Punishment and cooperation: the "old" theory

The so-called problem of the spontaneous cooperation has been substantially resolved through a mix of biology and economics. All the elements of the solution had been discovered by 1980s, yet they went somehow unnoticed. This "old" solution is the subject of this review. Its most relevant feature was the discovery that the adoption of punishment as an equilibrium-enforcing device makes a cooperative solution in a repeated prisoner's dilemma possible. This opened the way to a biological (or anthropological) explanation otherwise logically inconsistent.