The task of a writer is not to solve the problem but to state the problem correctly.

To every action there is always an equal and opposite or contrary, reaction

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

It is not enough for the teacher to love the child. She must first love and understand the universe. She must prepare herself, and truly work at it.

He who would learn to fly one day must first learn to stand and walk and run and climb and dance; one cannot fly into flying.

Know what you are talking about.

Knowledge is of two kinds. We know a subject ourselves, or we know where we can find information upon it.

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

I cannot live without books.

Science is a way of thinking much more than it is a body of knowledge.

A witty saying proves nothing.

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

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

Science is not only a disciple of reason but, also, one of romance and passion.

A thought is an idea in transit.

When you know better you do better.

In order to stave off covetouness, greed, and spite, citizens world over must be educated.

There is nothing more notable in Socrates than that he found time, when he was an old man, to learn music and dancing, and thought it time well spent.

Books are for people who wish they were somewhere else.

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

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