Universals

Repeatable features, such as redness, that many separate things can share at once.

Also: universal, problem of universals, realism about universals

What it means

A universal is an entity that can be wholly present in many things at the same time. If two apples are exactly the same shade of red, a realist about universals says one and the same redness is present in both. Plato placed universals in a separate realm of Forms; Aristotle located them in things themselves. Medieval thinkers, following Porphyry and Boethius, debated whether universals exist in things, in minds or only in words. In twentieth-century philosophy D. M. Armstrong was the best-known defender of universals. Nyāya philosophers in India defended realism about universals, holding that a universal is perceived as instantiated in individuals. The opposing view is nominalism.

The questions it belongs to

• 1.1.2 Universals and ParticularsA tomato and a fire engine are both red. Is there something they share?
• 1.1.4 Abstract ObjectsDoes the number seven exist?

Thinkers

• Plato
• Aristotle
• Boethius
• D. M. Armstrong

Traditions

• Greek & Roman
• Medieval Christian
• Indian
• Analytic

To read

• Apology — Plato
• Categories — Aristotle
• Cratylus — Plato

Sources and further reading

• Nominalism in Metaphysics (Stanford Encyclopedia of Philosophy)
• The Medieval Problem of Universals (Stanford Encyclopedia of Philosophy)
• Nyaya (Internet Encyclopedia of Philosophy)
• Properties (Stanford Encyclopedia of Philosophy)

Written by the Coordinates of Thought editors and checked against the sources above on 29 October 2026. Not peer-reviewed. How we write and check.

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