Abstract

Kant’s critique of the ontological and other related arguments for the existence of God was part of his groundbreaking critique of traditional rational theology (a classical branch of metaphysics). Frege as a philosopher was not particularly interested in rational theology or metaphysics, but he used his interpretation of Kant’s critique of the ontological argument to elucidate some of his most important logical notions and distinctions. Frege was not a Kant-scholar, who spent a lot of his research time investigating Kant’s philosophical views. Nevertheless, he was informed about Kant’s conception of logic, his epistemology, his foundation of mathematics and his critique of the ontological argument. In this article, I will argue (i) that Frege endorsed two objections against the ontological argument, (ii) that his philosophy teachers, Kuno Fischer and Hermann Lotze, are the most probable main sources of Frege’s knowledge about Kant’s critique of the ontological argument, and (iii) that their views on this topic influenced Frege’s view on existence and his way of understanding of Kant’s critique of the ontological argument.