On 2/26/2015 8:01 PM, Jason Resch wrote:
On Thu, Feb 26, 2015 at 9:51 PM, meekerdb <meeke...@verizon.net <mailto: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 <mailto:meeke...@verizon.net>> wrote: On 2/26/2015 3:16 PM, LizR wrote:On 27 February 2015 at 10:01, meekerdb <meeke...@verizon.net <mailto: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.
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 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. But notice that all these "worlds" need to already exist. 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.
Does the size of the infinity matter?A continuum would be better because is has a natural measure.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.
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