Reading On Liberty

On Liberty is the clearest defense ever written of the freedom to be wrong. John Stuart Mill set out to answer a question that every free society has to keep answering: how much power may the community rightly exercise over the individual? His answer, compressed into what became known as the harm principle, is one of the most consequential sentences in political philosophy, and it remains the starting point for nearly every serious argument about freedom of speech and conduct.

The principle is this: the only purpose for which power can be rightfully exercised over any member of a civilized community, against their will, is to prevent harm to others. A person's own good, physical or moral, is not a sufficient warrant. Over themselves, over their own body and mind, the individual is sovereign. You may argue with people, reason with them, plead with them, but you may not coerce them merely because you think it would be good for them, or because their choices offend you.

That line, between actions that harm others and actions that concern only oneself, does enormous work and is endlessly contested at the edges. But its core is a radical and durable claim: that a free society must leave people a wide zone of liberty to live as they see fit, including the liberty to make choices the majority considers foolish or wrong, so long as they are not harming others.

Mill's defense of free speech is the part most worth reading today. He argues for tolerating even opinions we are certain are false, on grounds that go beyond mere politeness. If a silenced opinion is true, we lose the chance to exchange error for truth. If it is false, we lose something almost as valuable, the clearer perception of truth produced by its collision with error. And if it is partly true, as contested opinions usually are, only the clash of views lets the partial truths combine. An opinion never challenged, he warns, becomes a dead dogma rather than a living truth, held as prejudice rather than understood as conviction.

This is the deep case for free expression: not that all opinions are equally valid, but that even our truest beliefs need the test of opposition to stay alive and earned. Mill feared above all the tyranny of the prevailing opinion, the social pressure that enforces conformity more effectively than any law, and On Liberty is his argument for protecting the dissenter, the eccentric, and the heretic as the people a healthy society cannot do without.

The book is short, public domain, and freely available, and the chapter on freedom of thought and discussion is as relevant now as it has ever been. Read it for the strongest reasons anyone has given for tolerating the people you are sure are wrong.