Eternal Return - Premise

Premise

The basic premise proceeds from the assumption that the probability of a world coming into existence exactly like our own is finite. If either time or space is infinite, then mathematics tells us that our existence will recur an infinite number of times.

In 1871, Louis Auguste Blanqui, assuming a Newtonian cosmology where time and space are infinite proceeded to show that the eternal recurrence was a mathematical certainty. In the post-Einstein period, there are doubts that time or space is in fact infinite, but many models exist which provide the notion of spatial or temporal infinity required by the eternal return hypothesis.

The oscillatory universe model in physics could be provided as an example of how the universe cycles through the same events infinitely. Stephen Hawking's concept "arrow of time", for example, discusses cosmology as proceeding up to a certain point, after which it undergoes a time reversal (which, as a consequence of T-symmetry, is thought to bring about a chaotic state due to entropy). Hawking and J. Richard Gott have also proposed models by which a (or the) universe could undergo time travel, provided the balance between mass and energy created the appropriate cosmological geometry.

Multiverse hypotheses in physics describe models where space or time is infinite, although local universes with their own big bangs could be finite space-time bubbles.