Well, I guess Dembski would know what ID theory is really committed to, if anyone does. The trouble is that even he doesn’t seem to know, because despite these disavowals of mechanism, the rest of the book is peppered with assertions that presuppose the truth of a mechanistic conception of nature. Or perhaps Dembski simply doesn’t understand what A-T theorists mean by “mechanism.” Either way, there can be no doubt that ID theory, as Dembski conceives of it, is mechanistic through and through in the sense of “mechanism” that A-T rejects.
Take Dembski’s discussion of Aristotle at pp. 132-3 of The Design Revolution (which, if you don’t have a copy of the book, you can read for yourself here via Google Books). Dembski here identifies “design” with what Aristotle called techne or “art.” As Dembski correctly says, “the essential idea behind these terms is that information is conferred on an object from outside the object and that the material constituting the object, apart from that outside information, does not have the power to assume the form it does. For instance, raw pieces of wood do not by themselves have the power to form a ship.” This contrasts with what Aristotle called “nature,” which (to quote Dembski quoting Aristotle) “is a principle in the thing itself.” For example (again to quote Dembski’s own exposition of Aristotle), “the acorn assumes the shape it does through powers internal to it: the acorn is a seed programmed to produce an oak tree” – in contrast to the way the “ship assumes the shape it does through powers external to it,” via a “designing intelligence” which “imposes” this form on it from outside.
Now, having made this distinction, Dembski goes on explicitly to acknowledge that just as “the art of shipbuilding is not in the wood that constitutes the ship” and “the art of making statues is not in the stone out of which statues are made,” “so too, the theory of intelligent design contends that the art of building life is not in the physical stuff that constitutes life but requires a designer” (emphasis added). And there you have it: Living things are for ID theory to be modeled on ships and statues, the products of techne or “art,” whose characteristic “information” is not “internal” to them but must be “imposed” from “outside.” And that just is what A-T philosophers mean by a “mechanistic” conception of life.
Remember, this does not mean that A-T denies that living things are created by God; far from it. The point is rather that for A-T, the way God creates a natural substance is not to be understood on the model of a shipbuilder or sculptor who takes pre-existing bits of matter and rearranges them to serve an end they have no tendency otherwise to serve. Nor is the point affected in the least if we imagine that when the pre-existing bits of matter are created this external order is imposed immediately; temporal considerations are irrelevant. For A-T, a natural substance is a composite of “prime matter” (matter having no form at all) and substantial form, rather than a piece of “second matter” (matter already having some substantial form or other) which has acquired some accidental form from outside it. And a natural substance’s causal tendencies, including biological functions in the case of living things, are inherent to it, a reflection of its essence or nature; it simply could not possibly exist as the kind of thing it is in the first place if it did not have those tendencies, and thus it would have them even if (per impossibile) it had not been created by God. The way God creates living things, then, is the same way He creates everything else, viz. by conjoining an essence to an act of existence, which in the case of material things (including plants and animals) entails conjoining a certain kind of prime matter/substantial form composite to an act of existence.
Remember too that none of this has anything to do with Darwinism, the debate over which is a separate matter. Perhaps the biological world God creates works according to Darwinian principles; and perhaps not. Either way, the question will not be resolved by weighing against Darwinian naturalism a “design inference” to some artificer who adds some extra “information” to the natural world in the way a shipbuilder gives structure to wood in order to make a ship.
As I have explained many times and in many places where this subject has come up, the core to the mechanistic revolution of the early modern philosophers was the rejection of Aristotelian formal and final causes. Other elements of mechanism (such as the notion that all efficient causes work according to a crude push-pull model) fell away over the centuries, but this essentially negative vision – that however the natural world works, it does not involve either anything like substantial forms (which are irreducible to the sum of a natural substance’s parts, or even to the sum of its parts together with an externally imposed or observer-relative function) or anything like final causality (the “directedness toward an end” that the Scholastics claimed was manifest even in basic causal regularities). In other ways too Dembski makes it clear that he accepts this mechanistic approach to the world.
For example, at p. 140 of The Design Revolution, Dembski flatly asserts that “lawlike [regularities] of nature” such as “water’s propensity to freeze below a certain temperature” are “as readily deemed brute facts of nature as artifacts of design” and thus “can never decisively implicate design”; only “specified complexity” can do that. But for A-T, such regularities are paradigm examples of final causality ; that some A is an efficient cause of some effect or range of effects B is for A-T unintelligible unless we suppose that generating B is the final cause or end at which A is naturally directed. Even the simplest causal regularities thus suffice “decisively” to show that there must be a supreme ordering intelligence keeping efficient causes directed toward their ends from instant to instant, at least if Aquinas’s Fifth Way is successful. Complexity (“specified” or otherwise) has nothing whatsoever to do with it. (I’ve addressed this issue many times in various blog posts, and see Aquinas and The Last Superstition for the full story.) That Dembski considers it at least in principle possible that such causal regularities are “brute facts” which can never decisively implicate design suffices to show that his conception of causality is mechanistic in the relevant sense, viz. one which eschews inherent final causality.
More could be said, but that suffices to make the point. It is worth adding, though, that the ambiguity in question here – denying mechanism in some places while affirming it in others – has parallels elsewhere in Dembski’s work. For example, he uses the term “information” (in The Design Revolution and elsewhere) in several different senses and freely slides from one to another without always making it clear which one is supposed to be doing the work in a given argument. In some places he insists that the “designer” that ID posits could in theory itself be something in the natural order, such as an extraterrestrial, so that there is no truth to the charge that ID has an essentially theological agenda. But elsewhere he insists that “specified complexity” cannot be given a naturalistic explanation, and even allows that positing a designer who is part of the natural order would only initiate an explanatory regress – which would imply that a genuine explanation would require an appeal to the supernatural. His main arguments all evince an unmistakable realist thrust, and yet in response to a particular objection he suggests that ID theory is perfectly compatible with a non-realist philosophy of science (though it does not seem to occur to him that his Darwinian opponents could make exactly the same move in response to some of his criticisms of them). And so forth.
In short, Dembski seems intent on sidestepping potential objections by making ID as flexible as possible, so long as the word “design” is preserved. This explains why some readers assume that there is nothing in ID that is incompatible with A-T metaphysics. But imprecision and incoherence are not the same as compatibility. And amidst all the ambiguity, Dembski’s commitment to an essentially mechanistic conception of nature (as A-T understands “mechanistic”) stands out as one of the more consistent themes of his work.