Re: Possible Worlds, Logic, and MWI

From: Wei Dai <weidai.domain.name.hidden>
Date: Mon, 13 Jan 2003 20:31:35 -0500

Continuing with my last post...

On Fri, Jan 10, 2003 at 08:54:38PM -0800, Tim May wrote:
> Why would there be any reason to try to maximize the utility of this
> "big picture"?
>
> For those of us who don't even strive for "the greatest good for the
> greatest number" in a single-branch universe, why would striving for
> more good (whatever "good" is) in 10^300+ branches be interesting or
> important?

Consider a thought experiment where you've been uploaded into a
multi-tasking computer and there are 100 copies of you running in parallel
in separate virtual environments. Would you prefer that all 100 copies of
you experience the exact same things, or that they experience different
things? I think running the same computation 100 times is pointless, so
I'd prefer the latter. This seems to be essentially analogous to prefering
variety across branches in MWI. Even if you disagree personally with these
choices, do you have any reason to think that they are irrational, rather
than just different? If they're not irrational, then decision theory has
to be able to handle them, and that has interesting consequences.

> In any case, if MWI is correct, then there is every type of universe
> imaginable, consistent only with the laws of physics and math, and
> every decision for the good or the bad or whatever has been made
> countless times in countless ways. By any calculus of the multiverse,
> the sheaf of universes in which Tim May or Hal Finney even exist is of
> measure approaching zero.
>
> Meanwhile, I'm _here_.

I'm not sure what your point is here. You may be saying that the
multiverse is so big, and the part of it that we can affect is so small,
that if you try to optimize the "big picture" the difference you can make
is almost undetectable on a human scale. If so, I agree -- it's a very
alien way of thinking, but that doesn't mean it's wrong.
Received on Mon Jan 13 2003 - 20:33:07 PST