Re: Radioactive Decay States

[agrayson2000]

On Sunday, July 15, 2018 at 7:48:02 AM UTC-6, scerir wrote:
>
> ---  SCERIR;  IN YOU OWN WORDS; WHAT DO YOU BELIEVE AND WHY? AG
>
> Is the state ψ (i.e. a superposition state) a physically object or is it 
> an abstract entity that merely provides information about the system?
>

*We know for sure it's a calculational tool. What's the argument it's 
anything beyond that? AG*
 

> This is the question.
>
> This mystery is the fact that no physical property is, in general, a 
> possessed property unless it is measured.
>
>
>
>

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Re: Radioactive Decay States

[agrayson2000]

On Sunday, July 15, 2018 at 7:48:02 AM UTC-6, scerir wrote:
>
> ---  SCERIR;  IN YOU OWN WORDS; WHAT DO YOU BELIEVE AND WHY? AG
>
> Is the state ψ (i.e. a superposition state) a physically object or is it 
> an abstract entity that merely provides information about the system?
>

*It just gives information. As I have repeatedly stated, there is no unique 
basis for expressing a superposition. So if you want to claim the system is 
in all component states simultaneously, you need to justify it. No one 
seems up to the challenge. They seem to have fallen in love with 
complacency. IMO, the error arose due to the double slit experiment. Here, 
if the particle moves as a wave, it goes through both slits, and there is 
mutual interference. Hence, in this seminal experiment, one can imagine 
that the system before measurement is simultaneously in the *two* states of 
the superposition. But I think happened, historically, is that this case 
was generalized inappropriately. E.g., what is the interference between 
Decayed and Undecayed states of a radioactive source? Can you specify it? 
AG*
 

> This is the question.
>
> This mystery is the fact that no physical property is, in general, a 
> possessed property unless it is measured.
>

*I can't explain everything. I can only demand a rigorous explanation for 
the assumption that a system in a superposition of states, is in all 
component states simultaneously, notwithstanding the NON UNIQUENESS of 
bases. So far, I don't see any foundation for this assumption, and when I 
reject it, many of the quantum paradoxes evaporate. AG *

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Re: Radioactive Decay States

[agrayson2000]

