I wish that discussions of anthropics were clearer about metaphysical commitments around personal identity and possibility. I appreciated your discussions of this, e.g., in Section XV. I agree with what you, though, that it is quite unclear what justifies the picture “I am sampled from the set of all possible people-in-my-epistemic situation (weighted by probability of existence)”. I take it the view of personal identity at work here is something like “‘I’ am just a sequence of experiences S”, and so I know I am one of the sequences of experiences consistent with my current epistemic situation E. But the straightforward Bayesian way of thinking about this would seem to be: “I am sampled from all of the sequences of experiences S consistent with E, in the actual world”.
(Compare with: I draw a ball from an urn, which either contains (A) 10 balls or (B) 100 balls, 50% chance each. I don’t say “I am indifferent between the 110 possible balls I could’ve drawn, and therefore it’s 10:1 that this ball came from (B).” I say that with 50%, ball came from (A) and with 50% the ball came from (B). Of course, there may be some principled difference between this and how you want to think about anthropics, but I don’t see what it is yet.)
This is just minimum reference class SSA, which you reject because of its verdict in God’s Coin Toss with Equal Numbers. I agree that this result is counterintuitive. But I think it becomes much more acceptable if (1) we get clear about the notion of personal identity at work and (2) we try to stick with standard Bayesianism. mrcSSA also avoids many of the apparent problems you list for SSA. Overall I think mrcSSA’s answer to God’s Coin Toss with Equal Numbers is a good candidate for a “good bullet” =).
(Cf. Builes (2020), part 2, who argues that if you have a deflationary view of personal identity, you should use (something that looks extensionally equivalent to) mrcSSA.)
Awesome sequence!
I wish that discussions of anthropics were clearer about metaphysical commitments around personal identity and possibility. I appreciated your discussions of this, e.g., in Section XV. I agree with what you, though, that it is quite unclear what justifies the picture “I am sampled from the set of all possible people-in-my-epistemic situation (weighted by probability of existence)”. I take it the view of personal identity at work here is something like “‘I’ am just a sequence of experiences S”, and so I know I am one of the sequences of experiences consistent with my current epistemic situation E. But the straightforward Bayesian way of thinking about this would seem to be: “I am sampled from all of the sequences of experiences S consistent with E, in the actual world”.
(Compare with: I draw a ball from an urn, which either contains (A) 10 balls or (B) 100 balls, 50% chance each. I don’t say “I am indifferent between the 110 possible balls I could’ve drawn, and therefore it’s 10:1 that this ball came from (B).” I say that with 50%, ball came from (A) and with 50% the ball came from (B). Of course, there may be some principled difference between this and how you want to think about anthropics, but I don’t see what it is yet.)
This is just minimum reference class SSA, which you reject because of its verdict in God’s Coin Toss with Equal Numbers. I agree that this result is counterintuitive. But I think it becomes much more acceptable if (1) we get clear about the notion of personal identity at work and (2) we try to stick with standard Bayesianism. mrcSSA also avoids many of the apparent problems you list for SSA. Overall I think mrcSSA’s answer to God’s Coin Toss with Equal Numbers is a good candidate for a “good bullet” =).
(Cf. Builes (2020), part 2, who argues that if you have a deflationary view of personal identity, you should use (something that looks extensionally equivalent to) mrcSSA.)