The best hypothesis I've heard IMO, is the genetic disposition of Homo Sapiens Sapiens to fall into two main categories of DNA distribution.

1. those with a large DNA component from Cromagnon Man (large brain), and
2. those races with a large DNA component of Homo Erectus.
   Statistically, there can be outliers in any modern racial group. However, mean I.Q of racial groups and its correlation with DNA percentiles related to the two hominid groups mentioned, is conclusive and makes a lot of sense about the state of world affairs. Not only that, it's pretty bloody interesting!

So many forms of "group-think" are dangerous. Obviously, white supremacists formulate part of their narrative around race, but they use other poorly formulated arguements as well. What I didn't like about the article is that many people use race to formulate narratives that serve their own purposes. To use the article only to focus on white supremacists limits its effectiveness and makes the author look like he/she has a specific agenda. This article also ignores the fact that race is just one of many social constructs that can encourage dangerous forms of "group-think" that can pull a society apart.

Oh, yes, this is absolutely true. I'm not a scientist but I'm educated enough to know that there is no such thing as "racial purity" and that even the concept "race" is not considered scientifically valid.

I think it's indisputable that there are racial markers that are observable (just as there are observable markers between men and women - generally). I agree that there are few "pure" races (isolated rain forest dwellers may come close). This debate misses the point. On a normal distribution there is more variability along most measurable dimensions within any identifiable group than there are between groups. Race is not a social construct but our assigning certain types of characteristics to a group is. We must be much more vigilant in our thinking to discern the difference between what the science is vs what we want it to say about some particular issue.