[236] is that, in examining principles, the word just is misleading. All the virtues are based on experience, physiological or social, and justice is no exception. Just designates a class of rules or principles of which the social utility has been found by experience to be paramount and which are recognized to be so important as to override all considerations of immediate expediency. And social utility is the only test. It is futile, therefore, to say to a Government that it acts unjustly in coercing opinion, unless it is shown that freedom of opinion is a principle of such overmastering social utility as to render other considerations negligible. Socrates had a true instinct in taking the line that freedom is valuable to society.
The reasoned justification of liberty of thought is due to J. S. Mill, who set it forth in his work On Liberty, published in 1859. This book treats of liberty in general, and attempts to fix the frontier of the region in which individual freedom should be considered absolute and unassailable. The second chapter considers liberty of thought and discussion, and if many may think that Mill unduly minimized the functions of society, underrating its claims as against the individual, few will deny the justice of the chief arguments or question the general soundness of his conclusions.
Pointing out that no fixed standard was recognized for testing the propriety of the interference on the part of the community with its individual members, he finds the test in self-protection, that is, the prevention of harm to others. He bases the proposition not on abstract rights, but on utility, in the largest sense, grounded on the permanent interests of man as a progressive being. He then uses the following argument to show that to silence opinion and discussion is always contrary to those permanent interests. Those who would suppress an opinion (it is assumed that they are honest) deny its truth, but they are not infallible. They may be wrong, or right, or partly wrong and partly right. (1) If they are wrong and the opinion they would crush is true, they have robbed, or done their utmost to rob, mankind of a truth. They will say: But we were justified, for we exercised our judgment to the best of our ability, and are we to be told that because our judgment is fallible we are not to use it? We forbade the propagation of an opinion which we were sure was false and pernicious; this implies no greater claim to infallibility than any act done by public authority. If we are to act at all, we must assume our own opinion to be true. To this Mill acutely replies: There is the greatest difference