And then -- I hope -- you would cooperate.
Why do you hope I'd let a billion people die (from a proposed quantification in another comment)?
This is actually rather different from a classic PD, to the extent that Cooperate (cooperate) is not the collectively desirable outcome.
Payoffs: You(Creationist): Defect(D): 1 Billion live D(C): 3 Billion live C(D): 0 live C(C): 2 Billion live
Under the traditional PD, D(C) is best for you, but worst for him. Under this PD, D(C) is best for both of you. He wants you to defect and he wants to cooperate; he just doesn't know it. Valuing his utility does not save this like it does the traditional PD. Assuming he's vaguely rational, he will end up happier if you choose to defect, regardless of his choice. Furthermore, he thinks you will be happier if he defects, so he has absolutely no reason to cooperate.
If only by cooperating can you guarantee his cooperation, you should do so. However the PD generally assumes such prior commitments are not possible. And unlike the traditional PD, C(C) does not lead to the best possible collective outcome. Thus, you should try your hardest to convince him to cooperate, then you should defect. He'll thank you for it when another billion people don't die.
The medical situation is more confusing because I don't think it's realistic. I sincerely doubt you would have two vaguely rational doctors who would both put 99% confidence on a diagnosis knowing that another doctor was at least 99% confident that that diagnosis was incorrect. Thus, you should both amend your estimates substantially downwards, and thus should probably cooperate. If you take the hypothetical at face value, it seems like you both should defect, even though again D(C) would be the optimal solution from your perspective.
The real problem I'm having with some of these comments is that they assume my decision to defect or cooperate affects his decision, which does not seem to be a part of the hypothetical. Frankly I don't see how people can come to this conclusion in this context, given that it's a 1-shot game with a different collective payoff matrix than the traditional PD.
I spoke yesterday of the epistemic prisoner's dilemma, and JGWeissman wrote:
To which I said:
And lo, JGWeissman saved me a lot of writing when he replied thus:
I make one small modification. You and your creationist friend are actually not that concerned about money, being distracted by the massive meteor about to strike the earth from an unknown direction. Fortunately, Omega is promising to protect limited portions of the globe, based on your decisions (I think you've all seen enough PDs that I can leave the numbers as an excercise).
It is this then which I call the true epistemic prisoner's dilemma. If I tell you a story about two doctors, even if I tell you to put yourself in the shoes of one, and not the other, it is easy for you to take yourself outside them, see the symmetry and say "the doctors should cooperate". I hope I have now broken some of that emotional symmetry.
As Omega lead the creationist to the other room, you would (I know I certainly would) make a convulsive effort to convince him of the truth of evolution. Despite every pointless, futile argument you've ever had in an IRC room or a YouTube thread, you would struggle desperately, calling out every half-remembered fragment of Dawkins or Sagan you could muster, in hope that just before the door shut, the creationist would hold it open and say "You're right, I was wrong. You defect, I'll cooperate -- let's save the world together."
But of course, you would fail. And the door would shut, and you would grit your teeth, and curse 2000 years of screamingly bad epistemic hygiene, and weep bitterly for the people who might die in a few hours because of your counterpart's ignorance. And then -- I hope -- you would cooperate.