If every man possessed everything he wanted, and no one had the power to interfere with such possession; or if no man desired thatwhich could damage his fellow-man, justice would have no part to play in the universe.

No slavery can be abolished without a double emancipation, and the master will benefit by freedom more than the freed-man.

The ultimate court of appeal is observation and experiment... not authority.

Sit down before fact as a little child, be prepared to give up every conceived notion, follow humbly wherever and whatever abysses nature leads, or you will learn nothing.

Trust a witness in all matters in which neither his self-interest, his passions, his prejudices, nor the love of the marvellous is strongly concerned. When they are involved, require corroborative evidence in exact proportion to the contravention of probability by the thing testified.

Tolerably early in life I discovered that one of the unpardonable sins, in the eyes of most people, is for a man to go about unlabeled. The world regards such a person as the police do an unmuzzled dog.

You may read any quantity of books, and you may almost as ignorant as you were at starting, if you don't have, at the back of yourminds, the change for words in definite images which can only be acquired through the operation of your observing faculties on the phenomena of nature.