The Counterfactual Analysis of Cause

David Lewis’s counterfactual analysis of cause consisted of the counterfactual conditional closed under transitivity.2 Namely, a sufficient condition for A’s being a cause of C is that ∼A>∼C be true; and a necessary as well as sufficient condition is that there be a series of true counterfactuals ∼A>∼E1, ∼E1 >∼E2, . . . , ∼En >∼C (n> 0). At the core of this analysis, cause is taken to be transitive; namely, if A is a cause of B and B of C, then A is a cause of C. I have argued, however, that cause is not transitive,3 which, if correct, undermines Lewis’s analysis.4 Specifically, consider the following counter-example to the transitivity of cause: