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5. Theory of Logic / I. Semantics of Logic / 5. Extensionalism

[semantic system built on reference to objects]

4 ideas
Humean conceptions of reality drive the adoption of extensional logic [Ellis]
Extensionality is built into ordinary logic semantics; names have objects, predicates have sets of objects [Bostock]
If an object has two names, truth is undisturbed if the names are swapped; this is Extensionality [Bostock]
Extensionalists say that quantifiers presuppose the existence of their objects [Jacquette]