 On an epistemic conception, the value of democratic institutions lies, in part, in their tendency to arrive at the truth in matters relevant to public decisions (see Estlund 2008, but compare Peter 2011). This idea receives some support from Condorcet’s jury theorem. It tells us, simply put, that if individual people are more likely than not to judge correctly in some matter of fact, independently of one another, then the collective judgment of a sufficiently large group, arrived at by majority voting, is almost certain to be correct (Condorcet 1785). The phenomenon of the “wisdom of crowds”, facilitated by cognitive diversity among individuals, provides further and arguably better support for the epistemic conception (Page 2007, Landemore 2012). But there are theoretical limits to the possibilities for collective judgment on matters of fact. Starting with Kornhauser and Sager’s (1986) discussion of group deliberation in legal settings, work on the theory of judgment aggregation has explored paradoxes and impossibility theorems closely related to those that Condorcet and Arrow discovered in connection with preference aggregation. See List (2012) and the entry social choice theory for overviews.