Ah, you’re right. So gain doesn’t achieve as much as I thought it did. Thanks for the references, though. I think the idea is also similar in spirit to a proposal of Jeffrey’s in him book The Logic of Decision; he presents an evidential theory, but is as troubled by cooperating in prisoner’s dilemma and one-boxing in Newcomb’s problem as other decision theorists. So, he suggests that a rational agent should prefer actions such that, having updated on probably taking that action rather than another, you still prefer that action. (I don’t remember what he proposed for cases when no such action is available.) This has a similar structure of first updating on a potential action and then checking how alternatives look from that position.
Ah, you’re right. So gain doesn’t achieve as much as I thought it did. Thanks for the references, though. I think the idea is also similar in spirit to a proposal of Jeffrey’s in him book The Logic of Decision; he presents an evidential theory, but is as troubled by cooperating in prisoner’s dilemma and one-boxing in Newcomb’s problem as other decision theorists. So, he suggests that a rational agent should prefer actions such that, having updated on probably taking that action rather than another, you still prefer that action. (I don’t remember what he proposed for cases when no such action is available.) This has a similar structure of first updating on a potential action and then checking how alternatives look from that position.