Bruce, You claim there's "no mechanism" for assigning observer instances according to amplitude, but that’s just asserting ignorance as proof. The wavefunction already assigns amplitude-based structure to branches via unitary evolution and decoherence. The real question is whether measure naturally corresponds to observer frequencies—which is exactly what the Born rule states and what attempts at derivation (e.g., decision theory, self-locating uncertainty) try to formalize.
Also, the idea that a "branch encompasses the whole world" is a rough classical approximation, not a fundamental quantum principle. If the wavefunction remains a continuous superposition, then what we call a branch is just a macroscopic partition of underlying structure, not a single discrete entity. Observer instances scale with measure because the amplitudes evolve deterministically, and decoherence prevents low-measure branches from contributing significantly to experience. Dismissing this as a "pipe dream" isn’t an argument—it's just an unwillingness to engage with the actual problem. If you want to claim MWI can't produce the Born rule, you need more than just repeating that you don't see how it happens. Again please publish and get the glory with your refutation. Quentin Le ven. 21 févr. 2025, 06:39, Bruce Kellett <[email protected]> a écrit : > On Thu, Feb 20, 2025 at 6:17 PM Quentin Anciaux <[email protected]> > wrote: > >> Le jeu. 20 févr. 2025, 07:55, Brent Meeker <[email protected]> a >> écrit : >> >>> What does it mean to have more than one observer in a branch? A branch >>> forms because the result is orthogonal to the other different results. Of >>> course any number of persons can observe it, which by construction means >>> they are in that branch. Is that what you mean? >>> >>> Brent >>> >> >> Brent, >> >> A branch isn't a single discrete entity—it's a region in the wavefunction >> where decoherence prevents interference. The distinction matters because if >> the wavefunction remains a superposition of infinite components, then what >> we call a "branch" is just an approximate partition, not a fundamental unit. >> >> Saying "one observer per branch" assumes a sharp branching structure, but >> if the wavefunction maintains an underlying continuous structure, then what >> we experience as "branches" are really clusters of high-measure observer >> instances. More than one observer in a branch means that, within that >> region of the wavefunction, there are exponentially more instances of an >> observer experiencing a high-amplitude outcome than a low-amplitude one. >> >> In other words, observer count isn't tied to branch count—it's tied to >> measure. What matters isn’t how many "branches" exist but how many copies >> of an observer exist in each, which is why most observers see outcomes >> aligning with the Born rule. >> > > I can see at least a couple of problems with this. In the first instance, > a 'branch' encompasses the whole world, so if you want more than one person > on each branch, you have the entire population of the world on each branch. > Unfortunately, the same population can be found on every branch, so that > does not give you the necessary partitioning according to branch weight. > > That is the second main issue with this idea: there is no mechanism for > assigning extra observers to branches according to branch weights (or the > amplitude squared, which is just the Born probability). It is all just a > romantic pipe dream with no basis in mathematics, physics, or reality. > > 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 [email protected]. > To view this discussion visit > https://groups.google.com/d/msgid/everything-list/CAFxXSLQbQtG0nWiUhk6fhnk6cRM%2BJ6eqNbOsfoYn88rncF2HXQ%40mail.gmail.com > <https://groups.google.com/d/msgid/everything-list/CAFxXSLQbQtG0nWiUhk6fhnk6cRM%2BJ6eqNbOsfoYn88rncF2HXQ%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > -- 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 [email protected]. To view this discussion visit https://groups.google.com/d/msgid/everything-list/CAMW2kAqj37deOwffb6NrUiDd-XbpgxgLLhVya%2Bke%3Doyb9ACPww%40mail.gmail.com.
