>>4720137>>4718275Not that valid. Intelligence, as tested, is simply what intelligence tests measure. You can consider them some kind of ruler, but then for what we call intelligence.
And there are plenty of decent 'rulers' available, that you can compare populations on.
It doesn't have to measure perfectly, as long as it doesn't suffer from huge error variance. (If you generally measure the same thing, amongst the different people, with roughly the same amount of error)
Not to mention that large differences are generally robust even against rulers that do have a moderate amount of measuring error.
The difference simply does not exist.