Utility

In economics, utility is a measure of the satisfaction that a certain person has from a certain state of the world. Over time, the term has been used in two different meanings.

• The term was introduced initially as a measure of pleasure or happiness as part of the theory of utilitarianism, by moral philosophers such as Jeremy Bentham and John Stuart Mill. In this context, the utilities of different people in the same state are comparable. In particular, one can compute the sum of all peoples' utilities in each state, and choose the state in which the sum is maximized; this leads to the utilitarian rule of social choice.
• The term has been adapted and reapplied within neoclassical economics, which dominates modern economic theory, as a representation of a consumer's ordinal preferences over a choice set. In this context, utility is not comparable across different consumers or possessing a cardinal interpretation. In fact, every monotone transformation of a utility function represents the same ordinal ranking over the alternatives, and thus is equivalent from the neoclassical economics point of view. In game theory, too, utility is used in the same meaning. This concept of utility is personal and based on choice rather than on pleasure received, and so requires fewer behavioral assumptions than the original concept.