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?
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