Descent of Man, Darwin notes: Human morality Mankind is a social animal, and has inherited its moral traits through the evolution of morality. As Darwin notes, the moral difference between mankind and animals, however, is "certainly one of degree and not of kind." Emotions such as remorse, regret or shame one may feel, stem from human's incessant reflection on past experiences and preoccupation with the judgement of others. See also Ethics Evolution of empathy Naturalism (philosophy) References Further reading Wong, David, 2006, Natural Moralities, A Defense of Pluralistic Relativism, Oxford University Press, Morality Altruism Human evolution Evolutionary psychology