That is the logical tight-rope on which we have to walk if we wish to interpret nature.

In fact the total amount that a physicist knows is very little. He has only to remember the rules to get him from one place to another and he is all right.

People may come along and argue philosophically that they like one better than another; but we have learned from much experience that all philosophical intuitions about what nature is going to do fail.

Study hard what interests you the most in the most undisciplined, irreverent and original manner possible.

I don't feel frightened by not knowing things.

There is nothing in biology yet found that indicates the inevitability of death. This suggests to me that it is not at all inevitable and that it is only a matter of time before biologists discover what it is that is causing us the trouble.

Everybody who reasons carefully about anything is making a contribution ... and if you abstract it away and send it to the Department of Mathematics they put it in books.