Aristotelians
Plato's most brilliant student spent twenty years in the Academy and walked out the door pointing the other way. Where Plato put the truest reality in a separate realm of perfect Forms beyond the world, Aristotle put it here, in ordinary things: known by looking at them, sorting them into kinds, and finding the purpose built into each. That conviction, that reality is the world itself and the way to understand it is to study it, became the most influential program in the history of thought. It nearly died when his books vanished from western Europe, was rescued and pushed forward by the Islamic and Jewish worlds, came roaring back into Europe in a flood of translations that the Church tried to ban, got fused with Christianity into a system that stood for four centuries, and was finally overthrown by the scientists who learned how to look from Aristotle and then caught him being wrong. This is the afterlife of the man the Middle Ages called, simply, the Philosopher.
