Why do we still believe in race? There are two common answers, depending on which side of the fence you stand on the meaning of race. Those who believe that race is a biological reality argue that we still believe in it - well, because it's a biological reality. Those who view race, not as a biological entity but as a social construction, argue that science has disproved the reality of race, and only prejudice gives it validity.
Ironically, the more we find out about human biology, the less certain scientists appear to be about the meaning of race. For Craig Venter, one of the key figures behind the unravelling of the human genome, 'The Human Genome Project shows there is no such thing as race'. The equally distinguished geneticist Neil Risch insists that 'A decade or more of population genetics have documented biological differences between the races.'
Why such disagreement? Science provides us with data about differences between human populations. But the question of how we interpret that data is beyond its domain. To put it another way, science can neither confirm nor disconfirm race as a biological reality, because race is a not scientific category.
To see this more clearly, let us look at both the traditional liberal arguments against the biological idea of race and at the arguments of the so-called race realists. Both sets of arguments, I want to suggest, are found wanting.
Three main arguments are used to justify the belief that race is meaningless as a biological category. First, most human genetic variation exists within populations; 'racial' differences are tiny. Second, all human populations merge into each other, making it difficult to divide humans into distinct races. And third, Homo sapiens is too young a species for racial differentiation to have biological meaning. Let us look at these arguments in turn.
All humans are genetically virtually identical. And virtually all the variation that does exist, lies within populations, not between races. Imagine that some nuclear nightmare wiped out the entire human race apart from one small population - say, the Masai tribe in East Africa. Most of the genetic variation that exists in the world today would still be present in that one small group. That is a dramatic way of expressing the results of a landmark analysis conducted by the geneticist Richard Lewontin in 1972. Lewontin showed that virtually all human variety - 85 per cent - occurred between individuals within single populations. A further 7 per cent differentiated populations within what we call a race. Only 8 per cent of total variation distinguished the major races.
The results from a recent study by geneticist Noah Rosenberg are even more striking. They show that differences among individuals account for a staggering 93-95 percent of all genetic variation, while racial differences account for just 3-5 per cent.
At first sight such studies seem to demolish the biological idea of race. Racial differences appear too small to be meaningful. Tiny genetic differences can, however, have a huge impact. From a genetic point of view poodles and greyhounds are almost identical, yet they are physically and behaviourally distinct. Humans and chimpanzees share about 99.4 per cent of their functional genes but are clearly different species. So the fact that race accounts for only around four per cent of genetic variation among humans does not necessarily mean that race has no biological validity. That four per cent could, theoretically, make all the difference in the world.
The people of China look different from those of Kenya. But there is no point between Nairobi and Beijing at which the race to which Kenyans belong ends and those to which Chinese belong begins. Every population shades imperceptibly into another. Since there are no clearcut divisions between populations, many suggest, so race cannot exist in any meaningful sense.
Even race realists acknowledge the problem. The journalist Jon Entine, a strong advocate of the race concept, observes that dividing humans into races 'is akin to wrestling an octopus into a shoe box: no matter how hard you fight with it, you still have something dangling out somewhere. Modern typologists cannot even agree whether it is more meaningful to lump races into large fuzzy groups or split them into smaller units of dozens or even hundreds of populations.'
When even a strong proponent of the race concept has doubts perhaps it is time to give up on the idea. But countless real categories have fuzzy boundaries. Among many non-human animals, for instance, subspecies are often separated by a continuous gradation rather than by a sharp boundary. The fuzziness of boundaries does not necessarily deny the existence of races.
Recent genetic research suggests that it may indeed possible to divide up humanity into racial groups. The same study by Noah Rosenberg that showed that racial differences account for as little as four per cent of total human variation, also showed that it is nevertheless feasible to distinguish between races.
Rosenberg studied 377 DNA sequences from 1056 individuals across 52 populations worldwide utilising a software programme called Structure, which finds the most rational way of disaggregating any set of data into distinct categories. When asked to break the data up into five groups, Structure created clusters that correlated closely with what we call 'races': sub-Saharan Africans, Caucasians, East Asians, Australasians and Native Americans. Rosenberg's study seems to suggest that, however small the differences between races, they are nevertheless sufficient to pick them out.
Modern humans first evolved on the East African savannah some 150,000 years ago, but did not begin migrating to the rest of the world for another 90,000 years. Any differences between races, therefore, would be at most 60,000 years old. For many, there simply has not been sufficient time to develop deep divisions between races.
We know, though, of many genetic mutations that have spread rapidly. The gene for lactose tolerance, for example, which allows human adults to digest milk, came to dominate in agricultural communities in the space of a few thousand years. Today, lactose tolerance is widespread among people who come from areas that have a long history of agriculture, including Europe, the Middle East and South Asia. But people from other areas - such as East Asia - remain lactose intolerant, and find it difficult to digest milk.
In any case, genetic differences between races are likely to have been the result, not primarily of natural selection, but of two other evolutionary forces, whose effects show up much more quickly - genetic drift and the founder effect. Genetic drift refers to the random changes to gene frequencies that occurs over time, especially in a small population. The most extreme case of genetic drift is called the 'founder effect'. If a small number of people leave one community to form another one, the two groups are, thanks to chance differences, unlikely to have exactly the same genetic profiles.
