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

Science is what we have learned about how to keep from fooling ourselves.

Suddenly degrees aren't worth anything. Isn't that true? When I was a student, if you had a degree, you had a job. If you didn't have a job it's because you didn't want one. And I didn't want one, frankly.

We could never learn to be brave and patient, if there were only joy in the world

Although modesty is natural to man, it is not natural to children. Modesty only begins with the knowledge of evil.

If help and salvation are to come, they can only come from the children, for the children are the makers of men.

Seek knowledge from the cradle to the grave.

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

As we acquire more knowledge, things do not become more comprehensible but more mysterious.

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

If you can't explain it simply, you don't understand it well enough.

Necessity is the mother of invention.

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

The books that the world calls immoral are books that show the world its own shame.

Real learning comes about when the competitive spirit has ceased.

The real solution lies in a world in which charity will have become unnecessary.

The progressive development of man is vitally dependent on invention.

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

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

Reading is to the mind what exercise is to the body.

Education is the ability to listen to almost anything without losing your temper or your self-confidence.