As we have mentioned in many previous posts (see here, for example), we agree with legal philosopher John Finnis that one of the goals of law is to solve coordination problems and promote human cooperation. But one of the main weaknesses with or blind spots in Finnis’s work is that he doesn’t bother to address the following key question: how can law and cooperation actually get started? Simply put, there is a chicken-and-egg problem here: we need law to punish defectors and promote cooperation, but we need cooperation to have a legal system capable of enforcing contracts and punishing defectors. In a word, cooperation is hard.
For his part, mathematician and game theorist Karl Sigmund describes several solutions to this fundamental puzzle in this fascinating conversation. (The link includes both video and audio of the conversation, along with a complete transcript.) Among other things, Professor Sigmund describes two standard methods for promoting cooperation among two individuals in the absence of law: Humean reciprocity (“tit for tat”) in iterated or repeat interactions and reputation mechanisms (“indirect reciprocity”) in the absence of repeat interactions:
Cooperation is so obviously the secret to success of the human species, and one of the reasons why is reciprocation—tit for tat—and other strategies for sustaining cooperation in a repeated interaction between two players. If you do not have these repeated interactions, you have to look for different mechanisms to support cooperation. One of them would be indirect reciprocity. This works even if the two players meet only once provided that they can have some information about each other. In other words, it works if the players have a reputation that can be assessed by the other players. Then it’s quite obvious that you are inclined to trust someone with a good reputation and to collaborate with them versus someone who has a bad reputation.
What about when n is greater than two? In short, what about groups? In this case, one solution is for members of the group to set up institutions and enforcement mechanisms ahead of time to punish defectors:
There is a much more stable situation that occurs when the players beforehand set up a contract, or hire a sheriff, or make a kind of institution whose aim it is to punish those who eventually will free ride [i.e. defect]. This is a different thing. You set up a kind of police force beforehand. Nowadays, this happens all the time. Whenever you make a collaborative enterprise, you go first of all to a lawyer, you set up some contracts, and if you break these contracts, you are punished. But the interesting thing is that this happens also in situations that are much more elementary.
Professor Sigmund then devotes the remainder of his talk explaining how corruption can undermine cooperation and the rule of law. (For a technical summary and analysis of cooperation, check out Martin Nowak’s excellent paper: “Five rules for the evolution of cooperation.” Here is an ungated version of Nowak’s paper.) For my part, one of the things I like the most about game theory models is that they make difficult problems tractable by simplifying the world around us; for example, game theory reduces choices and actions to two ideal types: cooperate or defect. But broadly speaking, game theory approaches to law and cooperation suffer from several deficiencies. In particular, I will identify and discuss two big problems with such models in my next post.