On Tue, Sep 27, 2011 at 11:52 PM, meekerdb <[email protected]> wrote:
> On 9/27/2011 9:13 PM, Jason Resch wrote: > > >> I don't think that. I just noted it's logically possible, contrary to >> assertions that our universe must be duplicated infinitely many times. > > > If our universe is not duplicated a huge number of times, then quantum > computers would not work. They rely on huge numbers of universes different > from ours aside from a few entangled particles. Even normal interference > patterns are explained by there existing a huge number of very similar > universes. > > > Or by Feynmann paths that zigzag in spacetime. Don't become to enamored of > an interpretation. > > If you assume there is a single photon interfering with itself, how is it that this one particle can evaluate a problem whose computational complexity would exceed that of any conventional computer using all the matter in the universe? > > > >> >> >> However, according to Vilenkin, Greene, and >>> Tegmark, a generic prediction of the theory of inflation is that there >>> is an *infinite* number of Hubble volumes (what you are calling >>> universes). Let's call the hypothesis that all quantum-physical >>> possibilities are realized infinitely many times "the hypothesis of >>> Cosmic Repetition". Brian Greene argues for this hypothesis quite >>> persuasively. He says, "In an infinitely big universe, there are >>> infinitely many patches [i.e., Hubble volumes]; so, with only finitely >>> many different particles arrangements, the arrangements of particles >>> within patches must be duplicated an infinite number of times." (The >>> Hidden Reality, pg. 33) >>> >> It's plausible - but not logically required. Suppose all the infinite >> universes are number 1, 2, ... Number 1 is ours. Number 2 something >> different. Numbers 3,4, ...inf are exact copies of number 2. So there are >> only two arrangements of particles; in spite of there being infinitely many >> universes. > > > Not logically required, but I would say it is not consistent with our > current theories and observations. > > >> >> >> >>> As for the probability distribution of matter and/or outcomes, I'll >>> let Tegmark do the explaining: >>> >>> "Observers living in parallel universes at Level I observe the exact >>> same laws of physics as we do, but with different initial conditions >>> than those in our Hubble volume. >>> >> >> This is questionable. Most theories of the universe starting from a >> quantum fluctuation or tunneling from a prior universe assume that the >> universe must start very small - no more than a few Planck volumes. > > > The generalized theory of inflation is eternal inflation. It leads to an > exponentially growing volume which expands forever. > > >> This limits the amount of information that can possibly be provided as >> initial conditions. So where does all the information come from? > > > I haven't heard the theory that there is an upper bound on the > information content for this universe set by the big bang. > > > In one Planck volume there is only room for one bit. That's the > holographic principle. > > Yet our universe appears to take more than 1 bit to describe, and it seems to have a possibly infinite volume. > > > As to where information comes from, if all possibilities exist, the total > information content may be zero, and the appearance of a large amount of > information is a local illusion. > > >> QM allows negative information (hidden correlations) so that one >> possibility is that the net information is zero or very small and the >> apparent information is created by the existence of the hubble horizon. >> >> >> The currently favored theory is that >>> the initial conditions (the densities and motions of different types >>> of matter early on) were created by quantum fluctuations during the >>> inflation >>> epoch (see section 3). This quantum mechanism generates initial >>> conditions that are for all practical purposes random, producing >>> density fluctuations described by what mathematicians call an ergodic >>> random field. Ergodic means that if you imagine generating an ensemble >>> of universes, each with its own random initial conditions, then the >>> probability distribution of outcomes in a given volume is identical to >>> the distribution that you get by sampling different volumes in a >>> single universe. >> >> > That's not what ergodic means. In the theory of stochastic processes it > means that ensemble statistics are the same as temporal statistics. In the > eternal expansion theory it is not assumed that the physics is the same in > each bubble universe. > This one "bubble" is infinitely big according to eternal inflation. > It is hypothesized that the spontaneous symmetry breaking that results in > different coupling constants for the weak, strong, EM, and gravity forces is > random. That's how it provides and anthropic explanation for "fine-tuning" > - we're in the one where the random symmetry breaking was favorable to life. > This is one hypothesis to explain fine tuning, I am not sure how well it is supported. > > > In other words, it means that everything that could >>> in principle have happened here did in fact happen somewhere else. >>> Inflation in fact generates all possible initial conditions >>> >> > But it's not initial conditions. It's random symmetry breaking. > > > with non-zero probability, the most likely ones being almost uniform >>> with fluctuations at the 10^5 level that are amplified by >>> gravitational clustering to form galaxies, >>> stars, planets and other structures. This means both that pretty much >>> all imaginable matter configurations occur in some Hubble volume far >>> away, and also that we should >>> expect our own Hubble volume to be a fairly typical one — at least >>> typical among those that contain observers. >> >> > But this sort of undercuts the need for the anthropic explanation. If our > universe is "typical" (i.e. probable) then there's no need to invoke > infinitely many others to avoid the "fine-tuning" problem. You could just > say it's the more probable one and so it's the one that happened. > > Brent > "If an explanation could easily explain anything in the given field, then > it actually explains nothing." > > Which explanation is this referring to? Jason -- You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. 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