For example: we can compare how ethical traditions do in Prisoner’s Dilemmas against the game’s best strategy, called Tit-For-Tat, which is an “evolutionarily stable strategy.” As Tomas Sedlacek asks: What would Christians do? Or practitioners of any religious or secularly sourced Golden Rule? The results are clear: Rationalists do worse than the Golden Ruled. And Jewish preferences beat Christian ethics. So-called rationalists, dominated by some dire logic, produce no cooperation and low productivity. Two Golden Ruled players cooperate, thus beating rationalists. But New Testament turning-the-other-cheek is exploitable (as Machiavelli and Nietzsche complained). Old Testament eye-for-an-eye comes closer to Tit-For-Tat, if forgiveness follows (which might be divine, but is also evolutionarily adaptive). But punishment sufficient to ensure that cheating doesn’t pay must also prevent escalating revenge. Hunter gatherers avoid such feuds by delegating the severest punishment to close male kin. A “Golden Punishment Rule,” that mimics Tit-For-Tat, enables cooperation by sustainably preventing exploitation. Similar logic likely applies beyond Prisoner’s Dilemma. - blogs.scientificamerican.com