St. Thomas Aquinas on Intelligent Design
Robert C. Koons and Logan Paul Gage
Abstract: Recently, the Intelligent Design (ID) movement has challenged the claim
of many in the scientific establishment that nature gives no empirical signs of having been deliberately designed. In particular, ID arguments in biology dispute the
notion that neo-Darwinian evolution is the only viable scientific explanation of
the origin of biological novelty, arguing that there are telltale signs of the activity
of intelligence which can be recognized and studied empirically. In recent years,
a number of Catholic philosophers, theologians, and scientists have expressed
opposition to ID. Some of these critics claim that there is a conflict between the
philosophy of St. Thomas Aquinas and that of the ID movement, and even an
affinity between Aquinas’s ideas and theistic Darwinism. We consider six such
criticisms and find each wanting.
T
he Intelligent Design (ID) movement—which includes figures such
as Phillip E. Johnson, William A. Dembski, and Michael Behe—has
challenged the claim of many in the scientific establishment that
nature gives no empirical signs of having been deliberately designed. In particular,
ID arguments in biology (on which this paper will focus) dispute the notion that
neo-Darwinian evolution is the only viable scientific explanation of the origin of
biological novelty.1 Defenders of ID argue that there are telltale signs of the activity
of intelligence that can be recognized and studied empirically, such as the “specified
complexity” of DNA or the “irreducible complexity” of micro-biological systems.
In recent years, a number of Catholic intellectuals (philosophers, theologians, and
scientists) have joined with philosophical naturalists in attacking the scientific
bona fides of ID. Some of these Catholic critics have claimed that there is a conflict
between the philosophy of St. Thomas Aquinas and that of the ID movement, and
even an affinity between Aquinas’s ideas and theistic Darwinism.
These critics include:
Edward T. Oakes, S.J., a theologian at University of St. Mary of the Lake;
Edward Feser, a philosopher at Pasadena City College;
Francis J. Beckwith, a philosopher at Baylor University;
©
2012, Proceedings of the ACPA, Vol. 85
DOI: 10.5840/acpaproc2011858
pp. 79–97
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Stephen M. Barr, a physicist at the University of Delaware;
and Michael W. Tkacz, a philosopher at Gonzaga University.
The critics have offered six major objections to ID from a (purportedly)
Thomistic perspective.2
1. ID has a materialistic, mechanistic or modernist conception of life/science
and consequently mis-describes God’s act of creation by using the model
of a human artisan.
2. ID fails to take into account the pervasive immanence of God’s activity in
creation and so wrongly argues for discrete interventions. Aquinas requires
no such interventions and recognizes God’s use of secondary causation.
3. Aquinas’s design argument is superior to that of ID, because he appeals
only to the regularity of nature. Complexity is, and should be irrelevant,
contrary to the thrust of the ID movement.
4. While ID focuses on probabilities and inferences to the best explanation,
Thomists have no need of such devices. The arguments of Aquinas establish
their conclusions with deductive certainty. Besides, end-directed function
without an intelligent cause is not just improbable, as ID theorists suppose,
but metaphysically impossible.
5. Dembski’s three-part filter (necessity, chance, or design) is flawed, since
God can use both necessity and chance in creating.
6. Design and teleology belong to a priori metaphysics, not to empirical science.
We’ll take these criticisms up one at a time.
1. Is ID “Materialistic,” “Mechanistic” or “Modernist”?
Oftentimes, the critics are unclear as to what they mean by this charge. There
are several possibilities. The charge of mechanism might mean that ID proponents
accept the modern rejection of formal and final causation in favor of efficient and
material analyses. First, note that this criticism is certainly true of Darwinian theory,
which seeks to explain the diversification of life via solely material processes of
mutation and differential reproduction. Yet, one rarely sees the critics’ ire directed
toward Darwinism. Second, given that ID seeks signs of intelligent causation/agency,
it is not at all apparent that this criticism hits the mark. Take Stephen C. Meyer’s
argument for intelligent design (Meyer 2009). His argument, inspired by Polanyi
(1967), focuses on the formal properties of DNA which go beyond the mere physical
arrangement of molecules. This semantic content points beyond itself to the only
currently known cause of semantic content: minds. Meyer’s focus, unlike that of
the Darwinians, is thinking scientifically about the properties of life beyond those
of physics and chemistry. Meyer may not be doing Thomistic philosophy, but if his
argument holds, it may well open the door to renewed thinking about formal and
final causation—even within the sciences.
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81
By this charge, however, some critics seem to have reductionism in mind.
But in the debate over the origin of the informational content of DNA, clearly, the
Darwinians are the reductionists. In contrast to ID proponents, Darwinians, by and
large, rarely consider (immaterial) information content as a separate entity to be
studied scientifically and philosophically. They are focused on bottom-up causation
and have reduced life to physics and chemistry alone. The centrality of information
to the ID paradigm is an important link to the Aristotelian and Thomistic tradition.
The very word points back to the centrality of the concept of form in Aristotle’s
system and to its irreducibility to matter.
