A De nition and Graphical Representation for Causality

We present a precise deenition of cause and eeect in terms of a fundamental notion called unresponsiveness. Our deenition is based on Savage's (1954) formulation of decision theory and departs from the traditional view of causation in that our causal assertions are made relative to a set of decisions. An important consequence of this departure is that we can reason about cause locally, not requiring a causal explanation for every dependency. Such local reasoning can be beneecial because it may not be necessary to determine whether a particular dependency is causal to make a decision. Also in this paper, we examine the graphical encoding of causal relationships. We show that innuence diagrams in canonical form are an accurate and ee-cient representation of causal relationships. In addition, we establish a correspondence between canonical form and Pearl's causal theory.