[For people] to refuse a hearing to an opinion, because they are sure that it is false, is to assume that their certainty is the same thing as absolu… - John Stuart Mill

All silencing of discussion is an assumption of infallibility.

The liberty of the individual must be thus far limited, he must not make himself a nuisance to other people.

He who knows only his own side of the case, knows little of that. His reasons may be good, and no one may have been able to refute them. But if he is equally unable to refute the reasons on the opposite side; if he does not so much as know what they are, he has no ground for preferring either opinion.

Society can and does execute its own mandates: and if it issues wrong mandates instead of right, or any mandates at all in things with it ought not to meddle, it practices a social tyranny more formidable than many kinds of political oppression, since, though not usually upheld by such extreme penalties, it leaves fewer means of escape, penetrating much more deeply into the details of life, and enslaving the soul itself.