The juniper-scented liquor had volatilized his thoughts; he should be thinking that madness caused this man to call himself a king, but was thinking … - Ursula K. Le Guin

“The first lesson on Roke, and the last is, Do what is needful! And no more.”
“The lessons in between, then, must consist in learning what is needful.”
“They do.”

"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, unpredictable, 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."

Predictions are uttered by prophets (free of charge); by clairvoyants (who usually charge a fee, and are therefore more honored in their day than prophets); and by futurologists (salaried). Prediction is the business of prophets, clairvoyants, and futurologists. It is not the business of novelists. A novelist’s business is lying.