On Wednesday, November 28, 2018 at 8:13:21 AM UTC, Philip Thrift wrote: > > > > On Tuesday, November 27, 2018 at 6:07:41 PM UTC-6, [email protected] > wrote: >> >> >> >> On Tuesday, November 27, 2018 at 10:47:08 PM UTC, Philip Thrift wrote: >>> >>> >>> >>> On Tuesday, November 27, 2018 at 3:55:16 PM UTC-6, [email protected] >>> wrote: >>>> >>>> >>>> >>>> On Tuesday, November 27, 2018 at 8:43:55 PM UTC, Philip Thrift wrote: >>>>> >>>>> >>>>> >>>>> On Tuesday, November 27, 2018 at 2:05:04 PM UTC-6, [email protected] >>>>> wrote: >>>>>> >>>>>> >>>>>> >>>>>> On Tuesday, November 27, 2018 at 6:49:51 PM UTC, Philip Thrift wrote: >>>>>>> >>>>>>> >>>>>>> >>>>>>> On Tuesday, November 27, 2018 at 12:17:08 PM UTC-6, >>>>>>> [email protected] wrote: >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> On Tuesday, November 27, 2018 at 6:00:50 PM UTC, Philip Thrift >>>>>>>> wrote: >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> On Tuesday, November 27, 2018 at 8:43:35 AM UTC-6, >>>>>>>>> [email protected] wrote: >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> On Tuesday, November 27, 2018 at 9:27:46 AM UTC, Philip Thrift >>>>>>>>>> wrote: >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> On Monday, November 26, 2018 at 3:43:14 PM UTC-6, >>>>>>>>>>> [email protected] wrote: >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> *I checked the postulates in Feynman's Sums Over Histories (in >>>>>>>>>>>> link provided by Phil) and I see nothing related to waves, as >>>>>>>>>>>> expected, and >>>>>>>>>>>> thus nothing about collapse of anything. I would suppose the same >>>>>>>>>>>> applies >>>>>>>>>>>> to Heisenberg's Matrix Mechanics; no waves, no collapse. I suppose >>>>>>>>>>>> you >>>>>>>>>>>> could say they just produce correct probabilities, and imply >>>>>>>>>>>> nothing about >>>>>>>>>>>> relative states other than their probabilities (which wave >>>>>>>>>>>> mechanics does), >>>>>>>>>>>> but certainly nothing about consciousness. To summarize: you're >>>>>>>>>>>> right that >>>>>>>>>>>> they are "no collapse" theories, but IMO they say nothing about >>>>>>>>>>>> consciousness. AG* >>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> In terms of the path-integral (PI) interpretation [ interesting >>>>>>>>>>> lecture: >>>>>>>>>>> https://www.perimeterinstitute.ca/videos/path-integral-interpretation-quantum-mechanics >>>>>>>>>>> >>>>>>>>>>> ], there is in effect no waves or wave function, just paths, or >>>>>>>>>>> histories, >>>>>>>>>>> in the sum-over-histories (SOH) terminology. >>>>>>>>>>> >>>>>>>>>>> There is still "decoherence" in the SOH (a single history is >>>>>>>>>>> ultimately "realized"), but it could be called "selection": a >>>>>>>>>>> single >>>>>>>>>>> history is selected from the total ensemble of multiple and >>>>>>>>>>> interfering >>>>>>>>>>> histories. E.g. a single point on a screen is "hit" by a photon in >>>>>>>>>>> the >>>>>>>>>>> double-slit experiment. >>>>>>>>>>> >>>>>>>>>> >>>>>>>>>> *Does "selection" add any insight to the measurement problem; >>>>>>>>>> that is, why do we get what we get? And if not, what is its value? >>>>>>>>>> TIA, AG * >>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>> If you look at it as a "selection of the fittest" (one history >>>>>>>>> surviving from an ensemble of histories), then it's like a form of >>>>>>>>> quantum >>>>>>>>> Darwinism. The quantum substrate is a cruel world where all histories >>>>>>>>> (but >>>>>>>>> one) die. >>>>>>>>> >>>>>>>> >>>>>>>> That's not an explanation; rather, a vacuous statement of the >>>>>>>> result. AG >>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>> But that is a criticism of Darwinism (*natural selection*) in >>>>>>> general. >>>>>>> >>>>>> >>>>>> *Ridiculous comparison IMO. Darwinism posits a changing environment >>>>>> and competition among species for niches. Nothing comparable in Quantum >>>>>> Darwinism other than all outcomes fail except for one which succeeds in >>>>>> each single trial, which we knew from the get-go. AG* >>>>>> >>>>>>> >>>>>>> *Quantum Darwinism* is a theory claiming to explain the emergence >>>>>>> of the classical world >>>>>>> <https://en.wikipedia.org/wiki/Classical_physics>from the quantum >>>>>>> world <https://en.wikipedia.org/wiki/Quantum_mechanics> as due to *a >>>>>>> process of **Darwinian >>>>>>> <https://en.wikipedia.org/wiki/Charles_Darwin> natural selection >>>>>>> <https://en.wikipedia.org/wiki/Natural_selection>*; where the many >>>>>>> possible quantum states >>>>>>> <https://en.wikipedia.org/wiki/Quantum_states> are selected against >>>>>>> in favor of a stable pointer state >>>>>>> <https://en.wikipedia.org/wiki/Pointer_state>. >>>>>>> [ https://en.wikipedia.org/wiki/Quantum_Darwinism ] >>>>>>> >>>>>>> - pt >>>>>>> >>>>>>> >>>>>> >>>>> >>>>> >>>>> As for "competition for niches", the histories are in a sense >>>>> competing. Perhaps there is some conservation principle at work, so only >>>>> one history can win. >>>>> >>>>> I don't know. Physicists don't know. We're even. :) >>>>> >>>> >>>> *Darwin had a theory or proposal to explain why some changes occur and >>>> persist, but Quantum Darwinism doesn't, as far as I can tell. AG * >>>> >>>>> >>>>> - >>>>> >>>> >>> What was the "why" of Darwin's theory? >>> >> >> *Darwin didn't know about DNA, but he hypothesized that specie could >> change in time, and he could explain the persistence of some traits and >> non-persistence of others by the process of natural selection. In Quantum >> Darwinism, there is no concept AFAICT that explains why all paths but one >> cease to exist. There is nothing comparable to Darwin's natural selection. >> AG * >> >>> >>> >>> > > > The analogy (mapping) between biological selection and quantum selection > isn't perfect. But there is no better idea. >
*But it's just a repackaged label for something we already know -- that only one history "survives" for a single trial -- so IMO it's worthless. AG * > > - pt > -- 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 post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
