> On 1 Dec 2018, at 17:12, [email protected] wrote: > > > > On Friday, November 30, 2018 at 8:53:43 AM UTC, Bruno Marchal wrote: > >> On 27 Nov 2018, at 22:55, [email protected] <javascript:> 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 >> >> <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 >> <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 > > I think that the comparison with Darwin makes sense, and in both case, there > are many “fittest” entities. > > IMO, it's a ridiculous comparison. If you affirm the MWI, then ALL histories > survive.
Only the relatively consistent one, and then with very different relative measure. If you go through the windows instead of taking the lift, you will survive in both case, but in the normal/Gaussian worlds (measure close to 1), you are severely injured in the first case, and not so in the second case. Bruno > If you deny the MWI, there's no model whatever of "fittest" to explain why > all histories cease to exist except the one measured for a single trial. The > only thing remarkable here is that I have to explain this. AG > > Evolution gives a tree, with many branches, and "quantum Darwinism” gives > rise too too many locally consistent histories. None select one individual > branche, ISTM. > > Bruno > > > >> >> - 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] <javascript:>. >> To post to this group, send email to [email protected] >> <javascript:>. >> Visit this group at https://groups.google.com/group/everything-list >> <https://groups.google.com/group/everything-list>. >> For more options, visit https://groups.google.com/d/optout >> <https://groups.google.com/d/optout>. > > > -- > 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] > <mailto:[email protected]>. > To post to this group, send email to [email protected] > <mailto:[email protected]>. > Visit this group at https://groups.google.com/group/everything-list > <https://groups.google.com/group/everything-list>. > For more options, visit https://groups.google.com/d/optout > <https://groups.google.com/d/optout>. -- 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.
