It is hard to evaluate the issue of intelligence. It is important to see that the way we conventionally take it doesn’t work.
More generally a look at the eonic effect shows the way creative advance is clustered in particular intervals. We have an immense technological civilization but a close look shows that the genesis of that was in the early modern in its most fundamental aspect and that it declined after that.
We can see that the usual descriptors of ‘intelligence’ don’t really work because the larger view of history shows something unexpected. And we must consider the very high intelligence of the creative explosion of archaic/classical greece followed by its gross decline into roman barbarism an ominous warning of what is likely to happen again in the modern time frame.
The recent craze for Pete Buttigieg — multilingual Rhodes Scholar and all-around smart guy — is just the latest incarnation of the meritocratic cult of “smartness.” It’s social Darwinism for liberals.