subject:"Re\: Born's rule from almost nothing"


> On 30 Jan 2021, at 05:06, Alan Grayson  wrote:
> 
> 
> 
> On Friday, January 29, 2021 at 8:19:47 PM UTC-7 Alan Grayson wrote:
> On Friday, January 29, 2021 at 3:00:17 PM UTC-7 Brent wrote:
> 
> 
> On 1/29/2021 5:52 AM, Bruno Marchal wrote:
>> 
>>> If you induce decoherence by measuring at the slits, then the interference 
>>> pattern disappears -- you have certainly created a separate "world" for 
>>> each path, but these can no longer interfere. That is part of the 
>>> definition of the "worlds" that are created by irreversible decoherence.
>> 
>> 
>> No problem.
>> 
>> 
>>> 
>>> So the concept of "world" is, indeed, well-defined in physics.
>> 
>> 
>> By giving a magic role to the observer, or its consciousness, or of 
>> measurement. The observer can no more be a machine in that picture.
> 
> There's no magic or observer invoked.  That's the function of decoherence, 
> which operates independent of observers or deliberate measurement.
> 
> 
>> 
>> 
>> 
>> 
>>> It might not be defined in logic or metaphysics, but this is of no concern 
>>> to the working physicist -- we know perfectly well what we mean by "a 
>>> world”.
>> 
>> FAPP. OK.
>> The goal here is to try to understand what happens.
>> 
>> 
>> 
>>> And we can readily tell when someone is talking nonsense by claiming that 
>>> "worlds interfere statistically without interacting”.
>> 
>> ? (That is rather standard, and pretty obvious, I would say).
> 
> Really?  I've never heard of it and it seems pretty obviously nonsense to me.
> 
> I made a similar comment when this word salad of nonsense was first posted by 
> Bruno. It's Trump Physics in spades, full of sound and fury but signifying 
> nothing; that is, no contact with real physics. Yet you think I go too far. 
> Baffling. AG 
> 
> Another weirdness is the MWI claim by the usual suspects that QM leaves 
> "measurement" and "observer" undefined. 

Because the collapse is itself not explain, and this introduce a dualism in the 
ontology. Bohr was aware of this.

With Everett, the observer is well defined, although Everett does not do it 
mathematically. It invokes an automata, but in fact his argument has to be 
generalised on arithmetic if that automata is Turing universal, like us.  
Everett confirms the “many-histories” inherent in the fact that all 
computations are realised in the standard model of arithmetic (which can be 
defined by the intersection of all models of arithmetic).

Bruno



> I explained this earlier, but alas, they prefer their ridiculous claims. 
> E.g., in the double slit experiment, a "measurement" occurs when a particle 
> hits the screen. The "observer" is anyone or anything that records the 
> result. Nothing particularly deep here, but the usual suspects find these 
> definitions woefully wanting. Trump Physics in play. AG






>  
> 
> Brent
> 
> 
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Re: Born's rule from almost nothing


> On 30 Jan 2021, at 00:37, Bruce Kellett  wrote:
> 
> On Sat, Jan 30, 2021 at 1:41 AM Bruno Marchal  > wrote:
> On 28 Jan 2021, at 06:58, Bruce Kellett  > wrote:
>> 
>> This is certainly a problem for Deutsch's interpretation of 'world'. Because 
>> there are an infinite number of equivalent sets of basis vectors available 
>> for every Hilbert space, it makes little sense to claim that an observer is 
>> uncertain as to which basis he is in. He could choose any basis whatsoever. 
>> But if he wants his choice to make sense in his lived life, he would be wise 
>> to choose the basis that is singled out by decoherence as stable against 
>> environmental degradation. In other words, he has to rely on decoherence to 
>> solve the basis problem. Deutsch has no way of resolving the preferred basis 
>> problem in his approach since, to him, all bases correspond to equivalent 
>> 'worlds’.
> 
> That is why it is preferable to abandon the idea of “world” (an idea which 
> BTW belongs more to metaphysics than physics) and use the “relative state”, 
> or the “history” notions instead.
> 
> Decoherence is irreversible from inside the multiverse for the same reason 
> that statistical physics is reversible, in Everett. The whole “universe” 
> remains “in principle” reversible, bit not from inside, unless amnesia and 
> ultra-sophisiticated technology (which doubtfully could ever exist).
> 
> 
> It is difficult to give any sensible meaning to a statement like this. The 
> idea behind the universality of unitary evolution  in Everettian QM is that 
> the initially pure state always remains pure.

Yes, the “universal wave function remains pure”, and describes the same 
relative internal histories independently of the choice of the base, as Everett 
show. I extend this into “independent of the ontology assumes as long as it is 
equivalent to a universal (Turing) machinery or machine.



> In an interaction with decoherence, the off-diagonal elements of the density 
> matrix remain finite, albeit arbitrarily small. This means that there always 
> remains a non-zero probability that the state will recohere.

Yes, requiring some amnesty by the observers.


> 
> But this picture is, in fact, wrong. As has been pointed out, the 
> irreversibility introduced by decoherence is actually an 'in principle' 
> irreversibility,

Only in the internal relative perspective. That’s true, but false for the 
“universal wave”, or “universal machine" in case we start from a reversible one 
(but given what we observe, that would be a sort of cheating preventing us to 
distinguish the qualia from the quanta later).



> induced by the laws of physics, such as the speed of light being an upper 
> limit on possible speeds, and the laws of thermodynamics limiting local 
> decreases in entropy. Once decoherence entangles the results of any 
> interaction with the wider thermal environment, it is not possible to avoid 
> the loss of information to outer space via the emission of IR photons. This 
> process is in principle irreversible, because these photons can never be 
> captured and returned.

Indeed.




> What is more, decoherence is general and will always result in entanglement 
> with the wider thermal environment. And this entanglement will generally 
> happen very quickly -- in fractions of a second. So the loss of thermal 
> photons is essentially instantaneous. Given this, the probability that the 
> initial state will eventually recohere is exactly zero. If the density matrix 
> is to reflect this physical reality, then the off-diagonal elements will have 
> to be set to precisely zero, the pure state has to reduce to a mixture.

Yes, but only from an observer’s viewpoint. Not from the general third person 
description made possible by the formalisme.




> This cannot happen by unitary evolution, true, so unitary evolution itself 
> cannot reflect the whole of physical reality.

Indeed, but again, the non-unitary collapse has been added to get rid of the 
alternate histories, given that we can’t access them without erasing our 
memories, which is usually not an interesting thing to do in a history.



> The limit as the off-diagonal elements of the density  matrix become small 
> via decoherence, and approach zero, is a singular limit -- the progression 
> from infinitesimal to zero is not continuous. The Schrodinger equation cannot 
> capture this singular limit so it cannot capture the whole of the physical 
> reality. The "collapse postulate" has a sound physical basis! Decoherence 
> does, indeed, lead the initially pure state to become mixed. That is 
> physically unavoidable.

>From the relative position of the observer. But the collapse, as Both 
>eventually admit, is not a physical happening. It is all in the mind of the 
>“alternate observer”, or even just the alternate computational state (in 
>arithmetic, or in the universal wave).



> 
> Claiming that the

Re: Born's rule from almost nothing


> On 29 Jan 2021, at 23:00, 'Brent Meeker' via Everything List 
>  wrote:
> 
> 
> 
> On 1/29/2021 5:52 AM, Bruno Marchal wrote:
>> 
>>> If you induce decoherence by measuring at the slits, then the interference 
>>> pattern disappears -- you have certainly created a separate "world" for 
>>> each path, but these can no longer interfere. That is part of the 
>>> definition of the "worlds" that are created by irreversible decoherence.
>> 
>> 
>> No problem.
>> 
>> 
>>> 
>>> So the concept of "world" is, indeed, well-defined in physics.
>> 
>> 
>> By giving a magic role to the observer, or its consciousness, or of 
>> measurement. The observer can no more be a machine in that picture.
> 
> There's no magic or observer invoked.  That's the function of decoherence, 
> which operates independent of observers or deliberate measurement.

In the “Many-Histories”? Then I am OK. 

It is magic if one histories is made “more real” than another one.

Bruno




> 
>> 
>> 
>> 
>> 
>>> It might not be defined in logic or metaphysics, but this is of no concern 
>>> to the working physicist -- we know perfectly well what we mean by "a 
>>> world”.
>> 
>> FAPP. OK.
>> The goal here is to try to understand what happens.
>> 
>> 
>> 
>>> And we can readily tell when someone is talking nonsense by claiming that 
>>> "worlds interfere statistically without interacting”.
>> 
>> ? (That is rather standard, and pretty obvious, I would say).
> 
> Really?  I've never heard of it and it seems pretty obviously nonsense to me.
> 
> Brent
> 
>> 
>> 
> 
> 
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Re: Born's rule from almost nothing


> On 29 Jan 2021, at 19:55, Alan Grayson  wrote:
> 
> 
> 
> On Friday, January 29, 2021 at 7:30:42 AM UTC-7 Bruno Marchal wrote:
>> On 28 Jan 2021, at 02:07, Alan Grayson > > wrote:
>> 
>> 
>> 
>> On Wednesday, January 27, 2021 at 9:20:15 AM UTC-7 Bruno Marchal wrote:
>> 
>>> On 17 Jan 2021, at 03:03, Pierz Newton-John > wrote:
>>> 
>>> 
>>> 
>> 
>>> On Sun, 17 Jan 2021 at 3:49 am, Alan Grayson > wrote:
>>> What would be the mechanism or process for other worlds to interact with 
>>> each other, that is to interfere with each other? This is the gorilla in 
>>> the room that many MWI enthusiasts ignore; awesome speculation with zero 
>>> grounding in empirical evidence. Something definitely awry with this pov. AG
>>> 
>> 
>>> I’m not an “enthusiast”. It’s a physical theory not a football team. If 
>>> anything I dislike the idea of all those alternative variants of me and my 
>>> life. If MWI is disproved I’ll be perfectly happy. It’s just that it 
>>> unfortunately makes more sense in my assessment than any other alternative, 
>>> so I entertain it as the most likely explanation for the observed data. To 
>>> say it has zero grounding in empirical data is simply false  - it’s the 
>>> theory that simply takes the empirical data to its logical conclusion 
>>> without adding a collapse postulate. The wave function is the whole thing. 
>>> Asking what the mechanism is for worlds to interfere with one another is 
>>> the same as asking what the mechanism is for the Schrödinger wave function 
>>> to interfere with itself. In the dual slit experiment it’s an observed 
>>> fact. It makes no sense for it to behave that way if we stick to the old 
>>> view of matter as little hard balls, but there you go. When we talk of 
>>> “worlds”, it just refers to a ramifying quantum state, and it is in the 
>>> nature of quantum states to interfere with themselves per the dual slit 
>>> experiment, even if they become large and complex. Interference ceases when 
>>> two branches of the universal quantum state diverge far enough that they 
>>> completely decohere. When you say “what is the mechanism?” that really 
>>> means “what is the mathematical description?” in physics. Anything else is 
>>> just imprecise circumlocution like the word “world” in this context. So the 
>>> mechanism for interference is the Schrödinger equation, which predicts such 
>>> interference. MWI adds precisely nothing to that mathematical description.
>> 
>> 
>> Yes. To avoid the MWI, the early founders of QM *added* an axiom: the wave 
>> collapse postulate. But it introduce a non intelligible dualism with an 
>> unknown theory of mind. It makes everything more complicated, for reason of 
>> philosophical taste, which is alway dubious. Occam Razor favour the theory 
>> with as much axioms as possible.
>> 
>> Especially if one believe in Mechanism. This asks us to believe that 2+2=4 & 
>> Co., which entails the existence of all computations, with a extraordinary 
>> complex redundancy of those computations, implying the existence of a 
>> (Lebgues) Measure on their first person limit (the “observer” cannot be 
>> aware of the number of steps of the universal dovetailing (which occur in 
>> all models of any  theory of arithmetic). So ...
>> 
>> Bruno
>> 
>> Are irrational numbers, other than say PI or e, and possibly a few others, 
>> computable? AG 
> 
> 
> By Cantor theorem, the set of irrational numbers is non countable. The set of 
> computable things is countable, so there are uncountably many irrational 
> number which are not computable.
> 
> Some precise irrational numbers exists, like the one build from the 
> characteristic function of non computable set, like the halting set (the set 
> of code of non halting programs) or TOT (the set of code of total computable 
> functions…).
> 
> In arithmetic most sets of numbers, including many having some use, are not 
> computable.
> 
> In computer science, most attribute of programs are not computable. For 
> example, there is no algorithm to decide if a given code compute the null 
> function, or any function, actually. 
> 
> The computable part of mathematics is a very tiny part of mathematics.
> 
> Bruno
> 
> That's what I thought. Why then is computability an important concept? AG 


One reason is based on Descartes’ idea that our bodies are machine, which 
really means that their working involved only local distinct causations, 
handling of finitely describable information, etc. This is used by Darwin, and 
made more explicit by the geneticists, from Mendel, Morgan to molecular genetic 
and the DNA relative codings.

But there ia another reason, which is that the notion of computability is the 
only notion in epistemology which has a precise purely mathematical definition, 
thanks to the Church-Turing thesis (or the Kleene-Post thesis). Like Gödel 
eventually understood (he mlssed that thesis), there is a sort of mathematical 
miracle at play, as most metamathematical notion, like truth,

Re: Born's rule from almost nothing

2021-01-31 Thread Bruce Kellett

On Mon, Feb 1, 2021 at 4:10 PM smitra  wrote:

> The core disagreement with Bruce is the following. He wrote:
>
> "However, I have not made any appeal to Copenhagen or any other
> particular interpretation. I am simply pointing to a physical result
> that must be explainable by whatever interpretation or theory you
> adopt."

> While you can do this, you then cannot draw the conclusion that the MWI
> is wrong. For that you must analyze the situation according to the MWI,
> and if there are problems see if these are due to a formalism that
> simplifies things too much that can be repaired or if the problem is
> fundamentally unrepairable. Only in the latter case can you draw the
> conclusion that the MWI must necessarily be wrong.
>

You are saying that only if MWI can be shown to be internally inconsistent
can it be claimed that it is wrong. This is not true. If one can
demonstrate that MWI does not give results that correspond to the physical
reality, then one can conclude that MWI is inadequate as a physical theory.
So I have adopted a neutral position on the truth or falsity of MWI and
shown that it does not give an adequate account of the irreversibility of
most quantum interactions. Not that any other quantum theory necessarily
does either, but it does show a weakness in the theories that can only be
remedied by the addition of a genuine stochastic element into those
theories -- something that will recognize the reality of the transition
from a pure state to an improper mixture, which is what the entanglement
interactions do. MWI insists that only the view of the whole universe makes
sense. But that does not capture the physical fact that the process is
irreversible in principle, so MWI is inadequate to the task of explaining
the physics. In fact, this necessary irreversibility of quantum
interactions is a strong reason for preferring  genuinely stochastic
theories, such as the relativistic GRW theory.

> Previously, you were also dismissive of "quantum non-equilibrium" in the
> context of Bohm theory. If Bohm theory is true, then this is a
> possibility, no matter how ridiculous it sounds. You can't dismiss it
> out of hand and then analyze a problem and then conclude that Bohm
> theory must be false, as that would be a straw man argument.
>

I do not think I ever claimed that Bohm's theory is false. Quantum
equilibrium or non-equilibrium is a concept that has relevance only to
Bohm's theory, and the reliability of that concept can be analysed
independently. If quantum non-equilibrium is found to occur, then that has
consequences for Bohm, but if the concept is found to be irrelevant to the
physics, then it has no consequences for Bohm. It is perfectly possible to
simply add the Born rule to Bohmian mechanics as an additional postulate,
as it is added in conventional Copenhagen interpretations, for instance.
If one does not insist on trying to derive the Born rule from Bohmian
mechanics, then the question of quantum equilibrium becomes otiose.

Bruce

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Re: Born's rule from almost nothing

2021-01-31 Thread smitra


The core disagreement with Bruce is the following. He wrote:

"However, I have not made any appeal to Copenhagen or any other 
particular interpretation. I am simply pointing to a physical result 
that must be explainable by whatever interpretation or theory you 
adopt."


While you can do this, you then cannot draw the conclusion that the MWI 
is wrong. For that you must analyze the situation according to the MWI, 
and if there are problems see if these are due to a formalism that 
simplifies things too much that can be repaired or if the problem is 
fundamentally unrepairable. Only in the latter case can you draw the 
conclusion that the MWI must necessarily be wrong.


Previously, you were also dismissive of "quantum non-equilibrium" in the 
context of Bohm theory. If Bohm theory is true, then this is a 
possibility, no matter how ridiculous it sounds. You can't dismiss it 
out of hand and then analyze a problem and then conclude that Bohm 
theory must be false, as that would be a straw man argument.


Saibal


This is also similar to how people dismissed


On 30-01-2021 05:14, Bruce Kellett wrote:

On Sat, Jan 30, 2021 at 2:29 PM smitra  wrote:


On 30-01-2021 01:41, Bruce Kellett wrote:

On Sat, Jan 30, 2021 at 11:20 AM smitra  wrote:


This argument is wrong for two reasons. First, your definition of
irreversibility is wrong, it has nothing to do with the practical
impossibility to reverse the evolution of the state. Time

evolution is

said to be reversible if two different initial state will evolve

to two

different final state, which is true for unitary time evolution.


You are making exactly the same mistake as was made earlier with
Deutsch's definition of 'world'. You are using a technical

definition

that does not always relate to the usual meaning of the term.
'Reversible' means that the situation can be reversed. In this
context, it means that coherence can be restored. If you want to

mean

something different, then you should use a different term, and

your

objection collapses.


The usual meaning is wrong, the technical definition is what it is
for a
good reason.


The usual meaning is what we require in these circumstances.


That no physical process exists to get the initial state
back e.g. because time reversibility is not possible due to CP
violation
can be the case, but that does not capture the aspect of
reversibility
that one needs. Also in the example you raise with photons escaping
and
whether or not you can then get interference, as that's also not a
relevant issue in the MWI when we focus on a the state of a local
observer.


The argument that I have presented does not depend on MWI. What you do
in MWI is not really relevant because MWI still does not allow for the
reversibility of processes involving the escape of IR photons to outer
space. I am considering a particular case in order to show that
universal unitary evolution does not capture an essential element of
the physics. If you start by insisting that evolution is necessarily
always unitary, then you have begged the question. For these reasons
MWI does not get you off the hook here.




The second mistake that leads to the wrong conclusion that a pure
state
evolves to a mixed state is that this requires entanglement with

an

infinite number of physical degrees of freedom when, precisely

due

to
locality (finite c), only a finite number of degrees of freedom

get

entangled at any given time.


This is technically incorrect. There is no requirement for an

infinite

number of degrees of freedom. Escape of just one IR photon to

outer

space is sufficient to destroy reversibility. Then, in order to
reflect this irreversibility, the off-diagonal elements of the

density

matrix should be exactly zero (reducing the pure state to a

mixture).

Unitary evolution cannot give this, so unitary evolution, by

itself,

is unable to capture that whole reality about the physical state.


You are then replacing the density matrix by the reduced density
matrix
and then claiming that the reduced density matrix describes a mixed
state. That's true but irrelevant if you want to capture the whole
reality of the physical state.


What on earth is "the whole reality of the physical state"? We are
looking at the physics of a particular situation in which the physical
state is such that reversibility is impossible in principle, because
reversibility would violate the known laws of physics. The point is
that unitary evolution does not capture the reality of this situation
-- the probability of reversing is known to be exactly zero, so the
off-diagonal elements of the density matrix must vanish. This is a
non-unitary requirement. Therefore, unitary evolution does not capture
the physics of this situation. MWI does not help you here.


What this shows is that the notion of a World is only

approximate, and

therefore cannot play any role in defining what observation is,

because

we obviously do observe things and that must then have a

RE: Born's rule from almost nothing

2021-01-30 Thread Philip Benjamin

[Philip Benjamin]
https://www.quantamagazine.org/the-born-rule-has-been-derived-from-simple-physical-principles-20190213/
Schrödinger equation (1925) is a formal description of the French physicist 
Louis de Broglie’s (1924) wave-like—NOT WAVY--  behavior of quantum particles 
(electrons). It ascribes to a particle a wave function (ψ) from which the 
particle’s future behavior can be predicted. The wave function is a purely 
mathematical expression, not directly related to anything observed. Born’s bold 
pure  intuition has no specific justification.
 Born unnecessarily conceived of a “wavy nature” of quantum particles into 
real “waves of probability”. That is unwarranted, because probabilities are not 
possibilities. The Schrödinger-de Broglie “Wave-Likeness” is just adequate. 
Born indeed considered it as basically a mathematical tool for calculating the 
probabilities—not realities--  of observing a particular outcome in an 
experiment.  All the subsequent “imaginations” of a quantum world as “the 
reality” and sometimes as “ultimate reality” are pure fantasies and adult fairy 
tales—myths, mists, mindsets and mentalities. Absurdities are inherently 
associated with conceiving WAVE-LIKENESS into WAVINESS. Particles remain 
particles all the time. Even photons are corpuscles, most probably with mass at 
an indeterminate decimal place!
Philip Benjamin

<https://www.quantamagazine.org/the-born-rule-has-been-derived-from-simple-physical-principles-20190213/>
From: everything-list@googlegroups.com  On 
Behalf Of Bruce Kellett
Sent: Friday, January 29, 2021 5:11 PM
To: Everything List 
Subject: Re: Born's rule from almost nothing

On Sat, Jan 30, 2021 at 9:00 AM 'Brent Meeker' via Everything List 
mailto:everything-list@googlegroups.com>> 
wrote:
On 1/29/2021 5:52 AM, Bruno Marchal wrote:
If you induce decoherence by measuring at the slits, then the interference 
pattern disappears -- you have certainly created a separate "world" for each 
path, but these can no longer interfere. That is part of the definition of the 
"worlds" that are created by irreversible decoherence.

No problem.

So the concept of "world" is, indeed, well-defined in physics.

By giving a magic role to the observer, or its consciousness, or of 
measurement. The observer can no more be a machine in that picture.

There's no magic or observer invoked.  That's the function of decoherence, 
which operates independent of observers or deliberate measurement.

Exactly.
It might not be defined in logic or metaphysics, but this is of no concern to 
the working physicist -- we know perfectly well what we mean by "a world”.
FAPP. OK.
The goal here is to try to understand what happens.
And we can readily tell when someone is talking nonsense by claiming that 
"worlds interfere statistically without interacting”.

? (That is rather standard, and pretty obvious, I would say).

Really?  I've never heard of it and it seems pretty obviously nonsense to me.


Yes. Bruno has a fine line in nonsensical sayings that he trots out on random 
occasions when he does not have a real argument.
.

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Re: Born's rule from almost nothing

On Sat, Jan 30, 2021 at 2:29 PM smitra  wrote:

> On 30-01-2021 01:41, Bruce Kellett wrote:
> > On Sat, Jan 30, 2021 at 11:20 AM smitra  wrote:
> >>
> >> This argument is wrong for two reasons. First, your definition of
> >> irreversibility is wrong, it has nothing to do with the practical
> >> impossibility to reverse the evolution of the state. Time evolution is
> >> said to be reversible if two different initial state will evolve to two
> >> different final state, which is true for unitary time evolution.
> >
> > You are making exactly the same mistake as was made earlier with
> > Deutsch's definition of 'world'. You are using a technical definition
> > that does not always relate to the usual meaning of the term.
> > 'Reversible' means that the situation can be reversed. In this
> > context, it means that coherence can be restored. If you want to mean
> > something different, then you should use a different term, and your
> > objection collapses.
>
> The usual meaning is wrong, the technical definition is what it is for a
> good reason.

The usual meaning is what we require in these circumstances.

That no physical process exists to get the initial state
> back e.g. because time reversibility is not possible due to CP violation
> can be the case, but that does not capture the aspect of reversibility
> that one needs. Also in the example you raise with photons escaping and
> whether or not you can then get interference, as that's also not a
> relevant issue in the MWI when we focus on a the state of a local
> observer.
>

The argument that I have presented does not depend on MWI. What you do in
MWI is not really relevant because MWI still does not allow for the
reversibility of processes involving the escape of IR photons to outer
space. I am considering a particular case in order to show that universal
unitary evolution does not capture an essential element of the physics. If
you start by insisting that evolution is necessarily always unitary, then
you have begged the question. For these reasons MWI does not get you off
the hook here.

>
> >> The second mistake that leads to the wrong conclusion that a pure
> >> state
> >> evolves to a mixed state is that this requires entanglement with an
> >> infinite number of physical degrees of freedom when, precisely due
> >> to
> >> locality (finite c), only a finite number of degrees of freedom get
> >> entangled at any given time.
> >
> > This is technically incorrect. There is no requirement for an infinite
> > number of degrees of freedom. Escape of just one IR photon to outer
> > space is sufficient to destroy reversibility. Then, in order to
> > reflect this irreversibility, the off-diagonal elements of the density
> > matrix should be exactly zero (reducing the pure state to a mixture).
> > Unitary evolution cannot give this, so unitary evolution, by itself,
> > is unable to capture that whole reality about the physical state.
>
> You are then replacing the density matrix by the reduced density matrix
> and then claiming that the reduced density matrix describes a mixed
> state. That's true but irrelevant if you want to capture the whole
> reality of the physical state.
>

What on earth is "the whole reality of the physical state"? We are looking
at the physics of a particular situation in which the physical state is
such that reversibility is impossible in principle, because reversibility
would violate the known laws of physics. The point is that unitary
evolution does not capture the reality of this situation -- the probability
of reversing is known to be exactly zero, so the off-diagonal elements of
the density matrix must vanish. This is a non-unitary requirement.
Therefore, unitary evolution does not capture the physics of this
situation. MWI does not help you here.

>> What this shows is that the notion of a World is only approximate, and
> >> therefore cannot play any role in defining what observation is, because
> >> we obviously do observe things and that must then have a mathematically
> >> exact formulation, not an approximate one, no matter how accurate
> >> that approximation is.
> >
> > The definition of 'world' in the context of QM is made exact precisely
> > because of this irreversibility. Worlds are well-defined and distinct
> > precisely because they can no longer interact or recohere. The laws of
> > physics ensure this.
> >
>
> Your argument is based on replacing the exact physical state by the
> reduced density matrix, so you are smuggling in the Copenhagen
> interpetation in by hand, you are not really considering the MWI.
>

No. I agree that this is inconsistent with MWI, since MWI insists on
universal unitary evolution. If such unitary evolution cannot capture
essential elements of the physical situation, then it must be wrong. You
simply beg the question if you insist that MWI must be correct. It is under
test, so you cannot logically assume it is true from the start. However, I
have not made any appeal to Copenhagen or

Re: Born's rule from almost nothing

2021-01-29 Thread Alan Grayson



On Friday, January 29, 2021 at 8:19:47 PM UTC-7 Alan Grayson wrote:

> On Friday, January 29, 2021 at 3:00:17 PM UTC-7 Brent wrote:
>
>>
>>
>> On 1/29/2021 5:52 AM, Bruno Marchal wrote:
>>
>>
>> If you induce decoherence by measuring at the slits, then the 
>> interference pattern disappears -- you have certainly created a separate 
>> "world" for each path, but these can no longer interfere. That is part of 
>> the definition of the "worlds" that are created by irreversible decoherence.
>>
>>
>>
>> No problem.
>>
>>
>>
>> So the concept of "world" is, indeed, well-defined in physics.
>>
>>
>>
>> By giving a magic role to the observer, or its consciousness, or of 
>> measurement. The observer can no more be a machine in that picture.
>>
>>
>> There's no magic or observer invoked.  That's the function of 
>> decoherence, which operates independent of observers or deliberate 
>> measurement.
>>
>>
>>
>>
>>
>>
>> It might not be defined in logic or metaphysics, but this is of no 
>> concern to the working physicist -- we know perfectly well what we mean by 
>> "a world”. 
>>
>>
>> FAPP. OK.
>> The goal here is to try to understand what happens.
>>
>>
>>
>> And we can readily tell when someone is talking nonsense by claiming that 
>> "worlds interfere statistically without interacting”. 
>>
>>
>> ? (That is rather standard, and pretty obvious, I would say).
>>
>>
>> Really?  I've never heard of it and it seems pretty obviously nonsense to 
>> me.
>>
>
> *I made a similar comment when this word salad of nonsense was first 
> posted by Bruno. It's Trump Physics in spades, full of sound and fury but 
> signifying nothing; that is, no contact with real physics. Yet you think I 
> go too far. Baffling. AG *
>


*Another weirdness is the MWI claim by the usual suspects that QM leaves 
"measurement" and "observer" undefined. I explained this earlier, but alas, 
they prefer their ridiculous claims. E.g., in the double slit experiment, a 
"measurement" occurs when a particle hits the screen. The "observer" is 
anyone or anything that records the result. Nothing particularly deep here, 
but the usual suspects find these definitions woefully wanting. Trump 
Physics in play. AG* 

>
>> Brent
>>
>>

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Re: Born's rule from almost nothing

2021-01-29 Thread smitra


On 30-01-2021 01:41, Bruce Kellett wrote:

On Sat, Jan 30, 2021 at 11:20 AM smitra  wrote:


On 30-01-2021 00:37, Bruce Kellett wrote:


It is difficult to give any sensible meaning to a statement like

this.