On Monday, July 16, 2018 at 8:30:58 AM UTC-6, Bruno Marchal wrote:
>
>
> On 13 Jul 2018, at 01:55, agrays...@gmail.com  wrote:
>
>
>
> On Wednesday, July 11, 2018 at 2:16:24 PM UTC-6, agrays...@gmail.com 
> wrote:
>>
>>
>>
>> On Tuesday, July 10, 2018 at 4:42:44 PM UTC-6, Brent wrote:
>>>
>>>
>>>
>>> On 7/10/2018 3:01 PM, agrays...@gmail.com wrote:
>>>
>>> *IIRC, the above quote is also in the Wiki article. It's not a coherent 
>>> argument; not even an argument but an ASSERTION. Let's raise the level of 
>>> discourse. It says we always get a or b, no intermediate result when the 
>>> system is in a superposition of states A and B.. Nothing new here. Key 
>>> question: why does this imply the system is in states A and B 
>>> SIMULTANEOUSLY before the measurement? AG  *
>>>
>>>
>>> Because, in theory and in some cases in practice, there is a direct 
>>> measurement of the superposition state, call it C, such that you can 
>>> directly measure C and always get c, but when you have measured and 
>>> confirmed the system is in state c and then you measure A/B you get a or b 
>>> at random.   The easiest example is SG measurements of sliver atom spin 
>>> orientation where spin UP can be measured left/right and get a LEFT or a 
>>> RIGHT at random, but it can be measured up/down and you always get UP.  Any 
>>> particular  orientation can be *written* as a superposition of two 
>>> orthogonal states.  
>>>
>>
>> *When you're trying to explain esoteric issues to a moron in physics, you 
>> need to be more explicit. These are the issues that cause confusion and 
>> caused me to fail to "get it". After some subsequent posts, you seem to be 
>> saying that in an SG spin experiment where the measurement base is UP/DN, 
>> the system being measured is ALSO in a superposed LEFT/RIGHT state which is 
>> also measured (by an SG device designed to measure spin?), and that the 
>> LEFT/RIGHT superposed state persists with some persistent eigenvalue after 
>> UP/DN is measured. It's murky for us morons.  How does one get the system 
>> to be measured in a superposition of RIGHT/LEFT; what is the operator for 
>> which that superposition is an eigenstate, and what is the value of the 
>> persistent eigenvalue?*
>>
>> *Furthermore, you finally assert that since the RIGHT/LEFT state persists 
>> -- meaning that particle is in some DEFINITE state after the spin is 
>> measured -- and since (as you finally, finally assert) that that state can 
>> be written as a superposition of UP/DN, all is well -- in the sense that we 
>> can now be certain that the system is physically and simultaneously in the 
>> UP and DN states (which I am claiming is a fallacy). *
>>
>> *HOWEVER, assuming that I understand your argument after filing the gaps 
>> in your presentation (and pointing to some unanswered issues), I now must 
>> "rant" again that the UP/DN superposed representation is NOT unique. Thus, 
>> since there are finitely many or uncountable many such representations, and 
>> since (as per LC) QM has no preferred basis, your argument for the physical 
>> simultaneity of UP and DN states fails. I mean, I could write the 
>> superposed states in the basis (UP + DN) and (UP - DN), or in many other 
>> bases. Absent uniqueness of bases, one cannot assert that the system is 
>> physically and simultaneously in any particular pair of basis vectors.*
>>
>> *AG*
>>
>
> *I've been looking over your references to Peres. CMIIAW, but AFAICT he 
> doesn't deal with the issue I have been "ranting" about; namely, the 
> non-uniqueness of bases, implying IMO that the concept of simultaneous 
> physical states of the components of a superposition is an additional, 
> unsupported assumption of QM which leads to some popular misconceptions of 
> what QM is telling us. *
>
>
>
> Then you need to find a new explanation of the interference that occurs in 
> basically all quantum experiments, like the two slits, the statistics of 
> results with Stern-Gerlach spin measuring apparatus, etc.
>

*I am not trying to explain the interference. Rather I am pointing out an 
unnecessary assumption that leads to paradoxes. See comment below. AG*
 

> The whole point of the physical wave amplitudes is that the diverse 
> superposed components have a physical role, through destructive or 
> constructive, or in between, interference.
>

*The amplitudes give probabilities of occurrence, confirmed by 
measurements. Nothing more. You forget that the components of the 
superposition are usually assumed to be orthogonal states, which don't 
mutually interfere. Thus, you are claiming to explain interference from 
component states which don't interfere. Try this; in the case of 
radioactive decay, can you define the interference between Decayed and 
Undecayed states? AG*
 

> Note that the discussion here supposed the quantum theory, but you are 
> free of course to propose an alternative. Many have tried without success, 
> though.
>

*What I am doing is asking the usual 

Re: Bootstrapping Reality: The inconsistency of nothing

[Brent Meeker]

On 7/16/2018 8:18 AM, Bruno Marchal wrote:


I would like to think that this were the case, but you keep coming up 
with irrelevancies that contradict the straightforward account of 
these phenomena. If you forget about the metaphysics and just 
concentrate on Alice and Bob making real measurements and recording 
them in their lab books, then all these superfluities vanish. There 
are no counterfactuals, no worries with other unobserved worlds, and 
Bell's theorem goes through exactly as he intended. Many-worlds does 
not invalidate Bell's argument. In fact, deflecting Bell's theorem 
would do no more than allow for the possibility of a local hidden 
variable account. That alone does not prove that many-worlds is local 
-- that would still have to be established by developing such a local 
hidden variable theory. No one has to date developed such a theory. 
But since Bell's theorem has not been deflected, we do not have to 
worry about such contingencies.



