“I still doubt it will work.""You'd doubt the sun's rising if you weren't proven wrong each day," Raoden said with a smile.”

“Doubt thou the stars are fire;Doubt that the sun doth move;Doubt truth to be a liar;But never doubt I love.”

“You wouldn't want to be king of my country," I said. "Why is that?""Well, you're rather fat. I doubt you'd fit onto my throne.”

“I think when one's working, one works between absolute confidence and absolute doubt, and I got a huge dallop of each.”

“Doubt yourself and you doubt everything you see. Judge yourself and you see judges everywhere. But if you listen to the sound of your own voice, you can rise above doubt and judgment. And you can see forever.”

“We did it!" I said, feeling limp with relief. "It actually worked!"Dr. Turgenev rubbed his forehead. "I had very big doubts.""Big doubts?" I said weakly.The Russian scientist shrugged. "I am pessimist," he said.”