A general feature of many scientific endeavors is to measure $CARDINAL_PROPERTY across $CATEGORY - beak length across birds, speed across big cats, lifetime across mammals, etc. Do you oppose all these fields of inquiry, e.g. ranking stars by their brightness?

Or are these questions merely forbidden to ask about humans, due to some privileged position granted to us by god (or whatever)?

I would frame your objection a bit differently: finding an Asian IQ advantage is in no way incompatible with racism or white supremacism. Many of these guys (Rushton for example) believe that Asians are inferior in areas other than IQ.

Do you know if Rushton's beliefs that Asians are inferior in other areas are based on experiments? I'd be interested in any links you might have.

> It doesn't change the basic purpose of the endeavor, which is to purport to rank the peoples of the world by intellectual capacity.

Based on this statement, I suspect our fundamental disagreement is over whether it does more harm than good to consciously deny empirical evidence for something when it has the potential to be spun into harmful propaganda. My position is that, while saying some true things can lead to harm in this way, it's more damaging to suppress or deny this information. How can it possibly be more damaging to forbid people from saying something inflammatory, like "Asians are smarter than Europeans" or "Europeans are smarter than Africans", than to allow it? Because the biggest gift you can give someone with a harmful agenda is something that looks to the untrained eye like a rational argument with solid empirical support, and then attempt to silence them.

You might bristle, but, according to studies I've seen, a white supremacist is not actually wrong when s/he announces that "Black people are on average less intelligent than white people!". What is wrong is the implication that they intend: that black people therefore deserve less respect/money/rights/something than do white people. As I see it, by trying to make discussion of the empirical data itself taboo, well-intentioned equality-minded people are only feeding the mistaken belief that, were there to be a genuine, measurable difference, the implication of being less deserving would follow. Not only is this false, it gives the supremacist more firepower: they can now truthfully claim, in addition, that "Liberals don't want this information to be known!".

One of the underexamined issues here is the special role of intelligence in the popular understanding of what it means to be human. We aren't threatened to the same extent by people drawing group-level distinctions based on, say, athletic ability. Our attachment to the idea of intelligence as central to humanity is, I believe, simply an unfortunate habit of mind. Fortunately, we're not totally governed by it: we don't put a murderer in prison longer if they murder someone highly intelligent. We already collectively agree that there are fundamental things to which we're all entitled based on nothing more than our humanity. (It's unfortunately true that there are many gaps and inconsistencies still in existence, but my point is that we aspire to treat people equally in these respects regardless of intelligence, and that in some cases at least, we achieve it.)

This is the right way forward, I believe. We need to create a widespread understanding that, even if average-level group differences exist in traits as beloved as intelligence, this would not imply anything about that person morally -- that is, about what that person deserves in life. With this in place, a supremacist's boasts about their race's intelligence have no more recruiting power than yelling out "Black people have darker skin than white people!" or "An object at rest tends to remain at rest!", or any other empirically demonstrable fact.

I must object. Nobody knows how to define or measure "intelligence." When you/they say "intelligence" what is actually being discussed is a specific artificial measure that's meant to indicate what we consider "intelligence," with varying amounts of success.

In addition to the general problems of defining and measuring "intelligence," which nobody really understands how to do, there's also the more specific problem that the techniques developed so far are often biased against minorities.

There's also the problem of cause. The racist crazies tend to interpret any difference as "Disliked Minority X is inherently less intelligent," even though it's almost impossible to distinguish between differences caused by nature versus nurture. If differences are real, how much is due to genetics and how much is due to being oppressed for generations and therefore receiving inferior education and opportunities?

Finally, even if there were a difference, and even if it were inherent, there's the problem of group versus individual. To make this more concrete, let's momentarily ditch intelligence and look at something more morally clear, like propensity for violent crime. Let's say it's demonstrated incontrovertibly that purple people are 10x more prone to violent crime than green people. That still doesn't justify systematic discrimination against purple people, even though the data is clear and the morality of the difference is clear, because individuals matter. Just because purple people are more likely on average to be violent criminals doesn't mean any individual one is. To justify different treatment based on race, you'd have to show that every purple person was this way, which is simply not true.

When it comes to real-world intelligence in real-world races, it's even less relevant, because variation within groups far outweighs variations between groups. Even if it was demonstrated that intelligence varied between races and even if it was decided that lower intelligence somehow merits bad treatment, this still wouldn't justify systematic racism.

In short, there are a bunch of different questions:

1. What are we even measuring?

2. Does a difference even exist?

3. Does that difference justify different treatment?

4. Does a group-level difference justify prejudging individuals within the group?

You seem to be concentrating on #3 exclusively. While it's a fascinating question, I also think it's the least relevant to questions of race, precisely because individual differences far outweigh even the craziest speculated differences by fevered racists. The question of how to deal with people of different intelligence is a good one, but it tells us virtually nothing about race relations as compared to e.g. how to set up Special Education programs.