There are children playing in the streets who could solve some of my top problems in physics, because they have modes of sensory perception that I lost long ago.

I need physics more than friends.

In the spring of 1929, I returned to the United States. I was homesick for this country. I had learned in my student days a great deal about the new physics. I wanted to pursue this myself, to explain it, and to foster its cultivation.

It is a profound and necessary truth that the deep things in science are not found because they are useful: they are found because it was possible to find them.

In some sort of crude sense, which no vulgarity, no humor, no overstatement can quite extinguish, the physicists have known sin; and this is a knowledge which they cannot lose.

It is a profound and necessary truth that the deep things in science are not found because they are useful; they were found because it was possible to find them.