“We prove what we want to prove, and the real difficulty is to know what we want to prove.”

“The world, somebody wrote, is the place we prove real by dying in it.”

“The non-fiction bestseller lists frequently prove that we all want to know more about everything, even if we didn't know that we wanted to know - we're just waiting for the right person to come along and tell us about it.”

“We do not want a new war. But we are not afraid of it if mobilisation of German power should prove to be the ultimate means of restoring German freedom.”

“You can hire logic, in the shape of a lawyer, to prove anything that you want to prove.”

“First of all, we must cooperate with sincerity. When there are difficulties, that means we have done something others cannot and proves our value.”

“I never tried to prove anything to someone else. I wanted to prove something to myself.”

“She was a nice little girl, simple and true, and tremendously frightened of sex. I told her it was beautiful. I wanted to prove this to her. She let me prove it, but I was too impatient and proved nothing.”

“Once I have gotten into a problem, I find it extremely helpful to get a complete perspective, to learn what earlier scientists thought about it. I want to see not only what lines of thought proved to be productive, but also where and why certain other directions proved to be unproductive.”

“What did we want? We want the world smaller and bigger and just the same but advancing. We don’t know what we want.”