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From: Christopher Maloney <dude.domain.name.hidden>

Date: Fri, 30 Jul 1999 07:06:24 -0400

Russell Standish wrote:

*>
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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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*>
*

This is from Tegmark's paper (although I think he was paraphrasing

Tipler from Physics of Immortality):

Let us imagine a hypothetical Universe much larger than our own,

which contains a computer so powerful that it can simulate the time-

evolution of our entire Universe. By hypothesis, the humans in this

simulated world would perceive their world as being as real as we

perceive ours, so by definition, the simulated universe would have

PE [physical existence]. Technical objections such as an infinite

quantity of information being required to store the data appear to

be irrelevant to the philosophical point that we will make. For

instance, there is nothing about the physics we know today that

suggests that the Universe could not be replaced by a discrete and

finite model that approximated it so closely that we, its

inhabitants, could not tell the difference. That a vast amount of

CPU-time would be needed is irrelevant, since that time bears no

relation to the subjective time that the inhabitants of the Universe

would perceive. In fact, since we can choose to picture our Universe

not as a 3D world where things happen, but as a 4D world that merely

is, there is no need for the computer to compute anything at all --

it could simply store all the 4D data, and the "simulated" world

would still have PE. Clearly the way in which the data is stored

should not matter, so the amount of PE we attribute to the stored

Universe should be invariant under data compression. The physical

laws provide a great means of data compression, since they make it

sufficient to store the initial data at some time together with the

equations and an integration routine. In fact, this should suffice

even if the computer lacks the CPU power and memory required to

perform the decompression. The initial data might be simple as well,

containing so little algorithmic information that a single CD-ROM

would suffice to store it. After all, all that needs to be stored

is a description of the mathematical structure that is isomorphic to

the simulated universe. Now the ultimate question forces itself

upon us: for this Universe to have PE, is the CD-ROM really needed

at all? If this magic CD-ROM could be contained within the simulated

Universe itself, then it would "recursively" support its own PE.

This would not involve any catch-22 "hen-and-egg" problem regarding

whether the CD-ROM or the Universe existed first, since the Universe

is a 4D structure which just is ("creation" is of course only a

meaningul notion within a spacetime). In summary, a mathemtaical

structure with SASs would have PE if it could be described purely

formally (to a computer, say) -- and this is of course little else

than having mathematical existence.

Date: Fri, 30 Jul 1999 07:06:24 -0400

Russell Standish wrote:

This is from Tegmark's paper (although I think he was paraphrasing

Tipler from Physics of Immortality):

Let us imagine a hypothetical Universe much larger than our own,

which contains a computer so powerful that it can simulate the time-

evolution of our entire Universe. By hypothesis, the humans in this

simulated world would perceive their world as being as real as we

perceive ours, so by definition, the simulated universe would have

PE [physical existence]. Technical objections such as an infinite

quantity of information being required to store the data appear to

be irrelevant to the philosophical point that we will make. For

instance, there is nothing about the physics we know today that

suggests that the Universe could not be replaced by a discrete and

finite model that approximated it so closely that we, its

inhabitants, could not tell the difference. That a vast amount of

CPU-time would be needed is irrelevant, since that time bears no

relation to the subjective time that the inhabitants of the Universe

would perceive. In fact, since we can choose to picture our Universe

not as a 3D world where things happen, but as a 4D world that merely

is, there is no need for the computer to compute anything at all --

it could simply store all the 4D data, and the "simulated" world

would still have PE. Clearly the way in which the data is stored

should not matter, so the amount of PE we attribute to the stored

Universe should be invariant under data compression. The physical

laws provide a great means of data compression, since they make it

sufficient to store the initial data at some time together with the

equations and an integration routine. In fact, this should suffice

even if the computer lacks the CPU power and memory required to

perform the decompression. The initial data might be simple as well,

containing so little algorithmic information that a single CD-ROM

would suffice to store it. After all, all that needs to be stored

is a description of the mathematical structure that is isomorphic to

the simulated universe. Now the ultimate question forces itself

upon us: for this Universe to have PE, is the CD-ROM really needed

at all? If this magic CD-ROM could be contained within the simulated

Universe itself, then it would "recursively" support its own PE.

This would not involve any catch-22 "hen-and-egg" problem regarding

whether the CD-ROM or the Universe existed first, since the Universe

is a 4D structure which just is ("creation" is of course only a

meaningul notion within a spacetime). In summary, a mathemtaical

structure with SASs would have PE if it could be described purely

formally (to a computer, say) -- and this is of course little else

than having mathematical existence.

-- Chris Maloney http://www.chrismaloney.com "Donuts are so sweet and tasty." -- Homer SimpsonReceived on Fri Jul 30 1999 - 04:15:49 PDT

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