Aristotle

Aristotle was the first great systematizer of knowledge in the Western world, creating foundational frameworks for logic, biology, physics, metaphysics, and ethics. While many of his physical theories (like geocentrism) were later overturned, his empirical approach—emphasizing observation and classification—was revolutionary. He pioneered zoology, dissecting and classifying hundreds of species. His system of deductive logic, particularly the syllogism, remained the dominant form of reasoning for two millennia.

He established the Lyceum and his works became the core of the medieval university curriculum. His influence, though often a foil for later scientists like Galileo, was immense; the Scientific Revolution was in many ways a reaction against and a movement beyond Aristotelian science. His role was in establishing the very practice of organized, rational inquiry into the natural world.