Transitivity and proportionality in causation

It is widely assumed that causation is transitive, but putative counterexamples abound. These examples come in three varieties: switching cases, short circuit cases, and what I will call mismatch cases. In this paper I focus on the mismatch variety, which is widely taken to be the easiest to resolve. I will first introduce the cases and the existing strategy for dealing with them, then present a new counterexample which is immune to that strategy. In response to this new counterexample I will introduce a novel solution, one drawing on Yablo’s proportionality principle for causation. There is a catch, however. Either proportionality is a strong constraint—it constrains which causal claims are true—and the solution works, or it is not and causation is not transitive after all. I will argue that the first horn has unacceptable consequences and should be rejected, but that the second horn may be less costly than it initially appears.