Abstract

In recent years rational decision theories such as Richard Jeffrey's, which recommend that an agent act so as to maximize his conditional expected utility, have come under attack on the grounds that they are unable to adequately handle certain kinds of decision problems. Because of their general structure, these problems are sometimes known as "causal counterexamples" to the theories; well-known examples are Newcomb's problem, the Prisoner's Dilemma, and Fisher's smoking gene problem. Several versions of "causal decision theory" have been presented by Gibbard and Harper, Brian Skyrms, and David Lewis; these theories are designed to deal with the counterexamples correctly. In this dissertation I show how an axiomatic treatment, including representation and uniqueness theorems, for Brian Skyrms' version of causal decision theory can be obtained from work done by Peter Fishburn on another theory; I partially reinterpret Fishhburn's formal theory and then show how the expected utility rule of Skyrms' theory can be derived from the rule of Fishburn's theory. With the interpretation I give of the formal theory, together with an account of conditional preference which I develop, I reply to criticisms which have been made of Skyrms' theory: It has been suggested that the theory is flawed because it requires the use of "K-partitions" of state descriptions which must be identified by judging the causal independence of the states from the possible actions and the causal relevance of the states to the problem. This is thought to be an undesirable dependence of rational decision theory upon an adequate theory of causal independence and causal relevance. I argue that this criticism is mistaken, and I state conditions which identify adequate K-partitions of state descriptions in terms of the behavior of those descriptions in the agent's prference system. Finally, I discuss the axioms of the formal theory under my interpretation of them, and I conclude that, properly understood, they are reasonable requirements for rational conditional preferences, so that the causal decision theory is well-founded.