Recently, Richard Hoste discused the decline of the West in terms of biohistory. It’s a rather simplistic and reductionist take, but it’s nonetheless interesting for what it is. For a richer perspective on societal systems and their rise and recess, I would refer one to Peter Turchin’s Cliodynamics.
The intelligent tribe’s population grows. More people means more inventions. The population then grows further, because people still have their old habits and haven’t yet realized that more children means a lower standard of living. The “Flynn Effect”, an absolute rise in IQ likely caused by improved nutrition, takes hold and people become even smarter.
Thus although high intelligence is no longer selected for, improvements in environment mask any decline in the gene pool. The society’s higher IQ leads to even greater progress.
But this doesn’t go on forever. There is only so much that nurture can do to improve cognitive functioning. So, although IQ improved by about thirty points in the twentieth century, with most of the gains coming at the middle and left of the bell curve, the Flynn Effect has now hit its limits in the modern West.
Finally decadence sets in. Hedonism, feminism and materialism are the preferred values. Faith declines, and scientific (or at least scientistic) arguments replace religious and magical ones. The population drops as people smart enough to plan ahead limit their fertility in order to have more money for self-fulfillment.
Meisenberg quotes Spengler:
“Children do not happen, not because children have become impossible, but principally because intelligence at the peak of intensity can no longer find any reason for their existence…When the ordinary thought of a highly cultivated people begins to regard ‘having children’ as a question of pro’s and con’s, the great turning point has come. For nature knows nothing of pro and con.”
See this video from Iranian TV mocking Westerners for treating the decision to have children as one treats the decision to buy a dog or cat.
But the stupid and irresponsible continue to breed away, as compassion and medical advancement make sure that almost anyone who is born lives to pass on his genes. Instead of the eugenic Flynn effect, we see dysgenics. Civilization collapses and people go back to their original primitive state.