The fact that the prevailing mood of modern culture was able to transmute the original pessimism of romanticism into an optimistic creed proves the power of this mood. Only occasionally the original pessimism erupts in full vigor, as in the thought of a Schopenhauer or Nietzsche. The subjugation of romantic pessimism, together with the transmutation of Marxist catastrophism establishes historical optimism far beyond the confines of modern rationalism. Though there are minor dissonances the whole chorus of modern culture learned to sing the new song of hope in remarkable harmony. The redemption of mankind, by whatever means, was assured for the future. It was, in fact, assured by the future.

Faith and History: A Comparison of Christian and Modern Views of History (1949)