> On 20 Apr 2018, at 01:08, Bruce Kellett <bhkell...@optusnet.com.au> wrote:
>
> From: Bruno Marchal <marc...@ulb.ac.be <mailto:marc...@ulb.ac.be>>
>>> On 18 Apr 2018, at 15:11, Bruce Kellett <
>>> <mailto:bhkell...@optusnet.com.au>bhkell...@optusnet.com.au
>>> <mailto:bhkell...@optusnet.com.au>> wrote:
>>>
>>> From: Bruno Marchal <marc...@ulb.ac.be <mailto:marc...@ulb.ac.be>>
>>>>> On 17 Apr 2018, at 00:58, Bruce Kellett <
>>>>> <mailto:bhkell...@optusnet.com.au>bhkell...@optusnet.com.au
>>>>> <mailto:bhkell...@optusnet.com.au>> wrote:
>>>>>
>>>>> From: Brent Meeker < <mailto:meeke...@verizon.net>meeke...@verizon.net
>>>>> <mailto:meeke...@verizon.net>>
>>>>>> On 4/15/2018 8:33 PM, Bruce Kellett wrote:
>>>>>>>> We have discussed this, and I have never agree with this. The singlet
>>>>>>>> state (in classical non GR QM) describes at all times an infinity of
>>>>>>>> combinations of experimental result.
>>>>>>>
>>>>>>> This is false. Even in Everettian QM there are only two possible
>>>>>>> outcomes for each spin measurement: this leads to two distinct worlds
>>>>>>> for each particle of the pair. Hence only 4 possible parallel
>>>>>>> universes. Where do you get the idea that there are infinitely many
>>>>>>> parallel universes? This is not part of Everettian QM, or any other
>>>>>>> model of QM. But even if you can manufacture an infinity of universes,
>>>>>>> you still have not shown how this removes the non-locality inherent in
>>>>>>> the quantum formalism.
>>>>>>
>>>>>> Bruno's ontology is all possible computations, so he's already assumed
>>>>>> (countably) infinite worlds. When there are only four or two outcomes
>>>>>> of an experiment it just means his worlds are divided into four or two
>>>>>> equivalent subsets.
>>>>>
>>>>> That might very well be the case. But then that has absolutely nothing to
>>>>> do with Everett or quantum mechanics. Bruno's long-held claim is that
>>>>> Everett's many worlds obviate the need for non-locality. But he has never
>>>>> been able to produce a coherent argument to this effect. It is always
>>>>> this bullshit about an infinite number of worlds -- as if that made any
>>>>> difference at all.
>>>>
>>>> You are the one making the extra-ordinary claims. I don’t say much more
>>>> than maudlin on this issue in his book on Nonon-Locality: it makes no
>>>> sense in the many-world.
>>>
>>> You seriously misrepresent Maudlin. To make this as clear as possible, I
>>> have taken the third edition (2011) of Maudlin's book "Quantum Non-Locality
>>> and Relativity" and typed out all the sections under the heading of
>>> "many-worlds theory" from the index.
>>>
>>>
>>> "The many-worlds theory is incoherent for reasons which have been often
>>> pointed out: since there are no frequencies in the theory there is nothing
>>> for the numerical predictions of quantum theory to mean." (Page 4, Note 1.)
>>>
>>> "So we must either abandon locality or abandon the predictions of quantum
>>> theory for events at space-like separation. I have sketched how some
>>> versions of the many-worlds interpretation of quantum theory appear to do
>>> the latter, and considered in some detail how locality might be abandoned
>>> in a technically precise way." (Page 224, Chapter 10)
>>>
>>> "Other, more popular approaches, though, are taken quite seriously even
>>> though they offer no clear account of local beables at all. Most obviously,
>>> many-worlds theorists typically do not postulate any local ontology in the
>>> foundations of the theory: all there is is the wave-function. A lot of
>>> attention is paid to "observables" and "decoherence", but it is not at all
>>> clear how to generate a local ontology if all one has to work with is the
>>> wave-function. ... But since the wave-function is not itself a local
>>> beable, nothing about its dynamics can yield a local ontology." (Page 250.)
