Abstract: This chapter presents an overview of the book. It argues that the metaphysical approach to ethics is a failure and that the time has come to take a scientific view of morality. A social contract is taken to be the set of common understandings that allow the citizens of a society to coordinate. Such social contracts are seen as the product of biological and cultural evolution. To survive, a social contract must therefore be an equilibrium in the repeated game of life played by a society. Since the folk theorem of repeated game theory says that there are large numbers of such equilibria, fairness norms then become explicable as an equilibrium selection device that selects one of the many efficient equilibria of a society's game of life. It is suggested that the deep structure of such fairness norms is captured by John Rawls' notion of the original position, and is therefore universal in the human species. On the other hand, the standard of interpersonal comparison needed as an input to the original position is culturally determined.

Keywords: evolutionary ethics, sociobiology, social darwinism, social contract, game theory, Nash equilibrium, reciprocal altruism, cooperation, fairness norms, original position,