empiricism
Empiricism is the idea that we learn about the world mainly by experiencing it — through seeing, hearing, touching, and testing — rather than by reasoning it out from pure thought. Picture a child who learns that fire is hot not by deducing it, but by getting too close once and never forgetting. For the empiricist, that is the model for all real knowledge: look, try, and let the evidence teach you.
Its boldest champions were the British thinkers John Locke and David Hume in the 1600s and 1700s. Locke famously imagined the newborn mind as a blank slate — in Latin, a tabula rasa — with no ideas written on it yet. Everything we come to know, he argued, gets written there by experience. Hume pushed harder still, insisting that even our deepest convictions about cause and effect are really just habits built from watching the same things happen over and over.
It is easy to misread empiricism as anti-thinking, but that misses the point. Empiricists prize reasoning — they simply insist that reasoning must start from what the senses deliver, not float free of it. This is the same instinct that powers modern science: a beautiful theory still has to face the evidence, and if the world says no, the theory loses.
Tell a true empiricist "all swans are white," and they'll answer: only until we find a black one — and in Australia, we did.
The word comes from the Greek empeiria, meaning "experience"; the same root gave us "empirical." Empiricism is the classic counterpart to rationalism, which holds that some important knowledge comes from reason alone, independent of the senses.