Many Worlds Interpretation and act of measuring

  • #451
RUTA
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If you're right then the problem doesn't away in any interpretation that admits of superposed states even momentarily. However, I don't know why it is a problem if each state defines its own manifold. Obviously it all becomes much more complicated but that's going to happen in any theory that includes GR.
What would superposition look like in Wheeler-deWitt? Each Hilbert space vector would represent a single spacetime manifold, metric and stress-energy tensor with no "meta" time dependence, i.e., the vector would not change or evolve.

If you're a psi-epistemist, then you might view MW as simply supplying the time-evolved 3D embedded view of a subset of all flat spacetime solutions in Wheeler-deWitt. In that sense, MW actually fits nicely with quantum gravity.

I'm sure MWers have considered this, so I was hoping someone here might explain it :-)
 
  • #452
stevendaryl
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Prove it then and win a Nobel Prize.

So far there is pretty much no agreement amongst even supporters of MWI in terms of how to solve preferred basis problem and Born Rule problem. Yougot no solution either. You sounds borderline religious with this dogmatic "WE ARE"
I think your tone is way out of line. There is nothing "religious" about what Derek said.

There is a tendency in physics discussions for people to be insultingly certain about subjects that are understood the least. People don't understand the foundations of quantum mechanics, the meaning of measurement, the origin of probabilities very well at all, but everyone has a strong opinion that other people's views are nonsense.

Everett's original paper about MWI was mostly about exploring the question: What if in quantum mechanics we treat the measuring device (or observer) quantum-mechanically? That's not only a non-silly thing to ask, it seems required if we are to take quantum mechanics seriously as a foundation for physics. MWI in this sense is the insistence that there NOT be anything magical going on in the measurement process. That's an assumption, but it's hardly a "religious" assumption.
 
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  • #453
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I think your tone is way out of line. There is nothing "religious" about what Derek said.
My tone is a replication of his own tone. He is being condescending to everyone that isn't a member of his 'MWI religion' here by calling them "silly". He has already stated that it *is* true, with no solution to the current problems and absolutely no evidence.
 
  • #454
stevendaryl
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My tone is a replication of his own tone. He is being condescending to everyone that isn't a member of his 'MWI religion' here by calling them "silly". He has already stated that it *is* true, with no solution to the current problems and absolutely no evidence.
You're way out of line. What he's describing is not "religious".
 
  • #455
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You're way out of line. What he's describing is not "religious".
CLAIMING that something unprovable that directly disagrees with observation IS TRUE is indeed the definition of 'borderline religious'
 
  • #456
stevendaryl
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CLAIMING that something unprovable that directly disagrees with observation IS TRUE is indeed the definition of 'borderline religious'
No, it isn't. It has nothing to do with religion. Your posts are way out of line.
 
  • #457
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No, it isn't. It has nothing to do with religion. Your posts are way out of line.
Enough derailing. We'll agree to disagree. Thanks
 
  • #458
stevendaryl
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CLAIMING that something unprovable that directly disagrees with observation IS TRUE is indeed the definition of 'borderline religious'
Your description of what he was doing is false and insulting, and your claim about the definition of "religious" is false.
 
  • #459
stevendaryl
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Enough derailing. We'll agree to disagree. Thanks
No, it's not about "agreeing to disagree". It's about violating the rules of Physics Forums. Your posts are not in keeping with the principles of civility.
 
  • #460
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So far there is pretty much no agreement amongst even supporters of MWI in terms of how to solve preferred basis problem and Born Rule problem. Yougot no solution either. You sounds borderline religious with this dogmatic "WE ARE"
Well its generally accepted decoherence solves the preferred basis problem as standard textbooks like the following explain:
https://www.amazon.com/dp/3540357734/?tag=pfamazon01-20&tag=pfamazon01-20

There is debate if the decision theory argument does prove the Born Rule. Now if you believe it doesn't can you explain why a rational agent would choose one that is basis dependant which is the only way Born would not be true? You would need to violate the non-contextuality theorem on page 475 of Wallaces text.

Thanks
Bill
 
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  • #461
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No, it's not about "agreeing to disagree". It's about violating the rules of Physics Forums. Your posts are not in keeping with the principles of civility.
Again I disagree. I did not attack him in any shape, way or form. He did on the other hand by categorizing everyone that disagrees with him as silly.
I also told you that we should just agree to being in disagreement and not derail the thread. For some reason this was impossible for you. Please stop spamming your disagreement. That is against the rules of PF.

ALL I said was that his claims of truth without any evidence was 'borderline religious' which I stand firmly by 100%. He is claiming that something that disagrees with observation IS true without any evidence or solutions to the problems with that view. Additionally he decided to insult everyone else by calling any alternative view silly.
I also really doubt he needs you to step in and act like his big brother.
 
  • #463
stevendaryl
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What would superposition look like in Wheeler-deWitt? Each Hilbert space vector would represent a single spacetime manifold, metric and stress-energy tensor with no "meta" time dependence, i.e., the vector would not change or evolve.

If you're a psi-epistemist, then you might view MW as simply supplying the time-evolved 3D embedded view of a subset of all flat spacetime solutions in Wheeler-deWitt. In that sense, MW actually fits nicely with quantum gravity.

I'm sure MWers have considered this, so I was hoping someone here might explain it :-)
That's an interesting observation. What it suggests to me is that maybe for the universe as a whole, there is a sort of "preferred basis" in which the large-scale geometry of the universe is in some definite configuration. In the same way that decoherence effectively transforms a superposition of alternatives into a mixed state (or ensemble) of alternatives, it seems plausible that the possible alternatives for the large-scale structure of the universe would effectively be an ensemble of noninteracting possibilities.
 
  • #464
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You keep saying that it is generally accepted, but I am the only one that has posted more than 1 source that vehemetly disagrees with that.
As I have mentioned to you finding some dissenting papers on an issue does not make what they say true. Now if you actually have an objection then you should be able to give a précis of it - not links to papers - but the actual argument in your own words. So far all I see is the factorisation issue - which is an issue - but not everyone agrees its a fatal one. The reason being, for example as I suggested, QM may have some kind of natural process such as vacuum fluctuations that defines an external environment.

Also, decoherence itself is dependent on a solution to the Born Rule issue.
Your reason for saying that is? Not a link, but your actual reason. I have posted that Wallace, in chapter 3, explains how decohorence is defined without reference to the Born Rule. Its the same as Consistent Histories - its defined in terms of the concept of history. Again it is wise before criticising something you should try to understand it.

Thanks
Bill
 
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  • #465
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