> On 3 Dec 2018, at 10:35, Philip Thrift <[email protected]> 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, [email protected] <> >>> 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 [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.
