Interactive Causes: Revising the Markov Condition

This paper suggests a revision of the theory of causal nets (TCN). In Section 1 we introduce an axiomatization of TCN based on a realistic understanding. It is shown that the causal Markov condition entails three independent principles. In Section 2 we analyze inde-terministic decay as the major counterexample to one of these principles: screening-off by common causes (SCC). We call (SCC)-violating common causes interactive causes. In Sec-tion 3 we develop a revised version of TCN, called TCN*, which accounts for interactive causes. It is shown that there are interactive causal models that admit of no faithful non-interactive reconstruction