Or one where the differences are small, or trivial. I don't think this is "miraculous" or "implausible". Before the invention of agriculture, about seven to twelve thousand years ago, I'm not sure what pressures there could have been on Europeans to develop higher intelligence than Africans, so in contrast to physical differences, many of which have well-established links to specific climates, intellectual genetic differences would probably be attributable to genetic drift and >~10,000 years of natural selection. To be clear, my position isn't that I have good evidence for this, merely that I don't know and I don't assign this scenario as low a prior probability as you seem to.