I believe that the motion picture is destined to revolutionize our educational system and that in a few years it will supplant largely, if not entirely, the use of textbooks.

I am both pleased but astonished by the fact that mankind has not yet begun to use all the means and devices that are available for destruction. I hope that such weapons are never manufactured in quantity.

The reason a lot of people do not recognize opportunity is because it usually goes around wearing overalls looking like hard work.

There is a better way for everything. Find it.

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.

Many a person who could not comprehend Rousseau, and would be puzzled by Montesquieu, could understand Paine as an open book. He wrote with a clarity, a sharpness of outline and exactness of speech that even a schoolboy should be able to grasp.

I am afraid of radium and polonium ... I don't want to monkey with them.