 In "The Lord of the Rings" Tolkien justifies the nature of the Ring by explaining that Elves and other immortal beings dwell in "both worlds" at once (the physical and the spiritual, or Unseen world) and have great power in both, especially those who have dwelt in the light of the Two Trees before the Sun and Moon; and that the powers associated with "magic" were spiritual in nature.Mortals on the other hand are chained to their bodies, have less influence upon them, and their "fëa" depart the world without them.This posed a problem for immortal beings whose spirits do not wane over time, but become increasingly dependent on their physical bodies.