Update: Well, that was a disappointment. Here's Brad's premise for his entire argument:
I've come to agree with the assumption that there are no biological differences between races of Homo sapiens. That we measure a difference in IQ is thus an unexpected result.As it turns out, this once fashionable consensus is being taken over by the data. And even though Brad's not giving up the ghost quite yet, the experts he's relying upon already have. (See also response #7 of this recent interview)
So, in fact, there are biological differences, such as different skin colors, tolerance to types of food, resistance to pathogens, facial characteristics, body types, and the like, between human populations. Such differences make differences in IQ in these populations not unexpected.
Without this premise, Brad has no argument. (Brad, that's a little trick I learned in law school, not in science school.)
The take away is that biologically based cognitive differences exist between people that may not be rectifiable through environmental interventions (such as SES doctoring). Someday we may know more about improving cognitive ability through environmental interventions, but today is not that day. Today, we need to accept the reality that a sizable portion of our child population has a diminished cognitive capacity. They need to be educated today using proven techniques, not speculative Rothstienian twaddle based on outdated politically correct consensus "science."
Update 2: Brad has now shut down any further commenting on this issue. In any event he has posted some links to the somewhat recent Turkheimer study, the misinterpretation of which is explained here, here, and here. And, also, here. Here too. I suppose that's why the comments were shut down. Damn those pesky facts.