Editing Social welfare function (section)

=== Harsanyi's theorem ===
Introducing one additional axiom—the nonexistence of [[Coherence (philosophical gambling strategy)|Dutch Books]], or equivalently that social choice behaves according to the [[Von Neumann–Morgenstern utility theorem|axioms of rational choice]]—implies that the social choice function must be the [[utilitarian rule]], i.e. the weighting function <math>w(u)</math> must be equal to the utility functions of each individual. This result is known as [[Harsanyi's utilitarian theorem]].