Very interesting stuff. I'm not totally convinced though. While I agree that dividing people by race is wrong, there are physical differences between people from different places. Isolating (at least the majority of) one population from another for thousands of years will inevitably cause differences to emerge, and we may not know the extent of them. We can see examples in nature of other species diverging after being isolated, and we know that it happened in humans at least with skin color and bone structure. Why could the same not happen with, for example, psychological traits? I should clarify that I'm not attempting to justify any form of racial discrimination. We're all still human and there's no good reason to discriminate based on race. Even if we had a logical reason for racism, it would be impossible to know where to draw the line between one race and another if you take into account mixed-race people and minor differences in characteristics of people from the same general geographic area (such as between north and sub-Saharan Africa, Nordic countries and Southern Europe, etc.)