>>>
>>>
>>> Then the most extensive discussion of many-worlds appears in Chapter 10,
>>> which was new for the third edition of his book.
>>>
>>> "Standard quantum theory asserts that measurements always have outcomes,
>>> and furthermore have unique (albeit unpredictable) outcomes. It is exactly
>>> because such experiments always have outcomes that we can ask after the
>>> predictions of the theory for the correlations between the outcomes: if I
>>> measure the polarization of a photon in some direction on one wing of an
>>> experiment and the polarization of an entangled photon on the other wing,
>>> how like is it that the polarization outcomes will be the same (both passed
>>> or both absorbed) or different (one passed and the other absorbed)?
>>>
>>> "If a many-worlds interpretation insists that there are no local beables,
>>> then this is the situation. It cannot possibly reproduce the predictions of
>>> standard quantum theory about the outcome of experiments, and so is not
>>> relevant to our discussion of theories that agree with these predictions.
>>> But the many-worlds interpretation is never presented in this way. It is
>>> rather presented as if instead of no local beables, there is a (largely
>>> invisible) profusion of them. That is, instead of nothing happening on
>>> either wing of the experiment, the standard story is that everything
>>> happens on both wings: on both wings, there is "a world" in which the
>>> photon passes its polarizer and "a world" in which it is absorbed, no
>>> matter how the polarizers were oriented.
>>>
>>> "... If the wave-function never collapses, then the matter density evolves
>>> into a rather indistinct blob, consisting in all the "possible" outcomes of
>>> the experiment (passed and absorbed, for example, with all these results
>>> being recorded in macroscopic ways) literally superposed on one another in
>>> the same space-time region. One then tries to argue that different
>>> components of the blob are causally disconnected from one another, and so
>>> would be mutually transparent: many outcomes co-existing but unaware of
>>> each other. One will typically appeal to decoherence of the wave-function
>>> and a functional analysis of how to separate the blob into distinct worlds
>>> to make out this conclusion.
>>>
>>> "But two facts must be kept in mind. First, as we have seen, the matter
>>> density ontology is not implied by the existence of the wave-function per
>>> se. ... If a many-worldser wants there to be a local matter density in
>>> space-time, then that has to be postulated in addition to the
>>> wave-function. Second, if we produce an account like this, then there still
>>> has to be discussion of what it means to say that the outcomes on the two
>>> wings of the experiment are correlated to some degree. If whenever a
>>> polarization experiment is done, with any orientation of the polarizers,
>>> both outcomes are always produced, then it is not obvious what it might
>>> mean to say that these outcomes are correlated. If no sense can be made,
>>> then again the theory does not reproduce the predictions of standard
>>> quantum theory, which predicts definite correlations for outcomes at
>>> space-like separation. And if some sense can be made of the existence of
>>> correlations, we have to understand how. In particular, if appeal is made
>>> to the wave-function to explicate the sense in which, say, the "passed"
>>> outcome on the right is paired with the "absorbed" outcome on the left to
>>> form a single "world", then we have to recognize that this is not a *local*
>>> account of the correlations since the wave-function is not a local object."
>>> (Pages 250-252.)
>>>
>>>
>>> So Maudlin does not support your notion that many-worlds removes the need
>>> for non-locality. In fact, Maudlin is clearly claiming the exact opposite.
>>> He clearly does not like the many-worlds approach, calling it incoherent.
>>> But even if sense can be made of such a theory, there is still no
>>> possibility of a *local* account of the correlations in polarization
>>> measurements of the entangled singlet state.
>>>
>>
>>
>> I have only the first edition. His “critics” on Everett comes from his
>> missing of the first-person indeterminacy (he choose “materialism” against
>> mechanism!): he does not look at each diaries of the observer of the
>> Schroedinger cat.
>
> The 'diaries' you put so much store on add absolutely nothing.
What? This means you have not even read Everett. Or that you repeat something.
I could use personal memories, but the diary makes clear it is 3p sharable,
even if it is in term of the wave or the description from outside. Obviously it
is the key notion, and Maudlin missed it, in both his paper on the
computationalist mind-body problem, and in books of inseparability (which are
both excellent). That is why he uses many-minds, insisted of many-worlds, but
in all case (QM and mechanism) we know that it is something close to many
histories.