So we really agree. You have been probably misguided when trying to 
defend John Clark who claimed that there are still FTL influence in 
Everett, when the Bell’s inequality relations implies FTL only when we 
assume unique outcomes of the experiences (i.e. some collapse, or 
Bohm’s type of hidden variable).


No need of patronizing remark either, especially when rephrasing what 
I was just saying. If you agree that there is no FTL in the 
many-worlds, we do agree, that was the point I was making to J. Clark. 
Not sure why you defended it, especially that you have shown 
implicitly that you have no problem with the step 3 of the Universal 
Dovetailer Paradox. You might eventually understand that with 
mechanism, Everett’s task is still incomplete, as we need to justify 
the wave from all computations, as seen from some self-referential 
modes (fortunately and constantly implied by incompleteness).


Not to reignite the argument, but it originated because Bruno claimed 
that MWI does away with non-locality in QM.


Brent

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Re: Do we live within a Diophantine equation?

[John Clark]

On Sat, Jul 14, 2018 at 2:23 PM, Jason Resch  wrote:


> *​>​Suppose Abby the guinea pig wants to travel long distance, say from
> Earth to Mars. On Earth she enters the scanner which scans her body and
> brain cells in great detail at an instant of time, down to all molecular
> details that are functionally relevant. At the same time, her body is
> instantly destroyed, and the scanned data is sent to the replicator station
> located at the journey’s target. There, the replicator instantly builds a
> perfect copy of Abby’s body and brain, based on the transmitted
> data​. Clearly the material body is destroyed (and rebuilt) in this
> process, which leads to instant feelings of unease to most guinea pigs or
> humans who think about this scenario.*
>

There would be no logical reason for you being uneasy about this and there
wouldn't even be a illogical reason for being uneasy unless somebody told
you about the destruction and reconstruction of your body, and even then
you probably wouldn't believe them because subjectively you would feel no
different whatsoever. Our ancestors would be terrified at getting into an
aluminum tube and flying 40,000 feet up in the air at 600 mph, but if the
weather was calm they wouldn't even know they were doing so unless they
looked out the window.


> *​>​a malfunction disturbs the daily routine: a malicious admirer of Abby
> hacks into the transmitter’s computer system and causes the teleporter to
> create two perfectly identical copies of Abby at exactly the same local
> time on Mars, next to each other. How does Abby experience this situation? *
>

Abby #1 finds herself on Mars as usual but notices somebody who looks just
like her standing to her right.  Abby #2 finds herself on Mars as usual but
notices somebody who looks just like her standing to her left. Looking
backward through time neither remembers experiencing any branching,
everything will seem perfectly continuous to both. Looking forward through
time neither remembers any branching, and in fact neither remembers
anything at all because we can remember the past but not the future, so the
future can not tell Abby what it means to be Abby, only the past can do
that. And so both Abbys will insist they are Abby. And both will be equally
correct.

*​>​Directly after the replication, there will be two identical twins — let
> us call them Abby-1 and Abby-2. An instant later, due to differing
> experiences, Abby-1 and Abby-2 will become different in the information
> content of their brain.*
>

Yes.

​> ​
> *So how will Abby subjectively experience this situation?*
>

We're right back to Bruno's definition problem. I can't answer your
question until you make clear what you mean by "Abby".   I can tell you
exactly precisely what I mean by "Abby", its whoever remembers being Abby
before the duplication. Yes its odd that there are 2 people that meet that
criteria, but odd is not the same thing as paradoxical. I've given you mine
so what is your precise definition of "Abby"?


> *​>​This seems like a tricky question, even in terms of our terminology of
> successor states. According to the previous section, we must conclude that
> Abby will (after the malfunction) experience a successor state.*
>

If you're interested in consciousness and subjectivity you will get nowhere
pondering on the nature of successor states, it would be like pushing on a
string. If you don't want to get tied up in logical knots and self
contradictions you've got to define personal identity based on previous
states not successor states; otherwise you wouldn't even know who you are
because you don't know what your successor state will be. But you do know
what your previous state was. We don't live in the future because we never
know what the future will be, we live in the present and the past through
memory because we know what the past was.