The idea behind the universality of unitary evolution  in

Everettian

QM is that the initially pure state always remains pure. In an
interaction with decoherence, the off-diagonal elements of the

density

matrix remain finite, albeit arbitrarily small. This means that

there

always remains a non-zero probability that the state will

recohere.


But this picture is, in fact, wrong. As has been pointed out, the
irreversibility introduced by decoherence is actually an 'in
principle' irreversibility, induced by the laws of physics, such

as

the speed of light being an upper limit on possible speeds, and

the

laws of thermodynamics limiting local decreases in entropy. Once
decoherence entangles the results of any interaction with the

wider

thermal environment, it is not possible to avoid the loss of
information to outer space via the emission of IR photons. This
process is in principle irreversible, because these photons can

never

be captured and returned. What is more, decoherence is general and
will always result in entanglement with the wider thermal

environment.

And this entanglement will generally happen very quickly -- in
fractions of a second. So the loss of thermal photons is

essentially

instantaneous. Given this, the probability that the initial state

will

eventually recohere is exactly zero. If the density matrix is to
reflect this physical reality, then the off-diagonal elements will
have to be set to precisely zero, the pure state has to reduce to

a

mixture. This cannot happen by unitary evolution, true, so unitary
evolution itself cannot reflect the whole of physical reality. The
limit as the off-diagonal elements of the density  matrix become

small

via decoherence, and approach zero, is a singular limit -- the
progression from infinitesimal to zero is not continuous. The
Schrodinger equation cannot capture this singular limit so it

cannot

capture the whole of the physical reality. The "collapse

postulate"

has a sound physical basis! Decoherence does, indeed, lead the
initially pure state to become mixed. That is physically

unavoidable.


Claiming that the coherence is not lost to the "whole universe" is
just an empty rhetorical flourish, with no operational content.

Bruce



This argument is wrong for two reasons. First, your definition of
irreversibility is wrong, it has nothing to do with the practical
impossibility to reverse the evolution of the state. Time evolution
is
said to be reversible if two different initial state will evolve to
two
different final state, which is true for unitary time evolution.


You are making exactly the same mistake as was made earlier with
Deutsch's definition of 'world'. You are using a technical definition
that does not always relate to the usual meaning of the term.
'Reversible' means that the situation can be reversed. In this
context, it means that coherence can be restored. If you want to mean
something different, then you should use a different term, and your
objection collapses.


The usual meaning is wrong, the technical definition is what it is for a 
good reason. That no physical process exists to get the initial state 
back e.g. because time reversibility is not possible due to CP violation 
can be the case, but that does not capture the aspect of reversibility 
that one needs. Also in the example you raise with photons escaping and 
whether or not you can then get interference, as that's also not a 
relevant issue in the MWI when we focus on a the state of a local 
observer.



The second mistake that leads to the wrong conclusion that a pure
state
evolves to a mixed state is that this requires entanglement with an
infinite number of physical degrees of freedom when, precisely due
to
locality (finite c), only a finite number of degrees of freedom get
entangled at any given time.


This is technically incorrect. There is no requirement for an infinite
number of degrees of freedom. Escape of just one IR photon to outer
space is sufficient to destroy reversibility. Then, in order to
reflect this irreversibility, the off-diagonal elements of the density
matrix should be exactly zero (reducing the pure state to a mixture).
Unitary evolution cannot give this, so unitary evolution, by itself,
is unable to capture that whole reality about the physical state.


You are then replacing the density matrix by the reduced density matrix 
and then claiming that the reduced density matrix describes a mixed 
state. That's true but irrelevant if you want to capture the whole 
reality of the physical state.





What this shows is that the notion of a World is only approximate,
and
therefore cannot play any role in defining what observation is,
because
we obviously do observe things and that must then have a
mathematically
exact

Re: Born's rule from almost nothing

2021-01-29 Thread Alan Grayson



On Friday, January 29, 2021 at 3:00:17 PM UTC-7 Brent wrote:

>
>
> On 1/29/2021 5:52 AM, Bruno Marchal wrote:
>
>
> If you induce decoherence by measuring at the slits, then the interference 
> pattern disappears -- you have certainly created a separate "world" for 
> each path, but these can no longer interfere. That is part of the 
> definition of the "worlds" that are created by irreversible decoherence.
>
>
>
> No problem.
>
>
>
> So the concept of "world" is, indeed, well-defined in physics.
>
>
>
> By giving a magic role to the observer, or its consciousness, or of 
> measurement. The observer can no more be a machine in that picture.
>
>
> There's no magic or observer invoked.  That's the function of decoherence, 
> which operates independent of observers or deliberate measurement.
>
>
>
>
>
>
> It might not be defined in logic or metaphysics, but this is of no concern 
> to the working physicist -- we know perfectly well what we mean by "a 
> world”. 
>
>
> FAPP. OK.
> The goal here is to try to understand what happens.
>
>
>
> And we can readily tell when someone is talking nonsense by claiming that 
> "worlds interfere statistically without interacting”. 
>
>
> ? (That is rather standard, and pretty obvious, I would say).
>
>
> Really?  I've never heard of it and it seems pretty obviously nonsense to 
> me.
>

*I made a similar comment when this word salad of nonsense was first posted 
by Bruno. It's Trump Physics in spades, full of sound and fury but 
signifying nothing; that is, no contact with real physics. Yet you think I 
go too far. Baffling. AG *

>
> Brent
>
>
>
>
>

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Re: Born's rule from almost nothing

On Sat, Jan 30, 2021 at 11:20 AM smitra  wrote:

> On 30-01-2021 00:37, Bruce Kellett wrote:
> >
> > It is difficult to give any sensible meaning to a statement like this.
> > The idea behind the universality of unitary evolution  in Everettian
> > QM is that the initially pure state always remains pure. In an
> > interaction with decoherence, the off-diagonal elements of the density
> > matrix remain finite, albeit arbitrarily small. This means that there
> > always remains a non-zero probability that the state will recohere.
> >
> > But this picture is, in fact, wrong. As has been pointed out, the
> > irreversibility introduced by decoherence is actually an 'in
> > principle' irreversibility, induced by the laws of physics, such as
> > the speed of light being an upper limit on possible speeds, and the
> > laws of thermodynamics limiting local decreases in entropy. Once
> > decoherence entangles the results of any interaction with the wider
> > thermal environment, it is not possible to avoid the loss of
> > information to outer space via the emission of IR photons. This
> > process is in principle irreversible, because these photons can never
> > be captured and returned. What is more, decoherence is general and
> > will always result in entanglement with the wider thermal environment.
> > And this entanglement will generally happen very quickly -- in
> > fractions of a second. So the loss of thermal photons is essentially
> > instantaneous. Given this, the probability that the initial state will
> > eventually recohere is exactly zero. If the density matrix is to
> > reflect this physical reality, then the off-diagonal elements will
> > have to be set to precisely zero, the pure state has to reduce to a
> > mixture. This cannot happen by unitary evolution, true, so unitary
> > evolution itself cannot reflect the whole of physical reality. The
> > limit as the off-diagonal elements of the density  matrix become small
> > via decoherence, and approach zero, is a singular limit -- the
> > progression from infinitesimal to zero is not continuous. The
> > Schrodinger equation cannot capture this singular limit so it cannot
> > capture the whole of the physical reality. The "collapse postulate"
> > has a sound physical basis! Decoherence does, indeed, lead the
> > initially pure state to become mixed. That is physically unavoidable.
> >
> > Claiming that the coherence is not lost to the "whole universe" is
> > just an empty rhetorical flourish, with no operational content.
> >
> > Bruce
> >
>
> This argument is wrong for two reasons. First, your definition of
> irreversibility is wrong, it has nothing to do with the practical
> impossibility to reverse the evolution of the state. Time evolution is
> said to be reversible if two different initial state will evolve to two
> different final state, which is true for unitary time evolution.
>


You are making exactly the same mistake as was made earlier with Deutsch's
definition of 'world'. You are using a technical definition that does not
always relate to the usual meaning of the term. 'Reversible' means that the
situation can be reversed. In this context, it means that coherence can be
restored. If you want to mean something different, then you should use a
different term, and your objection collapses.


The second mistake that leads to the wrong conclusion that a pure state
> evolves to a mixed state is that this requires entanglement with an
> infinite number of physical degrees of freedom when, precisely due to
> locality (finite c), only a finite number of degrees of freedom get
> entangled at any given time.
>


This is technically incorrect. There is no requirement for an infinite
number of degrees of freedom. Escape of just one IR photon to outer space
is sufficient to destroy reversibility. Then, in order to reflect this
irreversibility, the off-diagonal elements of the density matrix should be
exactly zero (reducing the pure state to a mixture). Unitary evolution
cannot give this, so unitary evolution, by itself, is unable to capture
that whole reality about the physical state.


What this shows is that the notion of a World is only approximate, and
> therefore cannot play any role in defining what observation is, because
> we obviously do observe things and that must then have a mathematically
> exact formulation, not an approximate one, no matter how accurate that
> approximation is.
>


The definition of 'world' in the context of QM is made exact precisely
because of this irreversibility. Worlds are well-defined and distinct
precisely because they can no longer interact or recohere. The laws of
physics ensure this.


A definition of observation should involve defining the algorithm that
> defines the observer and the content of the observation in terms of the
> relevant local physical degrees of freedom.



Bullshit.

You make arbitrary appeals to algorithms that do not exist. Besides,
nothing that I have said is unique to the process of conscious

Re: Born's rule from almost nothing

2021-01-29 Thread smitra


On 30-01-2021 00:37, Bruce Kellett wrote:

On Sat, Jan 30, 2021 at 1:41 AM Bruno Marchal 
wrote:


On 28 Jan 2021, at 06:58, Bruce Kellett 
wrote:


This is certainly a problem for Deutsch's interpretation of
'world'. Because there are an infinite number of equivalent sets
of basis vectors available for every Hilbert space, it makes
little sense to claim that an observer is uncertain as to which
basis he is in. He could choose any basis whatsoever. But if he
wants his choice to make sense in his lived life, he would be wise
to choose the basis that is singled out by decoherence as stable
against environmental degradation. In other words, he has to rely
on decoherence to solve the basis problem. Deutsch has no way of
resolving the preferred basis problem in his approach since, to
him, all bases correspond to equivalent 'worlds’.


That is why it is preferable to abandon the idea of “world” (an
idea which BTW belongs more to metaphysics than physics) and use the
“relative state”, or the “history” notions instead.

Decoherence is irreversible from inside the multiverse for the same
reason that statistical physics is reversible, in Everett. The whole
“universe” remains “in principle” reversible, bit not from
inside, unless amnesia and ultra-sophisiticated technology (which
doubtfully could ever exist).


It is difficult to give any sensible meaning to a statement like this.
The idea behind the universality of unitary evolution  in Everettian
QM is that the initially pure state always remains pure. In an
interaction with decoherence, the off-diagonal elements of the density
matrix remain finite, albeit arbitrarily small. This means that there
always remains a non-zero probability that the state will recohere.

But this picture is, in fact, wrong. As has been pointed out, the
irreversibility introduced by decoherence is actually an 'in
principle' irreversibility, induced by the laws of physics, such as
the speed of light being an upper limit on possible speeds, and the
laws of thermodynamics limiting local decreases in entropy. Once
decoherence entangles the results of any interaction with the wider
thermal environment, it is not possible to avoid the loss of
information to outer space via the emission of IR photons. This
process is in principle irreversible, because these photons can never
be captured and returned. What is more, decoherence is general and
will always result in entanglement with the wider thermal environment.
And this entanglement will generally happen very quickly -- in
fractions of a second. So the loss of thermal photons is essentially
instantaneous. Given this, the probability that the initial state will
eventually recohere is exactly zero. If the density matrix is to
reflect this physical reality, then the off-diagonal elements will
have to be set to precisely zero, the pure state has to reduce to a
mixture. This cannot happen by unitary evolution, true, so unitary
evolution itself cannot reflect the whole of physical reality. The
limit as the off-diagonal elements of the density  matrix become small
via decoherence, and approach zero, is a singular limit -- the
progression from infinitesimal to zero is not continuous. The
Schrodinger equation cannot capture this singular limit so it cannot
capture the whole of the physical reality. The "collapse postulate"
has a sound physical basis! Decoherence does, indeed, lead the
initially pure state to become mixed. That is physically unavoidable.

Claiming that the coherence is not lost to the "whole universe" is
just an empty rhetorical flourish, with no operational content.

Bruce



This argument is wrong for two reasons. First, your definition of 
irreversibility is wrong, it has nothing to do with the practical 
impossibility to reverse the evolution of the state. Time evolution is 
said to be reversible if two different initial state will evolve to two 
different final state, which is true for unitary time evolution.



The second mistake that leads to the wrong conclusion that a pure state 
evolves to a mixed state is that this requires entanglement with an 
infinite number of physical degrees of freedom when, precisely due to 
locality (finite c), only a finite number of degrees of freedom get 
entangled at any given time.


What this shows is that the notion of a World is only approximate, and 
therefore cannot play any role in defining what observation is, because 
we obviously do observe things and that must then have a mathematically 
exact formulation, not an approximate one, no matter how accurate that 
approximation is.


A definition of observation should involve defining the algorithm that 
defines the observer and the content of the observation in terms of the 
relevant local physical degrees of freedom. There is no need to define a 
"World" which is a meaningless concept, observer's are in principle only 
aware of their own physical state. That state can contain information 
about the environment, but what matters is not the

Re: Born's rule from almost nothing

On Sat, Jan 30, 2021 at 1:41 AM Bruno Marchal  wrote:

> On 28 Jan 2021, at 06:58, Bruce Kellett  wrote:
>
>
> This is certainly a problem for Deutsch's interpretation of 'world'.
> Because there are an infinite number of equivalent sets of basis vectors
> available for every Hilbert space, it makes little sense to claim that an
> observer is uncertain as to which basis he is in. He could choose any basis
> whatsoever. But if he wants his choice to make sense in his lived life, he
> would be wise to choose the basis that is singled out by decoherence as
> stable against environmental degradation. In other words, he has to rely on
> decoherence to solve the basis problem. Deutsch has no way of resolving the
> preferred basis problem in his approach since, to him, all bases correspond
> to equivalent 'worlds’.
>
>
> That is why it is preferable to abandon the idea of “world” (an idea which
> BTW belongs more to metaphysics than physics) and use the “relative state”,
> or the “history” notions instead.
>
> Decoherence is irreversible from inside the multiverse for the same reason
> that statistical physics is reversible, in Everett. The whole “universe”
> remains “in principle” reversible, bit not from inside, unless amnesia and
> ultra-sophisiticated technology (which doubtfully could ever exist).
>

It is difficult to give any sensible meaning to a statement like this. The
idea behind the universality of unitary evolution  in Everettian QM is that
the initially pure state always remains pure. In an interaction with
decoherence, the off-diagonal elements of the density matrix remain finite,
albeit arbitrarily small. This means that there always remains a non-zero
probability that the state will recohere.

But this picture is, in fact, wrong. As has been pointed out, the
irreversibility introduced by decoherence is actually an 'in principle'
irreversibility, induced by the laws of physics, such as the speed of light
being an upper limit on possible speeds, and the laws of thermodynamics
limiting local decreases in entropy. Once decoherence entangles the results
of any interaction with the wider thermal environment, it is not possible
to avoid the loss of information to outer space via the emission of IR
photons. This process is in principle irreversible, because these photons
can never be captured and returned. What is more, decoherence is general
and will always result in entanglement with the wider thermal environment.
And this entanglement will generally happen very quickly -- in fractions of
a second. So the loss of thermal photons is essentially instantaneous.
Given this, the probability that the initial state will eventually recohere
is exactly zero. If the density matrix is to reflect this physical reality,
then the off-diagonal elements will have to be set to precisely zero, the
pure state has to reduce to a mixture. This cannot happen by
unitary evolution, true, so unitary evolution itself cannot reflect the
whole of physical reality. The limit as the off-diagonal elements of the
density  matrix become small via decoherence, and approach zero, is a
singular limit -- the progression from infinitesimal to zero is not
continuous. The Schrodinger equation cannot capture this singular limit so
it cannot capture the whole of the physical reality. The "collapse
postulate" has a sound physical basis! Decoherence does, indeed, lead the
initially pure state to become mixed. That is physically unavoidable.

Claiming that the coherence is not lost to the "whole universe" is just an
empty rhetorical flourish, with no operational content.

Bruce

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Re: Born's rule from almost nothing

On Sat, Jan 30, 2021 at 9:00 AM 'Brent Meeker' via Everything List <
everything-list@googlegroups.com> wrote:

> On 1/29/2021 5:52 AM, Bruno Marchal wrote:
>
> If you induce decoherence by measuring at the slits, then the interference
> pattern disappears -- you have certainly created a separate "world" for
> each path, but these can no longer interfere. That is part of the
> definition of the "worlds" that are created by irreversible decoherence.
>
>
> No problem.
>
>
> So the concept of "world" is, indeed, well-defined in physics.
>
>
> By giving a magic role to the observer, or its consciousness, or of
> measurement. The observer can no more be a machine in that picture.
>
>
> There's no magic or observer invoked.  That's the function of decoherence,
> which operates independent of observers or deliberate measurement.
>

Exactly.

> It might not be defined in logic or metaphysics, but this is of no concern
> to the working physicist -- we know perfectly well what we mean by "a
> world”.
>
> FAPP. OK.
> The goal here is to try to understand what happens.
>
> And we can readily tell when someone is talking nonsense by claiming that
> "worlds interfere statistically without interacting”.
>
>
> ? (That is rather standard, and pretty obvious, I would say).
>
>
> Really?  I've never heard of it and it seems pretty obviously nonsense to
> me.
>


Yes. Bruno has a fine line in nonsensical sayings that he trots out on
random occasions when he does not have a real argument.

Bruce

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Re: Born's rule from almost nothing

2021-01-29 Thread 'Brent Meeker' via Everything List

On 1/29/2021 5:52 AM, Bruno Marchal wrote:

If you induce decoherence by measuring at the slits, then the
interference pattern disappears -- you have certainly created a
separate "world" for each path, but these can no longer interfere.
That is part of the definition of the "worlds" that are created by
irreversible decoherence.

No problem.

So the concept of "world" is, indeed, well-defined in physics.

By giving a magic role to the observer, or its consciousness, or of
measurement. The observer can no more be a machine in that picture.

There's no magic or observer invoked. That's the function of
decoherence, which operates independent of observers or deliberate
measurement.

It might not be defined in logic or metaphysics, but this is of no
concern to the working physicist -- we know perfectly well what we
mean by "a world”.

FAPP. OK.
The goal here is to try to understand what happens.

And we can readily tell when someone is talking nonsense by claiming
that "worlds interfere statistically without interacting”.

? (That is rather standard, and pretty obvious, I would say).

Really? I've never heard of it and it seems pretty obviously nonsense
to me.

Brent

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Re: Born's rule from almost nothing

2021-01-29 Thread Alan Grayson



On Friday, January 29, 2021 at 7:30:42 AM UTC-7 Bruno Marchal wrote:

> On 28 Jan 2021, at 02:07, Alan Grayson  wrote:
>
>
>
> On Wednesday, January 27, 2021 at 9:20:15 AM UTC-7 Bruno Marchal wrote:
>
>>
>> On 17 Jan 2021, at 03:03, Pierz Newton-John  wrote:
>>
>>
>>
>> On Sun, 17 Jan 2021 at 3:49 am, Alan Grayson  wrote:
>>
>>> *What would be the mechanism or process for other worlds to interact 
>>> with each other, that is to interfere with each other? This is the gorilla 
>>> in the room that many MWI enthusiasts ignore; awesome speculation with zero 
>>> grounding in empirical evidence. Something definitely awry with this pov. 
>>> AG*
>>
>>
>> I’m not an “enthusiast”. It’s a physical theory not a football team. If 
>> anything I dislike the idea of all those alternative variants of me and my 
>> life. If MWI is disproved I’ll be perfectly happy. It’s just that it 
>> unfortunately makes more sense in my assessment than any other alternative, 
>> so I entertain it as the most likely explanation for the observed data. To 
>> say it has zero grounding in empirical data is simply false  - it’s the 
>> theory that simply takes the empirical data to its logical conclusion 
>> without adding a collapse postulate. The wave function is the whole thing. 
>> Asking what the mechanism is for worlds to interfere with one another is 
>> the same as asking what the mechanism is for the Schrödinger wave function 
>> to interfere with itself. In the dual slit experiment it’s an observed 
>> fact. It makes no sense for it to behave that way if we stick to the old 
>> view of matter as little hard balls, but there you go. When we talk of 
>> “worlds”, it just refers to a ramifying quantum state, and it is in the 
>> nature of quantum states to interfere with themselves per the dual slit 
>> experiment, even if they become large and complex. Interference ceases when 
>> two branches of the universal quantum state diverge far enough that they 
>> completely decohere. When you say “what is the mechanism?” that really 
>> means “what is the mathematical description?” in physics. Anything else is 
>> just imprecise circumlocution like the word “world” in this context. So the 
>> mechanism for interference is the Schrödinger equation, which predicts such 
>> interference. MWI adds precisely nothing to that mathematical description.
>>
>>
>>
>> Yes. To avoid the MWI, the early founders of QM *added* an axiom: the 
>> wave collapse postulate. But it introduce a non intelligible dualism with 
>> an unknown theory of mind. It makes everything more complicated, for reason 
>> of philosophical taste, which is alway dubious. Occam Razor favour the 
>> theory with as much axioms as possible.
>>
>> Especially if one believe in Mechanism. This asks us to believe that 
>> 2+2=4 & Co., which entails the existence of all computations, with a 
>> extraordinary complex redundancy of those computations, implying the 
>> existence of a (Lebgues) Measure on their first person limit (the 
>> “observer” cannot be aware of the number of steps of the universal 
>> dovetailing (which occur in all models of any  theory of arithmetic). So ...
>>
>> Bruno
>>
>
> *Are irrational numbers, other than say PI or e, and possibly a few 
> others, computable? AG *
>
>
>
> By Cantor theorem, the set of irrational numbers is non countable. The set 
> of computable things is countable, so there are uncountably many irrational 
> number which are not computable.
>
> Some precise irrational numbers exists, like the one build from the 
> characteristic function of non computable set, like the halting set (the 
> set of code of non halting programs) or TOT (the set of code of total 
> computable functions…).
>
> In arithmetic most sets of numbers, including many having some use, are 
> not computable.
>
> In computer science, most attribute of programs are not computable. For 
> example, there is no algorithm to decide if a given code compute the null 
> function, or any function, actually. 
>
> The computable part of mathematics is a very tiny part of mathematics.
>
> Bruno
>

*That's what I thought. Why then is computability an important concept? AG *

 

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Re: Born's rule from almost nothing


> On 28 Jan 2021, at 06:58, Bruce Kellett  wrote:
> 
> On Thu, Jan 28, 2021 at 3:42 PM Pierz Newton-John  > wrote:
> > On 28 Jan 2021, at 2:49 pm, 'Brent Meeker' via Everything List 
> >  > > wrote:
> > On 1/27/2021 5:11 PM, Pierz Newton-John wrote:
> >> I’m not saying decoherence is reversible. I’ve corrected myself (or 
> >> accepted your correction) on that point. But my understanding of proposals 
> >> for disconfirming MWI involve extending quantum coherence to larger and 
> >> larger scales. Deutsch has argued that if we can get enough qubits into a 
> >> quantum computation, we’ve effectively “proved” MWI since “where did all 
> >> that information come from?".
> > 
> > And Scott Aaronson has pointed out it all had to be in this world in order 
> > for interference to produce an answer.
> > 
> That argument rests on the definition of world as a decohered branch, and 
> Deutsch would not accept that definition.
> 
> 
> I agree. Deutsch has his own idiosyncratic definition that does not accord 
> with common usage. The trouble is that the word 'world' has an ordinary, 
> everyday use, and if you make a technical definition of something that is 
> quite different from the everyday meaning, but use the same word, you open 
> yourself to equivocation and invalid arguments.
> 
> Deutsch is using a technical definition of 'world' which corresponds to the 
> notion of a distinct basis for a particular Hilbert space. So, in his terms, 
> there are separate 'worlds' for every possible basis. In common usage, the 
> word 'world' is reserved for bases that are singled out by decoherence as the 
> preferred, stable bases. If you use the word 'world' for any and  every one 
> of the infinite number of possible bases for any given Hilbert space, then 
> you have deprived the word of any sensible referent or meaning. The word 
> 'branch' is likewise unavailable to Deutsch, because it has a similar 
> everyday meaning to 'world ' in this context. He could use the term 'Hilbert 
> space basis', but that robs his catch phrase of its impact : "Quantum 
> computers work because every possible calculation is performed in some basis 
> of the Hilbert space." Bases in Hilbert space do not evidently have the same 
> computational resources as other worlds. So Deutsch's argument rests on an 
> equivocation between the meanings of 'world'. His argument is patently 
> invalid.
> 
> 
> I’m not sure if I agree with his argument, but I’m also not necessarily 
> convinced by that definition of “world”. I mean, it’s perfectly good as far 
> as it goes, but I’m not sure I’m happy with it being marshalled as an 
> argument in this way. If there is a world W which contains an electron in an 
> up/down superposition, then in the Deutsch picture, and I would say the 
> Everett picture in general, that means some observer in W is unaware of which 
> world he/she is in: the one where the electron is up or the one where it is 
> down. Or rather (and this is Deutsch not Everett), the stack of worlds where 
> it is up or the stack where it is down.The measurement leaks that information 
> via decoherence, and the worlds diverge irretrievably at that point.
> 
> 
> This is certainly a problem for Deutsch's interpretation of 'world'. Because 
> there are an infinite number of equivalent sets of basis vectors available 
> for every Hilbert space, it makes little sense to claim that an observer is 
> uncertain as to which basis he is in. He could choose any basis whatsoever. 
> But if he wants his choice to make sense in his lived life, he would be wise 
> to choose the basis that is singled out by decoherence as stable against 
> environmental degradation. In other words, he has to rely on decoherence to 
> solve the basis problem. Deutsch has no way of resolving the preferred basis 
> problem in his approach since, to him, all bases correspond to equivalent 
> 'worlds’.

That is why it is preferable to abandon the idea of “world” (an idea which BTW 
belongs more to metaphysics than physics) and use the “relative state”, or the 
“history” notions instead.

Decoherence is irreversible from inside the multiverse for the same reason that 
statistical physics is reversible, in Everett. The whole “universe” remains “in 
principle” reversible, bit not from inside, unless amnesia and 
ultra-sophisiticated technology (which doubtfully could ever exist).

Obviously, something like “the whole universe” is not yet definable, as this 
would need a quantum theory of gravity.

