more from Michèle Friend

Single Idea 8688

[catalogued under 18. Thought / D. Concepts / 1. Concepts / a. Nature of concepts]

Full Idea

The extensional presentation of a concept is just a list of the objects falling under the concept. In contrast, an intensional presentation of a concept gives a characterization of the concept, which allows us to pick out which objects fall under it.

Gist of Idea

Concepts can be presented extensionally (as objects) or intensionally (as a characterization)


Michèle Friend (Introducing the Philosophy of Mathematics [2007], 3.4)

Book Reference

Friend,Michèle: 'Introducing the Philosophy of Mathematics' [Acumen 2007], p.64

A Reaction

Logicians seem to favour the extensional view, because (in the standard view) sets are defined simply by their members, so concepts can be explained using sets. I take this to be a mistake. The intensional view seems obviously prior.