Aggregation Problems and Models: What Comes First?

Abstract

The aggregation of consistent individual judgments on logically interconnected propositions into a collective judgment on the same propositions has recently drawn attention in law, philosophy, economics and computer science. Despite the apparent simplicity of the problem, reasonable aggregation procedures, such as propositionwise majority voting, cannot ensure a consistent collective outcome. The literature on judgment aggregation has been influenced by earlier work in social choice theory. As preference aggregation investigated in social choice theory, judgment aggregation studies aggregation functions under specific conditions. These are derived from properties of the preference aggregation realm. In this paper we argue that judgment aggregation problems are intrinsically different from preference aggregation ones. Thus, imposing exogenous models and properties is detrimental to a deep understanding of the specificity of judgment aggregation.