Bruno



> 
> Bruce
> 
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Re: Born's rule from almost nothing


> On 28 Jan 2021, at 02:07, Alan Grayson  wrote:
> 
> 
> 
> On Wednesday, January 27, 2021 at 9:20:15 AM UTC-7 Bruno Marchal wrote:
> 
>> On 17 Jan 2021, at 03:03, Pierz Newton-John > > wrote:
>> 
>> 
>> 
> 
>> On Sun, 17 Jan 2021 at 3:49 am, Alan Grayson > > wrote:
>> What would be the mechanism or process for other worlds to interact with 
>> each other, that is to interfere with each other? This is the gorilla in the 
>> room that many MWI enthusiasts ignore; awesome speculation with zero 
>> grounding in empirical evidence. Something definitely awry with this pov. AG
>> 
> 
>> I’m not an “enthusiast”. It’s a physical theory not a football team. If 
>> anything I dislike the idea of all those alternative variants of me and my 
>> life. If MWI is disproved I’ll be perfectly happy. It’s just that it 
>> unfortunately makes more sense in my assessment than any other alternative, 
>> so I entertain it as the most likely explanation for the observed data. To 
>> say it has zero grounding in empirical data is simply false  - it’s the 
>> theory that simply takes the empirical data to its logical conclusion 
>> without adding a collapse postulate. The wave function is the whole thing. 
>> Asking what the mechanism is for worlds to interfere with one another is the 
>> same as asking what the mechanism is for the Schrödinger wave function to 
>> interfere with itself. In the dual slit experiment it’s an observed fact. It 
>> makes no sense for it to behave that way if we stick to the old view of 
>> matter as little hard balls, but there you go. When we talk of “worlds”, it 
>> just refers to a ramifying quantum state, and it is in the nature of quantum 
>> states to interfere with themselves per the dual slit experiment, even if 
>> they become large and complex. Interference ceases when two branches of the 
>> universal quantum state diverge far enough that they completely decohere. 
>> When you say “what is the mechanism?” that really means “what is the 
>> mathematical description?” in physics. Anything else is just imprecise 
>> circumlocution like the word “world” in this context. So the mechanism for 
>> interference is the Schrödinger equation, which predicts such interference. 
>> MWI adds precisely nothing to that mathematical description.
> 
> 
> Yes. To avoid the MWI, the early founders of QM *added* an axiom: the wave 
> collapse postulate. But it introduce a non intelligible dualism with an 
> unknown theory of mind. It makes everything more complicated, for reason of 
> philosophical taste, which is alway dubious. Occam Razor favour the theory 
> with as much axioms as possible.
> 
> Especially if one believe in Mechanism. This asks us to believe that 2+2=4 & 
> Co., which entails the existence of all computations, with a extraordinary 
> complex redundancy of those computations, implying the existence of a 
> (Lebgues) Measure on their first person limit (the “observer” cannot be aware 
> of the number of steps of the universal dovetailing (which occur in all 
> models of any  theory of arithmetic). So ...
> 
> Bruno
> 
> Are irrational numbers, other than say PI or e, and possibly a few others, 
> computable? AG 


By Cantor theorem, the set of irrational numbers is non countable. The set of 
computable things is countable, so there are uncountably many irrational number 
which are not computable.

Some precise irrational numbers exists, like the one build from the 
characteristic function of non computable set, like the halting set (the set of 
code of non halting programs) or TOT (the set of code of total computable 
functions…).

In arithmetic most sets of numbers, including many having some use, are not 
computable.

In computer science, most attribute of programs are not computable. For 
example, there is no algorithm to decide if a given code compute the null 
function, or any function, actually. 

The computable part of mathematics is a very tiny part of mathematics.

Bruno





> 
> 
> 
>> 
>> 
>> On Saturday, January 16, 2021 at 9:32:49 AM UTC-7 Alan Grayson wrote:
>> On Saturday, January 16, 2021 at 1:23:52 AM UTC-7 Pierz wrote:
>> On Sat, 16 Jan 2021 at 2:18 pm, Alan Grayson > wrote:
>> 
>> 
>> On Friday, January 15, 2021 at 6:16:25 PM UTC-7 Pierz wrote:
>> On Sat, 16 Jan 2021 at 5:56 am, Alan Grayson > wrote:
>> 
>> 
>> On Thursday, January 14, 2021 at 11:36:39 PM UTC-7 Pierz wrote:
>> On Fri, 15 Jan 2021 at 4:01 pm, Alan Grayson > wrote:
>> 
>> 
>> On Thursday, January 14, 2021 at 3:15:47 PM UTC-7, Pierz wrote:
>> 
>> 
>> On Thursday, January 14, 2021 at 11:07:59 PM UTC+11 agrays...@gmail.com <> 
>> wrote:
>> On Thursday, January 14, 2021 at 2:26:42 AM UTC-7 Pierz wrote:
>> On Thursday, January 14, 2021 at 2:42:43 PM UTC+11 agrays...@gmail.com <> 
>> wrote:
>> On Wednesday, January 13, 2021 at 8:29:16 PM UTC-7 Pierz wrote:
>> On Thursday, January 14, 2021 at 1:23:11 PM UTC+11 agrays...@gmail.com <> 
>> wrote:
>> On Wednesday, January 13, 2021 at 4:33:20 PM UTC-7 Pierz wrote:
>>

Re: Born's rule from almost nothing


> On 25 Jan 2021, at 18:19, John Clark  wrote:
> 
> On Wed, Jan 20, 2021 at 2:59 PM 'Brent Meeker' via Everything List 
> mailto:everything-list@googlegroups.com>> 
> wrote:
> 
> >> Except for its simplicity the most important advantage of many worlds is 
> >> that it doesn't have to explain what "measured" means, or what a 
> >> "observer" means, or what a "choice" means because in many worlds ANY 
> >> physical change of any sort causes the Universe to split.
> 
> > That sounds like a bug not a feature. 
> 
> Well then, it should be easy for you to tell me exactly what  "measured" 
> means, and "observer" and "choice".
> 
> > Does every C14 decay in your body instantiate a different world?  Every 
> > photon that's absorbed by that chlorophyll molecule instead of that other 
> > molecule?
> 
> If the Many Worlds interpretation is correct then yes.  And before you bring 
> up Occam's razor let me remind you that it deals with the simplest 
> assumptions not the simplest conclusions. Many Worlds assumes Schrodinger's 
> Wave Equation means what it says. That's it. Hugh Everett did not assume that 
> many whirls exist, he concluded they did.
> 
> > As Bruno says, "World" and "Universe" become hard to define. 
> 
> That's extraordinarily easy to do in Many Worlds, as I said before ANY 
> physical change of any sort causes the Universe to split. If there has been 
> no change then there has been no split, and if there is a change then the 
> universe has split.

… at the speed of light. (Although even saying this is still a bit of a 
simplification). There is only relative state decohering into sets of parallel 
histories (which are actually more perpendicular than parallel …).



>  
> > you can't give meaning to "This"
> 
> The difficulty in the above is not with the word "this" it's with the word 
> "you".  
> 
>  > You need some way to talk about the quasi-classical world
> 
> Then "you", and all personal pronouns,  are a collection of very similar 
> beings living in very similar worlds. Yes, the definition is not precise and 
> is a bit fuzzy but that's the price you must pay if you insist on a  
> quasi-classical world definition in a Quantum Mechanical world.

Or use a good textbook in mathematical logic, which provides good definition of 
indexicals.


Bruno



> 
> > Bohr noted, that's where we live
> 
> I don't think Bohr ever said that, but if he did he was most certainly wrong. 
> We don't live in a classical world or even a quasi-classical one, although 
> sometimes we can pretend that we do if we only need approximate answers, but 
> sometimes we can't even get approximations that way even for practical 
> problems, such as those in solid-state physics; try explaining how your 
> pocket laser pointer works using nothing but classical ideas, and for 
> something like cosmology classical mechanics is completely hopeless.
> 
> John K Clark
> 
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Re: Born's rule from almost nothing

> On 27 Jan 2021, at 23:28, Bruce Kellett  wrote:
> 
> On Thu, Jan 28, 2021 at 3:08 AM Bruno Marchal  > wrote:
> 
> Also, worlds interfere statistically, by do not interact at all. A term in a 
> superposition cannot interact with any other terms, but we can make them 
> interfering, like with the two slits.
> 
> 
> Your grasp of the relevant physics is rather tenuous, I'm afraid Bruno.The 
> idea of "worlds interfering statistically without interacting" is just a 
> nonsense. There can only be interference if there is an interaction.

See Weinstein for good explanation on this, and a proof that if we allow 
interaction between, the “Everett world”, we violate thermodynamic and GR.

> And there certainly is an interaction between the photons on the two possible 
> paths in the two slit experiment. The two paths arrive at the screen with 
> different amplitudes and phases -- if the signs are the same, they add. But 
> if the signs are different they cancel -- partially or completely depending 
> on the relative amplitudes.

That is not a physical interaction between the photon(s). The amplitude 
concerne the wave, which describes the worlds/histories.

> 
> The trouble is that David Deutsch has really screwed up the understanding of 
> "worlds" for a lot of people.

I got the "Many-Words Interpretation” from Mechanism, and this for any physical 
reality compatible with mechanism, well before I knew anything on quantum 
mechanics.  Only later I got the formalism.
If you believe in 2+2=4 & Co, and in the Indexical Digital Mechanist 
hypothesis, the “many-worlds”, or better “the many histories” are unavoidable 
(where an history is a computation as seen from universal+ machine supported by 
that computation).

Then, if the founders dod not realise the MW aspect of quantum mechanics, they 
would not have invented a wave-collapse, which is trick to make them disappear. 
Everett showed just that we don’t need that trick, which is nice as it lead to 
many difficulties.

> He has talked as though each path in the two slit case is a separate "world", 
> and then has to resort to magic to reproduce the interference. The Everett 
> concept of a "world" is a "relative state", in which an "observer" sees a 
> definite result. This idea was made more precise with the introduction of the 
> idea of decoherence, and generalized entanglement with the environment. If 
> "worlds" are defined as the result of decoherent histories, then Deutsch's 
> confusion should not arise. A "world" is the result of (FAPP irreversible) 
> decoherence.

OK. Thanks to the quote for “world”.

> There is no decoherence at the slits in the two slit experiment, so no 
> separate "worlds" are formed.

But locally you do have a superposition of an history (going to this slit + 
going through the other slits), like in a quantum computer you can superpose 
different computations (and then make the result interning in a way such that a 
minimum of realism entails that you can understand that all computations have 
been performed.

> If you induce decoherence by measuring at the slits, then the interference 
> pattern disappears -- you have certainly created a separate "world" for each 
> path, but these can no longer interfere. That is part of the definition of 
> the "worlds" that are created by irreversible decoherence.

No problem.

> 
> So the concept of "world" is, indeed, well-defined in physics.

By giving a magic role to the observer, or its consciousness, or of 
measurement. The observer can no more be a machine in that picture.

> It might not be defined in logic or metaphysics, but this is of no concern to 
> the working physicist -- we know perfectly well what we mean by "a world”.

FAPP. OK.
The goal here is to try to understand what happens.

> And we can readily tell when someone is talking nonsense by claiming that 
> "worlds interfere statistically without interacting”.

? (That is rather standard, and pretty obvious, I would say).

> The superposition of the paths in the two slit case extends right to the 
> screen: that is what produces the interference -- superposition means that 
> the two components are added together with their intrinsic phases intact. If 
> you destroy the superposition at any point, such as by interacting with the 
> paths at the slits,

Nothing in the SWE allows anyone to destroy a superposition. We can only 
entangle the state with an unknown complex environment making the observation 
irreversible, but no superposition is physically destroyed. Even Bohr admitted 
this in his EPR answer to EPR.

> there is no more interference -- you have produced separate "worlds" that can 
> no longer interact so there is no interference. As Scott Aaronson is fond of 
> saying: quantum computers work by interference, so the computations must all 
> occur in one "world”.

But then that “one world” becomes a multiverse realising the many-histories.

> As Scott

Re: Born's rule from almost nothing


> On 25 Jan 2021, at 21:22, 'Brent Meeker' via Everything List 
>  wrote:
> 
> 
> 
> On 1/25/2021 5:39 AM, Alan Grayson wrote:
>> 
>> 
>> On Wednesday, January 20, 2021 at 12:59:02 PM UTC-7 Brent wrote:
>> 
>> 
>> On 1/20/2021 3:58 AM, John Clark wrote:
>>> On Wed, Jan 20, 2021 at 12:01 AM Alan Grayson >> > wrote:
>>> 
>>> >> No, there are NOT exactly 10 winners! There are an astronomical number 
>>> >> to an astronomical power number horses that won that race with only a 
>>> >> submicroscopic difference between them, and there are also an 
>>> >> astronomical number to an astronomical power number of Alan Graysons 
>>> >> that won his bet on that race.
>>> 
>>> > So instead of all possible outcomes being measured in some other world,
>>> 
>>> Except for its simplicity the most important advantage of many worlds is 
>>> that it doesn't have to explain what "measured" means, or what a "observer" 
>>> means, or what a "choice" means because in many worlds ANY physical change 
>>> of any sort causes the Universe to split.
>> 
>> That sounds like a bug not a feature.  Does every C14 decay in your body 
>> instantiate a different world?  Every photon that's absorbed by that 
>> chlorophyll molecule instead of that other molecule? As Bruno says, "World" 
>> and "Universe" become hard to define.  If you say "This universe." does it 
>> mean anything, even for a moment?  But it you can't give meaning to "This" 
>> how can you make sense of an experiment in which "This" evolves into "That"? 
>>  You need some way to talk about the quasi-classical world, because as Bohr 
>> noted, that's where we live and that's where science predicts things.
>> 
>> Brent
>> 
>> Now you know why I call the MWI "Trump Physics". Its advocates will never 
>> admit it's woefully wrong, like our hopefully departed "leader" who never 
>> admits a mistake.  Another example of this utter foolishness; note the 
>> numerous worlds created by ants which move along in repeated zig-zags. AG
> 
> I think you get entirely to worked up over it.  We have a theory that has a 
> huge domain of application.  Is predictive and extremely accurate.  The only 
> problem is the interpretation of the processes described by the mathematics.  
> Interpretations are not theories.  They are not right or wrong, because they 
> can't be tested.  W.V.O. Quine contributed to this confusion by saying that 
> ontology was the set of entities presupposed by our best theory.   That's a 
> philosopher's view.  I seems to make the questions of Hilbert space or 
> C*-algebra, discrete or continuous, Turing computable or not, into important 
> questions of what really, really exists.  That's the wrong attitude.  It's 
> the error of the misplaced concrete.  Feynmann had it right when he 
> said,"Every good physicists knows five different ways to express the same 
> physics in mathematics."  The function of interpretations is to suggest 
> better theories.  Better theories are ones with bigger domains and more 
> accurate predictions.  First we get better knowledge of facts; then we can 
> worry about the ontology later.  That's why I say epistemology precedes 
> ontology.

Epistemology precedes Ontology, epistemologically. OK, but Ontology precedes 
Epistemology ontologically. If not, the subject of knowledge becomes magical, 
somehow out of reality.

I almost agree with Quine here: the Fundamental Ontology (the ontology for a 
TOE) is given by the denotation of the terms of the fundamental theory that we 
have to assume if interested in the fundamental reality. To bad Quine was 
nominalist/physicalist.


> 
> Everett saw that there was a gap in QM.  Measurement wasn't really given a 
> physical description. The collapse of the wave function was just stuck in by 
> hand.  So he tried to fill it in.  This led to the study of decoherence and a 
> better theory of measurement.  It provides some definition of the Heisenberg 
> cut.  I think it still leaves a small gap.

… a big one, actually.


>   MWI advocates think it's complete. 

It is complete for physics, and physical prediction, but incomplete with 
respect to the relation between the prediction and the first person experience. 
Here Everett is using the “psycho-physico-parallelism, but by using mechanism, 
he has to justify the wave in a manner similar to his justification of the 
collapse appearance.


> But it's an interpretation...it's not true or false.  What will lead to 
> unification with gravity and spacetime is the interesting question.

For logician, an interpretation of a theory is a representation of the model of 
that theory in some other theories. Some interpretation can be made precise and 
tested. The cut between theories and interpretation is somehow arbitrary.

Bruno



> 
> Brent
> 
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Re: Born's rule from almost nothing


> On 20 Jan 2021, at 20:58, 'Brent Meeker' via Everything List 
>  wrote:
> 
> 
> 
> On 1/20/2021 3:58 AM, John Clark wrote:
>> On Wed, Jan 20, 2021 at 12:01 AM Alan Grayson > > wrote:
>> 
>> >> No, there are NOT exactly 10 winners! There are an astronomical number to 
>> >> an astronomical power number horses that won that race with only a 
>> >> submicroscopic difference between them, and there are also an 
>> >> astronomical number to an astronomical power number of Alan Graysons that 
>> >> won his bet on that race.
>> 
>> > So instead of all possible outcomes being measured in some other world,
>> 
>> Except for its simplicity the most important advantage of many worlds is 
>> that it doesn't have to explain what "measured" means, or what a "observer" 
>> means, or what a "choice" means because in many worlds ANY physical change 
>> of any sort causes the Universe to split.
> 
> That sounds like a bug not a feature.  Does every C14 decay in your body 
> instantiate a different world?  Every photon that's absorbed by that 
> chlorophyll molecule instead of that other molecule? As Bruno says, "World" 
> and "Universe" become hard to define.  If you say "This universe." does it 
> mean anything, even for a moment?  But it you can't give meaning to "This" 
> how can you make sense of an experiment in which "This" evolves into "That"?  
> You need some way to talk about the quasi-classical world, because as Bohr 
> noted, that's where we live and that's where science predicts things.

Indeed. And then the notion of “this” and “that”, and “me” and “other” is made 
clear by the discovery of the indexicals in arithmetic. Indeed Gödel proved 
incompleteness by translation “I am not provable” in pure arithmetic. The basic 
idea being rather simple: if D(’x”) gives 'x(‘x’)’, D(‘D’) give ‘D(‘D’)’. The 
only difficulty is in using a special “quote” function, allowing some quote 
variable to be instantiated. Recursion Theory solves that problem easily. 

Bruno



> 
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> 
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Re: Born's rule from almost nothing


> On 20 Jan 2021, at 06:01, Alan Grayson  wrote:
> 
> On Tuesday, January 19, 2021 at 11:46:35 AM UTC-7 johnk...@gmail.com wrote:
> On Tue, Jan 19, 2021 at 12:54 PM Alan Grayson  > wrote:
> 
> > So contrary to some who think I know zilch about the MWI, I DO know what 
> > world I am in ! It's the world in which I made my bet, and won or lost.
> 
> Assuming 30 seconds elapsed between the time you made your bet and the time 
> you won or lost your bet, which of those 30 * (5.39 × 10^44) splits that 
> occurred during that time interval is the one that "you" are in? And even if 
> by some miracle "you" could tell me which one "you" are in "now" that still 
> leaves open the question of if  "you" are still in that one "now". And if 
> "you" weren't in "that one" how could "you" tell the difference? 
>  
> > All other ALLEGED world are DERIVATIVE from this one, and I have zero 
> > contact
> 
> You keep saying that over and over again, but no matter how many times you 
> say it that won't make it true. Every world that exists has had contact with 
> each other in the past, they I'll have a common ancestor, they just won't 
> have any contact in the future.
> 
> How is this implied by the SWE? Isn't this an additional postulate of your 
> interpretation? AG  
> 
>  
>  
> > Also, since in the race there are exactly 10 possible winners,
> 
> No, there are NOT exactly 10 winners! There are an astronomical number to an 
> astronomical power number horses that won that race with only a 
> submicroscopic difference between them, and there are also an astronomical 
> number to an astronomical power number of Alan Graysons that won his bet on 
> that race.
> 
> So instead of all possible outcomes being measured in some other world, we 
> get a huge, possibly infinite occurrences of all possibilities being 
> measured. I can regard this as the extra postulate I have been asking about. 
> It must be additional since it doesn't seem implied by SWE. AG
> 
> > Why not avoid all this confusion and creation of worlds with zero energy 
> > sources, and accept that the wf collapses,
> 
> Because Schrodinger's Equation says nothing about the wave function 
> collapsing and nobody, except for Many Worlds, seems to be able to come up 
> with consistent coherent rules to tell us exactly when it collapses and when 
> it does not. And if you will not be happy until there is an explanation for 
> quantum mechanics that is not confusing and weird then I'm afraid you're 
> destined to be unhappy. G
> 
> You haven't answered my question; why is this interpretation more REASONABLE 
> or more CONSISTENT WITH OCCAM'S RAZOR compared to the collapse hypothesis 
> since gives it gives no clue whatever about the energy sources required to 
> create these other worlds? It seems to create hugely more problems than it 
> solves. AG


Energy is a statistical notion emerging INTERNALLY in most histories. The 
complete set of histories does not require any energy, no more than the set of 
all prime numbers, or the (constructive) set of all computations.

Bruno



> 
> Also, how does this interpretation tell us exactly WHEN the SWE collapses 
> since that occurs when the observer chooses to make the measurement? Nothing 
> to do with the SWE. All to do with the observer's behavior or choice. AG 
> 
>  John K Clark
> 
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Re: Born's rule from almost nothing

> On 19 Jan 2021, at 18:54, Alan Grayson  wrote:
> 
> 
> 
> On Tuesday, January 19, 2021 at 6:04:34 AM UTC-7 johnk...@gmail.com wrote:
> 
> On Sun, Jan 17, 2021 at 4:48 PM Alan Grayson  > wrote:
> 
>  And if Many Worlds is correct then there is an Alan Grayson for every 
>  horse in that race, and there is an Alan Grayson who saw every one of 
>  those horses win.  And if Many Worlds is not correct then something even 
>  stranger must be. The one thing we know for certain is that whatever 
>  quantum interpretation turns out to be true it's going to be weird, very 
>  very weird. 
> 
> >>> Obviously, a horse race isn't a quantum process,
> 
> >>You say it's obvious that you don't split because you'd feel it if you did,
> 
> > I never made that claim. But which split are you referring to?
> 
> You're asking me?! Which of the 5.39 * 10^44 splits that happen every second 
> are YOU referring to? 
> 
> > you guys have no clue what world your resident in
> 
> Yes, and that's why we can't make exact predictions, and that's why the 
> quantum world behaves so strangely. 
> 
> So contrary to some who think I know zilch about the MWI, I DO know what 
> world I am in !

Then you need to abandon the Mechanist hypothesis, and Darwin etc.

With the mechanist hypothesis, we can in principle duplicate you in 100 
numerically identical copies, put in different rooms; and you cannot know which 
rooms is supporting you. Then you can learn that you are indeed “duplicated” or 
“multiplied” by aleph_0 (at least!) in all models of elementary arithmetic. 

Even without mechanism, it is unclear how you could know which world you are 
in, or even if such world can make sense, but some hope remains. You still need 
to tell which theory of mind you are using.

> It's the world in which I made my bet, and won or lost.

This will only define an equivalence relation along (local) 
worlds/histories/computations.

> All other ALLEGED world are DERIVATIVE from this one, and I have zero contact 
> with them unless you have a postulate which asserts otherwise.

All computations exist independently of “you”. “This world” is a universal 
indexical idea available to all machines, but it never refer to a particular 
world. Using mechanism, that can be related to some version of Gödel-Löb 
incompleteness theorem.

> If you guys would make a bet, you'd have access to secret knowledge. Also, 
> since in the race there are exactly 10 possible winners, and you assert a 
> world comes into being for each winner, why do you assert so many worlds? Is 
> it because you're taking into account the varying positions of the horses as 
> the race progresses? Why not avoid all this confusion and creation of worlds 
> with zero energy sources, and accept that the wf collapses, and ceases to 
> apply when the race ends. AG

Because this enforces to describes observers by a theory violating quantum 
mechanics, and covariance, special relativity. It re-introduce dualism, without 
any intelligible theory of mind. All this to avoid the other worlds/histories?

> 
> John K Clark 

To be sure I was answering Grayson, here.

Bruno

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Re: Born's rule from almost nothing

> On 19 Jan 2021, at 15:44, Alina Gutoreva  wrote:
> 
> What if we include information processing (e.g., information gathering, 
> decision-making, communication, noise) into the equation? We all are kind of 
> split in terms of information.

Yes, that is the reasonable move, except that it leads to a counterintuitive 
picture of what any physical reality can be. If we assume the brain is Turing 
emulable, then physics is a derived notion from the mathematics of the 
indeterminacy of any person associated to any digital machines, which we know 
run (already) in (all) models of elementary arithmetic. The math confirms this 
as we find a quantum logic of alternate histories for the logic of the 
observable, defined (following thought experience, or Plotinus) by the logic of 
provable(p) & consistent(1=1) & p.

The problem of some Everretian seems to be relying to a “naïve conception” of 
world and of observer. 

Mechanism makes us duplicable (splittable) and we have to consider, to make any 
first person prediction of all histories/computations going through our mental 
states, and there is an infinity.

For a computationalist, Everett QM is a confirmation of the many-histories 
canonical and internal interpretation of elementary arithmetic (or of any 
universal machinery, in Turing-Church-Post-Kleene sense).

> 
> (considering to research quantum decision-making, so please let me know if 
> it’s a bad idea)

It is a good idea, but it is not directly related to decision. It is related to 
precision only as they are naturally related to prediction.

This makes physics into a branch of machine psychology (or slighlty more aptly: 
machine theology, as I have explained here from time to time).

Bruno

> 
> Ally
> 
> 
>> On 19 Jan 2021, at 13:03, John Clark > > wrote:
>> 
>> 
>> On Sun, Jan 17, 2021 at 4:48 PM Alan Grayson > > wrote:
>> 
>>  And if Many Worlds is correct then there is an Alan Grayson for every 
>>  horse in that race, and there is an Alan Grayson who saw every one of 
>>  those horses win.  And if Many Worlds is not correct then something 
>>  even stranger must be. The one thing we know for certain is that 
>>  whatever quantum interpretation turns out to be true it's going to be 
>>  weird, very very weird. 
>> 
>> >>> Obviously, a horse race isn't a quantum process,
>> 
>> >>You say it's obvious that you don't split because you'd feel it if you did,
>> 
>> > I never made that claim. But which split are you referring to?
>> 
>> You're asking me?! Which of the 5.39 * 10^44 splits that happen every second 
>> are YOU referring to? 
>> 
>> > you guys have no clue what world your resident in
>> 
>> Yes, and that's why we can't make exact predictions, and that's why the 
>> quantum world behaves so strangely. 
>> 
>> John K Clark 
>> 
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>> .
> 
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Re: Born's rule from almost nothing

2021-01-28 Thread Bruce Kellett

On Fri, Jan 29, 2021 at 3:01 AM smitra  wrote:

> On 28-01-2021 01:03, Bruce Kellett wrote:
> > On Thu, Jan 28, 2021 at 10:44 AM smitra  wrote:
> >
> >> FAPP, therefore not well defined at all. Sticking to FAPP you could
> >> never have discovered Special Relativity, General Relativity, found
> >> the
> >> correct way to resolve Maxwell's Demon paradox, etc. etc.
> >
> > FAPP is well-defined for all practical purposes. That is all that you
> > require for special and general relativity, statistical mechanics, and
> > the rest of physics. You cannot point me to any physical result that
> > is not FAPP -- we have only limited measurement precision, after all.
> > And that is good enough for real-world physics.
> >
> Lorentz transforms as interpreted by Lorentz himself, i.e. that there is
> one good frame defined by the ether that defines "the real time" was
> FAPP correct in 1905:
>
> https://www.youtube.com/watch?t=67=Et8-gg6XNDY
>
> You can also replace general relativity by an ugly post-Newtonian
> expansion of it and promote that to the FAPP correct theory.
>



Those examples do not show that the worlds resulting from decoherence are
not well-defined.

Bruce

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Re: Born's rule from almost nothing

2021-01-28 Thread smitra

On 28-01-2021 01:03, Bruce Kellett wrote:

On Thu, Jan 28, 2021 at 10:44 AM smitra wrote:

FAPP, therefore not well defined at all. Sticking to FAPP you could
never have discovered Special Relativity, General Relativity, found
the
correct way to resolve Maxwell's Demon paradox, etc. etc.

