Deliberation as Interactive Reasoning

Most formal models of deliberative democracy posit actors who want to guide a collective choice. This assumption stands in stark contrast to deliberative democratic theory as it was originally developed. The baseline non-formal model of this theory is the ideal speech situation, in which actors aim to understand and be understood, rather than to manipulate the outcome (Cohen 1989, Habermas 1990). Actors in this model are principally interested in the reasons each has for embracing a particular alternative. Deliberation is cast as a group hunt for sound, consensus rationales rather than as a game of strategic information transmission. We present and analyze a formal model of the ideal speech situation. Each actor is endowed with a set of inferences that she uses to guide her reasoning. During deliberation, actors can make assertions and disavow previous claims, query each other for reasons and challenge statements they disagree with. The goal is to reach consensus on a rationale for making a collective choice on the problem at hand given a limited amount of time. Using this baseline model, we characterize how deliberation changes with the composition of the deliberative body. ∗Assistant Professor, Department of Political Science, 2137 Derby Hall, Ohio State University, Columbus, OH 43210 Phone: 614-247-7017, Email: [email protected] †Assistant Professor, Department of Political Science, 2114 Derby Hall, Ohio State University, Columbus, OH 43210 Phone: 614-292-7839, Email: [email protected] ‡Assistant Professor, Department of Political Science, 541 Bellamy Building, Florida State University, Tallahassee, FL 32306 Phone: 850-945-0083, Email: [email protected] Many deliberative democrats think formal theory has little to offer in the analysis of deliberative phenomena. The main reason is that existing formal theories are based on an entirely different set of motivations than the ones deliberativists emphasize in their conceptions of the practice. For example, game theory is fundamentally the study of strategic interaction, whereas deliberation presumes that participants place at least some limits on responding to their own, private incentives. Indeed, in idealized cases, the focus is instead on seeking to understand and mutually accommodate each other via public and transparent discussion. Consequently, no matter how clearly game-theoretic depictions of political talk are rendered, many deliberative democrats believe there is not all that much to be gained by engaging a formal theory that can take no account of this difference. Game theoretic models might illuminate the limiting cases of deliberative failure, or augment our understanding of the “post-talk” phase of some deliberative practices. But they cannot shed much light on the core phenomena because conceiving of public reasoning in purely instrumental terms simply misses the heart of deliberation. Formal theorists, for their part, argue that deliberativists present the veneer of wellgrounded theory without fully warranting their claims or sufficiently accounting for incentives. The practice of writing down and analyzing a formal model forces one to answer hidden questions and explore unforeseen implications. For example, even though incentives play only a limited role in deliberative theory, systematically accounting for how and why participants would want to communicate might lead to counterintuitive conclusions. In short, there has been little productive interaction between these two fields, at least as would be recognized by scholars from the other side. This impasse is lamentable but not inevitable. Non-cooperative game theory is not the only kind of formal theory. Many deliberativists recognize a role for social choice theory to supplement deliberative procedures. Habermas (1990), Cohen (1997), and others offer what even formal theorists would recognize as proto-formal theories, with readily identifiable actors and choices, albeit with unfamiliar and heretofore unformalized motivations. Staying close to