We don't know a millionth of one percent about anything.

I have been at work for some time building an apparatus to see if it is possible for personalities which have left this earth to communicate with us.

The only thing I use my body for is to carry my brain around.

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 never did anything worth doing by accident, nor did any of my inventions come indirectly through accident, except the phonograph. No, when I have, fully decided that a result is worth getting, I go about it, and make trial after trial, until it comes.

The stomach is the only part of man which can be fully satisfied. The yearning of man's brain for new knowledge and experience and for more pleasant and comfortable surroundings never can be completely met. It is an appetite which cannot be appeased.

There is no substitute for hard work.