Furthermore, ID proponents have been a lonely voice decrying the reductionistic approach to life. ID proponents argue that life is not matter only but also
needs immaterial information. This information exists both inside and outside of
the DNA (Meyer 2009, 473–477; Sternberg forthcoming). Organismal parts are
integrated into coordinated systems in a top-down fashion where multiple parts must
be present for function and survival (Behe 1996; 2007). And whereas Darwinians
often reduce life not merely to DNA, but to only coding DNA, ID proponents
argue that organismal structures are designed with a purpose. The Darwinian myth
of so-called “Junk DNA” is just that—a myth (Wells 2011, 89–96).
Some critics seem upset that Michael Behe would refer to some micro-biological
systems as being composed of “molecular machines” (Behe 1996). But these criticisms
fail to recognize that St. Thomas himself often used analogies between living things
and man-made artifacts. In fact, for Thomas, “all creatures are related to God as art
products are to an artist, as is clear from the foregoing. Consequently, the whole
of nature is like an artifact of the divine artistic mind” (SCG 3.100).3 Behe and
others in the ID movement—unlike their Darwinian counter-parts (e.g., Dawkins
2006)—have not forgotten that living creatures are much more than machines or
human artifacts.
By arguing that (at least) some features of the universe are best explained
by intelligent rather than mere material and efficient causes, ID proponents are
reintroducing teleology into the study of nature rather than accepting the antiThomistic, Baconian partition of academic disciplines.4 ID proponents claim to be
doing science under a broad definition of science as the systematic study of nature
via careful observation.5 They do this not, as some Thomists fear, because they
have conceded that all knowledge is ultimately empirical knowledge, but because
nineteenth-century science drove teleology out of nature more by definition than
by observation.6 To the question of whether there are empirical markers of design in
nature, ID proponents say yes, and Darwinists say no. To classify two projects with
different answers to the same question as different disciplines is unwarranted, and,
in our scientistic culture, it puts ID at an unnecessary rhetorical disadvantage. That
said, ID proponents have never disowned philosophical knowledge. ID proponents
are not afraid to be classified as doing philosophy, so long as other equivalent theories
are also so categorized.7
The critics fail to distinguish the essence of the ID movement from various
accidents of argumentation on its behalf. Prudent advocates take into account the
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metaphysical assumptions of their audience. Most contemporary scientists are not
metaphysical Aristotelians. So, it makes sense, arguendo, not to challenge every aspect
of modern scientific thinking at once.
Often, the critics seriously misrepresent the actual position of key ID proponents, especially William Dembski, on this point. Dembski explicitly insists on the
complementarity of physical and intelligent causes, which he describes as two modes
of explanation that are “distinct without prejudicing each other” (Dembski 1999,
90). Dembski himself criticizes the view of American theologian B. B. Warfield on
the grounds that Warfield adopts a “virtually mechanistic account of nature” with
“occasional supernatural intervention,” which Dembski describes as a “muddle” and
“exactly the worst of both worlds” (ibid.). In contrast, Dembski endorses the view
of Charles Hodge, who talked of physical and intelligent causation as “acting in
tandem” (Dembski 1999, 87–88). Dembski insists that intelligent agency does not
violate natural law, while not being reducible to it (Dembski 1999, 89).
Even if the critics were right about Dembski’s allegiance to a modern and unThomistic conception of the physical world, this would be far from sufficient to
prove that ID is essentially anti-Thomistic. The ID movement is, metaphysically
speaking, a big tent. What unifies the members of the movement are commitments
to certain relatively narrow scientific questions, especially: are non-intelligent
mechanisms (including the Darwinian mechanism) capable of explaining the sort
of functionality we find in the biological order? This question is every bit as legitimate from the perspective of Thomism as it is from the perspective of mechanism.
Indeed, it is more legitimate for Thomists, since Thomists are already committed
to the reality of irreducible, intelligent agency.
2. Is Divine Agency Exclusively Immanent?
Thomists rightly call attention to the intrinsic or immanent teleology evident
in living things. However, this focus leaves some Thomists with an Aristotelian
blindspot. Given the temporality of the world (i.e., its finite past), creation—including its irreducible teleology—has an extrinsic source for Aquinas. It’s true that,
had God created an eternal, beginningless universe, creation would have involved
no temporal intervention (Aquinas 1997, 43–44). However, we know, both from
revelation and (now) from empirical evidence, that the universe is not infinitely
old, but had its origin in time. Such origins in time require direct divine action.
Aquinas shows no inclination to avoid miraculous creation. He does not share
the aversion of Enlightenment thinkers like Spinoza to interruptions or discontinuities in the fabric of nature due to direct divine agency. For example, Aquinas believed
that Adam was miraculously created from the “slime of the earth,” and that Eve was
miraculously formed from his rib (ST 1.92.4).
