A Friendship that Shaped Modern Thought: Dennis Rasmussen on David Hume and Adam Smith

Dennis Rasmussen, of Tufts, discusses his new book The Infidel and the Professor, which examines the friendship between David Hume and Adam Smith and how it changed our perception of truth and the world.

EW: Thanks so much for your time. You are a Political Science Professor at Tufts, in Boston. For those who are not too familiar with your background, what led you to explore the relationship between Hume and Smith so closely?

DR: Well, even before starting this book I’d worked on Hume and (especially) Smith for a long time. My first book centered on Smith’s response to Jean-Jacques Rousseau’s critique of commercial society, and my second book was a study of the Enlightenment that focused particularly on Hume, Smith, Montesquieu, and Voltaire. While doing the research for the latter I realized that no one had written a book on Hume and Smith’s personal or intellectual relationship, which was quite surprising.

I mean, it’s remarkable that two thinkers of this stature were best friends for most of their adult lives: Hume is widely regarded as the greatest philosopher ever to write in English, and Smith is almost certainly history’s most famous theorist of commercial society, or what we’d now call capitalism. It seemed like a story that absolutely had to be told, so I decided to try to tell it.

EW: The scene of this friendship is very important. That scene was 18th century Scotland shortly after Scotland helped form the United Kingdom. What was the political and religious landscape like there in which Hume and Smith lived and worked?

DR: All in all, their friendship took place during a period of political stability in Britain. They first met in 1749, a few years after the last of the major Jacobite uprisings, and Hume died in 1776, just as the conflict with the American colonies began to escalate. The only real political disturbances during this period were the Seven Years War with France and the “Wilkes and Liberty” riots of the late 1760s and early 1770s. But these episodes were fairly tame by most standards—certainly compared to the upheavals that opened and closed the century, those connected with the Glorious Revolution and the union of 1707, on the one hand, and the American and French Revolutions, on the other.

The religious landscape was in a bit more flux. The Church of Scotland was pretty rigid and repressive when Hume and Smith were young, but as the century wore on a group of progressive clergymen known as the Moderates—many of whom were Hume’s and Smith’s friends—began to preach a softer brand of Calvinism, emphasizing conduct over creed and insisting on the importance of tolerance. Still, their rival faction within the Kirk, known as the Popular Party or the High-Flyers, continued to make life uncomfortable for nonbelievers, including Hume (whom they tried to excommunicate).

St. Columbia Church in Edinburgh.

But the most remarkable aspect of their age was less the political or religious landscape than the intellectual landscape. Their age—the Scottish Enlightenment—was really one of history’s intellectual golden ages. Scotland began the 18th century as a poor, backward outpost on the fringe of Europe, but by the time Hume and Smith were writing in the middle of the century it had become a literary and cultural powerhouse—so much so that there’s even a recent bestselling book called How the Scots Invented the Modern World.

EW: Because people see economics as a more useful tool in today’s world, I suspect more people are familiar with the name Adam Smith than David Hume, so I wanted to focus on Hume at first. Hume writes his first book in 1739 when he is still in his twenties. What caused Hume to champion so much the cause of empiricism and reject thinking composed purely on logic and rationality?

DR: The cause of empiricism, or what Hume called “the experimental method,” was already well advanced by the time he wrote his Treatise of Human Nature. In fact, it was probably the dominant force in British philosophy since the time of John Locke, a couple of generations earlier. What was really novel about Hume’s book is that he pushed this method further, and drew out its consequences more uncompromisingly, than anyone ever had—and the consequences turned out to be revolutionary.

Hume concluded that if we rely entirely on experience—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. In fact, we can’t 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. But he doesn’t 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 universal doubt is simply unsustainable in the course of everyday life and, just as importantly, that we can attain a great deal of probable knowledge about the world and ourselves through the experimental method. 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.

EW: What implications did Hume’s empiricism have for religion and God?

DR: The Treatise includes very little explicit discussion of religion and God, but this very omission was enough 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’re on our own, with nothing beyond our frail and error-prone powers of understanding to guide us.

David Hume

EW: When he publishes Philosophical Essays, I think 8 or 9 years after his first work, he seems to stop self-censoring himself in many ways in regards to God and religion. What changed? Where was he drawing his confidence from? What was he risking?

DR: Yes, Hume had initially included in the Treatise a section casting doubt on the reality of miracles, and perhaps also one questioning the immortality of the soul, but he removed them in hopes of making the work somewhat less offensive to religious sensibilities. But in the Philosophical Essaysthe work now generally known as the First Enquiryhe did include his devastating attack on the idea of miracles, as well as a forceful critique of the foremost philosophical argument for God’s existence in his time (and perhaps ours as well), namely the argument from design.

As for why Hume decided to be more provocative in the latter work, one possibility—and here I’m drawing on a suggestion by an excellent Hume scholar, Sandy Stewart—is that he felt he had less to lose by this point. Though Hume tamed down the Treatise a bit in hopes of rendering it less offensive, it still caused plenty of offense, and as a result he was denied a position as a professor of ethics at Edinburgh University. It was just a couple of years later that he published the First Enquiry. So one possibility is that he reasoned that if he was going to have a reputation for impiety, he might as well earn it.

