Evaluation of an Act

The expected-utility principle asserts that an act’s utility equals its expected utility, that is, a probability-weighted average of the utilities of the act’s possible outcomes. The mean-risk principle asserts that an act’s utility equals the sum of (1) the act’s expected utility ignoring the act’s risk and (2) the intrinsic utility of the act’s risk. The justification of both principles uses the independence of evaluations of risks and prospects, taking them in isolation. The scope of intrinsic evaluations of risks and prospects makes the evaluations independent, and their independence grounds the additivity of evaluations of an act’s risks and prospects, and also the additivity of an evaluation of the act’s risk, in the sense of its exposure to chance, and the act’s evaluation ignoring its risk.