For a vivid parable of what is wrong with contemporary discourse and culture – and of what could be right – look no further than last week’s Channel 4 News interview of Jordan Peterson, by Cathy Newman. At the time of writing, her half-hour grilling of the Toronto University professor of psychology has clocked up more than 2.3m views on YouTube, and provoked a cacophonous response across social media. So shamefully abusive have many of the attacks on Newman been that Channel 4 announced on Friday that it had called in security specialists.

As the digital temperature rose, Peterson quite rightly intervened on Twitter to stop the abuse: “If you’re threatening her, stop. Try to be civilized in your criticism.” It is unconscionable that a journalist doing her job should be threatened as Newman has been by “alt-right” idiots, with their pathetic Pepe the frog symbol, juvenile memes and claims that their adversaries have been “rekt”.

The onslaught has also eclipsed the content of a genuinely illuminating exchange. Newman is one of the best broadcasters in the business. Peterson is one of the most eclectic and stimulating public intellectuals at large today, fearless and impassioned in his philosophical inquiries, his application of clinical psychology to sensitive social dilemmas, and his critique of postmodernism and neo-Marxism in academia. His opinions are not to everyone’s taste, and his new book, 12 Rules for Life: An Antidote to Chaos – which I greatly enjoyed – has infuriated others. But so what?

Though it is unfair to pigeonhole two such intelligent people, the conversation between Peterson and Newman, distilled to its essentials, was an argument between classical liberal ideas and modern identity politics. Peterson made his case with reference to individual characteristics and attributes; Newman challenged him to consider the structural disadvantages facing, say, women in the workplace or transgender students.

Are we really going down the road where speech is included in the same category as fists and batons?

Do watch the whole thing. It is absolutely not the one-sided rout of Newman that the far right alleges. On equal pay, I thought she had the psychologist on the ropes more than once. On the right to offend, Peterson was on stronger ground. “In order to be able to think, you have to risk being offensive,” he said. “I mean, look at the conversation we’re having right now. You’re certainly willing to risk offending me in the pursuit of truth … And that is what you should do … More power to you, as far as I concerned.”

It is much to Newman’s credit that, 23 minutes in, she drew breath, paused and considered her position. We say that we want our interviewers to be less pugnacious and more thoughtful – and yet we pillory them when they have the guts to be contemplative on air. There are plenty of people who think that Peterson has no place on a mainstream news programme, or even in academic life. The far right, on the other hand, believes that Newman personifies an elitist media caste that is obstructing a great populist revolution. Both groups are ridiculous, and spectacularly ignorant of what constitutes a progressive civilisation. They reduce human interaction to tedious name-calling between the “woke” and the “red-pilled”, awake to the truth of reality.

It cannot be said too often that the first amendment to the United States constitution was adopted with the explicit purpose of protecting minority opinion. Though we have no such jurisprudential protection in Britain, and we – like most democratic societies – curtail speech that is libellous, incites imminent violence or whips up racial hatred, our inherited presumption in favour of free expression is more important than ever. A pluralistic, diverse society needs more free speech, not less. It needs fewer safe spaces and bans, and more civility and resilience.

Now, I know what some of you are thinking: what right does a white, middle-class, straight, cis male who turns 50 this week have to say anything about this? And the answer is: I say what I like, within the law, and so do you.

Object that “speech is violence”, and I reply: tell that to the 262 reporters who, according to the Committee to Protect Journalists, were imprisoned last year – a record high. It has become fashionable to claim that the wrong kind of words can cause damage to our “neural circuitry”. To which I say – really? Are we really going down the road where speech is included in the same category as fists and batons? Because once you allow that philosophical elision, you essentially ditch the Enlightenment – which, speaking for myself, I still find quite handy to have about the place.

Of all the delusions that grip our fractious era, one of the worst is the confident belief that greater restriction of speech will necessarily serve progressive ends. I see no logic in that whatsoever. As Peterson warns, everyone finds something objectionable or upsetting. It would be a moment of maximum peril if the primary test applied to expression became its capacity to offend. Why assume that those setting the rules would necessarily support the powerless or the disenfranchised? The injunction “You can’t say that” leads just as plausibly to Margaret Atwood’s Gilead or to Oceania.

To be a citizen is to engage, and the Newman-Peterson interview is a model of that engagement. Unless you believe that history has a self-evident direction – and it really doesn’t – you must accept that almost all progress is achieved by the hard grind of negotiation, tough debate and busy pluralism. The aphasia of “no-platform” and the bedlam of the digital mob add nothing to the mix. To quote the great African-American scholar Henry Louis Gates: let them talk.

• Matthew d’Ancona is a Guardian columnist