Arrow's Theorem in Judgement Aggregation

In response to recent work on the aggregation of individual judgements on logically connected propositions into collective judgements, it is often asked whether judgement aggregation is a special case of Arrowian preference aggregation. We argue the opposite. After proving a general impossibility theorem, we construct an embedding of preference aggregation into judgement aggregation and prove Arrow's theorem as a corollary of our result. Although we provide a new proof of Arrow's theorem, our main aim is to identify the analogue of Arrow's theorem in judgement aggregation, to clarify the relation between judgement and preference aggregation and to illustrate the generality of the judgement aggregation model.