POLITICAL PHILOSOPHY There needs protection also against the tyranny of the prevailing opinion and feeling; against the tendency of society to impose, by other means than civil penalties, its own ideas and practices as rules of conduct on those who dissent from them; to fetter the development, and if possible, prevent the formation, of any individuality not in harmony with its ways (L 130) In order to place a just limit on coercion by physical force or public opinion we must affirm, as a fundamental principle, that the only part of the conduct of anyone for which he is accountable to society is that which concerns others In the part which merely concerns himself, his independence should be absolute The most important application of this principle concerns liberty of thought, and the cognate liberties of speaking and writing According to Mill, no authority, autocratic or democratic, has the right to suppress the expression of opinion ‘If all mankind minus one were of one opinion, and only one person were of the contrary opinion, mankind would be no more justified in silencing that one person than he, if he had the power, would be justified in silencing mankind’ (L 130) This is because to suppress an opinion is to rob the whole human race The opinion silenced may, for all we know, turn out to be true, because none of us is infallible If it is not wholly true, it may well contain a portion of truth that would otherwise be neglected Even an opinion that is wholly false has a value as offering a challenge to the contrary opinion and thus ensuring that the truth is not held as a mere prejudice or as a formal profession Freedom of opinion, Mill concludes, and freedom of the expression of opinion, is essential for the mental well-being of mankind But freedom of opinion is not all that is needed Men should be free to act upon their opinions, and to carry them out in their lives, without hindrance, either physical or moral, from their fellows Of course the freedom should not extend to the right to harm others—even freedom of speech must be curtailed in circumstances where the expression of opinion amounts to an incitement to mischief But ample scope should be given to varieties of character and to experiments in living, provided these concern only the individual’s own affairs or the affairs of others ‘with their free, voluntary, and undeceived consent and participation’ The individual’s rule of conduct should be his or her own character, not the traditions or customs of other people If this principle is denied, ‘there is 273