The Prisoner's Dilemma

The "prisoner's dilemma" comes up frequently in books on evolutionary psychology and similar topics.  (See pp. 53+ in The Origins of Virtue, or pp. 334-335 in The Blank Slate.) The prisoner's dilemma is a scenario in which two prisoners who committed a crime together are in separate rooms, being questioned about whether or not they committed the crime. If person A says person B committed the crime without any help from A, then B goes to jail and A goes free, and vice versa. If they both admit to the crime, then they both get lighter sentences. The dilemma is what each prisoner should do, cooperate with his partner or defect (incriminate his partner), not knowing what the other person will do.
The quandary is sometimes presented mathematically--how much do you gain and lose with each option. The bottom line is that "Whatever the other person does, you are better off defecting." (Ridley, p. 54). I think this is very much like the Tragedy of the Commons, which explains why it's so hard to move forward on environmental issues.

I think the prisoner's dilemma is a clear-cut reason why we need a strong national defense. I would like it if someone in our group could explain to me why they might see this differently, because I just can't see it any other way. I realize that this has guided my basic political instincts for a long time. (Again, it's why I seem to agree with many "liberal" causes but sometimes end up voting with the conservatives.) It is not rational to expect the other side to cooperate--even more so when the other side are terrorists or totalitarian governments, because they have even less to lose by not cooperating-for example, in our society the government may be criticized by the citizens or voted out of office for not cooperating, but this won't happen in the totalitarian society. (And, it is a sad but stark fact that we in the West live lives of luxury compared to many others, so we have more to lose  on that count too.) Because democratic societies do have certain standards of openness and fairness, it is also easy for others to "cheat"--to say they will cooperate, but then defect. We are supposed to abide by standards of decency that other societies may not even hold--so doesn't that make it pretty easy for them to win?

I think it's important to always remind ourselves that evolutionary psychology doesn't say that these negative aspects of our psychology are okay and we should live with them; it just tells us what is, so that we can work on making a better society given the natures we are born with. From The Blank Slate, p. 336:

Many intellectuals have averted their gaze from the evolutionary logic of violence, fearing that acknowledging it is tantamount to accepting it or even to approving it.

However, The Origins of Virtue is supposed to be about how humans come to cooperate with each other despite these tendencies--so I should read on.