At the American Enterprise Institute’s conference, the tension between the proponents of intelligent design and of evolution was occasionally on display. When Mr. Derbyshire described himself as a “lapsed Anglican,” which he compared to “falling out of a first-floor window,” Mr. Gilder piped up, “Did you fall on your head?”

Mr. West agreed that “conservatives who are discomfited by the continuing debate over Darwin’s theory need to understand that it is not about to go away”; that it “fundamentally challenges the traditional Western understanding of human nature and the universe.”