Science often violates simple common sense. Our eyes tell us that the Earth is flat, that the sun revolves around the Earth, and that we humans are not animals. But we now ignore that evidence of our senses. We have learned that our planet is in fact round and revolves around the sun, and that humans are slightly modified chimpanzees. The reality of human races is another commonsense "truth" destined to follow the flat Earth into oblivion.
The commonsense view of races goes somewhat as follows. All native Swedes differ from all native Nigerians in appearance: there is no Swede whom you would mistake for a Nigerian, and vice versa. Swedes have lighter skin than Nigerians do. They also generally have blond or light brown hair, while Nigerians have very dark hair. Nigerians usually have more tightly coiled hair than Swedes do, dark eyes as opposed to eyes that are blue or gray, and fuller lips and broader noses.
In addition, other Europeans look much more like Swedes than like Nigerians, while other peoples of sub-Saharan Africa--except perhaps the Khoisan peoples of southern Africa--look much more like Nigerians than like Swedes. Yes, skin color does get darker in Europe toward the Mediterranean, but it is still lighter than the skin of sub-Saharan Africans. In Europe, very dark or curly hair becomes more common outside Scandinavia, but European hair is still not as tightly coiled as in Africa. Since it's easy then to distinguish almost any native European from any native sub-Saharan African, we recognize Europeans and sub-Saharan Africans as distinct races, which we name for their skin colors: whites and blacks, respectively.
What could be more objective?
As it turns out, this seemingly unassailable reasoning is not objective. There are many different, equally valid procedures for defining races, and those different procedures yield very different classifications. One such procedure would group Italians and Greeks with most African blacks. It would classify Xhosas--the South African "black" group to which President Nelson Mandela belongs--with Swedes rather than Nigerians. Another equally valid procedure would place Swedes with Fulani (a Nigerian "black" group) and not with Italians, who would again be grouped with most other African blacks. Still another procedure would keep Swedes and Italians separate from all African blacks but would throw the Swedes and Italians into the same race as New Guineans and American Indians. Faced with such differing classifications, many anthropologists today conclude that one cannot recognize any human races at all.
