INTERPRETING PRESUPPOSITIONS USING ACTIVE LOGIC - FROM CONTEXTS TO UTTERANCES

Presupposition is a pervasive feature of human language. It involves m any interesting interactions between the utterances of a discourse and the context of the discourse. In this paper we focus on issues of log ical form connected with the interaction of presupposition and discour se context, and illustrate our theory with some implementational work using the active logic framework. After reviewing some of the major is sues in presupposition theory we turn to a largely successful unified approach of Helm. We show how the main principles of this theory can b e implemented in active logic. But we also find two serious difficulti es. These consist in (a) a straightforward counterexample and (b) a ty pe of discourse that we call a garden-path discourse. We maintain that both the counterexample and the garden-path type of discourse can be handled by our active-logic version of Helm's theory. This requires us to reformulate and extend Helm's theorey. Although this work is large ly theoretical, both Helm's theory and ours have important things to s ay about the incremental processing of the utterances that make up dis course. And we present our theory as a specification of a processing d evice that takes logical form of a sentence along with current discour se context as input and delivers an updated discourse context as outpu t. As an experiment, we have implemented portions of this device.