Generative Lexicon

Generative Lexicon (GL) is a theory of linguistic semantics which focuseson the distributed nature of compositionality in natural language. The first major work outlining the framework is James Pustejovsky's "Generative Lexicon" (1991). Subsequent important developments are presented in Pustejovsky and Boguraev (1993), Bouillon (1997), and Busa (1996). The first unified treatment of GL was given in Pustejovsky (1995). Unlike purely verb-based approaches to compositionality, Generative Lexicon attempts to spread the semantic load across all constituents of the utterance. Central to the philosophical perspective of GL are two major lines of inquiry:(1) How is it that we are able to deploy a finite number of words inour language in an unbounded number of contexts?(2) Is lexical information and the representations used in composingmeanings separable from our commonsense knowledge?

Motivation

GL was initially developed as a theoretical frameworkfor encoding selectional knowledge in naturallanguage. This in turn required making some changes in the formalrules of representation and composition. Perhaps the mostcontroversial aspect of GL has been the manner in which lexicallyencoded knowledge is exploited in the construction of interpretationsfor linguistic utterances. Thecomputational resources available to a lexical item within this theory consist of thefollowing four levels:

#Lexical Typing Structure: giving an explicit type for a word positioned within a type system for the language;
#Argument Structure: specifying the number and nature of the arguments to a predicate;
#Event Structure: defining the event type of the expression and any subeventual structure it may have; with subevents;
#Qualia Structure: a structural differentiation of the predicative force for a lexical item.

Qualia Structure

The qualia structure, inspired by Moravcsik's (1975) interpretation of the "aitia" of Aristotle, are defined by Pustejovsky as the modes of explanationassociated with a word or phrase in the language, and are defined as follows:

#"formal": the basic category of which distinguishes the meaning of a word within a larger domain;
#"constitutive": the relation between an object and its constituent parts;
#"telic": the purpose or function of the object, if there is one;
#"agentive": the factors involved in the object's origins or ``coming into being".

References

*Bouillon, P. 1997. "Polymorphie et semantique lexical: le case des adjectifs", Ph.D., Paris VII. Paris.
*Busa, F. 1996. Compositionality and the Semantics of Nominals, Ph.D. Dissertation, Brandeis University.
*Moravcsik, J. M. 1975. "Aitia as Generative Factor in Aristotle's Philosophy", Dialogue, 14:622-36.
*Pustejovsky, J. (1991) "The Generative Lexicon", in Computational Linguistics, 17.4.
*Pustejovsky, J. (1995) The Generative Lexicon, MIT Press, Cambridge, MA.
*Pustejovsky, J. and B. Boguraev. (1993) "Lexical Knowledge Representation and Natural Language Processing", in Artificial Intelligence, 63:193-223.