There is a big difference between raw intelligence, such as IQ tests measure, and education.
You can pour a lot of energy into trying to educate people with IQs of 75 and not achieve much. This is known among liberals as the mysterious “achievement gap”, which to them is completely mysterious.
Europeans started inhabiting Europe somewhere between 25,000 and 50,000 years ago. Among other factors the ice age probably increased the intelligence of the proto-Europeans, by forcing them to find new ways to survive.
I find it hard to believe that you state in one post that Christianity cannot make people more intelligent but then credit the ice age with increasing the intelligence of the “proto-Europeans”. Are you saying that God has no power to expand the mind of man but that “mother nature” does? This would seem to defy Scripture...
Proverbs 1:7 The fear of the Lord is the BEGINNING of knowledge, but fools despise wisdom and discipline.
Proverbs 2:6 For the Lord gives wisdom, and from his mouth come knowledge and understanding.
Proverbs 9:10 The fear of the Lord is the beginning of wisdom, and knowledge of the Holy One is understanding.
Proverbs 15:33 The fear of the Lord teaches a man wisdom, and humility comes before honor.
I could go on...