Yet, the critics often recoil at the idea of God “intervening” in nature. Some
seem to think that this implies that God is going against nature—or worse, that
God did not get things right the first time, and so he has to wind his clock back
up.8 In this vein, Michael W. Tkacz wonders if God must poke his finger in the
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83
pre-biotic soup—as though he were an intruder upon foreign territory, rather than
its rightful ruler (Tkacz 2007, 275). But according to Aquinas, miracles are beyond,
but not contrary to, nature:
Since God is prime agent, all things inferior to Him are as His instruments. But instruments are made to serve the end of the prime agent,
according as they are moved by Him: therefore it is not contrary to, but
very much in accordance with, the nature of the instrument, for it to be
moved by the prime agent. Neither is it contrary to nature for created
things to be moved in any way whatsoever [qualitercunque] by God: for
they were made to serve Him. (SCG 3.100)
Fr. Oakes similarly complains that ID makes God into a “Celestial Cell Constructor” or a “Divine Bauplan Architect” (Oakes 2001b, 52). In great contrast to
St. Thomas, we are told, God does not intervene in the natural order to manage
his creation as though he were “the traffic cop of cellular evolution” (Oakes 2001a,
10). “The idea that God swooshed down from heaven 3.5 billion years ago to
toggle some organic-soup chemicals into self-replicating molecules and thereafter,
as occasion warranted, had to intervene to jump-start new species is, quite literally,
incredible.” It is offensive, he thinks, to believe that God “intervenes every now and
again” (Oakes 2001a, 11). Thinking that God intervenes “directly,” we are told, has
“grotesque” “theological implications.” (Oakes 2001a, 8).
But, pace the critics, for Thomas—someone who knew a thing or two about
orthodox theology—lack of “intervention” was no virtue of an account of divine
creation. More than this, according to Thomas, God sometimes purposely acts
contrary to the regular, divinely ordained workings of nature so as to show that he
is the Almighty, that he is not constrained by necessity, but stands above the created
order. Notice that this necessarily involves our observation of God’s “intervention,”
or what Del Ratzsch calls “counterflow” in nature (Ratzsch 2001, 4–6, 41–43).
Thomas writes:
So, if by means of a created power it can happen that the natural order
is changed from what is usually so to what occurs rarely—without any
change of divine providence—then it is more certain that divine power
can sometimes produce an effect, without prejudice to its providence,
apart from the order implanted in natural things by God. In fact, He does
this at times to manifest His power. For it can be manifested in no better
way, that the whole of nature is subject to the divine will, than by the fact
that sometimes He does something outside the order of nature. Indeed,
this makes it evident that the order of things has proceeded from Him,
not by natural necessity, but by free will. (SCG 3.99; see also SCG 2.3)
In addition, Aquinas’s commitment to essentialism rules out most meanings
of “evolution.” According to Aquinas, the semen of one species lacks the natural
power to produce a plant or animal of another species. So, if a new species appears,
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it must come “immediately from God” (ST 1.65.4). Mere chance lacks the power
to jump the gulf from one form to another.
But in 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. To signify
this, Moses prefaces each work with the words, “God said, Let this thing
be,” or “that.” (ST 1.65.4)
As one can see, the critics’ focus on God’s use of secondary causes—or as one
critic revealingly puts it, “the autonomy of nature” (Tkacz 2007, 279)—exaggerates
Thomas’s view of the role of secondary causes regarding the origin of species. True
enough, Thomas (1) rejected occasionalism, holding that creatures are true causes
of their effects, and (2) believed that God created living things to operate according
to the nature he gave them. However, the idea that “God’s action in the world is
exhausted by creation and conservation” was, according to Freddoso, “regarded as
too weak by almost all medieval Aristotelians” (Freddoso 1988, 77). For Thomas
and others, God must also be a concurrent cause of every action. In this sense, it is
misleading for the critics to speak of secondary causes as though this means nature is
just “doing its own thing.” Rather, concurrence entails divine action at every level.9
What is more, Thomas specifically considers and rejects the notion that humanity was created via secondary causation: “The first formation of the human body
could not be by the instrumentality of any created power, but was immediately from
God” (ST 1.91.2). Thomas believes God must be directly involved in the creation
of the first human form. He likens this involvement to direct miraculous activities
like raising the dead to life or restoring sight to the blind. He thinks “the human
soul is ‘breathed into’ the materials of earth” (McMullin 1985, 18). Aquinas was
aware that the Biblical text may indicate some secondary causes in life’s development when it speaks of what the earth brought forth. But for Thomas, one thing is
certain: as regards the human soul, “God had to intervene in a more radical way”
(McMullin 1985, 19).
Moreover, this exaggerated focus on secondary causation is also seen in the utter
absence of Thomas’s doctrine of exemplar causation—a crucial part of Thomistic
metaphysics—in the critics’ writings.10 Given that creatures are a combination of
form and matter, the crucial question as regards the origin of species is where form
comes from. Darwin, denying Aristotelian essentialism, saw organisms’ traits as
accidental properties of living things that change with the winds of time (Darwin
1993, 78–79; Wiker 2002, 218).11 Not so St. Thomas.
An exemplar cause is a type of formal cause—a sort of blueprint; the idea according to which something is organized.12 For Thomas, these ideas exist separately
from the things they cause. For instance, if a boy is going to build a soap-box derby
car, the idea in his mind is separate from the form of the car; yet the car’s form
expresses the idea, or exemplar cause, in the boy’s mind. Herein lies the important
St. Thomas Aquinas on Intelligent Design
85
point: for Thomas, a creature’s form comes from a similar form in the divine intellect.
