Despite its popularity, deliberative democracy has not sufficiently dealt with the epistemic problems raised by the tension between its desire for inclusivity and the need to maintain appropriate standards of evidence and reason-giving. While a broad consensus has emerged suggesting that one of deliberative democracy’s strengths is its potential to include a plurality of views in deliberative encounters, as opposed to limiting the scope of perspectives that might be included, such positions leave deliberative democrats in danger of accepting epistemic positions that would fail any reasonable test of integrity. That deliberative democratic theorists have arrived at this point is understandable, given their concern with the potential for the exclusion of marginalised voices from the democratic process. However, deliberative democracy has yet to come up with an adequate account of the limits of such a position.
In this paper, I argue that these failings are exposed when considered alongside the kinds of argumentation employed by adherents of conspiracy theories. While, at first glance, conspiracy theories would seem to obviously preclude deliberation, a close examination suggests that most attempts to exclude them from deliberative settings are, as the literature currently stands, arbitrary and contrary to many of the principles espoused by deliberative democrats. This exposes a serious, but often hidden, problem in deliberative democratic theory as it is currently understood: most deliberative democrats want a procedure that is highly inclusive but there are few established means of ensuring that the epistemic quality of deliberative encounters is not compromised as a result. In response, in this paper I propose two possible means of addressing this issue. First, by considering the ways in which deliberative democrats have already attempted to impose limits on deliberation. Second, by introducing some potentially-useful epistemic standards which contrast with the existing approaches in the literature.