tailieunhanh - Báo cáo khoa học: "A Uniform Treatment of Pragmatic Inferences in Simple and Complex Utterances and Sequences of Utterances"

Drawing appropriate defeasible inferences has been proven to be one of the most pervasive puzzles of natural language processing and a recurrent problem in pragmatics. This paper provides a theoretical framework, called stratified logic, that can accommodate defeasible pragmatic inferences. The framework yields an algorithm that computes the conversational, conventional, scalar, clausal, and normal state implicatures; and the presuppositions that are associated with utterances. The algorithm applies equally to simple and complex utterances and sequences of utterances. . | A Uniform Treatment of Pragmatic Inferences in Simple and Complex Utterances and Sequences of Utterances Daniel Marcu and Graeme Hirst Department of Computer Science University of Toronto . Toronto Ontario Canada M5S 1A4 marcu gh Abstract Drawing appropriate defeasible inferences hits been proven to be one of the most pervasive puzzles of natural language processing and a recurrent problem in pragmatics. This paper provides a theoretical framework called stratified logic that can accommodate defeasible pragmatic inferences. The framework yields an algorithm that computes the conversational conventional scalar clausal and normal state implicatures and the presuppositions that are associated with utterances. The algorithm applies equally to simple and complex utterances and sequences of utterances. 1 Pragmatics and Defeasibility It is widely acknowledged that a full account of natural language utterances cannot be given in terms of only syntactic or semantic phenomena. For example Hirschberg 1985 has shown that in order to understand a scalar implicature one must analyze the conversants beliefs and intentions. To recognize normal state implicatures one must consider mutual beliefs and plans Green 1990 . To understand conversational implicatures associated with indirect replies one must consider discourse expectations discourse plans and discourse relations Green 1992 Green and Carberry 1994 . Some presuppositions are inferrable when certain lexical constructs fac-tives aspectuals etc or syntactic constructs cleft and pseudo-cleft sentences are used. Despite all the complexities that individualize the recognition stage for each of these inferences all of them can be defeated by context by knowledge beliefs or plans of the agents that constitute part of the context or by other pragmatic rules. Defeasibility is a notion that is tricky to deal with and scholars in logics and pragmatics have learned to circumvent it or live with it. The first observers of