A Paradox of Rationality and Cooperation
A walrus and a carpenter were walking down a beach on a sunny winter’s day. The sand was still frosty in places, but the frost was melting in the sun. The water was calm, and waves lapped gently on the beach. “Isn’t it beautiful?” said the walrus, after they had been walking along in silence for a while. “Yes, it is,” said the carpenter. “I’m glad you suggested this walk.” “Well, I wanted to share this beautiful day with you,” said the walrus. “And I have a paradox to share with you as well.” “Oh no!” said the carpenter, laughing, “This was a trap!” “Well, maybe a little,” admitted the walrus, “but I really think you’ll enjoy this paradox.” “Okay,” said the carpenter. “Hit me with it.” “You know what the prisoner’s dilemma is, don’t you?” “Yes, it’s an important concept in game theory. It’s an example of a game that isn’t zero sum.” “Right. We can forget about the original idea of two prisoners, and just define it as a simple game with two possible moves: c