In other words, the cause of each species’ form is extrinsic. In fact, writes Thomas,
“God is the first exemplar cause of all things” (ST 1.44.3). Creatures do possess the
causal powers proper to the nature God granted them, but creatures most certainly
do not possess the power to create the form of their (or any other) species.
For instance, frog parents have the proper ability to generate tadpoles. They
are able to bring out the natural form that is present in the potentiality of matter.
However, the frog parents cannot create the form frog. After all, Thomas reasons,
if frog parents could create the form frog, they would be the creators of their own
form, and this is clearly a contradiction. Natural things can generate forms of the
same species, but they cannot create the form of a species in general.
More than this, while the critics find intervention unseemly, Thomas specifically considers the idea that God may continue his creative activity with creatures
even after he has given them their form—i.e., intervene creatively—and finds it
perfectly acceptable. Thomas writes:
It is not contrary to the essential character of an artist if he should work
in a different way on his product, even after he has given it its first form.
Neither, then, is it against nature if God does something to natural things
in a different way from that to which the course of nature is accustomed
(SCG 3.100).
Secondary causes are certainly real. But, to repeat, they are not the whole story. Not
only did Thomas not share the critics’ aversion to God’s intervention; his metaphysics is fundamentally opposed to it. For Thomas, “God . . . can cause any effect to
result in anything whatsoever independently of middle causes” (SCG 2.99). Only
God has the power to create novel form. He is truly the creator “of all things visible
and invisible.”
While Aquinas did not shy away from intervention—and even thought God
purposely intervened in a detectable way—ID is a very minimal claim which does
not require intervention. Dembski points out that his heroes, Reid, Paley and
Hodge, “made no appeal to miracles in the production of design” (Dembski 1999,
87). Dembski, following Thomas Reid, locates Cicero and the Stoics as precursors
of ID, despite their lack of belief in a “personal, let alone transcendent and miracleworking, God” (Dembski 1999, 88). Dembski insists that design does not require
miraculous intervention (Dembski 2002, 326), and he admits that it is logically
possible that all design was front-loaded into the Big Bang. As he puts it, “A designer
is not in the business of moving particles but of imparting information” (Dembski
2002, 335). Dembski is not alone. Behe concurs:
the assumption that design unavoidably requires “interference” rests
mostly on a lack of imagination. There’s no reason that the extended
fine-tuning view . . . necessarily requires active meddling with nature.
.. . . One simply has to envision that the agent who caused the universe
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was able to specify from the start not only laws, but much more (Behe
2007, 231).
3. Is Complexity Relevant to an Inference to Design?
Contrary to the claims of Feser (2010, 154–155), the presence of complexity
is relevant to Aquinas’s argument for design:
To signify this, Moses prefaces each work with the words, “God said, Let
this thing be,” or “that,” to denote the formation of all things by the Word
of God, from Whom, according to Augustine [Tract. i. in Joan. and Gen.
ad Lit. i. 4], is “all form and fitness and concord of parts” (ST 1.65.4).
It is impossible for things contrary and discordant to fall into one harmonious order always or for the most part, except under some one guidance,
assigning to each and all a tendency to a fixed end. But in the world we
see things of different natures falling into harmonious order, not rarely
and fortuitously, but always or for the most part. Therefore there must
be some Power by whose providence the world is governed; and that we
call God. (SCG 1.13)
This accords well with Behe’s straightforward definition of design: “Design is simply
the purposeful arrangement of parts” (Behe 1996, 193).
Feser has not shown complexity to be absent from Thomas’s argument for
design. Even if he did, it would only demonstrate that there is more than one kind
of design argument. Thomas’s paradigm for “harmonious order” may well be the
Ptolemaic system of astronomy—hardly a simple picture.
Contemporary readers should keep in mind that with the advance of information science, there exist today even more refined categories of explanation for what
Thomas called “order.” Thomas generally contrasts order—or great or “harmonious”
order—with chaos and disorder. But contemporary ID arguments take advantage of
categories which distinguish relatively simple order (such as is often seen in physics)
from the highly ordered or “specified complexity” such as is seen in DNA (cf. Dembski 1998). In this instance, ID theorists have retained the same basic distinctions
made by Thomas, but accommodated the insights of modern science to strengthen
the conclusion that order requires an intelligent orderer.
4. Is the Use of Probabilities Legitimate in Detecting Intelligence?
Feser (2010, 155) also contends that probabilities are irrelevant to Aristotelian-Thomists’ arguments for the existence of irreducible teleology in nature. But
Thomists surely need to consider the measure of the improbability of chance-generated design simulacra. They are right to assert that it is metaphysically impossible
for something with a real telos to exist apart from the activity of an intelligent cause.
However, it is possible for a “heap” of merely physical things, assembled by chance,
St. Thomas Aquinas on Intelligent Design
87
to mimic real teleology and purpose. We encounter many examples: clouds or rocks
that resemble sculptures of human beings or animals, pancakes that look like profiles
of JFK, etc. We can sensibly ask, is the Old Faithful geyser a living organism, with its
own form and telos, or is its regularity a mere by-product of a chance conjunction of
various geological conditions? To answer these questions with confidence, we must
ask how likely the observed conjunction would be in the absence of a unifying and
ordering immanent form.
