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Before there were observers?

  1. Nov 30, 2009 #1

    NWO

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    Q- If only conscious beings can be observers, and by the act of observation we bring particles into position and create the reality as we go along. also only this act can make the mutliple outcomes come to fruition, then what happened to the universe before there were observers to create the solid world we call reality. PLEASE HELP?:confused:
     
    Last edited by a moderator: Dec 2, 2009
  2. jcsd
  3. Nov 30, 2009 #2
    NWO, it is just a weakness of the Copenhagen Interpretation.
    There are many other interpretations of QM, and many of them does not require the "collapse" at all.
     
  4. Dec 1, 2009 #3
    There is no need of an conscious beeing for oberservation (obersvation in the QM - copenhagen sense), what the weakness of the copenhagen interpretation is though is that it requires classical apparatus - not QM apparatus.
     
  5. Dec 1, 2009 #4
    ansqar, there are different flavors of CI:
    1. observation is done by a measurement device (this has a problem with instantaneous nature collapse and the definition of 'what is a measurement device')
    2. wavefunction - is just our knowledge about the system. As wavefunction is not real, there are no problems with the collapse. But 'knowledge' requires a consciousness.

    In any case, both flavors are bad :)
     
  6. Dec 1, 2009 #5
    well CI is best for "shut up and calculate" and Bohm maybe best for interpretations
     
  7. Dec 1, 2009 #6
    no, MWI is the best :)
     
  8. Dec 1, 2009 #7
    LOL no MWI has no predictivity power and is hence not science at all ;)
     
  9. Dec 1, 2009 #8
    Why? Observationally MWI is equivalent to Bohmian
     
  10. Dec 1, 2009 #9

    Fredrik

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    Only if the wavefunction is assumed to represent all the properties of the system rather than the properties of an ensemble of identically prepared systems. Only the critics of "the CI" seem to include that assumption in the definition of the CI, so it seems to me that you guys are attacking a straw man.

    I haven't been able to make sense of that version of the CI either, but after skimming through the stuff on this page (posted by Fra in another thread), I now think that this version of the CI is just a different interpretation of probability, not a different interpretation of the physics.
     
  11. Dec 1, 2009 #10

    Fredrik

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    The MWI is just the assumption that every system including the entire universe obeys the laws of QM. You can still decompose the universe into subsystems, e.g. "you+system+environment" and use that decomposition to make the same predictions as any other interpretation.

    It's easy to think that what you just said is correct (I was saying the same thing myself a year ago) if you've been listening to the MWI proponents. They like to define it by removing the probability rule and not mentioning (or not understanding) that they're replacing it with an assumption that's essentially equivalent to the probability rule: that the Hilbert space of a system is the tensor product of the Hilbert spaces of the subsystems. See e.g. this article. His definition strongly suggests that the probability rule isn't a part of the MWI, and just a few lines later he's using the essentially equivalent assumption without stating (and maybe without realizing) that it's an assumption, and that it's a strong one.
     
    Last edited: Dec 1, 2009
  12. Dec 1, 2009 #11

    Fra

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    Here is a more tasty flavour ;)

    3. wavefunction - is just the observing systems knowledge about the system in question. As wavefunction is not observer independent, there are no inconsistencies due to the collapse. Requires no consciousness - knowledge can be thought of as the observers evolved/tuned expectation of the system in question - where this evolving expectations can be thought of as an inference process, which is driven by the flow of new information. The implications of the expectations is that it implies a prefences for the actions, in the sense that the actions are "favourable" or rational choices given the premises.

    Fredrik(user) is right that to a good extent, the interpretation of probabiltiy is a key difference in my view.

    In my view, one is lead not that quantum mechanics as it stands only makes sense as a special case, since a objectively deterministic evolution equation is not consistent with the idea that the evolution is an expected evolution. If the subjectively expectation is assumed to be correct, then the evolution is deterministic. But since the whole spirit of this version 3 of interpretation is to quantify all expectations, there is no physical basis in terms of information processing where a 100% confidence can be acheived.

