Life goes nuclear

2.06 – 1.95 Gya

Eukaryotic cells (Domain Eucaryota, which includes multicellular life, like plants, animals, and fungi) are, on average, much larger and more complex than the earlier evolved prokaryote cells (Domains Bacteria and Archaea*). They have organelles, including mitochondria that power them and chloroplasts (at least among plants) that carry out photosynthesis. Their DNA is stored in a nucleus, and consists not just of genes (as in prokaryotes), but of large stretches of non-coding DNA (most of their genome), separating pieces of genes. The ancestor of present-day eukaryotes reproduced sexually, although some eukaryotes have since given up sex.

There are different ways that life increases in complexity. The origin of the Eucarya has something in common with a much later event, the origin of agriculture (check out September 11 on logarithmichistory). Starting 10,000 years ago, we Homo sapiens brought other animals and plants under our control, managing their reproduction, and selecting them (first unintentionally, then intentionally) to suit our purposes, until now most domesticated creatures couldn’t survive in the wild. Our own numbers and social scale increased enormously with the rise of agriculture.

At least 2 billion years ago, an archaeon cell gobbled up one or more bacterial cells (or was parasitized by them). The bacteria ended up surviving inside it, and after many generations became a kind of domesticate inside their host. Eukaryotes do domestication one better than humans: they carry their livestock inside their bodies. Eventually this domesticate evolved into mitochondria, the little power packs that pump out ATP for the rest of the cell to use as as an energy source. Over the course of time all but a small fraction of the original bacterial genome was moved into the nucleus.

In the last few years we have come closer to understanding how this momentous step occurred: we have discovered a new branch of the Archaean tree, the Asgard archaea. The Asgard archaeans carry some genes otherwise found only in eukaryotes, and it looks likely the first eukaryote to start hosting the bacterial ancestors of mitochondria was either an Asgarder, or close branch. Just recently we finally succeeded in cultivating these creatures in the lab. (It was hard to do.) They are tiny little spheres with long filaments protruding from them. The partnership between Archaeans and bacteria may have begun with bacteria nestling in these protrusions.

Humans developed agriculture multiple times independently around the world. As far as we know, eukaryotes evolved only once, long after the origin of simpler forms. The evolution of eukaryotes might be very unlikely to occur during the habitable lifespan of a planet. The observable universe may be full of bacteria, but harbor more complex cells only sparsely.

* Domain Archaea, a billions-of-years-old group of single-celled organisms looking like bacteria but biochemically different, should not be confused with the Archaean Eon, a billions-of-years-long stretch of Earth history.

Green revolution

November 1970 – August 1974

The battle to feed all of humanity is over. In the 1970s hundreds of millions of people will starve to death in spite of any crash programs embarked upon now. At this late date nothing can prevent a substantial increase in the world death rate.

Paul Ehrlich. The Population Bomb. 1968

Ironically, it was just around the time that Ehrlich wrote this that production of rice and wheat in India, the Philippines, and other countries was booming thanks to the Green Revolution – more productive plant varieties that could take advantage of fertilizer and pesticide inputs. It’s true, as Malthus pointed out long ago, that exponential population growth can eat up any conceivable increase in agricultural output. But the Green Revolution bought the world some breathing space until birth rates began to come down. It probably also eased some of the paranoia about food supply that played a part in two world wars, and the rural discontent that fueled earlier peasant revolutions.

Norman Borlaug, Green Revolution pioneer, awarded Nobel Peace Prize, 1970

Whoever makes two ears of corn, or two blades of grass to grow where only one grew before, deserves better of mankind … than the whole race of politicians put together.

Jonathan Swift

Tzompantli

1508 – 1538

The Spanish Conquistadors, inured though they were to hardship and bloodshed, were nonetheless taken aback by the scale and ferocity of Aztec sacrifice. They wrote horrified accounts of sacrificial rituals, and of tzompantli, the racks where thousands of skulls of sacrificial victims were displayed in front of the twin pyramids of the Templo Mayor.

