> On 3 Dec 2018, at 10:35, Philip Thrift <cloudver...@gmail.com> wrote: > > > > On Sunday, December 2, 2018 at 8:17:54 PM UTC-6, Brent wrote: > > > On 12/2/2018 5:14 PM, Philip Thrift wrote: >> >> >> On Sunday, December 2, 2018 at 4:25:04 PM UTC-6, Brent wrote: >> >> >> On 12/2/2018 11:42 AM, Philip Thrift wrote: >>> >>> >>> On Sunday, December 2, 2018 at 8:13:48 AM UTC-6, agrays...@gmail.com <> >>> wrote: >>> >>> Obviously, from a one-world perspective, only one history survives for a >>> single trial. But to even grossly approach anything describable as >>> "Darwinian", you have to identify characteristics of histories which >>> contribute positively or negatively wrt surviving but I don't see an >>> inkling of that. IMO, Quantum Darwinism is at best a vacuous restatement of >>> the measurement problemt; that we don't know why we get what we get. AG >>> >>> >>> >>> >>> In the sum over histories interpretation - of the double-slit experiment, >>> for example - each history carries a unit complex number - like a gene - >>> and this gene reenforces (positively) or interferes (negatively) with other >>> history's genes in the sum. >> >> But I thought you said the ontology was that only one history "popped out of >> the Lottery machine"? Here you seem to contemplate an ensemble of >> histories, all those ending at the given spot, as being real. >> >> Brent >> >> >> >> >> All are real until all but one dies. >> RIP: All those losing histories. > > The trouble with that is the Born probability doesn't apply to histories, it > applies to results. So your theory says nothing about the probability of the > fundamental ontologies. > > Brent > > > > > > The probability distribution on the space of histories is provided by the > path integral.

I agree, and this statement can be made rather rigorously in the approach of Griffith and Omnes, except that Omnes eventually add an axiom of irrationality to extract a unique physical reality from the formalism. He said it, at least, explicitly: like saying “and now there is a miracle”. He says that at this stage, we need irrationalism. But that appears in the last ten sentences of a rather quite rational book. Well, the point is that we can generalise the Born rule for making sense on some probabilities on "consistent histories”. (But I am in trouble (now) on how to handle the GHZ state in term of (Griffith and Omnes)-histories (3-particle-GHZ = 1/sqrt(2)(up up up + down down down)). > > Backward causation, hidden variables and the meaning of completeness > [ https://www.ias.ac.in/article/fulltext/pram/056/02-03/0199-0209 ] > > Feynman’s path integral approach, calculation of the probability of the > outcome in question depends on an integration over the possible individual > paths between the given initial state and the given final state, each > weighted by a complex number. The fact that the weights associated with > individual paths are complex makes it impossible to interpret them as real > valued probabilities, associated with a classical statistical distribution of > possibilities. > > However, there is no such difficulty at the level of the entire ‘bundle’ of > paths which comprise the path integral. If we think of the hidden reality as > the instantiation not of one path rather than another but of one entire > bundle rather than another, then the quantum mechanical probabilities can be > thought of as classical probability distributions over such elements of > reality. (For example, suppose we specify the boundary conditions in terms of > the electron source, the fact that two slits are open, and the fact that a > detector screen is present at a certain distance on the opposite side of the > central screen. We then partition the detector screen, so as to define > possible outcomes for the experiment. For each element O_i of this partition, > there is a bundle B_i of Feynman paths, constituting the path integral used > in calculating the probability of outcome O_i . We have a classical > probability distribution > over the set of such B_i . > > One could stop at history bundles as the sample space, or the "hidden > reality" could be that one history is selected at random from the history > bundle. That could occur with time symmetry (retrocausality): The one path is > chosen at random from a history bundle at the source in the present from the > distribution determined on the history bundles in the future. With mechanism, the randomness and the unicity is a first person (plural) experience only, and seems to me no more astonishing than in the amoeba duplication, or than in the Helsinki—> Washington/Moscow duplication, as seen from the first person ways. 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 everything-list+unsubscr...@googlegroups.com > <mailto:everything-list+unsubscr...@googlegroups.com>. > To post to this group, send email to everything-list@googlegroups.com > <mailto:everything-list@googlegroups.com>. > 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 everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.