> On 27 Apr 2018, at 02:55, Bruce Kellett <[email protected]> wrote: > > From: Brent Meeker < <mailto:[email protected]>[email protected] > <mailto:[email protected]>> >> >> On 4/26/2018 3:41 PM, Bruce Kellett wrote: >>> From: John Clark <[email protected] <mailto:[email protected]>> >>>> >>>> On Thu, Apr 26, 2018 at 2:02 PM, < >>>> <mailto:[email protected]>[email protected] >>>> <mailto:[email protected]>> wrote: >>>> >>>> > How many times must I remind you that Feynman explained that very >>>> clearly. >>>> >>>> 42. >>>> >>>> > Please repeat it. AG >>>> >>>> I originally sent this on December 14 2017: >>>> >>>> David Deutsch proposed a test of Many Worlds about 30 years ago in his >>>> book "The Ghost In The Atom", but it would be very difficult to perform. >>>> The reason it's so difficult to test is not the Many World's theory >>>> fault, the reason is that the conventional view says that conscious >>>> observers obey different laws of physics, many worlds says they do not, so >>>> to test who's right we need a mind that uses quantum properties. Quantum >>>> Computers have advanced enormously over the last 30 years so I wouldn't be >>>> surprised if it or something very much like it is actually performed in >>>> the decade or two. >>>> >>>> An intelligent quantum computer shoots photons at a metal plate one at a >>>> time that has 2 small slits in it, and then the photons hit a photographic >>>> plate. Nobody looks at the photographic plate till the very end of the >>>> experiment. The quantum mind has detectors near each slit so it knows >>>> which slit the various electrons went through. After each photon passes >>>> the slits but before they hit the photographic plate the quantum mind >>>> signs a document saying that it has observed each and every photon and >>>> knows which slit each photon went through. It is very important that the >>>> document does not say which slit any photon went through, it only says >>>> that they went through one slit and one slit only and the mind has >>>> knowledge of which one. There is a signed document to this effect for >>>> every photon it shot. >>>> >>>> Now the mind uses quantum erasure to completely destroy its memory of >>>> which slit any of the photons went through; the only part remaining is the >>>> document which states that each photon went through one and only one slit >>>> and the mind (at the time) knew which one. Now develop the photographic >>>> plate and look at it. If you see interference bands then the many world >>>> interpretation is correct. If you do not see interference bands then there >>>> are no worlds but this one and the conventional quantum interpretation is >>>> correct. >>>> >>>> This works because in the Copenhagen interpretation when the results of a >>>> measurement enters the consciousness of an observer the wave function >>>> collapses, in effect all the universes except one disappear without a >>>> trace so you get no interference. In the many worlds model all the other >>>> worlds will converge back into one universe because information on which >>>> slit the various photons went through was the only thing that made one >>>> universe different from another, so when that was erased they became >>>> identical again and merged, but their influence will still be felt, you'll >>>> see indications that the photon went through slot A only and indications >>>> it went through slot B only, and that's what causes interference. >>> >>> Quantum erasure involves more than just forgetting what happened. What >>> about Zurek's "many records in the environment". If you know what happened, >>> many traces of that result remain -- even if your memory is erased. Deutsch >>> on the wrong track, yet again! >> >> Deutsch knows the difference, and he specifies quantum erasure, which >> implies that the detection of welcher weg is never classical, i.e. it is >> not decohered into the environment since if it were it could not be quantum >> erased. Which is the point of my remark that maybe all that would be proved >> is that quantum "detection" can't be conscious. I'm pretty sure >> consciousness is a purely classical phenomenon. So Deutsch's scheme to >> detecting welcher-weg but erasing the knowledge may retain the interference >> pattern but just prove that quantum knowledge is not conscious...something >> Borh might well say. > > My point was that if there is a record that a measurement was made, something > irreversible has been extracted from the experiment. If the QC is > "conscious", then it has to interact with something to make this irreversible > record, so its quantum state is irreversibly changed. But you are probably > right: if there is no decoherence, then there is no consciousness, since > consciousness involves irreversible memory.
All computations can be done in a reversible way. The basic idea is that we can discard memories instead of erasing them, and that idea is coherent with physics and mechanism. A theory of consciousness needs only local irreversibility, not a global one, and that is what happens in the wave branches in QM (without collapse), and in any quantum universal dovetailer. Why this win the “measure problem” remains to be justified, but there are progress in that direction. Bruno > > Bruce > > > -- > 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.
