David Hume
Based on Wikipedia: David Hume
The Philosopher Who Woke Kant from His Slumber
Immanuel Kant, perhaps the most influential philosopher of the modern era, credited one man with shocking him out of his intellectual complacency. That man was David Hume, a portly Scottish thinker with a fondness for good port and cheese who systematically dismantled nearly everything his contemporaries believed about knowledge, causation, morality, and the self.
Hume didn't just poke holes in existing philosophy. He demonstrated that the very foundations of human reasoning—our belief that the future will resemble the past, our conviction that one event causes another—rest on nothing more solid than mental habit.
This was not a minor adjustment to philosophical thinking. It was an earthquake.
Edinburgh's Precocious Son
David Hume was born on May 7, 1711, in a tenement on Edinburgh's Lawnmarket—though at birth his name was spelled "Home," the traditional Scottish way. He later changed the spelling to "Hume" because the English, who pronounced "Home" as it looks rather than rhyming it with "room," couldn't figure out what to call him.
His father, a lawyer, died when David was just two years old. His mother Catherine never remarried, raising David, his older brother, and their sister on her own. The family had noble ancestry but limited means. As a younger son, David had "little patrimony to live on"—a polite way of saying he was genteel but broke.
What he lacked in inheritance, he made up for in intellectual precocity. Hume enrolled at the University of Edinburgh at age twelve—possibly as young as ten—when fourteen was considered the normal starting age. His family expected him to become a lawyer, following his late father's profession. Hume had other ideas.
In his own words, he developed "an insurmountable aversion to everything but the pursuits of Philosophy and general Learning." While his family believed he was studying legal texts by Voet and Vinnius, he was secretly devouring Cicero and Virgil. He held his professors in low regard, telling a friend that "there is nothing to be learnt from a Professor, which is not to be met with in Books." He never bothered to graduate.
The Disease of the Learned
Around age eighteen, something happened to Hume—a philosophical revelation he called "a new Scene of Thought" that inspired him "to throw up every other Pleasure or Business to apply entirely to it." He never explained exactly what this breakthrough was, leaving scholars to speculate for centuries. One prominent theory suggests he realized that Francis Hutcheson's ideas about moral sense could explain how we actually develop our understanding of right and wrong.
Whatever the revelation was, it consumed him. Hume threw himself into a decade-long program of intensive reading and writing. The intensity nearly destroyed him.
First came what he called a "coldness," lasting about nine months, which he attributed to a "Laziness of Temper." Then scurvy spots broke out on his fingers. His physician diagnosed him with the "Disease of the Learned"—a contemporary term for the physical breakdown that sometimes afflicted intellectuals who spent too much time thinking and too little time eating, exercising, or going outside.
The prescribed treatment was remarkable: bitter tonics, anti-hysteric pills, and a pint of claret wine daily. Hume also decided he needed a more active life. His health improved, though in 1731 he developed a ravenous appetite and heart palpitations. The man who had been "tall, lean and raw-bon'd" transformed into someone "sturdy, robust and healthful-like."
Indeed, Hume would become famous for his considerable girth and his love of fine food and drink. He often used port and cheese as metaphors in his philosophical writings—perhaps the only philosopher to do so.
Writing a Masterpiece Nobody Read
By age twenty-five, Hume had no income, no profession, and no prospects. So he did what impoverished young men of his era often did: he became a merchant's assistant, leaving Scotland for Bristol, England. From there he traveled to La Flèche in the Anjou region of France, where he found something precious—access to the extensive library of the Jesuit college there, and frequent conversations with its learned residents.
Over four years, Hume poured everything he had into his first major work: A Treatise of Human Nature, subtitled "Being an Attempt to Introduce the Experimental Method of Reasoning into Moral Subjects." He was twenty-three when he began and twenty-eight when he finished.
The book was a complete failure.
Hume later lamented that it "fell dead-born from the press." British critics dismissed it as "abstract and unintelligible." Having spent most of his meager savings during those four years of writing, Hume resolved to practice "very rigid frugality" to preserve his independence while he figured out what to do next.
Yet in a letter, he revealed his resilient temperament: "Being naturally of a cheerful and sanguine temper, I soon recovered from the blow." He tried publishing a shorter summary of the Treatise's main ideas, hoping a more accessible version might find an audience. It didn't help much.
Here is the great irony of Hume's career: the book he considered a youthful embarrassment, asking contemporaries to judge him only on his later works, is today considered one of the most important texts in the history of Western philosophy. Scholars now agree that Hume's most distinctive and influential arguments appear in their most powerful form in this work he tried to disown.
The Problem of Induction
What made the Treatise so revolutionary? To understand this, we need to grasp what Hume was arguing against.
