Providing A Unified Account Of Definite Noun Phrases In Discourse
by Grosz, Barbara J., Joshi, Aravind K., Weinstein, Scott
Technical Note 292
Institution: AI Center, SRI International
Address: 333 Ravenswood Ave., Menlo Park, CA 94025
Note: This paper appears in Proceedings of the 21st Annual Meeting of the Association for Computational Linguistics, Boston, MA, June 1983. This research was supported in part by the National Science Foundation under Grant MCS-8115105 to SRI International and Grant MCS81-07290 to the University of Pennsylvania.
Linguistic theories typically assign various linguistic phenomena to one of the categories, syntactic, semantic, or pragmatic, as if the phenomena in each category were relatively independent of those in the others. However, various phenomena in discourse do not seem to yield comfortably to any account that is strictly a syntactic or semantic or pragmatic one. This paper focuses on particular phenomena of this sortthe use of various referring expressions such as definite noun phrases and pronounsand examines their interaction with mechanisms used to maintain discourse coherence. Even a casual survey of the literature on definite descriptions and referring expressions reveals not only defects in the individual accounts provided by theorists (from several different disciplines), but also deep confusions about the roles that syntactic, semantic, and pragmatic factors play in accounting for these phenomena. The research we have undertaken is an attempt to sort out some of these confusions and to create the basis for a theoretical framework that can account for a variety of discourse phenomena in which all three factors of language use interact. The major premise on which our research depends is that the concepts necessary for an adequate understanding of the phenomena in question are not exclusively either syntactic or semantic or pragmatic. The next section of this paper defines two levels of discourse coherence and describes their roles in accounting for the use of singular definite noun phrases. To illustrate the integration of factors in explaining the uses of referring expressions, their use on one of these levels, i.e., the local one, is discussed in Sections 3 and 4. This account requires introducing the notion of the centers of a sentence in a discourse, a notion that cannot be defined in terms of factors that are exclusively syntactic or semantic or pragmatic. In Section 5, the interactions of the two levels with these factors and their effects on the uses of referring expressions in discourse are discussed.