In 1871 biologist Charles Darwin published The Descent of Man, sweeping away these religious creation myths and framing the human species as having had one common ancestor many millennia ago, evolving slowly like all other life on earth. Studying humans across the world, their emotions and expressions, he wrote, “It seems improbable to me in the highest degree that so much similarity, or rather identity of structure, could have been acquired by independent means.”

We are too alike in our basic responses, our smiles and tears, our blushes. On this alone, Darwin might have settled the race debate. He demonstrated that we could only have evolved from shared origins, that human races didn’t emerge separately.

On a personal level, this was important to him. Darwin’s family included influential abolitionists, his grandfathers Erasmus Darwin and Josiah Wedgwood. He himself had seen the brutality of slavery first-hand on his travels. When naturalist Louis Agassiz in the United States spoke about human races having separate origins, Darwin wrote disparagingly in a letter that this must have come as comfort to slaveholding Southerners.

But this wasn’t the last word on the subject. Darwin still struggled when it came to race.

Like Abraham Lincoln, who was born on the same day, he opposed slavery but was also ambivalent on the question of whether black Africans and Australians were strictly equal to white Europeans on the evolutionary scale. He left open the possibility that, even though we could all be traced back to a common ancestor, that we were the same kind, populations may have diverged since then, producing levels of difference.

As British anthropologist Tim Ingold notes, Darwin saw gradations between the “highest men of the highest races and the lowest savages”. He suggested, for example, that the “children of savages” have a stronger tendency to protrude their lips when they sulk than European children, because they are closer to the “primordial condition”, similar to chimps. Gregory Radick, historian and philosopher of science at the University of Leeds, observes that Darwin, even though he made such a bold and original contribution to the idea of racial unity, also seemed to be unembarrassed by his belief in an evolutionary hierarchy. Men were above women, and white races were above others.

In combination with the politics of the day, this was devastating. Uncertainty around the biological facts left more than enough room for ideology to be mixed with real science, fabricating fresh racial myths. Some argued that brown and yellow races were a bit higher up than black, while whites were the most evolved, and by implication, the most civilised and the most human.

What was seen to be the success of the white races became couched in the language of the “survival of the fittest”, with the implication that the most “primitive” peoples, as they were described, would inevitably lose the struggle for survival as the human race evolved.

Rather than seeing evolution acting to make a species better adapted to its particular environment, Tim Ingold argues that Darwin himself began to frame evolution as an “imperialist doctrine of progress”.

“In bringing the rise of science and civilisation within the compass of the same evolutionary process that had made humans out of apes, and apes out of creatures lower in the scale, Darwin was forced to attribute what he saw as the ascendancy of reason to hereditary endowment,” writes Ingold. “For the theory to work, there had to be significant differences in such endowment between ‘tribes’ or ‘nations’.” For hunter-gatherers to live so differently from city-dwellers, the logic goes, it must be that their brains had not yet progressed to the same stage of evolution.

Adding fuel to this bonfire of flawed thinking (after all, we know that the brains of hunter-gatherers are no different from those of anyone else) were Darwin’s supporters, some of whom happened to be fervent racists. The English biologist Thomas Henry Huxley, known as “Darwin’s Bulldog”, argued that not all humans were equal. In an 1865 essay on the emancipation of black slaves, he wrote that the average white was “bigger brained”, adding, “The highest places in the hierarchy of civilisation will assuredly not be within the reach of our dusky cousins.”

For Huxley, freeing slaves was a morally good thing for white men to do, but the raw facts of biology made the idea of equal rights – for women as well as for black people – little more than an “illogical delusion”.

In Germany, meanwhile, Darwin’s loudest cheerleader was Ernst Haeckel, who taught zoology at the University of Jena from 1862, and was a proud nationalist. He liked to draw connections between black Africans and primates, seeing them as a kind of living “missing link” in the evolutionary chain that connected apes to white Europeans.

Darwinism did nothing to inhibit racism. Instead, ideas about the existence of different races and their relative superiority were merely repackaged in new theories. Science, or the lack of it, managed only to legitimise racism, rather than quash it. Whatever real and reasonable questions might have been asked about human difference were always tainted by power and money.

Superior The Return of Race Science

Excerpted with permission from Superior: The Return of Race Science, Angela Saini, HarperCollins India.