Immanuel Kant

1724-1804. German philosopher. Born in Königsberg, Prussia, into a Pietist* family, he lived there all his life. He was professor of logic and metaphysics in the university from 1770. His contact with the ideas of David Hume* “awoke him from his dogmatic slumbers” and turned him into the “critical” philosopher of the Critique of Pure Reason and later works. Thenceforth his aim was to show how reason functions in the acquisition of knowledge, and how the a priori knowledge which (according to Kant) the mind has, in logic, mathematics, and physics, can be justified; to preserve the notion of human freedom; and to give an account of the true nature of morality. The only actions that are moral are those which are in accordance with the Categorical Imperative and which are performed from a sense of duty alone. Nonmoral reasoning is by contrast hypothetical, not categorical in character.

His inquiry into the limits of knowledge demonstrates that metaphysical knowledge (including knowledge of God) is impossible; for all our knowledge arises from sense experience, although it does not end there, for the general structure of knowledge is given by the combinatory power of the human mind: neither reason nor sense experience can provide knowledge by itself. The classical rational proofs of the existence of God have to be abandoned. This denial of the knowledge of God makes room for faith. God, though unknowable, is still required (postulated) by practical reason, since the moral law demands that we should promote the highest good (happiness commensurate with virtue) which only God can bring about. The way is thus open for “rational faith,” that is, the viewing of all one's duties as divine commands.

Kant's view that any knowledge of God is impossible has been extremely influential in Protestantism. Theology has become anthropology. On it has been based the romanticism of Schleiermacher* and the ethical religion of Ritschl.* Less obviously but just as surely, Karl Barth's* “wholly other” God has connections with Kant's unknowable God. With the view that God is unknowable has gone a recasting of classic dogmatic theology, from the notion of revelation onward.