Why has China always had so MANY people?

Those conflicts were horrible, but there were decades, even centuries between them, when China was more or less at peace under a single government. Whereas Europe has not had a central authority since the Fall of Rome, and different parts have been in almost continuous conflict since that time.

Maybe Taoism/Buddhism had a role in that whereas Europe was going through Abrahamic religions.

Yes, but China has been densely populated since the bronze age. China has had various waves of central rule and collapse of central rule. China has gone through innumerable wars, rebellions, invasions, conquests, massacres, revolutions, famines, and natural disasters. Indian history is the same way.

And what happens after the wars and destruction? The peasants go back to farming, and the productive farmland produces lots of food, and the population rebounds with the surplus, until there is no more surplus.

Europe has been poorer and less populated and technologically behind India and China and the Middle East for most of history. It’s only in the 1600s that Europe started to catch up. Lack of central government is part of it. The Roman Empire wasn’t primarily a “European” empire, it was a Mediterranean Empire. The Roman Empire was famously held together by grain imports…from Egypt and North Africa.

Wars only affect population when the peasants are killed and can’t farm anymore. And when you look at the long history of medieval European wars, we see a common pattern–the aristocrats fight limited wars, the purpose of which is to see who gets to rule and exploit the existing base of peasant farmers. The peasants are part of the prize to be won by conquering various lands, not enemies to destroy. Sure there are sometimes examples of peasants being put to the sword–but only when conquering the land isn’t an option.

China has had unified rule more often than Europe because it’s geographically more unified. Again, we’re talking China proper here. China has variously ruled various peripheral regions in various was over the millennia, but those conquests were fueled by superior armies fed by surpluses created by superior productive farms. And central China doesn’t have any particular natural geographic barriers like Europe does.

I don’t think I’m being unreasonable if I suggest that the number of inferences required to extrapolate the cause of Chinese population growth from your hairdresser’s experience puts a burden on fundamental logic fair greater than it can reasonably bear.

China has also been far more subject than Europe to invasions from steppe nomads, who (sometimes) care nothing for the life of peasants. The history of China is replete with such invasions - the primary purpose of the “Great Wall of China” was to keep 'em out (another purpose was to keep taxable peasants in … ).

Europe is reasonably lucky in this respect - it has much more varied and difficult terrain, once one is past the plains of Hungary. Sure, it suffered the occasional Huns, but such incursions were relatively rare compared with what China suffered.

Yup, a nice cold is a blue extra kick F4 glide day, but all those months spent frolicking in the snow are months when there’s nothing growing locally. Prior to industrialization, that kept the Great Lakes dinner table based on local hunting and fishing, supplemented by non-meat foraging, with limited garden plot or very small scale agriculture at the southern end of the Great Lakes, rather than relying on bulk transportation as we do today.

At the top of the Great Lakes in Canadian Shield country, it’s rock, trees and water, with only the occasional fertile valley, so even if it were not “nice cold” to “freeze your nuts off cold” for almost half the year, it still would not be a friendly land for farming.

Then you shouldn’t have used the present tense.

And we’re only talking about a difference of 1000 years in uptake, millennia ago. Wheat is an import to both regions, and in China, it just replaced millet, so it’s not like the Chinese were ever a one-grain monoculture. Point being, you’d have to look elsewhere for any China-India difference in historical high population maintenance (if such is the case, I don’t know).

I doubt polygyny was much of a factor; only the richest men indulged in it, and only the Emperor’s had large harems.

Cecil Adams weighed in on a related topic 20 years ago, and says something pretty similar, though looking at it from the opposite end:
Why did Europeans dominate the world and not vice-versa?

I call BS. No offence Lingyi but I think you’re claiming a mythical “Chinese culture or concept” where it doesn’t really exist…

The Qin Emperor controlled what is now a tiny part of the Yellow River region of China. Even core China (excluding Manchuria, Tibet, Xinjiang) is much more recent.

“the empire, long divided, must unite; long united, must divide” (话说天下大势,分久必合,合久必分). Romance of the 3 Kingdoms circa 200 AD.

It’s a freaking myth that China has 2000+ years of history. There are long periods of dynasties, decline and fall, anarchy, invasion by nomadic tribes, etc. The Tang Dynasty (618-907 AD) was rivaled by Tibet – so much so the emperor sent his daughter as a bribe. The Chinese claim the Yuan Dynasty (1279-1368) as theirs, even though it was basically a pimple on the ass of Genghis Khan’s empire. BTW, Genghis Khan and descendents spread a lot of seed (not sure the veracityof this web site per say, but let’s just say a Mongolian in the woodpile ain’t exactly front page news).

IIRC from Malcolm Gladwell’s explanation of why Chinese are good at math (!?) he mentions not only the productivity of rice paddies, but also that properly managed a farmer could get 3 crops a year from his fields.
But yes, the Great Lakes area is NOT really good agricultural land like the Chinese or India areas. For one thing, besides winters, it was covered with massive trees, someone of an impediment for the people without metal tools. Those lands that are agricultural tended to not be just off a large river for irrigation as needed. A more logical area would be the Mississippi valley, which would be analogous to the Yangtze and Ganges… and surprise, despite having only a few centuries of agriculture to build on, there was a massive civilization spread around the central valley - the mound builders built huge… mounds (!) with primitive tools, and some cities were on the order of 10,000 people. Some argue that climate change did them in, like the Viking Greenlanders; others suggest it was European diseases. Left to their own devices, there was a good chance they would over a millenia or two reach a level comparable to the Chinese.

Isn’t forest the climax vegetation in most of the Chinese river valleys? So the original agriculturalists would have contended with massive trees. A lot of work to clear, but once done, arable land is much easier to maintain.

Clearing forests without iron axes is problematic. There was copper traded (and mined in the furter east (e.g. Porte de l’Enfer just downstream of the Mattawa River’s Grand Pariseau Falls), but the closest iron implements were on the Pacific coast. Far less difficult to hunt, fish and forage.

By contrast, China had iron implements from way back.

My (Chinese) mother-in-law’s grandfather had 3 wives, and he was not a rich man. She just turned 70, so the marriages would have been around the 1910s or so.

Anyway, polygamy doen’t have any impact on birth rates.

The natives of the Great Lakes area practiced migratory slash-and-burn agriculture. So they’d burn down the area they wanted to turn into field, then plant - but exhaust the soil and have to move within a few years. (Plus, they also relied on some hunting). Maybe if they’d had another few millennia to perfect their technique they would have figured out how to stay in one place and replenish the soil - which would then lead to population expansion. But corn (maize) had only been available as a staple crop for about a millennia. They were still nomads.

Any chance that cleanliness standards would have affected things significantly?

No sure about China, but in India the Ganges picks up a lot of silt in its early life on the mountains (Himalayas). Once it makes it to the plains, it decelerates and deposits that silt. This combined with raging rivers during the monsoons, results in the river changing course (sometimes it moves a mile away from its original path). This effectively kills large trees.

How clean was the average medieval Chinese peasant?

What makes you think that Europeans were infested with lice and encrusted with shit, while Chinese and Indians were clean? Monty Python?

Subsistence farming isn’t for people who are afraid to get their hands dirty, that’s for sure. But it isn’t any easier or cleaner in Hebei than it is in Tuscany or Flanders.