You Can't Get Ought From Is
David Hume famously described the Is/Ought problem: there is no logical means of deriving moral values from statements of fact. Well before there was any evolutionary theory of morality, he recognized that our will is a "slave of the passions". Our motivations do not derive from reason alone. Through instinct, we make judgments about what is right and wrong. Through our sense of pride, humility, love and hate, we are motivated, and we experience social approval or disapproval as a result of our actions.