The Spanish invaders tore down the Templo Mayor and paved over the tzompantli. But archeologists in 2015, excavating under old buildings in Mexico City, uncovered the tzompantli (originally built from 1486-1502) again. Here’s a recent account.

The Aztecs are not the only folk to practice human sacrifice. It’s common, especially in the early stages of setting up chiefdoms and states, where it helps to keep commoners and conquered folk properly terrorized. But the scale of sacrifice on the part of the Aztecs and other Mesoamerican societies is extreme. It’s natural to wonder what in the world was going on, whether there is some deeper reason for the cult of killing, underneath the religious rationale.

Some anthropologists have suggested a materialist explanation. The peoples of the New World had few domesticated animals, a legacy in part of mass extinctions millennia earlier that eliminated a lot of potentially domesticable species. In Mesoamerica, turkeys and dogs were about it. In less densely populated areas, Indians could supplement a diet of domesticated plants with game. But in densely settled Mesoamerica, the main source of animal proteins and fat for the elite was other humans. At least so the story goes. Marvin Harris – kind of a “protein explains all human history!” guy – set out this theory in his popular book Cannibals and Kings.

This is intensely controversial. It’s not clear that eating people on this scale makes much sense from an optimal foraging point of view. But at least we can say that the predatory ethos of Aztec rulers makes a contrast with the more pastoral ethos of many Old World rulers

However there are some comparisons between New World and Old World civilizations where the New World comes off looking better. Gini coefficients* – a measure of inequality – are never going to grab the headlines the way Aztec heart sacrifice does. But the figure below shows something interesting.

Figure 3a shows how Gini coefficients change over time in a sample of societies in Eurasia (blue) and North America / Mesoamerica (red), using house size as a measure of wealth. In both cases, the origin of agriculture and the rise of states is associated with increasing inequality. Figure 3b shows the same data, but recalibrated, so that the 0 point on the time scale is set at the origin of agriculture (which happened at different times in different places). The second figure shows a contrast between continents: a further increase in wealth inequality in Eurasia about 5000 years after the origin of agriculture (around 3000 BCE) and on into the Bronze Age, but a steady level of inequality in North America / Mesoamerica. The authors of this study suggest that the greater availability of domesticated animals in Eurasia increased the potential for wealth inequality via “agricultural extensification”, as well as via mounted warrior elites capable of creating (or stimulating the creation of) very large empires.

Result: There is no Templo Major in Eurasia. And there is no Attila or Genghis Khan in North America / Mesoamerica.

* Technical note: Where wealth is distributed perfectly evenly, the Gini coefficient is 0. Where one person owns everything and the other n-1 own nothing, the Gini coefficient is 1 – 1/n.

A cycle of Cathay

1108 – 1158 CE

The innovations which make their appearance in East Asia round about the year 1000 … form such a coherent and extensive whole that we have to yield to the evidence: at this period, the Chinese world experienced a real transformation. … The analogies [with the European Renaissance] are numerous – the return to the classical tradition, the diffusion of knowledge, the upsurge of science and technology (printing, explosives, advance in seafaring techniques, the clock with escapement …), a new philosophy, and a new view of the world. … There is not a single sector of political, social or economic life in the eleventh to thirteenth centuries which does not show evidence of radical changes in comparison with earlier ages. It is not simply a matter of a change of scale (increase in population, general expansion of production, development of internal and external trade) but of a change of character. Political habits, society, the relations between town and country, and economic patterns are quite different from what they had been. … A new world had been born.

Jacques Gernet. A History of Chinese Civilization, pp. 298-300

Scholars contemplating the sweeping economic, social, and political transformation of China under the Song dynasty (960-1279) seem compelled to draw analogies with later dramatic occurrences in Europe – with the Renaissance (as in the quote above) or with the Economic Revolution in England on the eve of the Industrial Revolution.

