I need physics more than friends.

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.

We judge economics by what it can produce. As such, economics is rather more like engineering than physics: more practical than spiritual.

To try to become happy is to try to build a machine with no other specifications than it shall run noiselessly.

I saw what the Depression was doing to my students. Often they could get no jobs, or jobs which were wholly inadequate. And through them, I began to understand how deeply political and economic events could affect men's lives. I began to feel the need to participate more fully in the life of the community.

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.