“Subsistence” in Malthusian theory is a term of art, Brad DeLong explains:
It can mean populations under such intense nutritional stress that women stop ovulating and children’s immune systems are so compromised that they drop like flies when bronchitis hits. But it does not have to. What it does mean is that the standard of living and social institutions are such that the average woman has two children or a hair more that survive to reproduce, and that as a result average rates of population growth are glacial.
Now average rates of population growth were glacial. We expect a pre-artificial birth control human population that is nutritionally-unstressed to roughly double every twenty-five year generation: that appears to happen wherever and whenever farmers newly colonize an area with abundant land previously inhabited by hunter-gatherers. Yet, as best as we can judge, between 8000 BC and 1000 BC the average worldwide rate of population growth was roughly 0.05%/year — 1.3%/generation. From 1000 BC to 1 it was roughly 0.1%/year — 2.5%/generation. And From 1 to 1500 it was back down to 0.5%/year — again, 1.3%/generation. Either these populations were often near and frequently over the edge of women too skinny to ovulate and children so malnourished that their immune systems were badly compromised, or powerful sociological factors were driving a wedge between how rapidly the population could, biologically, reproduce and grow, and how rapidly it did go.
As Lemin puts it, four sociological factors can drive a wedge between the post-pillage or organized extortion (by thugs-with-spears and thugs-with-scrolls) living standards of the bulk of the population and bare biological subsistence:
These four are:
- female infanticide,
- prolonged female virginity,
- substantial female celibacy, and
- a large artisan class devoted to making goods and providing services to make life comfortable and even luxurious — but making goods and providing services that do not directly enhance reproductive fitness.
Thus Greek and Roman-like female infanticide — even of girls born to full-citizen wives. Greek and Roman-like large-scale slavery: unlike the post-1807 slave population in the U.S. South, Greek and Roman slave populations did not reproduce in sufficient numbers to sustain their levels via natural increase. Western-European marriage patterns — as her father, I say you cannot marry my daughter and take her out of my house until you have inherited or established a farm of your own. Chinese lineage households — as your elder brother, I say you cannot bring a wife into this household until we get more resources. And there are other, less patriarchal ways: Phoenician and Greek Mediterranean trading networks allowing for greater variety of diet and cross-regional pooling of scarce non-food resources like tin, amber, spices, wood, and so on without substantially impacting reproductive fitness. Imperial Roman artisan productivity taking advantage of economies of scale and distribution. All of these keep “subsistence” in Malthusian theory from exactly meaning “subsistence” on the ground.
They aren’t the greatest thing since sliced bread. But it is not a society of eight average pregnancies leading to five live births, three children surviving to age five, of whom two grow up to reproduce. It is a society of six average pregnancies leading to four live births, of whom two grow up to reproduce. Most of these “preventative check” mechanisms exert draconian control over female sexuality, freedom, and autonomy. But they allow a population in balance with resources and material comfort much higher than that of the “positive check”.
“unlike the post-1807 slave population in the U.S. South, Greek and Roman slave populations did not reproduce in sufficient numbers to sustain their levels via natural increase.”
Nowhere else in the Western Hemisphere for that matter, other than that part of British North America that became the United States.
Slaves in the American South — other than slaves working in sugarcane or rice plantations — probably experienced a higher effective standard of living than most Europeans in the same time period. They might well have been “taxed” less ,too — where in this case one defines “tax” as the fraction of their economic output not used to support the slaves themselves.