Where do you start? I start with a very crude global index of the value of the stock of human technology—useful ideas about manipulating nature and productively organizing humans—that have been discovered, developed, and then deployed-and-diffused throughout the world economy. How do you construct this index? I calculate it as the average worldwide level of income per capita, times the square root of population. Why “square root”? The square-root recognizes that there is resource scarcity—hence generating income for more people is burdensome, and so the technology level is not simply average output per capita—but also that each mouth comes with two eyes, two arms, and a brain, so that labor is productive—hence total world product is not the technology level either. “Square-root” is a balance. Would you die on the hill that it is square-root, rather than some other power between 0 (which gives average income per capita) or 1 (which gives total world product) multiplying population? No. What do your guesses—I won’t call them numbers—then show, in terms of the annual average proportional growth rates of technology deployed-and-diffused, worldwide? Roughly: growth very slow for millennia—visible only in la longue durée—then growth visible over a human lifetime, barely, after 1500; growth substantial over a human lifetime after 1770; and then growth so that humanity’s technological prowess doubles every generation after 1870.:
I appreciate your description of the process of constructing your knowledge index. You've been throwing it around for several years but its source was never clear.
Regarding the -1000 to 100 Axial-Iron age periodization. I've been struck by the adoption of iron-making technology apparently leading to ethnic expansion. So first, the Greek and Pubic expansion throughout the Mediterranean. This was followed by the Celtic expansion several hundred years later. Then came the Italic expansion, the Germanic expansion. Also the Bantu expansion in Africa. It occurred to me as I write that the Persian expansion may be the first instance. I don't know enough about East Asian history to know if the Hunnish, Avar, Magyar, and Mongolian expansions were similarly triggered. I believe this actually suggests the migration is one of the means to (temporarily) escape Malthus.
I've noted previously that the expansion of Eurasian style intensive agriculture across North America and the migration of surplus European population to the west held open the jaws of the Malthusian trap long enough for the takeoff of 1870. Of course, there was surplus population because of the Columbian exchange gave Europeans maize and potatoes.
Gosh this is fun, Brad. Could you please write another magnum opus for us to enjoy thinking about and discussing.
If the human-technological-flourishing growth pattern is exponential, then any amount of recent epidemiology has taught us that there is nothing special about the moment when the hockey stick curves upwards - it's just a matter of time and the R number.
If you stood in any of these historical eras looking back with this index in hand and no knowledge of the future I think you'd find a Big Important Change in the previous era that contributed to the uniquely extraordinary pace of growth in your era; where growth had peaked and stalled Late Antiquity Pause you would be able to hark back to the extraordinary height of human technological flourishing and discuss the Big Important Change that led to it.
(swa nu missenlice just as now intermittently
geond þisne middangeard around this Earth
winde biwaune wound about with wind,
weallas stondaþ, walls stand,
hrime bihrorene, wrapped about with ice,
hryðge þa ederas. the storm's buildings.
...
eald enta geweorc the old giants' work
idlu stodon. stood useless.)
If human technological growth continues to accelerate, in 20 or 40 years time one could look back and say "the Big Important Change, of course, was the climate-change driven flourishing of low-cost, low-impact energy sources that led to the modern world of incredibly cheap abundant energy" (or "was the arrival of Artificial General Intelligence and the inauguration of the Culture"... or in less optimistic versions we've hit some other peak, possibly the hard way by chucking nuclear weapons about, and are harking back to the lost golden era of the early C21st from round our pitiful campfires in the waste).
Big Important Changes are ten a penny, easily retrofitted onto any part of the curve, and equally interesting at every stage - but while more recent growth acceleration may be quantitatively different from previous eras (and quantity does have a quality all of its own), I'm not sure that the most recent shift in dynamics is super special and unique any more than the people who happen to be alive today are super special and unique compared to our ancestors.
I appreciate your description of the process of constructing your knowledge index. You've been throwing it around for several years but its source was never clear.
Regarding the -1000 to 100 Axial-Iron age periodization. I've been struck by the adoption of iron-making technology apparently leading to ethnic expansion. So first, the Greek and Pubic expansion throughout the Mediterranean. This was followed by the Celtic expansion several hundred years later. Then came the Italic expansion, the Germanic expansion. Also the Bantu expansion in Africa. It occurred to me as I write that the Persian expansion may be the first instance. I don't know enough about East Asian history to know if the Hunnish, Avar, Magyar, and Mongolian expansions were similarly triggered. I believe this actually suggests the migration is one of the means to (temporarily) escape Malthus.
I've noted previously that the expansion of Eurasian style intensive agriculture across North America and the migration of surplus European population to the west held open the jaws of the Malthusian trap long enough for the takeoff of 1870. Of course, there was surplus population because of the Columbian exchange gave Europeans maize and potatoes.
Gosh this is fun, Brad. Could you please write another magnum opus for us to enjoy thinking about and discussing.
Why must there be a Big Important Change?
If the human-technological-flourishing growth pattern is exponential, then any amount of recent epidemiology has taught us that there is nothing special about the moment when the hockey stick curves upwards - it's just a matter of time and the R number.
If you stood in any of these historical eras looking back with this index in hand and no knowledge of the future I think you'd find a Big Important Change in the previous era that contributed to the uniquely extraordinary pace of growth in your era; where growth had peaked and stalled Late Antiquity Pause you would be able to hark back to the extraordinary height of human technological flourishing and discuss the Big Important Change that led to it.
(swa nu missenlice just as now intermittently
geond þisne middangeard around this Earth
winde biwaune wound about with wind,
weallas stondaþ, walls stand,
hrime bihrorene, wrapped about with ice,
hryðge þa ederas. the storm's buildings.
...
eald enta geweorc the old giants' work
idlu stodon. stood useless.)
If human technological growth continues to accelerate, in 20 or 40 years time one could look back and say "the Big Important Change, of course, was the climate-change driven flourishing of low-cost, low-impact energy sources that led to the modern world of incredibly cheap abundant energy" (or "was the arrival of Artificial General Intelligence and the inauguration of the Culture"... or in less optimistic versions we've hit some other peak, possibly the hard way by chucking nuclear weapons about, and are harking back to the lost golden era of the early C21st from round our pitiful campfires in the waste).
Big Important Changes are ten a penny, easily retrofitted onto any part of the curve, and equally interesting at every stage - but while more recent growth acceleration may be quantitatively different from previous eras (and quantity does have a quality all of its own), I'm not sure that the most recent shift in dynamics is super special and unique any more than the people who happen to be alive today are super special and unique compared to our ancestors.