Writing about intelligence is like running a ferry service between two different planets.

On one, everyone assumes that g, general intelligence, is a real and important trait, in which heredity plays a big role, and which is accurately measured by tests. On the other planet, g is a social and historical phenomenon--a belief one set of people have about themselves, or about other people. Most of the time the natives on each world speak happily only to each other. When you land with your news of the other place, the usual reactions are incredulity (those people don't exist!), anger (no one can believe that!) and/or a droning recitation of the sacred texts (please see these 114 papers listed below). See the comments on my Pinker-Gladwell post for examples.

Is it possible to foster communication between these two worlds? It seems like a job for serious journalism. Yet those who venture into the subject end up being flamed as shills for one side or the other.

Maybe a better approach is to describe controversies within each school, as that's probably where the ratio of thought to rhetoric is highest. Here's a case in point (and thanks to Frank Forman for cluing me in): there's a controversy over whether it is possible to say that a nation has a stable and characteristic level of intelligence.

On Planet History, this idea wouldn't be taken seriously for a minute, because it claims today's Egyptians, Jews and Asians are identical with their ancestors (at least for the important trait of intelligence). As Patricia Cohen explains here, historians and anthropologists know that any people's ties to its ancestors are a combination of fact, myth and selective emphasis, re-created in each lifetime, and shaped by the needs of the moment. This cultural activity occurs on top of the genetic facts, and is not congruent with them. While there are genetic differences between populations in the Middle East, those contrasts don't follow the same borders as the cultural ones.

For example, Patricia Cohen's last name is traditionally associated with descendants of the kohanim, the priestly caste of Biblical Judaism. A decade ago a team of geneticists found a genetic marker common in men who identified themselves as kohanim. But the "Cohen Modal Haplotype" is also found in some Yemenites, Uzbeks and Italians. Addressing that fact, the discoverers recently reported that they've created a more precise marker, which is found only in Jews. That is significant news at the genetic level of analysis--but it doesn't change the fact that there are many Jews who are kohanim but who don't have the genetic marker. They remain kohanim because kohan is a cultural concept, not a genetic one.