On Thu, 18 Apr 2002, Wei Dai wrote:
> On Wed, Apr 17, 2002 at 08:36:29PM -0700, H J Ruhl wrote:
> > I am interested because currently I find it impossible to support the
> > concept of a decision.
>
> I was also having the problem of figuring out how to make sense of the
> concept of a decision. My current philosophy is that you can have
> preferences about what happens in a number of universes, where each
> universe is defined by a complete mathematical description (for example an
> algorithm with no inputs for computing that universe). So you could say "I
> wish this event would occur in the universe computed by algorithm A, and
> that event would occur in the universe computed by algorithm B." Whether
> or not those events actually do occur is mathematically determined, but if
> you are inside those universes, parts of their histories computationally
> or logically depend on your actions. In that case you're in principle

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Why are you in principle unable to compute your own choices? Do you refer
to unable to predict or unable to enumerate or both? And do you mean with
certainity or only probabilistically - It seems you can compute (in both
senses) your choices probabilitically. Are you assuming that the
algorithm describing the universe in deterministic or do you allow that it
might have a random number generator?
Brent Meeker
> unable to compute your own choices from the description of the universe,
> and you also can't compute any events that depend on your choices. That
> leaves you free to say "If I do X the following will occur in universes A
> and B" even if it is actually mathematically impossible for you to do X in
> universes A and B. You can then make whatever choice best satisfies your
> preferences. Decision theory is then about how to determine which choice
> is best.
Brent Meeker
Microsoft has done for software what McDonalds has done for the
hamburger.