DAVID HUME HIS THEORY OF KNOWLEDGE AND MORALITY by D* g: cy macnabb, m.a. \ v\ FELLOW AND LECTURER IN PHILOSOPHY, PEMBROKE COLLEGE, OXFORD Second Edition ARCHON BOOKS HAMDEN, CONNECTICUT FIRST PUBLISHED 195 I SECOND EDITION 1966 Printed in the United States of America 1.9 % CONTENTS Page Preface 5 Biographical Note g Introduction 13 Part One hume’s account of the understanding Chapter I. The doctrine of Impressions and Ideas 1. The distinction as drawn by Hume 23 2. The true basis of the distinction 25 3. The derivation of ideas from experience 27 Chapter II. Abstract Ideas 1. Realism, conceptualism and nominalism 33 2. Hume’s advance on Berkeley’s nominalism 36 Chapter III. Knowledge and Probability 1. The four kinds of assurance 40 2. Relations of ideas and matters of fact 43 3. A priori and empirical propositions 46 Chapter IV. Causality 1. Factual inferences and causal relations 49 2. The relation of cause and effect 50 3. Our conviction that every event has a cause 55 4. Our beliefs in specific causal connexions 59 Chapter V. Belief 1. The nature and causes of belief 68 2. States of mind which simulate belief 76 Chapter VI. Probability 1. The probability of chances and the probability of causes 83 2. Habit and expectation 92 3. Unphilosophical probability 94 4. Scepticism 100 3 4 , Chapter VII. Necessary Connexion Page 1. The question and the answer 103 2. The importance of the answer 107 3. Objections to Hume’s answer 112 Chapter VIII. Bodies 1. The problem 118 2. Hume’s “solution ” 123 3. Criticism of Hume’s “solution” 129 Chapter IX. Minds 1. Outline of Hume’s views 137 2. The errors of metaphysicians 139 3. Self-consciousness and personal identity 146 Part Two hume’s account of morality Chapter I. Introductory 155 Chapter II. The Servitude of Reason 1. Reason alone never influences action 159 2. The indirect influence of reason on action 163 3. The influence of “reason” improperly so-called 165 4. Challenge to Rationalists 167 Chapter III. The Artificiality of Justice 1. Nature, convention and the moral sentiment 171 2. The general argument for the artificiality of justice 173 3. The utility of justice and how it was discovered 176 4. The “moral beauty” of justice 180 5. Justice and self-interest ' 180 6. Justice and the public interest 182 Chapter IV. Sympathy and the Natural Virtues 1. The psychology of the moral sentiment 185 2. The correction of sympathy in moral judgements 191 Appendix: The Freedom of the Will 199 Index 205 4 PREFACE TO SECOND EDITION Since this book was written philosophy has moved on apace. Books have been published on epistemology, the philosophy of mind and on Hume, which have led me to form a somewhat different picture of Hume. I have principally in mind Ryle’s “Concept of Mind”,1 Wittgenstein’s “Philosophical In¬ vestigations”,2 Passmore’s “Hume’s Intentions”,3 R. H. Popkin’s “History of Scepticism from Erasmus to Descartes”,4 Flew’s “Hume’s Philosophy of Belief”5 and E. C. Mossner’s “Life of David Hume”.6 I would now wish to summarise Hume’s enterprise and the reasons for his failures in the following way. Hume was impressed by four things: the discordant and crazy conclusions of dogmatic metaphysicians and theologians, the logical strength of the arguments of the Sceptics, the suc¬ cesses of Newtonian science, and the importance of finding a satisfactory theory of morals. Scepticism was an ancient school of philosophy which professed to supply its disciple with a counter-argument for every argument he would ever meet. Thus armed he could kiss his hand to controversy and live quietly in accordance with natural instincts and local custom, thus achieving the “ataraxia” which all ancient philosophies pursued. Rediscovered at the Renaissance in the works of Sextus Empiricus, these arguments provided weapons for both sides in the religious controversies of the Reformation. Each side used them to discredit the reason¬ ing of its opponents and make room for its own brand of faith. But handy as these arguments were for theologians, they were an embarrassment to science, which claims to be founded not on faith, but on reason. Hume’s problem was so to use scepticism as to undermine 1 Hutchinson, 1949. 4 Martinus Nijhoff, The Hague, i960. 2 Basil Blackwell, 1953 5 Routledge & Kegan Paul, 1961. 3 Cambridge University Press, 1952 6 Nelson, 1954. 