Never has our future been more unpredictable, never have we depended so much on political forces that cannot be trusted to follow the rules of common sense and self-interest—forces that look like sheer insanity, if judged by the standards of other centuries. It is as though mankind had divided itself between those who believe in human omnipotence (who think that everything is possible if one knows how to organize masses for it) and those for whom powerlessness has become the major experience of their lives. On the level of historical insight and political thought there prevails an ill-defined, general agreement that the essential structure of all civilizations is at the breaking point. Although it may seem better preserved in some parts of the world than in others, it can nowhere provide the guidance to the possibilities of the century, or an adequate response to its horrors. Desperate hope and desperate fear often seem closer to the center of such events than balanced judgment and measured insight. The central events of our time are not less effectively forgotten by those committed to a belief in an unavoidable doom, than by those who have given themselves up to reckless optimism.