God.

person A: Do you beleive in God?

person B: No. But why?

person A: Because you see, God- whatever anyone chooses to call God- is one's highest conception of the highest possible. And whoever places his highest conception above his own possibility thinks very little of himself and his life.
It's a rare gift you know, to feel reverence for your own life, and to want the best, the greatest, the highest possible, here , now, for your very own. To imagine a heaven, and then not to dream of it , but to demand it.

.....................................Ayn Rand...............................We, The Living.......................................................