Knowledge becomes evil if the aim be not virtuous.

I decided to teach because I think that any person who studies philosophy has to be involved actively.

Imagination is more important than knowledge.

Knowing is not enough; we must apply. Willing is not enough; we must do.

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

The great difficulty in education is to get experience out of ideas.

When I am attacked by gloomy thoughts, nothing helps me so much as running to my books. They quickly absorb me and banish the clouds from my mind.

I like poems you can tack all over with a hammer and there are no hollow places.

Don't learn to do, but learn in doing.

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

Necessity is the mother of invention.

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

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

Don't worry that children never listen to you; worry that they are always watching you.

Education is our passport to the future, for tomorrow belongs to the people who prepare for it today.

Common sense is the collection of prejudices acquired by age eighteen.

The white man is very clever. He came quietly and peaceably with his religion. We were amused at his foolishness and allowed him to stay. Now he has won our brothers, and our clan can no longer act like one. He has put a knife on the things that held us together and we have fallen apart.

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

Just when I thought there wasn't room enough for another thought in my head, I had this great idea.

The most savage controversies are those about matters as to which there is no good evidence either way.

To educate a person in the mind but not in morals is to educate a menace to society.