1. Race as a biological-genetic reality?

Before one can examine whether there are race group differences in intelligence (IQ, 'g'), it is necessary to ascertain whether there is a biological-genetic reality to race. If there is a biological-genetic reality to race, then there is a basis for attributing group differences to race. If not, then observed group differences on any factor under study cannot be described as race differences. The reasons for the discrepancy must be found in other explanations.

The short of it is that race, as we usually understand it, is a socio-political convention that has no basis in biological-genetic reality. It is a concept of classification that has utility for social and political purposes. Here is a quote from a paper, "Confusions About Human Races", by R. C. Lewontin:

"The every-day socially defined geographical races do identify groups of populations that are somewhat more closely similar to each other genetically. Most important from the standpoint of the biological meaning of these racial categories, however, most human genetic variation does not show such "race" clustering." -R.C. Lewontin is Alexander Agassiz Professor Emeritus of Zoology at Harvard University. He has written a number of books and articles on evolution and human variation, including Biology as Ideology: The Doctrine of DNA and The Triple Helix: Gene, Organism, and Environment.

Most of human genetic variation of all kinds, 85 percent, is observed in the immense differences among individuals. Most of those differences are found within local national and linguistic groups. As for the remaining 15 percent, it is split between differences between local national and linguistic groups (French vs Ukrainians), and the socio-political groupings. On top of this is the imprecision of categorizing people into the 'classical' race groups. Keep in mind that we are talking about all types of variation, not just IQ. Lewontin has argued, with plenty of data, that race is only skin deep.

2. Individual differences versus group differences

We have to distinguish between individual differences and group differences, especially when it comes to IQ. There is more than ample evidence to support a genetic component to differences among individuals on measured IQ. There are probably a number of factors that make up measured IQ, and there are probably a number of genes that contribute to these differences.

The problem arises when evidence of a genetic basis for individual differences is used to support claims of a genetic basis for group differences. This fundamental mistake is manifest even to this very moment in the discussion, here, on this issue. To most people, the argument seems plausible, if not downright obvious. The erroneous logic goes like this: Since genes influence IQ differences among individuals, then group differences on IQ must also have a genetic foundation. Nothing could be father from the truth.

The only way we could observe genetically based group differences of any kind, is if a group was able to breed in isolation, or relative isolation, for a long period of time. There is some evidence that Jews among the Ashkenazim, may have a higher IQ than other groups. If there is a genetic basis to this difference, it would have to be based on breeding in isolation (from members of other groups). This is a plausible explanation, though I am not familiar with the data. The West African peoples who became forced chattel in the Atlantic slave trade since the fifteenth century CE were hardly breeding in isolation, before or since.