To rigorously distinguish between real and merely apparent design, then, it is
best to consult probabilities. It is true that in many ordinary situations, it is unnecessary to consult probabilities to distinguish design from apparent design. In most
cases, we simply perceive design using our reliable faculties to do so (cf. Ratzsch
2003, 107). Dembski himself merely claims to formalize what is involved in everyday
perceptions of design with his notion of specified complexity. But while they may
not be strictly necessary for detecting design, these probability assessments serve to
tighten up our objective certainty regarding perceptions of design. Thus, Dembski’s
work is vital to the modern realization of the Thomistic project.
5. Can God “Use” Chance?
The critics have also taken aim at Dembski’s “explanatory filter” (Barr 2010;
Beckwith 2010, 437–438; Beckwith forthcoming). The usual criticism is that Dembski’s filter implies that things which are attributable to “law” are not attributable
to God’s design. But this is a gross misunderstanding—one the critics should have
noticed, given that Dembski and other ID theorists have consistently supported
design arguments from the fine-tuning of the laws of physics. Dembski has long
noted that law, chance and design are not mutually exclusive categories (Dembski
2004, 93). When detecting design, one might conclude that known laws of nature
are insufficient to produce the phenomenon in question. But this in no way implies
that the known laws are not themselves designed.13
While Dembski’s filter is only one possible way of framing ID arguments—
and not necessary to any such argument—it is interesting that Aquinas seems to
anticipate this tripartite schema: necessity, chance or design. There is one difference
in terminology: Aquinas would speak not of “necessity” or “law of nature,” but of
the powers of natural or created beings. Every effect must be the product either of
some unintelligent agent or of chance or of some intelligent agent. Aquinas follows
the Aristotelian definition of “chance”:
A chance event arises from a coincidence of two or more causes, in that an
end not intended is gained by the coming in of some collateral cause, as
the finding of a debtor by him who went to market to make a purchase,
when his debtor also came to market (SCG 3.74).
Good fortune is said to befall a man, when something good happens to
him beyond his intention, as when one digging a field finds a treasure
that he was not looking for (SCG 3.92).
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According to Thomas, the order of creation, including the distinction of species, is not a result of chance.
And again, the form of anything proceeding from an intellectual and
voluntary agent is intended by that agent. But, as we have already seen,
the universe of creatures has as its author God, who is a voluntary and
intellectual agent. Nor can there be any defect in His power so that He
might fail in accomplishing His intention; for, as we proved in Book I
of this work, His power is infinite. It therefore follows of necessity that
the form of the universe is intended and willed by God, and for that
reason it is not the result of chance. For it is things outside the scope of
the agent’s intention that we say are fortuitous. Now, the form of the
universe consists in the distinction and order of its parts. The distinction
of things, therefore, is not the result of chance. (SCG 2.40)
In fact, nothing in creation is, ultimately (in reference to God), due to chance.
It is further to be observed that good or ill fortune may befall a man as
a matter of luck, so far as his intention goes, and so far as the working
of the prime forces of nature (corpora coelestia) goes, and so far as the
mind of the angels goes, but not in regard of God: for in reference to
God nothing is by chance, nothing unforeseen, either in human life or
anywhere else in creation. (SCG 3.92)
But couldn’t God use a stochastic or chancy process in creating? No, for three
reasons:
1. God does not in fact leave anything up to chance (as just seen in SCG
3.92).
2. God could not leave anything up to chance: every particular contingent fact
depends on God’s providential will, as a matter of necessity (ST 1.22.2).14
3. If a chance process did occur per impossibile, it would be incapable of creating a new form.
Couldn’t God use chance to produce a specific result intentionally? No. By the
Aristotelian (and Thomistic) definition of chance, chance is whatever is caused by a
confluence of causes outside the intention of anyone. So, by definition, God cannot
use chance to produce a specific result. This would make the result both outside
anyone’s intention and inside God’s intention—a self-contradiction.
This is not to say that Thomas thinks it nonsensical to speak of chance or
fortune. Quite the opposite (SCG 100.74). There is contingency in nature. And
chance certainly exists in the sense of interacting causal chains apart from any creature’s intention. But this is chance only in reference to creatures, or perhaps more
accurately, in reference to the limited knowledge of creatures. As Thomas says, “in
reference to God nothing is by chance, nothing unforeseen, either in human life or
anywhere else in creation” (SCG 3.92). As regards God’s creation of creatures, chance
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has no place. Creatures are intended by God, for they come from a corresponding
form in the divine intellect.
Still, there have been clever attempts to integrate divine action with the Darwinian definition of chance. Peter van Inwagen, for instance, claims that chance
processes can be used by an intelligent agent. Van Inwagen correctly points out
that the inference from the chanciness of every part of an ensemble of events to the
chanciness of the whole ensemble commits the fallacy of composition. The individual
events in some set of events can be random, and can be random because the agent
made them so, in order to fulfill some purpose. For example, an agent can make use
of an intentionally random sampling of points in order to estimate the area under a
curve (van Inwagen 2003, 353–354). Van Inwagen’s observation is correct, but not
relevant to the case in which God is the agent, at least not according to Aquinas.