The changes are dramatic. Population roughly doubles, from about 50 million to about 100 million. Cities grow. Both internal and external trade boom. The division of labor advances, with different households and different parts of the country specializing in “goods such as rice, wheat, lighting oil, candles, dyes, oranges, litchi nuts, vegetables, sugar and sugarcane, lumber, cattle, fish, sheep, paper, lacquer, textiles and iron.” In a number of fields of technology – iron production, shipbuilding – China reaches heights which the West will not attain for many centuries.

With changes in the economy come changes in the relation between society and state. Taxes come to be mostly collected in cash rather than kind. Eventually revenues from taxes on commerce, including excise taxes and state monopolies, will greatly exceed those from land tax. A Council of State will put constitutional checks on the power of the emperor.

Yet Imperial China will ultimately follow a different, less dramatic developmental pathway than Europe. Some reasons why:

Missing Greek science and math. The Greeks figured out the shape of the Earth (it’s a sphere) by the fourth century BCE, and Eratosthenes produced a fairly good estimate of its circumference in the third century BCE. The news spread: educated Muslims and Christians in the Middle Ages knew the earth was round. Remarkably, however, China didn’t get the message, or didn’t pay it much attention. The standard cosmological model in China was a round heavens above a flat, square Earth, until Jesuits in the seventeenth century convinced the literati otherwise. And, while China had a sophisticated mathematical tradition (including an ingenious method of solving systems of linear equations with rods on a counting board, equivalent to Gaussian elimination), the massive mathematical legacy of the Greeks didn’t get that far. In his recent history of Greek mathematics, Reviel Netz argues that this alone is enough to explain the “Needham question” of why China did not produce a scientific revolution.

Church, state, and kin. Europe and China arrived at very different bargains between an imported ascetic otherworldly religious tradition, an imperial state, and patrilineal kin groups.

“Without the towering synthesis of the Principia there would have been no Newtonianism to define the eighteenth and nineteenth centuries, arguably no Enlightenment, and a very different trajectory to modern history. But, working backward, without Galileo and Kepler, there would have been no Principia, and … both Kepler and Galileo would have been strictly impossible without conic sections. … Kepler and Galileo, and their entire generation turned to conic sections because they had Archimedes. … Conic sections … emerged exactly once in history – as the parting shot of the generation of Archytas and as the central theme of the generation of Archimedes. Take away these two generations and you take away the tools with which to make a Newton. … Europe, rather than China or India, produced the scientific revolution because, unlike the other major civilizations, Europe had the resources of Greek mathematics”

A New History of Greek Mathematics pp. 497 et. seq.

The nomad brake. By 1000, Western Europe has largely tamed its barbarians, folding them into a settled, stratified, Christian society. But the civilized folk bordering the Eurasian steppe, in Eastern Europe and continental Asia, are in for a rougher ride. During the whole Song period, China faces a threat from nomads to the north. In the Northern Song period (960-1126), the Khitan empire, founded by steppe nomads, occupies Mongolia, Manchuria, and part of northern China. In the Southern Song period (1127-1279), the Song lose all of northern China to a new barbarian dynasty, the Jin. Finally, the Song dynasty ends when all of China is conquered by the Mongols under Genghis Khan and his heirs, with the loss of about a third of the population. For all the wealth and sophistication of the Song, the succeeding native Chinese dynasty, the Ming, does not regard them as a model to be emulated.

Rice economics. Rice is the main food crop in southern China, the most populous and developed part of the country. Here’s a basic fact about rice versus wheat production (hat-tip pseudoerasmus): diminishing marginal returns to labor are less pronounced with rice than wheat. In other words, with rice, you can produce a lot more if you’re willing to put in a lot more work. With wheat, you more quickly reach a point where additional labor yields little additional production. This simple fact has far-reaching implications. Imagine an economy with two sectors, agriculture and manufacturing. And imagine that population expands up to a Malthusian limit. Under these assumptions, and given standard economic reasoning, it makes a big difference whether the principal crop is rice or wheat. With rice (diminishing marginal returns less pronounced), equilibrium population density is greater, output per capita is less, and more of the labor force is in agriculture, less in manufacturing.

