The Burden of Immortality

One of the more subtle points of Tolkein's Lord of the Rings mythos is that immortality as experienced by the Elves and other nonhuman creatures is immortality "within the world." The inhabitants of the Undying Lands of Valinor and the dead who wait in the Halls of Mandos are alike confined to the world, and when Iluvatar, the Creator, ends the world, they will end with it. To Tolkein, the Gift to Men was the ability to die in truth and to leave the world.

This has obvious connections with Christian theology. There is also a parallel with the Buddhist idea of the Wheel of Life, wherein one is reincarnated over and over, as human or god or demon or animal, in the world or heaven or hell or purgatory, and cannot escape this cycle except through the Enlightenment by which one leaves the Wheel.

The living can experience something analogous to eternal life unchanging. As the result of head trauma, some people receive a kind of brain damage that prevents them from converting short-term into long-term memories. Such a person lives in an eternal present. Every day is new; every other person, a stranger. Every day their own condition is something to deny, rage against, bargain about, and painfully accept, all over again.

From a certain point of view, immortality is not a gift at all, but a curse. Imagine spending eternity unable to escape from yourself; unable to escape from pleasures and pains experienced to surfeit; unable to learn, change, or grow.

The idea of Hell is inherent in the idea of eternal life unchanging.