> *​>​But now, there are two successor states in the world: that of Abby-1
> and that of Abby-2.*
>

​That always happens when something has been duplicated. The only reason it
seems odd is that nothing as complex as a person has been duplicated
before, but this is only due to current technological limitations, it has
nothing to do with any fundamental scientific or philosophic limitation.


> ​>​
> Thus Abby will end up as Abby-1 or Abby-2, but which one of them?
>

​
One? There can't be one because Abby has been duplicated and when something
has been duplicated there is no longer just one.


> *​>​And what about the other twin?*
>

What about her?


> ​*>​*
> *Abby-1 and Abby-2 will both behave as if they were legitimate successors
> of pre-teleportation Abby.*
>

Because both will remember being Abby before the duplication.


> * ​>​In other words, Abby-1 and Abby-2 will both believe they are Abby*
>

And both will believe correctly by my definition of "Abby". But you haven't
given me your definition of "Abby".

*> However, they will both only experience themselves, and not the other
> one.*


Assuming they 

Re: Bootstrapping Reality: The inconsistency of nothing

[Bruno Marchal]

> On 16 Jul 2018, at 14:15, Bruce Kellett  wrote:
> 
> From: Bruno Marchal mailto:marc...@ulb.ac.be>>
>> 
>>> On 16 Jul 2018, at 03:57, Bruce Kellett >> > wrote:
>>> 
>>> Other directions are irrelevant to the measurement. The state is not in a 
>>> superposition of eigenvectors of every possible orientation.
>> 
>> After the measurement is done, and this makes sense only with orthogonal 
>> measurement from Alice and Bob parts, if not, as I say above, the notion of 
>> belonging to the same world makes no sense. You tall like if a measurement 
>> determine which world they are both in, which is true only for particular 
>> case, when they made the measurement of the spin or polarisation in 
>> correspond direction.
> 
> This is simply wrong. The state is a superposition of up and down for both 
> observers, regardless of whether their measurements are along the same axis 
> or not. The measurement does determine the world in which they will find 
> themselves when they meet. Just think through the significance of the facts 
> that they record their measurements in their lab books as they go along; they 
> are in the same world when they meet; and they can't jump between worlds at 
> any point. The logical conclusion of this is that the correlated Alice/Bob 
> pair are always in the same world -- they can't be in any other world because 
> world-hopping is not allowed. When you can get this point, all the mystery of 
> EPR correlations vanishes -- they are still non-local, but that is just a 
> consequence of the non-separability of the singlet state.
> 
> All your worries about FTL are irrelevant -- as I have pointed out many 
> times. It is all a lot simpler than you seem to want to make it.
> 
> 
> ..
> 
>>> And then each tracks along a particular branching tree as recorded by the 
>>> sequence of up/down results recorded in their lab books. There is 
>>> absolutely no ambiguity here because neither Alice nor Bob can switch 
>>> between branches -- they must always be in the same branch.
>> 
>> But when non orthogonal measurement are done, this makes no sense.
> 
> It is the only thing that does make any sense. If you can't track back 
> through the history of your sequences of branches -- by referring to your lab 
> book if necessary -- then Everettian branching worlds make no sense. And it 
> does not matter whether the measurements are orthogonal or not -- they always 
> end up with Alice and Bob meeting in one world with sequences of measurements 
> made in that world. Once you can grasp this, Bruno, you might gain some 
> insight into both Everett and EPR.
> 
> 
> 
> 
>> 
>> I did. I referred also to Pirce FAQ for a good approximation.
> 
> The Price account assumes non-locality -- as I have pointed out on many 
> occasions.
> 
>> You are the one invoking the FTL, so I think you are the one who should 
>> explain where that comes from, and how to test it experimentally. Aspect 
>> experience test non-locality or inseparability, not FTL.
> 
> You keep accusing me of invoking FTL. I have never done any such thing. All I 
> have talked about is the non-separability of the state and the fact that the 
> spin measurements are made non-locally. If you invoke FTL then you are 
> invoking a non-local hidden variable. I see no need to do this, and never 
> have done. Stop reading things into my arguments that are not there.
> 
> 
> 
> 
>>> There are not an infinity of worlds, there are only 2^N of them. Of course 
>>> the correlations come out right for every Alice/Bob pair when they meet. 
>>> But you have not explained this locally.
>> 
>> That is exactly what the wave explains, when you dismiss all collapse. The 
>> wave evolves purely locally in the phase space, which is the real 
>> “mutiversal” reality (up to some gauge nuances).
> 
> The wave function, as Maudlin explains, is itself non-local. So you have not 
> magically restored locality by invoking the wave function. The wave function 
> for this state is non-separable = non-local.
> 
> 
> 
> 
> 
> 
> In fact, the multi-branching tree forms a giant superposition, and we 
> have just singled out one component of this superposition. There is 
> nothing at all mysterious in this -- it is what physicists do all the 
> time when they perform calculations in momentum space -- on just one 
> component of the superposition that makes up a wave packet.
 
