“I don't know. A proof is a proof. What kind of a proof? It's a proof. A proof is a proof, and when you have a good proof, it's because it's proven.”

“It's good when food tastes good, it's kind of like proof you're alive.”

“Be sceptical, ask questions, demand proof. Demand evidence. Don't take anything for granted. But here's the thing: When you get proof, you need to accept the proof. And we're not that good at doing that.”

“It's gratifying to know that you've appeared in someone else's dreams. It's proof that you exist, in a way, proof that you have substance and value outside the walls of your own mind.”

“One can be enlightened about proofs as well as theorems. Without enlightenment, one is merely reduced to memorizing proofs. With enlightenment about a proof, its flow becomes clear and it can become an item of astonishing beauty. In addition, the need to memorize disappears because the proof has become part of your soul.”

“Absence of proof is not proof of absence.”