EPDL: A Logic for Causal Reasoning

Abstract

This paper is twofold. First, we presentes an extended system EPDL of propositional dynamic logic by allowing a proposition as a modality in order to represent and specify indirect effects of actions and causal propagation. An axiomatic deductive system is given which is sound and complete with respect to the corresponding semantics. The resultant system provides a unified treatment of direct and indirect effects of actions. Second, we reduce the EPDL into a mutlimodal logic by deleting the component of action in order to obtain an axiomatized logical system for causal propagation. A characterization theorem of the logic is given. Properties of causal reasoning with the logic are discussed.