On Mon, Jun 10, 2019 at 4:34 PM Philip Thrift <[email protected]> wrote:
> On Sunday, June 9, 2019 at 11:52:02 PM UTC-5, Bruce wrote: >> >> On Wed, Jun 5, 2019 at 11:25 PM Philip Thrift <[email protected]> wrote: >> >>> On Wednesday, June 5, 2019 at 7:56:41 AM UTC-5, Philip Thrift wrote: >>>> >>>> On Wednesday, June 5, 2019 at 6:45:32 AM UTC-5, Lawrence Crowell wrote: >>>>> >>>>> On Tuesday, June 4, 2019 at 10:22:51 PM UTC-5, Bruce wrote: >>>>>> >>>>>> On Wed, Jun 5, 2019 at 1:15 PM Philip Thrift <[email protected]> >>>>>> wrote: >>>>>> >>>>>>> >>>>>>> As for quantum stochastic retrodependency (which physicists avoid >>>>>>> like vampires avoid sunlight), it simplifies the "puzzles" of QM, >>>>>>> meaning >>>>>>> that, for the most part, the articles you see talking about the "spooky >>>>>>> action at a distance" or "many wolds" of QM you can dump in the trashcan >>>>>>> and save a lot of time! >>>>>>> >>>>>> >>>>>> The trouble is that these retrocausal "explanations" do not actually >>>>>> explain anything! They sound like they should: "The formation of the EPR >>>>>> pair depends on the future setting of the polarises as well as on the >>>>>> state >>>>>> preparation." (Or something similar). But no detailed dynamics are ever >>>>>> given, and the supposed explanation is even more mystical than "spooky >>>>>> action at a distance...." >>>>>> >>>>>> Bruce >>>>>> >>>>> >>>>> Bingo --- ting ding ting ding ... . Thanks Bruce. Since QM is time >>>>> symmetric or invariant in its form with respect to time direction whether >>>>> you define time forwards or backwards, or do so for some partition of a >>>>> density matrix or wave, makes no difference. Retrocausality in effect >>>>> solves nothing. Nonlocality and the contextual nature of QM, eg the >>>>> Mermin-Peres square that gives Kochen-Specker, have no definition with >>>>> respect to any time direction. If you have locality in QM then it is still >>>>> not possible to think meaningfully of counterfactual definiteness (CFD), >>>>> or >>>>> if QM is regarded as nonlocal only then can you have CFD, such as with >>>>> Many >>>>> Worlds Interpretation. It makes no difference whether the observables >>>>> measured are considered forwards or backwards evolving. >>>>> >>>>> LC >>>>> >>>> >>>> >>>> Retrocausality in effect solves nothing. >>>> >>>> It solves wasting any time reading papers about QM many worlds, >>>> non-locality, all the nonsense you read today. >>>> >>>> [If one views QM as a generalized measure on a space of histories, then >>>> one sees not only how quantal processes differ from classical stochastic >>>> processes (the main difference, they satisfy different sum rules), but also >>>> how closely the two resemble each other.] >>>> via Rafael Sorkin >>>> >>>> @philipthrift >>>> >>> >>> >>> Anyway, as you know well, I "adopted" the retrocausal view 20 years ago >>> via* Victor J. Stenger,* who pointed of course to Huw Price. >>> >> >> >> Apart from not solving anything, and the problem of the absence of any >> dynamical explanation as to how retrocausality might work to eliminate >> non-locality, the real problem is that retrocausal explanations have been >> ruled out experimentally. >> >> The seminal experiment by Aspect, et al., published in 1982 really put >> the last nail in the coffin of retrocausal explanations. The point is that >> in Aspect's experiment, the polariser settings were chosen while the >> photons were in flight -- in other words, at some time after the singlet >> pair was created. So there is no way the photons, travelling back in time >> at the speed of light, could ever reach the original singlet state after >> they had detected the polariser setting. The best they could do would be to >> carry the polariser setting back half way, but no way could they reach back >> to the interaction that created the original singlet state. >> >> So all these years, Huw Price and his cronies have been talking absolute >> rubbish -- their theory has already been falsified by experiment. >> >> Bruce >> > > > Rubbish. A complete misunderstanding of quantum mechanics. > > Retrocausal hidden variable models are completely compatible with > experiments, unless QM itself is wrong. > If retrocausality is right, then QM itself is certainly wrong. In the EPR situation, the singlet state is rotationally symmetric in standard QM, and this cannot be the case if that state is dependent on the future polariser settings. Conversely, if QM is right, retrocausality is impossible. 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 on the web visit https://groups.google.com/d/msgid/everything-list/CAFxXSLQDF3yRJo48%3DS613zjst1Sh1-Wu7qTjjdWBQvCOW_SFWA%40mail.gmail.com.
