Our world is not an optimal place, fine tuned by omnipotent forces of selection. It is a quirky mass of imperfections, working well enough (often adm… - Stephen Jay Gould

But here I stop—short of any deterministic speculation that attributes specific behaviors to the possession of specific altruist or opportunist genes. Our genetic makeup permits a wide range of behaviors—from Ebenezer Scrooge before to Ebenezer Scrooge after. I do not believe that the miser hoards through opportunist genes or that the philanthropist gives because nature endowed him with more than the normal complement of altruist genes. Upbringing, culture, class, status, and all the intangibles that we call “free will,” determine how we restrict our behaviors from the wide spectrum—extreme altruism to extreme selfishness—that our genes permit.

[S]cientists are not robotic inducing machines that infer structures of explanation only from regularities observed in natural phenomena (assuming, as I doubt, that such a style of reasoning could ever achieve success in principle). Scientists are human beings, immersed in culture, and struggling with all the curious tools of inference that mind permits […]. Culture can potentiate as well as constrain—as Darwin's translation of Adam Smith's laissez-faire economic models into biology as the theory of natural selection. In any case, objective minds do not exist outside culture, so we must make the best of our ineluctable embedding.

No one doubts that biological universals exist. We must sleep, eat, and grow older, and we are not about to give up procreation; almost all our social institutions are influenced by these imperatives.