Richard P. Feynman

Quotes

1. In general, we look for a new law by the following process: First we guess it. Then we – now don't laugh, that's really true. Then we compute the consequences of the guess to see what, if this is right, if this law that we guessed is right, to see what it would imply. And then we compare the computation results to nature, or we say compare to experiment or experience, compare it directly with observations to see if it works. If it disagrees with experiment, it's wrong. In that simple statement is the key to science. It doesn't make any difference how beautiful your guess is, it doesn't make any difference how smart you are, who made the guess, or what his name is. If it disagrees with experiment, it's wrong. That's all there is to it.

2. 

   [O]ne additional problem.., which took twenty years to overcome.., has to do with ideal electrons and photons and the numbers n and j.

   If electrons were ideal and went... only by... direct path..: n would... be the [electron] mass.., and j its "charge" (the amplitude for the electron to couple with the photon).

   But no... ideal electrons exist.

   p. 125

3. 

   chapter 2, “The Relation of Mathematics to Physics,” p. 58; video

4. 

   Mathematics is not just a language. Mathematics is a language plus reasoning. It's like a language plus logic. Mathematics is a tool for reasoning. It's, in fact, a big collection of the results of some person's careful thought and reasoning. By mathematics, it is possible to connect one statement to another.

5. 

   The next question was — what makes planets go around the sun? At the time of Kepler some people answered this problem by saying that there were angels behind them beating their wings and pushing the planets around an orbit. As you will see, the answer is not very far from the truth. The only difference is that the angels sit in a different direction and their wings push inward.

   p. 18

6. 

   It is impossible, by the way, when picking one example of anything, to avoid picking one which is atypical in some sense.

   p. 27

7. 

   [I]nstead of including all... coupling points to... distance... zero, if one stops the calculation when the distance is very small... billions of times smaller than anything observable... (presently 10-16 centimeters)... there are definite values... n and j... so the calculated mass... match the m observed... and the calculated charge matches the observed... e. ...[T]he catch: if somebody... stops the calculation at a different distance... their... n and j come out different!

   p. 127

8. 

   ...Dirac discovered the correct laws for relativity quantum mechanics simply by guessing the equation. The method of guessing the equation seems to be a pretty effective way of guessing new laws. This shows again that mathematics is a deep way of expressing nature, and any attempt to express nature in philosophical principles, or in seat-of-the-pants mechanical feelings, is not an efficient way.

   ...It always bothers me that, according to the laws as we understand them today, it takes a computing machine an infinite number of logical operations to figure out what goes on in no matter how tiny a region of space, and no matter how tiny a region of time. How can all that be going on in that tiny space? Why should it take an infinite amount of logic to figure out what one tiny piece of space/time is going to do? So I have often made the hypotheses that ultimately physics will not require a mathematical statement, that in the end the machinery will be revealed, and the laws will turn out to be simple, like the chequer board with all its apparent complexities.

9. 

   People are always asking for the latest developments in the unification of this theory with that theory, and they don't give us a chance to tell them anything about what we know pretty well. They always want to know the things we don't know.

   p. 3

10. 

    You will have to brace yourselves for this — not because it is difficult to understand, but because it is absolutely ridiculous: All we do is draw little arrows on a piece of paper — that's all!

    p. 24

11. 

    Therefore psychologically we must keep all the theories in our heads, and every theoretical physicist who is any good knows six or seven different theoretical representations for exactly the same physics.

    p. 168

12. 

    The theory of quantum electrodynamics describes Nature as absurd from the point of view of common sense. And it agrees fully with experiment. So I hope you accept Nature as She is — absurd.

    p. 10