CHAPTER 1
THE CHEERFUL SKEPTIC
(1711–1749)
DAVID HUME IS, it seems fair to say, among the most loved of philosophers, widely cherished for his affable personality, his clearheadedness, and his unflinching yet humane world-view. A recent survey of thousands of academic philosophers around the world found that more identified themselves with Hume than with any other figure in the history of philosophy.1 During his own time too Hume was adored by virtually everyone who knew him well. He was a favorite among the Edinburgh literati, even the ministers, and the high society of Paris bestowed on him the honorific le bon David. Outside of these relatively confined circles, however, Hume’s controversial views earned him plenty of fierce detractors. He told a friend in 1764, “I do not believe there is one Englishman in fifty, who, if he heard that I broke my Neck last night, woud not be rejoic’d with it. Some hate me because I am not a Tory, some because I am not a Whig, some because I am not a Christian, and all because I am a Scotsman.”2 Even in our own more hardened age, and notwithstanding all of Hume’s engaging good humor, the seemingly relentless nature of his skepticism leaves many readers disconcerted, even alarmed. Isaiah Berlin spoke for many when he opined that “no man has influenced the history of philosophical thought to a deeper and more disturbing degree.”3
Hume was born on April 26, 1711, the third and final child of a relatively prosperous farmer and country laird.4 The Home family—Hume changed the spelling of his last name to match the pronunciation while in England in 1734—lived at Ninewells, south of Edinburgh, near the border with England. Hume was still a small child when his father, Joseph, died of tuberculosis, so he was largely raised by his mother, née Katherine Falconer, who was the daughter of one of the leading judges in Scotland. As the oldest son Hume’s brother, John, eventually inherited the family estate. Like Hume himself his sister, named Katherine like their mother, never married, and so she remained attached to her brothers throughout their lives; she would become an integral part of Hume’s household in his later years.
Hume entered Edinburgh University at the decidedly tender age of ten.5 The universities of eighteenth-century Scotland were in many respects more reminiscent of modern boarding schools for high school students than today’s colleges and universities, but Hume’s entrance was early even by the standards of the day, likely because he began at the same time as his older brother. At Edinburgh Hume studied Latin, Greek, logic, metaphysics, and “natural philosophy,” or natural science as we would call it today. He would have been able to attend public lecture series on moral philosophy and “pneumatics” (i.e., philosophy of mind) as well, though we do not know if he did. All of the courses were thoroughly infused with religious precepts for the edification of the young students. Judging from his later comments Hume seems to have found his university education emphatically lacking in interest and usefulness, with the possible exception of the natural philosophy course. In 1735 he counseled a young friend that “there is nothing to be learnt from a Professor, which is not to be met with in Books.… I see no reason why we shou’d either go to an University, more than to any other place, or ever trouble ourselves about the Learning or Capacity of the Professor.”6 Hume attended classes for four years without, however, taking a degree—a fairly common practice at the time.
After leaving the university Hume’s real education began. He spent most of the next eight years—ages fourteen to twenty-two—in independent study, immersing himself in works of philosophy and literature. He did attend law lectures at the university for a time, but he found the subject less than congenial. Hume reports in My Own Life that “my studious disposition, my sobriety, and my industry, gave my family a notion that the law was a proper profession for me; but I found an insurmountable aversion to every thing but the pursuits of philosophy and general learning; and while they fancied I was poring upon Voet and Vinnius”—that is, legal works—“Cicero and Virgil were the authors which I was secretly devouring.”7 The central role that friendship would come to play in Hume’s life too was evident quite early on: in his first extant letter, written when he was only sixteen, he declares that “the free Conversation of a friend is what I would preferr to any Entertainment.”8 During this period he continued to live with his family, mostly spending the winters in Edinburgh and the summers at Ninewells.
Hume was, as far as we can tell, given a typical Christian upbringing in a God-fearing family. His mother, brother, and sister were all pious Presbyterians, and his uncle was a minister at the local kirk in the village of Chirnside, which was strict enough to conduct heresy trials and put sinners in the pillory. As a boy Hume too was religious. He later recalled using the catalogue of vices in The Whole Duty of Man, a popular seventeenth-century devotional tract, to test his moral character. Among the breaches of duty highlighted in the text are “not assigning any set or solemn times for humiliation and confession, or too seldom”; “making pleasure, not health, the end of eating”; and “wasting the time or estate in good fellowship”—all injunctions that the adult Hume would find difficult to observe indeed.9 During his teenage years, however, doubts persistently crept into his mind. As he later told a friend, he began “with an anxious Search after Arguments, to confirm the common Opinion: Doubts stole in, dissipated, return’d, were again dissipated, return’d again.”10 Near the end of his life Hume disclosed to James Boswell that he “never had entertained any belief in Religion since he began to read Locke and Clarke.”11 In other words, Hume’s encounter with the defenses of theism in the works of John Locke and Samuel Clarke had the effect of undermining his faith rather than bolstering it. (He thereby unwittingly made good the quip of Clarke’s contemporary Anthony Collins that no one had doubted God’s existence until Clarke tried to prove it.)12
By the time of his eighteenth birthday Hume had determined what course he would pursue in life: “I cou’d think of no other way of pushing my Fortune in the World, but that of a Scholar & Philosopher.” Yet the road from his early studies to the (still early) writing of A Treatise of Human Nature was not an entirely straight one. After a period of intense, solitary reading Hume found himself suffering from a psychosomatic illness that his doctor dubbed “the Disease of the Learned.” Upon moderating the pace of his studies, spending more time in society, eating better, and taking some exercise—walking and riding virtually every day—his health began to improve. One result of this change in lifestyle was that Hume was transformed from a “tall, lean, & rawbon’d” youth into the “most sturdy, robust, healthful-like Fellow you have seen, with a ruddy Complexion & a chearful Countenance.”13 In the process of recovering from his malady Hume made a brief stab at a life of commerce, working as a merchant’s clerk in Bristol, but he soon found the post “totally unsuitable.”14 He seems to have been found equally unsuitable by his employer: he was fired for correcting his master’s grammar.