FAPP is well-defined for all practical purposes. That is all that you
require for special and general relativity, statistical mechanics, and
the rest of physics. You cannot point me to any physical result that
is not FAPP -- we have only limited measurement precision, after all.
And that is good enough for real-world physics.

Lorentz transforms as interpreted by Lorentz himself, i.e. that there is
one good frame defined by the ether that defines "the real time" was
FAPP correct in 1905:

https://www.youtube.com/watch?t=67=Et8-gg6XNDY

You can also replace general relativity by an ugly post-Newtonian
expansion of it and promote that to the FAPP correct theory.

Saibal

Bruce

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Re: Born's rule from almost nothing

2021-01-27 Thread 'Brent Meeker' via Everything List

On 1/27/2021 8:42 PM, Pierz Newton-John wrote:

On 28 Jan 2021, at 2:49 pm, 'Brent Meeker' via Everything List
wrote:

On 1/27/2021 5:11 PM, Pierz Newton-John wrote:

I’m not saying decoherence is reversible. I’ve corrected myself (or accepted your
correction) on that point. But my understanding of proposals for disconfirming MWI
involve extending quantum coherence to larger and larger scales. Deutsch has argued
that if we can get enough qubits into a quantum computation, we’ve effectively
“proved” MWI since “where did all that information come from?".

And Scott Aaronson has pointed out it all had to be in this world in order for
interference to produce an answer.

That argument rests on the definition of world as a decohered branch, and
Deutsch would not accept that definition.

Well, it's what everybody else means. If there's going to be
interference (and that's how quantum computer computes) then he must be
thinking that different components of a superposition count as different
worlds, e.g. when a |UP> sliver atom goes thru a horizontal SG then it
is in a superposition of |LEFT>+|RIGHT> and Deutsch wants to count those
as occurring in different worlds. But |UP> can be written as
superposition of left and right without the SG. It's just a choice of
basis.

Brent

I’m not sure if I agree with his argument, but I’m also not necessarily
convinced by that definition of “world”. I mean, it’s perfectly good as far as
it goes, but I’m not sure I’m happy with it being marshalled as an argument in
this way. If there is a world W which contains an electron in an up/down
superposition, then in the Deutsch picture, and I would say the Everett picture
in general, that means some observer in W is unaware of which world he/she is
in: the one where the electron is up or the one where it is down. Or rather
(and this is Deutsch not Everett), the stack of worlds where it is up or the
stack where it is down.The measurement leaks that information via decoherence,
and the worlds diverge irretrievably at that point.

Brent

Other proposals similarly involve reversibility at large scales. If QM is not
universal, then at some scale that will prove impossible not merely due to
technological limits, but limits of the laws of physics. If such a limit were
found, that would certainly disconfirm MWI.

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Re: Born's rule from almost nothing

On Thu, Jan 28, 2021 at 3:42 PM Pierz Newton-John  wrote:

> > On 28 Jan 2021, at 2:49 pm, 'Brent Meeker' via Everything List <
> everything-list@googlegroups.com> wrote:
> > On 1/27/2021 5:11 PM, Pierz Newton-John wrote:
> >> I’m not saying decoherence is reversible. I’ve corrected myself (or
> accepted your correction) on that point. But my understanding of proposals
> for disconfirming MWI involve extending quantum coherence to larger and
> larger scales. Deutsch has argued that if we can get enough qubits into a
> quantum computation, we’ve effectively “proved” MWI since “where did all
> that information come from?".
> >
> > And Scott Aaronson has pointed out it all had to be in this world in
> order for interference to produce an answer.
> >
> That argument rests on the definition of world as a decohered branch, and
> Deutsch would not accept that definition.

I agree. Deutsch has his own idiosyncratic definition that does not accord
with common usage. The trouble is that the word 'world' has an ordinary,
everyday use, and if you make a technical definition of something that is
quite different from the everyday meaning, but use the same word, you open
yourself to equivocation and invalid arguments.

Deutsch is using a technical definition of 'world' which corresponds to the
notion of a distinct basis for a particular Hilbert space. So, in his
terms, there are separate 'worlds' for every possible basis. In common
usage, the word 'world' is reserved for bases that are singled out by
decoherence as the preferred, stable bases. If you use the word 'world' for
any and  every one of the infinite number of possible bases for any given
Hilbert space, then you have deprived the word of any sensible referent or
meaning. The word 'branch' is likewise unavailable to Deutsch, because it
has a similar everyday meaning to 'world ' in this context. He could use
the term 'Hilbert space basis', but that robs his catch phrase of its
impact : "Quantum computers work because every possible calculation is
performed in some basis of the Hilbert space." Bases in Hilbert space do
not evidently have the same computational resources as other worlds. So
Deutsch's argument rests on an equivocation between the meanings of
'world'. His argument is patently invalid.

I’m not sure if I agree with his argument, but I’m also not necessarily
> convinced by that definition of “world”. I mean, it’s perfectly good as far
> as it goes, but I’m not sure I’m happy with it being marshalled as an
> argument in this way. If there is a world W which contains an electron in
> an up/down superposition, then in the Deutsch picture, and I would say the
> Everett picture in general, that means some observer in W is unaware of
> which world he/she is in: the one where the electron is up or the one where
> it is down. Or rather (and this is Deutsch not Everett), the stack of
> worlds where it is up or the stack where it is down.The measurement leaks
> that information via decoherence, and the worlds diverge irretrievably at
> that point.
>

This is certainly a problem for Deutsch's interpretation of 'world'.
Because there are an infinite number of equivalent sets of basis vectors
available for every Hilbert space, it makes little sense to claim that an
observer is uncertain as to which basis he is in. He could choose any basis
whatsoever. But if he wants his choice to make sense in his lived life, he
would be wise to choose the basis that is singled out by decoherence as
stable against environmental degradation. In other words, he has to rely on
decoherence to solve the basis problem. Deutsch has no way of resolving the
preferred basis problem in his approach since, to him, all bases correspond
to equivalent 'worlds'.

Bruce

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Re: Born's rule from almost nothing




> On 28 Jan 2021, at 2:49 pm, 'Brent Meeker' via Everything List 
>  wrote:
> 
> 
> 
> On 1/27/2021 5:11 PM, Pierz Newton-John wrote:
>> I’m not saying decoherence is reversible. I’ve corrected myself (or accepted 
>> your correction) on that point. But my understanding of proposals for 
>> disconfirming MWI involve extending quantum coherence to larger and larger 
>> scales. Deutsch has argued that if we can get enough qubits into a quantum 
>> computation, we’ve effectively “proved” MWI since “where did all that 
>> information come from?".
> 
> And Scott Aaronson has pointed out it all had to be in this world in order 
> for interference to produce an answer.
> 
That argument rests on the definition of world as a decohered branch, and 
Deutsch would not accept that definition. I’m not sure if I agree with his 
argument, but I’m also not necessarily convinced by that definition of “world”. 
I mean, it’s perfectly good as far as it goes, but I’m not sure I’m happy with 
it being marshalled as an argument in this way. If there is a world W which 
contains an electron in an up/down superposition, then in the Deutsch picture, 
and I would say the Everett picture in general, that means some observer in W 
is unaware of which world he/she is in: the one where the electron is up or the 
one where it is down. Or rather (and this is Deutsch not Everett), the stack of 
worlds where it is up or the stack where it is down.The measurement leaks that 
information via decoherence, and the worlds diverge irretrievably at that point.

> Brent
> 
>> Other proposals similarly involve reversibility at large scales. If QM is 
>> not universal, then at some scale that will prove impossible not merely due 
>> to technological limits, but limits of the laws of physics. If such a limit 
>> were found, that would certainly disconfirm MWI.
> 
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Re: Born's rule from almost nothing

2021-01-27 Thread 'Brent Meeker' via Everything List





On 1/27/2021 5:11 PM, Pierz Newton-John wrote:
I’m not saying decoherence is reversible. I’ve corrected myself (or 
accepted your correction) on that point. But my understanding of 
proposals for disconfirming MWI involve extending quantum coherence to 
larger and larger scales. Deutsch has argued that if we can get enough 
qubits into a quantum computation, we’ve effectively “proved” MWI 
since “where did all that information come from?".


And Scott Aaronson has pointed out it all had to be in this world in 
order for interference to produce an answer.


Brent

Other proposals similarly involve reversibility at large scales. If QM 
is not universal, then at some scale that will prove impossible not 
merely due to technological limits, but limits of the laws of physics. 
If such a limit were found, that would certainly disconfirm MWI.


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Re: Born's rule from almost nothing

On Thu, Jan 28, 2021 at 12:11 PM Pierz Newton-John 
wrote:

> On 28 Jan 2021, at 12:02 pm, Bruce Kellett  wrote:
>
>
> You can utilize technology to maintain quantum coherence over ever larger
> domains (as in quantum computers), but that domain can never extend to the
> whole universe; not even beyond the laboratory to the wider earth. This is
> not a technological limit -- the limit is in the laws of physics themselves.
>
> This actually has very little to do with the question of whether quantum
> physics is universal or not -- quantum mechanics can be the correct
> theory of everything in the universe, but it would still be the case that
> decoherence is irreversible in principle. This does not bear on the
> question whether Everett is correct or not.
>
>
> I’m not saying decoherence is reversible. I’ve corrected myself (or
> accepted your correction) on that point.
>

Good.

But my understanding of proposals for disconfirming MWI involve extending
> quantum coherence to larger and larger scales.
>

That is mistaken. The scale over which one can maintain quantum coherence
has no bearing on the truth or falsity of MWI.

Deutsch has argued that if we can get enough qubits into a quantum
> computation, we’ve effectively “proved” MWI since “where did all that
> information come from?".
>

Deutsch is simply wrong on this point. I know that he has been arguing that
quantum computers "prove" many worlds, "or else where did all the
computational power come from?". But other quantum computing experts, such
as Aaronson, disagree, and make the obvious point that quantum computers
work by interference, and interference necessarily all happens in this one
world -- separate worlds do not interfere.

Other proposals similarly involve reversibility at large scales. If QM is
> not universal, then at some scale that will prove impossible not merely due
> to technological limits, but limits of the laws of physics. If such a limit
> were found, that would certainly disconfirm MWI.
>

This is very confused. In principle irreversibility of quantum decoherence
occurs at all scales. As soon as some photons or air molecules hit the
laboratory walls from an experiment on any scale, there is irreversible
escape of thermal information to the wider environment, and ultimately to
IR photons out into space. The scale has nothing to do with quantum
universality, and such considerations can never confirm or disconfirm a
quantum interpretation, such as MWI.

Bruce

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Re: Born's rule from almost nothing



> On 28 Jan 2021, at 12:02 pm, Bruce Kellett  wrote:
> 
> On Thu, Jan 28, 2021 at 11:47 AM Pierz Newton-John  > wrote:
> On 28 Jan 2021, at 11:32 am, Bruce Kellett  > wrote:
>> On Thu, Jan 28, 2021 at 11:20 AM Pierz Newton-John > > wrote:
>> On 28 Jan 2021, at 11:03 am, Bruce Kellett > > wrote:
>>> On Thu, Jan 28, 2021 at 10:44 AM smitra >> > wrote:
>>> 
>>> FAPP, therefore not well defined at all. Sticking to FAPP you could 
>>> never have discovered Special Relativity, General Relativity, found the 
>>> correct way to resolve Maxwell's Demon paradox, etc. etc.
>>> 
>>> FAPP is well-defined for all practical purposes. That is all that you 
>>> require for special and general relativity, statistical mechanics, and the 
>>> rest of physics. You cannot point me to any physical result that is not 
>>> FAPP -- we have only limited measurement precision, after all. And that is 
>>> good enough for real-world physics.
>>> 
>> Bruno’s point IIUC is that FAPP is OK for the physics you have now, but 
>> possibly not for the next physics. "Irreversible FAPP” means irreversible 
>> today. It’s true that there does come a point with decoherence where the 
>> state is irreversible, but that point is arbitrary and depends on the 
>> technology you have available.
>> 
>> That is not true. Decoherence ultimately involves the emission of IR photons 
>> into outerspace -- through heat dissipated in the atmosphere if no other 
>> way. Such effects are truely irreversible, not just FAPP, because once you 
>> have lost photons to space there is no way to get them back -- you can't 
>> chase after them and turn them around.
>> 
>> The point about decoherence is that the irreversibility is ultimately a 
>> matter of the laws of physics. FAPP is just for laboratory purposes, but in 
>> the wider context, the irreversibility is absolute, not just FAPP.
> 
> That’s true - decoherence by definition means something escaped the 
> experimental boundaries and then it’s game over.  I should have said that 
> where decoherence begins is technologically determined.
> 
> That is not really true. Decoherence begins with the interaction with 
> environmental degrees of freedom. If you limit this interaction 
> technologically, then you might be able to reverse things in particular 
> cases, but that does not really prove anything because, as I have pointed out 
> in the general case, the interaction with the environmentultimately produces 
> heat, and some of that escapes to outer space. You can't travel faster than 
> these IR photons rto turn them round, or harvest them. So the laws of physics 
> themselves, relativity and thermodynamics, mandate that quantum events are in 
> general irreversible.
> 
> You can utilize technology to maintain quantum coherence over ever larger 
> domains (as in quantum computers), but that domain can never extend to the 
> whole universe; not even beyond the laboratory to the wider earth. This is 
> not a technological limit -- the limit is in the laws of physics themselves.
> 
> This actually has very little to do with the question of whether quantum 
> physics is universal or not -- quantum mechanics can be the correct theory of 
> everything in the universe, but it would still be the case that decoherence 
> is irreversible in principle. This does not bear on the question whether 
> Everett is correct or not.

I’m not saying decoherence is reversible. I’ve corrected myself (or accepted 
your correction) on that point. But my understanding of proposals for 
disconfirming MWI involve extending quantum coherence to larger and larger 
scales. Deutsch has argued that if we can get enough qubits into a quantum 
computation, we’ve effectively “proved” MWI since “where did all that 
information come from?". Other proposals similarly involve reversibility at 
large scales. If QM is not universal, then at some scale that will prove 
impossible not merely due to technological limits, but limits of the laws of 
physics. If such a limit were found, that would certainly disconfirm MWI. 

> 
> Bruce
> 
>  
> The point is that the bounds of what is reversible or not depend on what we 
> are  technologically capable of. After all that’s the problem of quantum 
> computers - maintaining larger and larger superpositions in a controlled 
> state. In the future it’s to be hoped that we can extend those bounds to the 
> point where the question of whether QM is universal or not can be resolved. 
> Surely that is a meaningful question and surely the only way to answer it is 
> through something like what I am describing. If we can be confident that QM 
> is universal, then we can get closer to an answer on whether MWI is the right 
> interpretation.
> 
> -- 
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> Groups "Everything List" group.
> To

Re: Born's rule from almost nothing



On Wednesday, January 27, 2021 at 9:20:15 AM UTC-7 Bruno Marchal wrote:

>
> On 17 Jan 2021, at 03:03, Pierz Newton-John  wrote:
>
>
>
> On Sun, 17 Jan 2021 at 3:49 am, Alan Grayson  wrote:
>
>> *What would be the mechanism or process for other worlds to interact with 
>> each other, that is to interfere with each other? This is the gorilla in 
>> the room that many MWI enthusiasts ignore; awesome speculation with zero 
>> grounding in empirical evidence. Something definitely awry with this pov. 
>> AG*
>
>
> I’m not an “enthusiast”. It’s a physical theory not a football team. If 
> anything I dislike the idea of all those alternative variants of me and my 
> life. If MWI is disproved I’ll be perfectly happy. It’s just that it 
> unfortunately makes more sense in my assessment than any other alternative, 
> so I entertain it as the most likely explanation for the observed data. To 
> say it has zero grounding in empirical data is simply false  - it’s the 
> theory that simply takes the empirical data to its logical conclusion 
> without adding a collapse postulate. The wave function is the whole thing. 
> Asking what the mechanism is for worlds to interfere with one another is 
> the same as asking what the mechanism is for the Schrödinger wave function 
> to interfere with itself. In the dual slit experiment it’s an observed 
> fact. It makes no sense for it to behave that way if we stick to the old 
> view of matter as little hard balls, but there you go. When we talk of 
> “worlds”, it just refers to a ramifying quantum state, and it is in the 
> nature of quantum states to interfere with themselves per the dual slit 
> experiment, even if they become large and complex. Interference ceases when 
> two branches of the universal quantum state diverge far enough that they 
> completely decohere. When you say “what is the mechanism?” that really 
> means “what is the mathematical description?” in physics. Anything else is 
> just imprecise circumlocution like the word “world” in this context. So the 
> mechanism for interference is the Schrödinger equation, which predicts such 
> interference. MWI adds precisely nothing to that mathematical description.
>
>
>
> Yes. To avoid the MWI, the early founders of QM *added* an axiom: the wave 
> collapse postulate. But it introduce a non intelligible dualism with an 
> unknown theory of mind. It makes everything more complicated, for reason of 
> philosophical taste, which is alway dubious. Occam Razor favour the theory 
> with as much axioms as possible.
>
> Especially if one believe in Mechanism. This asks us to believe that 2+2=4 
> & Co., which entails the existence of all computations, with a 
> extraordinary complex redundancy of those computations, implying the 
> existence of a (Lebgues) Measure on their first person limit (the 
> “observer” cannot be aware of the number of steps of the universal 
> dovetailing (which occur in all models of any  theory of arithmetic). So ...
>
> Bruno
>

*Are irrational numbers, other than say PI or e, and possibly a few others, 
computable? AG *

>
>
>
>>
>> On Saturday, January 16, 2021 at 9:32:49 AM UTC-7 Alan Grayson wrote:
>>
>>> On Saturday, January 16, 2021 at 1:23:52 AM UTC-7 Pierz wrote:
>>>
 On Sat, 16 Jan 2021 at 2:18 pm, Alan Grayson  
 wrote:

>
>
> On Friday, January 15, 2021 at 6:16:25 PM UTC-7 Pierz wrote:
>
>> On Sat, 16 Jan 2021 at 5:56 am, Alan Grayson  
>> wrote:
>>
>>>
>>>
>>> On Thursday, January 14, 2021 at 11:36:39 PM UTC-7 Pierz wrote:
>>>
 On Fri, 15 Jan 2021 at 4:01 pm, Alan Grayson  
 wrote:

>
>
> On Thursday, January 14, 2021 at 3:15:47 PM UTC-7, Pierz wrote:
>>
>>
>>
>> On Thursday, January 14, 2021 at 11:07:59 PM UTC+11 
>> agrays...@gmail.com wrote:
>>
>>> On Thursday, January 14, 2021 at 2:26:42 AM UTC-7 Pierz wrote:
>>>
 On Thursday, January 14, 2021 at 2:42:43 PM UTC+11 
 agrays...@gmail.com wrote:

> On Wednesday, January 13, 2021 at 8:29:16 PM UTC-7 Pierz wrote:
>
>> On Thursday, January 14, 2021 at 1:23:11 PM UTC+11 
>> agrays...@gmail.com wrote:
>>
>>> On Wednesday, January 13, 2021 at 4:33:20 PM UTC-7 Pierz 
>>> wrote:
>>>
 On Wednesday, January 13, 2021 at 5:50:29 PM UTC+11 
 agrays...@gmail.com wrote:

> On Tuesday, January 12, 2021 at 10:19:59 PM UTC-7 Pierz 
> wrote:
>
>>
>>
>> On Monday, January 4, 2021 at 12:09:06 PM UTC+11 
>> agrays...@gmail.com wrote:
>>
>>> On Sunday, January 3, 2021 at 3:56:51 PM UTC-7 
>>> johnk...@gmail.com wrote:
>>>

Re: Born's rule from almost nothing

On Thu, Jan 28, 2021 at 11:47 AM Pierz Newton-John 
wrote:

> On 28 Jan 2021, at 11:32 am, Bruce Kellett  wrote:
>
> On Thu, Jan 28, 2021 at 11:20 AM Pierz Newton-John 
> wrote:
>
>> On 28 Jan 2021, at 11:03 am, Bruce Kellett  wrote:
>>
>> On Thu, Jan 28, 2021 at 10:44 AM smitra  wrote:
>>
>>>
>>> FAPP, therefore not well defined at all. Sticking to FAPP you could
>>> never have discovered Special Relativity, General Relativity, found the
>>> correct way to resolve Maxwell's Demon paradox, etc. etc.
>>>
>>
>> FAPP is well-defined for all practical purposes. That is all that you
>> require for special and general relativity, statistical mechanics, and the
>> rest of physics. You cannot point me to any physical result that is not
>> FAPP -- we have only limited measurement precision, after all. And that is
>> good enough for real-world physics.
>>
>> Bruno’s point IIUC is that FAPP is OK for the physics you have now, but
>> possibly not for the next physics. "Irreversible FAPP” means irreversible
>> today. It’s true that there does come a point with decoherence where the
>> state is irreversible, but that point is arbitrary and depends on the
>> technology you have available.
>>
>
> That is not true. Decoherence ultimately involves the emission of IR
> photons into outerspace -- through heat dissipated in the atmosphere if no
> other way. Such effects are truely irreversible, not just FAPP, because
> once you have lost photons to space there is no way to get them back -- you
> can't chase after them and turn them around.
>
> The point about decoherence is that the irreversibility is ultimately a
> matter of the laws of physics. FAPP is just for laboratory purposes, but in
> the wider context, the irreversibility is absolute, not just FAPP.
>
>
> That’s true - decoherence by definition means something escaped the
> experimental boundaries and then it’s game over.  I should have said that
> where decoherence begins is technologically determined.
>

That is not really true. Decoherence begins with the interaction with
environmental degrees of freedom. If you limit this interaction
technologically, then you might be able to reverse things in particular
cases, but that does not really prove anything because, as I have pointed
out in the general case, the interaction with the
environmentultimately produces heat, and some of that escapes to outer
space. You can't travel faster than these IR photons rto turn them round,
or harvest them. So the laws of physics themselves, relativity and
thermodynamics, mandate that quantum events are in general irreversible.

You can utilize technology to maintain quantum coherence over ever larger
domains (as in quantum computers), but that domain can never extend to the
whole universe; not even beyond the laboratory to the wider earth. This is
not a technological limit -- the limit is in the laws of physics themselves.

This actually has very little to do with the question of whether quantum
physics is universal or not -- quantum mechanics can be the correct
theory of everything in the universe, but it would still be the case that
decoherence is irreversible in principle. This does not bear on the
question whether Everett is correct or not.

Bruce

> The point is that the bounds of what is reversible or not depend on what
> we are  technologically capable of. After all that’s the problem of quantum
> computers - maintaining larger and larger superpositions in a controlled
> state. In the future it’s to be hoped that we can extend those bounds to
> the point where the question of whether QM is universal or not can be
> resolved. Surely that is a meaningful question and surely the only way to
> answer it is through something like what I am describing. If we can be
> confident that QM is universal, then we can get closer to an answer on
> whether MWI is the right interpretation.
>

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Re: Born's rule from almost nothing



> On 28 Jan 2021, at 11:32 am, Bruce Kellett  wrote:
> 
> On Thu, Jan 28, 2021 at 11:20 AM Pierz Newton-John  > wrote:
> On 28 Jan 2021, at 11:03 am, Bruce Kellett  > wrote:
>> On Thu, Jan 28, 2021 at 10:44 AM smitra > > wrote:
>> 
>> FAPP, therefore not well defined at all. Sticking to FAPP you could 
>> never have discovered Special Relativity, General Relativity, found the 
>> correct way to resolve Maxwell's Demon paradox, etc. etc.
>> 
>> FAPP is well-defined for all practical purposes. That is all that you 
>> require for special and general relativity, statistical mechanics, and the 
>> rest of physics. You cannot point me to any physical result that is not FAPP 
>> -- we have only limited measurement precision, after all. And that is good 
>> enough for real-world physics.
>> 
> Bruno’s point IIUC is that FAPP is OK for the physics you have now, but 
> possibly not for the next physics. "Irreversible FAPP” means irreversible 
> today. It’s true that there does come a point with decoherence where the 
> state is irreversible, but that point is arbitrary and depends on the 
> technology you have available.
> 
> That is not true. Decoherence ultimately involves the emission of IR photons 
> into outerspace -- through heat dissipated in the atmosphere if no other way. 
> Such effects are truely irreversible, not just FAPP, because once you have 
> lost photons to space there is no way to get them back -- you can't chase 
> after them and turn them around.
> 
> The point about decoherence is that the irreversibility is ultimately a 
> matter of the laws of physics. FAPP is just for laboratory purposes, but in 
> the wider context, the irreversibility is absolute, not just FAPP.

That’s true - decoherence by definition means something escaped the 
experimental boundaries and then it’s game over.  I should have said that where 
decoherence begins is technologically determined. The point is that the bounds 
of what is reversible or not depend on what we are  technologically capable of. 
After all that’s the problem of quantum computers - maintaining larger and 
larger superpositions in a controlled state. In the future it’s to be hoped 
that we can extend those bounds to the point where the question of whether QM 
is universal or not can be resolved. Surely that is a meaningful question and 
surely the only way to answer it is through something like what I am 
describing. If we can be confident that QM is universal, then we can get closer 
to an answer on whether MWI is the right interpretation.
> 
> 
> Proposals for testing MWI involve extending that point further and further. 
> If you can reverse a quantum state that has evolved to macroscopic 
> complexity, you can get interference and you’re on your way to showing that 
> QM is indeed universal, and that MWI may be the best theory. FAPP is just 
> giving up on testing, say, the Frauchiger-Renner experiment, which may prove 
> to be tomorrow's equivalent of testing Bell’s theorem - not possible when the 
> theorem was created, but possible later on.
> 
> I think you have failed to understand the physics underlying FAPP. It is not 
> just a matter of technology. FAPP is for laboratory convenience, but 
> ultimately, the irreversibility is built into the laws of physics.
> 
> Bruce
> 
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>  
> .

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Re: Born's rule from almost nothing

On Thu, Jan 28, 2021 at 11:20 AM Pierz Newton-John 
wrote:

> On 28 Jan 2021, at 11:03 am, Bruce Kellett  wrote:
>
> On Thu, Jan 28, 2021 at 10:44 AM smitra  wrote:
>
>>
>> FAPP, therefore not well defined at all. Sticking to FAPP you could
>> never have discovered Special Relativity, General Relativity, found the
>> correct way to resolve Maxwell's Demon paradox, etc. etc.
>>
>
> FAPP is well-defined for all practical purposes. That is all that you
> require for special and general relativity, statistical mechanics, and the
> rest of physics. You cannot point me to any physical result that is not
> FAPP -- we have only limited measurement precision, after all. And that is
> good enough for real-world physics.
>
> Bruno’s point IIUC is that FAPP is OK for the physics you have now, but
> possibly not for the next physics. "Irreversible FAPP” means irreversible
> today. It’s true that there does come a point with decoherence where the
> state is irreversible, but that point is arbitrary and depends on the
> technology you have available.
>

That is not true. Decoherence ultimately involves the emission of IR
photons into outerspace -- through heat dissipated in the atmosphere if no
other way. Such effects are truely irreversible, not just FAPP, because
once you have lost photons to space there is no way to get them back -- you
can't chase after them and turn them around.

The point about decoherence is that the irreversibility is ultimately a
matter of the laws of physics. FAPP is just for laboratory purposes, but in
the wider context, the irreversibility is absolute, not just FAPP.


Proposals for testing MWI involve extending that point further and further.
> If you can reverse a quantum state that has evolved to macroscopic
> complexity, you can get interference and you’re on your way to showing that
> QM is indeed universal, and that MWI may be the best theory. FAPP is just
> giving up on testing, say, the Frauchiger-Renner experiment, which may
> prove to be tomorrow's equivalent of testing Bell’s theorem - not possible
> when the theorem was created, but possible later on.
>

I think you have failed to understand the physics underlying FAPP. It is
not just a matter of technology. FAPP is for laboratory convenience, but
ultimately, the irreversibility is built into the laws of physics.

