To a woman struggling to be treated equally and taken seriously, Mill’s permissiveness must appear next to useless. All around her, society allows images of women as lumps of meat whose sole purpose is to be enjoyed by men. They thwart her hopes and challenge her sense of who she is and what she may become. But according to Mill, she cannot stop them unless she can prove that pornography and sexualised films and advertising are inciting harm. Why should she accept a bar raised so high she can never jump it? Why should she spend years arguing for men to change, when state power could give her what she wanted in a moment?

The same applies to a black man confronted with the everyday racism of parts of the Right, or a Jew confronted with the everyday racism of Islamists and parts of the Left, or a gay man worried about homophobia or a Muslim frightened of Islamophobia. They don’t want to be told they can ban speech only if a speaker urges his audience to attack a mosque or a gay bar or a synagogue. They feel the hurt of prejudice right now, and have no time to argue.

I will go further and say that, regardless of colour or creed, most people who have suffered from insults have wanted their abuser silenced, even if what he said was true—especially if what he said was true.

The American legal philosopher Joel Feinberg attacked Mill by saying that we feel offence like a wound. You only have to think about the hurt from slights that have stayed with you longer than the pain from a broken bone to see the truth in his argument. Societies and individuals feel disgust, revulsion, shock, shame and embarrassment when they hear views that don’t physically harm them, Feinberg said in the 1980s. They can and should replace Mill’s “harm principle” with his “offence principle”—that the law can stop speech that causes serious offence.

Feinberg’s mild authoritarianism buttressed the illiberal version of liberalism that flourishes to this day. It supports the laws against “hate speech” which may not be so hateful it provokes its audience to violence, but is still grossly offensive. It provides the philosophical justification for the incessant Twitter storms and media fits about “gaffes”, “misspeaks”, or to use a modern phrase that reeks of the Victorian drawing-room, “inappropriate language”.

Go into the modern university and you won’t hear much about Mill or Milton or the millions around the world who have had to learn the hard way why freedom of speech matters. Instead, you will be fed philosophers far less rigorous than Feinberg. The New Zealander Jeremy Waldron, an Oxford professor from the American university system, which churns out authoritarian philosophers the way Ford churns out cars, suggests speech that attacks the dignity of others should be banned. Stanley Fish of New York dispenses with any pretence that we should respect universal human rights, and descends into power-worship and thuggery. “The only way to fight hate speech is to recognise it as the speech of your enemy,” he says. “And what you do in response to the speech of your enemy is not prescribe a medication for it but attempt to stamp it out.” Take a breath and think about his assumptions. This is the tyrannical language of an illiberal intelligentsia so lost in complacency it thinks it no longer needs the rights it once championed.We don’t care if we are being consistent, it says. We have the power to censor now and we will use it.

Few contemporary theorists grasp that people oppose censorship not because they respect the words of the speaker but because they fear the power of the censor. It is astonishing that professed liberals, of all people, could have torn up the old limits, when they couldn’t answer the obvious next question: who decides what is offensive?