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Before I can start the actual post, I need to define some terms:
Demographic Shift: As countries modernize, the birthrate drops, and we don't know why. It's clearly tied up in women's liberation, but we don't know the direction of causality. My favorite hypothesis is that children are economic assets when farming, or even industrializating, but become extremely expensive consumption goods in modern society. Even if you expect your kid to support you post-retirement, that's a much weaker incentive then when you could use your kid to remove pests from your crops starting at age 4.
Farming was a huge step backwards for humanity: Hunter/Gatherers ate better and worked less. If you had the choice of being an isolated H/G tribe or an isolated farmer, go hunt and gather. Farmers nonetheless drove H/Gs off their land because there were more of them. Essentially, hunter/gatherers were the elves, beautiful and strong but ultimately waning in number, and farmers were the orcs: stupid an weak but present in overwhelming numbers. This is because hunter/gatherers suffered more variation is food availability, and kept* their population at a level that could be sustained at the lowest point. At any time other than the worst, they ate pretty well. Farmers had a much more consistent output, but the loss of variation meant they suffered deficiency diseases even before their population level increased to the absolute maximum capacity of their food supply. Another way of putting this is that population size is determined by the arithmetic mean of food availability but individual health is determined by the geometric mean of food consumed: this means that increasing variability decreases population but increases their health. And again, children were economic assets to farmers but dead weight to hunter/gatherers.
My current book, Farewell to Alms makes an additional point that any increase in population will decrease the standard of living, because food production has diminishing marginal returns. Once that way is exhausted (e.g. you're already feeding all the people you can on grazing animals) you have to start something with lower returns (e.g. grain cultivation).
Malthusian Trap: But wait, there's an escape from that: make everyone more productive (e.g. invent tractors). For most of human history, this failed to raise living standards, because we just bred more instead. We escaped this around 1800 (+/- 100 years, depending on who you ask), with the advent of industrialization. The questions is, how did we escape this, and reach this lovely state where things get awesomer every year, immigrants are boons to the economy, and my cats eat substantially better than most medieval farmers? Obviously the Demographic Shift helped, but that really just kicks the question up a level, plus the Demographic Shift is generally considered to have happened later.
In nature, if creatures don't exploit their food source to exhaustion, it's because they are themselves food to something else. Predation stopped being a population-level threat to us long ago, but as our productivity gains allowed us to specialize, we started to form cities. And with cities came the one predator we couldn't hit with sticks: disease.** Paradoxically, the fact that our richest form of productivity growth required us to live in disease-vulnerable conditions actually made them more useful. This means that the societies with worse hygiene (Western Europe) had higher per capita incomes than societies that thought maybe they shouldn't bathe in human waste (China and Japan).
So it appears that England lucked into disease ridden conditions long enough to allow industrialization (along with other factors), which allowed them to grow fast enough to trigger the demographic shift, at which point productivity increases continue to outpace population increases and everything becomes progressively more awesome. On average. Apparently Malawi farmers eat considerably worse than medieval English peasant farmers.
*I'm using an active verb because primitive tribes did practice a variety of forms of birth control and infanticide to keep their numbers down. But if they hadn't, starvation would have done it for them,
**Keeping poorly fed herd animals didn't help here either, but to really control the population, you needed density.
Demographic Shift: As countries modernize, the birthrate drops, and we don't know why. It's clearly tied up in women's liberation, but we don't know the direction of causality. My favorite hypothesis is that children are economic assets when farming, or even industrializating, but become extremely expensive consumption goods in modern society. Even if you expect your kid to support you post-retirement, that's a much weaker incentive then when you could use your kid to remove pests from your crops starting at age 4.
Farming was a huge step backwards for humanity: Hunter/Gatherers ate better and worked less. If you had the choice of being an isolated H/G tribe or an isolated farmer, go hunt and gather. Farmers nonetheless drove H/Gs off their land because there were more of them. Essentially, hunter/gatherers were the elves, beautiful and strong but ultimately waning in number, and farmers were the orcs: stupid an weak but present in overwhelming numbers. This is because hunter/gatherers suffered more variation is food availability, and kept* their population at a level that could be sustained at the lowest point. At any time other than the worst, they ate pretty well. Farmers had a much more consistent output, but the loss of variation meant they suffered deficiency diseases even before their population level increased to the absolute maximum capacity of their food supply. Another way of putting this is that population size is determined by the arithmetic mean of food availability but individual health is determined by the geometric mean of food consumed: this means that increasing variability decreases population but increases their health. And again, children were economic assets to farmers but dead weight to hunter/gatherers.
My current book, Farewell to Alms makes an additional point that any increase in population will decrease the standard of living, because food production has diminishing marginal returns. Once that way is exhausted (e.g. you're already feeding all the people you can on grazing animals) you have to start something with lower returns (e.g. grain cultivation).
Malthusian Trap: But wait, there's an escape from that: make everyone more productive (e.g. invent tractors). For most of human history, this failed to raise living standards, because we just bred more instead. We escaped this around 1800 (+/- 100 years, depending on who you ask), with the advent of industrialization. The questions is, how did we escape this, and reach this lovely state where things get awesomer every year, immigrants are boons to the economy, and my cats eat substantially better than most medieval farmers? Obviously the Demographic Shift helped, but that really just kicks the question up a level, plus the Demographic Shift is generally considered to have happened later.
In nature, if creatures don't exploit their food source to exhaustion, it's because they are themselves food to something else. Predation stopped being a population-level threat to us long ago, but as our productivity gains allowed us to specialize, we started to form cities. And with cities came the one predator we couldn't hit with sticks: disease.** Paradoxically, the fact that our richest form of productivity growth required us to live in disease-vulnerable conditions actually made them more useful. This means that the societies with worse hygiene (Western Europe) had higher per capita incomes than societies that thought maybe they shouldn't bathe in human waste (China and Japan).
So it appears that England lucked into disease ridden conditions long enough to allow industrialization (along with other factors), which allowed them to grow fast enough to trigger the demographic shift, at which point productivity increases continue to outpace population increases and everything becomes progressively more awesome. On average. Apparently Malawi farmers eat considerably worse than medieval English peasant farmers.
*I'm using an active verb because primitive tribes did practice a variety of forms of birth control and infanticide to keep their numbers down. But if they hadn't, starvation would have done it for them,
**Keeping poorly fed herd animals didn't help here either, but to really control the population, you needed density.