Before Hume, most philosophers believed that human reason could discover fundamental truths about reality. They thought we could work out, through pure logic, how the world must be. This approach—called rationalism—had champions like René Descartes, who tried to rebuild all of knowledge on the foundation of logical certainty.
Hume sided with the empiricists—thinkers like John Locke and George Berkeley who argued that all human knowledge comes from experience. We don't have innate ideas implanted in our minds at birth. Everything we know, we learned by seeing, hearing, touching, tasting, or smelling the world around us.
But Hume pushed empiricism further than anyone had before, and what he found was disturbing.
Consider causation. You see one billiard ball strike another, and the second ball moves. You naturally think the first ball caused the second to move. But what did you actually perceive? Hume pointed out that you never directly observe causation itself. You see one event, then another event. You see the "constant conjunction" of these events—they always seem to happen together. But the causal connection between them? That's invisible.
Your belief that striking the ball caused it to move isn't based on observing causation. It's based on habit. You've seen similar sequences many times, so your mind automatically expects one event to follow another. Custom and mental habit, not rational insight, create our belief in cause and effect.
This leads to what philosophers call "the problem of induction." Every day, you make predictions about the future based on the past. The sun has risen every morning of your life, so you expect it to rise tomorrow. But what justifies this inference? Only the assumption that the future will resemble the past.
And how do you know the future will resemble the past? Because it always has before.
Do you see the problem? You're using the principle that the future resembles the past to prove that the future will resemble the past. It's circular. There's no way to rationally justify our most basic form of reasoning about the world.
This doesn't mean Hume thought we should stop making predictions or believing in causation. We can't help it—our minds are built that way. But he wanted us to recognize that these beliefs rest on psychological habit, not rational proof.
Reason as the Slave of the Passions
Hume didn't stop at dismantling our beliefs about the external world. He turned his skeptical eye inward, toward human motivation and morality.
The conventional view, which Hume attacked, was that reason should govern our desires and actions. A good person, on this view, uses rational reflection to determine what's right and then controls their emotions accordingly. Passion and desire were seen as dangerous forces that reason needed to master.
Hume inverted this hierarchy completely. "Reason is, and ought only to be the slave of the passions," he declared. Reason alone cannot motivate action. It can tell you that if you want coffee, there's a café around the corner. But it cannot make you want coffee in the first place. All motivation originates in desire, emotion, passion—what Hume called sentiment.
The same applies to morality. We don't figure out what's right through abstract reasoning. We feel it. Moral judgments arise from moral sentiments—feelings of approval and disapproval, sympathy and disgust. Ethics is fundamentally about emotion, not logic.
This made Hume one of the earliest sentimentalists in moral philosophy, placing him in opposition to rationalists who believed moral truths could be discovered through pure reason. It also led him to formulate what's now called the "is-ought problem" or "Hume's guillotine": you cannot derive a statement about what ought to be done purely from statements about what is the case. Facts alone don't generate moral obligations.
The Bundle Theory of Self
Perhaps Hume's most unsettling argument concerns personal identity—the self.
When you introspect, when you try to observe your own mind, what do you actually find? You experience thoughts, feelings, perceptions, memories. But do you ever perceive a "self" that has these experiences? Hume argued that you don't. You never catch yourself without some perception or other. You never observe the observer.
This led Hume to a radical conclusion: the self doesn't exist as a unified, continuous thing. What we call "I" is nothing more than a bundle of perceptions—a constantly changing collection of experiences loosely connected by memory and imagination. There's no underlying substance, no soul, no permanent self that persists through time. Just the flow of experience.
This "bundle theory" of personal identity remains influential and controversial today, with implications for questions ranging from personal responsibility to the ethics of human enhancement.
Compatibility in a Deterministic Universe
What about free will? If all events are caused by prior events, stretching back infinitely, how can human choices be free?
Many philosophers saw determinism—the view that every event is caused by preceding events according to natural laws—as incompatible with free will. If your choices are determined by prior causes, they're not really your choices. You couldn't have done otherwise.
Hume disagreed. He developed what's now called compatibilism: the view that free will and determinism can coexist. What makes an action free, Hume argued, isn't that it's uncaused. It's that it flows from your own desires and character rather than external compulsion. You're free when you do what you want to do. The fact that your wants themselves have causes doesn't change this.
Consider: would you feel more free if your actions had no causes at all—if they were random? Probably not. We want our choices to reflect who we are, to express our character and values. That's perfectly compatible with those choices being caused by that character.
The Troublesome Atheist
Hume's religious views caused him endless trouble during his lifetime. He was never able to secure a university position, despite his growing fame, because ministers and religious authorities considered him an atheist and worked to block his appointments.
When he applied for the Chair of Pneumatics and Moral Philosophy at the University of Edinburgh in 1744, the position went to someone else after Edinburgh ministers petitioned the town council against Hume. The same thing happened when he was considered for a philosophy chair at the University of Glasgow. Even his friend Adam Smith, who had vacated that chair, opposed Hume's appointment, fearing the public backlash.
