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Portrait of Jean Buridan
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Jean Buridan

Nominalist logician of Paris who theorized 'impetus', anticipating inertia.

ScholasticismLate MedievalLatin Christian1301–1362 CE◦ Béthune, Artois (France)14th century CE

Overview

The most important arts master of fourteenth-century Paris, Jean Buridan developed Ockham's nominalist logic into a rigorous, influential system while remaining a secular philosopher who never became a theologian. In physics he advanced the theory of 'impetus' — an impressed force keeping projectiles and the heavens in motion — a crucial step toward the modern concept of inertia. His name survives in the paradox of 'Buridan's ass', illustrating problems of free choice.

What they supported — and why

Impetus theory

SupportedA mover impresses a lasting 'impetus' on a body, which keeps it moving until resistance consumes it.

WhyProjectiles continue after leaving the hand, so the cause of continued motion must be something transferred into the body itself — anticipating inertia.

Nominalist logic and reference

SupportedUniversals are terms and concepts; careful analysis of how terms 'supposit' (refer) resolves philosophical problems.

WhyRigor about language and reference, not hidden entities, is the key to sound reasoning.

Choice and the weighing of reasons

SupportedThe will chooses according to the intellect's judgement, yet can defer when reasons are balanced.

WhyRational choice tracks the perceived good, but a perfect balance of reasons (as in 'Buridan's ass') raises the question of how the will finally decides.

Causes championed

  • Rigorous logic
  • A naturalistic science of motion
  • The autonomy of the arts faculty

Issues wrestled with

  • What keeps bodies in motion?
  • How do universal terms refer?
  • How does the will choose?

Hurdles faced

  • Keeping philosophy independent of theology in a charged era
  • His works later placed under suspicion

Works & books

2 catalogued. Status shows how much survives to today.

Summulae de Dialectica

Survives

His comprehensive and influential textbook of nominalist logic.

Questions on Aristotle's Physics and On the Heavens

Survives

Where he develops impetus theory toward a new science of motion.

Read the texts free

Their works online — Open Library catalogues 50 works & editions.

Influenced

Nicole Oresme and Albert of Saxony (his pupils)the impetus traditionGalileo and early modern mechanics

In their words

“The impetus impressed on a body by its mover keeps it moving until resisting forces destroy it.”

— Questions on the Physics (paraphrase)

Legacy

He carried nominalist logic to its height and, with impetus theory, took a decisive step from Aristotelian toward modern physics.

Further reading

Cross-checked against these authoritative references.

Authority records

Linked into the wider knowledge graph via Wikidata — the stable spine other sources hang off.