cuted actions. It has been applied to several challenge problems in the theory of commonsense knowledge. We study the relationship between this formalism and other work on nonmonotonic reasoning and knowl-.

In this dissertation, we investigate the role of causal knowledge in commonsense reasoning about action and change. We define a language in which a relatively simple form of causal knowledge is expressed. Using this language, we describe a novel approach to formalizing action domains as "causal theories"--including domains that involve concurrency, nondeterminism, and things that change by themselves. We show that a subclass of causal theories can be translated into propositional logic by a generalization of Clark's completion procedure for logic (...) programs. Finally, we describe an implemented approach to automated query answering and "satisfiability planning" which is based on this translation. (shrink)