Individual Coherence and Group Coherence

Paradoxes of individual coherence (e.g., the preface paradox for individual judgment) and group coherence (e.g., the doctrinal paradox for judgment aggregation) typically presuppose that deductive consistency is a coherence requirement for both individual and group judgment. In this paper, we introduce a new coherence requirement for (individual) full belief, and we explain how this new approach to individual coherence leads to an amelioration of the traditional paradoxes. In particular, we explain why our new coherence requirement gets around the standard doctrinal paradox. However, we also prove a new impossibility result, which reveals that (more complex) varieties of the doctrinal paradox can arise even for our new notion of coherence. 1. Individual Coherence 1.1. Deductive Consistency: The Recent Dialectic. It is often assumed that an epistemically rational agent’s (full) beliefs ought to be deductively consistent. That is, the following is often taken to be a (synchronic) epistemic coherence requirement for individual agents. (CB) Consistency Norm for Belief. Epistemically rational agents should (at any given time) have logically consistent belief sets. One popular motivation for imposing such a requirement is the presupposition that epistemically rational agents should, in fact, obey the following norm: Date: Septmeber 16, 2013. Draft: final version to appear in Essays in Collective Epistemology, J. Lackey (ed.), Oxford University Press.