It is possible to fly without motors, but not without knowledge and skill.

The delight of opening a new pursuit, or a new course of reading, imparts the vivacity and novelty of youth even to old age.

Any knowledge that doesn't lead to new questions quickly dies out: it fails to maintain the temperature required for sustaining life.

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

I learned very early the difference between knowing the name of something and knowing something.

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

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

I am a part of everything that I have read.

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

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

Human behavior flows from three main sources: desire, emotion, and knowledge

A thought is an idea in transit.

Education is an admirable thing, but it is well to remember from time to time that nothing that is worth knowing can be taught.

No power and no treasure can outweigh the extension of our knowledge.

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

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

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

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

Investigate, educate and organize.

Opinion is the medium between knowledge and ignorance.

The man who does not read good books has no advantage over the man who can't read them.