Tuesday, March 15, 2011
Thomism versus the design argument
Defenders of “Intelligent Design” theory sometimes accuse their Thomist critics of overstating the differences between Aquinas and William Paley. As we have seen before, their use of Aquinas’s texts is highly dubious. Passages are ripped from context and the general metaphysical assumptions that inform Aquinas’s thinking, and which would rule out the readings the ID theorist would like to give the texts, are ignored. This is not surprising given the ad hoc character of so much ID argumentation. More surprising is Marie George’s strange article about me in the most recent issue of Philosophia Christi. George, like me, is both an Aristotelian-Thomistic (A-T) philosopher and a critic of ID. Yet she too objects to my dissociating Aquinas’s Fifth Way from Paley’s design argument. Why?
That is hard to say. For George concedes that any A-T philosopher must insist on a distinction between natural substances and artifacts insofar as “the parts of natural things are inherently ordered to their ends, whereas the parts of artificial things are ordered by us (and by certain other animals) to ends that they have no tendency to realize.” Indeed, she acknowledges that “it would be incoherent to model natural substances on artifacts in a way that would ignore this difference.” She also allows that there is a crucial difference between a mere craftsman and God insofar as “the craftsman does not give an artifact its nature, but harnesses the natural tendencies of natural things to his end, whereas God… gives things their natures in virtue of which they tend to their ends.” And she grants that “it may well be that Paley had mechanistic tendencies.” In other words, George more or less concedes that Aquinas’s argument and Paley’s differ in just the ways I and other Thomists have always said they do.
So what exactly is her problem with what I have said? The closest we get to an answer is George’s suggestion that on my view, the way God makes natural things “must be other than [by] employing intelligence.” This is bizarre. I have, of course, never said or implied any such thing. Indeed, I devote many pages of both The Last Superstition and Aquinas to defending the Fifth Way as a demonstration of the existence of a divine ordering intelligence. No one denies that both Aquinas and Paley argue for an intelligent cause of the order in the world. What A-T philosophers (other than George) object to is the way Paley argues for this conclusion (a way which is incompatible with A-T metaphysics) and the anthropomorphic construal of “intelligence” implicit in his position (which is incompatible with classical theism). I have addressed these issues at length in a series of posts, to which the interested reader is directed.
There are many other problems with George’s article, which I address in a forthcoming reply. For now let us note just how eccentric her view is, as is the view of ID defenders who think they can assimilate Aquinas’s Fifth Way to the “design argument” put forward by the likes of Paley, Newton, Boyle, and other early modern writers who were keen on putting natural theology on a new, non-Aristotelian foundation. Here, in no particular order, are some passages on the subject from various twentieth-century writers on Thomism:
Maurice Holloway, S. J., An Introduction to Natural Theology, pp. 146-47:
We should be careful not to confuse the fifth way of St. Thomas Aquinas, which argues from the existence of order in the universe to the existence of an infinite intelligence, with Paley’s argument from design. In the latter’s argument the universe is seen as a complicated and intricate machine… [and he] reasons, by way of analogy, to the existence of a divine watchmaker, or supreme architect of the universe. This argument from design, as given by Paley and unfortunately repeated in many books on Christian apologetics, does not prove the existence of God. An architect of the universe would have to be a very clever being, but he would not have to be God… Many of the objections directed against what some writers believe is the fifth way of St. Thomas are really directed against the watchmaker of Paley. St. Thomas’s proof is entirely different. It is grounded in the metaphysics of finality…
Etienne Gilson, God and Philosophy, p. 142:
Simple-minded metaphysicians have unwillingly led agnostics to believe that the God of natural theology was the “watchmaker” of Voltaire, or the “carpenter” of cheap apologetics…. Being men, we can affirm God only on anthropomorphic grounds, but this does not oblige us to posit Him as an anthropomorphic God.
John Wippel, The Metaphysical Thought of Thomas Aquinas, p. 480:
While the fifth way is sometimes confused with an argument based on order and design and the need for a supreme designer, Thomas’s text makes it clear that he really has in mind an argument based on final causality in nature.
