On Thu, Feb 6, 2025 at 9:57 AM Quentin Anciaux <allco...@gmail.com> wrote:
> Bruce, > > You’re trying to reduce the issue to my supposed "difficulty" with > randomness, but that’s not the point. The problem isn’t whether quantum > events are random—it’s whether probability has a meaningful foundation in a > single-history universe where only one sequence of events is ever realized. > > You keep appealing to repeated trials, but even with infinite repetitions, > some events with nonzero probability will never occur in the one and only > history that unfolds. That’s not a minor detail—that’s a fundamental > contradiction in the way probability is treated in a single-world > framework. If an event assigned a 30% probability never happens, then its > "probability" was meaningless in any real sense. It was never a real > possibility, just a number in an equation. > That is not a good argument. If something of supposed probability 30% does not occur in,say, 100 trials, then your prior estimate of the probability is wrong. Probability theory tells you how many occurrences of low-probability events you can expect in a particular number of trials. If those probability estimates are not fulfilled, then your prior probability estimates are wrong. So it is wrong to say that low probability events will never ccur, no matter how many trials you run. Probability theory tells you what you can expect, and when low probability events can be expected to occur (or not occur) in some sequence of trials. Many worlds theory can do no better than this, because it says that you ill never see those low probability branches, even if they exist. I don't see that this gets you any further ahead. Now, regarding the Born rule: You claim that MWI contradicts it, but your > argument assumes that every possible branch must exist in equal measure, > which is not what MWI predicts. The structure of the wavefunction naturally > leads to branches that reflect the Born probabilities because those > branches are weighted according to the squared amplitudes. > That is not true. If your theory, following Everett, is that the Schrodinger equation is all that there is, then it is a fact that the Schrodinger equation is insensitive to the coefficients, so branches do not get weighted in the way you assume. IThe claim that branches are 'weighted' by the coefficients is an additional assumption -- equivalent to the assumption of the Born rule. It’s not about equal-counted branching—it’s about the distribution of > measure across branches, which naturally results in Born-rule outcomes. > That is something that has to be proved, and despite many efforts, it still remains an unproven assumption. Your argument also ignores the fact that in a single-history universe, the > Born rule is just an imposed rule with no deeper explanation. Why do > probabilities follow this rule in a framework where only one history > exists? What forces the realized history to match the expected distribution? > Nothing 'forces' the realized history to match the Born rule expectations. The Born rule is an observed fact, and it is an assumption of the theory -- a brute fact about probabilities if you like. There is no deeper explanation for random occurrences. If probabilities are just random assignments with no deeper foundation, > then their success in predicting experimental results is equally mysterious > in a single-history view. > > MWI provides an actual mechanism for why the Born rule emerges: it follows > from the structure of the wavefunction itself. > That is simply not true. You might like it to be the case, but it has never been shown to be true. If it is true, you can give the proof here -- physics would be delighted..... Your argument, on the other hand, assumes the Born rule as a brute fact > without explaining why a single realized history should respect it in the > first place. That’s not an explanation—it’s just asserting that the math > works and ignoring the deeper implications. > That is the way it is. The Born rule is just a brute fact, and since it is a probability theory, there is no deeper 'mechanical' explanation. Bruce -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/everything-list/CAFxXSLRyhs2d7wCGSJNRxoc_-zr4bLUJvbT53UPHiyGpHRmeDw%40mail.gmail.com.
