Great ideas originate in the muscles.

I start where the last man left off. What the mind of man can conceive and believe, the mind of a man can achieve.

Invention is 1% inspiration and 99% perspiration

To my mind the old masters are not art; their value is in their scarcity.

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

We have merely scratched the surface of the store of knowledge which will come to us. I believe that we are now, a-tremble on the verge of vast discoveries - discoveries so wondrously important they will upset the present trend of human thought and start it along completely new lines .