The Idea of Immortality as an Imaginative Projection of an Indefinite Moral Future

In his Critique of Pure Reason, Kant famously includes immortality as one of the three “ideas” that give rise to “unavoidable problems of reason” (KrV, B7)1 and thereby constitute the basic subject-matter of metaphysics. Interpreters have paid a great deal of attention to the other two ideas, God and freedom; yet very few studies of Kantian immortality have ever been undertaken. This should come as no surprise, once we realize that Kant himself used the word “immortality” and its cognates only 40 times in all three of his great Critiques. (By comparison, forms of the words “God” and “free(dom)” appear 119 and 509 times, respectively, in the three Critiques.) Kant’s theory of immortality – if he can be said to have one – is therefore exceedingly difficult to understand. For example, he says at one point (KrV, B395n): “Metaphysics has only three ideas as the proper purpose of its investigation: God, freedom, and immortality – and in such a way that the second concept, when combined with the first, is to lead to the third as a necessary conclusion.” How are we to understand this claim ? Does Kant really mean that combining the concept of freedom with the concept of God somehow gives rise to immortality as a necessary inference? In any case, why does Kant say so little about immortality, even though he portrays it as one of three ideas that constitute the “final aim” of all metaphysical speculation ? These and other puzzles raised by Kant’s occasional comments on immortality will be the focus of this paper.