The relationship of body to soul
Wilbur plays with the question, longstanding in Western philosophy, of whether the soul is separate from or part of the body. In this poem, it is both. On the one hand, the soul is the animating presence, especially of a sleeping form, capable of leaving the body and viewing the scene of angels out the window. In this sense, the soul can see, feel, hear, and speak, as it does in the poem's final stanza. But because the soul seems inseparable from the idea of being awake, alive to the world, it is also a necessary, not an additional, component of the sleeping man. Without the soul, in other words, he doesn't perceive at all; he is dead to the world. It's also worth noting that, although the poem makes extended reference to angels and the soul—historically seen as components of a Christian theology—the poem ultimately returns to the earthly, as opposed to the heavenly. That is, the soul does not so much ascend to heaven as it does take a lesson from the immortal and return with it to earth.
The “truth” of dreams
The soul's perception of the angels in the sky is similar in form to dreaming, which is of course the seeing of visions while sleeping. Although Wilbur does not characterize his vision as a dream, it nevertheless takes an otherworldly event and frames it with the course of a night on earth. Many traditions, of course, exist across cultures for the interpretation of dreams: are they glimpses of the holy, potential lessons for use in waking life, or scenes for psychological excavation? Here, one could imagine answering all three. Wilbur intimates, too, that dreams are at least as "real" as the material reality of sleeping in a bed; though they cannot be touched with the body's organs of sensing, they are nevertheless open to the perception of the soul, which can see, touch, hear.
The mundane vs. the heavenly
Like the division between the soul and the body, the barrier between the earthly and the spiritual worlds plays an important role in the poem. Sleep appears to be one means by which people can access the divine; the soul has no difficulty viewing the angels outside the window. But on closer inspection, the line between human and angelic, earthly and heavenly, becomes less clear, more complex. The angels move with great speed, but they wear the clothes of the earth, and their lessons are easily transferable to the life the man, waking up, realizes he wants to lead. Indeed, the title of the poem indicates that love (the heavenly, rather than romantic, kind) returns humanity to the cares of this present life, rather than to some imagined future.
