Proceedings of the Annual Meeting of the Cognitive Science Society

Representing and reasoning about goal-directed actions is necessary in order for autonomous agents to act in or understand the commonsense world. This paper provides a formal theory of in- tentional action based on Bratman's characteriza- tion of intention [Bratman, 1987, Bratman, 1990]. Our formalization profits from the the formaliza- tion of Bratman's theory developed by Cohen and Levesque [l990a, 1990bJ. W e review their formal- ization and illustrate its weaknesses. Using Allen's temporal logic [Allen, 1984] , w e construct a for- malization that satisfies Bratman's desiderata for an acceptable theory of intentional action. W e in- troduce a characterization of success and failure of intentional action and show that our richer theory of time allows us to formalize more complex inten- tional actions, particularly those with deadlines. Finally, we argue that the use of a syntactic theory of belief allows us to accommodatea more descrip- tive theory of intentional action by fallible agents. Our work has relevance to multi-agent planning, speech-act processing and narrative understand- ing. W e are using this theory to representing the content of narratives and to constructing and un- derstanding description-based communication.