Lewis’s point is that there are desires for many things in this world. In his apologetic works, he discusses at length man’s desire for food, for rest, for companionship, for beauty, for enlightenment. He says, however, that those desires do not function in and of themselves. Rather, they are used as proofs by God to ensure us that, just as we desire food and there is food to fulfill that desire, there is also a God with whom we long to unite that will, when we ask Him, come down and fellowship with us in a way that will meet our every longing for Him. “Creatures are not born with desires unless satisfaction for desires exists. A baby feels hunger; well, there is such a thing as food…. Men feel sexual desire; well, there is such a thing as sex. If I find in myself a desire which no experience in this world can satisfy, the most probable explanation is that I was made for another world” (Lewis, Mere Christianity). God created us with desires that can be fulfilled temporally in order to give us hope that those desires that cannot be fulfilled temporally will be fulfilled eternally. Our Creator desires for us to know that that we were not created with a desire that will not be fulfilled, and Lewis’s argument that since all temporal desires are fulfilled, then even those desires that we have not yet found fulfillment for will one day be fulfilled.
When looking to the Bible for confirmation of Lewis’s argument, one can look to Hebrews 11:13-16 where the writer speaks of those in the Old Testament who were highly esteemed for their faith in an unseen fulfillment of their desires:
All these people were still living by faith when they died. They did not receive the things promised; they only saw them and welcomed them from a distance. And they admitted that they were aliens and strangers on earth. People who say such things show that they are looking for a country of their own. If they had been thinking of the country they had left, they would have had opportunity to return. Instead, they were longing for a better country—a heavenly one (emphasis mine).
Even upon their death, these great men and women of faith had not received the things promised to them. Their desires had not been fulfilled. And rightly so, Lewis would argue, for who would want to place their faith for eternity in a longing fulfilled in this life? He, for one, did not. “Every step I had taken, from the Absolute to ‘Spirit’ and from ‘Spirit’ to ‘God,’ had been a step toward the more concrete, the more imminent, the more compulsive” (Lewis, Surprised by Joy, 237). When it comes right down to it, all anyone in this world is looking for is something sure in which to place their trust. What could be more trustworthy than a God who has ensured that everyday we will experience small confirmations of His constant presence both here and in the hereafter?