Abstract

This paper introduces and studies a notion of cautious distributed belief. Different from the standard distributed belief, the cautious distributed belief of a group is inconsistent only when all group members are individually inconsistent. The paper presents basic results about cautious distributed belief, investigates whether it preserves properties of individual belief, and compares it with standard distributed belief. Although both notions are equivalent in the class of reflexive models, this is not the case in general. While we argue that an understanding of the concept of cautious distributed belief from first principles is important, cautious distributed belief can be expressed using standard distrbuted belief and we show that the propositional language extended only with cautious distributed belief is in fact strictly less expressive than the propositional language extended only with standard distributed belief. We, finally, identify a small extension of the language making the former as expressive as the latter.