I strongly agree with what I take to be Arnhart's basic claims: that Aristotle's teleological biology is plausible in the light of what we now think about good scientific practice, and that it provides a kind of basis or vocabulary for moral and practical deliberation that is lacking in nonteleological or reductionist biology. Arnhart's defense of these claims is important both because he suggests a more expansive notion of what counts as biological science and because he in effect challenges Macintyre's (1981) claim that Aristotle's biology is “metaphysical” and so cannot serve as a basis for theorizing about moral and political matters. Arnhart makes his case well, and I was especially instructed by his discussion of Sacks' work as an example of a teleological vocabulary applied to moral and psychiatric questions.