Joseph Owens, An Elementary Christian Metaphysics, p. 349:
This argument [the Fifth Way] is clearly not the argument from design, made notorious by Paley… Paley’s argument is only an analogy, a probable argument. It is not a metaphysical demonstration… Paley merely multiplies instances upon instances of design in nature in order to drive home the impression… that a designer is required. The starting point of St. Thomas’s fifth way, on the other hand, is not that things show design, but rather that something is being done to them, namely, that they are being directed to an end by an efficient cause.
Joseph Owens, “Aquinas and the Five Ways,” in St. Thomas Aquinas on the Existence of God, pp. 136-37:
The “fifth way”… is hardly the one from design that has been made notorious by Kant and Paley. The presence of design in the universe is not the operative feature. It is rather the directing according to design, for this directing has to come ultimately from an immobile and self-necessary principle. In reply to the objection that agents less than God could ultimately account for the directing, Aquinas answers: “But all things mobile and capable of failing have to be accounted for by a first principle that is immobile and that is necessary by reason of its own nature, as has been shown” (ST, I, 2, 3, ad 2m).
Fr. Ronald Knox, Broadcast Minds, pp. 52 and 222:
The whole traditional theology of Europe presupposes the Five Proofs [of Aquinas], or some modification of them, as the basis of belief in God, and does not appeal for a moment to any revelation, in Scripture or out of it, for the purpose. Which makes it all the more extraordinary that Professor Huxley, in demolishing the whole edifice of theism, makes no reference to the Five Proofs, and shows no consciousness that they have ever been urged. He has heard of Paley, apparently, and makes fun of his argument from design, with a confidence which would be better justified if the champions of natural selection had managed to get rid of adaptation altogether; and it is presumably from the same author that he gets the deistic notions stigmatized on the following page… But when he characterizes the God of Deism, the Winder-up of a mechanical universe, as “much more shadowy, far, and remote than the God of the Middle Ages”, I wonder whether he has the slightest idea what he is talking about? Certainly his acquaintance with St. Thomas can hardly be intimate.
[Langdon-Davies’s] disproof of the existence of God labours, even more signally than Professor Huxley’s, from an ignorance of the proofs. Not only is he unaware, like Professor Huxley, that there is a five-fold proof of the existence of God traditional in the Christian Church… He concentrates on the three feeble arguments that are known to him; that from experience, that from design (in the manner of Paley), and that from the inerrancy of Scripture!
Herman Reith, The Metaphysics of St. Thomas Aquinas, p. 198:
[The Fifth Way] is strictly metaphysical and is not limited to the examples given by St. Thomas. It is based upon the principle of final causality that is as universal in its application as the principle of identity. It is sometimes interpreted as the proof from order and design in the universe, taken in the physical sense in which the regularity of movement of the parts of the universe is emphasized. In this conception God’s role is that of a giant watchmaker who has put things together in such a way that one must recognize it as the work of a superior intelligence.
The danger in such a simplification of the proof is that the examples used and the interpretation given them prevents the argument from rising to the metaphysical level where it belongs. To insist on examples from astronomy, biology, or any other physical science is grist for the mill of the mechanist. For him the natural causes hold enough of an explanation. Until the argument rises above the order of the physical universe, it cannot conclude to anything more than the existence of some kind of intelligence and power with which we have not yet become acquainted. Future investigation might conceivably reveal that there are powers of intelligence in the universe that we now have no evidence for.
R. P. Phillips, Modern Thomistic Philosophy, Volume II, p. 290:
[The Fifth Way] proceeds from the ordered multiplicity of the world to an ordering intelligence. Whether we are to call it the argument from design depends on what is meant by that name, for it certainly is not the same as that which is often associated with the name of Paley.
John F. McCormick, S. J., Scholastic Metaphysics, Part II: Natural Theology, p. 75:
The teleological argument [is] not an argument from analogy… It is true that the argument has at times been presented in the form of a mere analogy, as in Paley’s example of the watch… But the proof is quite independent of this analogy.
