Edit:
I read a bit of Ned Block's piece. I believe he more or less immediately dismisses my view as "Extreme geneticism". While I don't agree that different groups in a given country grow up in the same circumstances, I also don't believe this matters much, if at all. If life teaches anything, it's that it's incredibly difficult to construct a machine that absolutely prevents the success of one group or another. Life is diverse and adaptable and finds a way. There are plenty of examples of groups historically facing terrible environments who nonetheless prospered.
Block also complains about a lack of sufficient data on the question of IQ. Fine, but one must immediately ask why there is such a lack of data. And that returns us to the demon-haunted world of quasi-religious opposition to such research.
Bottom line is, if you want to argue for the Rube Goldberg machine of -isms that produce differential outcomes in groups, prove it. I believe that, just as in other areas of human endeavor such as athletics, the prior should be that genetics are the most important input.