> On 9 Feb 2020, at 19:16, 'Brent Meeker' via Everything List > <[email protected]> wrote: > > > > On 2/9/2020 12:48 AM, smitra wrote: >> On 08-02-2020 07:00, Bruce Kellett wrote: >>> On Sat, Feb 8, 2020 at 4:21 PM smitra <[email protected]> wrote: >>> >>>> On 08-02-2020 05:19, Bruce Kellett wrote: >>>> >>>>> No, I am suggesting that Many-worlds is a failed theory, unable to >>>>> account for everyday experience. A stochastic single-world theory >>>> is >>>>> perfectly able to account for what we see. >>>>> >>>>> Bruce >>>> >>>> Stochastic single word theories make predictions that violate those >>>> of >>>> quantum mechanics. >>> >>> No they don't. When have violations of the quantum predictions been >>> observed? >> >> A single world theory must violate unitary time evolution, it has to assume >> a violation of the Schrodinger equation. But there is no experimental >> evidence for violations of the Schrodinger equation. > > Except for every measurement ever made of a quantum variable. > > Brent > >> While one can make such assumptions and develop a formalism based on this, >> the issue is then that in the absence of experimental proof that the >> Schrodinger equation is going to be violated, one should not claim that such >> a model is superior than another model that doesn't imply any new physics. >> >> The MWI may have some philosophical weaknesses like the derivation of the >> Born rule but the pragmatic variant of it where you just assume the Born >> rule is clearly superior to any other model where you're going to just >> assume that the known laws of physics are going to be violated to get to a >> model that to you looks more desirable from a philosophical point of view. >> >>> >>>> If the MWI (in the general sense of there existing a >>>> multiverse rather than any details of how to derive the Born rule) >>>> is >>>> not correct, then that's hard to reconcile with known experimental >>>> results. >>> >>> All experimental results to date are consistent with a single-world >>> theory. There are several possibilities for such a theory, but to >>> date, experiment does not distinguish between them. >> >> Single world theories require a violation of unitary time evolution of a >> perfectly isolated system. No experiment has ever observed this. > > Because a perfectly isolated system can't be observed.
>From outside. >From inside that remains possible, and if there is a physical universe, then >we have an example. > >>> >>>> New physics that so far has never been observed needs to be >>>> assumed just to get rid of the Many Worlds. Also, this new physics >>>> should appear not at the as of yet unprobed high energies where the >>>> known laws of physics could plausibly break down, instead it would >>>> have >>>> to appear at the mesoscopic or macroscopic scale where the laws of >>>> physics are essentially fixed. >>> >>> Bohm's theory does not require as-yet-unobserved new physics. GRW do >>> postulate a new physical interaction, but that is below the level of >>> current experimental detectability. >> >> Bohm theory is not equivalent to QM, it only becomes equivalent to QM if one >> imposes a condition known as "quantum equilibrium". In general, Bohm theory >> in a condition of quantum non-equilibrium leads to violations of the Born >> rule. See here for details: >> >> https://en.wikipedia.org/wiki/Quantum_non-equilibrium >> >> Then without any experimental evidence for the additional features of Bohm >> theory such as the signatures of quantum non-equilibrium, why would be >> prefer it over and above a theory that doesn't make such assumptions? One >> would have to have very strong theoretical objections against the theory. In >> case of the Standard Model one can predict that it will break down at very >> high energies. But I don't see why the MWI in the pragmatic sense where one >> assumes the Born rule is so bad that it merits considering alternative >> theories, particularly if those alternative theories make lots of unverified >> assumptions about new physics in domains where new physics is thought to be >> unlikely to appear. >>> >>> Besides, why should you assume that the Schrodinger equation is the >>> ultimate physical law? >> >> It may be false, but absent experimental evidence that it is indeed false, >> theories that imply that it's false shouldn't get the benefit of the doubt >> just because they imply a single world. > > Even though a single world is a well confirmed and often repeated empirical > observation? Yes. To avoid solipsism or cosmo-solipisme … Bruno > > Brent > > -- > 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/462c261e-5058-cef4-55ab-bc34dc22aff2%40verizon.net. -- 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/64529D8B-A95E-4C1A-9644-C12190F080AC%40ulb.ac.be.
