On Friday, November 24, 2017 at 12:15:46 PM UTC-7, Bruno Marchal wrote:
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>
> On 22 Nov 2017, at 22:51, [email protected] <javascript:> wrote:
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>
>
> On Wednesday, November 22, 2017 at 5:24:48 PM UTC, Bruno Marchal wrote:
>>
>>
>> On 22 Nov 2017, at 09:55, [email protected] wrote:
>>
>>
>>
>> On Tuesday, November 21, 2017 at 12:43:05 PM UTC-7, Bruno Marchal wrote:
>>>
>>>
>>> On 20 Nov 2017, at 20:40, [email protected] wrote:
>>>
>>>
>>>
>>> On Monday, November 20, 2017 at 6:56:52 AM UTC-7, Bruno Marchal wrote:
>>>>
>>>>
>>>> On 18 Nov 2017, at 21:32, [email protected] wrote:
>>>>
>>>>
>>>>
>>>> On Saturday, November 18, 2017 at 1:17:25 PM UTC-7, Brent wrote:
>>>>>
>>>>>
>>>>>
>>>>> On 11/18/2017 8:58 AM, John Clark wrote:
>>>>>
>>>>> * > I think "must" is unwarranted, certainly in the case of the
>>>>>> MWI. Rather, it ASSUMES all possible measurements must be realized in
>>>>>> some
>>>>>> world. **I see no reason for this assumption other than an
>>>>>> insistence to fully reify the wf in order to avoid "collapse".*
>>>>>>
>>>>>
>>>>> The MWI people don't have to assume anything because
>>>>> there is absolutely nothing in t
>>>>> he Schrodinger
>>>>> Wave E
>>>>> quation
>>>>> about collapsing, its the Copenhagen people who have to assume that
>>>>> somehow it does.
>>>>>
>>>>>
>>>>> It's not just an assumption. It's an observation. The SE alone
>>>>> didn't explain the observation, hence the additional ideas.
>>>>>
>>>>> Brent
>>>>>
>>>>
>>>> *Moreover, MWI DOES make additional assumptions, as its name indicates,
>>>> based on the assumption that all possible measurements MUST be measured,
>>>> in
>>>> this case in other worlds. *
>>>>
>>>>
>>>> That is not an assumption. It is the quasi-literal reading of the
>>>> waves. It is Copenhagen who added an assumption, basically the assumption
>>>> that the wave does not apply to the observer: they assumed QM was wrong
>>>> for
>>>> the macroscopic world (Bohr) or for the conscious mind (Wigner, von
>>>> Neumann) depending where you put the cut.
>>>>
>>>
>>> *CMIIAW, but I see it, the postulates tell us the possible results of
>>> measurements. They don't assert that every possible measurement will be
>>> realized.*
>>>
>>> What do you mean by realize?
>>>
>>
>> *Realized = Measured. AG*
>>
>>
>>
>> Measured by who?
>>
>
> Doesn't this same question come up in MWI, and with Many Worlds the
> problem seems to metastasize. AG
>
>
>> More precisely, if Alice look at a particle is state up+down: the wave is
>> A(up + down) = A up + A down. Then A looks at the particles. The waves
>> evolves into A-saw-up up + A-saw-down down. Are you OK to say that a
>> measurement has occurred? Copenhagen says that the measurement gives
>> either A-saw-up up or A-saw-up down, but that NEVER occurs once we abandon
>> the collapse. So without collapse, a measurement is a first person
>> experience. In this case, it is arguably the same as the experience of
>> being duplicated.
>>
>
> If you could revise your reply using the wf of the singlet state (without
> the normalizing factor) in the following form, I might be able to evaluate
> your analysis; namely, ( |UP>|DN> - |DN>|UP> ). For example, I am not clear
> how you apply linearly.Does each term in the sum represent a tensor
> product? TIA AG
>
>
> I was just explaining that a measurement is any memorable interaction,
> which is simplest to illustrate with a tensor product of Alice (|A>)and a
> simple superposition. In your notation: |A> (|UP> + |DN>) = |A> |UP> + |A>
> |DN> .