Cardinal Mercier, “Natural Theology or Theodicy” in Cardinal Mercier, et al., A Manual of Modern Scholastic Philosophy, Volume II, pp. 53-54:
The proof we have just developed [i.e. the Thomistic argument from order] is not merely an argument from analogy. If some are inclined to think so, the reason is to be found in the faulty exposition given of this proof by certain authors. They argue that we judge the intellectual capacity of our fellow-men by the adaptation of the means they choose to their ends, that order or adaptation is an indication of intelligence; that the universe manifests supreme order; therefore, etc. Argument of this kind need cause no misgiving… Our argument is based not on analogy but on the principle of sufficient reason…
[O]ther arguments which are not infrequently brought forward… [to the effect] that life has had a commencement on the earth; that a simple intrinsic evolution of matter is not capable of accounting for vegetable life in the first place, and then for sensitive life and still less for intellectual life… These and kindred considerations of a scientific nature… by themselves they have no cogency unless supported by the philosophical, metaphysical argument which demonstrates that this principle of explanation taken to its last analysis must be pure Actuality, necessary Being, first Cause, subsistent Perfection, and highest Intelligence.
Henri Renard, S.J., The Philosophy of God, p. 48:
With St. Thomas, even if there were only one finite nature, we could argue to and prove with metaphysical certitude the existence of a being that is its own end… With these authors, on the contrary, such is not the case. They argue, not from the appetite of a nature, but from the admirable complexity of the created world… Just as, they reason, the complexity of a watch demands a watchmaker gifted with some intelligence, just as the order of the city demands some capable policemen, just as the skyscraper supposes some architect or other, so a fortiori does this marvelous order of the world postulate a God.
This is an impressive argument and quite satisfying to a certain type of mind. We should like to state, however, (1) that it is by no means the Fifth Way of St. Thomas; (2) that, while we are willing to grant that this argument establishes a God who is a super-watchmaker, a super-policeman, a super-architect, we cannot help but wonder whether such a super-being is its own end, because it is its own “To Be” or, in other words, whether such a being is God.
Christopher F. J. Martin, Thomas Aquinas: God and Explanations, pp. 180-82:
One of the things that has happened between Aquinas and ourselves has been the growth of a general disbelief in explanation in terms of what things are for [i.e. final causes]. This is partly the result of a failure to understand what it is to explain something in terms of what it’s for, and partly the result of the rather curious psychological phenomenon of the near-universal acceptance of what is really a rather poor argument for the existence of God, the argument from design.
The argument from design had its heyday between the time of Newton and the time of Darwin, say, a time in which most people apparently came to see the world as a minutely designed piece of craftsmanship, like a clock. It is no coincidence that the most famous presentation of the argument from design actually compares the world to a clock: it is known by the name of Paley’s watch…
The Being whose existence is revealed to us by the argument from design is not God but the Great Architect of the Deists and Freemasons, an impostor disguised as God, a stern, kindly, and immensely clever old English gentleman, equipped with apron, trowel, square and compasses. Blake has a famous picture of this figure to be seen on the walls of a thousand student bedrooms during the nineteen-seventies: the strong wind which is apparently blowing in the picture has blown away the apron, trowel and set-square but left him his beard and compasses. Ironies of history have meant that this picture of Blake’s is often taken to be a picture of God the Creator, while in fact Blake drew it as a picture of Urizen, a being who shares some of the attributes of the Great Architect and some of those of Satan.
