Disambiguation as (Defeasible) Reasoning about Underspecified Representations

UNDERSPECIFIED REPRESENTATIONS have been proposed as a way of formalizing sentence disambiguation in terms of (usually, nonmonotonic) reasoning. But in fact the existing theories about the semantics of underspecified representations either fail to capture our intuitions about ambiguity, or lead one to believe that the kind of inferences used in disambiguation have nothing to do with what we usually mean by inference. As a solution, I propose a theory of underspecification based on two hypotheses: that disambiguation is the task of recovering the content of the utterance events that take place in a discourse situation; and every utterance event that took place in a conversation, including utterances of single lexical items, is recorded in the common ground. The underspecified representations I propose are representations of what took place in the discourse situation, rather than directly about the content of an utterance. It is shown that the resulting theory of underspecification offers a more satisfactory account of lexical disambiguation and is more general that existing theories, in that can also be used to account for structural disambiguation.