>
*Before the measurement Alice is NOT entangled with the entangled pair
since it is isolated; nor afterward since the system being measured is now
NOT in a superposition of states. So your tensor addition is based on
fallacies, which I infer permeates your general analysis of this situation.
BTW, please see my last post where I raised additional issues. TY, AG*
>
> In the case of the singlet state, it is more subtle, as |UP>|DN> -
> |DN>|UP> describes a many-worlds with Alice having a spin in any direction,
> and Bob, too but the opposite relatively to each others (the notation is
> misleading). We must keep in mind the rotational invariance of the spin. So
> we the Alice Bob situation is more intricate and tedious to describe.
> Sometimes I referred to the simple account of this in the Everett FAQ by
> Michael Clive Price, but it seems not available since some times. We have
> copied the relevant details in previous discussions though, so you might
> try to find it in the archives with the key word "Michael", or something. I
> have unfortunately not the time "here and now". Later perhaps. With
> Everett, it is important to reason independently of the bases in between
> the measurements.
>
> I guess you see that violation of the BI leads to "action at a distance"
> if we assume a collapse, or a mono-world theory. I don't see Bell'
> argument applying in the MW context, though.
>
> Bruno
>
>
>
>
>> Without collapse, the measurement are described by the quantum laws.
>>>
>>
>> *That's precisely what QM doesn't describe, which constitutes part of the
>> measurement problem. AG*
>>
>>
>> Just see above. QM describes precisely why the observers believe
>> correctly (with respect to their first person notion) having done
>> measurement, and got precise outcomes, but from the 3p waves perspectives,
>> all we have is a structured collection of relative states (which all exists
>> and are structured in arithmetic, BTW).
>>
>>
>>
>>
>> An observer along a superposition up + down, *is* the same state as the
>>> observer along up superposed with the observer down, if he look in the {up
>>> + down, up - down} basis, "he" will see he is in up+down, but if he looks
>>> in the {up down} basis; the observer consciousness differentiate, in his
>>> first person perspective, but the solution of the wave describes the two
>>> outcomes realized from the point of view of each observer. You can't decide
>>> to make one of them into a zombie.
>>>
>>
>> *I have no idea what you mean. Please try again. AG*
>>
>>
>> The tensor product is linear, so A(up + down) = (A up) + (A down). OK?
>>
>> the evolution is linear and when A looks at the particle: she is
>> described by (A-up up) + (A-down down). (with of course 1/sqrt(2)
>> everywhere).
>>
>> the consciousness of A has differentiated into (A-up) and (A-down). With
>> Bohr, one among A-up and A-down mysteriously disappears. With Bohm (one
>> world + a potential simulating the entire Many-world, but "without
>> particles") one among A-up and A-down becomes a zombie, even one lacking a
>> body made of particles, yet, the waves describes them as being alive like
>> you and me, and we can test it (in principle) by making quantum computation
>> with oneself.
>>
>>
>>
>>
>>
>> *So I see an additional assumption in the MWI. AG*
>>>
>>> I disagree, and Everett would disagree. I am aware most people claims
>>> Everett and Copenhagen are differet intepretations, but from a
>>> metamathematical obvious view: Everett and Copenhagen are different
>>> theories.
>>>
>>
>> *They have identical postulates but Everett adds another non-trivial one
>> as I indicated above; namely, that every possible measurement is realized,
>> that is measured, in another world. I don't see why you insist on denying
>> something so obvious. AG*
>>
>>
>>
>> ?
>>
>> I think you should read Everett. he propose a new formulation of QM, and
>> it is copenhagen with the withdrawal of the collapse postulate.
>>
>> All measurement are realized in the sense that no superposition ever
>> collapse, but that it looks in that way from the first person perspective
>> of the observer. he reduces the quantum indeterminacy to the classical
>> self-indetermination based on amoeba-like duplication. The only problem is
>> that his task is not finished: by using mechanism (as he recognizes
>> explicitly in his long text) he must take into account all computations,
>> not just the quantum one. in other word, the wave itself must be recovered,
>> and indeed the math indicates that is possible, as quantum logics appears
>> at the place where such task must be handled.
