> On 1 May 2018, at 20:47, Brent Meeker <[email protected]> wrote: > > > > On 5/1/2018 9:01 AM, Bruno Marchal wrote: >> >>> On 29 Apr 2018, at 19:59, Brent Meeker <[email protected] >>> <mailto:[email protected]>> wrote: >>> >>> >>> >>> On 4/29/2018 8:53 AM, Bruno Marchal wrote: >>>>>> But that's my question: Why isn't it the same? And even if it's not how >>>>>> would be know? The "conscious" quantum computer assures us that it not >>>>>> only detected that there was a welcher weg photon but that it's weg was >>>>>> known to the "consciousness" of the quantum computer, before it was >>>>>> erased. But why would we believe it? We already have these experiments >>>>>> in which we know the weg was available and could have been recorded, but >>>>>> was erased. So what is the "consciousness" that adds a secret-sauce to >>>>>> the experiment? >>>>> >>>>> Good question. I doubt that you can fool quantum mechanics by calling it >>>>> "consciousness". I think in this case the interaction with the welcher >>>>> weg photon would amount to sufficient decoherence -- basically >>>>> information was extracted that was not restored. Also, of course, if the >>>>> QC "forgets" what it did, how can it report on the fact that it did >>>>> anything. How can we believe that it actually knew which slit at some >>>>> point? >>>> >>>> Because in Deutsch experiment, not everything has been erased, notably the >>>> memory that he has known the result. He would say something like: I >>>> remember doing the measurement and writing it in the enveloppe. Now the >>>> envelop has been erased, and I can’t remember its content, but I >>>> definitely remember having known the content. >>> >>> But two questions remain. First, the empirical question of whether this >>> erasure is enough to restore interference. >> >> I do not see why it would not been enough … in theory. You need only a >> computer able to forget a memory, but not some meta-memory that it has >> recorded a definite result. It isa bit like remembering we have done a >> dream, without being able to remember any of its content. >> >> In practice, that might be very difficult, if not impossible. I am not sure. >> >> >> >>> Second, why should we believe the quantum computer. >> >> In Deutsch proposal, it is a human. > > No, it's a conscious quantum computer.
Yes. I was thinking to a human having said “yes” to a quantum digital doctor, but of course any Löbian machine accepting a quantum digital transplant would work. That is needed to avoid full decoherence, and fusing the memories to regain the interference of what the observer has seen. Obviously. (Not a quasi classical human). And that helps us to believe it, as it is like any human being, and not a mysterious unknown machine or alien. > It it were a human or other (quasi-) classical instrument decoherence would > happen when there was a detection of welcher weg and erasure would be > impossible. Absolutely. I was obviously thinking of a human with a quantum brain (which really any computer with enough “isolation” from the environment, which needs some topological “reliable” qubits (it is a thought experiment, it will not be done so soon!). Bruno > > Brent > >> And we can repeat the experience with many humans. If they have all that >> feeling of having done a measurement and have obtained a definite record >> without being able to say which one, I think this coule be taken as making >> the MWI more plausible than the Mono-W. >> >> >> >>> It is not like the classical case in which there is a fact-of-them-matter >>> about which slit I observed and I've simply forgotten it. But by quantum >>> erasing the information, there is no fact-of-the-matter as to welcher weg, >>> so what can it mean that the quantum consciousness once knew it and now >>> remembers something that didn't happen. >> >> I don’t think we need a quantum consciousness. It is just the usual “comp >> consciousness”. The consciousness differentiate into “I see up in a definite >> way” + “I see down in a definite way”. Both separates the memories of up >> (resp. down) from the meta-memory “What I saw was definite”, and then we >> erase only the memories of “up” and “down”, taking care to not erase the >> meta-memory, so both consciousness can fuse again, with the meta-memory of >> having see an single outcome, but cannot tell which one, and in principle we >> can get (back) the interference of up and down, as the meta-memory is >> independent of it (in principle). >> >> The something did happen (well with MW), only the memories of it has been >> completely erased, like in the usual quantum erasing experience. >> >> Bruno >> >> >> >> >>> >>> Brent >>> >>> -- >>> 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] >> <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] > <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.
