From his neck down a man is worth a couple of dollars a day, from his neck up he is worth anything that his brain can produce.

I've realized that most of my best ideas have followed a good night's sleep.

Invention is 1% inspiration and 99% perspiration

Success depends on how many experiments you can fit into 24 hours

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

I have not failed 10,000 times. I have succeeded in proving that those 10,000 ways will not work.

My mind is incapable of conceiving such a thing as a soul. I may be in error, and man may have a soul; but I simply do not believe it.