Humans are a very young and a very homogeneous population. If there were a gene that unambiguously conferred greater intelligence without any associated cost, why would it not reach 100% penetrance in the population?
Typical Brit “Shakespeare didn't write any plays because he was a bloody commoner” elitism as well.
In Societies with entrenched social stratification there is little upward mobility and a great tendency to justify this based upon anything and everything. Here in the U.S.A. the ‘lower classes’ produce hard working and highly intelligent individuals who become billionaires.
"He said: "That is why such obvious scientific truths have not so far been stated clearly, or have actually been denied."
"(This theory is] accepted among those who know and understand the research."
I have a theory that IQ depends on if a mother holds her baby facing her so she can look in the baby’s eyes when she talks to him; or, if she holds her baby facing outward and never makes eye contact with him.