INTEGRATING WORLD KNOWLEDGE AND LINGUISTIC CONSTRAINTS IN THE TEMPORAL INTERPRETATION OF WHEN SENTENCES

This article focuses on the problem of determining the qualitative tem poral constraints between the eventualities described by ''when'' sent ences. It faces the problem of integrating the purely linguistic tempo ral constraints provided by the anchoring of aspect and aktionsart of the ''when'' clause and of the main clause with the temporal constrain ts provided by the causal connections constituting the world knowledge . The modular approach we propose is based on the consideration that w orld knowledge and linguistic tools such as aspect and aktionsart work independently of each other: The former conveys temporal constraints between related eventualities, while the latter provide the temporal p erspectives selected by the speaker. Thus, independent modules are pro posed which: (1) represent the causal information and reason with it, extracting the qualitative temporal constraints between the eventualit ies regardless of the temporal perspectives introduced by the descript ions of the speaker; (2) determine (considering aspect and aktionsart) the temporal content of the clauses considered in isolation (and, in particular, the temporal perspectives introduced by the speaker); (3) anchor the temporal perspectives of the main clause and of the ''when' ' clause; and (4) integrate the qualitative temporal constraints deter mined by (1), (2), and (3), to arrive at a single, integrated interpre tation of the ''when'' sentence as a whole. (C) 1996 John Wiley & Sons , Inc.