Experiment is the sole judge of the validity of any idea.

The exception tests the rule.

If all of mathematics disappeared, physics would be set back by exactly one week.

The female mind is capable of understanding analytic geometry... The difficulty may just be that we have never yet discovered a way to communicate with the female mind. If it is done in the right way, you may be able to get something out of it.

There is one simplification at least. Electrons behave ... in exactly the same way as photons; they are both screwy, but in exactly in the same way.

The electron is a theory we use; it is so useful in understanding the way nature works that we can almost call it real.

You can’t say A is made of B or vice versa. All mass is interaction.