Again, I’m not saying that (“in-universe”) duplication is exactly the same as probability, and neither is everyone else. Duplication is like probability in, e.g., the following sense: Suppose you do a bunch of experiments involving randomization, and suppose that every time you perform the basic operation “pick one of N things, all equally likely, independently of other choices” what actually happens is that you (along with the rest of the universe) are duplicated N times, and each duplicate sees one of those N choices, and then all the duplicates continue with their lives. And suppose we do this many times, duplicating each time. Then in the long run almost all your duplicates see results that look like those of random choices.
I can, of course, see the inference from “in-universe duplication is not essentially the same as probability” + “in-universe duplication is essentially the same as cross-universe duplication” + “MWI says cross-universe duplication is essentially the same as probability” to “MWI is wrong”, at least if the essentially-the-same relation is transitive. But I disagree with at least one of those first two propositions; exactly which might depend on how we cash out “essentially the same as”.
(I’m not sure whether the paragraph above is exactly responsive to what you said, because you didn’t say anything about the distinction between in-universe and cross-universe duplication, which to me seems highly relevant, and because I’m not sure exactly what you mean by “duplication with a measure”. Feel free to clarify and/or prod further, if I have missed the point somehow.)
Again, I’m not saying that (“in-universe”) duplication is exactly the same as probability, and neither is everyone else. Duplication is like probability in, e.g., the following sense: Suppose you do a bunch of experiments involving randomization, and suppose that every time you perform the basic operation “pick one of N things, all equally likely, independently of other choices” what actually happens is that you (along with the rest of the universe) are duplicated N times, and each duplicate sees one of those N choices, and then all the duplicates continue with their lives. And suppose we do this many times, duplicating each time. Then in the long run almost all your duplicates see results that look like those of random choices.
I can, of course, see the inference from “in-universe duplication is not essentially the same as probability” + “in-universe duplication is essentially the same as cross-universe duplication” + “MWI says cross-universe duplication is essentially the same as probability” to “MWI is wrong”, at least if the essentially-the-same relation is transitive. But I disagree with at least one of those first two propositions; exactly which might depend on how we cash out “essentially the same as”.
(I’m not sure whether the paragraph above is exactly responsive to what you said, because you didn’t say anything about the distinction between in-universe and cross-universe duplication, which to me seems highly relevant, and because I’m not sure exactly what you mean by “duplication with a measure”. Feel free to clarify and/or prod further, if I have missed the point somehow.)