When he said that all mankind has no right to silence one dissenter, he was really affirming that freedom of judgment, the right to be convinced rather than coerced, is an inherent quality of a morally mature personality that a liberal society is one which both acknowledges that right and shapes its institutions in such a way that the right is realized. To permit individuality and private judgment, as if they were tolerated vices, is not enough; a liberal society puts positive value on them as essential to well-being and as marks of a high civilization. The real argument for political freedom, he though, is that it produces and gives scope to a high type of moral character.
To hear public questions freely discussed, to have a share in political decisions, to have moral convictions and to take the responsibility for making them effective are among the ways in which reasonable human beings are produced. The reason for constructing this kind of character is not that it serves an ulterior end but it is an intrinsically human, civilized kind of character. In On Liberty (1859) Mill writes, “If it were felt that the free development of individuality is one of the leasing essentials of well being; that it is not only a coordinate element with all that is designated by the terms civilization, instruction, education, culture, but is itself a necessary part and condition of all these things; there would be no danger that liberty should be undervalue