So an economic model incorporating information about labor productivity of rice and wheat seems to account for some basic differences between China and the West. But rice cultivation may have more subtle implications.

Rice psychology. An older generation of humanist scholars was willing to generalize about Chinese thinking.

It is quite clear to all those who have been in contact with this world that it is quite different from the one in which we ourselves have been moulded. … China does not know the transcendent truths, the idea of good in itself, the notion of property in the strict sense of the term. She does not like the exclusion of opposition, the idea of the absolute, the positive distinction of mind and matter; she prefers the notions of complementarity, or circulation, influx, action at a distance, of a model, and the idea of order as an organic totality. … Chinese thought does not proceed from an analysis of language. It is based on the handling of signs with opposing and complementary values.

Gernet p. 29

Within the social sciences, sweeping pronouncements like this are suspect. To hard-headed materialists and quants they look hopelessly impressionistic and unscientific. To post-colonialist critical theorists, they reek of old-fashioned, condescending Orientalism. But there is now a substantial body of research demonstrating real differences in cognitive style across cultures, and between the West and China (and other East Asian societies), in line with the quotation above.

Of note here: there is also regional variation within China. Rice paddy farming requires high levels of cooperation, including joint work keeping up irrigation systems, and reciprocal labor exchanges. And research shows that there are differences in psychology as well between wheat and rice growing regions in China. Chinese from rice growing regions are more inclined to holistic, context dependent thinking. Chinese from wheat growing regions have a more independent, individualizing cognitive style. In other words, the expansion of rice cultivation in China may have reinforced some of its characteristic cognitive inclinations.

In conclusion: the history of the Song period poses in particularly clear form the “Needham puzzle” of why the Industrial Revolution did not originate in China. The answer, it seems, is complicated, combining (at least) political and social responses to external threat, the nature of agricultural economies, and more intangible (but still measurable) differences in intellectual traditions and cognitive style.

First farmers

8.80 – 8.33 thousand years ago

Farming is now spreading out of the Fertile Crescent. Farmers have crossed the Aegean, and appear in the Balkans and Greece. (They got to Cyprus more than a thousand years earlier.) Farmers have also begun spreading out of the Yellow River and Yangzi River valleys in China.

There’s an argument among philosophers of a utilitarian bent, started by Derek Parfit, over which is better: a world with just a few very happy people (more happiness per capita), or a world crowded with a multitude of people for whom life is just barely worth living (more total happiness)? The choice of the latter has been dubbed the “Repugnant Conclusion.” Whatever the philosophical merits of one possible world or another, there’s little doubt about which direction social evolution usually takes. “God favors the side with the largest battalions” (a saying often attributed to Napoleon, but actually predating him), and agricultural populations have mostly managed to replace hunter-gatherers, even though they are probably worse fed and sicker on average. The DNA evidence shows that in Europe it’s mostly replacement we’re talking about, not just the spread of new technologies. Migrants originally from Anatolia pushed aside indigenous hunter-gatherers without much interbreeding. In Western Europe the replacement wasn’t entirely peaceful. In the north, in what is now Germany and the Low Countries, farmers from the intrusive Linear Pottery (LBK) culture built fortified settlements, and there was an unpopulated no-man’s land between farmer and hunter-gatherer territory. Along the Mediterranean shore, farmers from the intruding Cardial (Impressed Ware) culture sometimes killed foragers, and kept their heads as trophies.

For a while, a decade ago, it looked as if the spread of agriculture might also explain much of the distribution the world’s major language families. Peter Bellwood’s book First Farmers made this case. According to this theory, the first farmers in Europe were speakers of an early Indo-European language that eventually gave rise to most of the languages of Europe, as well as Iran and northern India. We’ll see in days to come on Logarithmic History that the story turns out to be more complicated.

