Evolutionary Ethics

American evolutionary biologist Robert Trivers believes that moral emotions are based on the principle of reciprocal altruism. His theory posits the different emotions have different reciprocal effects. Sympathy prompts a person to offer the first favor, particularly to someone in need for whom the help would go the furthest. Anger protects a person against cheaters who accept a favor without reciprocating, by making him want to punish the ingrate or sever the relationship. Gratitude impels a beneficiary to reward those who helped him in the past. Finally, guilt prompts a cheater who is in danger of being found out, by making them want to repair the relationship by redressing the misdeed. As well, guilty feelings encourage a cheater who has been caught to advertise or promise that he will behave better in the future.

To understand how evolution promotes ethics, we must consider the perspective not of the individual but of a gene. In particular, when organisms act altruistically, against their individual interests (in the sense of health, safety or personal reproduction) to help related organisms reproduce, can be explained as gene sets "helping" copies of themselves (or sequences with the same phenotypic effect) in other bodies to replicate. Interestingly, the "selfish" actions of genes lead to unselfish actions by organisms.