the assumption of selfishness seems naive. Social interactions require collaboration and cooperation with others. Selfishness and egotism are not traits associated with the ability to interact fruitfully with other people. Cooperating and caring about others is not, in that sense, “irrational”.

The Law of Talion, one of the oldest recorded laws dating back to Babylonian times, states that retaliation should be in proportion to the offence: "an eye for an eye." The reciprocity of the Law of Talion can be found in the oldest known code of law, the Code of Hammurabi from 1750 BCE.