Empiricism is the view that what we know about the world — as opposed to what we can work out by pure logic — comes from experience. We are not born with knowledge of physics, or history, or even of the basic categories of space and time, hardwired into the mind; we acquire all such knowledge through perception, through the accumulation of sensory impressions that the mind organizes into concepts and beliefs. The mind, on the empiricist picture, begins as what John Locke called a “tabula rasa” — a blank slate on which experience writes. This seems, on its face, almost obvious. Where else would knowledge of the world come from? But the history of philosophy is largely the story of working out why this seemingly obvious view turns out to be philosophically treacherous, and what a consistent empiricism actually commits one to.
Francis Bacon, in the early 17th century, made the case for experience over authority in natural philosophy — his “Novum Organum” (1620) argued that the path to knowledge ran through careful observation and experiment, not through Aristotle. John Locke then provided the canonical philosophical statement of empiricism in his “Essay Concerning Human Understanding” (1689), arguing systematically against innate ideas and tracing all knowledge back to simple sensory impressions. George Berkeley took Locke’s premises further than Locke intended: if everything we know comes from experience, and experience is always experience of mental representations, then what grounds do we have for believing in a material world outside those representations? Berkeley’s startling answer was none — hence his idealism, the view that what exists is minds and their ideas. David Hume pressed the empiricist principle hardest of all. He asked what, from the empiricist standpoint, justified our belief in causation, in the persistence of physical objects, or in the continuing identity of the self — and found that nothing did. These beliefs were habits of mind, not knowledge. Hume’s empiricism thus arrived at a kind of systematic skepticism that has never been fully answered. John Stuart Mill extended the tradition into the 19th century, arguing that even the seemingly self-evident truths of mathematics were inductive generalizations from experience.
The philosophical significance of empiricism is inseparable from the rise of modern science. The insistence that claims about nature must answer to observation — rather than to authority, tradition, or a priori deduction — is the methodological core of the scientific revolution. In this sense, empiricism is not just a philosophical position but a cultural one: it is the epistemology of the laboratory, of the clinical trial, of the statistical survey. It places the locus of epistemic authority in the world rather than in the mind, in evidence rather than in intuition, in what can be tested rather than what seems necessarily true. These commitments are at the heart of the freethinking tradition, which has consistently appealed to experience over revelation.
The difficulty with empiricism is that, pressed to its limits, it seems to undermine more than religion. A strict empiricism cannot account for mathematics, for logic, for the universal and necessary truths that science itself depends on. We do not derive the laws of logic from sensory experience; we use them to interpret sensory experience. Hume’s problem of induction — the fact that no number of past observations logically guarantees anything about the future — has never received a fully satisfying solution. And the idea that sensory experience is a transparent window onto the world has been complicated by everything we have learned about perception, about cognitive bias, and about the theory-laden character of observation. The history of the concept is, in this sense, a story of deepening: empiricism is right about something fundamental, but what, exactly, it is right about has proven difficult to specify.
What empiricism represents, at its best, is an insistence on accountability to the world — a refusal to treat the products of pure thought, however compelling they feel, as automatically reliable guides to reality. That insistence remains indispensable.