Public Reason, Social Choice, and Cooperation*

Economic theory and legal theory can both claim to provide plausible accounts of rational decision-making. Yet, despite the growth of "law and economics" as a hugely successful area of interdisciplinary study, therff is very little intellectual exchange between the rational choice theorist who attempts to explain economic behaviour on the one hand, and the more philosophically inclined theorist who seeks to comprehend legal reasoning and adjudication on the other. Thus, the claim that each sort of theorist makes to account for rational decision-making seems largely to go unanswered by the other, this despite the fact that the two disciplines are otherwise so interconnected. While the two sorts of theory loosely understand the rationality of a set of decisions in the same way, namely as an "ordered particularity", the notion of ordering is fundamentally different between the two. In economics, no matter how diverse the motivations for choice might appear to be, the idea of an ordering remains somewhat single-minded and "quantitative", the sort of thing over which a chooser can maximize. Thus, in social choice theory, for example, the idea persists that the plurality of ordefings (of either individuals or choice criteria) that are the inputs into the social choice function are to be reduced to, or reconciled into, the lineafity of an "all things considered" social ordering of the alternatives available for choice. But in law the notion of an ordering is less quantitative and more "categorical", the sort of thing that informs an understanding. We make sense of the many particular decisions that we observe in the legal world by rendering them coherent with one another under the aspect of general concepts and rules of thought that are accessible to shared reasons and amenable to public justification. One of the challenges for those who do research on rational decision-making is to comprehend the intellectual difference between these two accounts of rationality in a way that makes each accessible to the other, that is, that puts them within some common theoretical framework