 That makes sense.
>>> 
>>> That is what I have been saying all along, and this is what removes your 
>>> worry about 'collapse models' -- they are just a branch from the 
>>> many-worlds superposition.
>> 
>> 
>> I don’t see how you would do that when Alice and Bob makes non orthogonal 
>> measurements. 
> 
> You don't understand the underlying quantum mechanics in that case.
> 
> 
> 
> 
>>> The "giant superposition", in so far as it exists, has been spirited away 
>>> by just looking at a single branch. There is nothing the "giant 

Re: Radioactive Decay States

[Bruno Marchal]

> On 15 Jul 2018, at 15:48, 'scerir' via Everything List 
>  wrote:
> 
> ---  SCERIR;  IN YOU OWN WORDS; WHAT DO YOU BELIEVE AND WHY? AG
> 
> Is the state ψ (i.e. a superposition state) a physically object or is it an 
> abstract entity that merely provides information about the system?
> 
> This is the question.
> 
> 


Good question. It provides relative (indexical) information. Eventually, with 
mechanism, it has to be first person plural, which means that we share *some* 
computations. It means that we are multiplied together, like in the WM 
duplication where the outsider decide to follow the candidate in the cut and 
copy boxes. QM illustrates this directly by the linearity of the tensor 
products, which has not yet be recovered in the arithmetical self-referential 
(indexical) modes of the universal machine.




> This mystery is the fact that no physical property is, in general, a 
> possessed property unless it is measured.
> 
> 

Hmm…. That is saying too much, and can lead to solipsism. To have a sharable 
(sheaf of) computation(s), we need things existing relatively to us before we 
do a measurement. If not, the dinosaurs would have survived the asteroids just 
by closing they eyes and ears. 

Bruno





> 
> 
> 
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Re: Radioactive Decay States

[Bruno Marchal]