Roots and grains, clans and kings

9.31 – 8.81 thousand years ago

Agriculture got started in the Near East by 10,000 years ago, yesterday on Logarithmic History. But a very different agricultural system may have begun around today’s date on the margins of Kuk Swamp in the highlands of New Guinea. This early date is controversial, but agriculture was clearly in place by around 6.5 kya.

The folks at Kuk Swamp were harvesting (and at some point cultivating) root and tree products: taro, yams, and bananas. We know relatively little about the early history of such crops, and their New World counterparts like manioc and sweet potatoes, since they don’t preserve as well archaeologically as grains like wheat, rice, and corn/maize.

And there may be a more consequential difference between roots and tubers, and grains. Many root crops don’t keep well once they’re harvested. Better to leave them in the ground and harvest small amounts as needed. But grains have to be harvested all at once, and then stored. There may be a further socio-political implication to this: in the case of grains, concentrated stores make it easier for tax collectors to step in and appropriate a part of the product. Around the world, grain agriculture eventually ends up associated with complex stratified societies, with elites supported by rents and taxes extracted from a dependent peasantry. Places where root and tree crops were the basis of subsistence were less likely to develop political organization beyond the local level. Highland New Guinea winds up illustrating this, with productive agriculture and dense populations, but tribal-scale politics right up to the mid twentieth century.

The Andes, where the potato was first cultivated, and a succession of empires eventually flourished, may be the exception that proves the rule. At high altitudes, potatoes could be preserved by freeze drying.

James Scott, a political scientist with some anarchist sympathies, has a recent book out, Against the Grain: Deep History of the Earliest States, about the relationship between grains and the state formation. And in an earlier book, The Art of Not Being Governed: An Anarchist History of Upland Southeast Asia, he argues that stateless folk in Southeast Asia sometimes opted for root crops for political reasons – to preserve their independence – as much as ecological ones.

Domesticated, I tell you

Agriculture on this planet is about 50 million years old, if you count ants and their underground fungus gardens. But human agriculture seems to begin about 10.5 thousand years ago, in the Fertile Crescent in the Near East, with the domestication, in a short space of time, of barley, two varieties of wheat, sheep, goats, pigs, and cattle. (The domestication of dogs came earlier, maybe a lot earlier.)

Agriculture is one of the greatest changes ever in the human condition, but whether it was a net improvement for the average person is questionable. There’s a lot of evidence that people were worse fed, and sicker, in a lot of places once they started farming. On the other hand, agriculture supports more people per acre than hunting and gathering, usually by several orders of magnitude, so population pressure is probably a big motive for experimenting with planting seeds.

But we are still left with an unsolved question. Why, after tens of thousands of years in which human beings showed little inclination to adopt farming, does it develop independently within a five thousand year span in half a dozen spots around the globe? I’ve run into anthropologists who think that it just took that long for populations to reach carrying capacity, but this shows no appreciation at all for the time scale of exponential population expansion. Any human population with room to grow can increase its numbers tens- or hundreds-fold on a time scale of less than a thousand years. So something other than population-below-carrying-capacity must have kept people from taking up farming for a long, long time. Two possibilities

1) The Ice Age climate wasn’t suited for farming. This explanation was proposed by Robert Boyd, Peter Richerson, and Robert Bettinger. We’ve already seen that Boyd and Richerson argued that the extreme climate swings of past glacial periods favored adaptation via cultural learning (rather than via individual learning or natural selection). These same swings ­– like the dramatic return to glacial condition in the Younger Dryas Cold Event – might have been too much to allow for prolonged settled life in one place, and attendant experiments with agriculture.

Another version of the argument: here’s a recent article, The ant and the grasshopper, presenting evidence that seasonality was the key factor in the the invention and adoption of agriculture. In seasonal environments, there was an incentive to store food to even out annual variations. This encouraged people to settle down, and then to start sowing plants and herding animals. The seasonality factor may explain not only when agriculture happened, but also where.

