The traditional arguments for the existence of God have been fairly thoroughly criticised by philosophers. But the theologian can, if he wishes, accept this criticism. He can admit that no rational proof of God's existence is possible. And he can still retain all that is essential to his position, by holding that God's existence is known in some other, non-rational way. I think, however, that a more telling criticism can be made by way of the traditional problem of evil. Here it can be shown, not that religious beliefs lack rational support, but that they are positively irrational, that the several parts of the essential theological doctrine are inconsistent with one another, so that the theologian can maintain his position as a whole only by a much more extreme rejection of reason than in the former case. He must now be prepared to believe, not merely what cannot be proved, but what can be disproved from other beliefs that he also holds.