Philosophy
The Problem of Universals: Nominalism vs. Realism
Quick fact
The medieval debate over universals was so intense that it sometimes ended in violence, including the beating of philosopher Peter Abelard.
Why this is interesting
We all know what redness is. But where is it? Is redness a real thing that exists somewhere, or is it just a word we use to describe similar-looking objects?
Read the full explanation
Understanding The Problem of Universals: Nominalism vs. Realism
The problem of universals is about the nature of properties. When we say that a rose and a fire truck are both red, we are using a general term 'redness'. The question is: does that general term refer to something real that exists independently of the red objects? Realists argue that universals (like redness) exist as abstract entities, either in a separate realm (Platonic realism) or in the things themselves (Aristotelian realism). Nominalists argue that only individual things exist; 'redness' is just a name we give to a group of similar objects. This debate has implications for how we understand language, science, and even mathematics.
A deeper explanation
The underlying mechanism of the problem lies in how language maps onto the world. Universals are what explain why different particulars can share the same property. For realists, universals are the ground of resemblance: two objects are red because they both instantiate the same universal redness. For nominalists, there are no universals; the only reason we group objects together is because of their individual qualities, which are either primitive (trope theory) or established by resemblance relations (resemblance nominalism). This debate matters because it influences how we think about abstract concepts, such as numbers, justice, and even scientific laws.