The poets have lamented the power of Time to sweep away every object of their love.
Time doth transfix the flourish set on youth, And delves the parallels in beauty's brow, Feeds on the rarities of nature's truth, And nothing stands but for his scythe to mow.
They generally add that their own verses are indestructible:
And yet to times in hope my verse shall stand, Praising thy worth, despite his cruel hand.
But this is only a conventional literary conceit.
Philosophically inclined mystics, unable to deny that whatever is in time is transitory, have invented a conception of eternity as not persistence through endless time, but existence outside the whole temporal process. Eternal life, according to some theologians, for example, Dean Inge, does not mean existence throughout every moment of future time, but a mode of being wholly independent of time, in which there is no before and after, and therefore no logical possibility of change. This view has been poetically expressed by Vaughan:
I saw Eternity the other night, Like a great ring of pure and endless light, All calm, as it was bright; And round beneath it, Time in hours, days, years, Driven by the spheres Like a vast shadow moved; in which the world And all her train were hurled.
Several of the most famous systems of philosophy have tried to state this conception in sober prose, as expressing what reason, patiently pursued, will ultimately compel us to believe.
Heraclitus [the ancient Greek philosopher] himself, for all his belief in change, allowed something everlasting. The conception of eternity (as opposed to endless duration), which comes from Parmenides, is not to be found in Heraclitus, but in his philosophy the central fire never dies: the world "was ever, is now, and ever shall be, an ever-living Fire." But fire is something continually changing, and its permanence is rather that of a process than that of a substance—though this view should not be attributed to Heraclitus.
Science, like philosophy, has sought to escape from the doctrine of perpetual flux by finding some permanent substratum amid changing phenomena. Chemistry seemed to satisfy this desire. It was found that fire, which appears to destroy, only transmutes: elements are recombined, but each atom that existed before combustion still exists when the process is completed. Accordingly it was supposed that atoms are indestructible, and that all change in the physical world consists merely in re-arrangement of persistent elements. This view prevailed until the discovery of radio-activity, when it was found that atoms could disintegrate.
Nothing daunted, the physicists invented new and smaller units, called electrons and protons, out of which atoms were composed; and these units were supposed, for a few years, to have the indestructibility formerly attributed to atoms. Unfortunately it seemed that protons and electrons could meet and explode, forming, not new matter, but a wave of energy spreading through the universe with the velocity of light. Energy had to replace matter as what is permanent. But energy, unlike matter, is not a refinement of the common-sense notion of a "thing"; it is merely a characteristic of physical processes. It might be fancifully identified with the Heraclitean Fire, but it is the burning, not what burns. "What burns" has disappeared from modern physics.
Passing from the small to the large, astronomy no longer allows us to regard the heavenly bodies as everlasting. The planets came out of the sun, and the sun came out of a nebula. It has lasted some time, and will last some time longer; but sooner or later—probably in about a million million years—it will explode, destroying all the planets, and reverting to the condition of a widely diffused gas. So at least the astronomers say; perhaps as the fatal day draws nearer they will find some mistake in their calculations...
The History of Western Philosophy, Bertrand Russell, Chapter 4