If we live in a world of uncertainty, then that gives us reason for faith and hope, and to some, poses a viable debate for the existence of a supreme omniscient entity. If we live in a world of possibility and probability where an outcome cannot be predetermined then it means that our existence, which we so often take for granted, has been the result of I don't know how many zillions of uncertain causes and uncertain effects, that have become certain through their occurrence. To many, this is a miracle in itself. We can only reap our existence because everything that has ever happened, happened exactly as it did, and this is reason enough for some to believe in God. If someone were to determine for me every event that were to occur in my life then there would be no reason for me to have hope.
Another argument that one might pose is that they don't just believe in God because of the divine miracle of their existence, but because of their ability to feel, to love, to see, to remember and to have faith in what the future holds. It takes more than a clump of matter to embody such beautiful abilities. That's one way of looking at it...