Period: ~600–400 B.C. | Context: transition from myth (mythos) to rational thought (logos)

Historical Context

Philosophy is born in Greece from specific conditions: the poetry of Homer and Hesiod, public and Orphic religions, and the socioeconomic conditions of the poleis. The Pre-Socratics break with myth and seek a unique rational principle — the arché — to explain the totality of things. The knowledge sought is sophia, logos, aletheia, and episteme.

I. Pre-Socratics

1. Monists of the School of Miletus

Thales of Miletus (~624–546 B.C.)

  • Arché: water (not the water we drink, but the moist principle that pervades everything)
  • First philosopher of the Western tradition; affirmed that the earth floats on water
  • References: no direct works; we know him through Aristotle (Metaphysics I, 3)

Anaximander (~610–546 B.C.)

  • Arché: apeiron — the infinite/unlimited, divine principle in which there is unity of opposites
  • The world derives by separation of contraries (hot/cold, dry/moist): hence injustice, which beings expiate by dissolving into the apeiron
  • References: fragment preserved in Simplicius (Commentary on the Physics)

Anaximenes (~585–525 B.C.)

  • Arché: air — the apeiron of Anaximander becomes determined by air; the world derives by condensation (stone, earth) and rarefaction (fire)
  • References: fragments in Simplicius and Theophrastus

2. Pythagoreans

Pythagoras of Samos (~570–495 B.C.)

  • Arché: number — limit and unlimited generate all numbers, which generate all things
  • Heirs of Orphism: metempsychosis (transmigration of the soul between bodies) and purification
  • Mathematics as the path of purification of the soul
  • References: Philolaus of Croton (On Nature); Iamblichus (Life of Pythagoras)

3. Heraclitus of Ephesus (~535–475 B.C.)

  • Arché: fire — principle of constant becoming (“everything flows,” panta rhei)
  • Dialectic of opposites: contraries are identical in their root (the way up and down is the same); the logos governs all
  • Fire transforms into all things and all things into fire — an eternal cycle of transformations along the ascending and descending path
  • References: fragments preserved in Hippolytus (Refutation of All Heresies) and Clement of Alexandria

4. Eleatic School

Xenophanes (~570–475 B.C.)

  • Critique of anthropomorphism: men create gods in their image; a true god would be unique, eternal, immobile, entirely different from men
  • References: fragments in Clement and Simplicius

Parmenides of Elea (~515–450 B.C.)

  • Ontology: “Being is; non-being is not”
  • Being: eternal, immobile, homogeneous, perfect, one, ungenerated, incorruptible
  • Two paths: truth (reason → immobile being) and error (senses → becoming/illusory multiplicity)
  • The opposites (light/night) are both being; hence unity
  • References: poem On Nature (fragments in Simplicius)

Zeno of Elea (~490–430 B.C.)

  • Disciple of Parmenides; defends the immobility of being by reductio ad absurdum
  • Paradoxes: Achilles and the tortoise; the immobile arrow — demonstrate that movement and multiplicity are contradictory
  • References: Aristotle (Physics VI, 9); fragments in Simplicius

Melissus of Samos (5th cent. B.C.)

  • Extends Eleatic being: infinite both spatially and temporally
  • References: fragments in Simplicius

5. Pluralists

Empedocles (~490–430 B.C.)

  • 4 elements (rhizomata): earth, water, fire, air — incorruptible, eternal, homogeneous
  • 2 forces: Love (philia) aggregates; Strife (neikos) disaggregates — cosmic cycle
  • There is no true birth nor death, only mixture and separation
  • References: poems On Nature and Purifications (fragments via Simplicius and Clement)

Anaxagoras (~500–428 B.C.)

  • Homeomeries (seeds): everything is in everything; each thing contains parts of all things in varying proportions
  • Nous (Cosmic Intelligence): a separate, pure principle that orders the world and initiates movement
  • References: fragments in Simplicius; Plato (Phaedo 97c–99d); Aristotle (Metaphysics I, 3)

Leucippus (mid-5th c. B.C.) and Democritus (~460–370 B.C.) — Atomism

  • Atoms (indivisible) and void: all that exists is atom and void
  • Eternal movement; random combinations of atoms generate infinite worlds
  • Theory of effluvia: knowledge occurs when eídola (atomic films shed from the surfaces of objects) reach the sense organs, causing perception
  • Materialism and mechanism: no cosmic purpose or intelligence
  • References: Aristotle (On the Soul, Physics); Diogenes Laërtius (Lives of the Philosophers, IX)

II. Sophists (~450–380 B.C.)

Context

Men who traveled through the poleis selling their knowledge (from sophus, wise). For Plato, they were impostors; historically, they were teachers of the new political arete — rhetorical and argumentative skill. They developed disciplines that partially correspond to what Scholasticism would call the trivium (grammar, rhetoric, dialectic).

Groups

1st Generation

Protagoras of Abdera (~490–420 B.C.)

  • Relativism: “Man is the measure of all things” (homo mensura) — what seems true for each one is true for each one
  • Agnostic about the gods: cannot know if they exist
  • References: Plato (Protagoras, Theaetetus); fragments in Diogenes Laërtius

Gorgias of Leontini (~483–375 B.C.)

  • Radical skepticism (3 theses): 1) nothing exists; 2) even if it did exist, we could not know it; 3) even if we knew it, we could not communicate it
  • Supreme master of rhetoric: language does not reproduce reality, but creates persuasive effects
  • References: Plato (Gorgias); treatise On Non-Being (summarized by Sextus Empiricus)

Prodicus of Ceos (~465–395 B.C.)

  • Technique of synonymy: precise distinction of synonyms for effective public debates

Eristics

  • Verbal disputes as ends in themselves (argumentation for the sake of victory, not truth)

Political Sophists

  • Critias and Thrasymachus: justice is the advantage of the stronger; conquest of power through rhetoric

Naturalists

  • Hippias and Antiphon: difference between natural law (physis) and positive law (nomos) — anticipate natural law

General References

  • Plato (critique in the dialogues Meno, Gorgias, Protagoras, Sophist, Euthydemus)
  • W. K. C. Guthrie, The Sophists (1971)
  • Giovanni Reale & Dario Antiseri, History of Philosophy, vol. 1 — chapters on Sophists