Suppose, for the purposes of argument, HBD (Human bio-diversity, the claim that distinct populations (I will be avoiding using the word "race" here insomuch as possible) of humans exist and have substantial genetical variance which accounts for some difference in average intelligence from population to population) is true, and that all its proponents are correct in accusing the politicization of science for burying this information.

I seek to ask the more interesting question: Would it matter?

1. Societal Ramifications of HBD: Eugenics

So, we now have some kind of nice, tidy explanation for different characters among different groups of people.  Okay.  We have a theory.  It has explanatory power.  What can we do with it?

Unless you're willing to commit to eugenics of some kind (be it restricting reproduction or genetic alteration), not much of anything.  And even given you're willing to commit to eugenics, HBD doesn't add anything  HBD doesn't actually change any of the arguments for eugenics - below-average people exist in every population group, and insofar as we regard below-average people a problem, the genetic population they happen to belong to doesn't matter.  If the point is to raise the average, the population group doesn't matter.  If the point is to reduce the number of socially dependent individuals, the population group doesn't matter.

Worse, insofar as we use HBD as a determinant in eugenics, our eugenics are less effective.  HBD says your population group has a relationship with intelligence; but if we're interested in intelligence, we have no reason to look at your population group, because we can measure intelligence more directly.  There's no reason to use the proxy of population group if we're interested in intelligence, and indeed, every reason not to; it's significantly less accurate and politically and historically problematic.

Yet still worse for our eugenics advocate, insomuch as population groups do have significant genetic diversity, using population groups instead of direct measurements of intelligence is far more likely to cause disease transmission risks.  (Genetic diversity is very important for population-level disease resistance.  Just look at bananas.)

2. Social Ramifications of HBD: Social Assistance

Let's suppose we're not interested in eugenics.  Let's suppose we're interested in maximizing our societal outcomes.

Well, again, HBD doesn't offer us anything new.  We can already test intelligence, and insofar as HBD is accurate, intelligence tests are more accurate.  So if we aim to streamline society, we don't need HBD to do so.  HBD might offer an argument against affirmative action, in that we have different base expectations for different populations, but affirmative action already takes different base expectations into account (if you live in a city of 50% black people and 50% white people, but 10% of local lawyers are black, your local law firm isn't required to have 50% black lawyers, but 10%).  We might desire to adjust the way we engage in affirmative action, insofar as affirmative action might not lead to the best results, but if you're interested in the best results, you can argue on the basis of best results without needing HBD.

I have yet to encounter someone who argues HBD who also argues we should do something with regard to HELPING PEOPLE on the basis of this, but that might actually be a more significant argument: If there are populations of people who are going to fall behind, that might be a good argument to provide additional resources to these populations of people, particularly if there are geographic correspondences - that is, if HBD is true, and if population groups are geographically segregated, individuals in these population groups will suffer disproportionately relative to their merits, because they don't have the local geographic social capital that equal-advantage people of other population groups would have.  (An average person in a poor region will do worse than an average person in a rich region.)  So HBD provides an argument for desegregation.

Curiously, HBD advocates have a tendency to argue that segregation would lead to the best outcome.  I'd welcome arguments that concentrating an -absence- of social capital is a good idea.

3. Scientific Ramifications of HBD

Well, if HBD were true, it would mean science is politicized.  This might be news to somebody, I guess.

4. Political Ramifications of HBD

We live in a meritocracy.  It's actually not an ideal thing, contrary to the views of some people, because it results in a systematic merit segregation that has completely deprived the lower classes of intellectual resources; talk to older people sometime, who remember, when they worked in the coal mines (or whatever), the one guy who you could trust to be able to answer your questions and provide advice.  Our meritocracy has advanced to the point where we are systematically stripping everybody of value from the lower classes and redistributing them to the middle and upper classes.

HBD might be meaningful here.  Insofar as people take HBD to its absurd extremes, it might actually result in an -improvement- for some lower-class groups, because if we stop taking all the intelligent people out of poor areas, there will still be intelligent people in those poor areas.  But racism as a force of utilitarian good isn't something I care to explore in any great detail, mostly because if I'm wrong it would be a very bad thing, and also because none of its advocates actually suggest anything like this, more interesting in promoting segregation than desegregation.

It doesn't change much else, either.  With HBD we continually run into the same problem - as a theory, it's the product of measuring individual differences, and as a theory, it doesn't add anything to our information that we don't already have with the individual differences.

5. The Big Problem: Individuality

Which is the crucial fault with HBD, iterated multiple times here, in multiple ways: It literally doesn't matter if HBD is true.  All the information it -might- provide us with, we can get with much more accuracy using the same tests we might use to arrive at HBD.  Anything we might want to do with the idea, we can do -better- without it.

HBD might predict we get fewer IQ-115, IQ-130, and IQ-145 people from particular population groups, but it doesn't actually rule them out.  Insofar as this kind of information is useful, it's -more- useful to have more accurate information.  HBD doesn't say "Black people are stupid", instead it says "The average IQ of black people is slightly lower than the average IQ of white people".  But since "black people" isn't a thing that exists, but rather an abstract concept referring to a group of "black persons", and HBD doesn't make any predictions at the individual level we couldn't more accurately obtain through listening to a person speak for five seconds, it doesn't actually make any useful predictions.  It adds literally nothing to our model of the world.

It's not the most important idea of the century.  It's not important at all.

If you think it's true - okay.  What does it -add- to your understanding of the world?  What useful predictions does it make?  How does it permit you to improve society?  I've heard people insist it's this majorly important idea that the scientific and political establishment is suppressing.  I'd like to introduce you to the aether, another idea that had explanatory power but made no useful predictions, and which was abandoned - not because anybody thought it was wrong, but because it didn't even rise to the level of wrong, because it was useless.

And that's what HBD is.  A useless idea.

And even worse, it's a useless idea that's hopelessly politicized.