The only freedom which deserves the name is that of pursuing our own good in our own way, so long as we do not attempt to deprive others of theirs, or impede their efforts to obtain it. Mankind gains more by suffering each other to live as seems good to themselves than by compelling each to live as seems good to the rest. Coercion in matters of thought and discussion must always be illegitimate. If all mankind save one were of one opinion, mankind would be no more justified in silencing the solitary individual than he, if he had the power, would be justified in silencing mankind. The peculiar evil of silencing the expression of opinion is that it is robbing the whole human race, present and future--those who dissent from the opinion even more than those who hold it. For if the opinion is right, they are deprived of the opportunity of exchanging error for truth; and if wrong, they lose the clear and livelier impression of truth produced by its collision with error. All silencing of discussion is an assumption of infallibility, and, as all history teaches, neither communities nor individuals are infallible. Men cannot be too often reminded of the condemnation of Socrates and of Christ, and of the persecution of the Christians by the noble-minded Marcus Aurelius. Enemies of religious freedom maintain that persecution is a good thing, for, even though it makes mistakes, it will root out error while it cannot extirpate truth. But history shows that even if truth cannot be finally extirpated, it may at least be put back centuries. We no longer put heretics to death; but we punish heresies with a social stigma almost as effective, since it may debar men from earning their bread. Social intolerance does not actually eradicate heresies, but it induces men to hide unpopular opinions. The result is that new and heretical opinions smoulder in the narrow circles of thinking and studious persons who originate them, and never light up the general affairs of mankind with either a true or deceptive light. The price paid for intellectual pacification is the sacrifice of the entire moral courage of the human race. Who can compute what the world loses in the multitude of promising intellects too timid to follow out any bold, independent train of thought lest it might be considered irreligious or immoral? No one can be a great thinker who does not follow his intellect to whatever conclusions it may lead. In a general atmosphere of mental slavery a few great thinkers may survive, but in such an atmosphere there never has been, and never will be, an intellectually active people; and all progress in the human mind and in human institutions may be traced to periods of mental emancipation.