Eternity

Classical philosophy defines eternity as what exists outside time, as in describing timeless supernatural beings and forces, distinguished from sempiternity which corresponds to infinite time, as described in requiem prayers for the dead. Some thinkers, such as Aristotle, suggest the eternity of the natural cosmos in regard to both past and future eternal duration. Boethius defined eternity as "simultaneously full and perfect possession of interminable life".[2][lower-alpha 1] Thomas Aquinas believed that God's eternity does not cease, as it is without either a beginning or an end; the concept of eternity is of divine simplicity, thus incapable of being defined or fully understood by humankind.[3]

Thomas Hobbes (1588–1679) and many others in the Age of Enlightenment drew on the classical distinction to put forward metaphysical hypotheses such as "eternity is a permanent now".[4]

Eternity as infinite duration is an important concept in many lives and religions. God or gods are often said to endure eternally, or exist for all time, forever, without beginning or end. Religious views of an afterlife may speak of it in terms of eternity or eternal life.[lower-alpha 2] Christian theologians may regard immutability, like the eternal Platonic forms, as essential to eternity.[5][lower-alpha 3]

Eternity is often symbolized by the endless snake, swallowing its own tail, the ouroboros. The circle, band, or ring is also commonly used as a symbol for eternity, as is the mathematical symbol of infinity, ${\displaystyle \infty }$. Symbolically these are reminders that eternity has no beginning or end.

• Yu, Jiyuan (2003). The Structure of Being in Aristotle's Metaphysics. Springer. pp. 188–. ISBN 9781402015373.

• Entry in the Stanford Encyclopedia of Philosophy on Eternity.
• Entry in the Internet Encyclopedia of Philosophy on the relationship between God and Time.