PreSocratic

The pre-Socratics is a term used to describe a broad group of early Greek philosophers who were active roughly from the late 7th century to the early 5th century BCE. They focused on natural philosophy, asking foundational questions about the cosmos, the origin of the universe, and the nature of change and matter. Their work marked a shift from mythological explanations toward rational inquiry and observation.

Among them were the Milesian philosophers, Thales, Anaximander, and Anaximenes, who sought a single underlying principle or arche (such as water, the boundless, or air) that explains all natural phenomena. Later figures such as Heraclitus emphasized constant change and fire as a fundamental principle, while Parmenides argued for the unity and immutability of Being, countering the reality of change with his famous paradoxes in the Eleatic school. The movement also included the Pythagoreans, who connected numbers, harmony, and mathematical order to the structure of reality, and the atomists, Democritus and Leucippus, who proposed that matter consists of indivisible particles in empty space. Anaxagoras introduced the notion of Nous (mind or intellect) organizing matter. Zeno of Elea, a student of Parmenides, is known for his paradoxes that challenge the possibility of plurality and motion.

The pre-Socratics did not form a single school or system, but they collectively advanced critical methods, including rational argument, careful observation, and a willingness to test explanations against experience. Their legacy influenced later Greek philosophy, especially Socrates, Plato, and Aristotle, and contributed to the development of metaphysics, science, and the philosophy of nature. The term is a modern scholarly designation rather than a label these thinkers used for themselves.