If you're teaching today what you were teaching five years ago, either the field is dead or you are.

What is freedom of expression? Without the freedom to offend, it ceases to exist.

All stable processes we shall predict. All unstable processes we shall control.

Most people have never learned that one of the main aims in life is to enjoy it.

I cannot live without books.

Many much-learned men have no intelligence.

You can never be overdressed or overeducated.

What is now proved was once only imagined.

Learning never exhausts the mind.

Better know nothing than half-know many things.

Physics is like sex: sure, it may give some practical results, but that's not why we do it.

Any man who reads too much and uses his own brain too little falls into lazy habits of thinking.

In mathematics you don't understand things. You just get used to them.

Opinion is the medium between knowledge and ignorance.

Those who fail to learn the lessons of history are doomed to repeat them.

I am a part of everything that I have read.

Seek knowledge from the cradle to the grave.

Study hard what interests you the most in the most undisciplined, irreverent and original manner possible.

No man's knowledge here can go beyond his experience.

Science is a rising force, It is creating a new world about us. It needs to be watched and pressed into service, and in any case, it would be courting disaster to ignore it.

Just because I don't care doesn't mean I don't understand.