The post-war rationalist and rationalism have become somewhat anachronistic by continuing to swear by a physical science which is now no more what it was in the last century. The humility of twentieth-century science is yet to invade the citadel of that rationalism. That wholesome invasion will be accomplished when rationalism recognizes the distinction between religion, on the one side, and superstition and obscurantism, on the other. But, today, its fight against all religion, in the absence of this recognition, has itself become an irrational venture. It can overcome this irrationality only when it grasps the limitations of the reason it handles, and recognizes the truth of the march of reason.