Re: poly: Infinite calculations in an open universe?

From: Tim May <>
Date: Tue Dec 09 1997 - 19:25:36 PST

At 1:59 PM -0700 12/9/97, Perry E. Metzger wrote:
>Robin Hanson writes:
>> The search result is more solid, with tight upper and lower bounds.
>> And search seems to me more applicable to Tipler's goal of simulating
>> all past possible lives.
>Am I the only person around here who feels like they aren't at all
>sure they believe the "infinite amounts of computation lets you
>simulate everything" notion? The reasoning feels as specious as Zeno's
>paradox in a lot of ways to me.

I fully agree with Perry.

It reminds me of the beliefs associated with Laplace and Lagrange that
"with enough calculation, the future of the universe and everything in it
can be known."

Even before chaos theory, we knew that calculations and trajectories "blow
up" so quickly that even simple systems cannot be modelled very far into
the future. And one doesn't have to look to "complex systems" of social or
biological agents to see this.

A billiard table with balls scattering around is a fine example. If the
positions and velocities of N balls are known to some high precision, say,
the best we can do with optical interferometers, calculations diverge
("become chaotic" in modern parlance, though without the period-doubling
aspects necessarily) in fairly short order. Even if the positions were to
be known to subatomic dimensions, the time to "divergence" would just be
moved out a fairly small number of factors.

(Many call this "chaos"...but I think of it as the result of the physical
world being built on the real number system, not the finite expansions we
are able to measure and compute with. Steve Smale of Berkeley did some
interesting work on what a Turing machine which could operate on reals
could do....I'm not saying the Universe is in fact such a machine, though I
wouldn't be surprised if someone writes a New Age Technoreligion book using
this as a thesis, sort of like what Penrose did to support his "the brain
is a mystical quantum-mechanical device" theory. And what Tipler did to
support his "The Christians were right all along and the God Computer will
resurrect the righteous at the Eschaton!!!" nonsense.)

Lots of calculations blow up at exponential rates. The arguments that
enough computons will be available to handle these exponential blow-ups is
not plausible to me.

At least not to "simulate everything." (Using just the billiard ball model,
and similar very simple, very finite models, we can quickly create
situations where the entire universe is consumed in calculations...and
that's just the baseline.)

Now it may be argued that the God Computer, or the "Eschaton Inside"
computer, doesn't "have" to simulate everything....I recall this was the
gist of discussions several years ago on the Extropians list. But this begs
the question of what such a simulation means, espeically for the True
Believers who are counting on this as their personal resurrection, their
chance at immortality, their Oneness with She or He Who is the Eschaton.
Kind of dashes their hopes when the resurrected simulations are just
Anyway, I'll try not to make any more derogatory comments about Tipler's
book. Suffice it to say I find it unconvincing. I certainly can't get too
excited about Tipler's worrying about whether the God Computer will
resinstantiate people who have been "bad."

(Why the hell, by the way, would a computer with massive computational
capabilities give one whit about resurrecting and "rerunning" the life of
some stoned hippie who died in 1969 or some neolithic hunter crushed by a
mammoth? Or any of the other tens of billions of dead corpses? Tipler
rhapsodizes about God's everlasting love for His Creations as the reason.
Give me a break.)

(And where does this information needed to "resurrect" these personalities
come from? From photons scattering into the distant billions of years off
future? Remember that billiard table? And what of the Uncertainty
Principle? And so on. Arghhhh.)

What amazes me is how on two different lists I've been on, this fascination
with Transcendance at the Eschaton Level, and not just mundane living for a
few hundred extra years, is so prevalent.


--Tim May

The Feds have shown their hand: they want a ban on domestic cryptography
Timothy C. May | Crypto Anarchy: encryption, digital money,
ComSec 3DES: 408-728-0152 | anonymous networks, digital pseudonyms, zero
W.A.S.T.E.: Corralitos, CA | knowledge, reputations, information markets,
Higher Power: 2^2,976,221 | black markets, collapse of governments.
"National borders aren't even speed bumps on the information superhighway."
Received on Wed Dec 10 04:15:20 1997

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