ἐμπειρία

Empeiría in Greek means experience, from empeiros (experienced, skilled in), which derives from en (in) and peira (trial, attempt). The Empirikoi were a school of physicians in ancient Greece — Philinus of Cos, around 250 BCE, argued that medical knowledge should come from direct observation and clinical experience, not from theoretical systems. They opposed the Dogmatikoi (Rationalists), who reasoned from first principles about unseen causes of disease.

The philosophical meaning crystallized in seventeenth-century England. John Locke's Essay Concerning Human Understanding (1689) argued that the mind at birth is a tabula rasa — a blank slate. All knowledge comes from sensation and reflection. There are no innate ideas. George Berkeley and David Hume pushed empiricism further. Hume's conclusion was radical: even causation — the idea that one thing causes another — is just a habit of association formed by repeated experience.

The word 'empirical' became the standard adjective of science. Empirical evidence. Empirical method. Empirical validation. Francis Bacon had championed inductive reasoning from observation in the early 1600s, and the Royal Society of London, founded in 1660, adopted nullius in verba (take nobody's word for it) as its motto. The empirical tradition became the epistemological foundation of the scientific revolution.

Modern science is empiricist in practice even when individual scientists are not aware of the philosophical tradition. The controlled experiment, the double-blind trial, the requirement for reproducibility — all are descendants of the Greek physicians who said: watch what happens, then decide what you know.