Evolutionary Psychology and Darwinism as an Idée Fixe

We need to remind ourselves from time to time that Darwinism is more than a scientific idea, and more than the seed of a social philosophy or worldview. It's also a prime example of the kind of rigid thinking -- the idée fixe or fixed idea -- that bedevils seemingly unrelated fields having to do with diet, therapy, advice, and self-help, with results that are sometimes comic, sometimes more unfortunate than that.

A fixed idea is one that, for the believer, applies everywhere and to...