From Ursula K. LeGuin, from her science fiction novel The Left Hand of Darkness:
“To be an atheist is to maintain God. His [sic] existence or his non-existence, it amounts to much the same, on the plane of proof. Thus ‘proof’ is a word not often used among the Handarata, who have chosen not to treat God as a fact, subject either to proof or to belief: and they have broken the circle, and go free.”