On Thursday, November 14, 2019 at 3:12:37 PM UTC-7, Bruce wrote: > > On Thu, Nov 14, 2019 at 10:58 PM Bruno Marchal <[email protected] > <javascript:>> wrote: > >> On 11 Nov 2019, at 12:35, Bruce Kellett <[email protected] <javascript:>> >> wrote: >> > > >> On Mon, Nov 11, 2019 at 8:37 PM Bruno Marchal <[email protected] >> <javascript:>> wrote: >> >> On 10 Nov 2019, at 20:01, Alan Grayson <[email protected] <javascript:>> >>> wrote: >>> >> >> >>> On Sunday, November 10, 2019 at 5:42:50 AM UTC-7, Bruno Marchal wrote: >>> >>> Once the cat is alive + dead, he remains in that state for ever. >>>> >>> >>> *Then how come we NEVER observe that state? AG* >>> >>> >>> Because the observable are defined by their possible definite outcome, >>> and for reason already explained, macroscopic superposition decoder, that >>> is get entangled with the environment at a very high speed. So, if you look >>> at the cat in the a+d state, you are duplicate almost immediately into a >>> guy seeing the cat alive + the guy seeing the cat dead, and QM explained >>> why they cannot interact, although they might interfere themselves. >>> >> >> That is exactly a preferred basis -- which you seem to want to deny. >> >> >> I have never denied a preferred basis, as preferred by the evolution of >> the type of observer we are (like molecular biological organism, where >> position plays an important role). >> > > As has been pointed out, evolution of observers plays no role in the > existence of a preferred basis. The preferred basis arises from the normal > physical interactions of quantum states with the environment. Observers > play no role in this process. That is the message of Everett -- we must > eliminate any mention of observers (or measurement) from our account of > physics. > >> What I deny is that the MWI implies that some base are more important in >> physics than other. >> > > That is where you are 100% wrong. The preferred basis, its existence and > development, is central to physics. Sure, we can describe Hilbert space in > any basis whatsoever, but we do not perceive Hilbert space -- the world we > perceive definitely has a preferred basis. > >> The universal wave function can be described in any base, but the >> internal observer will “choose” the base corresponding to their most useful >> sensory apparatus. >> > > No, again, it is not a matter of personal choice. The preferred basis is > determined by the basic dynamics of the physical world, independently of > any observer, or any observer's choice. > >> It is a bit like a planet and life: there are “preferred planet” having >> the right conditions for life to develop. Similarly, consciousness can only >> differentiate in the base in which Turing universal machine can also >> differentiate. >> > > It is not at all like the fact that only certain planets have the right > conditions for life. Life is irrelevant to the preferred basis. The > important concept, as Zurek has stressed in his development of Quantum > Darwinism, is the emergence of a classical world from the quantum > substrate. Central to this, is the possibility of the formation, in the > environment, of many copies of the information concerning the outcome of a > quantum process. These many copies are central to the possibility of many > observers coming to see the same result, and that leads to the emergence of > an objective classical world. It is this objective classical world that is > the basis of our experience, and it is that world that we are required to > explain by our physics. Given that we have access only to a limited subset > of the total information, we definitely have a mixed state -- this is the > origin (in quantum Darwinism) of quantum jumps. Zurek's insight here is > profound. > > In order for the basis to be irrelevant, we would have to have access to > all the copies of the information. If we have such access, then objectivity > is lost -- others cannot access the information without disturbing the > system. Consequently, independence of basis entails solipsism -- where only > one individual would control all the information, and he can order this in > any basis he likes. But that is not how things are in practice. > > Bruce >
OR, it could be that the Hilbert Space model of QM is flawed in implying that states can exist which can never be observed. AG -- 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 view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/4eac80df-e8fb-4410-892f-f34337e1473e%40googlegroups.com.
