In my experience in dealing with anti-evolutionists, the fundamental motivation for dismissing evolution is not its adverse implications for religion itself (real or imagined, depending on your view), but the sense (definitely imagined) that accepting evolution subverts any basis for morality. One can go around and around with an anti-evolutionist only to discover in the end that he or she is really arguing from a moral perspective: “A naturalistic approach cannot show why it is absolutely wrong to kill someone, only divine moral laws can, thus evolution is unacceptable and hence incorrect.”
In this regard, it was with much interest that I read the piece by Steven Pinker in the New York Times on The Moral Instinct.
Now, I am not a major advocate of evolutionary psychology. Many of the “just-so stories” that come out of that circle make me either roll my eyes or cringe, depending on the usually overblown ratio of strength-of-claim to quantity-of-data. On the other hand, I would not argue that the human brain and the behaviours it exhibits are somehow exempt from the evolutionary processes that apply to every other organ in every other living species. However, that is not to say that all behaviours are adaptive — far from it. I suspect that some behaviours are (or were) adaptive, and some are not and never were.
Speaking specifically of innate human behaviours that are (or were) adaptive, I prefer to think of them as a series of “rules” or “guidelines” that are supplemented by details from culture. Nature via nurture. Language is a good example, and one that I use with students. The ability to learn a language is innate. Which language one learns is cultural. These are inseparable.
I have long thought that morality is rather similar. There is an innate moral compass that all normal humans possess (e.g., “the golden rule”, known to biologists as the basis of reciprocal altruism), but many of the specifics of what constitutes “good” versus “bad” are filled in by culture. Pinker takes a similar view, although he (I think correctly) distinguishes between societal conventions and moral principles, the former of which are especially culturally malleable. He also notes five basic themes that comprise the moral sense: harm, fairness, community (or group loyalty), authority, and purity (see also Haidt 2007). The proportions and expressions of these may vary among cultures, but they are universally identifiable in human beings. I quite like this formulation as a useful way to think about the differences and unities in moral judgments among people.
Finally, and perhaps most importantly, Pinker points out that studying and even explaining morality does not destroy it: if anything, it may help us to behave morally in a more effective way by adding some rationality to the equation.
The article is excellent, and I recommend it very highly.