The Great Architect is not God because he is just someone like us but a lot older, cleverer and more skilful. He decides what he wants to do and therefore sets about doing the things he needs to do to achieve it. God is not like that. As Hobbes memorably said, "God hath no ends": there is nothing that God is up to, nothing he needs to get done, nothing he needs to do to get things done. In no less lapidary Latin, Aquinas said "Vult ergo Deus hoc esse propter hoc; sed non propter hoc vult hoc". In definitely unlapidary English we could say: The set-up, A-for-the-sake-of-B is something that God wants; but it is not that God wants B and for that reason wants A. We know that the set-up A-for-the-sake-of-B is something that God wants, because it is something that exists, and everything that exists, exists because of God’s will. But it is simply profane to think that you can infer from that the unfathomable secrets of the inside of God’s mind and will. Acorns for the sake of oak trees, to repeat an example of Geach’s, are definitely something that God wants, since that is the way things are. But it is not that God has any special desire for oak trees (as the Great Architect might), and for that reason finds himself obliged to fiddle about with acorns. If God wants oak-trees, he can have them, zap! You want oak trees, you got ’em. "Let there be oak trees", by inference, is one of the things said on the third day of creation, and oak trees are made. There is no suggestion that acorns have to come first: indeed, the suggestion is quite the other way around. To "which came first, the acorn or the oak?" it looks as if the answer is quite definitely "the oak". In any case, what’s so special about oak trees that God should have to fiddle around with acorns to make them? God is mysterious: the whole objection to the great architect is that we know him all too well, since he is one of us. Whatever God is, God is not one of us: a sobering thought for those who use "one of us" as their highest term of approbation.
The argument from design fails, then, because [as Martin argues earlier in the book] it is an argument from ignorance, because it confuses the final and efficient modes of explanation, and because even if it succeeded it would not prove the existence of God but of some Masonic impostor. But like other bad arguments, its defeat and death has left it to wander the world like a ghost, oppressing the spirits of those who are looking for other and better arguments.
And for good measure, here’s one more passage, this time from a non-Thomist. See if you can guess who it is:
Throughout the Christian era, theologians have argued that nature exhibits features which nature itself cannot explain but which instead require an intelligence beyond nature… Aquinas’s fifth proof for the existence of God is perhaps the best known of these.
With the rise of modern science in the seventeenth century, design arguments took a mechanical turn. The mechanical philosophy that was prevalent at the birth of modern science viewed the world as an assemblage of material particles interacting by mechanical forces. Within this view, design was construed as externally imposed form on preexisting inert matter. Paradoxically, the very clockwork universe that early mechanical philosophers like Robert Boyle (1627-1691) used to buttress design in nature was in the end probably more responsible than anything for undermining design in nature. Boyle (in 1686) advocated the mechanical philosophy because he saw it as refuting the immanent teleology of Aristotle and the Stoics, for whom design arose as a natural outworking of natural processes…
Over the subsequent centuries, however, what remained was the mechanical philosophy and what fell away was the need to invoke miracles or God as designer. Henceforth, purely mechanical processes could do all the design work for which Aristotle and the Stoics had required an immanent natural teleology and for which Boyle and the British natural theologians required God…
The British natural theologians of the seventeenth, eighteenth, and nineteenth centuries, starting with Robert Boyle and John Ray (1627-1705) and culminating in the natural theology of William Paley (1743-1805), looked to biological systems for convincing evidence that a designer had acted in the physical world… For many [this] was the traditional Christian God, but for others it was a deistic God, who had created the world but played no ongoing role in governing it.
Note that this author, in a matter-of-fact way, makes a number of points that Thomists have emphasized when criticizing Paley and other defenders of the “design argument” – that the argument differs from arguments like Aquinas’s in assuming a “mechanical” conception of nature, that what is essential to this mechanical conception is an anti-Aristotelian view of formal causes and teleology as “externally imposed” rather than “immanent,” that this approach gives us at best a “deistic god” who need not play any “ongoing role” in governing the world, and that at worst it leads inadvertently to atheism. So, who is the author? Why, none other than ID theorist William A. Dembski, in his book The Design Revolution, at pp. 66-67. ID theorists who want to assimilate Paley and Aquinas might want to have a word with their friend Bill first, before complaining to us Thomists.
