Universals

Universals are repeatable properties, relations, or kinds that can be instantiated by multiple particular things. Whether they exist independently of those things is a central metaphysical dispute.

Nominalism: Nominalism denies that universals exist as entities distinct from particular things or linguistic practices. It rejects universals as real shared entities and explains common predication without them.
Instantiation: Instantiation is the relation by which a particular is said to possess or exemplify a property or kind. It names the relation through which a universal is present in its particular instances.
Particular: A particular is an individual entity located at a specific place and time, such as one person or tree. Universals are contrasted with the individual things that instantiate them.
Plato: Plato was an ancient Greek philosopher whose dialogues developed the theory of Forms. His Forms became the classical model for universals existing independently of particulars.
Problem of universals: The problem of universals asks how distinct particulars can share properties, kinds, or relations. This is the broader dispute in which competing accounts of universals take shape.
Trope theory: Trope theory holds that properties are particular, unrepeatable instances rather than universals shared by many things. It replaces one repeatable universal with numerically distinct property-instances in similar things.
Predication: Predication is the attribution of a property or relation to a subject in a statement. Statements such as “Socrates is wise” express the sharing that theories of universals must explain.
Property: A property is a feature that can be attributed to an object, such as its color, shape, or mass. Universals are one proposed account of how properties can recur across distinct objects.
Aristotle: Aristotle was an ancient Greek philosopher who developed systematic accounts of substance, predication, and nature. He argued that universals are found in particular things rather than in a separate realm.
Natural kind: A natural kind is a classification whose members share features grounded in nature rather than merely convention. Whether kinds are universals affects whether scientific classifications track real shared structures.

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