🏴󠁧󠁢󠁳󠁣󠁴󠁿David
Hume

David Hume was born on May 7, 1711, in Edinburgh, Scotland, the second son of a modest Borders gentry family. His father died when he was two, and he was raised by his mother, who reportedly remarked that Davie was "uncommon wakeminded" — unusually bright. He entered the University of Edinburgh at around twelve, as was customary, and left without a degree at fifteen, as was also customary. What was not customary was the intellectual passion that consumed him during the years that followed. Hume attempted briefly to study law, then to work as a merchant's clerk in Bristol, then simply to read and think. Between the ages of twenty-three and twenty-six, living on a tiny allowance in La Flèche, France — the same town where Descartes had attended school — he wrote A Treatise of Human Nature, the most ambitious and radical work of philosophy composed in the English language.

The Treatise, published in 1739 and 1740, opens with a rigorous empiricist programme. Hume proposes to apply to the study of human nature the same experimental method that Newton had applied to nature. All our mental contents — what Hume calls perceptions — are either impressions (vivid sensory experiences) or ideas (fainter copies of impressions stored in memory and imagination). There are no innate ideas; every concept must ultimately be traceable to some original impression. This principle becomes the razor Hume uses to destroy the metaphysical pretensions of his predecessors. What impression could ground the concept of substance? Of the self? Of God? Of causation? In each case, Hume's analysis is devastating.

The problem of induction is Hume's most consequential and disturbing argument. We routinely infer from past experience to future events: the sun has always risen before, so it will rise tomorrow; fire has always been hot, so it will be hot again. But what justifies this inference? Not logic — there is no logical contradiction in imagining the sun failing to rise or fire being cold. And not experience — to use past experience to justify trusting past experience would be circular. The justification for induction cannot itself be inductive without vicious circularity, and it cannot be deductive because inductive conclusions are not logically guaranteed by their premises. Hume concluded that our confidence in inductive reasoning rests not on rational justification but on custom and habit: the mind is simply wired to expect the future to resemble the past. This was not merely a philosophical puzzle; it was a direct challenge to the foundations of empirical science, and philosophers and scientists have been trying to answer it ever since.

His analysis of causation deepens the crisis. We never actually perceive a necessary connection between cause and effect. We see one billiard ball strike another and the second move, but we do not see the causing — the supposed necessary transfer of force. We only observe constant conjunction: whenever A, then B. The impression of necessary connection comes not from the external world but from the mind itself: after observing constant conjunction repeatedly, the mind develops a habitual expectation, and it is this internal feeling of expectation that we project onto the external world and call causation. Hume's causation is thus psychological, not metaphysical. This argument shattered the Newtonian picture of a world of iron causal laws and replaced it with a world of regular patterns and mental habits — a more modest but more honest account that shaped positivism, pragmatism, and the philosophy of science for the next three centuries.

The Treatise fell, as Hume recalled with wry self-deprecation, "dead-born from the press." He rewrote its central ideas in the more accessible Enquiries Concerning Human Understanding (1748) and Concerning the Principles of Morals (1751). In moral philosophy, Hume argued against the rationalist view that reason alone can motivate moral action: "Reason is, and ought only to be the slave of the passions." Moral judgments are expressions of sentiment, not deductions from reason. We approve of actions that promote happiness and disapprove of those that cause suffering — not because reason tells us to, but because we are constituted to feel sympathy. This sentimentalist moral theory was a major influence on Adam Smith, who was Hume's close friend, and on modern metaethics.

In religion, Hume was the eighteenth century's most formidable critic. His Dialogues Concerning Natural Religion, completed by 1751 but prudently not published until after his death in 1779, dismantled the argument from design with devastating precision. Even if the universe shows order analogous to human artifacts, he argued, we cannot infer that it had a designer analogous to a human designer — we have no experience of universes being made and no basis for comparison. The universe might have arisen from any number of causes, including purely natural ones. His essay On Miracles argued that no human testimony can be sufficient to establish a miracle, because the evidence against any violation of the laws of nature will always outweigh the evidence of human testimony, which is notoriously unreliable. These arguments effectively closed the door on natural theology as a serious intellectual enterprise.

Hume spent his later years in Edinburgh and Paris, where he served as secretary to the British Embassy and became a celebrity of the French Enlightenment — the philosophes adored him. He was celebrated for his affable, witty character as much as for his philosophy. He died of intestinal cancer on August 25, 1776, with the equanimity he had recommended in his philosophy, reportedly joking on his deathbed that he could not think of a good enough excuse to offer Charon to delay his passage across the Styx. His posthumous reputation has only grown. Kant credited him with provoking the critical philosophy. Karl Popper's falsificationism was a direct response to Hume's problem of induction. Bertrand Russell called him the greatest philosopher who ever wrote in the English language — a verdict that few who have wrestled seriously with the Treatise would dismiss.