Abstract

Morality is concerned with interaction among persons, and so with strategic choice, in which each adopts a strategy on the basis of what he expects others to do. We state three conditions of strategically rational choice, and show that on the maximizing conception of rationality they require the expected outcome of interaction to be in equilibrium, so that each person's choice is a maximizing response to the choices of the others. We mention Nash's proof that in any finite situation, there is at least one set of equilibrium strategies, but we then introduce the well‐known result, exemplified by the Prisoner's Dilemma, that, in many situations, no set of equilibrium strategies achieves optimality. In such situations, everyone could benefit were they to interact, not on the basis of individual utility maximization, but on a basis that would yield an optimal outcome.