Accidental encounters with racists lead me to believe that they are open to neither reason nor self-improvement. I must conclude, then, that a book entitled How to Argue With a Racist will remain untouched by those who would most benefit from reading it. This is a pity, as there is a growing army who have succumbed to a phenomenon known as “race realism”. This is racism reinterpreted for the internet age: a heady brew of misunderstood science, ugly conspiracy and plain old prejudice that forms the basis of (usually) far-right and white supremacist thinking.

Race realism promotes the spurious idea that science has uncovered distinct and meaningful differences between races but that this “truth” is somehow suppressed by snowflake scientists in hock to political correctness. Those supposed truths are then contorted by their abusers into parodies of racial destiny: black men are born to sprint but not to swim; Jews are born into moneylending; and, of course, whites are born above all others. Black people are several rungs below white peers on the social ladder not because of systemic oppression and discrimination but because they are naturally more stupid.

It is a perverse system of thought that seeks to justify racial separateness and conveniently reinforce assertions of white superiority. This is an ideology treading water amid the flood of data pouring out of genetics studies and a mistaken concept of ancestry propagated by the consumer DNA testing market – which happily nurtures fantasies of Viking descent.

The claim that genetics supports any form of racism – or that it supports the idea of race as a biologically meaningful concept – is a fallacy, argues the geneticist, author and Twitter warrior Adam Rutherford, in this slim, two-fingered salute to the haters: “The continual failure to settle on the number of races is indicative of its folly. No one has ever agreed how many races there are, nor what their essential features might be, aside from the sweeping generalisations about skin colour, hair texture and some facial features.” The clear genetic boundaries that racists crave to bolster their narrative are simply absent from the analyses of our 20,000-odd genes and their variants.

Rutherford, a British science writer whose previous books include Creation and The Book of Humans, divides his analysis into chapters covering skin colour, ancestral purity, sporting prowess and intelligence. Just as you cannot tell the function of a room by the colour of its walls, skin colour is a rotten guide to the biological realities hidden within. “The dominance of skin colour as a racial classifier is based on historical pseudoscience primarily invented during the years of European empire-building and colonial expansion,” he summarises, having pointed out that the “vast tapestry” of pigmentation found in Africa’s 54 countries overlaps with Indians, aboriginal Australians, South Americans and some Europeans.

When it comes ancestry, there is no such thing as purity. The mathematics of family trees, when traced back far enough, reveals convergence. There are “isopoints”, or nodes of origin, that propagated all the many branches we see today. For instance, everyone now alive is an ancestor of the global population 3,400 years ago, in which the blood of many different peoples had already mixed.

While some populations might have taken root in a particular geographical location over a few generations, the joy of sex meant our frisky forebears got it wherever they could. And so, Rutherford explains, every Nazi has Jewish ancestors and “every racist has African, Indian, Chinese, Native American, aboriginal Australian ancestors… there are no purebloods, only mongrels enriched by the blood of multitudes”.

The idea of innate athleticism is complicated: it is true that Olympic sprinters tend to be of West African heritage, even if they come from the US, Canada or the Caribbean. But we can infer too much from too little, Rutherford maintains: all Olympians are outliers, and a statistically thin set from which to draw sweeping conclusions. If West African genes are the key to medal glory, why don’t sprinters representing that region similarly excel? While one version of a gene called ACTN3 (sometimes called the “speed gene”) is common in sprinters and in people of West African descent, it is also found in other groups, and so by itself cannot explain outstanding performance. Why, he asks, do we not see many black swimmers, where “athletic” genes might also confer an advantage?

Rutherford concludes, quite reasonably, that it is environment, culture and role models that make the difference in sport; the dominance of East Africans in long-distance running can be ascribed to a running culture that has sprung up in Ethiopia and Kenya, both home to superstar endurance runners and intensive training camps for hopeful youngsters.

***

The most explosive issue in genetics and race is, of course, intelligence. It is almost impossible to do justice to his nuanced arguments in a paragraph, but here is a snapshot: while the UK shows a population average IQ of 100, meta-analyses suggest that countries in Africa are likely to score in the 80s. Genetic factors cannot be fully excluded, Rutherford says, but the enormous genetic diversity across that vast region suggests the discrepancy lies in the challenging local environment, with poorer schools and fragile medical care, rather than in the genes.

In fact, today’s sub-Saharan countries are comparable, in socio-economic terms, to European countries in the first half of the 20th century. National IQs have a habit of gradually increasing, and the so-called Flynn effect might see the IQs in those countries lift over time. Even at the national level, he might have usefully added,

poverty and disadvantage affects educational outcome.

Rutherford casts doubt on the assertion that Jews are intellectually gifted because of their genes, again invoking the Ockham’s razor of culture to explain why Jewish people keep winning Nobel Prizes: “The evidence for selection of genes for intellect in Jews is weak. Is it not simply more scientifically parsimonious to suggest that a culture that values scholarship is more likely to produce scholars?” I begrudged, though, his continual digressions about whether scientists who held racist views – such as the co-discoverer of DNA James Watson – deserve to have their science trashed. It is entirely appropriate to interrogate a scientist’s motives for choosing a particular line of inquiry.

It is hard not to compare Rutherford’s effort to Superior, the excellent book by Angela Saini on race science published last year. Rutherford makes no reference to it, although, by necessity, he references some of the same research.

He is undoubtedly a gifted communicator, and his is the quicker, bolshier read, but Saini is a hard act to follow in laying out the misuse of science for racist ends. Not only did Saini courageously challenge some of the culprits, but she also set her critique in detailed historical context, explaining how race became embedded in the scientific culture of classification in the 18th and 19th centuries. That was the origin of eugenics: the idea that the genetics of the human race can be improved via selective breeding. Its shadow still hangs over us today, thanks to a small gaggle of fringe researchers who continue to drip-feed nationalist forums with a selective stream of misinterpreted data from population studies (biologists no longer study race, remember, but “populations”, because of the lack of clear genetic boundaries between people).

That said, writers such as Saini and Rutherford are needed more than ever in our confusing, polarised times. Charles Murray, the right-wing thinker who co-wrote The Bell Curve – which, among other things, pointed to IQ differences between white and black people and discussed how this could affect social policy – has a new book out that invokes genetics to challenge “woke” thinking on gender, race and class. Such prophets thrive in pop culture, exploiting the inevitable gaps and uncertainties in scientific data to fan the flames of division, and using the shield of free speech to brush off accusations of poor or selective scholarship.

My interpretation is that those who covertly, or overtly, push the anti-woke agenda fear that their own status is threatened by positive social change. Society becomes a zero-sum game in which the rise of minorities must mean the fall of the majority. This fear is embodied in the fixation on the demise of Western culture, which animates so much hostility towards minorities.

“[White supremacists] fantasise about a persecution of their people that will end in their extinction, or an erosion of their rights in exchange for the same rights afforded to people of different heritage,” Rutherford observes. “When all you’ve ever known is privilege, equality feels like oppression.”

That is how I would argue with a racist who takes offence at modernity and social progress: the real problem is not that my skin is too dark but that yours is too thin.

Anjana Ahuja is a contributing writer on science for the Financial Times

How To Argue With a Racist: History, Science, Race and Reality

Adam Rutherford

Weidenfeld & Nicolson, 224pp, £12.99