We’ll come back to Dembski. It is worth noting first, though – while we’re on the subject of ID – that in none of the passages from the Thomists cited above is Paley criticized on Darwinian grounds. None of these authors say “We’ve now got a perfectly good evolutionary explanation of biological phenomena of the kind Paley appeals to, so his defenders need to get with the times.” Indeed, as the alert reader will have noticed, Fr. Knox even avers that “the champions of natural selection [have not] managed to get rid of adaptation altogether.” Yet he still dismisses Paley’s argument as “feeble,” “deistic,” and not worthy to be counted even as a “modification” of any of the arguments he regards as the presupposition of “the whole traditional theology of Europe”! And at least the Neo-Scholastics among the authors cited above would by no means issue a blank check to Darwinian naturalists. While they are willing to allow evolutionary explanations a fairly wide scope, they insist that such explanations have limits, and that these limits are metaphysical and absolute, not empirical and evidential. They would agree, for instance, that there can in principle be no explanation of the origin of the human intellect in naturalistic terms, and thus no explanation in Darwinian terms, for reasons of the sort I’ve discussed many times. And as I’ve discussed in an earlier post, there are also metaphysical constraints that A-T insists would have to be met by any possible account of the origin of life, and they are not constraints any naturalist could accept.
The issues are complicated and A-T philosophers disagree over the details. The point is that the A-T critique of Paley and of ID theory simply has nothing essentially to do with Darwinism one way or the other. Some A-T critics of ID and of Paley have emphasized the compatibility of A-T and evolution and some have not, but that just isn’t what the debate is fundamentally about. Even if it turned out that there was no truth whatsoever to Darwinian or other evolutionary accounts of biological phenomena, this would not affect the A-T critique of Paley and ID theory in the least.
This point cannot be emphasized too greatly. ID defenders sometimes claim that Thomist criticism of ID and of Paley rests on too uncritical an acceptance of the empirical and conceptual claims of Darwinians. For instance, Logan Paul Gage makes this charge in a recent piece in Touchstone. I am one of the Thomists Gage criticizes, but it is hard to believe Gage has carefully read anything I’ve written on this topic. For one thing, my own criticisms of ID and of Paley have made little reference to Darwinism; that the A-T critique of ID has nothing essentially to do with either accepting or rejecting Darwinism is something I’ve emphasized consistently and repeatedly. For another thing, Gage’s specific comments on my own work show that he has entirely missed the point I have been making. For he tells us, as if it conflicted with my position, that “there’s certainly nothing anti-Thomistic in distinguishing between a generic argument for design and an argument for God’s existence—even if the former might provide evidence for the latter.”
I hear this sort of thing constantly, and it is – like the Darwinism red herring – getting very, very tiresome. “Gee whiz, Ed, what’s wrong with an argument for a designer, even if it is only a probabilistic argument and doesn’t tell us everything about the designer’s nature?” I don’t know why so many ID enthusiasts seem to have such difficulty understanding what they read. Sometimes I wonder whether dyslexia might be contagious, and that it is transmitted via Discovery Institute fund-raising letters. Really, how many times do I have to say it? At least one more time, it seems, so here goes: The Thomist’s problem with the arguments of Paley and ID theory is not – NOT (See that? It says “not”) – that they are merely probabilistic, or that they don’t get you all the way to the God of classical theism. There’s nothing wrong with that. The problem with these arguments is rather that they don’t get you even one millimeter toward the God of classical theism, and indeed they get you positively away from the God of classical theism.
This is the point Martin is making in the passage cited above when he says that Paley’s “designer” is really just the god of Deists and Freemasons and not the true God; the point Renard is making when he says that a mere “super-architect” is not its own “To Be” (i.e. its essence and existence are not identical) and thus is not God; the point Reith is making when he says that merely asking for an explanation of certain specific regularities will never get you outside the physical order of things to the metaphysical order, but merely to some as yet unknown super-intelligence within the physical order (and hence of necessity non-divine); the point Mercier is making when he says that merely “scientific” considerations have “no cogency” in an argument for theism apart from “metaphysical” considerations which alone can take us outside the realm of act and potency to that which is “pure Actuality”; the point Gilson is making when he says that the “watchmaker” or “craftsman” of “cheap apologetics” commits us to an objectionable “anthropomorphism”; and the point Owens is making when he says that only what is “self-necessary” and “immobile” could possibly be that which directs all things to their ends. (The reason is that anything less than what is Pure Actuality would have some potential or potency, and since potential is always potential for some end, we would need to appeal to yet some other intelligent cause which directs this potential to its end, and thus wouldn’t truly have arrived at a supreme intelligence. See Aquinas for the full story.)
