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 of Eternal return 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.

Premise

The basic premise proceeds from the assumption that the probability of a world coming into existence exactly like our own is nonzero. If space and time are infinite, then it follows logically that our existence must recur an infinite number of times.

In 1871 Louis Auguste Blanqui, assuming a Newtonian cosmology where time and space are infinite, claimed to have demonstrated eternal recurrence as a mathematical certainty.

Classical antiquity

In ancient Egypt, the scarab (dung beetle) was viewed as a sign of eternal renewal and reemergence of life, a reminder of the life to come. The Mayans and Aztecs also took a cyclical view of time.

In ancient Greece, the concept of eternal return was connected with Empedocles, Zeno of Citium, and most notably in Stoicism.

Indian religions

The concept of cyclical patterns is prominent in Indian religions, such as Jainism, Hinduism, Sikhism and Buddhism among others.

The important distinction is that events don’t repeat endlessly but souls take birth until they attain salvation. The wheel of life represents an endless cycle of birth, life, and death from which one seeks liberation.

In Tantric Buddhism, a wheel of time concept known as the Kalachakra expresses the idea of an endless cycle of existence and knowledge.

Friedrich Nietzsche

The concept of “eternal recurrence“, the idea that with infinite time and a finite number of events, events will recur again and again infinitely, is central to the writings of Friedrich Nietzsche.

As Heidegger points out in his lectures on Nietzsche, Nietzsche’s first mention of eternal recurrence, in aphorism 341 of The Gay Science, presents this concept as a hypothetical question rather than postulating it as a fact.

According to Heidegger, it is the burden imposed by the question of eternal recurrence—whether or not such a thing could possibly be true—that is so significant in modern thought:

“The way Nietzsche here patterns the first communication of the thought of the ‘greatest burden’ [of eternal recurrence] makes it clear that this ‘thought of thoughts’ is at the same time ‘the most burdensome thought.’ “

The thought of eternal recurrence appears in a few of his works, in particular, §285 and §341 of The Gay Science and then in Thus Spoke Zarathustra.

The most complete treatment of the subject appears in the work entitled Notes on the Eternal Recurrence, a work which was published in 2007 alongside Søren Kierkegaard’s own version of eternal return, which he calls ‘repetition‘. Nietzsche sums up his thought most succinctly when he addresses the reader with:

“Everything has returned. Sirius, and the spider, and thy thoughts at this moment, and this last thought of thine that all things will return”.

However, he also expresses his thought at greater length when he says to his reader:

“Whoever thou mayest be, beloved stranger, whom I meet here for the first time, avail thyself of this happy hour and of the stillness around us, and above us, and let me tell thee something of the thought which has suddenly risen before me like a star which would fain shed down its rays upon thee and every one, as befits the nature of light. – Fellow man! Your whole life, like a sandglass, will always be reversed and will ever run out again, – a long minute of time will elapse until all those conditions out of which you were evolved return in the wheel of the cosmic process. And then you will find every pain and every pleasure, every friend and every enemy, every hope and every error, every blade of grass and every ray of sunshine once more, and the whole fabric of things which make up your life. This ring in which you are but a grain will glitter afresh forever. And in every one of these cycles of human life there will be one hour where, for the first time one man, and then many, will perceive the mighty thought of the eternal recurrence of all things:- and for mankind this is always the hour of Noon”.

This thought is indeed also noted in a posthumous fragment. The origin of this thought is dated by Nietzsche himself, via posthumous fragments, to August 1881, at Sils-Maria.

In Ecce Homo (1888), he wrote that he thought of the eternal return as the “fundamental conception” of Thus Spoke Zarathustra.

Albert Camus

The philosopher and writer Albert Camus explores the notion of “eternal return” in his essay on “The Myth of Sisyphus“, in which the repetitive nature of existence comes to represent life’s absurdity, something the hero seeks to withstand through manifesting what Paul Tillich called “The Courage to Be“.

Though the task of rolling the stone repeatedly up the hill without end is inherently meaningless, the challenge faced by Sisyphus is to refrain from despair. Hence Camus famously concludes that “one must imagine Sisyphus happy.”

Opposing argument

Nietzsche scholar Walter Kaufmann has described an argument originally put forward by Georg Simmel, which rebuts the claim that a finite number of states must repeat within an infinite amount of time:

Even if there were exceedingly few things in a finite space in an infinite time, they would not have to repeat in the same configurations. Suppose there were three wheels of equal size, rotating on the same axis, one point marked on the circumference of each wheel, and these three points lined up in one straight line. If the second wheel rotated twice as fast as the first, and if the speed of the third wheel was 1/π of the speed of the first, the initial line-up would never recur.

Thus a system could have an infinite number of distinct physical configurations that never recur.

However the example presupposes the possibility of perfect continuity: for instance, if the universe proves to have a quantum foam nature, then the exact quantity of an irrational number cannot be expressed by any physical object.

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*This article was originally published at en.wikipedia.org.