EW: You write that Adam Smith was caught at Baliol reading works by Hume, considered to be heretical, and the book was seized. You state that we don’t know where Smith got this copy, but do we have any guesses how something like this would circulate? There was no Amazon.com or Barnes and Noble. The libraries at Oxford wouldn’t have this. How would someone like Smith, contemplating the ministry, come to be reading David Hume?

DR: Well, the Treatise was a published work, so it’s not like it circulated underground, like samizdat. Smith could have purchased it through a bookseller. But given that it sold so poorly, it’s an interesting question how Smith came to be aware of it. I think the likeliest conjecture is that he first read Hume’s Essays Moral and Political—which were far more popular—and then found his way from them back to the earlier Treatise. Either way, it makes for a wonderful scene: a young scholar comes across a scandalous book by his future best friend, is caught by his orthodox dons, and is reprimanded for it. Certainly this episode can’t have endeared his professors to him, or discouraged his interest in Hume’s thought.

EW: How did Smith and Hume meet?

DR: After leaving Oxford Smith went on to do some freelance lecturing in Edinburgh, and that’s almost certainly where and when they first met, probably in the autumn of 1749. (There’s no real record of it, but the circumstantial evidence is pretty strong.) Presumably Smith would have been eager to meet Hume, given his familiarity with Hume’s works and his interest in Hume’s ideas, and by this point they already had a number of mutual friends who could have facilitated a meeting. It’s also very possible that Hume attended some of Smith’s lectures. Smith moved to Glasgow to take up a professorship there only a little over a year later, but it didn’t take long for them to become fast friends.

EW: Adam Smith has two great works. The first is The Theory of Moral Sentiments. This was a real radical departure from past thought. Smith argues that what ought to be, or a morality, is not governed in a completely objective way but governed by empathy and our social nature. You write in the book: “Smith’s central argument in The Theory of Moral Sentiments is that the sentiments of an impartial spectator are what set the ultimate moral standard: actions and character traits that would earn such a spectator’s approval are morally right and those that would earn his or her disapproval are morally wrong.” To give an example, we could say that for society to advance, we can’t go around killing each other, and so moral sentiment places enormous pressure on us not to kill, which is what makes it immoral rather than an objective pre-determined morality. How much does Smith draw from Hume in making his case and where does he depart from Hume’s philosophy?

DR: Virtually the whole of The Theory of Moral Sentiments shows unmistakable signs of Hume’s influence, down to the very examples that Smith uses. And the similarities between their moral theories are both broad and deep: both view morality as an eminently practical and human phenomenon, rather than one based on any kind of sacred, mysterious, or otherworldly authority; both hold that morality derives from human sentiments rather than reason; and both posit that right and wrong are established by the sentiments that we feel when we adopt the proper perspective, one that corrects for personal biases and misinformation.

Adam Smith

But Smith almost never simply adopted Hume’s views wholesale; on the contrary, he modified almost everything he touched. In the book I look at four major topics on which Smith deviated from Hume’s moral theory: the nature of sympathy, the role of utility, the foundation of justice, and the effects of religion. In most of these cases, Smith’s views are more nuanced, and arguably more sophisticated, than Hume’s—which will be surprising to many, since for much of the 20th century Smith’s philosophical writings were deemed to be little more than a series of footnotes to Hume’s.

EW: In 1776 when Smith writes The Wealth of Nations, his thinking had evolved somewhat from Hume’s. What other influences were filling in gaps for Smith?

DR: That’s a good question, and one that’s hard to answer with much certainty or comprehensiveness. Smith learned a great deal about political economy from a variety of sources in addition to Hume, including his teacher at Glasgow, Francis Hutcheson, French economists like Turgot and Quesnay, and surely many others—he was nothing if not an eclectic. Many of his conclusions were also simply derived from his own impressively wide-ranging research and observations.

One point that I emphasize in the book is that Smith expressed far more reservations or worries about commercial society than might be expected, given his reputation. My students are always struck by this—that Smith, who is often hailed as the founding father of capitalism, was in fact far less uniformly positive about commercial society than Hume was.

EW: Your study of a great and productive friendship between these two men reminded me of a book by Joshua Wolf Shenk called Powers of Two, about how creativity flourishes in pairs. I don’t know if you’ve read that, but had Smith not had Hume’s friendship would we have The Wealth of Nations at all? Is it more fair to say that David Hume and Adam Smith are jointly responsible for the advent of modern capitalism (or at least study of it) rather than only Smith as is commonly believed?

DR: Even I wouldn’t go so far as to say that Hume and Smith alone were responsible for the advent of modern capitalism, or the study of it—as important and influential as their contributions undoubtedly were. There were just too many thinkers in too many places who contributed to a change of that magnitude. But your broader point is exactly right: just as Smith’s contributions to moral philosophy have been unduly neglected in favor of Hume’s, Hume’s contributions to political economy have been unduly neglected in favor of Smith’s.

As an economist Hume has long been regarded as a minor predecessor of Smith, insofar as he’s taken notice of at all, but in fact he argued for free trade and stressed the moral, social, and political benefits of commerce several decades before The Wealth of Nations appeared. Hume’s essay “Of Luxury” (later retitled “Of Refinement in the Arts”) is one of the most forceful, comprehensive, yet succinct defenses of the modern, liberal, commercial order ever written.

EW: The book is very fascinating. Thank you for taking some time to talk to us about it.