Qualitative Physics is an area of AI concerned with reasoning about the behaviour of physical systems.
It is a good area to study since humans know a great deal about this world:
However most humans whilst being to operate in this world have no notion of the laws of physics that govern this world.
We can clearly look up the information and derive equations to describe, say pendulum motion. Indeed computers are very good at this sort of computation when they have been programmed by experienced programmers.
Is this how an intelligent system functions in this world?
Three year old children can and cannot even read or do elementary maths?
One other motivation is that whilst complex computer models can be assembled many problems remain difficult or impossible to solve analytically. Systems of equations (differential etc.) might hard to derive and even impossible to solve.