Also, even without invoking the Born rule there is a result that if you consider a "pointer state" that records the relative fractions of different possible measurement results in a *series* of N systems prepared in the same initial state, and consider the limit as N approaches infinity, in this limit all the amplitude gets concentrated on the pointer state with the fractions that correspond to the probabilities for individual measurements predicted by the Born rule--see David Z Albert's comments at https://books.google.com/books?id=_HgF3wfADJIC&lpg=PP1&pg=PA238 and the paper discussing Mittelstaedt’s theorem at https://www.academia.edu/6975159/Quantum_dispositions_and_the_notion_of_measurement
Jesse On Wed, Aug 27, 2025 at 2:39 AM Quentin Anciaux <[email protected]> wrote: > Bruce, > > Everett’s original formulation describes a universal wavefunction evolving > unitarily, not discrete worlds with one observer per branch. Your argument > assumes this mapping, but it is an interpretative choice, not a result > derived from the Schrödinger equation. > > Also, your claim that all 2^N sequences have equal measure only holds if > amplitudes are treated as irrelevant. In standard quantum mechanics, > amplitudes directly determine observed frequencies via the Born rule, which > has strong experimental support. Ignoring amplitudes means you are no > longer analyzing Everett’s framework but a different model where the Born > rule indeed fails. > > To refute Everett with Born included, you would need to show that even > when squared amplitudes define a natural measure, the predicted observed > frequencies still fail. Assuming uniform sampling over sequences does not > establish that. > > This is why your derivation is not accepted: it relies on a hidden > premise, one observer per branch with uniform sampling, which is not part > of Everettian quantum mechanics. > > Quentin > > All those moments will be lost in time, like tears in rain. (Roy > Batty/Rutger Hauer) > > Le mer. 27 août 2025, 07:32, Bruce Kellett <[email protected]> a > écrit : > >> On Wed, Aug 27, 2025 at 3:26 PM Quentin Anciaux <[email protected]> >> wrote: >> >>> Bruce, >>> >>> If your derivation is as solid as you claim, then a skeptical referee is >>> exactly who you should want to convince. Repeating the same argument here >>> without engaging with the role of amplitudes will not make it any stronger. >>> You cannot dismiss amplitudes entirely and then claim to have explained why >>> measure must be uniform, that is circular. >>> >>> If you truly believe your reasoning refutes the Born rule within >>> Everett’s framework, then publishing it is the only way to settle the >>> matter. Otherwise, endlessly asserting it here looks less like confidence >>> and more like avoidance. >>> >>> Your entire argument hinges on assuming uniform observer sampling by >>> postulating one observer per branch. >>> >> >> The argument does not depend on this. This shows nothing more than that >> you have not understood the argument. >> >> But that is precisely the point under debate, not a derived result. If >>> you ignore the role of amplitudes in defining the structure of the >>> wavefunction, you're not engaging with Everett's formulation, only with >>> your own simplified model. >>> >>> Until you demonstrate why amplitudes should be irrelevant within unitary >>> evolution, claiming equal weights is just assuming your conclusion. >>> >> >> I think, rather, that you should show how the argument I have made >> depends on amplitudes when it clearly does not. It depends merely on the >> proportion of zero outcomes in each sequence. And that does not depend on >> the amplitudes. >> >> 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/CAFxXSLTqmwjWPL45KfJwEJRqr5_VOZETJZKZaCE3tZamgVBXbg%40mail.gmail.com >> <https://groups.google.com/d/msgid/everything-list/CAFxXSLTqmwjWPL45KfJwEJRqr5_VOZETJZKZaCE3tZamgVBXbg%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/CAMW2kAp6jiQmTmu%3D%2Bd1p0XFf1axT6%2BBSp4EMbna1ZJ5%2BvDp4jQ%40mail.gmail.com > <https://groups.google.com/d/msgid/everything-list/CAMW2kAp6jiQmTmu%3D%2Bd1p0XFf1axT6%2BBSp4EMbna1ZJ5%2BvDp4jQ%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/CAPCWU3LDe3qoLj_Kp1M9oxt1OR%3DXj2aGRVZuZwOr_t7b3Y6jWg%40mail.gmail.com.
