Philosophy of The Middle Ages

The Dispute Between Nominalists and Realists Regarding the Nature of Universal Concepts

A distinctive feature of medieval philosophy is the debate between nominalists and realists concerning the nature of universal concepts, or universals (from the Latin universalis, meaning common or generic), which manifest as ideas. This dispute permeates the entire history of medieval philosophy and, as Hegel remarked, "does it great honor." Two opposing scholastic theories emerge regarding universals: realism and nominalism.

According to realists, universal concepts (universals) exist in reality, forming an independent and incorporeal world of essences that is primary to human thought and individual objects; thus, the universal exists prior to the particular thing, beyond it, serving as its cause and determining its significance in relation to other objects (for example, the idea of humanity gives rise to individual persons; the idea of spherical shape results in the existence of spheres). Notable representatives of medieval realism include Anselm of Canterbury, Thomas Aquinas, William of Champeaux, Walter de Mortagne, and others. Realism continues the "line of Plato," representing the idealistic tendency in Western European philosophy.

Nominalists (from the Latin nomina, meaning names) trace their lineage in medieval philosophy to the "line of Democritus," embodying materialism and rationalism. They assert that only perceptible, tangible things are real, not their ideas—universal concepts (universals). Universals do not have a real (independent of material things) existence; they are merely names or labels for existing entities. Universal concepts arise from human thought and can exist only in the human mind, thus ideally rather than actually. Consequently, any idea is a verbal expression rather than an ontological reality. Key figures of medieval nominalism include John Roscelin, Jean Buridan, A. de Serechal, and Peter of Spain.

It is noteworthy that the controversy between realism and nominalism arose from grappling with a purely theological issue: the nature of the reality of the Holy Trinity. While realism insisted on the reality of the one God with three "faces" or hypostases (the Father, the Son, and the Holy Spirit), nominalism regarded only these hypostases (aspects) of God as real, positing that each could exist independently, thereby denying the reality of divine unity. It is important to highlight that the dogma of the Trinity is one of the fundamental tenets of Christian doctrine. Naturally, the official Church could not acquiesce to such heretical views and thus wholly supported the realist position.

Over time, moderate, compromise versions of the extreme forms of realism and nominalism emerged, aligning with the logic of further philosophical development. According to Thomas Aquinas’s moderate realism (1225-1274), universals exist in three ways: prior to things (ante rem), in the mind of God, in things (in re) as their essential meanings, and after things (post rem) as concepts of them in the mind of the knowing subject.

Moderate nominalism or conceptualism is represented by the scholastics Peter Abelard (1079-1142), Duns Scotus (1265/66-1308), and William of Ockham (1285-1349). This variant of nominalism denies the independent existence of universals outside nature and humanity but does not reduce their existence to the empirical reality of objects; it recognizes the reality of a universal concept as a holistic mental generalization of individual things. Thus, the universal is derived from singular things and exists post facto as knowledge of their common and recurrent characteristics.

The discussion between nominalists and realists was of considerable significance for the further development of philosophy, as it illuminated the problem of the relationship between the categories of the particular and the universal. Realists, in speaking of the real existence of the triune God, effectively justified the objectively idealist thesis of the independent existence of the ideal (universal concepts). In contrast, nominalists, by asserting the reality of the three hypostases of God, defended the real existence of individual, distinct objects and phenomena. Ultimately, this led nominalism to a materialistic thesis about the objective reality of the material and sensory world, which presents itself as a collection of separate things (phenomena, objects, processes, etc.).

Thus, the dominant feature of the medieval philosophical worldview is theocentrism: the focus of philosophers is on God as the highest perfection and the primal foundation of all that exists; all central concepts of medieval philosophical thought are related to God and defined through Him. Serving God is seen as the foundation of morality, and striving to resemble Him is regarded as the ultimate purpose of human life.