Symbolic Utility and Rational Action

Standard decision theory tells us that a rational agent maximises expected utility: she assigns probabilities to outcomes, utilities to those outcomes, and chooses the action with the highest expected utility. Nozick accepts this framework as far as it goes but argues it is incomplete. It cannot explain why rational people vote when their individual vote is vanishingly unlikely to be decisive; why they keep promises when violation would go undetected; why they cooperate in one-shot prisoner's dilemma games; or why they refuse to act badly even when the expected consequences of refusal are worse than the consequences of acting badly. In each case, standard decision theory predicts defection; actual rational agents often cooperate.

Nozick introduces the concept of "decision value" to supplement expected utility. The decision value of an action includes its expected utility plus the symbolic utility of being the kind of person who performs that action in that situation. Voting, keeping promises, and cooperating have positive symbolic utility because they are the kinds of actions that express and reinforce a self-conception as a person of integrity, reciprocity, and civic virtue. The agent who votes is not just trying to influence the election; she is also performing an action that says something about who she is and that, over time, helps constitute the kind of person she wants to be.

The broader implication of Nozick's argument is that rationality includes a principled dimension that pure consequentialism misses. An agent who acts from principles — never lie, always keep promises, always cooperate when others cooperate — is not being irrational when her principles occasionally generate worse outcomes than their violation would. She is expressing and sustaining a mode of being in the world that has intrinsic value, and that produces better outcomes across the long run of social interaction by making her a credibly trustworthy partner. Rational action is action that fits both what one values and what one is.

The Nature of Rationality was delivered as a series of lectures and published in 1993. Nozick's account of symbolic utility has been compared to work by David Gauthier on constrained maximisation and by Derek Parfit on self-defeating theories of rationality.