What if a demon were to creep after you one night, in your loneliest loneliness, and say, ‘This life which you live must be lived by you once again and innumerable times more; and every pain and joy and thought and sigh must come again to you, all in the same sequence. The eternal hourglass will again and again be turned and you with it, dust of the dust!’ Would you throw yourself down and gnash your teeth and curse that demon? Or would you answer, ‘Never have I heard anything more divine’?