It is a point I have made over and over and over again, though many of my critics refuse to address it. My objection to Paley and to ID theory has consistently been that, given:
(a) their eschewal, even if only “for the sake of argument,” of immanent formal and final causes and thus of the classical metaphysical apparatus associated with them (such as the act/potency distinction), and
(b) their univocal application of predicates both to God and to human designers (as opposed to “analogous” predication, in the Thomistic sense of the term),
these approaches lock us within the natural order and cannot in principle get us beyond it. In particular, they cannot in principle get us to a “designer” that is anything but one creature among others, even if a grand and remote one. In short, they get us to paganism, and thus away from classical theism. (Again, see the posts linked to above, especially this one, this one, and this one.) If you disagree with this claim, fine, but please, please stop pretending that the issue has anything to do with Darwinism, or anything to do with an unreasonable refusal to consider merely probabilistic arguments for God’s existence.
This brings us back to Dembski. For like other ID defenders, he sometimes insists – for example, at pp. 64-65 of The Design Revolution – that whereas “Paley’s business was natural theology” ID theory has “much more modest” ambitions in that it merely “seeks to identify signs of intelligence to generate scientific insights” and “attaches no significance to questions such as… whether the designer actually exists or what the attributes of that designer are.” Indeed, he even allows (at p. 188) that any “designer” ID theory points to could in principle be an extraterrestrial rather than God. So, it might seem that A-T objections to Paley are irrelevant to ID theory. In particular, it might seem that the ID theorist could say “Fine, so our methods don’t lead us to the God of classical theism any more than Paley’s do, but we weren’t trying to do that in the first place.”
Except that by pages 148-49 of the same book Dembski is telling us that:
The idea that nature is a closed system of natural causes and that natural causes provide a complete account of everything that occurs in nature is deeply entrenched in the West… The theory of intelligent design challenges… that misconception by pointing to phenomena in nature that nature is in principle incapable of accounting for strictly in terms of natural causes, namely, phenomena that exhibit specified complexity.
and immediately after floating the “extraterrestrial” hypothesis he immediately tells us that it would merely generate a regress, since any “embodied intelligence” would itself require explanation. So, according to Dembski, ID theory leads to a non-embodied designer outside the natural order. Moreover, Dembski tells us in his book Intelligent Design that ID theory is, among other things, “a way of understanding divine action” (p. 13) which shows that “God’s design is… accessible to scientific inquiry” (p. 17) and that “science and theology… provid[e] epistemic support for each other’s claims” (p. 18). But how exactly is all that supposed to differ from a design argument?
The answer is that it doesn’t. True, Dembski claims to have a method for detecting “design” that is better than Paley’s – that’s where all the stuff about “specified complexity” comes in – but that is irrelevant to the specific point at issue here, which is that however else it differs from Paley, ID theory shares with his design argument features (a) and (b) above, and is therefore, at least with respect to its theological significance, simply incompatible with Thomism.
As I have said many times, it is its eschewal of immanent final causality that makes ID theory “mechanistic” in the specific sense of “mechanism” that A-T philosophers object to; and as we saw here and here, Dembski himself essentially acknowledges that ID is “mechanistic” in that sense. (Those who want to reconcile ID and A-T should at least try to understand what A-T philosophers mean when they attribute an objectionably “mechanistic” view of nature to ID theory – as Anne Barbeau Gardiner, who criticized my position in a recent piece, shows no evidence whatsoever of doing.)
