Democratic Deliberation and Social Choice: A Review
Oxford Handbook of Deliberative Democracy, Forthcoming
24 Pages Posted: 15 Jun 2017
Date Written: June 14, 2017
In normative political theory, it is widely accepted that democratic decision making cannot be reduced to voting alone, but that it requires reasoned and well-informed discussion by those involved in and/or subject to the decisions in question, under conditions of equality and respect. In short, democracy requires deliberation. In formal political theory, by contrast, the study of democracy has focused less on deliberation, and more on the aggregation of individual preferences or opinions into collective decisions – social choices – typically through voting. While the literature on deliberation has an optimistic flavour, the literature on social choice is more mixed. It is centred around several paradoxes and impossibility results showing that collective decision making cannot generally satisfy certain plausible desiderata. Any democratic aggregation rule that we use in practice seems, at best, a compromise. Initially, the two literatures were largely disconnected from each other. Since the 1990s, however, there has been a growing dialogue between them. This paper reviews the connections between the two. Deliberative democratic theory is relevant to social choice theory in that deliberation can complement aggregation and open up an escape route from some of its negative results. Social choice theory is relevant to deliberative democratic theory in that its formal models can shed light on some aspects of deliberation, such as the nature of deliberation-induced opinion change. The paper is structured as follows. First, I introduce the notions of social choice and deliberation. Next, I discuss several hypotheses on the effects of deliberation on preferences and assesses their implications for social choice. Then I review some social-choice-theoretic models of deliberation and consider the mechanisms of deliberation-induced opinion change. Finally, I address deliberation from the perspective of judgment-aggregation theory, the branch of social choice theory that focuses on the aggregation of judgments rather than preferences.
Keywords: Deliberative democracy, social choice, aggregation, deliberation, Arrow's theorem, Condorcet's paradox, possibility results, consensus, meta-consensus
JEL Classification: D70, D71
Suggested Citation: Suggested Citation