Eternity

Eternity (or forever) is endless time. It is often referenced in the context of religion, in the concept of immortality, whereby death is conquered, and people may live for an unlimited amount of time (cf. Heaven). The existence of God or gods is said to endure eternally and sometimes also the natural cosmos, in respect to both past and future.

By contrast, the concept of a mathematically infinite duration, is called sempiternity or everlasting. Whereas the eternal is said to be unchanging and outside time; a potentially sempiternal span of time can never come to pass in actuality. Aristotle argued that the cosmos has no beginning.