> On 13 Jul 2018, at 01:55, agrayson2...@gmail.com wrote:
> 
> 
> 
> On Wednesday, July 11, 2018 at 2:16:24 PM UTC-6, agrays...@gmail.com wrote:
> 
> 
> On Tuesday, July 10, 2018 at 4:42:44 PM UTC-6, Brent wrote:
> 
> 
> On 7/10/2018 3:01 PM, agrays...@gmail.com <> wrote:
>> IIRC, the above quote is also in the Wiki article. It's not a coherent 
>> argument; not even an argument but an ASSERTION. Let's raise the level of 
>> discourse. It says we always get a or b, no intermediate result when the 
>> system is in a superposition of states A and B.. Nothing new here. Key 
>> question: why does this imply the system is in states A and B SIMULTANEOUSLY 
>> before the measurement? AG  
> 
> Because, in theory and in some cases in practice, there is a direct 
> measurement of the superposition state, call it C, such that you can directly 
> measure C and always get c, but when you have measured and confirmed the 
> system is in state c and then you measure A/B you get a or b at random.   The 
> easiest example is SG measurements of sliver atom spin orientation where spin 
> UP can be measured left/right and get a LEFT or a RIGHT at random, but it can 
> be measured up/down and you always get UP.  Any particular  orientation can 
> be written as a superposition of two orthogonal states.  
> 
> When you're trying to explain esoteric issues to a moron in physics, you need 
> to be more explicit. These are the issues that cause confusion and caused me 
> to fail to "get it". After some subsequent posts, you seem to be saying that 
> in an SG spin experiment where the measurement base is UP/DN, the system 
> being measured is ALSO in a superposed LEFT/RIGHT state which is also 
> measured (by an SG device designed to measure spin?), and that the LEFT/RIGHT 
> superposed state persists with some persistent eigenvalue after UP/DN is 
> measured. It's murky for us morons.  How does one get the system to be 
> measured in a superposition of RIGHT/LEFT; what is the operator for which 
> that superposition is an eigenstate, and what is the value of the persistent 
> eigenvalue?
> 
> Furthermore, you finally assert that since the RIGHT/LEFT state persists -- 
> meaning that particle is in some DEFINITE state after the spin is measured -- 
> and since (as you finally, finally assert) that that state can be written as 
> a superposition of UP/DN, all is well -- in the sense that we can now be 
> certain that the system is physically and simultaneously in the UP and DN 
> states (which I am claiming is a fallacy). 
> 
> HOWEVER, assuming that I understand your argument after filing the gaps in 
> your presentation (and pointing to some unanswered issues), I now must "rant" 
> again that the UP/DN superposed representation is NOT unique. Thus, since 
> there are finitely many or uncountable many such representations, and since 
> (as per LC) QM has no preferred basis, your argument for the physical 
> simultaneity of UP and DN states fails. I mean, I could write the superposed 
> states in the basis (UP + DN) and (UP - DN), or in many other bases. Absent 
> uniqueness of bases, one cannot assert that the system is physically and 
> simultaneously in any particular pair of basis vectors.
> 
> AG
> 
> I've been looking over your references to Peres. CMIIAW, but AFAICT he 
> doesn't deal with the issue I have been "ranting" about; namely, the 
> non-uniqueness of bases, implying IMO that the concept of simultaneous 
> physical states of the components of a superposition is an additional, 
> unsupported assumption of QM which leads to some popular misconceptions of 
> what QM is telling us.


Then you need to find a new explanation of the interference that occurs in 
basically all quantum experiments, like the two slits, the statistics of 
results with Stern-Gerlach spin measuring apparatus, etc.
The whole point of the physical wave amplitudes is that the diverse superposed 
components have a physical role, through destructive or constructive, or in 
between, interference.
Note that the discussion here supposed the quantum theory, but you are free of 
course to propose an alternative. Many have tried without success, though.

Bruno





> Incidentally, when you earlier referred to a RIGHT/LEFT superposition, did 
> you mean circular polarization, or right and left directions in a SG 
> apparatus in relation to Up/Dn measurements? TIA, AG  
> 
> This is true in general.  Any state can be written as a superposition of 
> states in some other basis.  But it is not generally true that we can prepare 
> or directly measure a system in any given state.  So those states we can't 
> directly access, we tend to think of them as existing only as superpositions 
> of states we can prepare.
> 
> Brent
> 
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Re: Bootstrapping Reality: The inconsistency of nothing

[Bruce Kellett]

From: *Bruno Marchal* mailto:marc...@ulb.ac.be>>


On 16 Jul 2018, at 03:57, Bruce Kellett > wrote:


Other directions are irrelevant to the measurement. The state is not 
in a superposition of eigenvectors of every possible orientation.


After the measurement is done, and this makes sense only with 
orthogonal measurement from Alice and Bob parts, if not, as I say 
above, the notion of belonging to the same world makes no sense. You 
tall like if a measurement determine which world they are both in, 
which is true only for particular case, when they made the measurement 
of the spin or polarisation in correspond direction.