In 1761, the Catholic Church placed all of Hume's works on the Index Librorum Prohibitorum—the list of books Catholics were forbidden to read.
What were these dangerous religious views? Hume attacked the argument from design—the claim that the order and complexity of nature prove the existence of an intelligent creator. He also wrote devastating critiques of belief in miracles. A miracle, by definition, is a violation of natural law. But our evidence for natural laws is vast—the accumulated experience of all humanity. Our evidence for any particular miracle is usually just testimony from a few people. Rational calculation, Hume argued, should almost always favor the natural explanation.
In the 1750s, Hume's friends had to work to prevent him from being tried for heresy in an ecclesiastical court. He escaped by pointing out that as he wasn't a member of the Established Church, the court had no jurisdiction over him.
Success as Historian and Essayist
If Hume failed as a philosopher in his own time, he succeeded spectacularly as a historian and essayist.
In 1752, despite the controversies surrounding him, the Faculty of Advocates in Edinburgh hired him as their librarian. The position paid almost nothing, but it gave him something more valuable: "the command of a large library." With this resource, he embarked on his most ambitious project.
Over fifteen years, Hume wrote The History of England, a massive six-volume work spanning from Julius Caesar's invasion to the Glorious Revolution of 1688. It exceeded a million words. And unlike the Treatise, it was an immediate success—a bestseller that made Hume famous and financially comfortable.
For over sixty years, Hume's History was the definitive account of English history. He described his "love for literary fame" as his "ruling passion," and this work satisfied it completely.
Meanwhile, his essays on politics, economics, and literature found appreciative readers. His economic writings influenced Adam Smith and helped establish the intellectual foundations of classical economics. Hume corresponded with major figures across Europe and was welcomed in the salons of Paris, where French intellectuals celebrated him as a leading light of the Enlightenment.
Tutoring Lunatics and Befriending Rousseau
Hume's life wasn't all philosophical breakthroughs and library research. He had his share of peculiar employment.
In 1745, during the Jacobite risings that threatened to restore the Stuart monarchy, Hume took a job tutoring the Marquess of Annandale. It ended disastrously after about a year. The Marquess couldn't follow Hume's lectures, his father saw no need for philosophy, and on a personal level, the Marquess found Hume's eating habits bizarre. This was probably the beginning of Hume's reputation as a prodigious eater.
From 1746, Hume spent three years as secretary to General James St Clair, accompanying him on diplomatic missions to Turin and Vienna. The comfortable living took its toll: "the good table of the General and the prolonged inactive life had done their work," leaving Hume "a man of tremendous bulk."
From 1763 to 1765, Hume served at the British embassy in Paris, where he became a celebrity in French intellectual circles. He met philosophers, scientists, and socialites, though he sometimes missed "the plain roughness of The Poker Club of Edinburgh."
His most famous Parisian connection proved disastrous. In 1766, Hume accompanied the philosopher Jean-Jacques Rousseau back to England. Rousseau, brilliant but paranoid, soon convinced himself that Hume was conspiring against him. The two had a spectacular public falling-out that worried Hume so much about his reputation that he published an account of the quarrel to defend himself.
A Controversial Discovery
In 2014, an academic at Cambridge discovered a previously unknown letter that revealed an uncomfortable fact about Hume. In March 1766, Hume wrote to his patron Lord Hertford about a business proposition: several English gentlemen wanted Hume to help them acquire a half-share in slave plantations in Grenada, which Britain had recently acquired from France.
Whether Hume followed through on this proposal is unknown. But the letter reminds us that even the greatest minds of the Enlightenment operated within—and sometimes participated in—the moral blind spots of their era.
The Legacy of Doubt
David Hume died on August 25, 1776, at age sixty-five, having shaped philosophy in ways that persist to this day.
His skeptical arguments about causation and induction influenced logical positivism, the philosophy of science, and cognitive science. His moral philosophy shaped utilitarianism and contemporary ethics. His arguments about religion remain central to philosophy of religion. His writings on economics helped establish that field as a discipline.
And of course, he woke Kant from his dogmatic slumbers. Kant's entire critical philosophy—his famous Critique of Pure Reason and its sequels—was developed partly in response to Hume's challenges. If you've ever struggled with Kant, you have Hume to thank.
But perhaps Hume's greatest legacy is methodological. He showed that we should follow arguments wherever they lead, even if the conclusions are uncomfortable. He demonstrated that common-sense beliefs—about causation, about the self, about morality—deserve the same scrutiny as abstract metaphysical claims.
The cheerful, corpulent Scot who loved port and cheese turned out to be the most dangerous skeptic in the history of philosophy. And philosophy has never been the same.