The best thinking has been done in solitude. The worst has been done in turmoil.

The money one gets for selling one's soul is always spent in deadening one's conscience, so the net gain at the end of a lifetime is no greater than if the diabolic bargain had not been struck.

There is no substitute for hard work.

I did not fail two thousand times. I merely found two thousand ways not to make a lightbulb.

There is no limit to which a man will not go to avoid thinking.

We are striking it big in the electric light, better than my vivid imagination first conceived. Where this thing is going to stop Lord only knows.

Most of my ideas belonged to other people who never bothered to develop them.