Bruce

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Re: Born's rule from almost nothing

> On 28 Jan 2021, at 11:03 am, Bruce Kellett  wrote:
> 
> On Thu, Jan 28, 2021 at 10:44 AM smitra  > wrote:
> 
> FAPP, therefore not well defined at all. Sticking to FAPP you could 
> never have discovered Special Relativity, General Relativity, found the 
> correct way to resolve Maxwell's Demon paradox, etc. etc.
> 
> FAPP is well-defined for all practical purposes. That is all that you require 
> for special and general relativity, statistical mechanics, and the rest of 
> physics. You cannot point me to any physical result that is not FAPP -- we 
> have only limited measurement precision, after all. And that is good enough 
> for real-world physics.
> 

Bruno’s point IIUC is that FAPP is OK for the physics you have now, but 
possibly not for the next physics. "Irreversible FAPP” means irreversible 
today. It’s true that there does come a point with decoherence where the state 
is irreversible, but that point is arbitrary and depends on the technology you 
have available. Proposals for testing MWI involve extending that point further 
and further. If you can reverse a quantum state that has evolved to macroscopic 
complexity, you can get interference and you’re on your way to showing that QM 
is indeed universal, and that MWI may be the best theory. FAPP is just giving 
up on testing, say, the Frauchiger-Renner experiment, which may prove to be 
tomorrow's equivalent of testing Bell’s theorem - not possible when the theorem 
was created, but possible later on.

> Bruce
> 
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>  
> .

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Re: Born's rule from almost nothing

On Thu, Jan 28, 2021 at 10:44 AM smitra  wrote:

>
> FAPP, therefore not well defined at all. Sticking to FAPP you could
> never have discovered Special Relativity, General Relativity, found the
> correct way to resolve Maxwell's Demon paradox, etc. etc.
>

FAPP is well-defined for all practical purposes. That is all that you
require for special and general relativity, statistical mechanics, and the
rest of physics. You cannot point me to any physical result that is not
FAPP -- we have only limited measurement precision, after all. And that is
good enough for real-world physics.

Bruce

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Re: Born's rule from almost nothing

On Thu, Jan 28, 2021 at 10:46 AM 'Brent Meeker' via Everything List <
everything-list@googlegroups.com> wrote:

> On 1/27/2021 3:06 PM, Bruce Kellett wrote:
>
> On Thu, Jan 28, 2021 at 9:51 AM 'Brent Meeker' via Everything List <
> everything-list@googlegroups.com> wrote:
>
>> On 1/27/2021 2:28 PM, Bruce Kellett wrote:
>>
>> On Thu, Jan 28, 2021 at 3:08 AM Bruno Marchal  wrote:
>>
>>>
>>> Also, worlds interfere statistically, by do not interact at all. A term
>>> in a superposition cannot interact with any other terms, but we can make
>>> them interfering, like with the two slits.
>>>
>>
>>
>> Your grasp of the relevant physics is rather tenuous, I'm afraid Bruno.
>> The idea of "worlds interfering statistically without interacting" is just
>> a nonsense.  There can only be interference if there is an interaction. And
>> there certainly is an interaction between the photons on the two possible
>> paths in the two slit experiment. The two paths arrive at the screen with
>> different amplitudes and phases -- if the signs are the same, they add. But
>> if the signs are different they cancel -- partially or completely depending
>> on the relative amplitudes.
>>
>> The trouble is that David Deutsch has really screwed up the understanding
>> of "worlds" for a lot of people. He has talked as though each path in the
>> two slit case is a separate "world", and then has to resort to magic to
>> reproduce the interference. The Everett concept of a "world" is a "relative
>> state", in which an "observer" sees a definite result. This idea was made
>> more precise with the introduction of the idea of decoherence, and
>> generalized entanglement with the environment. If "worlds" are defined as
>> the result of decoherent histories, then Deutsch's confusion should not
>> arise. A "world" is the result of (FAPP irreversible) decoherence. There is
>> no decoherence at the slits in the two slit experiment, so no separate
>> "worlds" are formed. If you induce decoherence by measuring at the slits,
>> then the interference pattern disappears -- you have certainly created a
>> separate "world" for each path, but these can no longer interfere. That is
>> part of the definition of the "worlds" that are created by irreversible
>> decoherence.
>>
>>
>> That's where I think there is still a gap in the theory.  We know that in
>> the C60 double slit experiment the interference is wiped out because
>> sufficiently short wavelength IR photons from the buckyballs record their
>> position in the environment, presumably when they are absorbed in the
>> laboratory walls.  But what would happen if they weren't registered any
>> where.  What if the experiment were in outer space and the IR photons just
>> went off into infinity in a spherically symmetric wavefunction that never
>> "collapsed"?
>>
>
>
> I thought that was answered in one of Zeilinger's delayed choice
> experiments.  The idler photons that carry the 'welcher weg' information do
> not have to be measured or intercepted. As long as they exist anywhere in
> the universe, the interference is destroyed. You have to actually 'quantum
> erase' the 'welcher weg' information they carry in order to restore the
> interference.
>
>
> As I recall, the experiment showed that you could erase the welcher weg
> information *after *the Young's slits photons were already recorded,  but
> there was no test of not registering them at all...which is understandably
> hard to arrange.  That's why I had to postulate an experiment in outer
> space.  I suppose you could interpret the experiment as saying welcher weg
> photons flying off into space will be registered somewhere sometime and
> certainly won't have their information erased and so the experiment shows
> that the interference pattern would be wiped out.  But it's not actually
> true that the idler photons will necessarily be registered somewhere
> sometime.  We see photons from the CMB.   So photons can just get
> redshifted so far that they no longer carry the necessary information.
>

I am not so sure that they didn't test the possibility of not registering
the welcher weg photons at all. Calibration runs in which these photons are
not detected always lead to the loss of interference. Photons interact only
weakly with each other and with the atmosphere (and open space). That is
why photons are useful for these experiments -- they don't lose coherence
all that easily. So sending them out the window aimed at the sky is
effectively to not ever detect them. The reddening due to the expansion of
the universe does not destroy the information -- radio waves can still be
polarized/detected or whatever.

Bruce

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Re: Born's rule from almost nothing

2021-01-27 Thread 'Brent Meeker' via Everything List




On 1/27/2021 3:06 PM, Bruce Kellett wrote:
On Thu, Jan 28, 2021 at 9:51 AM 'Brent Meeker' via Everything List 
> wrote:


On 1/27/2021 2:28 PM, Bruce Kellett wrote:

On Thu, Jan 28, 2021 at 3:08 AM Bruno Marchal mailto:marc...@ulb.ac.be>> wrote:


Also, worlds interfere statistically, by do not interact at
all. A term in a superposition cannot interact with any other
terms, but we can make them interfering, like with the two slits.



Your grasp of the relevant physics is rather tenuous, I'm afraid
Bruno. The idea of "worlds interfering statistically without
interacting" is just a nonsense.  There can only be interference
if there is an interaction. And there certainly is an interaction
between the photons on the two possible paths in the two slit
experiment. The two paths arrive at the screen with different
amplitudes and phases -- if the signs are the same, they add. But
if the signs are different they cancel -- partially or
completely depending on the relative amplitudes.

The trouble is that David Deutsch has really screwed up the
understanding of "worlds" for a lot of people. He has talked as
though each path in the two slit case is a separate "world", and
then has to resort to magic to reproduce the interference. The
Everett concept of a "world" is a "relative state", in which an
"observer" sees a definite result. This idea was made more
precise with the introduction of the idea of decoherence, and
generalized entanglement with the environment. If "worlds" are
defined as the result of decoherent histories, then Deutsch's
confusion should not arise. A "world" is the result of (FAPP
irreversible) decoherence. There is no decoherence at the slits
in the two slit experiment, so no separate "worlds" are formed.
If you induce decoherence by measuring at the slits, then the
interference pattern disappears -- you have certainly created a
separate "world" for each path, but these can no longer
interfere. That is part of the definition of the "worlds" that
are created by irreversible decoherence.


That's where I think there is still a gap in the theory. We know
that in the C60 double slit experiment the interference is wiped
out because sufficiently short wavelength IR photons from the
buckyballs record their position in the environment, presumably
when they are absorbed in the laboratory walls.  But what would
happen if they weren't registered any where.  What if the
experiment were in outer space and the IR photons just went off
into infinity in a spherically symmetric wavefunction that never
"collapsed"?



I thought that was answered in one of Zeilinger's delayed choice 
experiments.  The idler photons that carry the 'welcher weg' 
information do not have to be measured or intercepted. As long as they 
exist anywhere in the universe, the interference is destroyed. You 
have to actually 'quantum erase' the 'welcher weg' information they 
carry in order to restore the interference.


As I recall, the experiment showed that you could erase the welcher weg 
information /after /the Young's slits photons were already recorded,  
but there was no test of not registering them at all...which is 
understandably hard to arrange.  That's why I had to postulate an 
experiment in outer space.  I suppose you could interpret the experiment 
as saying welcher weg photons flying off into space will be registered 
somewhere sometime and certainly won't have their information erased and 
so the experiment shows that the interference pattern would be wiped 
out.  But it's not actually true that the idler photons will necessarily 
be registered somewhere sometime.  We see photons from the CMB.   So 
photons can just get redshifted so far that they no longer carry the 
necessary information.



Running the idler photons into the wall is not quantum erasure.


I think I explicitly said that.

Brent



Bruce


So the concept of "world" is, indeed, well-defined in physics. It
might not be defined in logic or metaphysics, but this is of no
concern to the working physicist -- we know perfectly well what
we mean by "a world". And we can readily tell when someone is
talking nonsense by claiming that "worlds interfere statistically
without interacting". The superposition of the paths in the two
slit case extends right to the screen: that is what produces the
interference -- superposition means that the two components are
added together with their intrinsic phases intact. If you destroy
the superposition at any point, such as by interacting with the
paths at the slits, there is no more interference -- you have
produced separate "worlds" that can no longer interact so there
is no interference. As Scott Aaronson is fond of saying: quantum
computers work by

Re: Born's rule from almost nothing

2021-01-27 Thread smitra

On 27-01-2021 23:28, Bruce Kellett wrote:

On Thu, Jan 28, 2021 at 3:08 AM Bruno Marchal
wrote:

Also, worlds interfere statistically, by do not interact at all. A
term in a superposition cannot interact with any other terms, but we
can make them interfering, like with the two slits.

Your grasp of the relevant physics is rather tenuous, I'm afraid
Bruno. The idea of "worlds interfering statistically without
interacting" is just a nonsense. There can only be interference if
there is an interaction. And there certainly is an interaction between
the photons on the two possible paths in the two slit experiment. The
two paths arrive at the screen with different amplitudes and phases --
if the signs are the same, they add. But if the signs are different
they cancel -- partially or completely depending on the relative
amplitudes.

The trouble is that David Deutsch has really screwed up the
understanding of "worlds" for a lot of people. He has talked as though
each path in the two slit case is a separate "world", and then has to
resort to magic to reproduce the interference. The Everett concept of
a "world" is a "relative state", in which an "observer" sees a
definite result. This idea was made more precise with the introduction
of the idea of decoherence, and generalized entanglement with the
environment. If "worlds" are defined as the result of decoherent
histories, then Deutsch's confusion should not arise. A "world" is the
result of (FAPP irreversible) decoherence. There is no decoherence at
the slits in the two slit experiment, so no separate "worlds" are
formed. If you induce decoherence by measuring at the slits, then the
interference pattern disappears -- you have certainly created a
separate "world" for each path, but these can no longer interfere.
That is part of the definition of the "worlds" that are created by
irreversible decoherence.

So the concept of "world" is, indeed, well-defined in physics. It
might not be defined in logic or metaphysics, but this is of no
concern to the working physicist -- we know perfectly well what we
mean by "a world". And we can readily tell when someone is talking
nonsense by claiming that "worlds interfere statistically without
interacting". The superposition of the paths in the two slit case
extends right to the screen: that is what produces the interference --
superposition means that the two components are added together with
their intrinsic phases intact. If you destroy the superposition at any
point, such as by interacting with the paths at the slits, there is no
more interference -- you have produced separate "worlds" that can no
longer interact so there is no interference. As Scott Aaronson is fond
of saying: quantum computers work by interference, so the computations
must all occur in one "world". As Scott recently posted: "BREAKING:
President Biden signs executive order banning people from saying
"Quantum computers solve problems by just trying all possible
solutions in parallel"."

FAPP, therefore not well defined at all. Sticking to FAPP you could
never have discovered Special Relativity, General Relativity, found the
correct way to resolve Maxwell's Demon paradox, etc. etc.

Saibal

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Re: Born's rule from almost nothing

On Thu, Jan 28, 2021 at 9:51 AM 'Brent Meeker' via Everything List <
everything-list@googlegroups.com> wrote:

> On 1/27/2021 2:28 PM, Bruce Kellett wrote:
>
> On Thu, Jan 28, 2021 at 3:08 AM Bruno Marchal  wrote:
>
>>
>> Also, worlds interfere statistically, by do not interact at all. A term
>> in a superposition cannot interact with any other terms, but we can make
>> them interfering, like with the two slits.
>>
>
>
> Your grasp of the relevant physics is rather tenuous, I'm afraid Bruno.
> The idea of "worlds interfering statistically without interacting" is just
> a nonsense.  There can only be interference if there is an interaction. And
> there certainly is an interaction between the photons on the two possible
> paths in the two slit experiment. The two paths arrive at the screen with
> different amplitudes and phases -- if the signs are the same, they add. But
> if the signs are different they cancel -- partially or completely depending
> on the relative amplitudes.
>
> The trouble is that David Deutsch has really screwed up the understanding
> of "worlds" for a lot of people. He has talked as though each path in the
> two slit case is a separate "world", and then has to resort to magic to
> reproduce the interference. The Everett concept of a "world" is a "relative
> state", in which an "observer" sees a definite result. This idea was made
> more precise with the introduction of the idea of decoherence, and
> generalized entanglement with the environment. If "worlds" are defined as
> the result of decoherent histories, then Deutsch's confusion should not
> arise. A "world" is the result of (FAPP irreversible) decoherence. There is
> no decoherence at the slits in the two slit experiment, so no separate
> "worlds" are formed. If you induce decoherence by measuring at the slits,
> then the interference pattern disappears -- you have certainly created a
> separate "world" for each path, but these can no longer interfere. That is
> part of the definition of the "worlds" that are created by irreversible
> decoherence.
>
>
> That's where I think there is still a gap in the theory.  We know that in
> the C60 double slit experiment the interference is wiped out because
> sufficiently short wavelength IR photons from the buckyballs record their
> position in the environment, presumably when they are absorbed in the
> laboratory walls.  But what would happen if they weren't registered any
> where.  What if the experiment were in outer space and the IR photons just
> went off into infinity in a spherically symmetric wavefunction that never
> "collapsed"?
>


I thought that was answered in one of Zeilinger's delayed choice
experiments.  The idler photons that carry the 'welcher weg' information do
not have to be measured or intercepted. As long as they exist anywhere in
the universe, the interference is destroyed. You have to actually 'quantum
erase' the 'welcher weg' information they carry in order to restore the
interference. Running the idler photons into the wall is not quantum
erasure.

Bruce

So the concept of "world" is, indeed, well-defined in physics. It might not
> be defined in logic or metaphysics, but this is of no concern to the
> working physicist -- we know perfectly well what we mean by "a world". And
> we can readily tell when someone is talking nonsense by claiming that
> "worlds interfere statistically without interacting". The superposition of
> the paths in the two slit case extends right to the screen: that is what
> produces the interference -- superposition means that the two components
> are added together with their intrinsic phases intact. If you destroy the
> superposition at any point, such as by interacting with the paths at the
> slits, there is no more interference -- you have produced separate "worlds"
> that can no longer interact so there is no interference. As Scott Aaronson
> is fond of saying: quantum computers work by interference, so the
> computations must all occur in one "world". As Scott recently posted:
> "BREAKING: President Biden signs executive order banning people from saying
> "Quantum computers solve problems by just trying all possible solutions in
> parallel"."
>
> Bruce
>
>

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Re: Born's rule from almost nothing

2021-01-27 Thread 'Brent Meeker' via Everything List

On 1/27/2021 2:28 PM, Bruce Kellett wrote:
On Thu, Jan 28, 2021 at 3:08 AM Bruno Marchal > wrote:

Also, worlds interfere statistically, by do not interact at all. A
term in a superposition cannot interact with any other terms, but
we can make them interfering, like with the two slits.

The trouble is that David Deutsch has really screwed up the
understanding of "worlds" for a lot of people. He has talked as though
each path in the two slit case is a separate "world", and then has to
resort to magic to reproduce the interference. The Everett concept of
a "world" is a "relative state", in which an "observer" sees a
definite result. This idea was made more precise with the
introduction of the idea of decoherence, and generalized entanglement
with the environment. If "worlds" are defined as the result of
decoherent histories, then Deutsch's confusion should not arise. A
"world" is the result of (FAPP irreversible) decoherence. There is no
decoherence at the slits in the two slit experiment, so no separate
"worlds" are formed. If you induce decoherence by measuring at the
slits, then the interference pattern disappears -- you have
certainly created a separate "world" for each path, but these can no
longer interfere. That is part of the definition of the "worlds" that
are created by irreversible decoherence.

That's where I think there is still a gap in the theory. We know that
in the C60 double slit experiment the interference is wiped out because
sufficiently short wavelength IR photons from the buckyballs record
their position in the environment, presumably when they are absorbed in
the laboratory walls. But what would happen if they weren't registered
any where. What if the experiment were in outer space and the IR
photons just went off into infinity in a spherically symmetric
wavefunction that never "collapsed"?

Brent

Bruce
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Re: Born's rule from almost nothing

On Thu, Jan 28, 2021 at 3:08 AM Bruno Marchal  wrote:

>
> Also, worlds interfere statistically, by do not interact at all. A term in
> a superposition cannot interact with any other terms, but we can make them
> interfering, like with the two slits.
>

Your grasp of the relevant physics is rather tenuous, I'm afraid Bruno. The
idea of "worlds interfering statistically without interacting" is just a
nonsense.  There can only be interference if there is an interaction. And
there certainly is an interaction between the photons on the two possible
paths in the two slit experiment. The two paths arrive at the screen with
different amplitudes and phases -- if the signs are the same, they add. But
if the signs are different they cancel -- partially or completely depending
on the relative amplitudes.

The trouble is that David Deutsch has really screwed up the understanding
of "worlds" for a lot of people. He has talked as though each path in the
two slit case is a separate "world", and then has to resort to magic to
reproduce the interference. The Everett concept of a "world" is a "relative
state", in which an "observer" sees a definite result. This idea was made
more precise with the introduction of the idea of decoherence, and
generalized entanglement with the environment. If "worlds" are defined as
the result of decoherent histories, then Deutsch's confusion should not
arise. A "world" is the result of (FAPP irreversible) decoherence. There is
no decoherence at the slits in the two slit experiment, so no separate
"worlds" are formed. If you induce decoherence by measuring at the slits,
then the interference pattern disappears -- you have certainly created a
separate "world" for each path, but these can no longer interfere. That is
part of the definition of the "worlds" that are created by irreversible
decoherence.

So the concept of "world" is, indeed, well-defined in physics. It might not
be defined in logic or metaphysics, but this is of no concern to the
working physicist -- we know perfectly well what we mean by "a world". And
we can readily tell when someone is talking nonsense by claiming that
"worlds interfere statistically without interacting". The superposition of
the paths in the two slit case extends right to the screen: that is what
produces the interference -- superposition means that the two components
are added together with their intrinsic phases intact. If you destroy the
superposition at any point, such as by interacting with the paths at the
slits, there is no more interference -- you have produced separate "worlds"
that can no longer interact so there is no interference. As Scott Aaronson
is fond of saying: quantum computers work by interference, so the
computations must all occur in one "world". As Scott recently posted:
"BREAKING: President Biden signs executive order banning people from saying
"Quantum computers solve problems by just trying all possible solutions in
parallel"."

Bruce

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Re: What top we assume at the start (Re: Born's rule from almost nothing)

On Thu, Jan 28, 2021 at 2:30 AM Bruno Marchal  wrote:

>
> The term “world” is hard to define. For logician, it usually mean an
> element of some non empty set, for a metaphysician, it means the objet of
> the ontological commitment.
>


The trouble, Bruno, is that your world is too small.

Bruce

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Re: Born's rule from almost nothing


> On 17 Jan 2021, at 15:39, Alan Grayson  wrote:
> 
> One of the postulates of the MWI is that everything that can happen, must 
> happen. I just applied it to a horse race. Are you denying that? AG

It is hard to imagine how you will prepare the superposition of the 9 races. I 
have translated this mentally with some more reasonable quantum superposition. 
It is just a bit naïve to say that all that can happen must happen. Only when 
you have prepare the superposition in advance. What you might do is this: you 
decide to give some efficacious drug to one horse choose among all the horse in 
that completion by using some quantum coins, and that case each horse will have 
the drug in “one” world/history, and you reasoning will go through, but of 
course, you cannot predict which horse will get the drug and win. Each of you 
will believe that it is this or that horse, and decoherence will prevent the 
practical “decoherence”, so that you lost the information “said to leak in the 
environment” (not so in a quantum computer, if we succeed to tackle the 
decoherence, as the theory shows that we can, at least in principle (like with 
anyon in condensed matter, or with topological quantum computer).

Bruno




> 
> On Sunday, January 17, 2021 at 4:53:50 AM UTC-7 Pierz wrote:
> On Sun, 17 Jan 2021 at 10:15 pm, Alan Grayson  > wrote:
> 
> 
> On Saturday, January 16, 2021 at 9:55:50 PM UTC-7 Pierz wrote:
> On Sun, 17 Jan 2021 at 3:10 pm, Alan Grayson > wrote:
> 
> 
> On Saturday, January 16, 2021 at 7:28:14 PM UTC-7 Pierz wrote:
> On Sun, 17 Jan 2021 at 3:49 am, Alan Grayson > wrote:
> What would be the mechanism or process for other worlds to interact with each 
> other, that is to interfere with each other? This is the gorilla in the room 
> that many MWI enthusiasts ignore; awesome speculation with zero grounding in 
> empirical evidence. Something definitely awry with this pov. AG
> 
> I’m not an “enthusiast”. It’s a physical theory not a football team. If 
> anything I dislike the idea of all those alternative variants of me and my 
> life. If MWI is disproved I’ll be perfectly happy.
> 
> It can't be disproved because it makes no verifiable predictions! AG
>  
> It’s just that it unfortunately makes more sense in my assessment than any 
> other alternative, so I entertain it as the most likely explanation for the 
> observed data. To say it has zero grounding in empirical data is simply false 
>  - it’s the theory that simply takes the empirical data to its logical 
> conclusion without adding a collapse postulate. The wave function is the 
> whole thing. Asking what the mechanism is for worlds to interfere with one 
> another is the same as asking what the mechanism is for the Schrödinger wave 
> function to interfere with itself. In the dual slit experiment it’s an 
> observed fact.
> 
> The SE, when solved, give us the WF, which can be decomposed into a 
> superposition of eigenstates in some appropriate vector space. But this 
> superposition is not unique. So in what sense does the SE give us "an 
> observed fact"? In fact, with numerous distinct possible superpositions, the 
> worlds of the MWI seem ill-defined. AG
> 
> I have wondered myself whether basis selection is a problem for MWI. I’m less 
> sure now that it is. Environmental einselection may resolve the basis 
> problem. We set up an experimental apparatus to select some basis, but that’s 
> just a special case of what happens naturally, whereby the characteristics of 
> the environment select the basis. 
>  
> It makes no sense for it to behave that way if we stick to the old view of 
> matter as little hard balls, but there you go. When we talk of “worlds”, it 
> just refers to a ramifying quantum state, and it is in the nature of quantum 
> states to interfere with themselves per the dual slit experiment, even if 
> they become large and complex. Interference ceases when two branches of the 
> universal quantum state diverge far enough that they completely decohere. 
> When you say “what is the mechanism?” that really means “what is the 
> mathematical description?” in physics. Anything else is just imprecise 
> circumlocution like the word “world” in this context. So the mechanism for 
> interference is the Schrödinger equation, which predicts such interference. 
> MWI adds precisely nothing to that mathematical description.
> 
> The problem, of course, is that the MWI offers no concept of the process of 
> interference among OTHER worlds, so it's no surprise that it adds nothing to 
> the mathematical description. AG  (More at end of this confusing file.)
> 
> there you go with “of course” again as if your argument were self evident. 
> Theres no distinction between worlds (this or other) so of course there is 
> interference on and among the other branches too. I don’t know what you’re 
> talking about.
> 
> I strongly disagree. IMO, it is self-evident. My response is at end of this 
> file. AG 
> 
> The ontological status of those OTHER

Re: Born's rule from almost nothing


> On 17 Jan 2021, at 12:15, Alan Grayson  wrote:
> 
> 
> 
> On Saturday, January 16, 2021 at 9:55:50 PM UTC-7 Pierz wrote:
> On Sun, 17 Jan 2021 at 3:10 pm, Alan Grayson  > wrote:
> 
> 
> On Saturday, January 16, 2021 at 7:28:14 PM UTC-7 Pierz wrote:
> On Sun, 17 Jan 2021 at 3:49 am, Alan Grayson > wrote:
> What would be the mechanism or process for other worlds to interact with each 
> other, that is to interfere with each other? This is the gorilla in the room 
> that many MWI enthusiasts ignore; awesome speculation with zero grounding in 
> empirical evidence. Something definitely awry with this pov. AG
> 
> I’m not an “enthusiast”. It’s a physical theory not a football team. If 
> anything I dislike the idea of all those alternative variants of me and my 
> life. If MWI is disproved I’ll be perfectly happy.
> 
> It can't be disproved because it makes no verifiable predictions! AG
>  
> It’s just that it unfortunately makes more sense in my assessment than any 
> other alternative, so I entertain it as the most likely explanation for the 
> observed data. To say it has zero grounding in empirical data is simply false 
>  - it’s the theory that simply takes the empirical data to its logical 
> conclusion without adding a collapse postulate. The wave function is the 
> whole thing. Asking what the mechanism is for worlds to interfere with one 
> another is the same as asking what the mechanism is for the Schrödinger wave 
> function to interfere with itself. In the dual slit experiment it’s an 
> observed fact.
> 
> The SE, when solved, give us the WF, which can be decomposed into a 
> superposition of eigenstates in some appropriate vector space. But this 
> superposition is not unique. So in what sense does the SE give us "an 
> observed fact"? In fact, with numerous distinct possible superpositions, the 
> worlds of the MWI seem ill-defined. AG
> 
> I have wondered myself whether basis selection is a problem for MWI. I’m less 
> sure now that it is. Environmental einselection may resolve the basis 
> problem. We set up an experimental apparatus to select some basis, but that’s 
> just a special case of what happens naturally, whereby the characteristics of 
> the environment select the basis. 
>  
> It makes no sense for it to behave that way if we stick to the old view of 
> matter as little hard balls, but there you go. When we talk of “worlds”, it 
> just refers to a ramifying quantum state, and it is in the nature of quantum 
> states to interfere with themselves per the dual slit experiment, even if 
> they become large and complex. Interference ceases when two branches of the 
> universal quantum state diverge far enough that they completely decohere. 
> When you say “what is the mechanism?” that really means “what is the 
> mathematical description?” in physics. Anything else is just imprecise 
> circumlocution like the word “world” in this context. So the mechanism for 
> interference is the Schrödinger equation, which predicts such interference. 
> MWI adds precisely nothing to that mathematical description.
> 
> The problem, of course, is that the MWI offers no concept of the process of 
> interference among OTHER worlds, so it's no surprise that it adds nothing to 
> the mathematical description. AG  (More at end of this confusing file.)
> 
> there you go with “of course” again as if your argument were self evident. 
> Theres no distinction between worlds (this or other) so of course there is 
> interference on and among the other branches too. I don’t know what you’re 
> talking about.
> 
> I strongly disagree. IMO, it is self-evident. My response is at end of this 
> file. AG 
> 
> The ontological status of those OTHER worlds is problem, but that's not 
> exactly what I am saying. Rather, I am saying is that the MW hypothesis leads 
> nowhere. It has no predictive value that I can discern. It's just a form of 
> possibly consistent ideology. Compare it to Einstein's postulate of the 
> invariance of the SoL. It's really quite paradoxical when you think about; 
> that the SoL does not depend on the motion of source or recipient. But from 
> it we get the LT and a host of verifiable predictions. SR is a scientific 
> theory since it can be disproven. I don't see that anything verifiable is 
> predicted by the MWI. As such, it shouldn't be regarded as a scientific 
> theory. It can't be so considered since it offer no path for being disproven. 
> AG 
> 
> That is not what you said in your initial argument at all.
> 
>  It was about Born's rule failing in the MWI because the OTHER worlds don't 
> interact. AG
>  
> But to run with it, falsifiability is definitely a problem for MWI, but it’s 
> not as straightforward as you make out. There are proposals for falsifying it 
> but they are technically too difficult to carry out at the moment. 
> Falsifiability is not an intrinsic property of a theory but a property of the 
> theory in relation to the current state of knowledge and technology.

