Nominalism, a famous controverted doctrine of the middle ages, respecting the nature of our general or abstract ideas, or of 'universals.' It was contended by some that abstractions—as a circle in the abstract, beauty, right—had a real existence apart from round things, beautiful objects, right actions. This was called Realism. Those who held the opposite view were called Nominalists, because they maintained that there is nothing general but names; the name 'circle' is applied to everything that is round, and is a general name; but no independent fact or property exists corresponding to the name. Specifically the controversy was as to the existence of 'universals' or of genera and species, and arose out of a passage in the Latin translation of Porphyry's Isagoge. The watchwords of three schools were universalia ante res, 'the universals before the concrete things,' of Platonic Realism; universalia in re, 'the universals in the thing,' held to be Aristotelian Realism; universalia post rem, 'the universals after the thing,' covering both Nominalism (that the universals were but flatus vocis, sounds) and Conceptualism (that the universals had an existence in the mind of the thinker).
Scholastic Realism of what was regarded as the Aristotelian type prevailed until the 11th century, when Roscelin defended a distinctly Nominalistic doctrine. Unhappily he applied his philosophy to the doctrine of the Trinity, and arrived at a tritheistic heresy, which (and Nominalism with it) was condemned by the church. Henceforward Nominalism carried with it, not unreasonably altogether, a savour of heresy and rationalism, and Realism was dominant, though the controversy raged throughout the 12th century. Abelard was a modified Realist; Albertus Magnus, Aquinas, and Duns Scotus were Realists of a kind, though in the 13th and 14th centuries the feud between Nominalists and Realists was no longer the central debate of scholasticism. Nominalism triumphed with William of Ockham (died 1347), with whom scholasticism may be held to have begun to dissolve. See SCHOLASTICISM, and works quoted there; the articles on the chief mediæval thinkers; the article PHILOSOPHY; and monographs by Exner (1841), Köhler (1858), and Löwe (1876).