5 6 DAVID HUME > theology and metaphysics, but safeguard science and secular morality. His solution may be stated as follows. Arguments are only valid against arguments. Sceptical arguments therefore may be valid against arguments proposed to justify our trust in our senses, memory and the lessons of experience, but they are not valid against that trust itself, which is based on natural instincts indispensable to our survival. Instinct prevails against argument; “Nature by an . . . uncon¬ trollable necessity has determined us to judge as well as to breathe and feel”. Experimental science is but a refinement and extension of such judgements. Moreover it can be applied to the study of human nature. So applied it shows us the nature of deductive reasoning, based on the impossibility of conceiving a contradiction, and its application to experience through mathematics. It shows us the instinctive basis in habit-forma¬ tion of all empirical inferences concerning causes and effects. It shows us how human ingenuity has devised political and moral institutions which by their appeal to the natural prin¬ ciples of self-love and sympathy preserve society, without which men cannot survive. All these are natural, indispensable and irresistible principles. In contrast to them stand credulity, superstition, wishful thinking and prejudice. These are indeed common and in some conditions irresistible. But they are neither necessary nor desirable; we should be happier without them, and those whom we call men of sense reject tbeir influence when they detect it. They are also in another sense “unnatural” in that they depend on artificial causes, the artifices of priests and propagandists. Finally, unlike experience, they do not provide a single growing coherent picture of the world, but a welter of incompatible alternatives, and no means of deciding between them. Metaphysics, theology and scepticism have this in common, that they arise when reasoning, whether deductive or analogical, is applied beyond the sphere of common life, to which alone it is adapted. Scepticism is the only member of the trinity that is useful, for it can serve as a reminder of the limitations of our faculties. Such in outline is Hume’s attempt to limit faith in order to make room for science. The essence of it is “naturalism”, that is DAVID HUME 7 the treatment of the understanding as a natural function of the human species, subject to natural laws and conditions, adapted to natural needs and subject to natural infirmities. It is diametrically opposed to views like that of Descartes, who regarded the understanding as the power of an absolutely free will to assent or dissent according to or against the divine law of reason. I have two main criticisms. First, the programme is in part unnecessary. The sceptical arguments are not all unanswerable. Hume uses two kinds, which he does not clearly distinguish. Those of the first kind open up logical gaps—the gap between any object or event and any other, between sensations and objects, between relations of ideas and matters of fact, and between either of these last and judgements of value. These arguments are sound and constitute Hume’s major contribu¬ tions to philosophy, notwithstanding the spate of criticism which they have recently received. These arguments pose the problem, how, if at all, the gap is to be spanned. Quite different are the sceptical arguments Hume deploys to prove inherent contradictions in our understanding, for instance the “direct and total opposition between our reason and our senses”, the reduction of all probabilities to zero by successive considerations of our fallibility, and the riddle of the unity of consciousness. These are sophistries, and the problem they pose is to spot the fallacy. My second criticism is that Hume’s naturalism is not naturalistic enough. His analyses of the instinctive processes underlying our judgements of perception, probability and morality are stated in terms of “impressions” and “ideas”. These are treated not as natural functions of a flesh-and-blood animal, but as independent occurrences, many of them “not susceptible of local conjunction”, and private to the person who has them. They are the fragmented relics of the “ghost in the machine”, the immaterial soul-substance which Hume him¬ self derides. They are not genuine empirical entities, but the stock in trade of a theory—the “Philosophy of Ideas”. This is the error attacked in Ryle’s “Concept of Mind”, and it vitiates what I say in Part I, Chapters VIII and IX, as well as what Hume says about sense-perception, induction and personal identity. If we accept the view that all knowledge is either 8 DAVID HUME • indubitable datum or deduction from such, and impressions (or sense-data) as the only indubitable data, the sceptic has won the game at the first move, and our world can only end up as a construction of the imagination. Had Hume been consistently naturalistic, in keeping with the tone of his chapters on “the Reason of Animals”, he might have seen that what nature does, when, for example, we see something, is not'to force us to fill -the gaps in our sensations with vivid images, but to enable us to accommodate our behaviour to the object by using our eyes. For this is surely all that happens, as far as we can tell, when a dog sees a rabbit, and, as Hume says, the account that suffices for an animal suffices for the same thing