On Thu, 18 Apr 2002, Wei Dai wrote: > On Thu, Apr 18, 2002 at 12:26:21PM -0700, Brent Meeker wrote: > > Perhaps "contradictory" is too strong a word - I should have stuck with > > "incoherent". But it seems you contemplate having different wishes about > > the future evolution of the world and you want to find some decision > > theory that tells you what action to take in order to maximize desirable > > outcomes. But if the world is already determined, then so are you actions > > and your decision processes. Thus are actions and decision processes are > > supposed to be determined in two completely different ways - one at the > > level of physical processes of the universe, the other at the level of > > desires and decision theory. These two are not necessarily contradictory, > > but to avoid contradiction you need to add the constraint on the decision > > theory you follow that it agree with what your actions are as defined by > > the mathematical description of the universe. > > While you're contemplating a decision, you have no way, even in principle, > of determining the action that agrees with the mathematical > description of the universe. Therefore as a normative matter, adding "the > constraint on the decision theory you follow that it agree with what your > actions are as defined by the mathematical description of the universe" > doesn't do anything.

Exactly. So what does the assumption about the complete mathematical description add? > As a positive theory, decision theory is going to be wrong sometimes (e.g. > not predict what people actually do), but it may be able to make up for > that with conceptual elegance and simplicity. Hmm. Maybe I misunderstood your objective. I thought it was to decide what action to take - not to predict what some person will do. Brent Meeker "Imagine the Creator as a low comedian, and at once the world becomes explicable." -- HL Mencken