A logical framework for commonsense predictions of solid object behaviour

Predicting the behaviour of a qualitatively described system of solid objects requires a combination of geometrical, temporal, and physical reasoning. Methods based upon formulating and solving differential equations are not adequate for robust prediction, since the behaviour of a system over extended time may be much simpler than its behaviour over local time. This paper presents a first-order logic in which one can state simple physical problems and derive their solution deductively, without recourse to solving differential equations. This logic is substantially more expressive and powerful than any previous AI representational system in this domain.