We do not hold the belief that this earth is a realm of misery where man is doomed to destruction. We do not think that tragedy is our natural fate and we do not live in chronic dread of disaster. We do not expect disaster until we have specific reason to expect it-and when we encounter it, we are free to fight it. It is not happiness, but suffering that we consider unnatural. It is not success, but calamity that we regard as the abnormal exception in human life.