2) People weren’t genetically adapted to settled life. For example, living a settled life generally means more exposure to disease. It could have taken a long time for humans to evolve resistance to diseases of sedentism. Another possibility: natural selection might have affected behavior over this time. There’s an argument to be made that human beings are a self-domesticated species – that we have selected ourselves, as we have selected other animals, to be tamer, and less aggressive. This agreement is laid out in Richard Wrangham’s recent book, The Goodness Paradox, and I considered it in a blog post of the same title. Wrangham is mainly concerned with the transition to Homo sapiens, but some of the same morphological changes occur in the transition from early to later Homo sapiens over the past several tens of thousands of years. It may only be in the last ten thousand years or so that many human populations grew tame enough to live in settled communities and take up agriculture. In both ants and humans, behavioral evolution toward increasing cooperation within the species may have been a precursor to the domestication of other species.

No-knead bread

The Younger Dryas Cold Event, last hurrah of the last glaciation, is over. In the Near East, people are once again settling down in villages, harvesting wild grain, and hunting. leading to the first generally recognized human domestication of plants – wheat and barley specifically. So to commemorate, here’s a recipe – one of the most popular ever from the New York Times – for no-knead bread that you can make overnight (although early farmers may have favored porridge and flatbread.)

Jared Diamond took a dour view of agriculture, calling it the “worst mistake in the history of the human race.” And fans of the paleo diet claim that you should try to eat like our ancestors did before the invention of farming. But there are counterarguments: Many hunter-gatherers ate more starch and sugar (in the form of honey) than paleo proponents assume. Also, human populations (at least populations of farmers) have evolved since the beginning of agriculture; many of us are no longer quite genetically adapted to a hunter-gatherer diet. Finally, feeding most of the planet on a meat-heavy paleo diet may be impossible.

In any case, studies from the They Institute (“They did this one study …”) show that bread won’t make you fat if you only eat bread you bake yourself. So indulge.

No-knead bread

Ingredients

• 3 cups all-purpose or bread flour, more for dusting
• ¼ teaspoon instant yeast
• 1 ¼ teaspoons salt
• Cornmeal or wheat bran as needed

Preparation

1. In a large bowl combine flour, yeast and salt. Add 1 5/8 cups water, and stir until blended; dough will be shaggy and sticky. Cover bowl with plastic wrap. Let dough rest at least 12 hours, preferably about 18, at warm room temperature, about 70 degrees.
2. Dough is ready when its surface is dotted with bubbles. Lightly flour a work surface and place dough on it; sprinkle it with a little more flour and fold it over on itself once or twice. Cover loosely with plastic wrap and let rest about 15 minutes.
3. Using just enough flour to keep dough from sticking to work surface or to your fingers, gently and quickly shape dough into a ball. Generously coat a cotton towel (not terry cloth) with flour, wheat bran or cornmeal; put dough seam side down on towel and dust with more flour, bran or cornmeal. Cover with another cotton towel and let rise for about 2 hours. When it is ready, dough will be more than double in size and will not readily spring back when poked with a finger.
4. At least a half-hour before dough is ready, heat oven to 450 degrees. Put a 6- to 8-quart heavy covered pot (cast iron, enamel, Pyrex or ceramic) in oven as it heats. When dough is ready, carefully remove pot from oven. Slide your hand under towel and turn dough over into pot, seam side up; it may look like a mess, but that is O.K. Shake pan once or twice if dough is unevenly distributed; it will straighten out as it bakes. Cover with lid and bake 30 minutes, then remove lid and bake another 15 to 30 minutes, until loaf is beautifully browned. Cool on a rack.

Life goes nuclear

2.16 – 2.06 Gya

We’re now doing history at the rate of 100 million years a day.

