In this revised and updated edition of The Secret Connexion, Galen Strawson explores one of the most discussed subjects in all philosophy: David Hume's work on causation. Strawson challenges the standard view of Hume, according to which he thinks that there is no such thing as causal influence, and that there is nothing more to causation than things of one kind regularly following things of another kind. He argues that Hume does believe in causal influence, but insists that we cannot know its nature. The regularity theory of causation is indefensible, and Hume never adopted it in any case.