There is a sense of romance in the idea that God is the "big great if". Not knowing for sure. Not being able to prove, beyond the shadow of a doubt...to touch, see, feel, hear. Recognizing the limits of reason, the senses, yettrusting. It is the essence of faith, believing without seeing. Like on Polar express, "believing is NOT seeing", in a way. For to see, would take faith out of the equation.