Anything that won't sell, I don't want to invent. Its sale is proof of utility, and utility is success.

To invent, you need a good imagination and a pile of junk.

Negative results are just what I want. They're just as valuable to me as positive results. I can never find the thing that does the job best until I find the ones that don't.

I find out what the world needs. Then I go ahead and try to invent it.

I am proud of the fact that I never invented weapons to kill.

I make more mistakes than anyone else I know, and sooner or later, I patent most of them.