The Left Hand of Darkness

'"The unknown," said Faxe's soft voice in the forest, "the unforetold, the unproven, that is what life is based on. Ignorance is the ground of thought. Unproof is the ground of action. If it were proven that there is no God there would be no religion. No Handdara, no Yomesh, no hearthgods, nothing. But also if it were proven that there is a God, there would be no religion... Tell me, Genry, what is known? What is sure, predictable, inevitable - the one certain thing you know concerning your future, and mine?"
"That we shall die."
"Yes. There's really only one question that can be answered, Genry, and we already know the answer... The only thing that makes life possible is permanent, intolerable uncertainty: not knowing what comes next."'

"To be an atheist is to maintain God. His existence or his nonexistence, it amounts to much the same, on the plane of proof. Thus proof is a word not often used among the Handdarata, 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.

To learn which questions are unanswerable, and not to answer them: this skill is most needful in times of stress and darkness."

- Ursula K. Le Guin, The Left Hand of Darkness, Chs. 5 and 11