In part 2 we showed how the concepts of ability and belief could be given formal definition in the metaphysically adequate automaton model and indicated the correspondence between these formal concepts and the corresponding commonsense concepts. We emphasized, however, that practical systems require epistemologically adequate systems in which those facts which are actually ascertainable can be expressed.

In this part we begin the construction of an epistemologically adequate system. Instead of giving formal definitions, however, we shall introduce the formal notions by informal natural-language descriptions and give examples of their use to describe situations and the possibilities for action they present. The formalism presented is intended to supersede that of McCarthy (1963).

Mon Apr 29 19:20:41 PDT 1996