"...What is race? In particular, adherence to different political and moral philosophies, as we shall see, permits rather different answers. But I believe it is useful at the outset to bracket the cultural factors and explore some of the implications of a strictly biological approach.
The evolutionary literature explains why there are geographic races. Every local population of a species has its own gene pool with its own mutations and errors of sampling. And every population is subject to selection by the local environment. There is now a large literature on the environmental factors that may influence the geographic variation of a species. For example, populations of warm-blooded vertebrates (mammals and birds) in the colder part of their geographical range tend to larger size (Bergmann's rule). Darwin wondered whether these climatic factors were sufficient to account for the differences between geographic races in the human species. He finally concluded that sexual selection, the preference of women for certain types of men, might be another factor leading to differences between geographic races.
This kind of biological analysis is necessary but not sufficient. By itself, biology cannot explain the vehemence of the modern controversy over race. Historically, the word "race" has had very different meanings for different people holding different political philosophies. Furthermore, in the last two hundred years there has been a change in the dominant philosophy of race.
In the eighteenth century, when America's Constitution was written, all our concepts were dominated by the thinking of the physical sciences. Classes of entities were conceived in terms of Platonic essentialism. Each class (eidos) corresponded to a definite type that was constant and invariant. Variation never entered into discussions because it was considered to be "accidental" and hence irrelevant. A different race was considered a different type. A white European was a different type from a black African. This went so far that certain authors considered the human races to be different species.
It was the great, and far too little appreciated, achievement of Charles Darwin to have replaced this typological approach by what we now call population thinking. In this new thinking, the biological uniqueness of every individual is recognized, and the inhabitants of a certain geographic region are considered a biopopulation. In such a biopopulation, no two individuals are the same, and this is true even for the six billion humans now on Earth. And, most important, each biopopulation is highly variable, and its individuals greatly differ from each other, thanks to the unique genetic combinations that result from this variability.
Let me illustrate the implications of individual differences by analyzing the outcome of the 2001 Boston marathon. Kenyans are a population famous for producing long-distance runners. Three Kenyans had entered the race, and it was predicted that they would end the race as numbers one, two, and three. However, to everybody's great surprise, the winner was a Korean, and, even more surprisingly, number two was an Ecuadorian from a population that had never been credited with long-distance running abilities. It was a clear refutation of a typological - or essentialist - approach to thinking about race.
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When dealing with human races we must think of them as the inhabitants of the geographic region in which they had originated. Presumably each human race consists of individuals who, on average and in certain ways, are demonstrably superior to the average individual of another race. Eskimos, for instance, are superior in their adaptedness to cold. In the last four or five Olympics there were always six to eight contenders of African descent among the ten finalists in the sprinting races, surely not an accidental percentage.
These considerations should teach us how we should think about human races. A human race consists of the descendants of a once-isolated geographical population primarily adapted for the environmental conditions of their original home country. But, as is illustrated by the success of Europeans and Africans and Asians in all parts of the world, any race is capable of living anywhere. Most importantly, a race is always highly variable: any human race will include a wide variety of extraordinary individuals who excel in very different human abilities."
