I am not going to quibble with Miller’s claim that there is a distinction between purpose and function, for I do not think it is relevant to my case against Dawkins. After all, in order for Dawkins to assess the morality of another’s actions he must not only know how the parts of a human being function and for what end (for example, the brain helps facilitate the acquisition of knowledge), he must also account for cases in which proper function is employed for the wrong end.
So, in the case of Kurt Wise, what troubles Dawkins is not that Wise did not use his brain to acquire knowledge, for no one including Dawkins is calling into question Wise’s intelligence and depth of learning. Rather, Dawkins does not think that Wise acted virtuously in light of his intelligence, depth of learning, and knowledge. But such a judgment is not conditioned exclusively upon the parts of a human being and their proper function. It is conditioned upon both what it means to be a human being as a whole and how as a human being one ought to employ one’s constituent parts for a virtuous end. This is why I wrote in my original entry that "the notion of a ‘proper function’ . . . coupled with [emphasis added] the observation that certain perfections grounded in basic capacities have been impermissibly obstructed from maturing, is assumed in the very judgment Dawkins makes."
Miller is indeed correct that Aristotle’s view does not entail God’s existence, since living organisms and their intrinsic purposes informed by their natures may just be brute facts of the universe for which no explanation is required. But Dawkins can’t embrace that position, for he does indeed offer an explanation, one that denies that living organisms have intrinsic purposes and real natures. According to Dawkins, the "natures" that we ascribe to living beings arise out of the vast eons of time in which natural selection cooperates with random genetic mutations and perhaps other evolutionary forces. Consequently, living beings do not possess the stable realist natures that Aristotle believed exist. Rather, for Dawkins, the natures we ascribe to living beings are merely names (or "nominal essences") that are shorthand ways to label beings that have roughly similar characteristics. So we may say that resulting from "human nature" are those practices, habits, and institutions of the tool-using, language-employing, featherless bipeds that have DNA similar to our own. But this "human nature" tells us nothing normative. It merely describes what is statistically ordinary and generally species preserving.
Consequently, I disagree with Miller that Dawkins may appropriate Aristotle in order to ward off the sort of criticism I have offered. In Aristotle’s universe, living organisms are substances consisting of form and matter, with form imparting to the organism an essential nature that provides to it intrinsic purposes that have normative content. For Dawkins and other like-minded scholars, immaterial things like essences, natures, not to mention minds and souls, are absent from the furniture of the universe. Thus, the normative insights that a person may acquire by acquaintance with these things is not a resource into which Dawkins may tap without abandoning his metaphysics altogether. So, if Dawkins were to embrace Aristotle’s understanding, he would no longer be an atheistic materialist. In fact, he would be only a sliver away from the Kingdom of God, which is miles away from where he is now.