Each band of people that moved out of Africa to populate the rest of the world would have had a distinct genetic profile. Along the way, new genetic mutations would have been picked up. And as a result of genetic drift, the genetic profiles of the different populations would have continued to move apart. All this, race realists argue, would be sufficient to explain major differences between the races.
So, does science really tell us that race is a biological fact? It does not. For while science does not absolutely close the door on the idea of race, it certainly does not open it either.
The debate about race is not a debate about whether differences exist between human populations - they do - but about the significance of such differences. In the nineteenth century races were seen as fixed groups, almost akin to distinct species, each with special behaviour and physical characteristics that distinguished one from the other. The races could be ranked on an evolutionary hierarchy, with whites at the top and blacks at the bottom.
Today, with a few exceptions, race realists reject the idea that there are essential differences between human populations, or that differences signify inferiority or superiority. But that has made race a highly flaky concept. No one knows quite how to define it. We can see this if we look at the three major claims as to what constitutes a race.
A race, the biologist Alice Brues writes, is 'a division of a species which differs from other divisions by the frequency with which certain hereditary traits appear among its members'. Races, in other words, are distinguished from each other not because they possess unique, fixed genetic features, but because one differs from another statistically in the frequencies of particular genes. Europeans are more likely to have blue eyes, Africans less likely to suffer from cystic fibrosis.
The trouble is, if we were to test for enough genes, we could find a statistical difference between almost any two populations. 'If we look at enough genes', the geneticist Luigi Luca Cavalli-Sforza observes, 'the genetic distance between Pisa and Florence in Italy is most likely to be significant'.
If any population in the world can be defined as a distinct 'race', then the concept becomes meaningless. As Cavalli-Sfroza puts it, 'classifying the world's population into several hundreds of thousands or a million different races' is 'impractical'. The anthropologist Vincent Sarich responds that 'it is for Nature to tell us' what is a 'reasonable' number of races. But if the people of Pisa and Florence are seen as distinct races, then Nature is probably telling us to trash this particular definition of race.
One attempt to overcome the problem of any population being potentially a race is to link race to one's continent of origin. The world's inhabited continents - Africa, Europe, Asia, Australia and the Americas - correspond roughly to the five major races. And that's not surprising, say the race realists. Once the first bands of humans coming out of Africa each with a slightly different genetic signature, settled in their new homelands, geographical barriers ensured greater population movements within continents than between them. Hence genetic differences between continental populations were maintained and even sharpened.
Neil Risch suggests that linking races and continents works because 'genetic differentiation is greatest when defined on a continental basis'. In fact, the greatest genetic differentiation is not between Continental groups but between Africans and non-Africans. Caucasians, East Asians, Australians and Native Americans are significantly closer to each other genetically than any of these groups are to sub-Saharan Africans. If we defined races simply according to the greatest degree of genetic difference, we would conclude that there are just two races - Africans and non-Africans.
At the same time there is considerable genetic differentiation within Continental groups. And in many, perhaps most, contexts, investigating these finer-grained differences is far more useful than dividing up the world into broad Continental groups.
Take, for instance, the study of sickle cell anaemia. We all know it is a black disease. Except that it isn't. Sickle cell is a disease of populations originating from areas with high incidence of malaria. West Africa is one of those areas. African Americans, descended from West African slaves suffer disproportionately from the trait. But South Africans do not. In fact the majority of Africans don't suffer from sickle cell, but many non-Africans - including southern Europeans and Indians - do. But given popular ideas about race, most people automatically assume that what applies to black Americans applies to all blacks and only to blacks. In this and other cases thinking of race in Continental terms obscures rather than clarifies the importance of genetic differences.
Continental groups represent neither the greatest degree of genetic differentiation within humankind, nor necessarily the most useful way of dividing up human populations. There is no rational reason to define race by continent.
As a result of these problems in defining a race, some race realists have bitten the bullet and accepted that race is effectively genealogy. 'Roughly defined', the philosopher Max Hocutt argues 'a member of race R is an individual whose forebears were members of race R'. Just as 'an animal is a coyote if it is descended from a coyote', so 'a human being is an Afro-American if she is descended from Americans whose forebears were Africans'. Or as Steve Sailer, founder of the self-styled Human Biodiversity Institute, puts it 'a race is an extended family that is inbred to some degree'. There is, he claims, 'no need to say just how big the extended family has to be or just how inbred'. Africans, Icelanders, Basques, even Northern Irish Protestants and Northern Ireland Catholics all constitute distinct races.
Of course, how one defines an 'African' or a 'Basque' is slightly more complicated than how one defines a 'coyote'. Human populations and identities are not natural phenomena but shaped by complex social and historical developments.
In any case, even if human populations were as easy to define as animal species, we are still faced with the old problem: if any group can be a race, then the concept of race becomes meaningless. The problem for race realists today is the very opposite of that for nineteenth century racial scientists. Then, racial scientists 'knew' the significance of race but could find no way of truly defining differences. Today, we can define genetic differences between populations with some precision. But the significance of such differences no longer seems clear.
But, then, the question remains: if race is such a flaky concept, why do we continue to believe in it? And why is it returning as a category in both scientific research and medical practice? Those are questions that I will explore in part two of this essay.