John Stuart Mill’s essay On Liberty (1859) is the most famous work about toleration in the English language. It is clear, concise, logical, and passionate. It defends toleration—of thought, speech, and individuality—as a practical means to promote happiness for the greatest number of people. The book inspired generations of classical liberal thinkers, and today it is probably the only historic work about toleration that most people ever read.
Yet from the standpoint of liberty generally, the philosophy behind On Liberty–Utilitarianism–was a terrible failure. Mill and other Utilitarians relentlessly attacked the doctrine of natural rights, a moral basis for liberty which had provided the only known intellectual barrier to tyranny. Natural rights, as explained by thinkers like Thomas Jefferson and Thomas Paine, defined what governments could not rightfully do. Neither Mill nor any other Utilitarian offered fixed principles to replace natural rights. As far as Mill was concerned, Utilitarianism became a moral plea for socialism. He didn’t anticipate how socialist government power could unleash horrifying intolerance during the twentieth century.
Mill’s opinion had to be reckoned with because he was the most influential English philosopher of the nineteenth century, the author of respected books on economics, logic, and political philosophy, a prolific journalist, the editor of a widely followed journal of opinion, a friend of leading intellectuals in Europe and the United States. People listened when Mill spoke about a vital issue.
Mill owed his influence perhaps as much to his appealing personality as to his intellectual firepower. He was a rational, positive, generous man who sincerely loved liberty. There is moral fervor in On Liberty, even if he couldn’t bring himself to justify liberty for moral reasons. He was far ahead of his time in insisting that women are entitled to equal rights with men–he endured more h...
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