Eukaryotic cells (Domain Eucaryota, which includes multicellular life, like plants, animals, and fungi) are, on average, much larger and more complex than the earlier evolved prokaryote cells (Domains Bacteria and Archaea*). They have organelles, including mitochondria that power them and chloroplasts (at least among plants) that carry out photosynthesis. Their DNA is stored in a nucleus, and consists not just of genes (as in prokaryotes), but of large stretches of non-coding DNA (most of their genome), separating pieces of genes. The ancestor of present-day eukaryotes reproduced sexually, although some eukaryotes have since given up sex.

There are different ways that life increases in complexity. The origin of the Eucarya has something in common with a much later event, the origin of agriculture (check out September 11 on logarithmichistory). Starting 10,000 years ago, we Homo sapiens brought other animals and plants under our control, managing their reproduction, and selecting them (first unintentionally, then intentionally) to suit our purposes, until now most domesticated creatures couldn’t survive in the wild. Our own numbers and social scale increased enormously with the rise of agriculture.

At least 2 billion years ago, an archaeon cell gobbled up one or more bacterial cells (or was parasitized by them). The bacteria ended up surviving inside it, and after many generations became a kind of domesticate inside their host. Eukaryotes do domestication one better than humans: they carry their livestock inside their bodies. Eventually this domesticate evolved into mitochondria, the little power packs that pump out ATP for the rest of the cell to use as as an energy source. Over the course of time all but a small fraction of the original bacterial genome was moved into the nucleus.

In the last few years we have come closer to understanding how this momentous step occurred: we have discovered a new branch of the Archaean tree, the Asgard archaea. The Asgard archaeans carry some genes otherwise found only in eukaryotes, and it looks likely the first eukaryote to start hosting the bacterial ancestors of mitochondria was either an Asgarder, or close branch. Just recently we finally succeeded in cultivating these creatures in the lab. (It was hard to do.) They are tiny little spheres with long filaments protruding from them. The partnership between Archaeans and bacteria may have begun with bacteria nestling in these protrusions.

Humans developed agriculture multiple times independently around the world. As far as we know, eukaryotes evolved only once, long after the origin of simpler forms. The evolution of eukaryotes might be a very unlikely chance event. The observable universe may be full of bacteria, but harbor more complex cells only sparsely.

* Domain Archaea, a billions-of-years-old group of single-celled organisms looking like bacteria but biochemically different, should not be confused with the Archaean Eon, a billions-of-years-long stretch of Earth history.

A cycle of Cathay

1053 – 1106 CE

The innovations which make their appearance in East Asia round about the year 1000 … form such a coherent and extensive whole that we have to yield to the evidence: at this period, the Chinese world experienced a real transformation. … The analogies [with the European Renaissance] are numerous – the return to the classical tradition, the diffusion of knowledge, the upsurge of science and technology (printing, explosives, advance in seafaring techniques, the clock with escapement …), a new philosophy, and a new view of the world. … There is not a single sector of political, social or economic life in the eleventh to thirteenth centuries which does not show evidence of radical changes in comparison with earlier ages. It is not simply a matter of a change of scale (increase in population, general expansion of production, development of internal and external trade) but of a change of character. Political habits, society, the relations between town and country, and economic patterns are quite different from what they had been. … A new world had been born.

Jacques Gernet. A History of Chinese Civilization, pp. 298-300

Scholars contemplating the sweeping economic, social, and political transformation of China under the Song dynasty (960-1279) seem compelled to draw analogies with later dramatic occurrences in Europe – with the Renaissance (as in the quote above) or with the Economic Revolution in England on the eve of the Industrial Revolution.

The changes are dramatic. Population roughly doubles, from about 50 million to about 100 million. Cities grow. Both internal and external trade boom. The division of labor advances, with different households and different parts of the country specializing in “goods such as rice, wheat, lighting oil, candles, dyes, oranges, litchi nuts, vegetables, sugar and sugarcane, lumber, cattle, fish, sheep, paper, lacquer, textiles and iron.” In a number of fields of technology – iron production, shipbuilding – China reaches heights which the West will not attain for many centuries.

