Central to Hume’s metaphysics and epistemology are his examinations of causation and probability. Central to his ethics are his examinations of virtue and vice. At the core of these examinations, in turn, lie his accounts of the origin and application of the corresponding concepts-that is, the abstract or general ideas-of causation, probability, virtue, and vice. Taken together, his accounts of these concepts are intended to explain a great deal about why human beings think and feel about the world and other people as they do. As we have seen in Chapter One, Hume’s earliest correspondence

reveals that his twin ambitions were to contribute to aesthetic criticism (particularly criticism of literature) and to philosophy. As also noted there, Norman Kemp Smith proposed that the “new scene of thought” that so inspired the young Hume lay in his realization that aspects of Hutcheson’s moral sense theory could be carried over to the realm of belief [1.1]. These two facts are not as unrelated as they might seem. First, Hume follows Hutcheson in seeing important parallels between aesthetics and morals, going so far as to describe virtue as “moral beauty” and to propose that beauty and virtue are each discerned by their own distinctive “sense.” Second, Hume’s treatments of both causation and probability appear, upon examination, analogous in many crucial respects to his treatments of both beauty and virtue. Kemp Smith also suggested that Hume actually composed Books 2

and 3 of the Treatise (“Of the Passions” and “Of Morals”) before Book 1 (“Of the Understanding”); in this, Kemp Smith certainly went far beyond what any textual evidence warrants. In describing

Hume as rejecting “evidence” in the theoretical domain in favor of feeling, he substantially misrepresented the nature of the parallels that exist. Nevertheless, given the earlier development in Hutcheson of conceptions of beauty and virtue as discerned by “senses,” it is not unreasonable to suppose that the parallels with causation and probability result at least in part from Hume’s extension, however conscious or unconscious, of the former to the latter. Without endorsing Kemp Smith’s thesis about the order of composition of the Books of the Treatise, therefore, it will be useful to consider the cases of beauty and virtue before those of causation and probability-and to consider the origins and shared features of the concepts themselves before turning in subsequent chapters to their distinctive applications. The full elaboration of their origins and shared features will require some extrapolation from his accounts of individual cases.