Principle of Individuation

The Principle of Individuation is a criterion which supposedly individuates or numerically distinguishes the members of the kind for which it is given, i.e. by which we can supposedly determine, regarding any kind of thing, when we have more than one of them or not. It is also known as a 'criterion of identity' or 'indiscernibility principle'. The history of the consideration of such a principle begins with Aristotle. It was much discussed by the medieval philosopher Duns Scotus (c. 1266–1308) with his "haecceity" and later, during Renaissance, by Francisco Suárez (1548–1617), Bonaventure Baron (1610–1696) and Leibniz (1646–1716). Some philosophers have denied the need for any such principle.