You can’t say A is made of B or vice versa. All mass is interaction.

Mathematics is a language plus reasoning. It's like a language plus logic. Mathematics is a tool for reasoning.

If all of mathematics disappeared, physics would be set back by exactly one week.

Words can be meaningless. If they are used in such a way that no sharp conclusions can be drawn.

When you're thinking about something that you don't understand, you have a terrible, uncomfortable feeling called confusion... Now, is the confusion's because we're all some kind of apes that are kind of stupid working against this, trying to figure out [how] to put the two sticks together to reach the banana and we can't quite make it... So I always feel stupid. Once in a while, though, the sticks go together on me and I reach the banana.

The inside of a computer is as dumb as hell but it goes like mad!

But see that the imagination of nature is far, far greater than the imagination of man.