[I am] "inherently gloomy about the prospect of Africa" because "all our social policies are based on the fact that their intelligence is the same as ours -- whereas all the testing says not really".This comment is clearly politically incorrect and probably scientifically incorrect. As Joseph Conrad points out in Heart of Darkness, the difference between European and African civilization is a matter of years, perhaps centuries - but not of evolutionary time.
But it remains highly probable (for reasons related to the Law of Large Numbers) that at least one scientific study, correctly executed, will show that one race is genetically superior to another on a dimension such as intelligence. We already know that races differ in physical dimensions, such as height and hairiness. What effectively prevents the scientific community from finding genetic differences in intelligence, criminality, alcohol-proneness, etc., is that it really, really doesn't want to.
Something must give. Either we engage in science dishonestly, construing results to fit our prejudices (however noble), or we submit our values to scientific evaluation. This Morton's fork could literally lead to the dismantling of one or another of the pillars of our Enlightenment civilization.
However, it need not. By subjecting our values to a standard higher than scientific objectivity, we can maintain civilization as we know it.
Only recently have standards higher than science been eroded in human civilization. To a great extent we still practice them: we protect the sick and disabled rather than abandoning them; we do not discriminate (openly) between the children of smart people and the children of dumb people; we do not practice euthanasia. Any of these could be discarded in the name of science: spending valuable resources giving a classical education to children regardless of their genetic potential is a huge waste, statistically, to offer one example.
Why do we - and why should we continue to - protect and honor all of humanity? Because some values are informed by a conscience greater than science.
We as a civilization need not agree the source or content of all these values, provided we agree they exist and come to some compromise on a subset of them. When we are secure in our underlying conscience, we can look research in the eyes - even if it tells us something very unpleasant.
Suppose, counterfactually, that Dr. Watson (insert, "elementary, my dear" joke here) is correct. We can openly discuss and acknowledge the findings. Then, after testing and re-testing the hypothesis many times, we may be forced to alter our social policies in order to attain the goals dictated by our conscience. But we need never alter our conscientious values: that people are responsible for their own self-government, that they are equal in dignity and rights, and that their thoughts should be free and freely expressed.