God does intend each and every natural event, not merely some global pattern.
Van Inwagen also asks what “random” means in the context of Darwinism.
His answer, on behalf of Darwinian biologists, is to claim that “randomness” merely
refers to a lack of correlation between the probability of the occurrence of a mutation
and its functionality or adaptiveness. This is compatible with frequent, purposeful
intervention by God, guiding the process of evolution toward a desired result.
We have three responses. First, van Inwagen is right that neo-Darwinians often
claim that the randomness they have in mind when referring to “random mutations” only means that there is no correlation between mutations and beneficial
adaptations. But this could be taken in two ways. On one hand, it might mean that
specific mutations do not happen because they are adaptive. On the other, it might
mean that, on the whole, there is no correlation between mutations and adaptive
functions. Notice, however that the former understanding is not amenable to van
Inwagen’s argument. In his postulation of divine action the guided mutations would
indeed happen because God knew that they were adaptive. The latter interpretation
is more amenable to van Inwagen’s argument, but this sort of evolution would not
be Thomistic. It faces both the challenge of essentialism (seen earlier) and the fact
that Thomas thought divine action would be evident to all. Plus, if God is actively
intervening at critical points in the history of life with sufficient frequency to
shape the course of evolution, what grounds do we have for thinking that his doing
so would not induce some correlation between the occurrence of mutations and
their adaptiveness? Prima facie, we would expect some such correlation to result.
In addition, what possible motive would God have to respect the Darwinian nocorrelation constraint?
Second, truth be told, Darwinians typically advance a much stronger claim
than this minimal assertion of a lack of correlation. The whole point of Darwinism
in the first place was to exclude intelligent agency from the details of the process
altogether. As Darwin himself said, “If I were convinced that I required such additions to the theory of natural selection, I would reject it as rubbish . . . I would give
absolutely nothing for the theory of nat. selection, if it require miraculous additions
at any one stage of descent” (Darwin 1991, 345).
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Third, if van Inwagen is correct, God is (inexplicably) acting directly in such
a way as to mimic the power of non-intelligent mechanisms to mimic intelligent
agents. This is not the scientific theory Darwin or the chief neo-Darwinians had
in mind. Not only is it convoluted, but it is drastically removed from the spirit of
Thomas’s claim that God sometimes acts apart from the natural order so as to reveal
his power in a detectable fashion. (SCG 3.99)
6. Is Design Empirically Detectable?
Critics like Feser also contend that “Aquinas’s argument is intended as a metaphysical demonstration,” not as a “quasi-scientific empirical hypothesis” like that on
offer from ID (Feser 2009, 111). To be sure, there are differences between Thomas’s
Fifth Way and, say, Behe’s argument for irreducible complexity. But Aquinas clearly
thought that the activity of intelligence can be empirically detected. For instance,
there could be no spontaneous generation of living forms without intelligence. Thus:
It was laid down by Avicenna that animals of all kinds can be generated
by various minglings of the elements, and naturally, without any kind
of seed. This, however, seems repugnant to the fact that nature produces
its effects by determinate means, and consequently, those things that are
naturally generated from seed cannot be generated naturally in any other
way. It ought, then, rather to be said that in the natural generation of
all animals that are generated from seed, the active principle lies in the
formative power of the seed, but that in the case of animals generated
from putrefaction, the formative power is the influence of the heavenly
bodies. (ST 1.71.1)
Aquinas refers to the formative power of the heavenly bodies precisely because
these bodies were thought to be animated by celestial or angelic intelligences. Thus,
Aquinas affirms the soundness of inferring intelligent design from the spontaneous
generation of life. But this is not the only place in which it is clear that Aquinas
thought that the activity of intelligence could be empirically detected.
Everything that tends definitely to an end, either fixes its own end, or has
its end fixed for it by another: otherwise it would not tend rather to this
end than to that. But the operations of nature tend to definite ends: the
gains of nature are not made by chance: for if they were, they would not
be the rule, but the exception, for chance is of exceptional cases. Since
then physical agents do not fix their own end, because they have no idea
of an end, they must have an end fixed for them by another, who is the
author of nature. But He could not fix an end for nature, had He not
Himself understanding. (SCG 1.44)
The fifth way is taken from the governance of the world. We see that
things which lack intelligence, such as natural bodies, act for an end, and
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this is evident from their acting always, or nearly always, in the same way,
so as to obtain the best result. Hence it is plain that not fortuitously, but
designedly, do they achieve their end. Now whatever lacks intelligence
cannot move towards an end, unless it be directed by some being endowed
with knowledge and intelligence; as the arrow is shot to its mark by the
archer. Therefore some intelligent being exists by whom all natural things
are directed to their end; and this being we call God. (ST 1.2.3)15
Often the critics implicitly accept the identification of science with methodological naturalism: according to the critics, immanent teleology cannot be
empirically identified. Since ID theorists seek to frame arguments that fall within
the purview of natural science, the critics erroneously jump to the conclusion that
ID theorists have unwittingly embraced naturalism or mechanism (Feser 2009,
110–115; Beckwith 2010, 435–439). Once we recognize that ID theorists believe
teleology to be empirically detectable (as did Aristotle and Aquinas), this bizarre
misattribution to them of “mechanistic philosophy” falls flat.