This is simply wrong. The state is a superposition of up and down for 
both observers, regardless of whether their measurements are along the 
same axis or not. The measurement does determine the world in which they 
will find themselves when they meet. Just think through the significance 
of the facts that they record their measurements in their lab books as 
they go along; they are in the same world when they meet; and they can't 
jump between worlds at any point. The logical conclusion of this is that 
the correlated Alice/Bob pair are always in the same world -- they can't 
be in any other world because world-hopping is not allowed. When you can 
get this point, all the mystery of EPR correlations vanishes -- they are 
still non-local, but that is just a consequence of the non-separability 
of the singlet state.


All your worries about FTL are irrelevant -- as I have pointed out many 
times. It is all a lot simpler than you seem to want to make it.



..

And then each tracks along a particular branching tree as recorded by 
the sequence of up/down results recorded in their lab books. There is 
absolutely no ambiguity here because neither Alice nor Bob can switch 
between branches -- they must always be in the same branch.


But when non orthogonal measurement are done, this makes no sense.


It is the only thing that does make any sense. If you can't track back 
through the history of your sequences of branches -- by referring to 
your lab book if necessary -- then Everettian branching worlds make no 
sense. And it does not matter whether the measurements are orthogonal or 
not -- they always end up with Alice and Bob meeting in one world with 
sequences of measurements made in that world. Once you can grasp this, 
Bruno, you might gain some insight into both Everett and EPR.







I did. I referred also to Pirce FAQ for a good approximation.


The Price account assumes non-locality -- as I have pointed out on many 
occasions.


You are the one invoking the FTL, so I think you are the one who 
should explain where that comes from, and how to test it 
experimentally. Aspect experience test non-locality or inseparability, 
not FTL.


You keep accusing me of invoking FTL. I have never done any such thing. 
All I have talked about is the non-separability of the state and the 
fact that the spin measurements are made non-locally. If you invoke FTL 
then you are invoking a non-local hidden variable. I see no need to do 
this, and never have done. Stop reading things into my arguments that 
are not there.





There are not an infinity of worlds, there are only 2^N of them. Of 
course the correlations come out right for every Alice/Bob pair when 
they meet. But you have not explained this locally.


That is exactly what the wave explains, when you dismiss all collapse. 
The wave evolves purely locally in the phase space, which is the real 
“mutiversal” reality (up to some gauge nuances).


The wave function, as Maudlin explains, is itself non-local. So you have 
not magically restored locality by invoking the wave function. The wave 
function for this state is non-separable = non-local.







In fact, the multi-branching tree forms a giant superposition, and 
we have just singled out one component of this superposition. There 
is nothing at all mysterious in this -- it is what physicists do 
all the time when they perform calculations in momentum space -- on 
just one component of the superposition that makes up a wave packet.


That makes sense.


That is what I have been saying all along, and this is what removes 
your worry about 'collapse models' -- they are just a branch from the 
many-worlds superposition.



I don’t see how you would do that when Alice and Bob makes non 
orthogonal measurements.


You don't understand the underlying quantum mechanics in that case.




The "giant superposition", in so far as it exists, has been spirited 
away by just looking at a single branch. There is nothing the "giant 
superposition" can add to the conclusions obtained from just one branch.


? It changes the result of further possible measurement, notably 
involving Alice and Bob possible amnesia, in theory. Collapse has to 
be non local to make sense, as Eistein made already clear in 1927. It 
is just worst with the singlet state, but here too, 

Re: Bootstrapping Reality: The inconsistency of nothing

[Bruno Marchal]

> On 16 Jul 2018, at 03:57, Bruce Kellett  wrote:
> 
> From: Bruno Marchal mailto:marc...@ulb.ac.be>>
>>> On 12 Jul 2018, at 14:09, Bruce Kellett >> > wrote:
>>> 
>>> From: Bruno Marchal mailto:marc...@ulb.ac.be>
> On 12 Jul 2018, at 04:04, Bruce Kellett  > wrote:
> 
> There are no up' or down' branches.
 
