On the Availability of Presuppositions in Conversation

Presuppositions—information speakers mutually take for granted in conversation—play important explanatory roles in pragmatics and semantics. This chapter argues that not all presuppositions in a conversation are equally available, or accessible, to speakers at a given stage in a conversation. Contrary to common assumption, some pieces of information may be presupposed yet not be available to speakers for conversational actions. Standard conceptions of the conversation’s common ground—the set of presuppositions—cannot account for such differences in availability. This chapter presents an account of the common ground that makes room for a notion of availability of presuppositions relative to a conversational task. The notion is implemented in a conception of a Fragmented Common Ground that draws on three independently motivated ideas: the notion of context as common ground, mental fragmentation, and questions as guiding and structuring discourse.