Reasoning dynamically about what one says

In this paper we make SDRT’s glue logic for computing logical form dynamic. This allows a dialogue agent to anticipate what the update of the semantic representation of the dialogue would be after his next contribution, including the effects of the rhetorical moves that he is contemplating performing next. This is a pre-requisite for planning what to say next. We make the glue logic dynamic by extending a dynamic public announcement logic (PAL) with the capacity to perform default reasoning—an essential component of inferring the pragmatic effects of one’s dialogue moves. We add to the PAL language a new type of announcement, known as ceteris paribus announcement, and this is used to model how an agent anticipates the default consequences of his next dialogue move. Our extended PAL validates more intuitively compelling patterns of default inference than existing PALs for practical reaosning, and we demonstrate via the proof of reduction axioms that the dynamic glue logic, like its static version, remains decidable.