Larry Arnhart has a good post today, providing another example of why I think Aquinas and Darwin would have gotten along quite well:
Under the influence of Aristotle’s biology, Thomas concluded that, although only human beings act from “free” judgment, other animals act from “estimative” judgment about what will satisfy their desires. Thus all animals have a natural capacity for practical judgment that shows a certain “participation in prudence and reason” and a certain “likeness of moral good” (ST, I, q. 83, a. 1; q. 96, a. 1; I-II, q. 11, a. 2; q. 24, a. 4; q. 40, a. 3). The influence of this biological psychology on the Thomistic understanding of natural law is evident in the account of marriage in the Supplement to the Summa Theologica (q. 41, a. 1; q. 54, a. 3; q. 65, a. 1-3; q. 67, a. 1).