> On 27 Nov 2018, at 22:55, [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 > > <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. 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] > <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.
