Although we are more inclined
to follow Ashley’s emphasis on the polygenic character of causation at work in evolution without
the requirement of specifying a separate cause of the unity of causes involved in evolutionary
transformations, we find the alternative scenario presented here reasonable.
The proposed model has another advantage in distinguishing between primary and
principal causation of God, and secondary and instrumental causality of animate and inanimate
creatures involved in evolution, and in specifying the exact nature of those causes within the
framework of the transcendent and immanent orders of causation. Moreover, our main purpose
was to explain the character of divine and creaturely agency in evolution within the context of the
Aristotelian-Thomistic metaphysics and theology, which gave origin to the distinctions both
between primary and secondary, and between principal and instrumental types of causes. At the
same time, we hope our analysis will prove helpful for other proponents of theistic evolution who
make reference to secondary causation in their explanation of evolutionary changes. We hope our
research presented here will thus contribute to the ongoing conversation on divine action in various
types of transformism (physical, chemical, biological, social, etc.).

37
Finally, the proposed model of divine action in evolution introduces an important revision
and refinement of Aquinas’s view of creation. (1) It puts an emphasis on the fact that the initial act
of creation is restricted to the creatio ex nihilo of the most basic physical matter of the elements.
(2) It clarifies the distinction and relation between creatio ex nihilo and generation. (3) It perceives
the continual and ongoing processes of micro- and macro-evolution as belonging to the work of
adornment (opus ornatus), whose subsequent stages are not limited to the closed and past time
interval but extend through the entire history of the universe. (4) It acknowledges that the
perfection of the universe can grow daily, not only with regard to the number of individuals, but
also with regard to the number of species. (5) It holds that the origin of species occurs through
“production” (productio) from pre-existing matter with ancestry, in a process of universal common
descent, in which God’s agency concurs with the secondary and instrumental causation of
creatures. (6) It does not require a direct divine intervention in the origin of a new plant or animal
species (except for the human species) or reinterprets the nature of such an intervention as bringing
unity to the causally polygenic and extended-in-time processes of an evolutionary transition. We
find these clarifications and changes legitimate within the Aristotelian-Thomistic system of
philosophy and theology, which proves its flexibility and relevance within the context of
contemporary science.
Acknowledgements:
I would like to thank the reviewers and editors of the article for the ACPQ for all substantive and
linguistic comments and suggestions. Many thanks to Michael Dodds, O.P., and Krzysztof Ośko,
O.P. for their valuable insights and intuitions shared at the early stages of my reflection on the
topics covered in this article. I also found helpful comments and questions received from the
audience of the public presentation of the core ideas of this paper at the Francisco Ayala Center for
Theology and the Natural Sciences in Berkeley, CA, in April of 2017.

38
Abbreviations
Abbreviations for the works of Aristotle
De part. De partibus animalium (On the Parts of Animals)
Meta. Metaphysica (The Metaphysics)
Phys. Physica (The Physics)
Abbreviations for the works of St. Thomas Aquinas
In De an. In Aristotelis librum De anima commentarium
In Meta. In Metaphysicam Aristotelis commentaria
In Phys. In octo libros Physicorum Aristotelis expositio
In Sent. Scriptum super libros Sententiarum
Q. de pot. Quaestiones disputatae de potentia
Q. de ver. Quaestiones disputatae de veritate
Quod. Quaestiones quodlibetales
SCG Summa contra gentiles
ST Summa theologiae
Super de causis Super librum De causis expositio