Re: Born's rule from almost nothing


> On 17 Jan 2021, at 03:03, Pierz Newton-John  wrote:
> 
> 
> 
> On Sun, 17 Jan 2021 at 3:49 am, Alan Grayson  > wrote:
> What would be the mechanism or process for other worlds to interact with each 
> other, that is to interfere with each other? This is the gorilla in the room 
> that many MWI enthusiasts ignore; awesome speculation with zero grounding in 
> empirical evidence. Something definitely awry with this pov. AG
> 
> I’m not an “enthusiast”. It’s a physical theory not a football team. If 
> anything I dislike the idea of all those alternative variants of me and my 
> life. If MWI is disproved I’ll be perfectly happy. It’s just that it 
> unfortunately makes more sense in my assessment than any other alternative, 
> so I entertain it as the most likely explanation for the observed data. To 
> say it has zero grounding in empirical data is simply false  - it’s the 
> theory that simply takes the empirical data to its logical conclusion without 
> adding a collapse postulate. The wave function is the whole thing. Asking 
> what the mechanism is for worlds to interfere with one another is the same as 
> asking what the mechanism is for the Schrödinger wave function to interfere 
> with itself. In the dual slit experiment it’s an observed fact. It makes no 
> sense for it to behave that way if we stick to the old view of matter as 
> little hard balls, but there you go. When we talk of “worlds”, it just refers 
> to a ramifying quantum state, and it is in the nature of quantum states to 
> interfere with themselves per the dual slit experiment, even if they become 
> large and complex. Interference ceases when two branches of the universal 
> quantum state diverge far enough that they completely decohere. When you say 
> “what is the mechanism?” that really means “what is the mathematical 
> description?” in physics. Anything else is just imprecise circumlocution like 
> the word “world” in this context. So the mechanism for interference is the 
> Schrödinger equation, which predicts such interference. MWI adds precisely 
> nothing to that mathematical description.


Yes. To avoid the MWI, the early founders of QM *added* an axiom: the wave 
collapse postulate. But it introduce a non intelligible dualism with an unknown 
theory of mind. It makes everything more complicated, for reason of 
philosophical taste, which is alway dubious. Occam Razor favour the theory with 
as much axioms as possible.

Especially if one believe in Mechanism. This asks us to believe that 2+2=4 & 
Co., which entails the existence of all computations, with a extraordinary 
complex redundancy of those computations, implying the existence of a (Lebgues) 
Measure on their first person limit (the “observer” cannot be aware of the 
number of steps of the universal dovetailing (which occur in all models of any  
theory of arithmetic). So ...

Bruno


> 
> 
> On Saturday, January 16, 2021 at 9:32:49 AM UTC-7 Alan Grayson wrote:
> On Saturday, January 16, 2021 at 1:23:52 AM UTC-7 Pierz wrote:
> On Sat, 16 Jan 2021 at 2:18 pm, Alan Grayson > wrote:
> 
> 
> On Friday, January 15, 2021 at 6:16:25 PM UTC-7 Pierz wrote:
> On Sat, 16 Jan 2021 at 5:56 am, Alan Grayson > wrote:
> 
> 
> On Thursday, January 14, 2021 at 11:36:39 PM UTC-7 Pierz wrote:
> On Fri, 15 Jan 2021 at 4:01 pm, Alan Grayson > wrote:
> 
> 
> On Thursday, January 14, 2021 at 3:15:47 PM UTC-7, Pierz wrote:
> 
> 
> On Thursday, January 14, 2021 at 11:07:59 PM UTC+11 agrays...@gmail.com <> 
> wrote:
> On Thursday, January 14, 2021 at 2:26:42 AM UTC-7 Pierz wrote:
> On Thursday, January 14, 2021 at 2:42:43 PM UTC+11 agrays...@gmail.com <> 
> wrote:
> On Wednesday, January 13, 2021 at 8:29:16 PM UTC-7 Pierz wrote:
> On Thursday, January 14, 2021 at 1:23:11 PM UTC+11 agrays...@gmail.com <> 
> wrote:
> On Wednesday, January 13, 2021 at 4:33:20 PM UTC-7 Pierz wrote:
> On Wednesday, January 13, 2021 at 5:50:29 PM UTC+11 agrays...@gmail.com <> 
> wrote:
> On Tuesday, January 12, 2021 at 10:19:59 PM UTC-7 Pierz wrote:
> 
> 
> On Monday, January 4, 2021 at 12:09:06 PM UTC+11 agrays...@gmail.com <> wrote:
> On Sunday, January 3, 2021 at 3:56:51 PM UTC-7 johnk...@gmail.com <> wrote:
> On Sun, Jan 3, 2021 at 5:21 PM Alan Grayson > wrote:
> 
> > The MWI doesn't guarantee that these subsequent measurements, for 
> > subsequent horse races say, are occurring in the SAME OTHER worlds as 
> > trials progress, to get ensembles in those OTHER worlds. 
>  
> I don't know what you mean by "SAME OTHER worlds", the same as what? In one 
> world Alan Grayson remembers having seen the electron go left, in another 
> world Alan Grayson remembers having seen the electron go right, other than 
> that the two worlds are absolutely identical, so which one was the "SAME 
> OTHER world"?
> 
> > You seem to avoid the fact that no where does the MWI guarantee [...]
> 
> Quantum mechanics is not in the guarantee business, it deals with 
> probability.  
> 
> > I don't think you

Re: Born's rule from almost nothing


> On 16 Jan 2021, at 17:49, Alan Grayson  wrote:
> 
> What would be the mechanism or process for other worlds to interact with each 
> other, that is to interfere with each other? This is the gorilla in the room 
> that many MWI enthusiasts ignore; awesome speculation with zero grounding in 
> empirical evidence. Something definitely awry with this pov. AG

0 world, 1 world, 2 worlds, … aleph_0 worlds, aleph_1 worlds, etc.. ALL of them 
are as much speculation than any other.

Also, worlds interfere statistically, by do not interact at all. A term in a 
superposition cannot interact with any other terms, but we can make them 
interfering, like with the two slits.

Mechanism makes this simpler: there are 0 world, and there is an apperaance of 
1 world above the substitution level, and of infinity of worlds below the 
substitution level. ((Digital)Mechanism is the assumption that there is a level 
of substitution of you such that you survive a body part substitution made at 
that (digital) level).

Bruno




> 
> On Saturday, January 16, 2021 at 9:32:49 AM UTC-7 Alan Grayson wrote:
> On Saturday, January 16, 2021 at 1:23:52 AM UTC-7 Pierz wrote:
> On Sat, 16 Jan 2021 at 2:18 pm, Alan Grayson > wrote:
> 
> 
> On Friday, January 15, 2021 at 6:16:25 PM UTC-7 Pierz wrote:
> On Sat, 16 Jan 2021 at 5:56 am, Alan Grayson > wrote:
> 
> 
> On Thursday, January 14, 2021 at 11:36:39 PM UTC-7 Pierz wrote:
> On Fri, 15 Jan 2021 at 4:01 pm, Alan Grayson > wrote:
> 
> 
> On Thursday, January 14, 2021 at 3:15:47 PM UTC-7, Pierz wrote:
> 
> 
> On Thursday, January 14, 2021 at 11:07:59 PM UTC+11 agrays...@gmail.com <> 
> wrote:
> On Thursday, January 14, 2021 at 2:26:42 AM UTC-7 Pierz wrote:
> On Thursday, January 14, 2021 at 2:42:43 PM UTC+11 agrays...@gmail.com <> 
> wrote:
> On Wednesday, January 13, 2021 at 8:29:16 PM UTC-7 Pierz wrote:
> On Thursday, January 14, 2021 at 1:23:11 PM UTC+11 agrays...@gmail.com <> 
> wrote:
> On Wednesday, January 13, 2021 at 4:33:20 PM UTC-7 Pierz wrote:
> On Wednesday, January 13, 2021 at 5:50:29 PM UTC+11 agrays...@gmail.com <> 
> wrote:
> On Tuesday, January 12, 2021 at 10:19:59 PM UTC-7 Pierz wrote:
> 
> 
> On Monday, January 4, 2021 at 12:09:06 PM UTC+11 agrays...@gmail.com <> wrote:
> On Sunday, January 3, 2021 at 3:56:51 PM UTC-7 johnk...@gmail.com <> wrote:
> On Sun, Jan 3, 2021 at 5:21 PM Alan Grayson > wrote:
> 
> > The MWI doesn't guarantee that these subsequent measurements, for 
> > subsequent horse races say, are occurring in the SAME OTHER worlds as 
> > trials progress, to get ensembles in those OTHER worlds. 
>  
> I don't know what you mean by "SAME OTHER worlds", the same as what? In one 
> world Alan Grayson remembers having seen the electron go left, in another 
> world Alan Grayson remembers having seen the electron go right, other than 
> that the two worlds are absolutely identical, so which one was the "SAME 
> OTHER world"?
> 
> > You seem to avoid the fact that no where does the MWI guarantee [...]
> 
> Quantum mechanics is not in the guarantee business, it deals with 
> probability.  
> 
> > I don't think you understand my point, which isn't complicated. 
> 
> Yes, your point is very simple indeed, but the word simple can have 2 
> meanings, one of them is complementary and the other not so much.  
> 
> In first trial, the MWI postulates other worlds comes into existence. Same 
> other worlds in second trial? Same other worlds in third trial, etc? Where 
> does the MWI assert these other worlds are the SAME other worlds? Unless it 
> does, you only have ONE measurement in each of these worlds. No probability 
> exists in these other worlds since no ensemble of measurements exist in these 
> other world. AG
>  
> You grossly misunderstand MWI. There are no "same other" worlds. The worlds 
> that arise at each trial are different in precisely one way and one way only: 
> the eigenvalue recorded for the experiment. The different eigenvalues will 
> then give rise to a "wave of differentiations" as the consequences of that 
> singular difference ramifies, causing the different worlds generated by the 
> original experimental difference to multiply. "World" really means a unique 
> configuration of the universal wave function, so two worlds at different 
> trials can't possibly be the "same world", and yes, there is only one 
> measurement in each.
> 
> This is what I have been saying all along! AG
> No it isn't. I agree you have been saying there is only one measurement 
> outcome in each world. However this business about "same other worlds" 
> betrays your lack of comprehension. It's not that MWI "doesn't guarantee" 
> that the the worlds at each trial are the same world. It's that the whole 
> notion of "same other worlds" means nothing in this context and has no 
> bearing on anything. A bit like arguing when we add 1 and 1 twice whether we 
> are guaranteed that the ones we add each time are the "SAME ones" at each 
> addition. If mathematics can't guarantee

Re: Born's rule from almost nothing


> On 16 Jan 2021, at 10:37, 'scerir' via Everything List 
>  wrote:
> 
> "They show that MWI is inconsistent, in the Schroedinger picture. 
> https://link.springer.com/article/10.1007%2FBF00763476;
> 
> the paper (pdf) is here: 
> 
> http://www.socsci.uci.edu/~jabarret/bio/publications/ToBeAWorld.pdf
> 
Thanks. It is indeed interesting. It still lacks some attempt to be precise on 
the notion of world that they debunk, and it could say more on a comparison 
with the notion of histories of Griffith and Omnès. I might say more later.

Bruno 



> 
> 
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Re: Born's rule from almost nothing


> On 16 Jan 2021, at 10:15, 'scerir' via Everything List 
>  wrote:
> 
> Pierz wrote: "If you want to argue against the internal logic of MWI, you 
> have to start by accepting what it proposes then proceeding to demonstrate 
> how that leads to internal inconsistency."
> 
> They show that MWI is inconsistent, in the Schroedinger picture. 
> https://link.springer.com/article/10.1007%2FBF00763476
> 
> 


That papers seem interesting, and might be related to what I just say to 
Grayson, as it cites Hartle-Gell’man, but also Omnes, which in my opinion 
refine rather well the notion of “worlds” through the notion of (consistent) 
histories (unfortunately the term “consistent” here has not the same meaning 
than the term consistent in logic, but mechanism relates them in some way.

Bruno



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Re: Born's rule from almost nothing

Le mer. 27 janv. 2021 à 16:04, Alan Grayson  a
écrit :

>
>
> On Wednesday, January 27, 2021 at 6:26:50 AM UTC-7 Quentin Anciaux wrote:
>
>> Le mer. 27 janv. 2021 à 13:38, Alan Grayson  a
>> écrit :
>>
>>>
>>>
>>> On Wednesday, January 27, 2021 at 5:14:33 AM UTC-7 Quentin Anciaux wrote:
>>>


 Le mer. 27 janv. 2021 à 12:19, Alan Grayson  a
 écrit :

>
>
> On Wednesday, January 27, 2021 at 3:56:50 AM UTC-7 Quentin Anciaux
> wrote:
>
>>
>>
>> Le mer. 27 janv. 2021 à 11:54, Alan Grayson  a
>> écrit :
>>
>>>
>>>
>>> On Tuesday, January 12, 2021 at 10:19:59 PM UTC-7 Pierz wrote:
>>>


 On Monday, January 4, 2021 at 12:09:06 PM UTC+11
 agrays...@gmail.com wrote:

> On Sunday, January 3, 2021 at 3:56:51 PM UTC-7 johnk...@gmail.com
> wrote:
>
>> On Sun, Jan 3, 2021 at 5:21 PM Alan Grayson 
>> wrote:
>>
>> *> The MWI doesn't guarantee that these subsequent measurements,
>>> for subsequent horse races say, are occurring in the SAME OTHER 
>>> worlds as
>>> trials progress, to get ensembles in those OTHER worlds. *
>>
>>
>> I don't know what you mean by "SAME OTHER worlds", the same as
>> what? In one world Alan Grayson remembers having seen the electron 
>> go left,
>> in another world Alan Grayson remembers having seen the electron go 
>> right,
>> other than that the two worlds are absolutely identical, so which 
>> one was
>> the "SAME OTHER world"?
>>
>> > You seem to avoid the fact that no where does the MWI guarantee
>>> [...]
>>
>>
>> Quantum mechanics is not in the guarantee business, it deals with
>> probability.
>>
>> *> I don't think you understand my point, which isn't
>>> complicated. *
>>
>>
>> Yes, your point is very simple indeed, but the word simple can
>> have 2 meanings, one of them is complementary and the other not
>> so much.
>>
>
> In first trial, the MWI postulates other worlds comes into
> existence. Same other worlds in second trial? Same other worlds in 
> third
> trial, etc? Where does the MWI assert these other worlds are the SAME 
> other
> worlds? Unless it does, you only have ONE measurement in each of these
> worlds. No probability exists in these other worlds since no ensemble 
> of
> measurements exist in these other world. AG
>

 You grossly misunderstand MWI. There are no "same other" worlds.
 The worlds that arise at each trial are different in precisely one way 
 and
 one way only: the eigenvalue recorded for the experiment. The different
 eigenvalues will then give rise to a "wave of differentiations" as the
 consequences of that singular difference ramifies, causing the 
 different
 worlds generated by the original experimental difference to multiply.
 "World" really means a unique configuration of the universal wave 
 function,
 so two worlds at different trials can't possibly be the "same world", 
 and
 yes, there is only one measurement in each.

>>>
>>> *If there is only one measurement in each other world -- which has
>>> been my claim throughout -- how can Born's rule be satisfied in the 
>>> MWI? AG*
>>>
>>
>> Every world has a past... So if you do n experiments after n trials
>> you have 2^n number of worlds each having a past of n trials.
>>
>
> *On the second trial and another splitting, what is the assurance that
> the new other world is the same as that created on the first splitting, so
> a sequence of measurement history exists? AG*
>

>>>
 It has the same past, if you say you'll do 9 trials in advance, then
 most "worlds" after your 9 trials will have done 9 trials(without
 considering ultra low probability worlds) and all nine worlds will share
 the same past before any trials.

>>>
>>> *So the assurance I seek is simply your claim that it is so? AG *
>>>
>>
>> No that's what MWI claims... if you claim otherwise... well simply that's
>> not MWI... but your own theory... that you can't use to say anything about
>> MWI because your theory is not MWI.
>>
>
> *I am asking how you get that claim from the SWE, if it's not an
> independent postulate. AG *
>

That all results are realized... so at every trials all possible results
results.. and each worlds "split/differentiate" at each moments and
each worlds has a past.

So starting at time t... at t1 you have all possible split having t has
ancestor... etc... no independent postulate needed... but your theory that
a world exists

What top we assume at the start (Re: Born's rule from almost nothing)

> On 27 Jan 2021, at 08:36, Alan Grayson  wrote:
> 
> 
> 
> On Tuesday, January 26, 2021 at 9:27:43 AM UTC-7 Bruno Marchal wrote:
> 
>> On 15 Jan 2021, at 23:34, Alan Grayson > > wrote:
>> 
>> Why not assume the wf applies only before the measurement?
> 
> That’s Bohr idea. But it means that measurement are no more describe by QM, 
> and this introduces a dualism in the the possible theory of mind that you 
> need to use. The élégance if the MWI is that QM applies to both the observed 
> and the observer, again, like it has to do assuming mechanism.
> 
> 
> 
>> Or why not withhold judgement on a phenomenon not yet understood? Instead 
>> you totally dismiss empirical evidence that no one ever observes a split. AG
> 
> We still observe the result predicted when accepting the superposed wave 
> going through all slit. The fact that we don’t feel the split is entirely 
> explained by the wave evolution and the self-duplication thought experiment. 
> Occam razor favours the simplest conceptual explanation, or we add add as 
> many “epicycle” to favour any interpretation, up to the super determinism, 
> which I take as an abandon of rationality…
> 
> Bruno
> 
> Yeah, "entirely explained", except for the huge gorilla in the room. Where's 
> the beef, I mean the energy to create those other worlds? Is it in the 
> non-computable irrational numbers?  AG

The term “world” is hard to define. For logician, it usually mean an element of 
some non empty set, for a metaphysician, it means the objet of the ontological 
commitment.

The problem here is that some metaphysical assumption are done implicitly. I 
prefer to avoid any ontological commitment bigger than what we need when we do 
metaphysics, and with Mechanism, I can explain that we need only a universal 
machinery (in the sense of the logicians, Turing, Kleene). It happens that for 
the ontology, the very elementary arithmetic is enough. It is given by the 
usual classical predicate calculus and the axioms:

1) 0 ≠ s(x)
2) x ≠ y -> s(x) ≠ s(y)
3) x ≠ 0 -> Ey(x = s(y)) 
4) x+0 = x
5) x+s(y) = s(x+y)
6) x*0=0
7) x*s(y)=(x*y)+x

Then an observer is defined by any machine/number having those axioms as 
belief, together with the scheme of axioms of induction, the set of 
rationally-believable proposition of the agent contains all formula, with A an 
arbitrary arithmetical formula:

[A(0) & for all n (A(n) -> (A(s(n)) ] -> for all n A(n)

Note that the observer has many more axioms than what we need for the ontology.

In the ontological theory, we can define what is a universal machine, and what 
is a computation. The Digital Mechanist hypothesis entails that the ontology is 
enough to get *all* computations, and it makes the machine non determined with 
respect to which computations support it. But the machine can do reasoning, and 
indeed the observer can prove that if mechanism is correct, the observable 
(“physics”) can arise only from a statistic on all computations, and the math 
indicates already that this will obey a quantum logic quite close to the 
quantum logic based on the Hartle-Graham, or Griffith-Omnes (see also Isham) 
logic of alternate (but first person fungible) histories.

It is up to a materialist (or a believer in some god) to explain how matter (or 
god) can select histories in the set of all histories.
An history here is defined by a computation as seen by some observer (as 
defined above, with observable being defined by an intensional (modal variant 
of the Gödel-Löb-Solovay logic G* (in the study of arithmetical self-reference).

We cannot use the usual brain-mind identity principle (it is false with 
Mechanism, and unclear in most interpretation of QM). We can attach some person 
to a machine, but no person can attach his own mind to a “particular machine”, 
only to all digital machines occurring in arithmetic and getting the state of 
that observer (there are infinitely many).

The “beef” is what I want to explain, and the result is that there is no beef, 
only sets of “dreams of beef”, and the math explain why such set get structured 
into physical persistent observable. 

Einstein said that time is an illusion, albeit a persistent one! Mechanism go 
farer, and explains that the whole physicalness is an illusion by number, and 
explain its persistence and its apparent localisation as part of the machine 
reference and self-reference relatively to infinitely many universal numbers.

The advantage of this approach is twofold: 
1) it does not rely on an ontological commitment different than the term we 
need to define a machine (of course, we have to still postulate elementary 
arithmetic (this can be explained not deducible from less or equivalent).
2) we get a natural explanation of the difference between quanta and qualia. 
Both are measurable numbers, but only the quanta are first person plural 
sharable. The qualia are irreducibly NON sharable, and not perceivable as 
numbers, but as different sort of sensations.

It is hard for me

Re: Born's rule from almost nothing



On Wednesday, January 27, 2021 at 6:26:50 AM UTC-7 Quentin Anciaux wrote:

> Le mer. 27 janv. 2021 à 13:38, Alan Grayson  a 
> écrit :
>
>>
>>
>> On Wednesday, January 27, 2021 at 5:14:33 AM UTC-7 Quentin Anciaux wrote:
>>
>>>
>>>
>>> Le mer. 27 janv. 2021 à 12:19, Alan Grayson  a 
>>> écrit :
>>>


 On Wednesday, January 27, 2021 at 3:56:50 AM UTC-7 Quentin Anciaux 
 wrote:

>
>
> Le mer. 27 janv. 2021 à 11:54, Alan Grayson  a 
> écrit :
>
>>
>>
>> On Tuesday, January 12, 2021 at 10:19:59 PM UTC-7 Pierz wrote:
>>
>>>
>>>
>>> On Monday, January 4, 2021 at 12:09:06 PM UTC+11 agrays...@gmail.com 
>>> wrote:
>>>
 On Sunday, January 3, 2021 at 3:56:51 PM UTC-7 johnk...@gmail.com 
 wrote:

> On Sun, Jan 3, 2021 at 5:21 PM Alan Grayson  
> wrote:
>
> *> The MWI doesn't guarantee that these subsequent measurements, 
>> for subsequent horse races say, are occurring in the SAME OTHER 
>> worlds as 
>> trials progress, to get ensembles in those OTHER worlds. *
>
>  
> I don't know what you mean by "SAME OTHER worlds", the same as 
> what? In one world Alan Grayson remembers having seen the electron go 
> left, 
> in another world Alan Grayson remembers having seen the electron go 
> right, 
> other than that the two worlds are absolutely identical, so which one 
> was 
> the "SAME OTHER world"?
>
> > You seem to avoid the fact that no where does the MWI guarantee 
>> [...]
>
>
> Quantum mechanics is not in the guarantee business, it deals with 
> probability.  
>
> *> I don't think you understand my point, which isn't 
>> complicated. *
>
>
> Yes, your point is very simple indeed, but the word simple can 
> have 2 meanings, one of them is complementary and the other not 
> so much.  
>

 In first trial, the MWI postulates other worlds comes into 
 existence. Same other worlds in second trial? Same other worlds in 
 third 
 trial, etc? Where does the MWI assert these other worlds are the SAME 
 other 
 worlds? Unless it does, you only have ONE measurement in each of these 
 worlds. No probability exists in these other worlds since no ensemble 
 of 
 measurements exist in these other world. AG

>>>  
>>> You grossly misunderstand MWI. There are no "same other" worlds. The 
>>> worlds that arise at each trial are different in precisely one way and 
>>> one 
>>> way only: the eigenvalue recorded for the experiment. The different 
>>> eigenvalues will then give rise to a "wave of differentiations" as the 
>>> consequences of that singular difference ramifies, causing the 
>>> different 
>>> worlds generated by the original experimental difference to multiply. 
>>> "World" really means a unique configuration of the universal wave 
>>> function, 
>>> so two worlds at different trials can't possibly be the "same world", 
>>> and 
>>> yes, there is only one measurement in each. 
>>>
>>  
>> *If there is only one measurement in each other world -- which has 
>> been my claim throughout -- how can Born's rule be satisfied in the MWI? 
>> AG*
>>
>
> Every world has a past... So if you do n experiments after n trials 
> you have 2^n number of worlds each having a past of n trials.
>

 *On the second trial and another splitting, what is the assurance that 
 the new other world is the same as that created on the first splitting, so 
 a sequence of measurement history exists? AG*

>>>  
>>
>>> It has the same past, if you say you'll do 9 trials in advance, then 
>>> most "worlds" after your 9 trials will have done 9 trials(without 
>>> considering ultra low probability worlds) and all nine worlds will share 
>>> the same past before any trials.
>>>
>>
>> *So the assurance I seek is simply your claim that it is so? AG *
>>
>
> No that's what MWI claims... if you claim otherwise... well simply that's 
> not MWI... but your own theory... that you can't use to say anything about 
> MWI because your theory is not MWI. 
>

*I am asking how you get that claim from the SWE, if it's not an 
independent postulate. AG *

>

>>
>>  
>>
>>> That is precisely the stipulation of MWI. If we have a quantum 
>>> experiment with two eigenvalues 1 and 0, and each is equally likely per 
>>> the 
>>> Born rule, then the MWI interpretation is that - effectively - two 
>>> worlds 
>>> are created. You, the experimenter, end up in both, each version 
>>> knowing 
>>> nothing about the other. So, in the "objective world" (the view from 
>>>

Re: Born's rule from almost nothing

Le mer. 27 janv. 2021 à 13:38, Alan Grayson  a
écrit :

>
>
> On Wednesday, January 27, 2021 at 5:14:33 AM UTC-7 Quentin Anciaux wrote:
>
>>
>>
>> Le mer. 27 janv. 2021 à 12:19, Alan Grayson  a
>> écrit :
>>
>>>
>>>
>>> On Wednesday, January 27, 2021 at 3:56:50 AM UTC-7 Quentin Anciaux wrote:
>>>


 Le mer. 27 janv. 2021 à 11:54, Alan Grayson  a
 écrit :

>
>
> On Tuesday, January 12, 2021 at 10:19:59 PM UTC-7 Pierz wrote:
>
>>
>>
>> On Monday, January 4, 2021 at 12:09:06 PM UTC+11 agrays...@gmail.com
>> wrote:
>>
>>> On Sunday, January 3, 2021 at 3:56:51 PM UTC-7 johnk...@gmail.com
>>> wrote:
>>>
 On Sun, Jan 3, 2021 at 5:21 PM Alan Grayson 
 wrote:

 *> The MWI doesn't guarantee that these subsequent measurements,
> for subsequent horse races say, are occurring in the SAME OTHER 
> worlds as
> trials progress, to get ensembles in those OTHER worlds. *


 I don't know what you mean by "SAME OTHER worlds", the same as
 what? In one world Alan Grayson remembers having seen the electron go 
 left,
 in another world Alan Grayson remembers having seen the electron go 
 right,
 other than that the two worlds are absolutely identical, so which one 
 was
 the "SAME OTHER world"?

 > You seem to avoid the fact that no where does the MWI guarantee
> [...]


 Quantum mechanics is not in the guarantee business, it deals with
 probability.

 *> I don't think you understand my point, which isn't complicated. *


 Yes, your point is very simple indeed, but the word simple can
 have 2 meanings, one of them is complementary and the other not so
 much.

