Anaxagoras Born in Clazomenae, in Ionia, around 500 BCE, Anaxagoras was the first philosopher to bring the Ionian tradition to Athens, where he lived for some thirty years and became a friend and adviser of the statesman Pericles. His intellectual boldness cost him dearly: accused of impiety for holding that the Sun was not a god but an incandescent stone, he was put on trial and had to leave the city, taking refuge in Lampsacus. ...
Anaximander A fellow citizen and disciple of Thales of Miletus, Anaximander (c. 610–546 BCE) was one of the boldest minds of the Milesian school and perhaps the first thinker to write a prose treatise on nature. Tradition credits him with the pioneering use of the term arché (“principle”), as well as remarkable achievements: drawing the first map of the inhabited world and introducing the gnomon (sundial) into Greece. Dissatisfied with Thales’s water, Anaximander proposed as the principle the apeiron — the boundless, indeterminate, and imperishable. No particular element could give rise to all the others without being consumed by them; only something indefinite and inexhaustible could be the eternal source of everything. From the apeiron, eternal and divine, the opposites (hot and cold, wet and dry) separate out, and from this separation worlds are born — which, in due time, return to it. The only surviving verbatim fragment, transmitted by Simplicius, speaks of this cosmology in moral terms: things “pay one another penalty and retribution for their injustice, according to the order of time.” ...
Anaxímenes The third great name of the Milesian school, Anaximenes (c. 585–525 BCE) was a disciple of Anaximander. At first glance he took a step back, rejecting his master’s indeterminate apeiron and returning to a concrete element as the principle: air (aēr). But his choice carried a decisive advantage — air, being determinate, allowed him to explain how the single principle transforms into all things, something that neither Thales’s water nor the apeiron explained clearly. ...
Democritus Born in Abdera, in Thrace, and active around 430 BCE, Democritus was one of the most erudite minds of antiquity — he traveled widely and wrote on almost everything, though none of his works has reached us. Tradition nicknamed him “the laughing philosopher,” in contrast to the melancholy Heraclitus. Together with his teacher Leucippus, he is the founder of atomism, the first fully materialist and mechanistic philosophy in history. His thesis is as simple as it is audacious: reality reduces to two principles — atoms and the void. Atoms (from the Greek atomon, “indivisible”) are eternal, solid, imperceptible particles that differ only in shape, size, position, and arrangement. The void is the space in which they move. Everything that exists — things, the world, and even the soul (made of finer, subtler atoms) — results from the collisions and combinations of these atoms in eternal motion. In Democritus’s cosmos there is neither purpose nor ordering intelligence: everything is explained mechanically, by necessity. ...
Empedocles Empedocles (c. 494–434 BCE) was one of the most extraordinary figures of Greek philosophy: at once philosopher, physician, poet, orator, and political leader in his native city of Akragas, in Sicily. A legendary aura formed around him — he presented himself almost as a god among men, and tradition holds that he leapt into the crater of Mount Etna to confirm his divinity. He expounded his ideas in two poems, On Nature and Purifications. ...
Heraclitus Born in Ephesus, in Ionia, and active around 500 BCE, Heraclitus belonged to an ancient aristocratic family. Proud and solitary in temperament, he wrote in a style of enigmatic aphorisms that earned him, already in antiquity, the epithet “the Obscure.” Some 126 fragments survive — dense, paradoxical, and of extraordinary poetic force. His central intuition is that of universal becoming: nothing remains, everything transforms ceaselessly — “panta rhei,” “everything flows.” Hence his most famous image: one cannot step into the same river twice, for fresh waters are ever flowing upon those who enter it. As the symbol of this perpetual flux, Heraclitus chose fire as the principle (arché): reality is like a flame that endures precisely because it is always consuming and renewing itself. ...
Parmenides Born in Elea, a Greek colony in southern Italy, and active in the first half of the fifth century BCE, Parmenides is the founder of ontology — the inquiry into being as being — and the greatest figure of the so-called Eleatic school. He expounded his thought in a philosophical poem, On Nature, of which fragments survive: in it, a young man is carried in a chariot to a goddess who reveals the truth to him. ...
Pythagoras Born on the island of Samos around 570 BCE, Pythagoras emigrated to Croton, in southern Italy (Magna Graecia), where he founded a philosophical-religious community famous for its austere way of life, its rules of silence, and the secrecy of its teachings. Since he wrote nothing and his disciples attributed everything to the master, it is difficult to separate his ideas from those of the Pythagoreans who followed him; already in antiquity his figure blended with legend. ...
Thales of Miletus A philosopher from Miletus, in Ionia (in present-day Turkey), who lived around 624–546 BCE, Thales is considered the first philosopher of the Western tradition and was counted among the legendary Seven Sages of Greece. He left no writings; what we know comes from later reports, above all from Aristotle, who hailed him as the founder of this kind of inquiry (Metaphysics I, 3). Many stories gathered around his name: he is said to have predicted a solar eclipse, measured the height of the pyramids by their shadow, and, according to Aristotle, demonstrated the practical value of philosophy by foreseeing a good harvest and cornering the olive-press market. ...
Xenophanes of Colophon Itinerant Greek poet-philosopher. Traveled throughout the Greek world for decades singing his philosophical verses. Considered a precursor to the Eleatic School (influenced Parmenides). Notable for his critique of anthropomorphic religion and proto-epistemological observations. Key Concepts Critique of religious anthropomorphism: Homer and Hesiod attributed human crimes to the gods (theft, adultery, betrayal); the Ethiopians make their gods black and flat-nosed, the Thracians make theirs blonde and blue-eyed — if oxen and horses could paint gods, they would make them bovine and equine Philosophical monotheism: there is a single God, the greatest among gods and men, who resembles mortals in nothing — neither in body nor in thought; immobile, he governs all things by his thought Epistemology of moderate skepticism: the gods did not reveal everything to men from the beginning; mortals discover the best progressively — but no man attains total truth about the gods and the cosmos; even if one spoke the truth, one could not be certain Geology and fossils: found marine fossils on mountains and concluded that earth and sea alternate; used empirical observations to speculate about cosmic changes Influenced by Milesian School — naturalism and critique of myth Greek poetic tradition — uses philosophical hexameters and elegies Influenced Parmenides — monism and concept of the One Ancient Skepticism (through epistemological humility) Plato — critique of the representation of gods in Homer (Republic) Works Fragments in verse (elegies, silloi, didactic poem On Nature) preserved through citations by other authors. ...
Zeno of Elea Born in Elea, in southern Italy, and active in the mid-fifth century BCE, Zeno was the most celebrated disciple of Parmenides — according to Plato, he accompanied his master to Athens, where the two are said to have conversed with the young Socrates. Tradition also attributes to him a heroic end: tortured by a tyrant whose overthrow he was plotting, he is said to have preferred death to betrayal. He is remembered above all as a master of argument. ...