 Among the most widely discussed theories of the basing relation is that presented by Marshall Swain (1979, 1981, and 1985). Concerned about superstitious-lawyer style counterexamples, Swain suggests that a counterfactual analysis of causation may avoid them without doing violence to the intuitions underlying causal theories of the basing relation. A counterfactual statement is a statement of the form “If A were to occur, then B would occur”, where ‘A’ and ‘B’ denote events. Roughly, the idea is that a belief is based on a reason if the reason either non-deviantly causes or would have caused (in the appropriate circumstances) the belief in question. Very roughly, where the reason would have caused the belief (in the appropriate circumstances), the reason is, in Swain’s terminology, a pseudo-overdeterminant of the belief, and hence the belief is based on it. Swain argues that the complicated line of reasoning is a pseudo-overdeterminant of the lawyer’s belief that his client is innocent, and hence that there is a kind of causal connection between the complicated line of reasoning and the lawyer’s belief by virtue of which the lawyer’s belief is based on the reasoning. Swain more precisely defines pseudo-overdeterminants as follows (1981, p. 70):