The Pursuit of Certainty. Shirley Robin Letwin

having once laid hold of a favourite principle, extends it “over the whole creation and reduces to it every phenomenon, though by the most violent and absurd reasoning.”¹ Philosophical devotion, he said, was like the enthusiasm of a poet, “the transitory effect of high spirits,”² as wed as of leisure, genius, and study. The philosopher “no sooner puts in his stake than he is transported”³ by those passions he himself condemned. While he reasons about life, “life is gone; and death, though perhaps they receive him differently, yet treats alike the fool and the philosopher.”⁴ His great philosophical endeavour no longer appeared to be quite so amiable or important an undertaking. Indeed, his devotion to philosophy looked much like any other fanaticism. He began to feel that by turning to philosophy, he had not after all exorcised the spirit of the Kirk.

      There were good reasons for this feeling. After he became disenchanted with his Church, his character and outlook did not change at once. The young philosopher reflecting on the Treatise could easily be recognized as a son of the Kirk. The letter he wrote to Dr. Cheyne shortly before leaving for France has a distinct air of piety about it, even of priggishness. He told the doctor how he had studied the “books of morality” by Cicero, Seneca, and Plutarch, how smitten he had been with “their beautiful representations of virtue and philosophy,” and how he had tried to improve his temper and will, fortifying himself with “reflections against death, and poverty, and shame, and pain, and all the other calamities of life.”⁵ He observed his ailments minutely, dosed himself meticulously, and took to riding because it was good for his health. When he wrote from France to a school friend, he supplied statistics—Rheims has 40,000 inhabitants, 30 families keep coaches. And for his “idle thoughts,” he offered a pompous dissertation on the differences between French and English manners. He was no longer a fierce Presbyterian, but he was not at all like the favourite of Parisian salons that he later became.

      Indeed the Treatise itself is very much the credo of a man who has found a faith to replace one he had lost. For the supreme philosopher, no less than a devout member of the Kirk, is obsessed, as Hume said, by a particular vision of truth, by the desire to demonstrate that it is the only truth, and that it can be reduced to some one or few principles. Even a philosopher who lets the reader see his perplexities is seduced by his own abstractions. Thus Hume, while he was composing his Treatise in La Flèche, was possessed by the philosophical enthusiasm. He proclaimed his to be the one real philosophy, a new revelation of the truth about human nature. His was a holy crusade against Satan, who had taken on the form of abstruse metaphysics, final causes, and substance, and his talisman against Satan was the “experimental method.” While exposing the true nature of human reason. Hume was as relentless as a pious Presbyterian denouncing an adulteress. Although his Treatise is remarkable for his willingness to let loose ends hang without attempting to tie them up, he did try to make a whole creed. The urge to do so, hardly compatible with the moral message of his philosophy, was part of his puritan heritage, which had taught him the habit of encompassing all that he thought, felt, and did in one creed. Even when he set out to destroy this habit, he used its methods; and it was not until he had thoroughly disengaged himself from it, that he came to see his devotion to philosophy as the old enthusiasm in another form.

      By the time he had recast the first book of the Treatise of Human Nature, eight years after it was published, he was ready to take leave of the philosophical mood altogether. He now modestly offered the world merely Philosophical Essays Concerning Human Understanding. The earlier work, “which pretended to innovate in all the sublimest parts of philosophy,” was, he declared, “a mistake in conduct.” “The positive air which prevails in that book, and which may be imputed to the ardour of youth, so much displeases me, that I have not the patience to review it.”¹ Hume, the man of moderation, was ready to take over. The Kirk’s influence had ready been undone, for he had come to accept the “whimsical condition of mankind.”

      The dispute between the dogmatists and the sceptics no longer seemed so profound. They disagreed really, he declared, only on the degrees of doubt and assurance that it is proper to indulge in:

      No philosophical Dogmatist denies that there are difficulties both with regard to the senses and to all science; and that these difficulties are in a regular, logical method, absolutely insolvable. No sceptic denies that we lie under an absolute necessity, notwithstanding these difficulties, of thinking, and believing, and reasoning with regard to all kind of subjects, and even of frequently assenting with confidence and security.

      The difference was only one of emphasis—“The Sceptic, from habit, caprice, or inclination insists most on difficulties; the Dogmatist, for like reasons, on the necessity.”¹ The problems of the sceptical philosopher were not unique to him, and what he taught was not all that extraordinary. He, too, was a dreamer, and when he awoke, he would be

      the first to join in the laugh against himself, and to confess, that all his objections are mere amusement, and can have no other tendency than to show the whimsical condition of mankind, who must act and reason and believe; tho they are not able by their most diligent inquiry to satisfy themselves concerning the foundations of these operations, or to remove the objections which may be raised against them.²

      Hume had learned to ridicule even his own pretensions. More and more, he came to hold the sentiments he expressed to a friend before leaving with General St. Clair’s expedition: “I set out next week, as fully convinced as Seneca of the vanity of the world, and the insufficiency of riches to render us happy. I wish you had a little more of the philosophy of that great man, and I a little more of his riches.”³

      In the Enquiries, he described philosophy not as the science of human nature, but as “the reflections of common life methodized and corrected.”⁴ Instead of displaying his confidence in the revolutionary truths that the experimental method would establish, he indulged in concessions to the “easy philosophy,” which any educated man could understand and read, and he disparaged “the mere philosopher” who “lives remote from communication with mankind and is wrapped up in principles and notions equally remote from their comprehension.” The most perfect character lay “between the two extremes of the mere ignorant and the mere philosphere.”⁵ He was critical of moralists who tried to reduce human phenomena to a single principle. His own aspirations had become much more humble—to enlarge the stock of knowledge “on subjects of unspeakable importance.” He would be happy if, “reasoning in this easy manner,” he could undermine “the foundations of an abstruse philosophy, which seems to have hitherto served only as a shelter to superstition, and a cover to absurdity and error.”¹

      Sceptical philosophy, he came to think, was not the whole truth, but in a more modest way useful. A small tincture of scepticism could soften the pride of men, by showing them that the few advantages they “have attained over their fellows, are but inconsiderable, if compared with the universal perplexity and confusion, which is inherent in human nature.” Philosophy was not so much a revelation as a means of tempering the boldness of men. The greater part of mankind, who “are apt to be affirmative and dogmatical in their opinions,” and eager to escape from any hestitation or perplexity, tend to oppose one belief by violent affirmations to the contrary. But reflection on the infirmities of the human mind might “inspire them with more modesty and reserve, and diminish their fond opinion of themselves, and their prejudice against antagonists.”²

      Hume became less interested in metaphysical intricacies, and more anxious to press the moral of his philosophy, that the human condition allowed for no absolute purity, that men had better resign themselves to a measure of uncertainty and confusion, and a mixture of good and evil, true and false. All that he wrote after the Treatise was animated by the sentiment with which he ended his History of Natural Religion:

      … good and ill are universally intermingled and confounded: happiness and misery, wisdom and folly, virtue and vice. Nothing is pure and entirely of a piece. All advantages are attended with disadvantages. An universal compensation prevails in all conditions of being and existence. And it is not possible for us, by our most chimerical wishes to form the idea of a station or situation altogether desirable. The draughts of life, according to the poet’s fiction, are always mixed from the vessels of