>>
>>
>>
>>
>>
>>
>>
>>> Everett is the SWE, and Copenhagen is SWE + collapse. We might accept
>>> that Everett theory has not yet justify all aspects of what could be the
>>> physical reality (and provably so if we assume digital mechanism in
>>> cognitive science), but, to be short, it is less crazy than any theory
>>> making the collapse into a physical phenomenon.
>>>
>>
>> *Why crazy? What we seem to observe IS collapse;*
>>
>>
>> yes. but that is the whole difference between a platonist and an
>> aristotelian. The aristotelian define reality by what they see. The
>> platonist define reality by whatever makes us to believe that we see
>> something.
>>
>> And we do not observe a collapse/ We observe a cat, or something. Exactly
>> like the wave without collapse, + a mechanist theory of mind, predicts.
>>
>> Everett just soleved the mind-body problem, at the conceptual level. And
>> partially, because my contribution here is that this *has to be*
>> prolongated in arithmetic, and the wave must be justified itself by a
>> statistic on all computations. It works at the proposition level: it gives
>> quantum logic at the place of propositional physics.
>>
>>
>>
>>
>>
>> * that is, all probabilities evolving to zero except the measured
>> probability evolving to 1, by an as-yet unknown physical process. AG *
>>
>>
>> A unknown physical phenomenon that Einstein criticized already in 1927,
>> by showing that the collapse would need to be non covariant. The wave has
>> to vanish instantaneously. With the many-worlds, there is no problem at all
>> for the easy 1927 thought experience: the wave never vanishes, but you
>> localize yourself on which branch you are in the superposition.
>>
>> The measurement problem exists only when we associate a unique outcome
>> for the experiment. With Everett, measurement are explained by
>> interaction+entanglement. decoherence then explains why we can't see the
>> "other branches".
>>
>> I know that Bruce and Clark disagree, but in my opinion, Everett
>> (non-collapse) solves all the conceptual problems that Einstein disliked so
>> much in QM. We get a reversible deterministic local physical "big picture".
>>
>> Now, with mechanism, this leads to no universe at all, in the
>> aristotelian sense of the words, as the "physical universe", the wavy
>> multiverse of Everett-Deutsch, has to be itself the winner in a deeper game
>> played by all computations (which exists in elementary arithmetic). "All
>> computations" is a very solid notions, thanks to Gödel's theorem which
>> protects Church's thesis and Mechanism from a vast collection of
>> reductionist philosophy.
>>
>> Bruno
>>
>>
>>
>>
>>
>> *I reject this hypothesis. What I do concede is that in the case of the
>>>> Multiverse of String Theory, if time is infinite and the possible
>>>> universes
>>>> finite -- 10^500 -- all possible universes will be, or have been,
>>>> realized.
>>>> AG*
>>>>
>>>>
>>>> OK, but that is not Everett-Deustch "multiverse" (relative state,
>>>> many-worlds, etc.).
>>>>
>>>
>>> *Too much parsing! I was trying to explain that the Multiverse of String
>>> Theory is manifestly *different* from the Many Worlds of the MWI. AG *
>>>
>>>
>>> Yes. you are right on this. In string theory with collapse (if this
>>> could even make sense), you have 10^500 physical realities. In string
>>> theory without collapse, you have (10^500 * Infinity) physical realities,
>>> at first sight (with mechanism they are just "coherent dreams" (sigma_1
>>> true sentences seen in the Bp & ~Bf mode) by Numbers).
>>>
>>> Bruno
>>>
>>>
>>>
>>>
>>>
>>>> Bruno
>>>>
>>>
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>>> http://iridia.ulb.ac.be/~marchal/
>>>
>>>
>>>
>>>
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>> http://iridia.ulb.ac.be/~marchal/
>>
>>
>>
>>
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