Pushing the edge of the ( QP ) envelop

Abstrac t Qualitative Process theory has been successfully used to model a variety of domain s and in exploring several qualitative reasoning tasks. However, there has been little explicit analysis of where and how it breaks down. The purpose of this paper is to look a t several ways in which QP theory (or implementations of it) currently fail in some way. Two concepts for classifying QP models are introduced and used to clarify some assumptions underlying all existing qualitative simulators. The relationship between QP theory , QPE, and human intuition is shown to be more complicated than previously suspected. Finally, some limitations of QP theory relative to other systems of qualitative physics are explored. While the analysis focuses on QP theory, many of the issues and suggeste d research directions are applicable to other systems of qualitative physics as well .