At this point, of course, ID defenders will remind us that “mechanism” is adopted by ID only in a “for the sake of argument” way. And I will remind them that this is irrelevant to the point at issue. Suppose that, investigating a crime, you say: “Let’s suppose just for purposes of our investigation that the murderer was someone who would have been captured on this surveillance camera.” Then you have by virtue of this constraint necessarily limited yourself to potential suspects in the vicinity of the camera, and will be unable to identify the murderer if so happens that he was not in the vicinity. Similarly, if you start with a conception of natural substances as “artifacts” of a certain kind – as you are bound to do if you reject immanent formal and final causes, for reasons I’ve discussed here and here – then you are going to conceive of the “designer’s” activity on the model of a human tinkerer, a cosmic Thomas Edison who does something comparable to taking pre-existing bits of matter and rearranging them to make a kind of machine. And that just isn’t the way God creates, either for A-T or for classical theism more generally. It is the way a pagan demiurge “creates” things; that is to say, it isn’t true creation at all (in the classical theist sense) but merely one super-intelligent and super-powerful but ultimately merely natural entity generating another, less intelligent and powerful one.
Saying “But I’m only supposing this for the sake of argument” doesn’t help in the least. That’s like saying “But I’m only supposing for the sake of argument that the murderer must have shown up on this surveillance camera.” So long as you make that supposition – whether for the sake of argument or otherwise is irrelevant – you will never consider suspects who were not in the vicinity of the camera, and so your investigation will never get you even one inch closer to the actual murderer if indeed he was someone who was out of camera range. Similarly, so long as you insist (for whatever reason) on treating natural substances as if they were a kind of artifact, and on predicating attributes of both the world’s “designer” and of human designers in a univocal way, you will never (from an A-T point of view, anyway) get even one inch closer to the God of classical theism, because you will necessarily be describing the “designer” in a way that not merely falls short of, but is positively inconsistent with, classical theism. (Again, interested readers are referred to my earlier posts on this subject for a fuller discussion.)
In summary, then:
1. That Aquinas’s position is incompatible with Paley-style design arguments (and thus, by implication, with ID theory) is a long-standing and widely shared judgment within the Thomistic tradition, and follows from Thomism’s basic metaphysical and theological commitments.
2. The dispute between Thomism on the one hand and Paley (and ID theory) on the other has nothing essentially to do one way or the other with Darwinism. That is a separate issue. Whether you accept Darwinism or reject it, the Thomistic objection to Paley and to ID theory stands.
3. The dispute also has nothing essentially to do with whether one prefers demonstrative arguments to probabilistic ones, or with the question of whether this or that argument tells you everything about God’s nature. It is true that the Fifth Way is intended to be a metaphysical demonstration and (at least when the basic thrust of the argument is followed out consistently) leads us to a conception of God as Pure Actuality (from which the other divine attributes can be deduced); while design arguments are typically merely probabilistic, and do not tell us much about God’s nature. But that by itself is not a problem, and it is not the reason why Thomists object to Paley and to ID theory.
4. The dispute also has nothing to do with whether or not ID theorists might have important things to say about how to detect design within the natural order, or whether they’ve made significant criticisms of this or that Darwinian account of this or that biological phenomenon. That is also a separate issue. A Thomist may or may not regard ID as bad science. The point I am making here is that ID is, from a Thomistic point of view, bad philosophy and bad theology.
It seems to me that many of those who take umbrage at Thomist criticism of Paley and of ID unthinkingly treat all such criticism as if it were a sell-out to secularists and loudmouth Darwinists like Richard Dawkins and Jerry Coyne. But the enemy of your enemy is not always your friend. And ID theory is not the friend of Thomism. It is the friend of the 17th century modernist philosophy and theology that unseated Thomism and Scholastic philosophy in general, just one more riff on the long parade of philosophical error that began with Descartes, Locke, and Co. and continues to this day. Those who want to marry A-T and ID should worry less about the “culture wars” and more about philosophical and theological rigor and coherence – the only sure way to win the “culture wars” in the long run in any case. They should also heed St. Thomas’s warning not to “bring forward reasons [for their convictions] that are not cogent” which merely “give occasion to unbelievers to laugh” (ST I.46.2).