Justifying deliberative democracy: Are two heads always wiser than one?

Democracy is usually justified either on intrinsic or instrumental, particularly epistemic, grounds. Intrinsic justifications stress the values inherent in the democratic process itself, whereas epistemic ones stress that it results in good outcomes. This article examines whether epistemic justifications for deliberative democracy are superior to intrinsic ones. The Condorcet jury theorem is the most common epistemic justification of democracy. I argue that it is not appropriate for deliberative democracy. Yet deliberative democrats often explicitly state that the process will favour the best argument. This can only be the case if deliberation improves the overall competence of the group and of the individuals that constitute it. I analyse when deliberation will increase competences and when it will not do so and find that individual competences will not reliably increase as a result of deliberation. In order for deliberative democracy to be epistemically more effective than representative democracy, strong procedural assumptions need to be made and deliberative democracy needs to be justified based on a combination of epistemic and intrinsic elements.