“… That unnameable something, desire for which pierces us like a rapier at the smell of a bonfire, the sound of wild ducks flying overhead, the title of The Well at the World’s End, the opening lines of Kubla Khan, the morning cobwebs in late summer, or the noise of falling waves?
It appeared to me therefore that if a man diligently followed this desire, pursuing the false objects until their falsity appeared and then resolutely abandoning them, he must come out at last into the clear knowledge that the human soul was made to enjoy some object that is never fully given–nay, cannot even be imagined as given–in our present mode of subjective and spatio-temporal experience. This Desire was, in the soul, as the Siege Perilous in Arthur’s castle–the chair in which only one could sit. And if nature makes nothing in vain, the One who can sit in this chair must exist. I knew only too well how easily the longing accepts false objects and through what dark ways the pursuit of them leads us: but I also saw that the Desire itself contains the corrective of all these errors. The only fatal error was to pretend that you had passed from desire to fruition, when, in reality, you had found either nothing, or desire itself, or the satisfaction of some different desire. The dialectic of Desire, faithfully followed, would retrieve all mistakes, head you off from all false paths, and . . . to propound, but to live through, a sort of ontological proof. This lived dialectic, and the merely argued dialectic of my philosophical progress, seemed to have converged on one goal; accordingly I tried to put them both into my allegory which thus became a defence of Romanticism (in my peculiar sense) as well as of Reason and Christianity.”
~ C.S. Lewis, From the Preface to Pilgrim’s Regress
Along this vein, I just started an awesome book on Lewis’ notion of Sehnsucht, Corbin Scott Carnell’s Bright Shadow of Reality: Spiritual Longing in C. S. Lewis. It is really intriguing so far; you can buy it here.