In addition, the critics import into their interpretation of Aquinas an Enlightenment dichotomy of philosophy from empirical science.16 Aquinas was no
Rationalist, like Descartes or Spinoza. Physics and metaphysics formed a continuum
for Aristotelians like Aquinas. Both are equally rooted in the knowledge that comes
to us through the senses. Aquinas assigns a very modest role to purely a priori (in
the Kantian sense) or introspectible axioms.
Thomists are right to insist that knowledge can be derived from philosophy,
theology and other disciplines—not merely from science. But, contrary to the critics,
ID proponents have never claimed otherwise (Beckwith 2009, 443–444). In fact, ID
proponents have fought this misconception tooth and nail (Johnson 1995, 89–131;
Pearcey 2004). They insist their work is scientific, not because it must be scientific
to be knowledge, but because it is scientific under any neutral definition. When
some critics take issue with ID’s claim to be scientific, they unwittingly concede
an anti-theistic definition of science (Plantinga 2001, 341). What metaphysically
neutral rule would keep scientists from searching for empirical signs of purpose and
agency?17 Why should the Thomist concede that God’s design cannot be empirically
detectable? Why not remain open-minded, especially when Aquinas himself thought
that God’s acts are detectable via observation of the natural world?
Conclusion: The Thomist Critics’ Central Misunderstanding
The Thomistic critics of ID understand neither ID nor the heart of Darwinian
evolution. Darwinism and Neo-Darwinism are instances of reductive materialism.
That’s their whole point, their raison d’être. Again, Darwin was emphatic that natural
selection was worthless if it needed to be supplemented by divine action. Natural
selection was meant to be a designer substitute; nature could, given enough time,
mimic the effects of intelligence.
Darwinism contends that the ultimate cause of the origin of all biological
functionality is the result of chance genetic mutations. Natural selection is not a
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second, parallel cause. It is not a force or mathematically precise natural law like
gravity. Forces may be guided or unguided. Laws are teleological. In contrast, natural
selection merely means that living things die and reproduce at different rates; this
in turn affects the composition of the next generation. Natural selection merely
increases nature’s probabilistic resources by progressively fixing “beneficial” innovations in a much larger population. Chance and chance alone must be responsible for
the emergence of each new form and function. The Darwinian process as a whole
is impersonal, non-intentional, and reduces the evolutionary process to material
and efficient causes. If Darwinism is correct, the Thomist must hold that mere
material and efficient causes have the power to, and did in fact, give rise to formal
and final causes.
If Darwinism is true, then Thomism must be false. Thomists claim that the
biological world is populated by things with irreducible biological natures, each of
which must be the product of an intelligent cause. ID is not a competing metaphysical system for the simple reason that it is not a metaphysical system. With respect
to the origin of species, at least, Thomism is a form of intelligent design, not an
alternative to it.18
University of Texas at Austin
Baylor University
Notes
1. We focus on biological design arguments, even though proponents have made arguments in various scientific disciplines, simply because these arguments are the center of the
critics’ ire. The critics show little awareness of design arguments in other disciplines (e.g.,
Gonzalez and Richards 2004).
2. The critics, taken collectively, have leveled these six objections. It should not be
implied, however, that each ID-critic endorses each objection.
3. Cardinal Joseph Ratzinger, now Pope Benedict XVI, agrees: “If creation cannot be
recognized as the metaphysical middle term between nature and artificiality, then the plunge
into nothingness is unavoidable” (Ratzinger 1995, 93). Thomas’s Summa Contra Gentiles
will be abbreviated SCG and his Summa Theologiae ST. All SCG quotations are from the
translation of Anton C. Pegis, et al., while all ST quotations are from the Fathers of the
English Dominican Province translation.
4. This should not be taken as implying that ID proponents think teleology, natures,
essences, or universals cannot be grasped in non-empirical ways (contra Beckwith 2009,
443).
5. Such a broad definition is easily justified given the well-acknowledged failure of
proposed demarcation criteria (Laudan 1982).
6. Fortunately, there has been some recent movement away from principled methodological naturalism, even among metaphysical naturalists. As one recent paper argues,
St. Thomas Aquinas on Intelligent Design
93
“Evolutionary scientists are on firmer ground if they discard supernatural explanations on
purely evidential grounds, and not by philosophical fiat” (Boudry et al. 2010, 241).
