Even before John Derbyshire put up his post on “Biology of Behavior” earlier today, I had received a number of thoughtful e-mails from readers telling me about the evolutionary advantage of systems of morality. And I have no interest in denying this: Overall, cultures that cultivate altruism and moral behavior may well prosper more than cultures that do not. As someone who is an unapologetic believer in evolution, and in the fact that that there is a principle of natural selection at work—and someone who is simultaneously a believer in the existence of a Divine Designer who is the source and principle and creator of that system—I see no reason why ordinary ethical systems shouldn’t confer an advantage on cultures that have them. What intrigues me, though—and this points away from the purely materialistic system to something uncanny, something for which I use the traditional term “God”–is the passion for justice, the sense of right and wrong. I think of the Latin motto “Fiat justitia, ruat caelum”—”let justice be done, though the heavens fall.” Let’s say—to take a purely hypothetical example–that I know a certain immoral and unconstitutional measure would significantly improve my country’s chance of defeating terrorists who threaten its existence. And yet I say: “NO! I refuse to do that, even though refusing to do it endangers myself and my country, simply because I believe it to be wrong.” This moral sense clearly violates the imperative of self-preservation. The pure materialists might say that it is merely an evolutionary blind alley, and those who join me in pursuing it will be rewarded with extinction. I certainly cannot prove them wrong. But until that extinction comes, I can’t deny the existence of this sense. It’s something that doesn’t appear to fit; it doesn’t appear to be “helpful” to me in the struggle for survival; eppur si muove.