All arguments for the existence of God can be classified into two broad categories—cosmological and psychological.  Cosmological arguments take their data from the external world, while psychological arguments start from the evidence we find within ourselves.  One of the more powerful psychological arguments for God’s existence—though less known—is the argument from desire.  That is, the nature of our desire for God seems to provide evidence that God exists. 

THE ARGUMENT FROM DESIRE
Since the data we’re starting with for this argument is our desires, let’s look more closely at our desires.  All of our desires can be divided into two categories.  They are either (1) external, artificial, and conditioned, or they are (2) internal, natural, and universal.  Artificial desires come to us from outside ourselves—from advertising or from society.  We are conditioned to desire them.  Examples might be the desire to fly like Superman, the desire for Santa Clause, the desire to visit Middle Earth, or the desire for the Rockies to win the World Series.   Natural desires are innate to humanity, and therefore universally experienced.  Examples of natural desires might include the desire for drink, food, sleep, love, knowledge, friendship, health, goodness, and beauty.  And different from artificial desires, natural desires have opposites from which we universally retreat and which we all fear—death, loneliness, suffering, pain, evil, ignorance, ugliness.  Artificial desires have no corresponding opposites.  There is no such thing as “Santa Clause-lessness” or Middle Earth-lessness.” 

The next thing we discover from looking at the internal data of our desires is that everything which we naturally and universally desire has a real corresponding object.  We have yet to come across an innate, natural, and universal human desire for a nonexistent object.  Imagine you traveled to another world and discovered a race of beings which had no need of food, and therefore no stomachs for its consumption.  How odd would it be if we then find these no-eating-beings going grocery shopping and watching the cooking channel?  From what we have discovered, for every natural desire there exists an object to satisfy that desire.  This of course says nothing of whether or not we will achieve the object of our natural desires—we may go hungry, lonely, or ignorant.  But it does tell us that such an object exists.  

THE NATURE OF OUR DESIRE FOR GOD
Having realized that all of our natural desires correspond to some real object that can satisfy these desires, we must then look deeply and honestly into our hearts and ask the ultimate question: which of these categories (artificial or natural) does our desire for God fall into?  Is it a desire experienced only within civilized parts of the world, or known as an incident during specific periods of history?  I don’t think so.  It seems to be a human desire of the first category—an internal, natural, and universal desire.  That being the case, we can conclude that there is an object (indeed, the Object) which really exists to satisfy that desire.

AN OBJECTION
Suppose you answer, “I don’t want anything of the angry and petty God of this religion or of that religion.”  Okay, but before you dismiss what I believe is a very powerful argument, ask yourself another question.  Do you naturally desire something so perfect and so beautiful that you cannot really even define it or conceive of it, but you can long for it?  Even if you initially think that you don’t have this sort of desire for God, consider something else.  We all seem to be dissatisfied with this world.  And it’s not just those who don’t have the million dollar amenities.  In fact, it is precisely when we are at our peak experiences of life and are the happiest when we look for more.  We obtain a goal and then question, “Is that it?”  Somehow the achievement is never what we thought it would be.  Why do we say that somehow the chase is better that the achievement—unless there’s something more behind it?

THE LONGING
Is it possible then that this experience throughout life of a continual “longing,” as C. S. Lewis called it, is telling us something about ourselves?  Maybe this natural desire, or at least the universal dissatisfaction with all we’ve experienced in this world, speaks to us of another world.  Perhaps it whispers to us of something greater, something beyond, something other.  Is it conceivable that the good, the true, and the beautiful in this life acts as an echo or appetizer for the supreme essence of Truth, Goodness, and Beauty?

More than any other writer I know of, C. S. Lewis used this argument from desire throughout his writings.  In Mere Christianity he stated it this way:

“Creatures are not born with desires unless satisfaction for these desires exists.  A baby feels hunger; well, there is such a thing as food.  A duckling wants to swim; well, there is such a thing as water.  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 probably explanation is that I was made for another world.” (Bk 3, Ch 10)

GOD & SANTA
I don’t assume that this argument to God from our natural desires is the last word in the matter, but it might be the first for some people.  We still may find someone who ardently claims that he or she simply has no such desire.  While the argument from desire is logically valid, I believe it is intuitively known to be sound and true.  You have the ability to deny the data because the data lies within yourself.  It is something no one else can see.  The power of the argument is for the person who is openly seeking.  But perhaps is can also soften the one who has already concluded that there is no transcendent, personal being of God.  Nevertheless, I think that we’ve at least done away with the repetitive dismissal of God by those who equate the human desire for God with the desire for Santa Clause.  Clearly, the desire for Santa is particular and therefore not universal.

HOW CLOSE TO GOD DID WE GET?
The argument from desire doesn’t get us all the way to the God spoken of in the Bible.  It only gives us a very think slice of who He is.  But it does compel us consider the possibility of there being something or someone who is the “object” of our innate, natural, and universal ultimate desire.  He is the One who we are ultimately longing for in all pursuits, and the One who stands behind all goods.  In his Confessions, Augustine of Hippo laid out the argument in one beautiful sentence: “You have made us for Yourself, O Lord, and our hearts are restless until they rest in You” (Bk 1).