School of thought
Atomism
Intellectual current
Classification
- Period
- c. 440-370 BCE
- Regions
- Europe · Origin not established
- Domains
- Metaphysics, Philosophy of Nature
Overview
Ancient Atomism, developed by Leucippus and Democritus, proposed that all reality consists of indivisible particles (atoms) moving through void (empty space). This materialist worldview explained all phenomena — from perception to cosmology — through the mechanical interactions of atoms, without recourse to purpose or design.
Key ideas
- Atoms and Void: Reality consists entirely of an infinite number of indivisible, eternal particles (atoms) differing only in shape, size, and arrangement, moving through empty space.
- Mechanical Causation: Everything occurs by necessity through the collision and combination of atoms. There is no teleology or design — only matter in motion.
- Cheerfulness (Euthymia): Democritus held that the goal of life is tranquility of mind, achieved through moderation and an understanding of the natural world.
Key figures
Leucippus · Democritus
Questions engaged
- How Many Fundamental Substances?
As Aristotle reports them, Leucippus and Democritus answered with infinitely many substances of one kind: indivisible atoms of a single uniform stuff, differing only in shape, arrangement and position. Beside them is the void, which they called 'what is not' yet held to be no less real than what is. Everything else is the atoms' arrangement.
Influenced by
- Eleaticism
- Pluralists
Extended the pluralist response to Parmenides — Empedocles' roots and Anaxagoras' seeds — replacing qualitatively distinct principles with uniform atoms moving in the void.
Later connections
- Epicureanism Influenced by this tradition
Epicurus took over Democritus' indivisible bodies moving in empty space, where shape, size and arrangement explain everything else. He then gave those atoms weight and an unpredictable swerve, so that motion would not run by the strict necessity Democritus accepted.
- Pyrrhonism Influenced by this tradition
Drew on the Atomist emphasis on the unreliability of the senses; Pyrrho was a pupil of the Democritean Anaxarchus.
References
- Stanford Encyclopedia of Philosophy, Ancient Atomism
- Aristotle, On Generation and Corruption I.8, 324b35–325a32, reporting Leucippus's formulation of the atomist theory. The passage gives the doctrine, not its date
- Stanford Encyclopedia of Philosophy, Leucippus, §1 'Life and Works': 'His dates are unknown, other than that he lived during the fifth century BCE.' The start year used here places that formulation within the century and is an editorial approximation, which is what datePrecision records
- Stanford Encyclopedia of Philosophy, Leucippus, §1 — Formation: Leucippus's birthplace is variously reported as Elea, Abdera or Miletus, and the site of the atomist formulation is not established.
- Aristotle, On Generation and Corruption I.8, 324b35–325a32 (atomism as a response to Eleatic monism)
- C. C. W. Taylor, The Atomists: Leucippus and Democritus (University of Toronto Press, 1999)
- G. S. Kirk, J. E. Raven and M. Schofield, The Presocratic Philosophers (2nd ed., Cambridge University Press, 1983), ch. 15 (Leucippus and Democritus)
- Aristotle, Metaphysics A.4, 985b4–20 (Leucippus and Democritus make the full and the empty, being and not-being, the elements, say that what is is no more than what is not, and trace every other difference to the shape, arrangement and position of the full)
- The Atomists: Leucippus and Democritus — C. C. W. Taylor
- Early Greek Philosophy — Jonathan Barnes