While there are many who claim not to believe in God, my guess is that most of them wish they could believe in a God. Consider these words, respectively, from Somerset Maugham (The Summing Up) and Jean-Paul Sarte (Nausea):
“If one puts aside the existence of God and the survival after life as too doubtful…one has to make up one’s mind as to the use of life. If death ends all, if I have neither to hope for good nor to fear evil, I must ask myself what I am here for, and how in these circumstances I must conduct myself. Now the answer is plain, but so unpalatable that most will not face it. There is no meaning for life, and [thus] life has no meaning.” – Somerset Maugham
“It was true, I had always realized it – I hadn’t any ‘right’ to exist at all. I had appeared by chance, I existed like a stone, a plant, a microbe. I could feel nothing to myself but an inconsequential buzzing. I was thinking…that here we are eating and drinking, to preserve our precious existence, and that there’s nothing, nothing, absolutely no reason for existing.” - Jean-Paul Sarte
I must confess that I think from a more-or-less Christian viewpoint and I realize that many in this world can’t understand my way of thinking about life and purpose and meaning. Still, who would rather opt for the mindset of Maugham or Sarte? Who wants to live a life of absolute, sub-zero emptiness without any reason?
It is true that no one can “prove” God’s existence. I suppose that on the day He returns, there will still be those who will try to deny the Reality with which they are confronted – thinking that it is the product of some strange chemical reaction in their mind. But it won’t be. It will be real – HE will be real. While we can prove the existence of what we call oxygen and hydrogen, we can’t prove the existence of the soul, nor of the Divine.
Once more, I think C.S. Lewis can be informative for us when it comes to God’s existence. He said, “…as I believe the sun has risen, not only because I see it, but because by it I see everything else.” Timothy Keller, in The Reason for God, continued: “Imagine trying to look directly at the sun in order to learn about it. You can’t do it. It will burn out your retinas, ruining your capacity to take it in. A far better way to learn about the existence, power, and quality of the sun is to look at the world it shows you, to recognize how it sustains everything you see and enables you to see it….We should not try to ‘look into the sun,’ as it were, demanding irrefutable proofs for God. Instead we should look “at what the sun shows us.” —Galen Dalrymple