>
>> So, indeed, he needs the “many-mind” theory to give sense to Everett, where,
>> at least im my edition he made clear that the “non locality” does not apply.
>> I quote ”Since there are no *relevant* correlation between space-like
>> separated event [in the many-mind theory] there is no problem of
>> non-locality.
>
> "Many-minds" theory is not many-worlds theory, nor has it any connection with
> Everett. Actually, I think Maudlin is too charitable towards many-minds. As
> he points out in edition 3 in his extended discussion of many-worlds, he says:
>
> "In particular, if appeal is made to the wave-function to explicate the sense
> in which, say, the "passed" outcome on the right is paired with the
> "absorbed" outcome on the left to form a single "world", then we have to
> recognize that this is not a *local* account of the correlations since the
> wave-function is not a local object.”
See Saibal Mitra concise answer to this.
>
> That is precisely what the many-minds interpretation does. It claims that
> there is no non-locality because minds (separated from events) are not
> space-like separated. But that relies on the wave-function, which is itself
> intrinsically non-local.
In that sense, arithmetic is non-local. But you were saying that there are
physical action at a distance, in one world, but publish a paper on this if you
really believe this.
In the mind-body problem, this discussion is on the fringe of the “1004 error”
as we have not yet even a coherent notion of space, nor even of two qubits.
>
>
>> As digital mechanism is of the “many-mind” type at the phenomenological
>> outset, all problems that some Everettian can have is due to the
>> Aristotelian assumption, which is inconsistent with computationalism in
>> cognitive science from the start (as I showed).
>
> Digital mechanism ("comp") is not even closely related to QM and Everett,
This shows you have not read my papers. Nor Everett who used computationalist
more or less explicitly. Indeed, that is why his work is not finished: we have
to justify the wave phenomenologically.
> so this does not eliminate non-locality in an Everettian approach to quantum
> theory.
>
>
>> Maudlin’s conclusion: “Or finally, one can both avoid collapses and retain
>> locality by embracing the Many-Minds ontology, exacting a rather high price
>> from common sense”.
>
> I think the fact that he sees "many-minds" as "exacting a rather high price
> on common sense" expresses Maudlin's opinion of this approach fairly clearly
> -- he considers it to be a load of horseshit. And that is generally the
> opinion of the wider scientific community. Many-minds has never gained any
> traction because it is just too contrived, too baroque. Maudlin's final
> comment on "many-minds" is also quite telling:
>
> "Even more radically, one could adopt the many-minds theory and deny that
> there are any violations of Bell's inequality by events at space-like
> separation: the relevant correlations exist only in individual minds. All of
> these options become yet more bizarre when one shifts from Special to General
> Relativity." (Page 222.)
>
> And:
> "If the world we experience is only in our mind why does the postulation of
> mind-independent determinate physical states work so well?" (Page 222.)
That are good question, and the answer is what I explain here. That it is
counterintuitive means only that it hurts the Aristotelian belief, based on the
harassment of the skeptical for a very long period. Appeal to common sense are
not valid in science.
>
> It is interesting that Maudlin, in a book of nearly 300 pages on Quantum
> Non-Locality, has devoted only a couple of pages to "many-worlds", and less
> than one page to "many-minds". This indicates better than anything else what
> he really though of these ideas as resolutions of the non-locality problem.
It explains why he missed the solution. That was easy to predict, as he showed
in 1989 the result I published also in 1988, i.e. that mechanism and
materialism are incompatible, but it makes clear that he favours Materialism.
But then, he does not seem to know Church thesis, which has completely change
the conception of the notion of finite and infinite since, and we know that
machines are not that simple to study.
>
>> For this Plato did warn us, and indeed computationalism leads to that same
>> form of price. Note that with comp the “many-minds” is stilll only in the
>> phenomenology. The ontology is given by any Turing universal machinery
>> (combinators, numbers, …). Of course “counter-intuitive” is not a refutation.
>
> What "comp" says or does not say is irrelevant to this discussion.
Quite the contrary, and that should be obvious if you took the care to try to
understand the papers instead of invoking your metaphysical a priori.
Bruno
>
> Bruce
>
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