I did my doctoral thesis on the classical, philosophical proofs for the existence of God. The concept had always intrigued me: "Can you prove that God exists?" After researching the thought of Aquinas, Anselm, Descartes, Leibnitz, and Spinoza (all of whom assert that you can "prove" the existence of God through rational argument) what was the conclusion? Can you prove that God exists?
No, at least not in a way that would compel anyone to make an act faith on the basis of a mathematical or scientific argument. God can't be proven in that way, albeit these "proofs" point to some important things. The existence of God can't be empirically proven because God doesn't work that way. God doesn't appear in the world as the conclusion to a mathematical equation. God, as we know through the way Christ was born, comes into our lives at the end of a gestation process.
That also describes how faith is born in our lives. God never dynamites his way into to our lives with a force so powerful that we can't resist. The divine never takes us by storm. No. God always enters the world in the same way that Jesus did on the first Christmas. God is gestated in a womb and appears as a helpless infant that has to be picked up, nurtured, and coaxed into adulthood. The presence of God in our world, at least within the dynamics of the incarnation, depends upon a certain human consent and cooperation.
For God to take on real flesh and power in the world we must first do something. What? The answer to that lies in the way Jesus was born. Mary, Jesus' mother, shows us a certain blueprint, a pattern for how God is born into our world and how faith is born in our lives. What's the pattern?
When we look at how Mary gave birth to Jesus, we see that there are four moments in the process: Impregnation by the Holy Spirit; gestation of God within one's body and soul; the stretching and agony of giving birth; and the nurturing of an infant into adulthood. What's implied in each of these?
Impregnation by the Holy Spirit: Mary, we are told, became pregnant by the Holy Spirit. What an extraordinary notion! This doesn't just mean that Jesus didn't have a human father, but also that Mary so let the seed of God's spirit (charity, joy, peace, patience, goodness, long–suffering, fidelity, mildness, faith, and chastity) take root in her that it began to grow into actual flesh.
Gestation of God within one's body: As we know, pregnancy is not followed immediately by childbirth. A long, slow process first occurs, gestation. In the silent recesses of her heart and body (and surely not without the normal morning–sickness that accompanies pregnancy) an umbilical cord began to grow between Mary and that new life. Her flesh began to give physical sustenance to the life of God and this steadily grew into a child which, at a point, as in all pregnancies, demanded to be born into the world.
The agony of giving birth: Only with much groaning and stretching of the flesh can a child emerge into this world. It is always excruciatingly painful to birth something to the outside world, to take what's precious inside and give it birth outside. Mary, despite all the over–pious treatises that would make Jesus' birth something unnatural, experienced the normal birth–pains common to all mothers. Nothing secretly gestated is born into the world without pain, Jesus included.
Nurturing an infant into adulthood: Annie Dillard once suggested that we always find God in our lives as Jesus was found in Bethlehem on Christmas, a helpless infant in the straw who must be picked up and nurtured into adulthood: "God's works are as good as we make them. That God is helpless, our baby to bear, self–abandoned on the doorstep of time, wondered at by cattle and oxen." Mary gave birth to the baby, Jesus, but what she ultimately gave the world was the adult, Christ. Like all mothers she had to spend years nursing, cajoling, teaching, and nurturing an infant into adulthood.
In that pattern, the incarnation, in looking at how Mary gave birth to Christ, we are given a blueprint that invites imitation not admiration. Mary is the model of faith. What she did each of us too is called upon to do, namely, give birth to God in our lives. Christmas is for marvelling at what once took place, but it's also for imitation, for continuing to give God flesh in the world.
How do you prove to anyone, yourself included, that God exists? You don't. The object of our faith and worship doesn't appear as a compelling proof at the end of a rational experiment. God has to be gestated into the world in the same way as Mary did all those years ago at the first Christmas.