Against Lewis’s New Theory of Causation: A Story with Three Morals

A recent paper by David Lewis, “Causation as Influence”, provides a new theory of causation. This paper presents an argument against the theory, using a series of counterexamples that are, I think, of independent interest to philosophers of causation. I argue that (a) the relation asserted by a claim of the form “C was a cause of E” is distinct from the relation of causal influence, (b) the former relation depends very much, contra Lewis, on the individuation conditions for the event E, and (c) Lewis’s account is unsatisfactory as an analysis of either kind of relation. The counterexamples presented here provide, I suggest, some insight into the reasons for the failure of counterfactual accounts of causal relations. David Lewis’s new account of causation (Lewis 2000) is, I believe, mistaken, but it is mistaken in instructive ways. In what follows, I present an argument against the account, based on a scenario that I claim constitutes a simple counterexample to all three of Lewis’s counterfactual accounts of causation, and I draw several broad morals for the study of the truth conditions of claims of the form “C is a cause of E”.