On Friday, April 15, 2022 at 12:41:03 PM UTC-6 meeke...@gmail.com wrote:

> > > On 4/14/2022 2:00 PM, George Kahrimanis wrote: > > On Wednesday, April 13, 2022 at 8:55:48 PM UTC+3 meeke...@gmail.com > (Brent) wrote: > > Decoherence has gone part way in solving the when/where/what basis >> questions, but only part way. >> > > As I wrote at the end of my first reply to your message, I share your > concern about decoherence but I see the glass as half-full; that is, with a > little more subtlety I hope that the matter can be formulated in clear > terms. > > Surely collapse is easier to handle as a general concept (except, on the > other hand, that it requires new dynamics). I forgot to mention that *my > argument for deriving the Born Rule works with collapse, too* -- so it is > an alternative to Gleason's theorem. > > Here I define colapse as an irreversible process, violating unitarity of > course, and I keep it separate from randomisation. The latter means that > each outcome is somehow randomised -- an assumption we can do without. > > *Collapse can also be described in a many-world formulation!* It differs > from the no-collapse MWI only in being irreversible. > > > If you can throw away low probability branches, what's to stop you from > throwing away all but one? You've already broken unitary evolution. If > you read Hardy's axiomatization of QM you see that the difference between > QM and classical mechanics turns on a single word in Axiom 5 Continuity: > There exists a *continuous *reversible transformation on a system between > any two pure states of that system. > > My argument in outline is > 1. assessment that MWI-with-collapse is workable; > 2. therefore, outcomes of small enough measure can be neglected in > practice; > > > Yes, I've wondered if a smallest non-zero probability could be defined > consistent with the data. > > 3. now Everett's argument can proceed, concluding that the Born Rule is a > practically safe assumption (to put it briefly). > > So I have replaced two assumptions of Gleason's theorem, randomisation and > non-contextuality, by the assessment of workability only. > > If you don't feel comfortable yet with formulating collapse in a > many-world setting, let us also assume randomisation (God plays dice), for > the sake of the argument, in a single-world formulation. That is, we ASSUME > the existence of probability; then the previous argument just guarantees > that this probability follows the Born Rule. > > > Assume? Randomness is well motivated by evidence. And it's more random > than just not knowing some inherent variable, because in the EPR experiment > a randomized hidden variable can on explain the QM result if it's non-local. > > > Of course I favour the first version of the argument, using the many-world > formulation of collapse, to avoid the "God plays dice" nightmare. > > > Why this fear of true randomness? We have all kinds of classical > randomness we just attributed to "historical accident". Would it really > make any difference it were due to inherent quantum randomness? Albrect > and Phillips have made an argument that there is quantum randomness even > nominally classical dynamics. https://arxiv.org/abs/1212.0953v3 > True randomness implies *unintelligibility*; that is, no existing physical process for *causing *the results of measurements. AG > > > Brent > > > Thanks for the comments so far, because they stirred my thinking and > motivated fresh ideas, some of which I hope will prove helpful and worth > discussing, if and when they mature. > > George K. > -- > 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 everything-li...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/everything-list/06930c0c-5537-4fb7-bf70-fd8c7d9859b0n%40googlegroups.com > > <https://groups.google.com/d/msgid/everything-list/06930c0c-5537-4fb7-bf70-fd8c7d9859b0n%40googlegroups.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 everything-list+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/e2a370ad-6787-47cd-95bb-2819484a239bn%40googlegroups.com.