    I hold a subjective bayesian view, in combination with an evolutionary perspective where only the selection comes from an equilibrium population of subjective views. So I replace the multiverse idea with the multiview idea, and then use a sort of subjective probability. The probability spaces and thus also hilbert spaces are then also evolving.

    So in this flavour, the "issues" that are obvious instead suggests that current QM is only a special case of a more general theory. So this is more than an interpretation only.

    /Fredrik
     
  13. Dec 1, 2009 #12

    Fra

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    Yes, but somehow the physical meaning of what probabilty is, is quite crucial from the point of view of understanding and extending the theory, right? Because if our theory makes predictions not on single events, but only on probabiltiy level, then the meaning of this is quite important.

    So as I've rambled in several threads in the past, my interpretations does come with suggestions on how to improve things, and this does suggest to me a different physics. (but it does not make a difference to the currently tested domains of QM of couse, it only regards some of the open questions, such as unification of forces and QG)

    /Fredrik
     
  14. Dec 1, 2009 #13

    Demystifier

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    I perfectly agree with that. Even though other interpretations also have some interpretational merits, the Bohmian one is the "best" in the sense that it is most intuitive. For example, it is very difficult, if not impossible, to understand INTUITIVELY the origin of the Born rule in MWI.
     
  15. Dec 1, 2009 #14
    1 contradicts 2

    Knowledge of system A about system B depends on A and B
    Hence systems A and Z can have different and inconsistent knowledge about system B
     
  16. Dec 1, 2009 #15

    Fra

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    Ok I see I'm forced to elaborate a little more.
    That two observers have different knowledge about B is not really a "physical inconsistency" at all. It is only an inconsistency for those who insist on a certain level of realism.

    Instead the implication (which was not clear from my past post) in my view, is that the two observers act differently against B (in consistency with their differing information).

    This instead predicts an interaction between A and Z, the result of this interaction can be thought of as a negotiation between A and Z. They both update their previous knowledge in the light of a "second opinon" :)

    So there is a great beauty here, not inconsistencies.

    This is no more inconsistent than the fact that two observes in different inertial frames measure different wavelenghts of a light source.

    The difference is that in SR, the symmetry transformation that provides a covariant description and thus recovers consistency is hardcoded. In my view, these symmetries are emergent.

    /Fredrik
     
  17. Dec 1, 2009 #16

    Fra

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    I see this overlaps to the old thread of Dmitry.

    "The role of false info in the Copenhagen Int. "
    https://www.physicsforums.com/showthread.php?t=301893

    Instead of a realist objective measure of right or wrong knowledge, there is a democracy of opinons, and the system whose prior information proves to be sort of "in contradiction" to the future evolution, will pay a price for this - it will be forced to negotiation with it's environment to revise the information, or face desctruction.

    Thus, part of regular QM is an "quasi-equilibrium version" of something even more weird.

    /Fredrik
     
  18. Dec 1, 2009 #17

    Fredrik

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    That sounds right on the surface, but in my opinion, the only interpretation that can have any value to a physicist is the frequency interpretation. Baez complains about how the limit of large n doesn't really exist in the real world, but so what? That only means that the "thing in the real world" that corresponds to an expectation value doesn't have an exact definition, but why should that matter when none of the "things in the real world" that a theory associates with a mathematical object or a mathematical structure has an exact definition? Those things are all defined operationally, so they can't possibly have an exact definition anyway.
     
  19. Dec 1, 2009 #18
    Before there were observers, there were no observables. It's a reality of nature and it's meaningless to ask for proof.
     
  20. Dec 1, 2009 #19

    Demystifier

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    But is there reality beyond the observed reality?
     
  21. Dec 1, 2009 #20
    99.999% of the 13 billion years after the Big Bang there were no intelligent beings
    So, what Cosmology is studying? :)
     
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