Philosophy
The Metaphysics of Properties: Universals versus Tropes
Quick fact
The debate between universals and tropes has been alive since Plato and Aristotle, but it remains central to contemporary metaphysics—and it directly influences how philosophers interpret scientific laws.
Why this is interesting
Why do two red apples both seem to share the same color? Is there really a single 'redness' that exists in both, or is each apple's redness a private, one-of-a-kind trait?
Read the full explanation
Understanding The Metaphysics of Properties: Universals versus Tropes
Think of properties as the 'adjectives' of reality—the shapes, colors, and masses that things have. When we say two balls are both round, we are saying they share a property. But what exactly does 'sharing' mean? One answer says there exists a single, 'one-over-many' entity—the universal 'roundness'—that is fully present in both balls. The other answer says there is no single shared entity; instead, each ball has its own particular 'roundness-trope.' These two views offer very different pictures of similarity: universals make resemblance literal identity, while tropes make it a matter of exact similarity between distinct individuals.
A deeper explanation
The universals view (realism) meshes naturally with the idea that there are stable kinds and law-like regularities: both red apples instantiate the same universal, so they truly are similar. The tropes view (trope nominalism) treats every property as a particular, existing only in its bearer; thereby it avoids the strange 'multi-location' of a single entity. However, it then must explain how distinct tropes can be exactly similar—often by positing a primitive resemblance relation. This contrast also drives different theories of substances: with universals, an object is often seen as a substratum 'bare particular' that instantiates universals; with tropes, an object can be viewed as a bundle of tropes. The choice has repercussions for identity (how things persist), causation (whether power transfer involves universals), and the nature of laws (whether they are grounded in universal relations or statistical regularities among tropes).