Utilitarian Aggregation of Beliefs and Tastes
将Harsanyi的功利主义从冯·诺伊曼-摩根斯坦期望效用理论扩展到Savage的主观概率框架,证明帕累托条件可导出功利主义加总,并指出基于矛盾信念的一致选择不应被社会强制接受。
Fifty years ago, Harsanyi published the first of his seminal two papers on utilitarianism. His results were derived within the von Neumann Morgenstern expected utility theory. A year later, Savage incorporated subjective probability into expected utility theory in his famous book. In this note we extend Harsanyi’s utilitarianism to Savage’s framework. We show that a Pareto condition implies utilitarian aggregation: both society’s utility function and its probability measure are linear combinations of those of the individuals. This conclusion contrasts the impossibility of reconciling a Pareto condition and linear aggregation of beliefs and tastes, that was noted by several authors. We argue that the indiscriminate Pareto condition considered by these authors is not compelling. Society should not necessarily endorse a unanimous choice when it is based on contradictory beliefs. Restricting the Pareto condition to choices that only involve identical beliefs allows the extension of Harsanyi’s result to Savage’s framework.