It’s not clear to me exactly what your position is, so I will assume you’re a thirder. If this is not the case and I have misinterpreted your position, feel free to correct me at will.
I disagree with you because I think that “subjective probability” is indeed what one should be asking, because only in this way one can believe different things depending on the bet made.
For example, let me attack your Monty-halled SB:
in an urn there are two white balls and a red one: one is extracted, if the ball is white the SB is awaken and interviewed once, if red is extracted then she’s interviewed one million times;
the sleeping beauty must decide beforehand whether she wants to bet on red or white. If she’s correct then she wins a million dollar.
If the thirder was always the correct answer, one could calculate that the red branch gets beforehand a probability of .999999, so the SB would always bet on the red and lose on average on the ‘halfer’ beauty.
Yes, but to be clear, my ‘answer’ is that theres’ no universal right answer: whenever the question asked is about the single anthropic position, thirders are correct, when it’s about the global structure of the branch they’re in, halfers’ is the correct answer. The argument would have carried through even if I had not destroyed the symmetry between the branches, because in that case it would have been that both positions would have won on average, and so there was no ‘obviously’ correct answer, but I think this way is clearer, because in the Monty Hall version one of the branch gets almost all probability mass.
Only one of those questions is asked in the problem proper. The other is the product of a poor rephrasing or somebody seeking the question to which their incorrect answer ceases to be incorrect.
I don’t know / care to track the problem as it was originally formulated. If it’s as you say so, then I wholeheartedly agree that the correct answer is 1⁄3. It’s just nice to be able to reason correctly about this kind of anthropic questions and to be aware that the answer changes (which is not a given in non Bayesian takes on probability).
It’s not clear to me exactly what your position is, so I will assume you’re a thirder. If this is not the case and I have misinterpreted your position, feel free to correct me at will.
I disagree with you because I think that “subjective probability” is indeed what one should be asking, because only in this way one can believe different things depending on the bet made.
For example, let me attack your Monty-halled SB:
in an urn there are two white balls and a red one: one is extracted, if the ball is white the SB is awaken and interviewed once, if red is extracted then she’s interviewed one million times;
the sleeping beauty must decide beforehand whether she wants to bet on red or white. If she’s correct then she wins a million dollar.
If the thirder was always the correct answer, one could calculate that the red branch gets beforehand a probability of .999999, so the SB would always bet on the red and lose on average on the ‘halfer’ beauty.
You’ve changed the problem to suit your answer.
Yes, but to be clear, my ‘answer’ is that theres’ no universal right answer: whenever the question asked is about the single anthropic position, thirders are correct, when it’s about the global structure of the branch they’re in, halfers’ is the correct answer.
The argument would have carried through even if I had not destroyed the symmetry between the branches, because in that case it would have been that both positions would have won on average, and so there was no ‘obviously’ correct answer, but I think this way is clearer, because in the Monty Hall version one of the branch gets almost all probability mass.
Only one of those questions is asked in the problem proper. The other is the product of a poor rephrasing or somebody seeking the question to which their incorrect answer ceases to be incorrect.
I don’t know / care to track the problem as it was originally formulated. If it’s as you say so, then I wholeheartedly agree that the correct answer is 1⁄3.
It’s just nice to be able to reason correctly about this kind of anthropic questions and to be aware that the answer changes (which is not a given in non Bayesian takes on probability).