On 22 Nov 2017, at 09:55, agrayson2...@gmail.com wrote:
On Tuesday, November 21, 2017 at 12:43:05 PM UTC-7, Bruno Marchal
wrote:
On 20 Nov 2017, at 20:40, agrays...@gmail.com wrote:
On Monday, November 20, 2017 at 6:56:52 AM UTC-7, Bruno Marchal
wrote:
On 18 Nov 2017, at 21:32, agrays...@gmail.com 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? 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.
Without collapse, the measurement are described by the quantum laws.
That's precisely what QM doesn't describe, which constitutes part of
the measurement problem. AG
Just see above. QM describes precisely why the observers believe
correctly (with respect to their first person notion) having done
measurement, and got precise outcomes, but from the 3p waves
perspectives, all we have is a structured collection of relative
states (which all exists and are structured in arithmetic, BTW).
An observer along a superposition up + down, *is* the same state as
the observer along up superposed with the observer down, if he look
in the {up + down, up - down} basis, "he" will see he is in up+down,
but if he looks in the {up down} basis; the observer consciousness
differentiate, in his first person perspective, but the solution of
the wave describes the two outcomes realized from the point of view
of each observer. You can't decide to make one of them into a zombie.
I have no idea what you mean. Please try again. AG
The tensor product is linear, so A(up + down) = (A up) + (A down). OK?
the evolution is linear and when A looks at the particle: she is
described by (A-up up) + (A-down down). (with of course 1/sqrt(2)
everywhere).
the consciousness of A has differentiated into (A-up) and (A-down).
With Bohr, one among A-up and A-down mysteriously disappears. With
Bohm (one world + a potential simulating the entire Many-world, but
"without particles") one among A-up and A-down becomes a zombie, even
one lacking a body made of particles, yet, the waves describes them as
being alive like you and me, and we can test it (in principle) by
making quantum computation with oneself.
So I see an additional assumption in the MWI. AG
I disagree, and Everett would disagree. I am aware most people
claims Everett and Copenhagen are differet intepretations, but from
a metamathematical obvious view: Everett and Copenhagen are
different theories.
They have identical postulates but Everett adds another non-trivial
one as I indicated above; namely, that every possible measurement is
realized, that is measured, in another world. I don't see why you
insist on denying something so obvious. AG
?
I think you should read Everett. he propose a new formulation of QM,
and it is copenhagen with the withdrawal of the collapse postulate.
All measurement are realized in the sense that no superposition ever
collapse, but that it looks in that way from the first person
perspective of the observer. he reduces the quantum indeterminacy to
the classical self-indetermination based on amoeba-like duplication.
The only problem is that his task is not finished: by using mechanism
(as he recognizes explicitly in his long text) he must take into
account all computations, not just the quantum one. in other word, the
wave itself must be recovered, and indeed the math indicates that is
possible, as quantum logics appears at the place where such task must
be handled.
Everett is the SWE, and Copenhagen is SWE + collapse. We might
accept that Everett theory has not yet justify all aspects of what
could be the physical reality (and provably so if we assume digital
mechanism in cognitive science), but, to be short, it is less crazy
than any theory making the collapse into a physical phenomenon.
Why crazy? What we seem to observe IS collapse;
yes. but that is the whole difference between a platonist and an
aristotelian. The aristotelian define reality by what they see. The
platonist define reality by whatever makes us to believe that we see
something.
And we do not observe a collapse/ We observe a cat, or something.
Exactly like the wave without collapse, + a mechanist theory of mind,
predicts.
Everett just soleved the mind-body problem, at the conceptual level.
And partially, because my contribution here is that this *has to be*
prolongated in arithmetic, and the wave must be justified itself by a
statistic on all computations. It works at the proposition level: it
gives quantum logic at the place of propositional physics.
that is, all probabilities evolving to zero except the measured
probability evolving to 1, by an as-yet unknown physical process. AG
A unknown physical phenomenon that Einstein criticized already in
1927, by showing that the collapse would need to be non covariant. The
wave has to vanish instantaneously. With the many-worlds, there is no
problem at all for the easy 1927 thought experience: the wave never
vanishes, but you localize yourself on which branch you are in the
superposition.
The measurement problem exists only when we associate a unique outcome
for the experiment. With Everett, measurement are explained by
interaction+entanglement. decoherence then explains why we can't see
the "other branches".
I know that Bruce and Clark disagree, but in my opinion, Everett (non-
collapse) solves all the conceptual problems that Einstein disliked so
much in QM. We get a reversible deterministic local physical "big
picture".
Now, with mechanism, this leads to no universe at all, in the
aristotelian sense of the words, as the "physical universe", the wavy
multiverse of Everett-Deutsch, has to be itself the winner in a deeper
game played by all computations (which exists in elementary
arithmetic). "All computations" is a very solid notions, thanks to
Gödel's theorem which protects Church's thesis and Mechanism from a
vast collection of reductionist philosophy.
Bruno
I reject this hypothesis. What I do concede is that in the case of
the Multiverse of String Theory, if time is infinite and the
possible universes finite -- 10^500 -- all possible universes will
be, or have been, realized. AG
OK, but that is not Everett-Deustch "multiverse" (relative state,
many-worlds, etc.).
Too much parsing! I was trying to explain that the Multiverse of
String Theory is manifestly *different* from the Many Worlds of the
MWI. AG
Yes. you are right on this. In string theory with collapse (if this
could even make sense), you have 10^500 physical realities. In
string theory without collapse, you have (10^500 * Infinity)
physical realities, at first sight (with mechanism they are just
"coherent dreams" (sigma_1 true sentences seen in the Bp & ~Bf mode)
by Numbers).
Bruno
Bruno
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