Nick Cohen responds to the ill-mannered Nassim Nicholas Taleb.

The spat would not be worth mentioning if it did not show how nothing is now free from the culture war. That nothing includes the skin colours of the population of Roman Britain.

You may need to bear with me as I explain. In December, BBC Teach released on YouTube a video about life in Roman Britain. Shockingly, as it was to turn out, it featured a Roman with dark skin. An editor working for Infowars went on the attack. ‘Thank God the BBC is portraying Roman Britain as ethnically diverse. I mean, who cares about historical accuracy, right?’ Infowars, in case you haven’t heard of it either, is run by Alex Jones. You can call him a cynic or you can call him a madman, according to taste, but he has built his income by spawning the most grotesque conspiracy theories. Like Taleb, he wouldn’t be worth bothering with, were it not a matter of record that Donald Trump is a fan. The fringe has become the mainstream, as I keep saying. Those who don’t fight the cranks before they become powerful are doomed to be governed by them when they do.

True, and sadly so are the rest of us even though we did fight the cranks before they became powerful. God damn it it is so unfair.

Mary Beard said on Twitter that the BBC’s history lesson was ‘indeed pretty accurate, there’s plenty of firm evidence for ethnic diversity in Roman Britain’. Taleb jumped in, and half the creeps on cyberspace followed him. Genetic evidence did not show blacks were in Roman Britain, he said, or I should say appeared to say – his argument was hard to follow, ‘Genes better statisticians than historian hearsay bullshit,’ Taleb continued.

I must try to be fair. Taleb may appear to be a strutting, preening, loudmouthed lout. He may boast like a secretly insecure phoney and rage like a punch-drunk lightweight.

But that doesn’t make him wrong on the facts; that has to be considered separately. Is he wrong on the facts?

So let us see how the evidence stacks up. It is indeed true that the ‘People of the British Isles’ study found no evidence of the 400-year Roman occupation in the genetic makeup of the British. But then it found no genetic evidence that the Danes invaded. That doesn’t mean the Romans and the Danes weren’t here.

Adam Rutherford has just published A Brief History of Everyone Who Ever Lived, a wonderful book which takes the reader through the exploding science of what genes tell us about human history. After he had told me that some of the assertions Taleb was coming out with made no sense at all, Rutherford explained that DNA from Roman remains is hard to find and harder still to examine. ‘It is certainly possible to reconstruct certain aspects of historical demography from DNA extracted from bones, but the picture will never be complete. Some people assert facts based on DNA evidence trumps all we believe’ – he may have been thinking of Taleb here – but ‘DNA is merely another strand of historical evidence, which only works in concert with the more traditional forms of knowing the past.’

I’m going to make a wild guess here that one reason the picture will never be complete is because we’ll never have all the DNA there is to have. In many circumstances not finding X does not mean X doesn’t exist. That in fact is the point of “the black swan” trope, which Taleb seized from philosophy. It reminds us that what we can currently detect is not necessarily all there is to detect.

And those other strands show that the multinational Roman Empire brought its multinational citizens to Britain. Beard said she thought that the BBC character was loosely based on Quintus Lollius Urbicus, a man from what is now Algeria, who became governor of Britain. For classical historians, the notion that Roman Britain included people from across the empire is ‘pretty well taken for granted, as a starting point for more detailed and interesting investigations,’ as Neville Morley of Exeter University says.

Rome was an empire. It would be odd if there were no mixing of peoples in an empire.

The last thing this debate is about is history, however. The Trump presidency and the rise of nationalist movements across Europe is politicising the past. If you are Trumpian blowhard, you see an innocuous BBC cartoon showing a black Roman in Britain as an affront. Even if you do not feel affronted, you know you can whip up your supporters to feel offended. For if you do not keep them in a state of perpetual outrage, the wheels would fall off your bandwagon, and then where would you be?

A black face in these circumstances is a provocation and a lie: “bullshit” to use another of the great public intellectual’s favourite words. Indeed, it is worse than a lie: it is propaganda from the globalist multicultural elite, designed to brainwash the masses into believing diversity is a part of our history.

The effort is sinister for two reasons. I am not the type of liberal who throws accusations of racism around. But come now. The torrent of fury Taleb unleashed on Beard has one cause and one cause only: her statement that Roman Britain was diverse. If she had intervened on a controversy about slavery and the agrarian Roman economy, no one would have cared.

I’m going to suggest it has another cause in addition to that one. Beard is a woman. Men like Taleb cannot resist the urge to vomit their bile all over women who dare to say they got something wrong. There are a great many men like Taleb trampling all over the public discourse right now.

Second, and in my view just as sinister, is what the alt-right and politically correct left are doing to public life.

My point exactly. Part of what they are doing to public life is making it just normal for women to expect torrents of abuse simply for participating.