> On 23 Feb 2020, at 07:04, 'Brent Meeker' via Everything List > <[email protected]> wrote: > > > > On 2/22/2020 9:50 PM, Bruce Kellett wrote: >> On Sun, Feb 23, 2020 at 4:30 PM 'Brent Meeker' via Everything List >> <[email protected] <mailto:[email protected]>> >> wrote: >> On 2/22/2020 7:11 PM, Bruce Kellett wrote: >>> >>> The trouble is that such a procedure is entirely arbitrary. The only >>> probability that one could objectively assign to say, W, on each Bernoulli >>> trial is one, since W certainly occurs for each trial. In other words, >>> there is no natural probability associated with this duplication process, >>> so imposing one is ad hoc and arbitrary. >>> >>> In MWI, it seems that Carroll gives the conventional answer -- weights are >>> arbitrarily assigned to branches according to the branch amplitude (modulus >>> of the coefficient squared). This is arbitrary too, designed merely to give >>> the same answer that is naturally obtained in the single world case. What I >>> object to about this is not only its arbitrariness, but also the fact that >>> it is advertised as a "derivation" from the SWE, when it is no such thing. >>> It is arbitrarily imposed. >> >> It's imposed. But it's hardly arbitrary. First, it agrees with experiment. >> Second, Gleason's theorem shows it's the only mathematically consistent >> measure that could be used as a probability. And Zurek tries to prove it's >> implied by symmetry considerations. >> >> It is imposed in such a way as to agree with experiment, yes. But that is >> how the Born rule was arrived at in the first instance. Consequently, MWI is >> no better than Copenhagen in this respect. Gleason's theorem is only of use >> if you first assume that there is a probability distribution -- that the >> theory is probabilistic. But Everett is deterministic, not probabilistic. > > And Everett recognized the problem and tried to derive the Born rule. But I > see as just overselling MWI. So it needs an axiom of probability added to > the deterministic evolution...no problem.
Or, as some people think Everett did, to appeal to the fist person indeterminacy on all the relative sate accessible from what we are preparing when doing a measurement. > The problem that remains is decoherent diagonalization of the reduced > density matrix is only FAPP. Schlosshauer talks about doing a Schmidt > decomposition to make it strictly diagonal; but he recognizes that's just > mathematical transformation with not physical counterpart. Schlosshauer and Fine’s paper is rather good indeed. Bruno > > Brent > >> >> Zurek tries to explain it by symmetry considerations. But the basis of his >> argument is the assumption that equal amplitudes imply equal probabilities. >> Since the amplitudes do not affect the Everett branching, this >> is ad hoc -- not a derivation. >> >> 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] >> <mailto:[email protected]>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/everything-list/CAFxXSLT-eCT5NePLEZVSw%3Dc%2BYafeNoW8nCYvLJQtHeDiEe4Gwg%40mail.gmail.com >> >> <https://groups.google.com/d/msgid/everything-list/CAFxXSLT-eCT5NePLEZVSw%3Dc%2BYafeNoW8nCYvLJQtHeDiEe4Gwg%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] > <mailto:[email protected]>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/everything-list/de8b9567-2f67-4ef5-567e-28847808d803%40verizon.net > > <https://groups.google.com/d/msgid/everything-list/de8b9567-2f67-4ef5-567e-28847808d803%40verizon.net?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 on the web visit https://groups.google.com/d/msgid/everything-list/DEB8CF26-2536-43E5-917B-FC41FDA916CD%40ulb.ac.be.
