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

I try not to invent things that people don't need.

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

My main purpose in life is to make money so I can afford to go on creating more inventions.

The greatest invention in the world is the mind of a child.

I never did anything by accident, nor did any of my inventions come by accident; they came by work.