Assumptions:
Some conclusions that follow from these assumptions:
Therefore, different racial groups have a different average intelligence. This logic doesn't depend on what exactly you define as intelligence, as long as something is defined as intelligence. This logic doesn't imply that any particular racial group must have more intelligence than any other particular racial group. It just implies that by definition, individuals are different from each other and thus groups of individuals will also tend to differ in their different characteristics.
Now for the fun part.
Does it matter that different races have varying "average" intelligences? Only if you are racist and judge people by what arbitrary "race" you've mentally classified them as. To me, if you insist on classifying people based on their physical appearance, it would make more sense to classify people by height, or eye color, or their weight. Those attributes tend to make more of a difference, genetically.
However, perhaps you find race an easy way to filter individuals into categories. In that case, based on the extensive evidence, in some geographic regions, people with darker skin have a lower average intelligence as judged by the best tests and definitions of intelligence available. What's interesting is that in some other geographic regions, people with darker skin have a higher average intelligence.
So used as a bayes filter, skin color isn't going to typically give you the ability to improve your judgement of intelligence unless you have other demographic information that has a much better correlation.
In actual fact, if you want to judge a person's intelligence based on some quick rules of thumb, there are much better demographic methods available to you than skin color. National origins, wealth levels, education obtained (for older individuals), etc...
On the other hand, if you really care that much about it, just ask them to take whichever intelligence test you prefer for you.
But to say that races differ in intelligence? That statement should be as non-controversial as a statement of fact as it is useless as a guide to actions and policy.
Idang Alibi of Abuja, Nigeria writes on the James Watson affair:
An intriguing opening. Is Idang Alibi about to take a position on the real heart of the uproar?
Darn, it's just a lecture on personal and national responsibility. Of course, for African nationals, taking responsibility for their country's problems is the most productive attitude regardless. But it doesn't engage with the controversies that got Watson fired.
Later in the article came this:
This intrigued me for two reasons: First, I'm always on the lookout for yet another case of theology making a falsifiable experimental prediction. And second, the prediction follows obviously if God is just, but what does skin colour have to do with it at all?
A great deal has already been said about the Watson affair, and I suspect that in most respects I have little to contribute that has not been said before.
But why is it that the rest of the world seems to think that individual genetic differences are okay, whereas racial genetic differences in intelligence are not? Am I the only one who's every bit as horrified by the proposition that there's any way whatsoever to be screwed before you even start, whether it's genes or lead-based paint or Down's Syndrome? What difference does skin colour make? At all?
This is only half a rhetorical question. Race adds extra controversy to anything; in that sense, it's obvious what difference skin colour makes politically. However, just because this attitude is common, should not cause us to overlook its insanity. Some kind of different psychological processing is taking place around individually-unfair intelligence distributions, and group-unfair intelligence distributions.
So, in defiance of this psychological difference, and in defiance of politics, let me point out that a group injustice has no existence apart from injustice to individuals. It's individuals who have brains to experience suffering. It's individuals who deserve, and often don't get, a fair chance at life. If God has not given intelligence in equal measure to all his children, God stands convicted of a crime against humanity, period. Skin colour has nothing to do with it, nothing at all.
And I don't think there's any serious scholar of intelligence who disputes that God has been definitively shown to be most terribly unfair. Never mind the airtight case that intelligence has a hereditary genetic component among individuals; if you think that being born with Down's Syndrome doesn't impact life outcomes, then you are on crack. What about lead-based paint? Does it not count, because parents theoretically could have prevented it but didn't? In the beginning no one knew that it was damaging. How is it just for such a tiny mistake to have such huge, irrevocable consequences? And regardless, would not a just God damn us for only our own choices? Kids don't choose to live in apartments with lead-based paint.
So much for God being "just", unless you count the people whom God has just screwed over. Maybe that's part of the fuel in the burning controversy - that people do realize, on some level, the implications for religion. They can rationalize away the implications of a child born with no legs, but not a child born with no possibility of ever understanding calculus. But then this doesn't help explain the original observation, which is that people, for some odd reason, think that adding race makes it worse somehow.
And why is my own perspective, apparently, unusual? Perhaps because I also think that intelligence deficits will be fixable given sufficiently advanced technology, biotech or nanotech. When truly huge horrors are believed unfixable, the mind's eye tends to just skip over the hideous unfairness - for much the same reason you don't deliberately rest your hand on a hot stoveburner; it hurts.