Eternal Recurrence is a philosophical concept formulated by Friedrich Nietzsche. Nietzsche's concept of the Eternal Recurrence can be understood in two senses: Friedrich Nietzsche, 1882 Friedrich Wilhelm Nietzsche (October 15, 1844 – August 25, 1900) was a highly influential German philosopher, philologist, and psychologist. ...

One, by considering the universe as an infinite series of compositions or configurations, one concludes that the composition of this very moment one is living will—must—occur again. Any given configuration must have a probability greater than zero, being that otherwise it would not have come to pass.

A finite set is the result of necessarily finite aggregate probabilities, meaning that events in the past will again occur in the future. The past and future are thus indistinguishable—and, invoking Occam's razor, one and the same. The fact that the future folds back to the past leads to the conclusion that Time, contrary to any rectilinear model, entails a circular, cyclical characteristic. Occams Razor (also Ockhams Razor or any of several other spellings), is a principle attributed to the 14th century English logician and Franciscan friar, William of Ockham that forms the basis of methodological reductionism, also called the principle of parsimony or law of economy. ...

Two, by considering 'the mind', or a person's consciousness, as a subjective map of the world, (again understood as a series of momentary mental configurations), one may consider that such a 'map' must contain a copy of itself, and that copy a copy as well, ad infinitum. However, the copy's necessary deprecation imposes upon this a quantum limit. It is vaguely speculated that the philosopher may experience a sense of infinite subjective depth, and that this series of 'echos' is its cause.