>>>
>>> In first trial, the MWI postulates other worlds comes into
>>> existence. Same other worlds in second trial? Same other worlds in third
>>> trial, etc? Where does the MWI assert these other worlds are the SAME 
>>> other
>>> worlds? Unless it does, you only have ONE measurement in each of these
>>> worlds. No probability exists in these other worlds since no ensemble of
>>> measurements exist in these other world. AG
>>>
>>
>> You grossly misunderstand MWI. There are no "same other" worlds. The
>> worlds that arise at each trial are different in precisely one way and 
>> one
>> way only: the eigenvalue recorded for the experiment. The different
>> eigenvalues will then give rise to a "wave of differentiations" as the
>> consequences of that singular difference ramifies, causing the different
>> worlds generated by the original experimental difference to multiply.
>> "World" really means a unique configuration of the universal wave 
>> function,
>> so two worlds at different trials can't possibly be the "same world", and
>> yes, there is only one measurement in each.
>>
>
> *If there is only one measurement in each other world -- which has
> been my claim throughout -- how can Born's rule be satisfied in the MWI? 
> AG*
>

 Every world has a past... So if you do n experiments after n trials you
 have 2^n number of worlds each having a past of n trials.

>>>
>>> *On the second trial and another splitting, what is the assurance that
>>> the new other world is the same as that created on the first splitting, so
>>> a sequence of measurement history exists? AG*
>>>
>>
>
>> It has the same past, if you say you'll do 9 trials in advance, then most
>> "worlds" after your 9 trials will have done 9 trials(without considering
>> ultra low probability worlds) and all nine worlds will share the same past
>> before any trials.
>>
>
> *So the assurance I seek is simply your claim that it is so? AG *
>

No that's what MWI claims... if you claim otherwise... well simply that's
not MWI... but your own theory... that you can't use to say anything about
MWI because your theory is not MWI.

>
>>>
>
>
>
>> That is precisely the stipulation of MWI. If we have a quantum
>> experiment with two eigenvalues 1 and 0, and each is equally likely per 
>> the
>> Born rule, then the MWI interpretation is that - effectively - two worlds
>> are created. You, the experimenter, end up in both, each version knowing
>> nothing about the other. So, in the "objective world" (the view from
>> outside the whole wave function as it were), no probability is involved.
>> But if you repeat this experiment many times, each version of you will
>> record an apparently random sequence of 1s and 0s. Your best prediction 
>> of
>> what happens in the next experiment is that it's a 50/50 toss up between 
>> 1
>> and 0. Objectively there's no randomness, subjectively it appears that 
>> way.
>>
>>
>>>

Re: Born's rule from almost nothing



On Wednesday, January 27, 2021 at 5:14:33 AM UTC-7 Quentin Anciaux wrote:

>
>
> Le mer. 27 janv. 2021 à 12:19, Alan Grayson  a 
> écrit :
>
>>
>>
>> On Wednesday, January 27, 2021 at 3:56:50 AM UTC-7 Quentin Anciaux wrote:
>>
>>>
>>>
>>> Le mer. 27 janv. 2021 à 11:54, Alan Grayson  a 
>>> écrit :
>>>


 On Tuesday, January 12, 2021 at 10:19:59 PM UTC-7 Pierz wrote:

>
>
> On Monday, January 4, 2021 at 12:09:06 PM UTC+11 agrays...@gmail.com 
> wrote:
>
>> On Sunday, January 3, 2021 at 3:56:51 PM UTC-7 johnk...@gmail.com 
>> wrote:
>>
>>> On Sun, Jan 3, 2021 at 5:21 PM Alan Grayson  
>>> wrote:
>>>
>>> *> The MWI doesn't guarantee that these subsequent measurements, for 
 subsequent horse races say, are occurring in the SAME OTHER worlds as 
 trials progress, to get ensembles in those OTHER worlds. *
>>>
>>>  
>>> I don't know what you mean by "SAME OTHER worlds", the same as what? 
>>> In one world Alan Grayson remembers having seen the electron go left, 
>>> in 
>>> another world Alan Grayson remembers having seen the electron go right, 
>>> other than that the two worlds are absolutely identical, so which one 
>>> was 
>>> the "SAME OTHER world"?
>>>
>>> > You seem to avoid the fact that no where does the MWI guarantee 
 [...]
>>>
>>>
>>> Quantum mechanics is not in the guarantee business, it deals with 
>>> probability.  
>>>
>>> *> I don't think you understand my point, which isn't complicated. *
>>>
>>>
>>> Yes, your point is very simple indeed, but the word simple can have 
>>> 2 meanings, one of them is complementary and the other not so much. 
>>>  
>>>
>>
>> In first trial, the MWI postulates other worlds comes into existence. 
>> Same other worlds in second trial? Same other worlds in third trial, 
>> etc? 
>> Where does the MWI assert these other worlds are the SAME other worlds? 
>> Unless it does, you only have ONE measurement in each of these worlds. 
>> No 
>> probability exists in these other worlds since no ensemble of 
>> measurements 
>> exist in these other world. AG
>>
>  
> You grossly misunderstand MWI. There are no "same other" worlds. The 
> worlds that arise at each trial are different in precisely one way and 
> one 
> way only: the eigenvalue recorded for the experiment. The different 
> eigenvalues will then give rise to a "wave of differentiations" as the 
> consequences of that singular difference ramifies, causing the different 
> worlds generated by the original experimental difference to multiply. 
> "World" really means a unique configuration of the universal wave 
> function, 
> so two worlds at different trials can't possibly be the "same world", and 
> yes, there is only one measurement in each. 
>
  
 *If there is only one measurement in each other world -- which has been 
 my claim throughout -- how can Born's rule be satisfied in the MWI? AG*

>>>
>>> Every world has a past... So if you do n experiments after n trials you 
>>> have 2^n number of worlds each having a past of n trials.
>>>
>>
>> *On the second trial and another splitting, what is the assurance that 
>> the new other world is the same as that created on the first splitting, so 
>> a sequence of measurement history exists? AG*
>>
>  

> It has the same past, if you say you'll do 9 trials in advance, then most 
> "worlds" after your 9 trials will have done 9 trials(without considering 
> ultra low probability worlds) and all nine worlds will share the same past 
> before any trials.
>

*So the assurance I seek is simply your claim that it is so? AG *

>
>>

  

> That is precisely the stipulation of MWI. If we have a quantum 
> experiment with two eigenvalues 1 and 0, and each is equally likely per 
> the 
> Born rule, then the MWI interpretation is that - effectively - two worlds 
> are created. You, the experimenter, end up in both, each version knowing 
> nothing about the other. So, in the "objective world" (the view from 
> outside the whole wave function as it were), no probability is involved. 
> But if you repeat this experiment many times, each version of you will 
> record an apparently random sequence of 1s and 0s. Your best prediction 
> of 
> what happens in the next experiment is that it's a 50/50 toss up between 
> 1 
> and 0. Objectively there's no randomness, subjectively it appears that 
> way.
>  
>
>>  
>>
>>> John K Clark   See my new list at  Extropolis 
>>> 
>>>
>> -- 

>>> 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

Re: Born's rule from almost nothing

Le mer. 27 janv. 2021 à 12:19, Alan Grayson  a
écrit :

>
>
> On Wednesday, January 27, 2021 at 3:56:50 AM UTC-7 Quentin Anciaux wrote:
>
>>
>>
>> Le mer. 27 janv. 2021 à 11:54, Alan Grayson  a
>> écrit :
>>
>>>
>>>
>>> On Tuesday, January 12, 2021 at 10:19:59 PM UTC-7 Pierz wrote:
>>>


 On Monday, January 4, 2021 at 12:09:06 PM UTC+11 agrays...@gmail.com
 wrote:

> On Sunday, January 3, 2021 at 3:56:51 PM UTC-7 johnk...@gmail.com
> wrote:
>
>> On Sun, Jan 3, 2021 at 5:21 PM Alan Grayson 
>> wrote:
>>
>> *> The MWI doesn't guarantee that these subsequent measurements, for
>>> subsequent horse races say, are occurring in the SAME OTHER worlds as
>>> trials progress, to get ensembles in those OTHER worlds. *
>>
>>
>> I don't know what you mean by "SAME OTHER worlds", the same as what?
>> In one world Alan Grayson remembers having seen the electron go left, in
>> another world Alan Grayson remembers having seen the electron go right,
>> other than that the two worlds are absolutely identical, so which one was
>> the "SAME OTHER world"?
>>
>> > You seem to avoid the fact that no where does the MWI guarantee
>>> [...]
>>
>>
>> Quantum mechanics is not in the guarantee business, it deals with
>> probability.
>>
>> *> I don't think you understand my point, which isn't complicated. *
>>
>>
>> Yes, your point is very simple indeed, but the word simple can have 2
>>  meanings, one of them is complementary and the other not so much.
>>
>
> In first trial, the MWI postulates other worlds comes into existence.
> Same other worlds in second trial? Same other worlds in third trial, etc?
> Where does the MWI assert these other worlds are the SAME other worlds?
> Unless it does, you only have ONE measurement in each of these worlds. No
> probability exists in these other worlds since no ensemble of measurements
> exist in these other world. AG
>

 You grossly misunderstand MWI. There are no "same other" worlds. The
 worlds that arise at each trial are different in precisely one way and one
 way only: the eigenvalue recorded for the experiment. The different
 eigenvalues will then give rise to a "wave of differentiations" as the
 consequences of that singular difference ramifies, causing the different
 worlds generated by the original experimental difference to multiply.
 "World" really means a unique configuration of the universal wave function,
 so two worlds at different trials can't possibly be the "same world", and
 yes, there is only one measurement in each.

>>>
>>> *If there is only one measurement in each other world -- which has been
>>> my claim throughout -- how can Born's rule be satisfied in the MWI? AG*
>>>
>>
>> Every world has a past... So if you do n experiments after n trials you
>> have 2^n number of worlds each having a past of n trials.
>>
>
> *On the second trial and another splitting, what is the assurance that the
> new other world is the same as that created on the first splitting, so a
> sequence of measurement history exists? AG*
>
It has the same past, if you say you'll do 9 trials in advance, then most
"worlds" after your 9 trials will have done 9 trials(without considering
ultra low probability worlds) and all nine worlds will share the same past
before any trials.

>
>
>>>
>>>
>>>
 That is precisely the stipulation of MWI. If we have a quantum
 experiment with two eigenvalues 1 and 0, and each is equally likely per the
 Born rule, then the MWI interpretation is that - effectively - two worlds
 are created. You, the experimenter, end up in both, each version knowing
 nothing about the other. So, in the "objective world" (the view from
 outside the whole wave function as it were), no probability is involved.
 But if you repeat this experiment many times, each version of you will
 record an apparently random sequence of 1s and 0s. Your best prediction of
 what happens in the next experiment is that it's a 50/50 toss up between 1
 and 0. Objectively there's no randomness, subjectively it appears that way.


>
>
>> John K Clark   See my new list at  Extropolis
>> 
>>
> --
>>>
>> 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 everything-li...@googlegroups.com.
>>>
>> To view this discussion on the web visit
>>> https://groups.google.com/d/msgid/everything-list/d71dbf38-5943-4f9f-9f1a-f7c5ea822c4cn%40googlegroups.com
>>> 
>>> .
>>>
>> --
> You received this message because you are subscribed to

Re: Born's rule from almost nothing



On Wednesday, January 27, 2021 at 3:56:50 AM UTC-7 Quentin Anciaux wrote:

>
>
> Le mer. 27 janv. 2021 à 11:54, Alan Grayson  a 
> écrit :
>
>>
>>
>> On Tuesday, January 12, 2021 at 10:19:59 PM UTC-7 Pierz wrote:
>>
>>>
>>>
>>> On Monday, January 4, 2021 at 12:09:06 PM UTC+11 agrays...@gmail.com 
>>> wrote:
>>>
 On Sunday, January 3, 2021 at 3:56:51 PM UTC-7 johnk...@gmail.com 
 wrote:

> On Sun, Jan 3, 2021 at 5:21 PM Alan Grayson  
> wrote:
>
> *> The MWI doesn't guarantee that these subsequent measurements, for 
>> subsequent horse races say, are occurring in the SAME OTHER worlds as 
>> trials progress, to get ensembles in those OTHER worlds. *
>
>  
> I don't know what you mean by "SAME OTHER worlds", the same as what? 
> In one world Alan Grayson remembers having seen the electron go left, in 
> another world Alan Grayson remembers having seen the electron go right, 
> other than that the two worlds are absolutely identical, so which one was 
> the "SAME OTHER world"?
>
> > You seem to avoid the fact that no where does the MWI guarantee 
>> [...]
>
>
> Quantum mechanics is not in the guarantee business, it deals with 
> probability.  
>
> *> I don't think you understand my point, which isn't complicated. *
>
>
> Yes, your point is very simple indeed, but the word simple can have 2
>  meanings, one of them is complementary and the other not so much.  
>

 In first trial, the MWI postulates other worlds comes into existence. 
 Same other worlds in second trial? Same other worlds in third trial, etc? 
 Where does the MWI assert these other worlds are the SAME other worlds? 
 Unless it does, you only have ONE measurement in each of these worlds. No 
 probability exists in these other worlds since no ensemble of measurements 
 exist in these other world. AG

>>>  
>>> You grossly misunderstand MWI. There are no "same other" worlds. The 
>>> worlds that arise at each trial are different in precisely one way and one 
>>> way only: the eigenvalue recorded for the experiment. The different 
>>> eigenvalues will then give rise to a "wave of differentiations" as the 
>>> consequences of that singular difference ramifies, causing the different 
>>> worlds generated by the original experimental difference to multiply. 
>>> "World" really means a unique configuration of the universal wave function, 
>>> so two worlds at different trials can't possibly be the "same world", and 
>>> yes, there is only one measurement in each. 
>>>
>>  
>> *If there is only one measurement in each other world -- which has been 
>> my claim throughout -- how can Born's rule be satisfied in the MWI? AG*
>>
>
> Every world has a past... So if you do n experiments after n trials you 
> have 2^n number of worlds each having a past of n trials.
>

*On the second trial and another splitting, what is the assurance that the 
new other world is the same as that created on the first splitting, so a 
sequence of measurement history exists? AG*

>
>>
>>  
>>
>>> That is precisely the stipulation of MWI. If we have a quantum 
>>> experiment with two eigenvalues 1 and 0, and each is equally likely per the 
>>> Born rule, then the MWI interpretation is that - effectively - two worlds 
>>> are created. You, the experimenter, end up in both, each version knowing 
>>> nothing about the other. So, in the "objective world" (the view from 
>>> outside the whole wave function as it were), no probability is involved. 
>>> But if you repeat this experiment many times, each version of you will 
>>> record an apparently random sequence of 1s and 0s. Your best prediction of 
>>> what happens in the next experiment is that it's a 50/50 toss up between 1 
>>> and 0. Objectively there's no randomness, subjectively it appears that way.
>>>  
>>>
  

> John K Clark   See my new list at  Extropolis 
> 
>
 -- 
>>
> 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 everything-li...@googlegroups.com.
>>
> To view this discussion on the web visit 
>> https://groups.google.com/d/msgid/everything-list/d71dbf38-5943-4f9f-9f1a-f7c5ea822c4cn%40googlegroups.com
>>  
>> 
>> .
>>
>

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Re: Born's rule from almost nothing

Le mer. 27 janv. 2021 à 11:54, Alan Grayson  a
écrit :

>
>
> On Tuesday, January 12, 2021 at 10:19:59 PM UTC-7 Pierz wrote:
>
>>
>>
>> On Monday, January 4, 2021 at 12:09:06 PM UTC+11 agrays...@gmail.com
>> wrote:
>>
>>> On Sunday, January 3, 2021 at 3:56:51 PM UTC-7 johnk...@gmail.com wrote:
>>>
 On Sun, Jan 3, 2021 at 5:21 PM Alan Grayson 
 wrote:

 *> The MWI doesn't guarantee that these subsequent measurements, for
> subsequent horse races say, are occurring in the SAME OTHER worlds as
> trials progress, to get ensembles in those OTHER worlds. *


 I don't know what you mean by "SAME OTHER worlds", the same as what? In
 one world Alan Grayson remembers having seen the electron go left, in
 another world Alan Grayson remembers having seen the electron go right,
 other than that the two worlds are absolutely identical, so which one was
 the "SAME OTHER world"?

 > You seem to avoid the fact that no where does the MWI guarantee [...]


 Quantum mechanics is not in the guarantee business, it deals with
 probability.

 *> I don't think you understand my point, which isn't complicated. *


 Yes, your point is very simple indeed, but the word simple can have 2
  meanings, one of them is complementary and the other not so much.

>>>
>>> In first trial, the MWI postulates other worlds comes into existence.
>>> Same other worlds in second trial? Same other worlds in third trial, etc?
>>> Where does the MWI assert these other worlds are the SAME other worlds?
>>> Unless it does, you only have ONE measurement in each of these worlds. No
>>> probability exists in these other worlds since no ensemble of measurements
>>> exist in these other world. AG
>>>
>>
>> You grossly misunderstand MWI. There are no "same other" worlds. The
>> worlds that arise at each trial are different in precisely one way and one
>> way only: the eigenvalue recorded for the experiment. The different
>> eigenvalues will then give rise to a "wave of differentiations" as the
>> consequences of that singular difference ramifies, causing the different
>> worlds generated by the original experimental difference to multiply.
>> "World" really means a unique configuration of the universal wave function,
>> so two worlds at different trials can't possibly be the "same world", and
>> yes, there is only one measurement in each.
>>
>
> *If there is only one measurement in each other world -- which has been my
> claim throughout -- how can Born's rule be satisfied in the MWI*
>
AG*G*
>

Every world has a past... So if you do n experiments after n trials you
have 2^n number of worlds each having a past of n trials.

>
>
>
>
>> That is precisely the stipulation of MWI. If we have a quantum experiment
>> with two eigenvalues 1 and 0, and each is equally likely per the Born rule,
>> then the MWI interpretation is that - effectively - two worlds are created.
>> You, the experimenter, end up in both, each version knowing nothing about
>> the other. So, in the "objective world" (the view from outside the whole
>> wave function as it were), no probability is involved. But if you repeat
>> this experiment many times, each version of you will record an apparently
>> random sequence of 1s and 0s. Your best prediction of what happens in the
>> next experiment is that it's a 50/50 toss up between 1 and 0. Objectively
>> there's no randomness, subjectively it appears that way.
>>
>>
>>>
>>>
 John K Clark   See my new list at  Extropolis
 

>>> --
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> "Everything List" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to everything-list+unsubscr...@googlegroups.com.
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> 
> .
>

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Re: Born's rule from almost nothing



On Tuesday, January 12, 2021 at 10:19:59 PM UTC-7 Pierz wrote:

>
>
> On Monday, January 4, 2021 at 12:09:06 PM UTC+11 agrays...@gmail.com 
> wrote:
>
>> On Sunday, January 3, 2021 at 3:56:51 PM UTC-7 johnk...@gmail.com wrote:
>>
>>> On Sun, Jan 3, 2021 at 5:21 PM Alan Grayson  wrote:
>>>
>>> *> The MWI doesn't guarantee that these subsequent measurements, for 
 subsequent horse races say, are occurring in the SAME OTHER worlds as 
 trials progress, to get ensembles in those OTHER worlds. *
>>>
>>>  
>>> I don't know what you mean by "SAME OTHER worlds", the same as what? In 
>>> one world Alan Grayson remembers having seen the electron go left, in 
>>> another world Alan Grayson remembers having seen the electron go right, 
>>> other than that the two worlds are absolutely identical, so which one was 
>>> the "SAME OTHER world"?
>>>
>>> > You seem to avoid the fact that no where does the MWI guarantee [...]
>>>
>>>
>>> Quantum mechanics is not in the guarantee business, it deals with 
>>> probability.  
>>>
>>> *> I don't think you understand my point, which isn't complicated. *
>>>
>>>
>>> Yes, your point is very simple indeed, but the word simple can have 2
>>>  meanings, one of them is complementary and the other not so much.  
>>>
>>
>> In first trial, the MWI postulates other worlds comes into existence. 
>> Same other worlds in second trial? Same other worlds in third trial, etc? 
>> Where does the MWI assert these other worlds are the SAME other worlds? 
>> Unless it does, you only have ONE measurement in each of these worlds. No 
>> probability exists in these other worlds since no ensemble of measurements 
>> exist in these other world. AG
>>
>  
> You grossly misunderstand MWI. There are no "same other" worlds. The 
> worlds that arise at each trial are different in precisely one way and one 
> way only: the eigenvalue recorded for the experiment. The different 
> eigenvalues will then give rise to a "wave of differentiations" as the 
> consequences of that singular difference ramifies, causing the different 
> worlds generated by the original experimental difference to multiply. 
> "World" really means a unique configuration of the universal wave function, 
> so two worlds at different trials can't possibly be the "same world", and 
> yes, there is only one measurement in each. 
>
 
*If there is only one measurement in each other world -- which has been my 
claim throughout -- how can Born's rule be satisfied in the MWI? AG*

 

> That is precisely the stipulation of MWI. If we have a quantum experiment 
> with two eigenvalues 1 and 0, and each is equally likely per the Born rule, 
> then the MWI interpretation is that - effectively - two worlds are created. 
> You, the experimenter, end up in both, each version knowing nothing about 
> the other. So, in the "objective world" (the view from outside the whole 
> wave function as it were), no probability is involved. But if you repeat 
> this experiment many times, each version of you will record an apparently 
> random sequence of 1s and 0s. Your best prediction of what happens in the 
> next experiment is that it's a 50/50 toss up between 1 and 0. Objectively 
> there's no randomness, subjectively it appears that way.
>  
>
>>  
>>
>>> John K Clark   See my new list at  Extropolis 
>>> 
>>>
>>

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Re: Born's rule from almost nothing



On Wednesday, January 27, 2021 at 1:04:07 AM UTC-7 Pierz wrote:

> On Wed, 27 Jan 2021 at 6:36 pm, Alan Grayson  wrote:
>
>>
>>
>> On Tuesday, January 26, 2021 at 9:27:43 AM UTC-7 Bruno Marchal wrote:
>>
>>>
>>> On 15 Jan 2021, at 23:34, Alan Grayson  wrote:
>>>
>>> Why not assume the wf applies only before the measurement? 
>>>
>>>
>>> That’s Bohr idea. But it means that measurement are no more describe by 
>>> QM, and this introduces a dualism in the the possible theory of mind that 
>>> you need to use. The élégance if the MWI is that QM applies to both the 
>>> observed and the observer, again, like it has to do assuming mechanism.
>>>
>>>
>>>
>>> Or why not withhold judgement on a phenomenon not yet understood? 
>>> Instead you totally dismiss empirical evidence that no one ever observes a 
>>> split. AG
>>>
>>>
>>> We still observe the result predicted when accepting the superposed wave 
>>> going through all slit. The fact that we don’t feel the split is entirely 
>>> explained by the wave evolution and the self-duplication thought 
>>> experiment. Occam razor favours the simplest conceptual explanation, or we 
>>> add add as many “epicycle” to favour any interpretation, up to the super 
>>> determinism, which I take as an abandon of rationality…
>>>
>>> Bruno
>>>
>>
>> *Yeah, "entirely explained", except for the huge gorilla in the room. 
>> Where's the beef, I mean the energy to create those other worlds? Is it in 
>> the non-computable irrational numbers?  AG*
>>
>
> Another one! It’s a gorilla enclosure! 轢轢轢
>

*Good News! Not the Second Coming of Jesus, but that there is only one copy 
of YOU even if the Cosmos is infinite in spatial extent and time. I don't 
have a rigorous argument, but IMO the density of irrationals in the reals 
is suggestive. No matter the  possible infinities of spatial extent and 
time, you'll never run out of irrationals, each one representing a Cosmos 
with different initial conditions, inclusive of constants. AG*

>
>>>
>>>
>>>
>>>
>>> On Friday, January 15, 2021 at 1:18:53 PM UTC-7 johnk...@gmail.com 
>>> wrote:
>>>
 On Fri, Jan 15, 2021 at 2:22 PM Alan Grayson  
 wrote:


> *> Why do you assume that the initial observer splits after initial 
> trial when it's not observed? AG *


 For heaven sake haven't you been listening?! Because that is the least 
 bizarre interpretation anybody can think of to explain the utterly bizarre 
 results observed from the two slit experiment. There is just no getting 
 around it, if Many Worlds isn't true then something even stranger must 
 be. 

 John K Clark

>

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Re: Born's rule from almost nothing

On Wed, 27 Jan 2021 at 6:36 pm, Alan Grayson  wrote:

>
>
> On Tuesday, January 26, 2021 at 9:27:43 AM UTC-7 Bruno Marchal wrote:
>
>>
>> On 15 Jan 2021, at 23:34, Alan Grayson  wrote:
>>
>> Why not assume the wf applies only before the measurement?
>>
>>
>> That’s Bohr idea. But it means that measurement are no more describe by
>> QM, and this introduces a dualism in the the possible theory of mind that
>> you need to use. The élégance if the MWI is that QM applies to both the
>> observed and the observer, again, like it has to do assuming mechanism.
>>
>>
>>
>> Or why not withhold judgement on a phenomenon not yet understood? Instead
>> you totally dismiss empirical evidence that no one ever observes a split. AG
>>
>>
>> We still observe the result predicted when accepting the superposed wave
>> going through all slit. The fact that we don’t feel the split is entirely
>> explained by the wave evolution and the self-duplication thought
>> experiment. Occam razor favours the simplest conceptual explanation, or we
>> add add as many “epicycle” to favour any interpretation, up to the super
>> determinism, which I take as an abandon of rationality…
>>
>> Bruno
>>
>
> *Yeah, "entirely explained", except for the huge gorilla in the room.
> Where's the beef, I mean the energy to create those other worlds? Is it in
> the non-computable irrational numbers?  AG*
>

Another one! It’s a gorilla enclosure! 轢轢轢

>
>>
>>
>>
>>
>> On Friday, January 15, 2021 at 1:18:53 PM UTC-7 johnk...@gmail.com wrote:
>>
>>> On Fri, Jan 15, 2021 at 2:22 PM Alan Grayson 
>>> wrote:
>>>
>>>
 *> Why do you assume that the initial observer splits after initial
 trial when it's not observed? AG *
>>>
>>>
>>> For heaven sake haven't you been listening?! Because that is the least
>>> bizarre interpretation anybody can think of to explain the utterly bizarre
>>> results observed from the two slit experiment. There is just no getting
>>> around it, if Many Worlds isn't true then something even stranger must
>>> be.
>>>
>>> John K Clark
>>>

>>>
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>> .
>>
>>
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Re: Born's rule from almost nothing

2021-01-26 Thread Alan Grayson



On Tuesday, January 26, 2021 at 9:27:43 AM UTC-7 Bruno Marchal wrote:

>
> On 15 Jan 2021, at 23:34, Alan Grayson  wrote:
>
> Why not assume the wf applies only before the measurement? 
>
>
> That’s Bohr idea. But it means that measurement are no more describe by 
> QM, and this introduces a dualism in the the possible theory of mind that 
> you need to use. The élégance if the MWI is that QM applies to both the 
> observed and the observer, again, like it has to do assuming mechanism.
>
>
>
> Or why not withhold judgement on a phenomenon not yet understood? Instead 
> you totally dismiss empirical evidence that no one ever observes a split. AG
>
>
> We still observe the result predicted when accepting the superposed wave 
> going through all slit. The fact that we don’t feel the split is entirely 
> explained by the wave evolution and the self-duplication thought 
> experiment. Occam razor favours the simplest conceptual explanation, or we 
> add add as many “epicycle” to favour any interpretation, up to the super 
> determinism, which I take as an abandon of rationality…
>
> Bruno
>

*Yeah, "entirely explained", except for the huge gorilla in the room. 
Where's the beef, I mean the energy to create those other worlds? Is it in 
the non-computable irrational numbers?  AG*

>
>
>
>
>
> On Friday, January 15, 2021 at 1:18:53 PM UTC-7 johnk...@gmail.com wrote:
>
>> On Fri, Jan 15, 2021 at 2:22 PM Alan Grayson  wrote:
>>
>>
>>> *> Why do you assume that the initial observer splits after initial 
>>> trial when it's not observed? AG *
>>
>>
>> For heaven sake haven't you been listening?! Because that is the least 
>> bizarre interpretation anybody can think of to explain the utterly bizarre 
>> results observed from the two slit experiment. There is just no getting 
>> around it, if Many Worlds isn't true then something even stranger must 
>> be. 
>>
>> John K Clark
>>
>>>
>>
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>  
> 
> .
>
>
>

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Re: Born's rule from almost nothing

2021-01-26 Thread Alan Grayson



On Tuesday, January 26, 2021 at 9:17:54 AM UTC-7 Bruno Marchal wrote:

>
> On 15 Jan 2021, at 06:01, Alan Grayson  wrote:
>
>
>
> On Thursday, January 14, 2021 at 3:15:47 PM UTC-7, Pierz wrote:
>>
>>
>>
>> On Thursday, January 14, 2021 at 11:07:59 PM UTC+11 agrays...@gmail.com 
>> wrote:
>>
>>> On Thursday, January 14, 2021 at 2:26:42 AM UTC-7 Pierz wrote:
>>>
 On Thursday, January 14, 2021 at 2:42:43 PM UTC+11 agrays...@gmail.com 
 wrote:

> On Wednesday, January 13, 2021 at 8:29:16 PM UTC-7 Pierz wrote:
>
>> On Thursday, January 14, 2021 at 1:23:11 PM UTC+11 
>> agrays...@gmail.com wrote:
>>
>>> On Wednesday, January 13, 2021 at 4:33:20 PM UTC-7 Pierz wrote:
>>>
 On Wednesday, January 13, 2021 at 5:50:29 PM UTC+11 
 agrays...@gmail.com wrote:

> On Tuesday, January 12, 2021 at 10:19:59 PM UTC-7 Pierz wrote:
>
>>
>>
>> On Monday, January 4, 2021 at 12:09:06 PM UTC+11 
>> agrays...@gmail.com wrote:
>>
>>> On Sunday, January 3, 2021 at 3:56:51 PM UTC-7 
>>> johnk...@gmail.com wrote:
>>>
 On Sun, Jan 3, 2021 at 5:21 PM Alan Grayson <
 agrays...@gmail.com> wrote:

 *> The MWI doesn't guarantee that these subsequent 
> measurements, for subsequent horse races say, are occurring in 
> the SAME 
> OTHER worlds as trials progress, to get ensembles in those OTHER 
> worlds. *

  
 I don't know what you mean by "SAME OTHER worlds", the same as 
 what? In one world Alan Grayson remembers having seen the electron 
 go left, 
 in another world Alan Grayson remembers having seen the electron 
 go right, 
 other than that the two worlds are absolutely identical, so which 
 one was 
 the "SAME OTHER world"?

