A Hamblin Semantics for Evidentials

When speakers enter a conversation, they do so with a shared body of information. As the participants in the conversation speak, what they say affects this common ground. But how exactly is the common ground affected by what they assert? On one view, an assertion updates the common ground (Karttunen 1974, Stalnaker 1975, 1978). A second view is that an assertion is a proposal to update the common ground. This is the view taken in recent work on Inquisitive Semantics (e.g., Groenendijk 2009) and inspired by earlier work on the information structure of discourse (Ginzburg 1996, Roberts 1996, Gunlogson 2001). What the conversational participants say contains elements which are associated with various kinds of meanings. One distinction that has been made is between the at-issue content of an utterance, the ‘main point’, and the content which is not at-issue (Potts 2005, Papafragou 2006, Simons 2007, Amaral et al. 2007). This distinction has been used to analyze various phenomena, including some parentheticals, parenthetical uses of embedding verbs, and epistemic modals. In this paper, I propose that the distinction between what is at-issue and what is not can be modeled as a distinction between two components of assertion. These two components affect the common ground in different ways. The at-issue component of an assertion, which is negotiable, is treated as a proposal to update the common ground. The not-at-issue component of an assertion, which is not negotiable, is added directly to the common ground. Evidence for this proposal comes from evidentials, which I argue grammaticize this distinction. It has been observed that sentences with evidentials make both an ‘evidential’ and a ‘propositional’ contribution (Faller 2002, 2006, Matthewson et al. 2008). The evidential contribution is not directly challengeable or up for negotiation. In contrast, the propositional contribution, the ‘main point’ of the sentence, is directly challengeable and up for negotiation. I analyze these two contributions of evidentials as the not-at-issue component of assertion and the at-issue component of assertion, respectively. Supporting data comes from Cheyenne, a language with evidentials that are part of the illocutionary mood paradigm.