Some biologists argue that morality grew out of behavioral rules shaped by evolution. They see social behaviors displayed by some primates as the precursors of human morality. They cite examples such as rhesus monkeys which, when given a chance to get food by pulling a chain that delivers a shock to another monkey, have been known to starve themselves for a considerable time.<ref> "Primates and Philosophers" by Frans de Waal</ref> | Some biologists argue that morality grew out of behavioral rules shaped by evolution. They see social behaviors displayed by some primates as the precursors of human morality. They cite examples such as rhesus monkeys which, when given a chance to get food by pulling a chain that delivers a shock to another monkey, have been known to starve themselves for a considerable time.<ref> "Primates and Philosophers" by Frans de Waal</ref> |