 > You seem to avoid the fact that no where does the MWI 
> guarantee [...]


 Quantum mechanics is not in the guarantee business, it deals 
 with probability.  

 *> I don't think you understand my point, which isn't 
> complicated. *


 Yes, your point is very simple indeed, but the word simple can 
 have 2 meanings, one of them is complementary and the other 
 not so much.  

>>>
>>> In first trial, the MWI postulates other worlds comes into 
>>> existence. Same other worlds in second trial? Same other worlds in 
>>> third 
>>> trial, etc? Where does the MWI assert these other worlds are the 
>>> SAME other 
>>> worlds? Unless it does, you only have ONE measurement in each of 
>>> these 
>>> worlds. No probability exists in these other worlds since no 
>>> ensemble of 
>>> measurements exist in these other world. AG
>>>
>>  
>> You grossly misunderstand MWI. There are no "same other" worlds. 
>> The worlds that arise at each trial are different in precisely one 
>> way and 
>> one way only: the eigenvalue recorded for the experiment. The 
>> different 
>> eigenvalues will then give rise to a "wave of differentiations" as 
>> the 
>> consequences of that singular difference ramifies, causing the 
>> different 
>> worlds generated by the original experimental difference to 
>> multiply. 
>> "World" really means a unique configuration of the universal wave 
>> function, 
>> so two worlds at different trials can't possibly be the "same 
>> world", and 
>> yes, there is only one measurement in each.
>>
>
> This is what I have been saying all along! AG
>
 No it isn't. I agree you have been saying there is only one 
 measurement outcome in each world. However this business about "same 
 other 
 worlds" betrays your lack of comprehension. It's not that MWI "doesn't 
 guarantee" that the the worlds at each trial are the same world. It's 
 that 
 the whole notion of "same other worlds" means nothing in this context 
 and 
 has no bearing on anything. A bit like arguing when we add 1 and 1 
 twice 
 whether we are guaranteed that the ones we add each time are the "SAME 
 ones" at each addition. If mathematics can't guarantee that then how 
 can we 
 be sure the answer is the same? Basically the only answer to that is 
 "WTF?"

>  
>
>> That is precisely the stipulation of MWI. If we have a quantum 
>> experiment with two eigenvalues 1 and 0, and each is equally

Re: Born's rule from almost nothing



> On 16 Jan 2021, at 02:00, smitra  wrote:
> 
> Decoherence should be irrelevant. Whether or not you (considered as some 
> given physical system) have measured something, should not only depend on the 
> entanglement between the measured system and those that belong to you.

Indeed.

Bruno


> 
> Saibal
> 
> On 16-01-2021 00:48, 'Brent Meeker' via Everything List wrote:
>> The Wigner's friend experiment proves a lot less than they headlines
>> hype.
>> The "friends" are quantum 1-degree-of-freedom systems, so they don't
>> decohere, and it's questionable to say they've measured anything.
>> Brent
>> On 1/15/2021 3:27 PM, Alina Gutoreva wrote:
>>> "Before an idea is told, it’s never been true [1]?”-kind of
>>> idea OR “levels [2]”-kind of idea? Or both [3]? I’m confused.
>>> Please, don’t be angry.
>>> Ally
>>> On 15 Jan 2021, at 22:34, Alan Grayson 
>>> wrote:
>>> Why not assume the wf applies only before the measurement? Or why
>>> not withhold judgement on a phenomenon not yet understood? Instead
>>> you totally dismiss empirical evidence that no one ever observes a
>>> split. AG
>>> On Friday, January 15, 2021 at 1:18:53 PM UTC-7 johnk...@gmail.com
>>> [4] wrote:
>>> On Fri, Jan 15, 2021 at 2:22 PM Alan Grayson 
>>> wrote:
 Why do you assume that the initial observer splits after initial
>>> trial when it's not observed? AG
>>> For heaven sake haven't you been listening?! Because that is the
>>> least bizarre interpretation anybody can think of to explain the
>>> utterly bizarre results observed from the two slit experiment. There
>>> is just no getting around it, if Many Worlds isn't true then
>>> something even stranger must be.
>>> John K Clark
>> --
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>> [5].
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>> [6].
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>> [7].
>> Links:
>> --
>> [1]
>> https://www.technologyreview.com/2019/03/12/136684/a-quantum-experiment-suggests-theres-no-such-thing-as-objective-reality/
>> [2] https://t.me/decision_insights/523
>> [3] https://t.me/decision_insights/311
>> [4] http://gmail.com
>> [5]
>> https://groups.google.com/d/msgid/everything-list/2a6bf029-a37a-4049-ab90-0ee889ba9820n%40googlegroups.com?utm_medium=emailutm_source=footer
>> [6]
>> https://groups.google.com/d/msgid/everything-list/5BC6546E-8F24-4D9E-B432-23A92433AB94%40gmail.com?utm_medium=emailutm_source=footer
>> [7]
>> https://groups.google.com/d/msgid/everything-list/0dc3eab3-583d-2c41-d7c7-9dfc8d4f9145%40verizon.net?utm_medium=email_source=footer
> 
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Re: Born's rule from almost nothing

> On 15 Jan 2021, at 23:34, Alan Grayson  wrote:
> 
> Why not assume the wf applies only before the measurement?

That’s Bohr idea. But it means that measurement are no more describe by QM, and 
this introduces a dualism in the the possible theory of mind that you need to 
use. The élégance if the MWI is that QM applies to both the observed and the 
observer, again, like it has to do assuming mechanism.

> Or why not withhold judgement on a phenomenon not yet understood? Instead you 
> totally dismiss empirical evidence that no one ever observes a split. AG

We still observe the result predicted when accepting the superposed wave going 
through all slit. The fact that we don’t feel the split is entirely explained 
by the wave evolution and the self-duplication thought experiment. Occam razor 
favours the simplest conceptual explanation, or we add add as many “epicycle” 
to favour any interpretation, up to the super determinism, which I take as an 
abandon of rationality…

Bruno

> 
> On Friday, January 15, 2021 at 1:18:53 PM UTC-7 johnk...@gmail.com wrote:
> On Fri, Jan 15, 2021 at 2:22 PM Alan Grayson  > wrote:
> 
> > Why do you assume that the initial observer splits after initial trial when 
> > it's not observed? AG 
> 
> For heaven sake haven't you been listening?! Because that is the least 
> bizarre interpretation anybody can think of to explain the utterly bizarre 
> results observed from the two slit experiment. There is just no getting 
> around it, if Many Worlds isn't true then something even stranger must be. 
> 
> John K Clark
> 
> 
> -- 
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>  
> .

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Re: Born's rule from almost nothing


> On 15 Jan 2021, at 06:01, Alan Grayson  wrote:
> 
> 
> 
> On Thursday, January 14, 2021 at 3:15:47 PM UTC-7, Pierz wrote:
> 
> 
> On Thursday, January 14, 2021 at 11:07:59 PM UTC+11 agrays...@gmail.com <> 
> wrote:
> On Thursday, January 14, 2021 at 2:26:42 AM UTC-7 Pierz wrote:
> On Thursday, January 14, 2021 at 2:42:43 PM UTC+11 agrays...@gmail.com <> 
> wrote:
> On Wednesday, January 13, 2021 at 8:29:16 PM UTC-7 Pierz wrote:
> On Thursday, January 14, 2021 at 1:23:11 PM UTC+11 agrays...@gmail.com <> 
> wrote:
> On Wednesday, January 13, 2021 at 4:33:20 PM UTC-7 Pierz wrote:
> On Wednesday, January 13, 2021 at 5:50:29 PM UTC+11 agrays...@gmail.com <> 
> wrote:
> On Tuesday, January 12, 2021 at 10:19:59 PM UTC-7 Pierz wrote:
> 
> 
> On Monday, January 4, 2021 at 12:09:06 PM UTC+11 agrays...@gmail.com <> wrote:
> On Sunday, January 3, 2021 at 3:56:51 PM UTC-7 johnk...@gmail.com <> wrote:
> On Sun, Jan 3, 2021 at 5:21 PM Alan Grayson > wrote:
> 
> > The MWI doesn't guarantee that these subsequent measurements, for 
> > subsequent horse races say, are occurring in the SAME OTHER worlds as 
> > trials progress, to get ensembles in those OTHER worlds. 
>  
> I don't know what you mean by "SAME OTHER worlds", the same as what? In one 
> world Alan Grayson remembers having seen the electron go left, in another 
> world Alan Grayson remembers having seen the electron go right, other than 
> that the two worlds are absolutely identical, so which one was the "SAME 
> OTHER world"?
> 
> > You seem to avoid the fact that no where does the MWI guarantee [...]
> 
> Quantum mechanics is not in the guarantee business, it deals with 
> probability.  
> 
> > I don't think you understand my point, which isn't complicated. 
> 
> Yes, your point is very simple indeed, but the word simple can have 2 
> meanings, one of them is complementary and the other not so much.  
> 
> In first trial, the MWI postulates other worlds comes into existence. Same 
> other worlds in second trial? Same other worlds in third trial, etc? Where 
> does the MWI assert these other worlds are the SAME other worlds? Unless it 
> does, you only have ONE measurement in each of these worlds. No probability 
> exists in these other worlds since no ensemble of measurements exist in these 
> other world. AG
>  
> You grossly misunderstand MWI. There are no "same other" worlds. The worlds 
> that arise at each trial are different in precisely one way and one way only: 
> the eigenvalue recorded for the experiment. The different eigenvalues will 
> then give rise to a "wave of differentiations" as the consequences of that 
> singular difference ramifies, causing the different worlds generated by the 
> original experimental difference to multiply. "World" really means a unique 
> configuration of the universal wave function, so two worlds at different 
> trials can't possibly be the "same world", and yes, there is only one 
> measurement in each.
> 
> This is what I have been saying all along! AG
> No it isn't. I agree you have been saying there is only one measurement 
> outcome in each world. However this business about "same other worlds" 
> betrays your lack of comprehension. It's not that MWI "doesn't guarantee" 
> that the the worlds at each trial are the same world. It's that the whole 
> notion of "same other worlds" means nothing in this context and has no 
> bearing on anything. A bit like arguing when we add 1 and 1 twice whether we 
> are guaranteed that the ones we add each time are the "SAME ones" at each 
> addition. If mathematics can't guarantee that then how can we be sure the 
> answer is the same? Basically the only answer to that is "WTF?"
>  
> That is precisely the stipulation of MWI. If we have a quantum experiment 
> with two eigenvalues 1 and 0, and each is equally likely per the Born rule, 
> then the MWI interpretation is that - effectively - two worlds are created. 
> You, the experimenter, end up in both, each version knowing nothing about the 
> other.
> 
> Again, what I have been saying all along! AG
> If you get that, then the next bit follows. 
>  
> So, in the "objective world" (the view from outside the whole wave function 
> as it were), no probability is involved. But if you repeat this experiment 
> many times, each version of you will record an apparently random sequence of 
> 1s and 0s. Your best prediction of what happens in the next experiment is 
> that it's a 50/50 toss up between 1 and 0. Objectively there's no randomness, 
> subjectively it appears that way.
>  
> Here's where you go astray. AG 
>  
> So you say! Without justifying yourself in any way. You seem to be saying 
> that probability can't describe QM experiments because in each world there is 
> only one outcome and therefore no "ensemble" of outcomes from which a 
> probability can be derived. That is totally wrong-headed. There are two 
> "ensembles": the ensemble of different multiverse branches at each 
> experiment, and the ensemble of each

Re: Born's rule from almost nothing

Pagan theology is just the theology studied with the scientific attitude, which 
means mainly: not invoking revelation (personal or otherwise). It is also 
called “non-confessional theology”. It is theology before tyran appropriates it 
to train the people in obeying to him/her.

The god of Plato is defined by the fundamental truth, or first principle, that 
we can search, with the understanding that anyone claiming to have find it is 
automatically a liar. Something confirmed for the notion of arithmetical truth 
by the universal machine (with enough induction axioms).

Digital Mechanism enforce a coming back to Pythagoreanism, enriched by the 
Church-Turing thesis, which defines the observer internal to the arithmetical 
reality.

Bruno


> On 15 Jan 2021, at 00:10, Philip Benjamin  wrote:
> 
> general_the...@googlegroups.com <mailto:general_the...@googlegroups.com> 
> Subject: [Consciousness-Online] RE: Born's rule from almost nothing
>  
> [Philip Benjamin]
> Be it Relativity Theory (actually Relationality) where Social 
> Sciences ignore the speed of light in vacuo as a CONSTANT (ABSOLUTE) or 
> Quantum Mechanics where mystics disregard the AS IF Logic but accept the BOTH 
> & Fallacy of de Broglie’s wave-like, not Bohr’s wavy, particle, or be it 
> Evolution qua Trans-speciation where the acade-media substitute the 
> un-evidential inter-species Trans-speciation for the evidential intra-species 
> Adaptation or Variation (i.e. Natural Selection), the unproven dogmas of the 
> acade-media have both direct and indirect deleterious effects on social norms 
> in general and current events in particular. They ignore the inevitable 
> questions of aseity, causality, infinite regress, origin, morality, meaning, 
> teleology etc. All dictatorial systems where pagans with reptilian/kundalini, 
> un-awakened consciousnesses dominate, have some or all of these beliefs as 
> their foundations (e.g. pagan Socialist Hitler, pagan Marxist Stalin, pagan 
> Fascist Mussolini and all similar pagan Progressives). Pagan = Pan-Gaian = 
> earthlings for whom earth is all that matters).
>  Western 
> Civilization is an Augustinian Trust
> 
>   Its 
> stealing beneficiary is WAMP-the-Ingrate
> 
>   WAMP = Western Acade-Media 
> Pagan(ism), a parody of the erstwhile WASP
> 
> Paganism, be civilized and scholarly, is un-awakened kundalini 
> consciousness. Non-paganism is awakened, non-reptilian consciousness. Pagan 
> hatred for non-pagans is atavistic, unilateral and universal—pagan Cain vs 
> non-pagan sibling Abel!! The Puritan/Reformation idea of inalienable personal 
> rights for “Life, Liberty and Private Property, as divinely ordained 
> birthrights not bestowed by law, custom, or belief, and which cannot be taken 
> or given away, or transferred to another person, is totally foreign to the 
> WAMP sense of individual freedoms (licentiousness). 
> https://www.bizpacreview.com/2021/01/11/dershowitz-destroys-democrats-impeachment-hopes-1015126/
>  
> <https://www.bizpacreview.com/2021/01/11/dershowitz-destroys-democrats-impeachment-hopes-1015126/>.
>  Modern civilized pagan politicians may impeach all past presidents from 
> George Washington to 46-th.   
> 
>Argumentum verecundiam may use respect for the brilliance and 
> authority of an American physicist Hugh Everett (1957) in order to fortify 
> one’s argument and offer an impression or “hunch” of proof for propositions 
> of questionable validity and reliance such as The Multiverse speculation that 
> “there are many worlds which exist in parallel at the same space and time as 
> our own”. Here, the Schrodinger equation never collapses, but all 
> probabilities of a quantum superstition are objectively real,  unlike the 
> subjective CopenPagan Interpretation (a malaprop for Copenhagen!).  This 
> makes it possible to remove randomness and action at a distance from quantum 
> theory, but that does not make it true. Quantum theory interpretations, be it 
> the subjective CopenPagan or objective Many Worlds, are based on imaginary 
> conceptualization of particle-wave duality. De Broglie wave-length is based 
> only on apparent wave-likeness not actual waviness of particles. An AS IF 
> Logic, not Both & Fallacy, is all that is needed here.
>Photons also are corpuscular, probably with mas at an indefinite 
> decimal place, behaving AS IF in wave forms. Corpuscular photon and 
> particulate matter are very differently treated.  In 1905 Einstein managed to 
> write E^2=P^2c^2+m^2c^4,and he figured out that light is both a particle and 
> a wave and that

Re: Born's rule from almost nothing


> On 14 Jan 2021, at 13:07, Alan Grayson  wrote:
> 
> 
> 
> On Thursday, January 14, 2021 at 2:26:42 AM UTC-7 Pierz wrote:
> On Thursday, January 14, 2021 at 2:42:43 PM UTC+11 agrays...@gmail.com 
>  wrote:
> On Wednesday, January 13, 2021 at 8:29:16 PM UTC-7 Pierz wrote:
> On Thursday, January 14, 2021 at 1:23:11 PM UTC+11 agrays...@gmail.com <> 
> wrote:
> On Wednesday, January 13, 2021 at 4:33:20 PM UTC-7 Pierz wrote:
> On Wednesday, January 13, 2021 at 5:50:29 PM UTC+11 agrays...@gmail.com <> 
> wrote:
> On Tuesday, January 12, 2021 at 10:19:59 PM UTC-7 Pierz wrote:
> 
> 
> On Monday, January 4, 2021 at 12:09:06 PM UTC+11 agrays...@gmail.com <> wrote:
> On Sunday, January 3, 2021 at 3:56:51 PM UTC-7 johnk...@gmail.com <> wrote:
> On Sun, Jan 3, 2021 at 5:21 PM Alan Grayson > wrote:
> 
> > The MWI doesn't guarantee that these subsequent measurements, for 
> > subsequent horse races say, are occurring in the SAME OTHER worlds as 
> > trials progress, to get ensembles in those OTHER worlds. 
>  
> I don't know what you mean by "SAME OTHER worlds", the same as what? In one 
> world Alan Grayson remembers having seen the electron go left, in another 
> world Alan Grayson remembers having seen the electron go right, other than 
> that the two worlds are absolutely identical, so which one was the "SAME 
> OTHER world"?
> 
> > You seem to avoid the fact that no where does the MWI guarantee [...]
> 
> Quantum mechanics is not in the guarantee business, it deals with 
> probability.  
> 
> > I don't think you understand my point, which isn't complicated. 
> 
> Yes, your point is very simple indeed, but the word simple can have 2 
> meanings, one of them is complementary and the other not so much.  
> 
> In first trial, the MWI postulates other worlds comes into existence. Same 
> other worlds in second trial? Same other worlds in third trial, etc? Where 
> does the MWI assert these other worlds are the SAME other worlds? Unless it 
> does, you only have ONE measurement in each of these worlds. No probability 
> exists in these other worlds since no ensemble of measurements exist in these 
> other world. AG
>  
> You grossly misunderstand MWI. There are no "same other" worlds. The worlds 
> that arise at each trial are different in precisely one way and one way only: 
> the eigenvalue recorded for the experiment. The different eigenvalues will 
> then give rise to a "wave of differentiations" as the consequences of that 
> singular difference ramifies, causing the different worlds generated by the 
> original experimental difference to multiply. "World" really means a unique 
> configuration of the universal wave function, so two worlds at different 
> trials can't possibly be the "same world", and yes, there is only one 
> measurement in each.
> 
> This is what I have been saying all along! AG
> No it isn't. I agree you have been saying there is only one measurement 
> outcome in each world. However this business about "same other worlds" 
> betrays your lack of comprehension. It's not that MWI "doesn't guarantee" 
> that the the worlds at each trial are the same world. It's that the whole 
> notion of "same other worlds" means nothing in this context and has no 
> bearing on anything. A bit like arguing when we add 1 and 1 twice whether we 
> are guaranteed that the ones we add each time are the "SAME ones" at each 
> addition. If mathematics can't guarantee that then how can we be sure the 
> answer is the same? Basically the only answer to that is "WTF?"
>  
> That is precisely the stipulation of MWI. If we have a quantum experiment 
> with two eigenvalues 1 and 0, and each is equally likely per the Born rule, 
> then the MWI interpretation is that - effectively - two worlds are created. 
> You, the experimenter, end up in both, each version knowing nothing about the 
> other.
> 
> Again, what I have been saying all along! AG
> If you get that, then the next bit follows. 
>  
> So, in the "objective world" (the view from outside the whole wave function 
> as it were), no probability is involved. But if you repeat this experiment 
> many times, each version of you will record an apparently random sequence of 
> 1s and 0s. Your best prediction of what happens in the next experiment is 
> that it's a 50/50 toss up between 1 and 0. Objectively there's no randomness, 
> subjectively it appears that way.
>  
> Here's where you go astray. AG 
>  
> So you say! Without justifying yourself in any way. You seem to be saying 
> that probability can't describe QM experiments because in each world there is 
> only one outcome and therefore no "ensemble" of outcomes from which a 
> probability can be derived. That is totally wrong-headed. There are two 
> "ensembles": the ensemble of different multiverse branches at each 
> experiment, and the ensemble of each experimenter's prior measurements, and 
> those are enough to derive the appearance of randomness and to justify a 
> probabilistic description despite the

Re: Born's rule from almost nothing


> On 12 Jan 2021, at 16:48, Alan Grayson  wrote:
> 
> 
> 
> On Tuesday, January 12, 2021 at 5:41:07 AM UTC-7 Alan Grayson wrote:
> On Tuesday, January 12, 2021 at 5:26:50 AM UTC-7 Bruno Marchal wrote:
> 
>> On 3 Jan 2021, at 03:43, Alan Grayson > wrote:
>> 
>> 
>> 
>> On Saturday, January 2, 2021 at 2:17:12 AM UTC-7 johnk...@gmail.com 
>>  wrote:
>> On Fri, Jan 1, 2021 at 5:35 PM 'Brent Meeker' via Everything List 
>> > wrote:
>> 
>> >> Assuming that Many Worlds is true and the multiverse is completely 
>> >> determined by Schrodinger's equation and there are therefore an 
>> >> astronomically large number (perhaps an infinite number) of Bruce 
>> >> Kelletts with microscopic or submicroscopic differences between them, and 
>> >> those Bruce Kelletts were observing a stream of photons polarized at 
>> >> angle X hit a polarizing filter set to angle X+Y; would any one of those 
>> >> Bruce Kelletts be able to predict with certainty that Bruce Kellett would 
>> >> or would not observe the photon pass through that filter? No. Would Bruce 
>> >> Kellett have to resort to probability? Yes. How would Bruce Kellett 
>> >> calculate the probability? If Bruce Kellett wanted to avoid logical self 
>> >> contradictions there is only one method Bruce Kellett could use, the Born 
>> >> Rule.
>> 
>> > I don't think that's quite true.  Suppose for example BK decided to 
>> > predict that the polarization with the highest value of |psi|^2 is the one 
>> > that would pass thru. He wouldn't run into any logical contradiction 
>> > because he's not interpreting it as probability,
>> 
>> If the BKs are Interpreting that as a certainty and not a probability then 
>> the BKs wouldn't run into a logical contradiction but they would run into an 
>> empirical one because that wouldn't match experimental observation. It's 
>> entirely possible that a BK's prediction would fail and that the high 
>> |psi|^2 photon would NOT make it through (unless the value happened to be 
>> exactly 1), and even if the prediction turned out to be correct scientific 
>> experiments must be repeatable and when the BKs conduct it over and over 
>> again all the BKs will soon find out that the predictions tend to be correct 
>> |psi|^2 of the time.
>> 
>>  > he wouldn't run into an empirical contradiction unless he assumed the 
>> actual process was producing a probability distribution and so he needed to 
>> predict a distribution and not just a value. 
>> 
>> But the BKs didn't assume it was a probability distribution, they discovered 
>> it was. If the BKs assumed the |psi|^2 value was just a number and not a 
>> probability and had no physical significance then the BKs would soon 
>> discover that the assumption was wrong
>>   
>> > Once you know that you need a probability distribution from the wave 
>> > function...then Born's rule is the only choice. 
>> 
>> Yes.
>>  
>> > But it's the step from the wave-function and "everything happens" to a 
>> > probability distribution where MWI leaves a gap.
>> 
>> I don't see the gap. If Many Worlds was true then what would the Brent 
>> Meekers interpret |psi|^2 to mean? If it's just a number and means nothing 
>> then solving Schrodinger's equation would be a waste of time because that 
>> equation would also mean nothing, it should be ignored; but then we wouldn't 
>> have transistors or lasers or about 6.02*10^23 other things in modern life. 
>> 
>> The gap Brent refers to has nothing to do with Schrodinger's equation, as I 
>> previously explained. Every trial in an experiment can be interpreted as a 
>> separate horse race, creating its own set of worlds where each possible 
>> occurrence is allegedly measured. But on subsequent trials, the MWI gives no 
>> guarantee that the same set of worlds is created. IOW, without another 
>> postulate appended to the MWI, each world is associated with exactly ONE 
>> measurement. No ensembles in these worlds; hence, the necessary condition 
>> for a probability doesn't exist. AG. 
> 
> The born rule must be applied, and it concerns the relative accessible 
> histories. It is better to avoid the term “world” which is hard to define.
> 
> Accessible to who, or to what? AG 
> 
> IMO, it's impossible to avoid using the term "world". After all, the MWI 
> depends on the claim that everything that CAN happen, MUST happen. IOW, every 
> possible measurement MUST be measured, somewhere, somehow. Can you measure an 
> event without an observer and measuring device? The "observer" doesn't have 
> to be human. It could be an instrument. But whatever it is, it surely DOES 
> imply a "world" of some sort, partially or fully.  And once you admit that 
> other "worlds" necessarily come into existence given the core assumption on 
> which the MWI depends, the entire structure of the interpretation falls away, 
> into absurdity; e.g., where is the energy to create these worlds? AG

To be short: in the mind of the universal number, which lives in arithmetic.

Re: Born's rule from almost nothing