First, if any opinion is compelled to silence, that opinion may, for aught we can certainly know, be true. To deny this is to assume our own infallib… - John Stuart Mill

Then are seen the cases, so frequent in this age of the world as almost to form the majority, in which the creed remains as it were outside the mind, incrusting and petrifying it again all other influences addressed to the higher parts of our nature; manifesting its power by not suffering any fresh and living conviction to get in, but itself doing nothing for the mind or heart except standing sentinel over them to keep them vacant

Judgment is given to men that they may use it. Because it may be used erroneously, are men to be told that they ought not to use it at all? To prohibit what they think pernicious is not claiming exemption from error, but fulfilling the duty incumbent on them, although fallible, of acting on their conscientious conviction. If we were never to act on our opinions, because those opinions ‘lay be wrong, we should leave all our interests uncared for, and all our duties unperformed. An objection which applies to all conduct can be no valid objection to any conduct in particular.

Civil, or Social Liberty: the nature and limits of the power which can be legitimately exercised by society over the individual.