Hume's Defence of Causal Inference (review)

According to its introduction, this book "deals solely with the problem of induction [and] solely with the issue of whether Hume is a sceptic with regard to causation and scientific reason" (p. 6). Wilson concludes that although Hume rejects "objective" necessary connections, he is not a sceptic—or at least, no more than a fallibilist "academic" sceptic—about induction. In contrast to several relatively recent commentators, he accepts the traditional view that Hume did pose a general sceptical problem about induction. One of Wilson's many formulations of that problem (111) is this: "How can [inductive] inference habits be justified, shown to be reasonable?" According to Wilson, Hume raised this problem and offered a solution to it. In fact, he holds, Hume provided at least the outlines of the correct solution.

The book consists of just three chapters, but each chapter is over one hundred pages long. Not surprisingly, then, it is not really devoted solely to the question of whether Hume was or was not a sceptic about induction. In fact, the book takes up a wide variety of other related topics, incorporating considerable amounts of material from no fewer than thirteen of Wilson's previously-published articles. It helpfully formalizes arguments wherever possible.

The first chapter is a series of set-pieces intended to prepare the way for more tightly focused discussion of Hume's treatment of inductive scepticism. Topics include Hume's two definitions of 'cause,' necessary connections, dispositions, mental activity, the epistemology of scientific instruments, and Hume's treatment of "scepticism with regard to the senses." One recurring theme is that Hume is no proto-Kantian about mental activity or the universality of causation; another is the importance to Hume of his "Rules by which to judge of causes and effects."

The second chapter is the centerpiece of the book, for it is here that Wilson tries to show how Hume justifies inductive scientific reasoning. The justification, as Wilson reconstructs it, has two steps. The first step is to argue that we ought to make inductive inferences on the grounds that (as a matter of psychological necessity) we must make such inferences. But this is only half the battle, since there are various ways to make inductive inferences and various strategies and influences that might or might not be allowed to affect the outcome. Hume's chosen way of making inductive inferences, Wilson argues, is the scientific method of "eliminative induction," as embodied in the "Rules by which to judge of causes and effects." Hume's strategy for justifying this method, according to Wilson, is to show that it is "reasonable" by showing that it is the method best suited for a particular practical purpose—namely, the purpose of satisfying our passion of "curiosity." This passion aims not only at the pleasure of exercising our faculties, but also at the achievement of truth, or at least (what seems rather different) of a system of beliefs that will prove "satisfactory to the mind." Accordingly, Wilson takes Hume to argue that using the method of eliminative induction embodied in the "Rules" constitutes "the best we can do" by way of discovering the truth of generalizations and that experience shows other methods to be less satisfactory in attaining the truth. Of course, a method's being the best we can do does not in itself entail that it is good enough to warrant adoption; and to treat the past successes or failures of a particular method as indicative of its future success or failure is to rely on induction itself. Presumably, then, Wilson's Hume is meant to regard the inductive arguments showing the "reasonableness" of the "Rules" as themselves among the inductions that any human being ultimately must accept, regardless of specific methods, strategies, or influences.

The book's third and final chapter takes up the challenge posed by the section of Hume's Treatise of Human Nature entitled "Of scepticism with regard to reason," in which Hume argues that "all the rules of logic...