UNSOLVED WEAKNESSES OF EXTENSIONALISM

The nominalist attitude in medieval logic supported a fully extensional conception of the sense of the expressions. Many arguments against this approach were raised at that time. The authoress would like to show in this article (1) that there is a (hidden) extensional conception of notions in current logic, namely in the interpretation of formal theories and the creation models of them and (2) that, and how, the traditional arguments against the extensional conception are relevant also for logic today.