On Tue, Jul 30, 2019 at 6:32 AM Jason Resch <[email protected]> wrote:
> On Mon, Jul 29, 2019 at 6:41 AM Bruce Kellett <[email protected]> > wrote: > >> On Mon, Jul 29, 2019 at 8:43 PM Jason Resch <[email protected]> wrote: >> >>> On Fri, Jul 26, 2019 at 6:29 PM Bruce Kellett <[email protected]> >>> wrote: >>> >>>> On Sat, Jul 27, 2019 at 8:44 AM Jason Resch <[email protected]> >>>> wrote: >>>> >>>>> On Fri, Jul 26, 2019 at 2:24 AM Bruce Kellett <[email protected]> >>>>> wrote: >>>>> >>>>>> >>>>>> MWI is irrelevant to this discussion, since the branches in MWI are >>>>>> completely disjoint and form separate coherent worlds. Without overlap, >>>>>> common sense notions of personal identity continue unchanged in all >>>>>> branches separately. >>>>>> >>>>> >>>>> Can we really ignore the global view? >>>>> >>>> >>>> Yes, we have no evidence that such a view exits or even makes any sense. >>>> >>> >>> Why doesn't it? >>> >> >> Because there is no "view from outside" as it were. >> > > But this is exactly the situation for Wigner's friend, or when we use a > quantum computer. > The trouble is that Wigner's friend, or the cat for that matter, is a classical, decohered, concept. So there are no quantum superpositions involved. The fact that you can write the situation for Wigner's friend in the form of a superposition does not mean that it actually is one. One cannot interfere the different components. It would also be the case for any being in another universe choosing to > analyze ours using the power of simulation. Do you not believe in an > objective reality? > Objective reality is that obtained by intersubjective agreement. By this token, the "global wave function" has no objective existence. We speak of a superposition of a wave function whenever we speak of a >>> system separated from an external environment. Can we not view the whole >>> universe this way? Feynman and Everett thought we could, and Wheeler >>> thought so on Tuesdays. >>> >> >> Argument from authority is no argument in this case, because it makes no >> sense to view the whole universe in this way. There is no "person" who sees >> the global wave function. >> > > Nor is there any person who sees beyond the horizon of a black hole. But > we can use our best theories to describe that is happening there. Why > can't we do the same for the global view? > Poor analogy. We can readily see what is beyond the horizon of a black hole -- just jump in and look. We can't do anything to obtain your required "global view" because we are restricted to having only "relative state" views, even with Everett. According to Everettt, persons and quantum phenomena are relative to >> particular branches of the wave function. >> > > Is there a wave function for the universe as a whole? > Who knows. I find the concept somewhat dubious -- over-enthusiastic extrapolation from simple laboratory experiments. What if we want to consider cases like Wigner's friend? Or cases where we >>>>> emulate brains in quantum computers? >>>>> >>>> >>>> What about such cases? Despite David Deutsch, these do not prove the >>>> truth of MWI. >>>> >>> >>> No but it casts significant doubt on the single world view, which cannot >>> account for them. >>> >> >> The single world view can account for these easily, so such cases provide >> no evidence for MWI. >> > > Where do the 10^1000 intermediate computational states occur in the > single universe view of a quantum computer factoring a big semiprime number? > Quantum computers work by interference of quits, and such interference can only take place in one world -- different worlds are orthogonal. The fact that one can analyse a quantum computer in a particular basis which can be represented as a series of parallel computations does not mean that this is actually what happens. Heuristic constructs seldom correspond to reality. > Superpositions exist in a single world. If we form multiple worlds via >>>> decoherence, then the worlds are, by definition, orthogonal, so there is no >>>> possibility of their ever recombining. David Deutsch got this wrong many >>>> times. Quantum computers work by interference of qbits -- so they must all >>>> exist in the same world. A conscious quantum computer does not experience >>>> other worlds. >>>> >>> >>> If you fed in as input, qubits prepared to be in a superposition using >>> Hadamard gate, then the conscious mind would experience many states, >>> simultaneously. >>> >> >> Demonstrate that by actually doing it. >> > > I described the process. We lack the technology to do this today, but it > is exactly what our current theories suggest would happen. > Suggestions are not reality, and I doubt that the theories do actually suggest this. > Scott Aaronson, an expert in quantum computing agreed that if the computer > program is conscious, then one so-prepared on a quantum computer would > realize multiple conscious states simultaneously. > Argument from authority. Scott Aronson can provide no more evidence for this that you can. > Can you show any flaw in the reasoning? > Consciousness is a classical phenomenon and as such cannot participate in a true quantum superposition. The fact that anything done by a quantum computer can also be done by a classical Turing machine proves this beyond any doubt: you cannot have superpositions in a classical machine. You can simulate them, but then a simulation of a rain storm does not make you wet. Bruce Now this is in the context of a quantum computer that remains isolated >>> from its external environment. >>> >>> Now what happens when you consider that we too are isolated from our >>> external environment? Are we not in the same situation as this >>> hypothetical conscious observer simulated on a quantum computer? >>> >> >> No. A quantum computer cannot do anything that is not also doable (albeit >> more slowly) on a classical Turing machine. >> > > Correct. > > >> So quantum computers do not put simulated minds into superpositions. >> >> > Quantum computers operate on qubits that are in a state of superposition. > Using N such randomly initialized qubits is analogous to running 2^N Turing > Machines, each prepared in one of the unique 2^N possible values of an > N-bit string. > > So you are correct that the quantum computer isn't doing anything that > Turing machine cannot do more slowly. But I don't see how this is an > argument against my point. The observer running on the quantum computer > would experience "many worlds". > > Jason > -- 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/CAFxXSLTCcewk4K5ui6TDYVfStXSTUSt0Lw38WBSD-PMTPe9Yuw%40mail.gmail.com.
