The formalism presented in part 3 is, we think, an advance on previous attempts, but it is far from epistemological adequacy. In the following sections we discuss a number of problems that it raises. For some of them we have proposals that might lead to solutions.

- The approximate character of
- Possible Meanings of `can' for a Computer Program
- The Frame Problem
- Formal Literatures
- Probabilities
- Parallel Processing

Mon Apr 29 19:20:41 PDT 1996