Some animals are surprisingly sensitive to the plight of others. Chimpanzees, who cannot swim, have drowned in zoo moats trying to save others. Given the chance to get food by pulling a chain that would also deliver an electric shock to a companion, rhesus monkeys will starve themselves for several days.
Biologists argue that these and other social behaviors are the precursors of human morality. They further believe that if morality grew out of behavioral rules shaped by evolution, it is for biologists, not philosophers or theologians, to say what these rules are.
Moral philosophers do not take very seriously the biologists’ bid to annex their subject, but they find much of interest in what the biologists say and have started an academic conversation with them.
The original call to battle was sounded by the biologist Edward O. Wilson more than 30 years ago, when he suggested in his 1975 book “Sociobiology” that “the time has come for ethics to be removed temporarily from the hands of the philosophers and biologicized.” He may have jumped the gun about the time having come, but in the intervening decades biologists have made considerable progress.
Last year Marc Hauser, an evolutionary biologist at Harvard, proposed in his book “Moral Minds” that the brain has a genetically shaped mechanism for acquiring moral rules, a universal moral grammar similar to the neural machinery for learning language. In another recent book, “Primates and Philosophers,” the primatologist Frans de Waal defends against philosopher critics his view that the roots of morality can be seen in the social behavior of monkeys and apes.