CS 789 THEORY SEMINAR** **[home]

NOTE: *****Time/place change: 4:10pm/498
Uris***********

Speaker:
Joseph Halpern, Cornell University

Date: November 21, 2005

Title: Redoing the
Foundations of Decision Theory: Decision Theory with Subjective States and
Outcomes\\

Abstract:

The standard approach in decision theory (going
back to Savage) is to place a preference order on acts, where an act is a
function from states to

outcomes. If the preference order satisfies appropriate postulates, then the
decision maker can be viewed as acting as if he has a probability on states and
a utility function on outcomes, and is maximizing expected utility. This
framework implicitly assumes that the decision maker knows what the states and
outcomes are. That isn't reasonable in a complex situation. For example, in
trying to decide whether or not to attack Iraq, what are the states and what are
the outcomes? We redo Savage viewing acts essentially as syntactic programs. We
don't need to assume either states or outcomes. However, among other things, we
can get representation theorems in the spirit of Savage's theorems; for Savage,
the agent's probability and utility are subjective; for us, in addition to the
probability and utility being subjective, so is the state space and the outcome
space. I discuss the benefits, both conceptual and pragmatic, of this approach.

This is joint work with Larry Blume and David Easley. No prior knowledge of
Savage's work is assumed.