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

Real knowledge is to know the extent of one's ignorance.

Necessity is the mother of invention.

To read is to fly: it is to soar to a point of vantage which gives a view over wide terrains of history, human variety, ideas, shared experience and the fruits of many inquiries.

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

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

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

The man who is fond of books is usually a man of lofty thought, and elevated opinions.

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

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.

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

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

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.

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

I had rather excel others in the knowledge of what is excellent, than in the extent of my power and dominion

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

The progressive development of man is vitally dependent on invention.

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

Evil being the root of mystery, pain is the root of knowledge.

It is better to know how to learn than to know.