The Prison of War & Peace

A few days ago I began a survey of Martin Nowak's treatment of modern game theory in his book Evolutionary Dynamics. Today I'm going to hit the Prisoner's Dilemma. Roughly, this scenario is one where two individuals are isolated, and if they both keep their mouths shut (cooperate) they get off, but, if one rats the other out while the other keeps silent, the silent partner is screwed while the snitch gets off. If both of them rat the other out they get a prison sentence, but a lighter one than if they had kept silent while the other ratted them out. In other words: ratting the other person out is the "rational" option. So, the question is, why don't we see a war of all against all in the world around us? That is what Nowak addresses in a whole chapter, and his exploration and treatment is highly ambitious, ...