Eternal return

Eternal return (also known as eternal recurrence) is a theory that the universe and all existence and energy has been recurring, and will continue to recur, in a self-similar form an infinite number of times across infinite time or space. The theory is found in Indian philosophy and in ancient Egypt and was subsequently taken up by the Pythagoreans and Stoics. With the decline of antiquity and the spread of Christianity, the theory fell into disuse in the Western world, with the exception of Friedrich Nietzsche, who connected the thought to many of his other concepts, including amor fati. Eternal return relates to the philosophy of predeterminism in that people are predestined to continue repeating the same events over and over again.

Heinrich Heine wrote:

Time is infinite, but the things in time, the concrete bodies, are finite. They may indeed disperse into the smallest particles; but these particles, the atoms, have their determinate numbers, and the numbers of the configurations which, all of themselves, are formed out of them is also determinate. Now, however long a time may pass, according to the eternal laws governing the combinations of this eternal play of repetition, all configurations which have previously existed on this earth must yet meet, attract, repulse, kiss, and corrupt each other again...

Nietzsche calls the idea "horrifying and paralyzing", referring to it as a burden of the "heaviest weight" imaginable. He professes that the wish for the eternal return of all events would mark the ultimate affirmation of life:

What, if some day or night a demon were to steal after you into your loneliest loneliness and say to you: 'This life as you now live it and have lived it, you will have to live once more and innumerable times more; and there will be nothing new in it, but every pain and every joy and every thought and sigh and everything unutterably small or great in your life will have to return to you, all in the same succession and sequence' ... Would you not throw yourself down and gnash your teeth and curse the demon who spoke thus? Or have you once experienced a tremendous moment when you would have answered him: 'You are a god and never have I heard anything more divine.' [The Gay Science, §341]

To comprehend eternal recurrence in his thought, and to not merely come to peace with it but to embrace it, requires amor fati, "love of fate": My formula for human greatness is amor fati: that one wants to have nothing different, not forward, not backward, not in all eternity. Not merely to bear the necessary, still less to conceal it—all idealism is mendaciousness before the necessary—but to love it.

In Carl Jung's seminar on Thus Spoke Zarathustra, Jung claims that the dwarf states the idea of the eternal return before Zarathustra finishes his argument of the eternal return when the dwarf says, "'Everything straight lies,' murmured the dwarf disdainfully. 'All truth is crooked, time itself is a circle.' "However, Zarathustra rebuffs the dwarf in the following paragraph, warning him against over-simplifications.

— https://en.wikipedia.org/wiki/Eternal_return