Are human beings naturally cooperative or selfish? Can people thrive without government law? Paul Robinson of the University of Pennsylvania and author of Pirates, Prisoners and Lepers talks with EconTalk host Russ Roberts the ideas in his book. Robinson argues that without government sanctions or legislation, there is an evolutionary drive to cooperate even in life-and-death situations. In such situations private punishment and norms play a crucial role in sustaining cooperative solutions. The last part of the conversation deals with the criminal justice system and how attitudes toward the system affect society-wide cooperation and crime.