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.

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.

Learn how to fail intelligently.

Great steps in human progress are made by things that don't work the way philosophy thought they should. If things always worked the way they should, you could write the history of the world from now on. But they don't, and it is those deviations from the normal that make human progress.

The person who doesn't know something can't be done will often find a way to go ahead and do it.

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

I am not interested in the past. I am interested in the future, for that is where I expect to spend the rest of my life.