Nietzsche and the Law of Recurrence

What if a demon crept after you one day or night in your loneliest solitude and said to you: 'This life, as you live it now and have lived it, you will have to live again and again, times without number; and there will be nothing new in it, but every pain and every joy and every thought and sigh and all the unspeakably small and great in your life must return to you, and everything in the same series and sequence - and in the same way this spider and this moonlight among the trees, and in the same way this moment and I myself. The eternal hour-glass of existence will be turned again and again - and you with it, you dust of dust!' - Would you not throw yourself down and gnash your teeth and curse the demon who thus spoke? Or have you experienced a tremendous moment in which you would have answered him: 'You are a god and never did I hear anything more divine!' If this thought gained power over you it would, as you are now, transform and perhaps crush you; the question in all and everything: 'do you want this again and again, times without number?' would lie as the heaviest burden upon all your actions. Or how well disposed towards yourself and towards life would you have to become to have no greater desire than for this ultimate eternal sanction and seal?

Nietzsche, The Gay Science