At-issue Proposals and Appositive Impositions in Discourse

Potts (2005) and many subsequent works have argued that the semantic content of appositive (non-restrictive) relative clauses, e.g., the underlined material in John, who nearly killed a woman with his car, visited her in the hospital, must be in some way separate from the content of the rest of the sentence, i.e., from at-issue con-tent. At the same time, there is mounting evidence from various anaphoric processes that the two kinds of content must be inte-grated into a single, incrementally evolving semantic representa-tion. The challenge is how to reconcile this informational sepa-ration with these pervasive anaphoric connections. We propose a dynamic semantic account that accomplishes this by taking ap-positive and at-issue content to involve two different kinds of up-dates to the Context Set (CS). Treating the context set as a distin-guished propositional variable, pcs, we argue that appositives di-rectly impose their content on the CS by eliminating possible values assigned to pcs. In contrast, we treat at-issue assertions as intro-ducing a new propositional dref and proposing that pcs be updated with its content, subject to addressee’s response. In addition to capturing the behavior of appositives in discourse, we show that the account can be extended to capture the projection of apposi-tive content past various sentential operators.