Re: Tough questions

From: Matt Gingell (mjg223@nyu.edu)
Date: Mon Sep 06 1999 - 11:34:46 MDT


----- Original Message -----
From: david gobel <dgobel@doubled.com>
>Thus, my conclusion is that whether a world is simulated on a
>hypersupermegametacompumaniac...or a balsa wood abacus of sufficient
>complexity...it's still a real world.

It seems to me that there must be some smallest unit of matter capable of doing
computation, some sort of computational 'atom', in the ancient Greek sense of
the word. This would impose an upper bound on the amount of number crunching you
could possibly do with a finite amount of mass.

For instance, I would argue that a system of N atoms can not simulate a system
of N+1 atoms in real time with perfect fidelity. This limit holds no matter how
clever you are, no matter how efficiently you implement your simulator. If you
were able to, then your computer would be able to simulate itself, and still
have 1 atom worth of power left over. The simulated machine could in term
simulate itself, and itself have one atom of left over. This spirals down to
infinity and you'd have an infinite number of atoms left over, each of which
could be harnessed to do some small amount of work.

Therefore - if we are being simulated by a computer built in a world whose
physics match our own, and we are being simulated in real time, then the
computer simulating us must be at least as big as our entire universe.

-matt



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