On 27 Feb 2015, at 06:57, Jason Resch wrote:
On Thu, Feb 26, 2015 at 10:21 PM, meekerdb <meeke...@verizon.net>
wrote:
On 2/26/2015 8:01 PM, Jason Resch wrote:
On Thu, Feb 26, 2015 at 9:51 PM, meekerdb <meeke...@verizon.net>
wrote:
On 2/26/2015 7:10 PM, Jason Resch wrote:
On Thu, Feb 26, 2015 at 5:57 PM, meekerdb <meeke...@verizon.net>
wrote:
On 2/26/2015 3:16 PM, LizR wrote:
On 27 February 2015 at 10:01, meekerdb <meeke...@verizon.net>
wrote:
MWI predicts the same as QM+collapse.
Only because it assumes the Born rule applies to give a
probability interpretation to the density matrix. But
Everettista's either ignore the need for the Born rule or they
suppose it can be derived from the SWE (although all attempts
have fallen short).
This is an important point. Do any interpretations explain the
Born rule? If so, that would be a reason to prefer them to the MWI.
Gleason's theorem says the Born rule is the only consistent way to
assign probabilities to states in Hilbert space (showing Born had
good intuition).
So then the mystery of the Born rule is solved. I don't see why/
how adding collapse solves anything.
I adds that one of the probable states happens. MWI fails to add
that.
Isn't it enough when one considers the FPI (which tells us you will
only experience one of the probable states)?
Maybe. It depends on "your" experience being a classical process
and the "worlds" being classical.
Why can't I be a classical computation within a quantum environment?
Like as Ron Garrett put it "I am a simulation running on a quantum
computer."
But there is no problem with "me" being quantum. This is allowed with
comp, although there is no evidence for it, and rather evidence for
the contrary. The elementary arithmetic does contain all quantum
computations, on the rational numbers, and the FPI can justify the
reals and complex numbers (I mean the infinite decimal, in case they
have a role). It would make the first person plural more non-
computable, and I doubt this is real, but it does not lead to
conceptual difficulties, I think.
Bruno
We only experience one point in time and one place in space, but
that doesn't mean the other times and place don't exist, even if
there are an infinite number of other times and places to
experience (in fact there may be an infinite number of places you
exist, if space is infinite and uniform). So I fail to see the
special distinction of copies of myself in the wave function.
So by your lack of comment, can I infer you agree there is no import
distinction?
So if you can justify placing a measure on the multiple worlds it
has to be Born's rule. The problem seems to be that branch
counting doesn't make sense unless the number of branches are
infinite.
Why is that?
Branch counting for an up/down measure of a spin 1/2 requires two
branches: one up and one down. But if an instrument bias is added
so the probabilities are 0.501 up and 0.499 down, a thousand
branches are needed.
But how do you get from that to concluding there are an infinite
number of branches (rather than just some very large number)?
I just use 'infinite' to mean a very large arbitrary number.
So why is this a problem for conventional probability?
But notice that all these "worlds" need to already exist.
Why? Can one really decided between subjective differentiation vs.
objective splitting?
Leonard Susskind likes this - because he wants the string theory
landscape to exist.
But if they're infinite it's not clear how to define the measure.
Why is that?
Because probabilities are M/N where N is the number of possibilities.
But what if M and N are measures? Consider the infinite reals
between 0.2 and 0.3, there are an infinite number of reals, yet
they comprise only 10% of the range from 0.0 to 1.0.
That's what I meant by the continuum has a natural measure.
So is that a possibility then? That there are non-denumerable
worlds? This seemed to be a conclusion among leading physicists when
Everett presented his theory to them.
Does the size of the infinity matter?
A continuum would be better because is has a natural measure.
So then why is there so much fuss over probabilities not making sense?
Perhaps taking the limit of branch counting as the number of UD
threads goes to infinity would work, but that seems non-Platonic
since it would rely the threads coming into existence as on a
concrete UD.
This is separate (I think) from the basis problem. Under a
computationalist theory of mind it would seem that you need to
define bases with eigenvectors like, "I see the needle pointing
up." But we only know (approximately) how to define eigenvectors
for the needle.
Would it be equivalent to the eigenvector of the needle pointing
up and you looking at it?
That's what is assumed in practice, i.e. that the needle collapses/
splits the state. But then the question is why the needle? The
needle was moved by a electromagnet...which was driven by a
current...which came from a photoamplifier tube...which was excited
by an electron. But all that instrumentation could be in a
superposition (and as Bruce points out, ARE in a superposition in
some other basis).
And remain in a superposition, forever. But there's little
interference between the parts of the wave function realizing
different brain states( which realize different conscious states).
That depends on the choice of basis. And in some choice of the
basis the instruments all have little interference between different
measurement states - but the instrument+environment still has
interference terms.
Is this the same concept of "jellification" that Schrodinger worried
about? Didn't someone resolve that?
Sean Boocock observes that in modern quantum mechanics (due to
decoherence) "the weird jellification that Schrodinger worries about
does not come about on large scales simply because the probability
of us ever being able to perceive it is too phenomenally low."
Jason
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