Re: Computational complexity of "running" the multiverse

From: Hal Finney <hal.domain.name.hidden>
Date: Sat, 17 Jan 2004 16:58:07 -0800

Eric Hawthorne writes:
> One of the issues is the computational complexity of "running all the
> possible i.e. definable programs" to
> create an informational multiverse out of which consistent, metric,
> regular, observable info-universes
> emerge. If computation takes energy (as it undeniably does WITHIN our
> universe), then an unfathomably
> impossibly large amount of "extra-universal" energy would be required to
> compute all info-universes.

This is an interesting posting, and I'll try to write more about it later.
I do have one objection, which is that computation actually does not
take energy within our universe. Reversible computing is a model for
doing computation with arbitrarily small amounts of energy.

Now, I'm not sure whether that actually makes a difference in the
plausibility of an abstract computational engine grinding away on all
programs simultaneously and creating all possible universes. I don't
think anyone intends this to be taken literally enough that we should
worry about where the energy, matter, time and space come from which
such a computer might need. Whether computation inherently uses energy
or not may doesn't seem that relevant.

Hal Finney
Received on Sat Jan 17 2004 - 19:59:36 PST