With changes in the economy come changes in the relation between society and state. Taxes come to be mostly collected in cash rather than kind, Eventually revenues from taxes on commerce, including excise taxes and state monopolies, will greatly exceed those from land tax. A Council of State will put constitutional checks on the power of the emperor.

Yet Imperial China will ultimately follow a different, less dramatic developmental pathway than Europe. Some reasons why:

Church, state, and kin. Europe and China arrived at very different bargains between an imported ascetic otherworldly religious tradition, an imperial state, and patrilineal kin groups.

The nomad brake. By 1000, Western Europe has largely tamed its barbarians, folding them into a settled, stratified, Christian society. But the civilized folk bordering the Eurasian steppe, in Eastern Europe and continental Asia, are in for a rougher ride. During the whole Song period, China faces a threat from nomads to the north. In the Northern Song period (960-1126), the Khitan empire, founded by steppe nomads, occupies Mongolia, Manchuria, and part of northern China. In the Southern Song period (1127-1279), the Song lose all of northern China to a new barbarian dynasty, the Jin. Finally, the Song dynasty ends when all of China is conquered by the Mongols under Genghis Khan and his heirs, with the loss of about a third of the population. For all the wealth and sophistication of the Song, the succeeding native Chinese dynasty, the Ming, does not regard them as a model to be emulated.

Rice economics. Rice is the main food crop in southern China, the most populous and developed part of the country. Here’s a basic fact about rice versus wheat production (hat-tip pseudoerasmus): diminishing marginal returns to labor are less pronounced with rice than wheat. In other words, with rice, you can produce a lot more if you’re willing to put in a lot more work. With wheat, you more quickly reach a point where additional labor yields little additional production. This simple fact has far-reaching implications. Imagine an economy with two sectors, agriculture and manufacturing. And imagine that population expands up to a Malthusian limit. Under these assumptions, and given standard economic reasoning, it makes a big difference whether the principal crop is rice or wheat. With rice (diminishing marginal returns less pronounced), equilibrium population density is greater, output per capita is less, and more of the labor force is in agriculture, less in manufacturing.

So an economic model incorporating information about labor productivity of rice and wheat seems to account for some basic differences between China and the West. But rice cultivation may have more subtle implications.

Rice psychology. An older generation of humanist scholars was willing to generalize about Chinese thinking.

It is quite clear to all those who have been in contact with this world that it is quite different from the one in which we ourselves have been moulded. … China does not know the transcendent truths, the idea of good in itself, the notion of property in the strict sense of the term. She does not like the exclusion of opposition, the idea of the absolute, the positive distinction of mind and matter; she prefers the notions of complementarity, or circulation, influx, action at a distance, of a model, and the idea of order as an organic totality. … Chinese thought does not proceed from an analysis of language. It is based on the handling of signs with opposing and complementary values.

Gernet p. 29

Within the social sciences, sweeping pronouncements like this are suspect. To hard-headed materialists and quants they look hopelessly impressionistic and unscientific. To post-colonialist critical theorists, they reek of old-fashioned, condescending Orientalism. But there is now a substantial body of research demonstrating real differences in cognitive style across cultures, and between the West and China (and other East Asian societies), in line with the quotation above.

Of note here: there is also regional variation within China. Rice paddy farming requires high levels of cooperation, including joint work keeping up irrigation systems, and reciprocal labor exchanges. And research shows that there are differences in psychology as well between wheat and rice growing regions in China. Chinese from rice growing regions are more inclined to holistic, context dependent thinking. Chinese from wheat growing regions have a more independent, individualizing cognitive style. In other words, the expansion of rice cultivation in China may have reinforced some of its characteristic cognitive inclinations.

In conclusion: the history of the Song period poses in particularly clear form the “Needham puzzle” of why the Industrial Revolution did not originate in China. The answer, it seems, is complicated, combining (at least) political and social responses to external threat, the nature of agricultural economies, and more intangible (but still measurable) differences in cognitive style.