Eternity
Eternity in common parlance means the infinite time that never ends (or the quality, condition, or fact of being eternal). In classical philosophy, however, it is defined as what exists outside time as describing supranatural beings and forces, whereas sempiternity corresponds to the infinitely temporal, non-metaphoric definitions, as recited in requiem prayers for the dead. Thomas Hobbes 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”.
Eternity as infinite duration is an important concept in many religions, where the god or gods are said to endure eternally. Some, such as Aristotle, would say the same about the natural cosmos in regard to both past and future eternal duration, and like the eternal Platonic forms, immutability was considered essential. Today cosmologists, philosophers, and others look to analyses of the concept from across cultures and history. They debate, among other things, whether an absolute concept of eternity has real application such for the fundamental laws of physics such as the arrow of time in entropy.
Infinity Symbol
Philosophy
See also: Philosophy of space and time
Aristotle argued that the cosmos has no beginning. In Aristotle’s Metaphysics, eternity is the unmoved mover (God), understood as the gradient of total synergy (“produces motion by being loved”). Boethius defined eternity as “simultaneously full and perfect possession of interminable life”.
Symbolism
See also: Engagement ring, eternity ring, and wheel of time
Eternity is often symbolized by the endless snake, swallowing its own tail, the ouroboros (or oroboros). The circle, band or ring is also commonly used as a symbol for eternity, as is the mathematical symbol of infinity, 
. Symbolically these are reminders that eternity has no beginning/end.
 infinity symbols |
 Endless Knot, Auspicious Symbol – Mongolia |
 One common form of the Endless Knot |
God and Eternity
Main article: God and eternity
The idea of eternity as it relates to God is an important concept in theology. Theists say that God is eternally existent. How this is understood depends on which definition of eternity is used. On one hand, God may exist in eternity. One other definition states that God exists outside the human concept of time, but also inside of time.
Death and Eternity
Main article: Death and Eternity
Man has an intrinsic feeling of eternity; he feels imprisoned in the narrow confines of the material world and always yearns for eternity. Whoever hearkens to man’s conscious nature will hear it pronouncing eternity over and over again. If a man were given the whole universe, it would not compensate him for his ‘hunger’ for eternal life, for which he was created. This natural inclination of man toward eternal happiness comes from an objective reality, which is the existence of an eternal life and man’s desire for it.
See also
Adapted from Wikipedia, the free encyclopedia