The deepest sin against the human mind is to believe things without evidence.

What is now proved was once only imagined.

The only true wisdom is in knowing you know nothing.

It isn't what we don't know that gives us trouble, it's what we know that ain't so.

Knowledge becomes evil if the aim be not virtuous.

A thought is an idea in transit.

The ability to observe without evaluating is the highest form of intelligence.

If I could explain it to the average person, I wouldn't have been worth the Nobel Prize.

There is nothing more awful, insulting, and depressing than banality.

God created man in His own image, says the Bible; philosophers reverse the process: they create God in theirs.

My weapon is literature

The reading of all good books is like conversation with the finest men of past centuries.

There is one quality which one must possess to win, and that is definiteness of purpose, the knowledge of what one wants, and a burning desire to possess it.

Study without desire spoils the memory, and it retains nothing that it takes in.

I have just three things to teach: simplicity, patience, compassion. These three are your greatest treasures.

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

Men are born ignorant, not stupid. They are made stupid by education.

It is what you read when you don't have to that determines what you will be when you can't help it.

The schools ain't what they used to be and never was.

Courage, conviction and confidence.

The first principle is that you must not fool yourself and you are the easiest person to fool.