[yummyfajitas]

Well, I admit, I just skimmed it, I'll try to read the whole thing later. But near as I can tell, he isn't addressing the validity of g at all, merely claiming it is unproven that genetic differences between population groups is due to genetics or other factors (a claim I don't disagree with).

[emmett]

You're right; sorry, wrong essay. The other one, by the same guy, addressing that point:

http://cscs.umich.edu/~crshalizi/weblog/523.html