The only thing which we can safely prophesy is the one thing which is always called impossible. Again and again we are told, by all sorts of priggish and progressive persons, that mankind cannot go back. The answer is that if mankind cannot go back, it cannot go anywhere. Every important change in history has been founded on something historic: and if the world had not again and again tried to renew its youth, it would have been dead long ago.

-Robert Louis Stevenson (1927)