(Lat. nominalis, “belonging to a name”). The theory of knowledge which insists that universals are created by reason. Essences have no independent reality of their own, but are only names or mere vocal utterances. Reality attributed only to particulars or individual things. This epistemological position is in opposition to Platonic realism, which insisted that universal essences existed. The nominalistic pattern of thought was first introduced by Porphyry* (233-304) who attributed it to Aristotle.

In the Middle Ages, nominalism emerged as a strong reaction to realism and was championed by Roscellinus* of Compiègne (c. 1050-1125). Abelard* gave these early disputes prominence when he tried (somewhat successfully) to find a middle position. His efforts led to a moratorium until William of Ockham* (1280-1349) revived nominalism and established the first frankly nominalistic system (ontological nominalism). He taught that terms are mental realities and are universals only insofar as they can stand for many. The terms themselves are like any reality, singular and unique. This universality is purely functional and does not refer to a common essence possessed by many things outside the mind. Reality was a collection of absolute singulars and, therefore, could not give evidence or provide scientific support for God's existence. This is clearly anti-Thomistic. Faith became the grounds of belief. The Ockhamist School eventually faded away, but nominalistic thought has continued to have its effect on philosophical thought. The teachings of John Locke,* David Hume,* and certain branches of logical positivism incorporate some of the thought of the Ockhamists.