Re: Possible Worlds, Logic, and MWI

From: Wei Dai <>
Date: Mon, 13 Jan 2003 17:33:42 -0500

On Fri, Jan 10, 2003 at 08:54:38PM -0800, Tim May wrote:
> But in this, the only universe I will ever, ever have contact with, I
> optimize as best I can. And I assume all the myriad mes are doing the
> same in their universes, forever disconnected from mine.

You're taking the question too personally. The issue here is whether
rationality only involves local optimization within the branch that one is
in without regard to other branches, or whether one can also take into
account what one believes to be happening in other branches. You yourself
may be a local optimizer, but the larger question is whether rationality
allows global optimization or not. Notice that the latter is more
general than the former, because all local optimizers can be modeled as
global optimizers with a special form of utility function.

My point is that since there doesn't seem to be a reason to disallow
global optimization, it shouldn't be ruled out. I'm interested in
a decision theory that allows global optimization and want to know its
practical and philosophical consequences.

On the question of QS, I think all QS'ers can also be modeled as global
optimizers with a special form of utility function. From this perspective,
the disagreement between QS'ers and local optimizers like Tim can be seen
as a difference of opinion on what kind of utility function one should
have. (Personally I'm not convinced by either side and I'm not sure how to
answer the question myself.) Do you find this perspective useful?
Received on Mon Jan 13 2003 - 17:35:56 PST

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