Abstract

If we construe decision theory as providing a framework for a complete, instrumentalist account of practical rationality, then certain paradoxes of choice become problematic. My project shows why it seems highly unlikely that rational choice theory, which is what I call this interpretation of decision theory, will resolve a range of paradoxes. ;I focus on three sorts of constraint imposed by the theory. Preferences are to be taken as given on this conception of rationality. A related point restricts the function of reason to the determination of the optimal means to given ends: reason therefore does not evaluate ends as such. Third, the theory conceives optimality of means in terms of maximal expected utility. ;The argument proceeds by first showing why the three considerations pertaining to preference and reason are responsible for generating the paradoxes in question. Second, I argue that the three constraints are necessary for the strict instrumentalism of rational choice theory. If these two points are correct, it follows that no instrumentalist conception of rationality based on decision theory can resolve these paradoxes. ;Furthermore, the ongoing debates among versions of rational choice theory concerning the proper interpretation of the probability component of expected utility suggest that no version has achieved dominance. I argue that this situation reflects the fact that no version of the theory can capture all of the reasons available to a rational agent in the paradoxes. This result supports the conclusion that rational choice theory is essentially incomplete. ;I deploy this argument by assessing three recent attempts from the philosophical literature to resolve the paradoxes. These books--Robert Nozick's The Nature of Rationality, David Gauthier's Morals by Agreement, and S. L. Hurley's Natural Reasons--each present views of independent philosophical interest, but they concern me because they offer novel and sophisticated approaches to the paradoxes of rational choice. Each proposal fails, however, in some way predicted by the argument just given, which lends support to my general argument. This inability of rational choice theory to resolve the paradoxes points up its inadequacy as an account of practical rationality.