 
 ? (That contradicts directly what you just said). A up-branch is just a 
 branch where Alice saw or would see “up”.
>>> 
>>> You were the one who introduce up-prime and down-prime branches. I maintain 
>>> that there are only two branches on each and every measurement, an 
>>> up-branch and a down-branch.
>> 
>> In which direction?
> 
> In the direction in which the measurement is made.

OK. But there are many, and if they are not orthogonal, there is no trans-world 
notion available. The first person indeterminacy selection remains local.



> One of your enduring mistakes is to confuse the rotational symmetry of the 
> singlet state with the single basis corresponding to the direction in which 
> the measurement will be made.

I don’t think so.



> Once a direction is chosen, the state can be represented as a superposition 
> of up and down eigenvectors in that direction.

No doubt on this.


> Other directions are irrelevant to the measurement. The state is not in a 
> superposition of eigenvectors of every possible orientation.

After the measurement is done, and this makes sense only with orthogonal 
measurement from Alice and Bob parts, if not, as I say above, the notion of 
belonging to the same world makes no sense. You tall like if a measurement 
determine which world they are both in, which is true only for particular case, 
when they made the measurement of the spin or polarisation in correspond 
direction.




> Quantum mechanics does not have any such superposition. The state is a 
> superposition of just two eigenvectors, although which eigenvectors depends 
> on the direction chosen.

The singlet state is not dependent of the choice of any spin direction. The 
singlet state is rotationally invariant. We could use any base.





> 
> 
>>> ..
> Each measurement splits a branch, but branches never meet or recombine.
 
 Because they both measure in the same direction (not sure how they do that 
 btw), but for Bell’s inequality, some measurement are not “orthogonal”. 
 Partial fusion is in play, which forbids ti associate each personal 
 experience with any definite Alice (Bob) in the branching.
>>> 
>>> Perhaps I was not sufficiently clear. I am considering a series of N trials 
>>> in which both Alice and Bob independently choose random magnet 
>>> orientations. So if the relative angle is theta, the probabilities for 
>>> combined results are:
>>> 
>>> Alice gets up: then Bob has  probability sin^2(theta/2) for up, and 
>>> probability cos^2(theta/2) for down.
>>> 
>>> Alice gets down: then Bob has probability cos^2(theta/2) for up, and 
>>> probability sin^2(theta/2) for down.
>>> 
>>> If theta = 0, then if Alice gets up then Bob down 100%.; Alice down then 
>>> Bob up 100%.
>>> If theta = 120 degrees, then if Alice gets up, then Bob gets up 75% 
>>> probability, and down 25% probability.
>>> And so on for other angles and combined results. It is these probabilities 
>>> that are crucial for getting the correct correlations when Alice and Bob 
>>> meet.
>>> 
>>> Now if you can get these correlations without the non-local knowledge of 
>>> this relative angle, then you have a local explanation. But you will never 
>>> be able to produce such a set of probabilities locally -- the relative 
>>> angles are set at random:  non-locally at space-like separations.
>> 
>> But the result of the measurement are determined by the singlet state. They 
>> just cannot known there local angles.
> 
> Of course they know their local angles -- they choose them! The point is that 
> Alice does not know Bob's chosen angle when she makes her measurement, and 
> neither does Bob know Alice's angle when he makes his measurement. The fact 
> that the probabilities depend on the relative angle between these random 
> non-local choices is the conundrum to be answered.
> 
> 
>> When they measure in non orthogonal “direction”, the probabilities depends, 
>> for all Alice-Bod couples, of that state, which is unknown to both of them.I 
>> am OK that it is non-local, but that does not entail that when Alice makes a 
>> measurement, she influence Bob’s outcome by a FTL influence. They just get 
>> aware locally of which sub partition they both belong.
> 
> That is just avoiding the issue. 'Sub-partition' as you use it here has no 
> meaning. Alice and Bob both know what world they are in -- the world in which 
> they got up that morning and had their breakfast. And they are in that 
> same world when they later meet after a series of trials -- they cannot 
> change worlds!

I don’t see