Terminology Tuesday: Nominalism

Nominalism is the view that neither universals nor essences are real (see REALISM), that is, they have no extramental existence. Everything is particular. A universal is a general or class concept that includes all the particulars in it. The class is an abstract concept that exists only in the mind (see EPISTEMOLOGY; FIRST PRINCIPLES).

“Humanness” is a general concept that includes all individual human beings. But nominalists insist that humanness does not exist; only individuals really exist. “Triangleness” is a universal, but it too exists only in the mind. In reality only individual triangular shaped things exist.

Nature of Nominalism. Nominalism can be best viewed by contrast with opposing conceptions. Following Plato, the Medieval theologian Gilbert of Porree affirmed that universals are real things. On the other end of the spectrum, medieval thinker Roscellinus (1050–1125) contended that universals are a mere sign, “a puff of the voice.” Peter Abelard (1079–1142) claimed that universals are nouns formed by a confusion of particular ideas. William of Ockham (1280–1349) was a true nominalist. To him, a universal is a mere abstract concept in the mind. John Duns Scotus (1266–1308) believed that universals are bonds or common natures that in themselves are neither universal or particular. Nature as such is neutral; it can be generalized by the mind or concretized with “thisness.” Thomas Aquinas (1224–1274) held a realistic position (see REALISM), declaring that a universal is mental being. It is a form existing in the mind but rooted in reality.

Problems with Nominalism. From a realistic perspective, nominalism has problems, some with serious consequences for important Christian beliefs.

Nominalism Leads to Skepticism. If there is no basis in reality for our general ideas, then words tell us nothing about reality. We must remain skeptical about the real world. But complete skepticism (see AGNOSTICISM) is self-defeating. If it suspended judgment about its own central affirmation, as it demands we do about everything else, the skeptic would have to be skeptical of skepticism. That would destroy the basis for skepticism.

Nominalism Leads to Moral Relativism. If universals have no basis in the real world, there can be no universal moral values. Everything would simply be particular or situational. There would be nothing that one ought to do in every circumstance (such as, be loving or just). However, the denial of all absolutes is self-defeating (see MORALITY, ABSOLUTE NATURE OF), for the claim that one absolutely ought not believe in moral absolutes is a moral absolute of its own.
Nominalism Leads to Heresy. All orthodox Christians believe that God has one essence or nature, and Christ has two natures (see TRINITY). But, if nominalists are right, then God has no nature. Likewise, Christ could not have both a human and a divine nature, as the creeds assert (see CHRIST, DEITY OF). Hence, nominalism is a denial of historic, creedal, orthodox Christianity.
Nominalism Overreacts to Platonism. Plato (428–348 B.C.) believed everything that exists is part of an eternal essence or form. Nominalists deny such changeless essences, affirming that everything is particular or individual. They fail to acknowledge, however, that these are not the only two options. Aquinas showed that, while universals exist in the mind as abstractions from particulars, they are rooted in reality. There is no such entity as human nature. However, each human being shares essential characteristics (= nature or essence). So the abstraction referring to what we call humanness is not a mere name; it is a referent to a relationship that truly exists in reality.

Sources
  E. Gilson, The History of Christian Philosophy in the Middle Ages  J. F. Harris, Against Relativism  J. P. Moreland, Universals, Qualities, and Quality-Instances.  William of Ockham, Ockham: Philosophical Writings  W. V. Quine, From a Logical Point of View  Thomas Aquinas, Summa Theologica.

Geisler, N. L. (1999). Nominalism. In Baker encyclopedia of Christian apologetics (pp. 543–544). Grand Rapids, MI: Baker Books.