  We present a precise definition of cause and effect in terms of a fundamental
notion called unresponsiveness. Our definition 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 beneficial 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 influence diagrams in canonical form are an accurate and efficient
representation of causal relationships. In addition, we establish a
correspondence between canonical form and Pearl's causal theory.
