Do you think that a person with measured IQ of 70 is going to have just as foo (e.g. "easy a life", "much success", etc.) as a person with measured IQ of 130?

Do you think that a person with measured IQ of 70 is going to have just as foo (e.g. "easy a life", "much success", etc.) as a person with measured IQ of 130? Your overall position sounds to me like you want crisp, 1-bit, binary, black-or-white definitions or measures for everything, which is a pretty absurd demand. The real-world is n-bit. If you're looking for mathematically rigorous tools, fuzzy logic and probability theory help a lot in this area. The race problem isn't that hard qualitatively, either: part of the reason we say Obama is a black man is because he says he is himself, another reason is because his skin is more on the darker side of the human skin scale, without prior tanning, than others. You can come up with other reasons I'm sure. You can also go down to the genetic context if you wish, but I'm sure you know the public has been beaten over the head enough times for the past however many decades that race in a genetic context isn't quite as visible as in a visual or cultural context. (Depending on your samples, anyway.)