7. Stephen C. Meyer, for instance, argues persuasively for the scientific status of ID
and the methodological equivalence of ID and Darwinian theory. He insists most strongly,
however, not that ID is science but that if it is not going to be called science, then neither
should theories with the same logical structure. He writes:
Perhaps, however, one just really does not want to call intelligent design a scientific
theory. Perhaps one prefers the designation ‘quasi-scientific historical speculation
with strong metaphysical overtones.’ Fine. Call it [ID] what you will, provided
the same appellation is applied to other forms of inquiry that have the same
methodological and logical character and limitations. In particular, make sure
both design and descent [Darwinian theory] are called ‘quasi-scientific historical
speculation with strong metaphysical overtones.’ (Meyer 2000, 193)
8. Because the critics often claim that ID, in great opposition to St. Thomas, views
God as a Clockmaker, the following passage is noteworthy:
Accordingly, in all things moved by reason, the order of reason which moves
them is evident, although the things themselves are without reason: for an arrow
through the motion of the archer goes straight towards the target, as though it
were endowed with reason to direct its course. The same may be seen in the
movements of clocks and all engines put together by the art of man. Now as
artificial things are in comparison to human art, so are all natural things in comparison to the Divine art. And accordingly order is to be seen in things moved
by nature, just as in things moved by reason, as is stated in Phys. ii. And thus
it is that in the works of irrational animals we notice certain marks of sagacity,
in so far as they have a natural inclination to set about their actions in a most
orderly manner through being ordained by the Supreme art.” (ST 1-2.13.2) [all
underlined emphases are ours]
While there is surely a helpful distinction between natural and artificial objects, Thomas is
not averse to viewing God as acting analogously to a human artificer, even a clockmaker.
For Thomas, it is evident that intelligent agency lies behind the order seen in natural entities
which lack reason. Such order is the exclusive hallmark of rational agents. ID proponents,
with the knowledge modern science affords, extend such reasoning to, among other things,
the highly ordered nature of DNA and the microbiological world.
9. God and his creatures are both wholly causes of the same events, not partial causes
(SCG 3.70).
10. Even in the one instance in which exemplar causation is alluded to, Edward Feser
fails to notice its centrality to the debate about whether God “intervenes” in nature (Feser
2010). Much of what follows in this discussion of exemplar causation is also to be found in
Gage (2010).
11. Neo-Darwinians also advocate a nominalist conception of species (Dawkins 2006,
34).
12. For the most extensive treatment of Thomas’s doctrine of exemplar causation to
date, see (Doolan 2008).
13. One must be careful, however, as assuming that the laws of nature are designed
when making an ID argument may beg the question (cf. Richards 2010, 254–258).
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14. Thomas is quite clear that everything is subject to the providence of God. He writes:
But the causality of God, Who is the first agent, extends to all being, not only as
to constituent principles of species, but also as to the individualizing principles;
not only of things incorruptible, but also of things corruptible. Hence all things
that exist in whatsoever manner are necessarily directed by God towards some
end; as the Apostle says: “Those things that are of God are well ordered (Romans
13:1). Since, therefore, as the providence of God is nothing less than the type
of the order of things towards an end, as we have said; it necessarily follows that
all things, inasmuch as they participate in existence, must likewise be subject to
divine providence. It has also been shown (Q. 14, A. 6, 11) that God knows all
things, both universal and particular. And since His knowledge may be compared to the things themselves, as the knowledge of art to the objects of art, all
things must of necessity come under His ordering; as all things wrought by art
are subject to the ordering of that art.
And further:
So far then as an effect escapes the order of a particular cause, it is said to be casual
or fortuitous in respect to that cause; but if we regard the universal cause, outside
whose range no effect can happen, it is said to be foreseen. Thus, for instance,
the meeting of two servants, although to them it appears a chance circumstance,
has been fully foreseen by their master, who has purposely sent to meet at the
one place, in such a way that the one knows not about the other. (ST 1.22.2)
In this way, “The order of divine providence is unchangeable and certain, so far as all things
foreseen happen as they have been foreseen, whether from necessity or from contingency”
(ST 1.22.4).
15. Often the critics complain that Thomas’s Fifth Way is not really a design argument
at all. Feser (2008; 2010), for instance, pits ID arguments, and even those of William Paley,
against Thomas’s Fifth Way. Supposedly, Paley is concerned with the end-directedness of
things like watches, but Aquinas is only interested in the “immanent end-directedness” of
natural things. But, as Marie George points out, “Feser’s overemphasis on the difference in
natural and artificial teleology results in” this error (George 2010, 446). Feser’s “emphasis on
the intrinsic directedness to an end of natural things leads him [Feser] to be unduly critical of
Paley’s argument, when in fact there are many striking similarities between Paley’s argument
and the Fifth Way” (George 2010, 449). Both Paley and Aquinas see the end-directedness
of artifacts as an extension of the intelligence of intelligent agents. So too, they both see the
end-directedness of living things as pointing to an intelligent being. In this regard, note that
Feser (2011, 4) argues that Paley’s argument (and, by extension, ID arguments) are “incompatible” with Thomas’s metaphysics of immanent finality. Yet this incompatibility claim is
unsupported by Feser. He points to what he takes to be several differences between the two
types of arguments, but it would take a contradiction, not mere differences, to support an
incompatibility claim.
16. For more on the critics’ strange amalgamation of Aristotle’s four causes with a
Baconian demarcation of the disciplines, see Richards (2010, 260–270).
17. On methodological naturalism, see Meyer (2000), Plantinga (2001), Ratzsch (2004),
and Menuge (2010).
St. Thomas Aquinas on Intelligent Design
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18. The authors wish to thank Jay Richards, Lydia McGrew and attendees of the 2011
meeting of the American Catholic Philosophical Association (especially Robert Delfino, our
commentator) for their comments and suggestions.
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