Feynman, Richard

"Scientific knowledge is a body of statements of varying degrees of certainty – some most unsure, some nearly sure, none absolutely certain."

"You see, one thing is, I can live with doubt and uncertainty and not knowing. I think it's much more interesting to live not knowing than to have answers that might be wrong."

"The test of all knowledge is experiment. Experiment is the sole judge of scientific truth."

"All the time you're saying to yourself, 'I could do that, but I won't' which is just another way of saying that you can't."

"I wanted very much to learn to draw, for a reason that I kept to myself: I wanted to convey an emotion I have about the beauty of the world."

"The problem is trying to decide what questions are worth answering."

"We are trying to prove ourselves wrong as quickly as possible, because only in that way can we find progress."

"What are the chances that in all the things you think are important, you're right about all of them?"

"The sole test of knowledge is experiment."

"Find something you want to do and do it with all your might."

"It is our nature to need understanding, and that desire will guide us to seek it."

"I think it's much more interesting to live not knowing than to have answers."

"You don't really understand something unless you can explain it to a child."

"It takes intellectual courage to be open to ideas different from your own."

"The world is a very interesting place, and the study of it is worthwhile."

"When you ask people whether they're willing to accept a drug if it's tested in mice, even though there will be side effects, they're not comfortable with it."

"One of the important things is to just look at the system and find out how it works."

"I have approximate answers and possible beliefs and different degrees of certainty about different things."

"The ratio of time you spend reading about something to time you spend reading the actual thing is usually about 10 to 1."

"I learned very young that the answer is always 'I don't know,' and probably no one knows."

"Nature is full of surprise and mystery."

"The most important thing is to not stop questioning."

"I don't know what the answer is, but I know what I'm looking for."

"If I could explain it to the average person, I wouldn't have been worth the Nobel Prize."

"The effort to think clearly is the greatest effort."

"You can't make something that's already broken unbroken."

"I believe that a scientist looking at nonscientific problems is just as dumb as anyone else."

"The way to develop self-confidence is to do the thing you fear."

"We should always be asking: Is this idea true?"

"The happiness of life is made up of small comforts."