On 23 Nov 2017, at 23:48, [email protected] wrote:
On Wednesday, November 22, 2017 at 2:51:56 PM UTC-7,
[email protected] wrote:
On Wednesday, November 22, 2017 at 5:24:48 PM UTC, Bruno Marchal
wrote:
On 22 Nov 2017, at 09:55, [email protected] wrote:
On Tuesday, November 21, 2017 at 12:43:05 PM UTC-7, Bruno Marchal
wrote:
On 20 Nov 2017, at 20:40, [email protected] wrote:
On Monday, November 20, 2017 at 6:56:52 AM UTC-7, Bruno Marchal
wrote:
On 18 Nov 2017, at 21:32, [email protected] wrote:
On Saturday, November 18, 2017 at 1:17:25 PM UTC-7, Brent wrote:
On 11/18/2017 8:58 AM, John Clark wrote:
> I think "must" is unwarranted, certainly in the case of
the MWI. Rather, it ASSUMES all possible measurements must be
realized in some world. I see no reason for this
assumption other than an insistence to fully reify
the wf in order to avoid "collapse".
The MWI people don't have to assume anything because there is
absolutely nothing in t he Schrodinger Wave E
quation about collapsing, its the Copenhagen people
who have to assume that somehow it does.
It's not just an assumption. It's an observation. The SE alone
didn't explain the observation, hence the additional ideas.
Brent
Moreover, MWI DOES make additional assumptions, as its name
indicates, based on the assumption that all possible measurements
MUST be measured, in this case in other worlds.
That is not an assumption. It is the quasi-literal reading of the
waves. It is Copenhagen who added an assumption, basically the
assumption that the wave does not apply to the observer: they
assumed QM was wrong for the macroscopic world (Bohr) or for the
conscious mind (Wigner, von Neumann) depending where you put the
cut.
CMIIAW, but I see it, the postulates tell us the possible results
of measurements. They don't assert that every possible measurement
will be realized.
What do you mean by realize?
Realized = Measured. AG
Measured by who?
Doesn't this identical question come up in MWI, but with Many Worlds
the problem seems to metastasize. AG
Not really. With the MWI the problem is partially solved with the
Mechanist first person indeterminacy or weakening of i. The only
problem, in case we use the first person mechanist indterminacy is
that we have to extract the quantum wave itself from elementary
arithmetic and its internal logics of self-reference. That has been
done partially, and up to now the results are confirmed by nature. For
this I suggest you read my papers.
More precisely, if Alice look at a particle is state up+down: the
wave is A(up + down) = A up + A down. Then A looks at the particles.
The waves evolves into A-saw-up up + A-saw-down down. Are you OK to
say that a measurement has occurred? Copenhagen says that the
measurement gives either A-saw-up up or A-saw-up down, but that
NEVER occurs once we abandon the collapse. So without collapse, a
measurement is a first person experience. In this case, it is
arguably the same as the experience of being duplicated.
If you could revise your reply using the wf of the singlet state
(without the normalizing factor) in the following form, I might be
able to evaluate your analysis; namely, ( |UP>|DN> - |DN>|UP> ).
I think I have done this in some later post.
I believe you have misapplied tensor linearity. TIA, AG
Where?
Without collapse, the measurement are described by the quantum laws.
That's precisely what QM doesn't describe, which constitutes part
of the measurement problem. AG
Just see above. QM describes precisely why the observers believe
correctly (with respect to their first person notion) having done
measurement, and got precise outcomes, but from the 3p waves
perspectives, all we have is a structured collection of relative
states (which all exists and are structured in arithmetic, BTW).
An observer along a superposition up + down, *is* the same state as
the observer along up superposed with the observer down, if he look
in the {up + down, up - down} basis, "he" will see he is in up
+down, but if he looks in the {up down} basis; the observer
consciousness differentiate, in his first person perspective, but
the solution of the wave describes the two outcomes realized from
the point of view of each observer. You can't decide to make one of
them into a zombie.
I have no idea what you mean. Please try again. AG
The tensor product is linear, so A(up + down) = (A up) + (A down). OK?
But this doesn't appear in singlet state, and I don't see why it is
relevant. How can an observer can be in a superposed state? It's the
system which is in a superposed state, which is never observed
AFAIK. AG
Hmm... you seem to endorse Bohr's dualist split of the subject, which
is exactly what the MWI avoid. The observer is described by by QM, as
is the system "observer + observed". Linearity of evolution of the
state and of the tensor product assures this, and we recover the
statistics from Gleason theorem + the first person Mechanist
indeterminacy (self-splitting). There is no real other option once we
want apply quantum physics to cosmology. Eventually, we lose "only"
the physical universe and physicalism, as we have to extract the wave
itself from the first person plural observable defined by the
universal machine. The quantum aspect of nature is how elementary
arithmetic appears from inside internal first person view.
the evolution is linear and when A looks at the particle: she is
described by (A-up up) + (A-down down). (with of course 1/sqrt(2)
everywhere).
the consciousness of A has differentiated into (A-up) and (A-down).
With Bohr, one among A-up and A-down mysteriously disappears. With
Bohm (one world + a potential simulating the entire Many-world, but
"without particles") one among A-up and A-down becomes a zombie,
even one lacking a body made of particles, yet, the waves describes
them as being alive like you and me, and we can test it (in
principle) by making quantum computation with oneself.
So I see an additional assumption in the MWI. AG
I disagree, and Everett would disagree. I am aware most people
claims Everett and Copenhagen are differet intepretations, but from
a metamathematical obvious view: Everett and Copenhagen are
different theories.
They have identical postulates but Everett adds another non-trivial
one as I indicated above; namely, that every possible measurement
is realized, that is measured, in another world. I don't see why
you insist on denying something so obvious. AG
?
