The only purpose for which power can be rightfully exercised over any member of a civilized community, against his will, is to prevent harm to others. His own good, either physical or moral, is not sufficient warrant.

There are many truths of which the full meaning cannot be realized until personal experience has brought it home.

The price paid for intellectual pacification is the sacrifice of the entire moral courage of the human mind.

...there ought to exist the fullest liberty of professing and discussing, as a matter of ethical conviction, any doctrine, however immoral it may be considered.

The idea that truth always triumphs over persecution is one of those pleasant falsehoods, which most experience refutes. History is teeming with instances of truth put down by persecution. If not put down forever, it may be set back for centuries.

Among the facts of the universe to be accounted for, it may be said, is Mind; and it is self evident that nothing can have produced Mind but Mind.

But these few are the salt of the earth; without them, human life would become a stagnant pool. Not only is it they who introduce good things which did not before exist, it is they who keep the life in those which already existed.