easoning," Proceedings of the Eighth National Conference on Artificial Intelligence, AAAI Press, Menlo Park, CA (1990), pp. 538- 544. (6.) E Davis, The Naive Physics Perplex," AI Magazine 19, No. 4, 51-79 (1998). (7.) D. Lenat, "Cyc: A Large-Scale Investment in Knowledge Infrastructure," Communications of the ACM 38, No