Nominalism

Nominalism (from Latin nomen, name) — A philosophical position in the debate over universals: do general terms such as “humanity”, “redness”, or “triangle” refer to real, independent entities, or are they merely names? Nominalism answers that universals have no real existence outside mind or language — only concrete individual particulars exist.

The problem of universals is one of the oldest and most persistent in the history of philosophy, with roots in the Aristotelian distinction between individual substance and form, and in the Platonic discussion of the Forms. The medieval version of the debate takes as its starting point the Introduction (Isagoge) by Porphyry to Aristotle’s Categories, where he raises — and deliberately leaves unanswered — three questions: do genera and species exist in themselves or only in thought? If they exist, are they corporeal or incorporeal? Do they exist separately from sensible things or within them? Boethius transmitted these questions to the Latin Middle Ages, where they gave rise to the controversy over universals.

Three positions emerged. Realism (also called Realism about Universals, to distinguish it from modern usage) holds that universals have real existence: either outside things and prior to them (ante rem — the Platonic position), or within things themselves (in re — the Aristotelian position, or the moderate realism of Thomas Aquinas). Extreme Nominalism (associated with Roscellinus of Compiègne, c. 1050–c. 1120) denies universals any reality whatsoever — they are flatus vocis, “a puff of air”, mere sounds. Conceptualism (an intermediate position, associated with Peter Abelard, c. 1079–1142, and later with William of Ockham, c. 1285–1347/49) holds that universals exist as concepts or mental representations — they have psychological but not extra-mental reality.

William of Ockham is the most systematic and influential medieval nominalist. For Ockham, universals are terms (signs) that can be predicated of many individuals — they perform a semiotic function without presupposing abstract entities. The methodological rule known as “Ockham’s Razor” — “do not multiply entities beyond necessity” (entia non sunt multiplicanda praeter necessitatem) — is traditionally attributed to Ockham, though the exact formulation is a later summary rather than a literal quotation from his texts. Its function is to guide ontological parsimony: if a theory does not need abstract entities to be true, we should not posit them.

In modern and contemporary philosophy the debate continues in reformulated terms. Thomas Hobbes holds that universals are names imposed by convention. In the twentieth century, W.V.O. Quine proposes that a theory’s ontological commitments are measured by the variables it quantifies over: to assert the existence of x is to quantify over x. Mathematical theories, for example, apparently quantify over abstract objects — but the nominalist seeks paraphrases that eliminate this commitment. The trope theory is a contemporary nominalist proposal: instead of universals, it posits tropes (particular instances of properties) — the redness of this apple is a particular entity, distinct from the redness of that one, though similar to it. Tropes are particulars; resemblance requires no universal.

← Glossary