in a human being. There is an historical error in the first edition of my book in Part I, Chapter III, Section 3, page 46. The pictures were in fact insured, thanks to the robust commonsense of the Head of the College. There is also I think a clear error of interpretation on pages 202 and 203. Professor Flew (“Hume’s Philosophy of Belief”, Chapter VIII) has convinced me that Hume in the “Enquiry concerning Human Understanding”, Section VIII, set out a decisive argument for the incompatibility of Theism and Determinism, and that the suggestions I make in mitigation of this argument are explicitly or implicitly rejected by Hume in the “Dialogues concerning Religion”. References to page numbers of the Treatise are to the Everyman Edition. References by paragraphs to the Enquiries are to the numbered paragraphs in L. A. Selby-Bigge’s (second) edition (Oxford University Press, 1902). In addition to the authors mentioned in the text and in the Bibliography, I am deeply indebted to Professor H. J. Paton for reading the entire manuscript and making many valuable suggestions, and to my wife for her assistance in correcting the proof and compiling the index. BIOGRAPHICAL NOTE In view of the abundance of biographies of Hume, I shall give only a short account of his life and personality. Hume was born at Edinburgh in 1711, of a poor but well- connected family of landed gentry, his father owning an estate called “Ninewells” near Berwick. He passed through the ordinary course of education at Edinburgh University and was destined by his family for the law. But, to use his own words, he “was seized very early with a passion for literature” and “found an insurmountable aversion to everything but the pursuits of philosophy and general learning”. Books on law were secretly neglected in favour of Cicero and Virgil. After an unsuccessful attempt to gratify his family by going into a business in Bristol in 1734, he went to France to study in a country retreat, adopting a plan of life to which he there¬ after consistently adhered, by which “he made a very rigid frugality supply his deficiency of fortune”. In France he com¬ posed the “Treatise of Human Nature” (between the ages of 23 and 26). He returned to London in 1737 and published the Treatise in 1738. According to Hume’s autobiography it “fell dead-born from the press”. Nevertheless, the sales were considerable, and though it was published in three separate successive volumes, the third volume (Book III, “Of Morals”) was accepted for publication in 1740. It also elicited a long and foolishly abusive review in the “History of the Works of the Learned”, which probably seriously upset Hume’s self-esteem, always distinctly tender in literary matters. The Treatise was published anonymously. 9 TO DAVID HUME * From 1737 to 1745 Hume lived with his mother and brother at Ninewells, recovering from the blow, re-leaming Greek, and writing and publishing a small volume of “Essays, Moral and Political”. In 1745 Hume made an unsuccessful bid for the vacant chair of “Ethics and pneumatic philosophy” at Edinburgh, and accepted a vexatious appointment as resident tutor to the young Marquis o'f Annandale. This appointment fortunately only lasted a year, and soon afterwards the Marquis was certified insane. In 1746 Hume had his only taste of military adventures; he accompanied General St. Clair as secretary on an abortive expedition directed against the coast of Brittany, and later, in the same capacity, on a diplomatic mission to Turin and Vienna. On the latter expedition he wore the uniform of an officer, in which, according to the Earl of Charlemont, he cut a very peculiar figure. The same authority gives us an account of Hume’s personal appearance, which, he adds, belied his real character to an unparalleled extent. “His face was broad and fat, his mouth wide, and without any other expression than that of imbecility. His eyes vacant and spiritless, and the corpulence of his whole person was far better fitted to communicate the idea of a turtle-eating Alderman, than of a refined philosopher. His speech, in English, was rendered ridiculous by the broadest Scotch accent, and his French was, if possible, still more laughable”.1 The “Enquiry concerning Human Understanding” was published in 1748, and the “Enquiry concerning the principles of Morals” in 1751. The latter he regarded as “incomparably the best” of all his works. Though more respectfully reviewed, in deference to Hume’s reputation as author of the Essays, these publications attracted little more attention than the Treatise. Hume was mortified but not discouraged. In 1752 Hume was appointed librarian to the Faculty of Advocates in Edinburgh and set up house with his sister in Edinburgh. He now turned his attention to History, a study facilitated by his access to the library. He wrote History back- 1Memoirs of Charlemont, I. 15.