6 ideas
Humans can have true, causal knowledge only of what they themselves have made, since the maker knows the causes of the thing. Because nations, laws and institutions are human creations, the civil world is more knowable to us than the natural world, which only God, its maker, fully understands.
Every nation passes through an age of gods, where people read divine will in nature and are ruled by priests and oracles, then an age of heroes, where aristocratic lineages claim superior nature and rule by force, then an age of men, where people recognise their shared human nature and live under equal laws and reason. Each age has its own matching language, jurisprudence, government and kind of authority.
A civilisation at its rational peak decays as critical intellect dissolves shared custom and piety into private self-interest, producing a 'barbarism of reflection' crueller than the original barbarism of the senses. This collapse returns the society to a primitive condition from which the cycle of ages begins again, as Europe did in the medieval period after Rome fell.
Read early fables not as lies or allegories hiding philosophical wisdom but as literally true histories of the first peoples' customs, recorded in the only form their imagination-dominated minds could produce. Gods and heroes are 'imaginative universals': figures such as Jove or Hercules that fold a whole class of experiences or social roles into one concrete character.
After the flood, scattered giant-like humans heard thunder for the first time and, imagining the sky as a vast animate body, took it as a god, Jove, speaking to them in signs. Terror of that sky drove them into caves, where they formed settled unions with women, and so religion, marriage and burial of the dead began together as the first civil institutions.
The first humans were poets rather than reasoners, thinking through the senses, the body and imagination, so 'poetic wisdom' existed long before abstract rational wisdom. Scholars err with the 'conceit of scholars' and the 'conceit of nations' when they assume ancient peoples thought as modern learned people do or that their own nation originated civilisation.