In September 1734 Hume departed for France with an eye to composing a projected work on the broad topic of human nature. After a brief period in Paris he spent a year in the university city of Rheims and then another two at La Flèche, a sleepy town in the Loire Valley whose Jesuit college was famous as the site of René Descartes’s education and was still, in the eighteenth century, a hotbed of the Cartesian philosophy that Hume was seeking to upend. The first two volumes of the Treatise, “Of the Understanding” and “Of the Passions,” were largely written during this three-year stay on the Continent. Filled with anticipation, Hume returned to London in September 1737 to publish the work, which finally appeared in January 1739. Rather naïvely expecting that a long, dense, difficult philosophical tome would produce an immediate revolution in thought, Hume was bound to be disappointed in the work’s reception. In My Own Life he lamented that it “fell dead-born from the press, without reaching such distinction, as even to excite a murmur among the zealots.”15 (The italicized phrase derives from Alexander Pope’s declaration that “All, all but Truth, drops dead-born from the Press, / Like the last Gazette, or the last address.”)16 The Treatise was reviewed a bit more often, and more favorably, than Hume’s lament suggests, but it is true that it did not sell particularly well. Soon after the work’s release Hume returned to Scotland and persevered in adding a third volume, “Of Morals,” which met with even greater public indifference when it was published in November 1740. While Hume’s first book failed to find much of an audience at the time, the intervening years have more than made up for this failing: contemporary philosophers are nearly unanimous in deeming the Treatise Hume’s philosophical masterpiece. In the nineteenth century Thomas Henry Huxley, aka “Darwin’s Bulldog,” went so far as to claim that “it is probably the most remarkable philosophical work, both intrinsically and in its effects upon the course of thought, that has ever been written.”17
For a first book by a young man still in his late twenties, the Treatise certainly did not lack for ambition. Hume’s stated goal was nothing less than to propound a new science of human nature that would in turn serve as the basis for every other branch of knowledge. He opens the work by bemoaning the “ignorance, which we still lie under in the most important questions, that can come before the tribunal of human reason,” and he proposes that the only effective strategy for remedying the deficiency is “to leave the tedious lingring method, which we have hitherto follow’d, and instead of taking now and then a castle or village on the frontier, to march up directly to the capital or center of these sciences, to human nature itself; which being once masters of, we may every where else hope for an easy victory.”18 Hume sought to erect his science of human nature using what he called, in the subtitle of the work, “the experimental method.” Whereas Descartes, for instance, had aimed to base his conclusions as much as possible on pure, abstract reason, Hume insisted that the “only solid foundation” for knowledge about human beings and the world around us is to be found in “experience and observation.”19 He was far from the first philosopher to propose relying on experience in this way—he himself names John Locke, the Third Earl of Shaftesbury, Bernard Mandeville, Francis Hutcheson, and Joseph Butler as his predecessors in this regard—but Hume sought to push this method further, and to draw out its consequences more uncompromisingly, than anyone ever had.20
The consequences turned out to be revolutionary. Hume concluded that if we rely entirely on experience—that is, if we reject the inflated, unwarranted faith in the powers of human reason that previous philosophers had shown—then we can know exceedingly little about the world or ourselves with absolute certainty. Indeed, we cannot even know that there is an external world, beyond our immediate senses, or that we are selves, meaning discrete individuals who persist stably over time. Pretty much the only things that we can know with certainty, according to Hume, are the propositions of mathematics (2 + 2 = 4) and pure logic (all bachelors are unmarried). However, he does not suggest that we should therefore live in a perpetual skeptical fog, constantly doubting everything that we see and think. On the contrary, he insists that human nature itself prevents this: universal doubt is simply unsustainable in the course of everyday life. Just as importantly, Hume allows that we can attain a great deal of probable knowledge about the world and ourselves through the experimental method—hence the possibility of formulating a new “science of man.” His most famous example is that of causation: even if abstract reason cannot demonstrate that one billiard ball striking another will produce movement—and it cannot—all of our past experience suggests that it will do so, and it would be foolish to disregard the guidance that experience provides. Hume’s stunning diminution of the role that reason plays in human life is thus matched by a great expansion of the roles played by custom, habit, the passions, and the imagination.
The Treatise includes very little explicit discussion of God or religion, but this very omission was sufficient to make the work scandalous: by exploring human nature in painstaking detail without appealing to any kind of higher power, Hume was implying that no such appeal is needed. Human beings are neither innately sinful nor created in God’s image, for Hume, but rather comparatively intelligent, if passion-driven, animals. Moreover, the idea that experience is the only reliable basis of knowledge suggests that we are on our own, with nothing beyond our frail and error-prone powers of understanding to guide us. That the work was irreligious in nature was not lost on Hume’s contemporaries, although it was originally intended to be still more so.21 The version that Hume penned in France had included a section casting doubt on the reality of miracles and perhaps also a section questioning the immortality of the soul.22 Fearing that these passages would “give too much Offence even as the World is dispos’d at present,” Hume decided that it would be worth his while to spend some time “castrating my Work, that is, cutting off its noble Parts, that is, endeavouring it shall give as little Offence as possible.” He declared that “this is a Piece of Cowardice, for which I blame myself.… But I was resolv’d not to be an Enthusiast, in Philosophy, while I was blaming other Enthusiasms.”23 While Hume would later lament that the work failed even to excite a murmur among the zealots, then, he had in fact taken some pains to prevent it from doing...