Brad DeLong: belief

Transcript context

…Right. Up until the year 150, I think you can say yes. Although whether you can actually back that up with numbers you can semi-believe in really depends on what you see of the population evolution of humanity toward the end of the Bronze Age. There’s a fight between the Hyde people who think that Bronze Age empires were much more populous than others did, who think that the big increase in human settlement population and technology before the year zero came in the late Bronze Age with the Hittite and the Babylon and the Egyptian empires of the time. The rest of us tend to think that we see an acceleration with the coming of classical civilization as a whole in the Axial Age. I’m on the Axial Age side, but it’s disputed. After 150, though, things really do fall off a cliff, both in terms of the sophistication of high society and also in terms of the rate of increase of human population, at least Eurasia-wide. It’s not just that the Romans vanish from Britain, and it’s not just that the Latin language frontier gets pushed back so that it’s out of Britain completely and is moved 200 miles into France, as one elite succeeds another. It’s that there’s an enormous destruction of the mechanisms that were pushing ideas forward in the western, but also in the eastern Roman Empire, in Persia and in India, which are subject to repeated, fairly disastrous barbarian invasions, and the successor states never get back to the level of infrastructure and other investment and putting forward ideas about manipulating nature. In the fall of the Han Dynasty in China, and the Warring States period, and in the subsequent Tang Dynasty that you look . . . It isn’t until the Song arrive, and people start once again doing serious selective breeding with rice, that it looks like the rate of technology advance gets back in gear. I can’t convince myself that between 800 and 1500, the rate of growth of world technology was any greater than in the age of classical Persia and Greece and the coming of Han China, even though the population in 800 was three times what it had been when classical Greece started. So there’s a big interruption of the Romer story from 150 to 1500. Afterwards, it seems to me, it’s not so much two heads are better than one, but rather, we find and make much better institutions in fairly discrete steps. If we take your answer, which I largely agree with, it seems to me strikingly non-Malthusian. In the book, you seem much more a Malthusian, that the problem over the very long run is simply the ebbs and flows of population.…

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