If free opinion matters, Mill argues, the same reasons require freedom to act upon opinions and to carry them into life without hindrance from others, so long as the agent bears the risk. Liberty of action is never absolute: a person must not make himself a nuisance, and society may control harmful acts by unfavorable sentiment or, when necessary, active interference. His famous corn-dealer case makes the line concrete. Saying in print that corn-dealers starve the poor may be protected, but shouting the same charge to an excited mob outside a dealer's house is a positive instigation to harm and may be punished even when the printed words would be lawful. Where conduct concerns only the agent, however, society should allow experiment. The reasons for tolerating contrary opinions apply to contrary ways of acting: while mankind are imperfect, diversity of practice is as valuable as diversity of belief because no single pattern contains the whole of life.
Individuality is not ornament but an element of well-being. A person who lets the world, or his own portion of it, choose his plan of life needs little beyond imitation; one who chooses for himself must use observation, reasoning, judgment, activity, and self-control in proportion to the ground he claims for his own decisions. It matters not only what people do but what manner of persons they are while doing it. Human nature is not a machine to be built after a model and set to prescribed work, but a tree that must grow and develop on all sides according to inward forces. Mill grants that intelligent adherence to custom beats blind mechanical conformity, yet society treats strong desires and impulses as perils while praising characters trained to renounce spontaneity. Calvinism, in strict or softened form, demands that people live for an external will rather than their own energies; Mill answers with a Greek ideal of self-development joined to Christian self-restraint. Pagan self-assertion and disciplined self-denial both belong to human excellence; the goal is not to wear individuality down into uniformity but to cultivate it within the limits imposed by others' rights.
Originality, genius, and even eccentricity keep life from freezing. Genius in thought and action opens eyes that could not otherwise see new possibilities, yet nearly everyone professes admiration while resenting deviation in practice. Unoriginal minds cannot feel the use of originality until it has already changed the landscape. In politics and social life, individuals are lost in crowds; mediocrity becomes ascendant power. People tolerate tastes shared by large numbers, such as rowing, smoking, chess, or study, because neither side can be suppressed. Yet society reserves its fiercest pressure for the person whose way of life cannot recruit a party large enough to make coercion embarrassing. But the man, and still more the woman, who does what nobody does or omits what everybody does faces depreciatory judgment as if a grave moral fault had been committed unless rank or wealth grants indulgence. In an age of improving manners and philanthropic reform, public opinion grows especially intolerant of marked individuality, because average people, moderate in intellect and desire, do not understand those with stronger inclinations and class all intensity as wildness.
Mill insists that different experiments in living are needed because human beings are not copies of one another. They require different conditions for happiness and different outlets for energy; unless modes of life can diversify, persons neither obtain their fair share of happiness nor reach the stature their nature allows. That is why suppressing self-regarding difference is not merely unkind but socially stupid. Strong impulses, when cultivated rather than crushed, produce energy and depth; weak characters trained only to copy external standards are the greater loss. Eccentricity looks wasteful until it reveals a path others can borrow, because every valuable practice was once the project of someone who refused the common pattern. Europe's progress, he argues, came from remarkable diversity among individuals, classes, and nations, each trying paths others condemned yet could not permanently destroy. China offers the counter-image: a civilization early possessed of sages, examinations, and powerful machinery for impressing approved wisdom on every mind, which succeeded in making people alike and then remained stationary for thousands of years, improved only when foreigners supplied what conformity could not generate. The modern regime of public opinion is, in unorganized form, what Chinese education and politics are in organized form. Unless individuality can assert itself against that yoke, Europe, for all its Christianity and classical inheritance, will tend toward another China. The despotism of custom already punishes self-regarding nonconformity more sharply than many former laws punished political crime. Mill ends by insisting that spontaneity, choice, and experiments in living are not luxuries for the gifted few but conditions under which ordinary persons become fully human rather than copies of a single approved model.
