> "Gorillas have had ample free time to build their own Parthenon, had they wanted to."
I think he actually mentioned a possible reason
Therefore, there can be no kings, no class of social parasites who grow fat on food seized from others
that's engineers and artists and thinkers. They can completely specialize in what they do because they don't have to work to get food. Usually it was because they had a Maecenas who exploited legions of other people to provide (mainly) for himself and (a little) for people who he found interesting (or they provided him with entertainment). And those people created the most innovation, I believe. Innovative farmers would be concerned with how to work on the field so that their backs hurt less, but major advances required seeing the bigger picture.
In 3000 BC, artists, thinkers, lawyers, doctors and engineers (to what extent they existed) were all part of one (mostly parasitic, but in some ways quite useful) caste: priests.
People tend to think of ancient priests as charlatans, but they were also the people who held onto all the knowledge: that if you chew these "magical" leaves while tilling the fields, you don't get tired; if you plant when this "divine" star is rising, you get the best results. The emergence of artists, engineers, et al, apart from a priesthood didn't emerge until the birth of philosophy in the first millennium BC.
I think he actually mentioned a possible reason
Therefore, there can be no kings, no class of social parasites who grow fat on food seized from others
that's engineers and artists and thinkers. They can completely specialize in what they do because they don't have to work to get food. Usually it was because they had a Maecenas who exploited legions of other people to provide (mainly) for himself and (a little) for people who he found interesting (or they provided him with entertainment). And those people created the most innovation, I believe. Innovative farmers would be concerned with how to work on the field so that their backs hurt less, but major advances required seeing the bigger picture.