642 Quotes by Richard P. Feynman

To test whether you have learned an idea or a definition, rephrase what you just learned without using the new word.

A scientist is never certain. ... We absolutely must leave room for doubt or there is no progress and there is no learning.

Our poets do not write about it; our artists do not try to portray this remarkable thing. I don't know why. Is nobody inspired by our present picture of the universe? The value of science remains unsung by singers... This is not yet a scientific age...

Scientific knowledge is an enabling power to do either good or bad — but it does not carry instructions on how to use it.

It has been discovered that all the world is made of the same atoms, that the stars are of the same stuff as ourselves. It then becomes a question of where our stuff came from. Not just where did life come from, or where did the earth come from, but where did the stuff of life and of the earth come from?

Poets say science takes away from the beauty of stars-mere globs of gas atoms. Nothing is "mere". I too see the stars on a desert night, and feel them. But do I see less or more? ...What is the pattern, or the meaning, or the why? It does not do harm to the mystery to know a little more about it. For far more marvelous is the truth than any artists of the past imagined it.

The electron is a theory. But the theory is so good we can almost consider them real.

The highest forms of understanding we can achieve are laughter and human compassion.

The extreme weakness of quantum gravitational effects now poses some philosophical problems; maybe nature is trying to tell us something new here: maybe we should not try to quantize gravity.