On Thursday, November 14, 2019 at 3:37:43 PM UTC-7, Alan Grayson wrote: > > > > 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]> wrote: >> >>> On 11 Nov 2019, at 12:35, Bruce Kellett <[email protected]> wrote: >>> >> >> >>> On Mon, Nov 11, 2019 at 8:37 PM Bruno Marchal <[email protected]> wrote: >>> >>> On 10 Nov 2019, at 20:01, Alan Grayson <[email protected]> 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 >
I forget if I raised this issue here or on another thread. I am beginning to doubt that isolation is possible. When a particle is created, how can it be isolated from the environment? If it cannot be isolated, if it's never really isolated, the decoherence model fails to establish anything. 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/ea4c9893-804e-4882-a65c-ae44893c699b%40googlegroups.com.
