[A_D_E_P_T]

"Goons." Nice.

Thing is: Are you absolutely sure that notion of human biodiversity is wrong? IQ is heritable, as height is heritable. You'll grant that there are populations that differ in their genetic potential for height -- e.g. Dalmatians vs. Pygmies -- so how is it that you dismiss out of hand the notion that there might be population-wide differences in the genetic potential for intelligence?

I can hear it now: "But IQ is not intelligence!" I agree to a point, but IQ -- and, strangely, verbal IQ in particular -- maps very neatly to one's potential for achievement in all scientific and technological fields.

The Truth is a jealous goddess: If you devote yourself to her, you must do so entirely, and take the bad along with the good. You don't get to decide what's out of bounds; no field of inquiry should be off-limits.

[tptacek]

What do you think heritability means?

[A_D_E_P_T]

Farmers, who depend on this sort of thing, have it figured out:

> https://extension.missouri.edu/publications/g2910

Heritability is simply a measure of how much of the variation in a trait, like height or IQ, is due to genetic factors rather than environmental influences in a given population. Could be feedlot steers, could be broiler chickens, could be humans. In humans, traits like height are very highly heritable, at ~0.8. Certain others, like eye color, are heritable to ~0.98.

[tptacek]

Right. It's a simple ratio of genetic variation to phenotypical variation. How does evidence of heritability support HBD claims, which are based on genetic determinism, a notion orthogonal to heritability?

[A_D_E_P_T]

I don't think that HBD claims -- at least, those made in reasonably good faith -- are based on genetic determinism. A Bosnian guy from the Dinaric alps is much more likely to be >1.8m in stature than a Pygmy. This is not predetermined as such, it's just that one population has something like +3SD in stature over the other. (An admittedly wildly extreme example!)

Differences in IQ between groups are apparently far more modest, but, however distasteful, it's still possible to speak of them, and it's possible to make statistical statements about them. My position is simply that, on the one side, it should be done in good faith -- and, on the other side, it shouldn't be seen as something heretical.

[tptacek]

I don't understand the alternative interpretation you're alluding to. Stipulate the validity of IQ or the common g. If group variations in these metrics aren't caused by genes, why are they distasteful? If they are, you're describing genetic determinism, which, again, is orthogonal to heritability.

[A_D_E_P_T]

Heritability is a statistical concept, not a measure of genetic determinism. High heritability doesn’t imply that a trait one exhibits, such as IQ or height, is entirely predetermined by one's genes. Even eye color is only heritable to ~0.98. I'll grant that any trait heritable to 1.0 is indeed entirely predetermined by one's genes -- though, offhand, I'm not sure that such traits exist in humans.

That aside, we're getting into semantics. Whether you call it "genetic determinism" or "heritability," we're talking about durable group differences in genetically-mediated traits. And that is what people may find distasteful or even heretical.