Semantic Ambiguity and Perceived Ambiguity

TL;DR

This paper develops a formal theory connecting semantic ambiguity in natural language with underspecification, proposing a framework that models different ambiguity types and how humans interpret them, using default logic.

Contribution

It introduces a formal underspecified language capturing lexical, scopal, and referential ambiguities, linking NLP, semantics, and psychology, with a defeasible reasoning formalization.

Findings

Formalizes an underspecified language for semantic ambiguities

Models human ambiguity resolution using default logic

Discusses challenges in formalizing ambiguity reasoning

Abstract

I explore some of the issues that arise when trying to establish a connection between the underspecification hypothesis pursued in the NLP literature and work on ambiguity in semantics and in the psychological literature. A theory of underspecification is developed `from the first principles', i.e., starting from a definition of what it means for a sentence to be semantically ambiguous and from what we know about the way humans deal with ambiguity. An underspecified language is specified as the translation language of a grammar covering sentences that display three classes of semantic ambiguity: lexical ambiguity, scopal ambiguity, and referential ambiguity. The expressions of this language denote sets of senses. A formalization of defeasible reasoning with underspecified representations is presented, based on Default Logic. Some issues to be confronted by such a formalization are discussed.