The main focus of writing on Keynes and philosophy has long been his theory of probability and the related notion of uncertainty. For Keynes questions of probability only arose in circumstances of uncertainty so the two ideas are inherently connected. In a footnote to the General Theory Keynes invited readers to compare his discussion of uncertainty there with his highly philosophical treatment of the same topic in his earlier book, A Treatise of Probability, which grew out of the young Keynes’s interest in Moore’s Principia Ethica. In his 1937 “The General Theory of Employment,” he called further attention to the philosophical side of uncertainty in the course of what he called a “general philosophical disquisition on the behaviour of mankind” (Keynes 1971-89, 14: 115). Despite these hints, Keynes’s invitation to consider the philosophical side of uncertainty was ignored for many years. G.L.S. Shackle, in his Years of High Theory (1967), was among the first to emphasize the connection between the two books and in the 1970s and 1980s, with the rise of post-Keynesianism, a few more economists began to take Keynes’s discussion of expectations seriously, for example, Jan Kregel (1976). It was only in Anna Carabelli’s pathbreaking On Keynes’s Method (1988) that we find the first systematic interpretation of the General Theory grounded on a thorough analysis of the Probability. Soon afterward Rod O’Donnell (1989) offered a similar but distinct interpretation based not only on the Probability, but also on an exhaustive study of unpublished materials at the Keynes archive at King’s College, Cambridge. Carabelli and O’Donnell both argued that the Probability provided a broad theory of human behavior in general under conditions of uncertainty upon which the reasoning of the General Theory was based. Later John Davis (1994a) and Brad Bateman (1996) argued that Keynes abandoned the central contribution of the Probability well before he began to write the General Theory, even though uncertainty continued to have a central role in Keynes’s philosophy. In recent years a vibrant and growing literature has developed around the connection between the Probability and the General Theory along with the central concepts of probability and uncertainty, for example Runde and Mizuhara (2003). But to look at Keynes’s philosophy taking probability and uncertainty as central elements is to look at it from the perspective of his later economics and

not from the perspective of what he was imbibing in his youth. This is not to say that this literature is uninteresting or unimportant, but it does take the route against which Keynes warned. Probability was the focus of Keynes’s own efforts for many years, but in relation to the philosophy of his youth it was clearly secondary. Keynes accepted Moore’s view that a discussion of ethics must precede the discussion of conduct, that ends must be addressed before means, or in Keynes’s terms, morals are subordinate to religion. Questions of probability arose in the discussion of conduct and not in ethics proper and were ultimately subsidiary. Morals, for Keynes, were concerned with how people should act, that is, with duty. Duty, like the notion of objective good, is a concept that was extremely important in Victorian and Edwardian England, but was hollowed out with the decline of objective notions of goodness. In its ethical sense, duty refers to what one should do and carries some connotation of moral obligation independent of one’s subjective inclinations. This would seem to depend on an objective notion of goodness. If someone were to say “I feel that it is my duty to do such and such,” this is to say something different from “I want to do such and such” or “I think it would be good for me to do such and such.” With duty there is a suggestion of an external and objective standard from which an obligation derives. With the rise of virtue ethics, moral duty has become less clear and more complicated, at least in academic debate. For those like the young Keynes and his friends, who believed in the objectivity of goodness, questions of duty and good conduct were vitally important, encompassing all aspects of behavior, including not only political and economic activities, but also decisions about questions of daily life and mundane and ordinary human interaction. Two factors complicate any examination of Keynes’s position on ethical conduct. First, even during the period before the First World War, when they felt Moore’s influence most directly, Keynes and his friends had already rejected some of his main conclusions with respect to conduct. Second, conduct is the area in which the later Keynes was most critical of his early beliefs. It was here that Keynes identified the key flaw in his early beliefs that gave rise to his dramatically mistaken optimism after 1903 and before the First World War. As a result it is with respect to conduct that his thought changed the most. These changes are described in occasional hints rather than forming the focus of any detailed account. We therefore have neither a systematic description of Keynes’s early views on conduct corresponding to the statement of his views on ethics contained in Principia Ethica, nor a clear analysis of their evolution. In order to approach Keynes’s views on conduct, this chapter begins with Sidgwick’s Methods of Ethics (1907), the most important context for understanding Moore’s views on conduct. Sidgwick’s approach was decidedly Coleridgean in two important and related ways. First, he began from what I have called an anthropological perspective, taking the actual moral reasoning of people as the phenomenon to be explained. The approach of Sidgwick’s book was Coleridgean in another important sense, that is, in its assumption that almost every point of view reflects important truths that, despite appearances, are not

contradictory and can be reconciled. He identified three methods of ethics: egoism, intuitionism, and utilitarianism. He explicated each one as fairly as he could and then attempted to show that the three might be reconciled. He was unsuccessful. He believed he was able to successfully reconcile intuitionism and utilitarianism but was unable to reconcile utilitarianism and egoism. Keynes’s mature views on ethics were shaped by Moore’s responses to these conclusions.