Richard Feynman

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

"I have no responsibility to have the same opinions that I had a year ago."

"It is better to have loved and lost than never to have loved at all."

"Keep asking why until you reach the fundamental laws of nature."

"The way to success is to do only what you do best."

"What matters is not whether you are right or wrong, but whether you can prove it."

"Perfection is the enemy of improvement."

"The real problem is that we are dealing with an abstraction that has no concrete meaning."

"You must have the confidence to trust your own judgment."

"Nature uses only the longest threads to weave her patterns."

"The best way to understand something is to try to change it."

"There is an iron law of physics: you can't change something without changing something else."

"Pay attention to the details, for they contain the secrets of understanding."

"Do not accept dogma, no matter how authoritative it seems."

"The universe is a complex interplay of simple principles."

"When I undertake to refute my opponent, I hope he will show where I am wrong."

"Responsibility and truth are connected."

"The joy is in the discovery and the understanding."

"Forget what you think you know and look at the evidence."

"An expert is someone who has made every possible mistake in a narrow field."

"Make problems for yourself and see if you can solve them."

"Nature is not only more complex than we imagine, it is more complex than we can imagine."

"The fact that we live at the bottom of a deep gravity well does not mean we are trapped."

"For every situation, you must work out the details."

"Physics is really nothing more than a search for ultimate simplicity."

"Always be prepared to be wrong and happy about it."

"Imagination is more important than knowledge, for knowledge is limited."

"The principle of science is that you do not know anything for sure."

"What you need to work with the same intensity on something that does not pay as much."

"If you cannot understand it, you do not know it well enough."