In an era of rising ethnic nationalism and white supremacy, a British science writer's new book explores why old notions of "race science" are finding new popularity.

This revival drew Angela Saini to explore the history and new life that's been given to the idea that science can justify old ideas of human difference based on skin colour, nationality or religion — what she called the biologization of race. The persistence of this idea in the modern era can be seen in a variety of ways, from the popularity of dubious DNA ancestry testing to shadowy online groups repackaging scientific racism for the 21st century. 

In her new book Superior: The Return of Race Science, Saini traces the history of race science back to the Age of Enlightenment, when philosophers and European thinkers started to classify human beings based on colour or other superficial features, the same way they classified plants or other animals.

Quirks & Quarks host Bob McDonald spoke with Saini about a range of topics: how modern science shows that racial categories are social constructs, not well-defined biological categories; how notions of race science are fed by and feed into politics; and how well-intentioned scientists should think about studying questions about human difference, including marginalized groups who may share susceptibility to disease.

Here is part of their conversation.

You point out that most scientists and philosophers of the time [when racial categories were defined] were white males.

The modern science that we use now, the empirical method, was born in Europe, and many of the people who practised it were upper-class men of wealth, and they had a certain worldview. I think it would be crazy to assume that that worldview wasn't affecting the way that they were thinking about human difference. It's no accident, I don't think, that when they were dividing humans up into categories and deciding that there was a hierarchy between those categories that they always put themselves at the top. 

The race science of that era almost immediately manifested itself in ideology and politics. Can you give me some examples? 

The ideas around racial categories that were devised at the time, in the 18th and 19th centuries, on the one hand … were drawing on the political worldviews that were prevalent at the time in the cultures that they belonged to, and at the same time, the science they were producing.

So when they devised racial categories, that again was used to reinforce the political worldviews that were out there in society. These scientific ideas were used to justify slavery and colonialism, and later genocide and apartheid. So they were always there going hand-in-hand. 

Let's move into the modern era then. Biologists have come up with a really strong scientific critique of the idea of race. Can you take me through that? 

Well, for 70 years since this consensus after the Second World War, all that biology has done is reinforce the fact that we are so similar. We imagine the genetic differences between racial groups.

For example, I am of Indian origin. My parents [were] born in India. But if I were to randomly pick a South Asian person on the street and randomly pick a white, Canadian person on the street and test their genomes, it's perfectly statistically possible for my genome to have more in common with a white person than with the Indian person. That's how almost complete that overlap is. So we are incredibly similar as a species, and the vast majority of difference that we see is accounted for by individual difference. 

If humans as a whole are pretty homogenous genetically, then why does race still feel so real?

It has defined how we are treated by society in the most visceral and fundamental ways because of the politics of it, because of segregation and slavery and all the different ways in which people are treated differently based on the fact that these social categories are thought to exist. We so easily conflate that with biology. We can't help but believe that because these things have such great social meaning that they must have some biological meaning then too, especially because we, in our heads, associate them with biological features. 

There's a kind of an amateur race science that's very popular right now. You can see it with commercial genetic testing. This idea appeals to people of all sorts of backgrounds. Why do you think that is? 

I have to say it has greater appeal in places like the U.S. and Canada, where people tend to be of migrant backgrounds. So, for example, for me, I have never really felt the desire to have my ancestry tested, because I know where my family [is] from. 

But if, say, you are a black American, and because of the history of slavery you were torn apart from that culture and that history and those roots, then DNA ancestry testing does offer what may be the only way you have of reconnecting to what was lost. And it's tragic on so many levels. On one level, because that was done to people that they were ripped apart from their cultures and made to live lives completely removed from them. Secondly, that DNA ancestry testing cannot give you very much. It can't give you that culture back. 

When it comes to studying differences, how do you think the science community can best understand what's reasonable or acceptable to study and what isn't? 

Well, I think, of course, there is human variation, and there are statistical variations that play out in different populations in very subtle ways. I don't think there's any reason not to do that kind of research. In fact, I'm of the view that if you can get your research funded by a reputable organization and published and peer reviewed in a reputable publication, you should be able to whatever kind of research you like. But we have to use these terms carefully.

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Often race is used as a variable without people really defining it biologically, and that is a very minimum we should expect from a scientific variable that you'll be able to define it biologically. They just treat these social categories as though they are biological without really doing the legwork to figure out why that is a valid way to think about these things.

This interview has been edited for length and clarity.