If you feed your mind as often as you feed your stomach, then you'll never have to worry about feeding your stomach or a roof over your head or clothes on your back.

I speak to everyone in the same way, whether he is the garbage man or the president of the university.

Learn from yesterday, live for today.

A large part of our attitude toward things is conditioned by opinions and emotions which we unconsciously absorb as children from our environment. In other words, it is tradition—besides inherited aptitudes and qualities—which makes us what we are. We but rarely reflect how relatively small as compared with the powerful influence of tradition is the influence of our conscious thought upon our conduct and convictions.

Nationalism is an infantile disease. It is the measles of mankind.

He who finds a thought that lets us a little deeper into the eternal mystery of nature has been granted great peace.

The field is the sole influence of the particle.