I think you should read Everett. he propose a new formulation of QM,
and it is copenhagen with the withdrawal of the collapse postulate.
OK, Everett removes collapse, but adds the postulate that every
possible outcome is measured in some other world. Breathtaking, and
as I stated above non-trivial. See my remarks in last post to Clark.
AG
It is not so astonishing. I expected this from the digital mechanist
hypothesis even before realizing that quantum mechanics implements
this. This is simply due to the (not so well known) fact that all
computations are run in elementary arithmetic (EA). EA provides a
block-many-worlds, although it is more a block-many computations.
All measurement are realized in the sense that no superposition ever
collapse, but that it looks in that way from the first person
perspective of the observer. he reduces the quantum indeterminacy to
the classical self-indetermination based on amoeba-like duplication.
The only problem is that his task is not finished: by using
mechanism (as he recognizes explicitly in his long text) he must
take into account all computations, not just the quantum one. in
other word, the wave itself must be recovered, and indeed the math
indicates that is possible, as quantum logics appears at the place
where such task must be handled.
Everett is the SWE, and Copenhagen is SWE + collapse. We might
accept that Everett theory has not yet justify all aspects of what
could be the physical reality (and provably so if we assume digital
mechanism in cognitive science), but, to be short, it is less crazy
than any theory making the collapse into a physical phenomenon.
Why crazy? What we seem to observe IS collapse;
yes. but that is the whole difference between a platonist and an
aristotelian. The aristotelian define reality by what they see. The
platonist define reality by whatever makes us to believe that we see
something.
So by your lights "arithmetic" or "computation" leads us to reality,
whereas the physical world is an illusion? -- a bold thesis but IMO
unlikely. AG
It is a theorem in the Mechanist theory of cognition. You need to add
some magic in the "physical reality" to give it a way to distinguish
itself from the statistics on all computations.
And we do not observe a collapse/ We observe a cat, or something.
Exactly like the wave without collapse, + a mechanist theory of
mind, predicts.
Everett just soleved the mind-body problem, at the conceptual level.
And partially, because my contribution here is that this *has to be*
prolongated in arithmetic, and the wave must be justified itself by
a statistic on all computations. It works at the proposition level:
it gives quantum logic at the place of propositional physics.
that is, all probabilities evolving to zero except the measured
probability evolving to 1, by an as-yet unknown physical process. AG
A unknown physical phenomenon that Einstein criticized already in
1927, by showing that the collapse would need to be non covariant.
Proof? Reference? TY, AG
That is well detailed in my french book "Physique atomique et
connaissance humaine", and that specific part (Discussion avec
Einstein sur des problèmes épistémologiques de la physique atomique"
has been translated from the tome VII of "The Liabray of Living
philosophers", Evanston, 1949, p. 199.
Normally this is also in most good selector papers on the early paper
on the foundation of QM. It should be in the selected papers by
Wheeler and Zurek in the Princeton Series in Physics.
The wave has to vanish instantaneously.
If a probability wave is non physical, it could do so without
contradiction. AG
The problem is that if the probability amplitude is not a physical
wave, we can't explained the interference obtained in Young two split
experience when the particles are send one by one. The whole weirdness
of QM comes from this. Now, I can agree with you that the
probabilities are not physical, but subjective, but then, to keep the
quantum prediction, the collapse appareance itself is not physical and
we are back to the MW or the many computations.
With the many-worlds, there is no problem at all for the easy 1927
thought experience: the wave never vanishes, but you localize
yourself on which branch you are in the superposition.
The measurement problem exists only when we associate a unique
outcome for the experiment. With Everett, measurement are explained
by interaction+entanglement. decoherence then explains why we can't
see the "other branches".
Unless you can reasonably describe the content of these other
worlds, as implied by my last post to Clark, you seem to be in a
world of hurt (in this world btw). AG
Well, if I measure the spin of an electron up+down with a Stern-
Gerlach device, the content of the "parallel worlds " are well know:
it is the same content as this one world I live, except I found the
electron in the opposite spin. Of course, if I decided to take some
holiday in Spain or in Finland according to the spin found, the
"universe" differentiates into one in which I take holiday in Spain,
and one in Finland, and similar with all physical consequences.
(Now, with mechanism in mind, it is preferable to say that it is
consciousness and the first person plural views which differentiate,
as there is no "physical universe" well defined per se.
Bruno
I know that Bruce and Clark disagree, but in my opinion, Everett
(non-collapse) solves all the conceptual problems that Einstein
disliked so much in QM. We get a reversible deterministic local
physical "big picture".
Now, with mechanism, this leads to no universe at all, in the
aristotelian sense of the words, as the "physical universe", the
wavy multiverse of Everett-Deutsch, has to be itself the winner in a
deeper game played by all computations (which exists in elementary
arithmetic). "All computations" is a very solid notions, thanks to
Gödel's theorem which protects Church's thesis and Mechanism from a
vast collection of reductionist philosophy.
Bruno
I reject this hypothesis. What I do concede is that in the case
of the Multiverse of String Theory, if time is infinite and the
possible universes finite -- 10^500 -- all possible universes
will be, or have been, realized. AG
OK, but that is not Everett-Deustch "multiverse" (relative state,
many-worlds, etc.).
Too much parsing! I was trying to explain that the Multiverse of
String Theory is manifestly *different* from the Many Worlds of
the MWI. AG
Yes. you are right on this. In string theory with collapse (if this
could even make sense), you have 10^500 physical realities. In
string theory without collapse, you have (10^500 * Infinity)
physical realities, at first sight (with mechanism they are just
"coherent dreams" (sigma_1 true sentences seen in the Bp & ~Bf
mode) by Numbers).
Bruno
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