You can know the name of a bird in all the languages of the world, but when you're finished, you'll know absolutely nothing whatever about the bird... So let's look at the bird and see what it's doing -- that's what counts.

To test whether you have learned an idea or a definition, rephrase what you just learned without using the new word.

Why make yourself miserable saying things like, "Why do we have such bad luck? What has God done to us? What have we done to deserve this?" - all of which, if you understand reality and take it completely into your heart, are irrelevant and unsolvable. They are just things that nobody can know. Your situation is just an accident of life.

But the real glory of science is that we can find a way of thinking such that the law is evident.

I was born not knowing and have had only a little time to change that here and there.

The present situation in physics is as if we know chess, but we don't know one or two rules.

[B]eyond poverty, beyond the point that the material needs are reasonably satisfied, only from within is peace.