Know your place in the world and evaluate yourself fairly, not in terms of the naïve ideals of your own youth, nor in terms of what you erroneously imagine your teacher's ideals are.

'Conservation' (the conservation law) means this ... that there is a number, which you can calculate, at one moment-and as nature undergoes its multitude of changes, this number doesn't change. That is, if you calculate again, this quantity, it'll be the same as it was before. An example is the conservation of energy: there's a quantity that you can calculate according to a certain rule, and it comes out the same answer after, no matter what happens, happens.

We scientists are clever — too clever — are you not satisfied? Is four square miles in one bomb not enough? Men are still thinking. Just tell us how big you want it!

If all of this, all the life of a stream of water, can be nothing but a pile of atoms, how much more is possible?

Science is like sex: sometimes something useful comes out, but that is not the reason we are doing it

We have found it of paramount importance that in order to progress, we must recognize our ignorance and leave room for doubt.

It is important to realize that in physics today, we have no knowledge of what energy is