642 Quotes by Richard P. Feynman

Unless a thing can be defined by measurement, it has no place in a theory. And since an accurate value of the momentum of a localized particle cannot be defined by measurement it therefore has no place in the theory.

I learned from her that every woman is worried about her looks, no matter how beautiful she is.

When I would hear the rabbi tell about some miracle such as a bush whose leaves were shaking but there wasn't any wind, I would try to fit the miracle into the real world and explain it in terms of natural phenomena.

The theoretical broadening which comes from having many humanities subjects on the campus is offset by the general dopiness of the people who study these things ...

Everything we know is only some kind of approximation, because we know that we do not know all the laws yet. Therefore, things must be learned only to be unlearned again or, more likely, to be corrected.

With the exception of gravitation and radioactivity, all of the phenomena known to physicists and chemists in 1911 have their ultimate explanation in the laws of quantum electrodynamics.

Progress in science comes when experiments contradict theory.

The test of all knowledge is experiment.

You should not fool the laymen when you're talking as a scientist... . I'm talking about a specific, extra type of integrity that is not lying, but bending over backwards to show how you're maybe wrong, [an integrity] that you ought to have when acting as a scientist. And this is our responsibility as scientists, certainly to other scientists, and I think to laymen.