Every honest researcher I know admits he's just a professional amateur. He's doing whatever he's doing for the first time. That makes him an amateur. He has sense enough to know that he's going to have a lot of trouble, so that makes him a professional.

The only time you mustn't fail is the last time you try.

It is the 'follow through' that makes the great difference between ultimate success and failure, because it is so easy to stop.

An inventor fails 999 times, and if he succeeds once, he's in. He treats his failures simply as practice shots.

Keep on going and the chances are you will stumble on something, perhaps when you are least expecting it. I have never heard of anyone stumbling on something sitting down.

We have a lot of people revolutionizing the world because they've never had to present a working model.

A research problem is not solved by apparatus; it is solved in a man's head.