Re: Parallel Universes

From: Charles Hixson (charleshixsn@earthlink.net)
Date: Tue Feb 11 2003 - 10:25:40 MST

  • Next message: Ramez Naam: "RE: Parallel Universes"

    Max M wrote:

    > ...
    > It is not like "Yesterday" is turned into "Jailhouse Rock" some of the
    > times. Yesterday remains yesterday, more or less distorted by the noise.
    >
    > It seems to me that quantum uncertainty is the noisefloor of reality.
    > There may be an infinite number of universes at the quantum level, but
    > they are nothing more than a little embedded noise in the macroscopic
    > reality.

    This may well be correct. But just try to prove it. To prove it you
    need to be able to put limits on the "noise" that may possibly occur.
    With current theories, the larger the noise pulse required, the less
    probable the transition, but there doesn't seem any obvious way to stick
    an absolute limit on the potential size of the transition.

    In particular, certain circumstances allow quantum fluctuations to
    cascade to the macroscopic level (geiger counters and bubble chambers,
    to pick two obvious examples). So a random change at the quantum level
    results in an observable change at the macroscopic level. Clearly if
    there are parallel universes, this kind of change would result in a
    universe where someone either did or didnot publish a paper. This could
    lead various people to differing conclusions, resulting in different
    actions. Etc.

    There is no obvious way to limit the differences. Depending on the
    paper, it could have resulted in, during WWII, the US not persuing the
    atomic bomb project. (That was a rather close call in this universe,
    and I think that everyone would agree that it had a rather dramatic
    effect at the macroscopic level.)

    So if there are parallel universes, then they will usually stay closely
    similar, but on rare occasions one will make an improbable transition,
    or rather a transition in an improbably environment, that will lead to a
    cascade of changes such that the two resultant universes would
    observably different at the macroscopic level. And I think that a good
    argument could be made that such transitions are rare. But this is
    quite different from saying that they don't happen. (It's
    interesting... I began this with a model of a continuum of universe
    states, and have ended up much closer to the sheaves of similar
    universes that are a stape of parallel worlds in science fiction.)

    Also remember how evolution works. It's small changes piled on small
    changes compounded over time. What isn't obvious on our scale may be
    important on another. Who knows how dependant the firing of synapses is
    to the noise lever? This would be a very effective way of achieving
    macroscopically different universes with no visible sign for the cause
    of the divergence. Again, this would be a random process, with firing
    being either enhanced or discourages in a random manner. But this
    process would lead even closely adjacent universes to diverge quickly
    at the observable level.

    A question might exist as to whether or not this differentiation is
    instantaneous, propagates at the speed of light, or perhaps propagates
    at the speed of Wigner's paradox ... i.e., only with the transmission of
    information. OTOH, this may not be a meaningful question. It's not
    clear that it's possible, even in principle, to distinguish between
    these variants. Which is, itself, the major argument against the
    multi-worlds hypothesis. There's no obvious way to test it! I once
    tried to model gravity as a force that operated in 4 dimensions through
    the adjacent parallel universes. I eventually concluded that a) the
    definition of distance was quite peculiar and b) it didn't buy me
    anything. Quantuum fluctuation is only going to affect gravity if it
    causes the government to get ready so that it shoots away the asteroid
    that would otherwise crash into the planet and either significantly
    change it's orbit or some such. In that case, those on the surviving
    side could check their gravitational constants to see if there were any
    change, but barring some such event as that, the hypothesis appears
    unverifyable.



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