On Sunday, February 9, 2020 at 11:16:33 AM UTC-7, Brent 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] <javascript:>> > 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 >
*But doesn't decoherence theory, which I recall you like, use unitary time evolution in an attempt to solve the measurement problem? Or did I misread you? AG * > > > 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. > > >> > >>> 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? > > 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/19f37ad8-9992-4985-b0f7-a8c228ca9bd4%40googlegroups.com.
