Restrictions in the application of Leibniz’s Principle of Intersubstitutivity of Identicals Salva Veritate

Abstract

The Principle of Intersubstitutivity of Identicals Salva Veritate, which represents an important and central piece of Leibniz’s theory of demonstration (not to mention its ontological implications), has received a critical review that it carries a confusion between use and mention. Contrary to this criticism, this paper defends the thesis that the principle is not susceptible to the alleged confusion, by appealing to Leibniz’s distinction between “considering the way of conceiving” and “considering the thing itself”. The way this distinction is introduced, however, is accompanied by the need of making some restrictions on the application of that principle.