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From: Higgo James <james.higgo.domain.name.hidden>

Date: Fri, 30 Jul 1999 12:19:58 +0100

Right, so 'Let a=a+1 goto start" is a mathematical structure with SASs.

That's how far we can compress an MWI universe. But you cannot compress a

single classical universe.

*> -----Original Message-----
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*> From: Christopher Maloney [SMTP:dude.domain.name.hidden]
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*> Sent: Friday, July 30, 1999 12:06 PM
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*> To: everything-list
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*> Subject: Re: Fwd: Implementation/Relativity
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*>
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*>
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*>
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*> Russell Standish wrote:
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*> >
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*> > Not every position, momentum etc of particles are relevant to the
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*> > existence of ouselves as SASes. However, other properties, are, such
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*> > as the value of the fine structure constant. To describe a universe
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*> > which gives rise to human-like conscious being probably does not
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*> > require very much information - the axioms of quantum mechanics,
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*> > axioms of probability theory, the values of a few fundamental
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*> > quantities etc. etc. In all probability, the universe could be
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*> > described by something fitting on a conventional floppy disk. However,
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*> > the program required to expand this description could not be executed
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*> > within our universe, for reasonably obvious reasons.
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*> >
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*>
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*> This is from Tegmark's paper (although I think he was paraphrasing
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*> Tipler from Physics of Immortality):
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*>
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*> Let us imagine a hypothetical Universe much larger than our own,
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*> which contains a computer so powerful that it can simulate the time-
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*> evolution of our entire Universe. By hypothesis, the humans in this
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*> simulated world would perceive their world as being as real as we
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*> perceive ours, so by definition, the simulated universe would have
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*> PE [physical existence]. Technical objections such as an infinite
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*> quantity of information being required to store the data appear to
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*> be irrelevant to the philosophical point that we will make. For
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*> instance, there is nothing about the physics we know today that
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*> suggests that the Universe could not be replaced by a discrete and
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*> finite model that approximated it so closely that we, its
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*> inhabitants, could not tell the difference. That a vast amount of
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*> CPU-time would be needed is irrelevant, since that time bears no
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*> relation to the subjective time that the inhabitants of the Universe
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*> would perceive. In fact, since we can choose to picture our Universe
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*> not as a 3D world where things happen, but as a 4D world that merely
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*> is, there is no need for the computer to compute anything at all --
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*> it could simply store all the 4D data, and the "simulated" world
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*> would still have PE. Clearly the way in which the data is stored
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*> should not matter, so the amount of PE we attribute to the stored
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*> Universe should be invariant under data compression. The physical
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*> laws provide a great means of data compression, since they make it
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*> sufficient to store the initial data at some time together with the
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*> equations and an integration routine. In fact, this should suffice
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*> even if the computer lacks the CPU power and memory required to
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*> perform the decompression. The initial data might be simple as well,
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*> containing so little algorithmic information that a single CD-ROM
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*> would suffice to store it. After all, all that needs to be stored
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*> is a description of the mathematical structure that is isomorphic to
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*> the simulated universe. Now the ultimate question forces itself
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*> upon us: for this Universe to have PE, is the CD-ROM really needed
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*> at all? If this magic CD-ROM could be contained within the simulated
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*> Universe itself, then it would "recursively" support its own PE.
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*> This would not involve any catch-22 "hen-and-egg" problem regarding
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*> whether the CD-ROM or the Universe existed first, since the Universe
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*> is a 4D structure which just is ("creation" is of course only a
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*> meaningul notion within a spacetime). In summary, a mathemtaical
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*> structure with SASs would have PE if it could be described purely
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*> formally (to a computer, say) -- and this is of course little else
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*> than having mathematical existence.
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*>
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*>
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*>
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*> --
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*> Chris Maloney
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*> http://www.chrismaloney.com
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*>
*

*> "Donuts are so sweet and tasty."
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*> -- Homer Simpson
*

Received on Fri Jul 30 1999 - 04:23:17 PDT

Date: Fri, 30 Jul 1999 12:19:58 +0100

Right, so 'Let a=a+1 goto start" is a mathematical structure with SASs.

That's how far we can compress an MWI universe. But you cannot compress a

single classical universe.

Received on Fri Jul 30 1999 - 04:23:17 PDT

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