Feynman, Richard

"Nothing is really learned until you experience it yourself."

"The probability of something happening a second time is much higher."

"If we knew what it was we were doing, it would not be called research."

"I learned to observe, and that is how I got all my physics."

"Cargo cult science is science conducted with all the outward forms and expressions that are dressy but actually lacks the inner substance."

"The most exciting phrase to hear in science is not 'Eureka!' but 'That's funny...'"

"You have to keep a sense of humor about it."

"Try to stay young while you're learning, and keep learning after you're old."

"First principles: don't fool yourself, and you are the easiest person to fool."

"It's a hell of a problem when you want to do something and you don't know how."

"Seek out people who disagree with you."

"The stage of life where we are not learning is the stage of dying."

"I think that it is much more interesting to live not knowing than to have answers that might be wrong."

"The reason we have to read history is that it contains models of various kinds of human experience that we cannot hope to have in our actual life."

"It doesn't matter whether you make the effort to change your life or not – the effort itself is what counts."

"To understand something is to be satisfied with it."

"We are not responsible for what we are taught; we are responsible for ourselves."

"The pleasure of finding things out is one of the greatest joys."

"Being a scientist is a way of thinking, not just a collection of facts."

"Learn to say 'I don't know' and listen to those who do."

"The more you learn, the more you realize you don't know."

"Everything that is going to be done has to start with an idea."

"There is a time to think and a time to act."

"The most important thing in science is to find the order in nature."

"I have a very simple motto that has helped me throughout my life: 'Have fun doing it.'"

"Authority is not a source of truth."

"Principles are things you can lean on."

"When you get to be my age, you realize you are not going to live forever."

"What we learned before is often incorrect and we need to adjust."

"You must forget about the plan and think of the essence."