Richard Dawkins maintains in The God Delusion that Aquinas tries, but fails, to prove the existence of God through the argument from design. But this is not what Aquinas was trying to do. The background here is all important. In the University of Paris Aquinas was being accused of atheism, ironically enough, because of his use of Aristotle, who thought that the universe had no beginning and no creator.
In the five ways Aquinas was not trying to prove the existence of God at all, but was showing that an acceptance of Aristotle is no bar to belief in God. This is why he ends each argument not with "QED God" but "And this is what all men call God". Aquinas does not think God exists. He thinks he is existence. Aquinas does not think, as Paley did, that God is outside the world but within it. "God dwells in the world and that innermostly", and this is why natural things are so beautiful and sometimes awesomely sublime. The relation of the world to God is not that of a watch to its maker. It is more like that of a picture to the artist who painted it. We do not say that Picasso is his picture. But nor do we think that he manufactured it. It is full of his style, his personality, the very presence of his creative being. There is a sense in which Picasso both is and is not his picture. An even closer analogy to Aquinas's thinking, perhaps, would be the relation of myself to my body.
Aquinas would have had no problem with Hawking's contention that the Big Bang didn't need somebody to light its fuse but can be explained mathematically. Nor with an infinity of universes. Indeed, the idea that the Big Bang was the other side of the annihilation of a previous universe in a black hole neatly solves a dilemma. Aristotle thinks, on the one hand, that a series of efficient causes must have a beginning but, coming at it from another angle, also thinks that the universe could not have had a beginning because there was nothing outside it to begin it. Still less would Aquinas have been dismayed by Darwin's discovery that species have a natural origin. He would have loved Darwin just as he loved Aristotle. The idea of the glorious unfolding of life amidst circumstances of accidental hazard would have fascinated him. Indeed, the gradual revelation of the fullness of being in nature amidst the hazards of the environment is paralleled by the gradual revelation of God in scripture amidst the hazards of history. It would have confirmed everything that Aquinas thought about the relation of the natural to the supernatural. Grace does not undo nature, he wrote, but fulfils it.
Most of all, though, Aquinas would have been entranced by the idea of genes. If ever there were an Aristotle-friendly idea this is it. Genes illustrate both of Aristotle's two fundamental principles. One is that immaterial forms do not exist in some nebulous heaven, as Plato thought, but are embedded in material things themselves. This is exactly what we find in genes. The essence of genes is that they encode information. But you can't encode bits of stuff, only ideas. At the heart of the material we find the immaterial. Aristotle's other big idea is act and potency. Everything is potentially the something else that it is already ordained to be. Bronze becomes statues, not primroses, live humans become dead ones, not alarm clocks. The whole essence of genes is that they are potentially the actual things that they already in some essential sense are. Genes are potentially phenotypes and phenotypes are activated genes.
Aquinas never employs the argument from design. As an Aristotelian he disagreed with it profoundly. The analogy he uses is that of the archer to the arrow he fires, and Dawkins' comment that Aquinas would have done much better with a heat-seeking missile betrays how far Dawkins has totally misunderstood Aquinas. Aquinas's question was not "how is it that such complicated things have come to be moving round in the world" but "how is it that unintelligent things can behave so intelligently?"
Genes, intelligence, and purpose
This question reaches its sharpest apex in genes. How is it that tiny scraps of organic matter can display such powers of determination and agency? So purposeful do genes appear to be that even Dawkins is constrained to talk in the language of purpose, although he hastens to assure us that when he says purposeful what he really means is purposeless (The Selfish Gene p. 196). Just as Darwin did, neo-Darwinians often talk about nature as if it were God. "This is perhaps one reason why natural selection has taken so much trouble to ensure that we recognize human faces" (Helena Cronin), "one such gene is bad enough but evolution could then conjure up another'(Mark Ridley), "the depth of insight to be discovered in one of Mother Nature's creations" (Daniel Dennett), as if the problems of agency provoked by these metaphors could be dispersed by the scare quotes with which they are so frequently garnished. Although, I do have to say, Dennett does have a stab of doubt on page 185 of Darwin's Dangerous Idea, " ...we can see the intelligence of Mother Nature (or is it merely apparent intelligence) as a non-miraculous and non-mysterious – and hence all the more wonderful – feature of this self-creating thing", and even goes so far on page 133 to refer whimsically to natural selection as "perhaps jocularly personified as Mother Nature". I would love to see the serious version. Dennett – thirty one references to Mother Nature in the index - makes medieval herbalists sound like Francis Crick.
Yet how Aquinas would have agreed with that "non-miraculous" and Dennett's "self-creating thing", though not with the non-mysterious, for if there is one thing science tells us it is that reality continually astonishes us even beyond our wildest imaginings.. How right Dawkins and Dennett are to reject pseudo-religious explanations in favour of the real thing But they do not penetrate into reality far enough. Either you have to think that unintelligent genes behave in the way that they do because they are expressions of a profounder intelligence, or you have to think that they unintelligibly and mechanically just do what they do, but we, committed to intelligence, can only talk about them as if they were intelligent. They do not build survival machines for themselves but 'build survival machines for themselves". Personally, I find the idea that intelligent means unintelligent or that purposeful means purposeless less than intellectually compelling. How Aquinas would have adored genetic biology
In the end, why do I think that Aquinas is right and Dawkins is wrong? Partly because the world is so beautiful. Natural selection explains the origin of species most satisfyingly. But it doesn't explain why they are so beautiful. And what about those uncountable millions thoughout the ages who have claimed an intensely meaningful personal relationship with the ground of existence? This experience has been corroborated so many times, you would have thought that people who swear by peer review would have paid heed. If, as seems to be the case, it is impossible to talk about mother nature except in terms of a personal creative force, then perhaps, if language is to mean anything at all, the difference between Dawkins and Aquinas is not really very great.