Population Theory:

HIST 3797: Population Theory
Malthus, Marx, and
Mercantilist theory (17th, 18th c):
• Population growth a good thing
• Social good measured by the wealth and power
of the nation state
• Population the source of public revenues, larger
GNP, military might, peopling colonies
• “A numerous and increasing population was the
most important symptom of wealth; it was the
chief cause of wealth; it was wealth itself—the
greatest asset for any nation to have.”
Thomas Malthus, Essay on
Population (1798)
• Social good measured by the well-being of
the people, including the laboring
• Poverty was the natural consequence of
population growth
• Malthus’s “law” of population: population
grows geometrically; food and resources
grow arithmetically
Malthusian model:
• Food is the primary resource; food scarcity
increases mortality, reduces population
• Law of diminishing returns: cultivating new land,
or more intensely, adds smaller increment to
production for each unit of labor/land
• Productivity gains from innovation cancelled out
by more pop growth
• As population increases, food prices rise
(excess demand), wages fall (excess supply),
mortality increases
Two types of checks to population
• Positive checks– anything that increases
mortality (war, disease, famine, poor living
standards) and kills off excess population
• Preventive checks- abstinence, delayed
marriage and non-marriage (“moral restraint”)
that limit the number of children born
• Preventive checks superior (less human misery)
but probably unattainable (due to human
• What’s missing?
Malthus’s theory reflects his times
• End of 18th c: population was increasing, wages
were falling
• Assumes primarily agricultural society with
limited technological innovation (at the cusp of
the Industrial Revolution), where laborers spent
most income on food (bread)
• Fertility levels depended on marriage age and
frequency; fertility control within marriage not
generally “within the calculus of conscious
Malthus’s theory became standard
argument against social reform
• Anything that raises the income of the poor (e.g.,
poor law payments) would raise the birth rate
• Number of the poor would then increase until
there were so many that incomes would fall and
mortality would increase
• Hence, it’s impossible to raise the income of the
poor; don’t try
• This argument was very popular with the rich
Malthus’s contribution to population
theory generally
• Lays out system of population and economic
dynamics (fertility vs. mortality, individual wellbeing and the broader economy)
• Sets forth premise that rising population reduces
living standards, due to diminishing returns
• Pessimistic about science and innovation solving
problems from increasing population
• Neo-Malthusians: Adopt Malthus’s pessimistic
perspective about “overpopulation,” see birth
control as preventive check
Marxist Theory (mid-19th century,
Karl Marx and Friedrich Engels)
• Criticized Malthus
• “Every stage of development” (economic
system) has its own law of population
• Pressure of population is against “the means of
employment,” not the means of subsistence
• “It is capitalist accumulation itself that produces .
. . A relatively redundant population of labourers”
• An over-simplified example
Marxist population theory, cont.
• Assumes different law of population under socialism;
centralizing the mean of production for the general good
does away with “surplus population” and poverty
• After English Industrial Revolution, so more optimistic
about “science, the progress of which is just as limitless
and at least as rapid as that of population”
• In practice, later, Communist regimes saw population
planning (like economic planning) an appropriate task for
the State (e.g., China, Romania)
• Marx’s general contribution: Distribution of resources
among the population matters, not just total population
and production levels
Boserup, et. al: Population pressure
spurs technological change
• Optimistic perspective: “Demographic growth
stimulates human ingenuity so as to cancel and
reverse the disadvantages imposed by limited
resources. A larger population generates
economies of scale and more product and
surplus, and these in turn support technological
Boserup’s argument (1981):
Population growth has stimulated technological progress.
Early in human history, growing needs of numbers of people promoted
the use of fire, the domestication of animals, the storage of food and
the development of agriculture, a productive system supporting
much larger populations than hunting and gathering.
In the following millennia, population growth stimulated improvements
in agricultural productivity, via both technical innovations and
reorganization of societies.
More recently, population growth provided the concentrations of labor
and the supply of ingenuity to spur the industrial revolution and the
development of modern societies, with their high levels of
employment in the production of services.
Some work of this type reverses
traditional causal reasoning:
Traditional economic argument:
Development of new
technology allows population
to increase.
Newly-invented technology is selfevidently superior.
Once adopted, this superior
technology supports a larger
Causality: Invention-> pop
New argument:
Wide range of possible
technological solutions.
Increased population pressure
encourages adoption of more
labor-intensive techniques.
Decreased population pressure
encourages adoption of less
labor-intensive techniques.
Causality: Pop change->
Technological change.
Example: Agricultural systems
• Low yield, low labor intensity: Slash and burn agriculture:
Trees cut and burned; ash fertilizes the soil; pointed stick
used for planting; land cultivated for 1-2 years, left fallow
for 20 years. Productivity per hour worked is high, but
only feeds small pop. w/in fixed area.
• High yield, high labor intensity: Land cleared, plowed,
fertilized, weeded, irrigated; livestock maintained; annual
cultivation, with crop rotation. Productivity per hour
worked is low, more hours worked, but feeds a larger
pop. w/in fixed area.
• System adopted depends on population pressure, may
revert back to less labor intensive (Europe after Black
Example: From hunting and
gathering to cultivation (Cohen)
• Agriculture consists of practices and techniques
known to hunter-gatherers, but usually not
practiced because unnecessary
• Hunting and gathering supplies more varied,
possibly more nutritious diet, with few hours of
• Agricultural techniques adopted due to
population pressure; more monotonous, possibly
less nutritious diet, with longer work hours—but
feeds more people in a given area (10-100 times
more people per acre)
Positive Feedback Cycle
• Gradual rise in numbers impelled people
to obtain more food, through agriculture
• Food producers generally sedentary rather
than nomadic. Sedentary life supported
shorter birth intervals, reduced “cost” of
children, leading to more pop growth.
• Note: Hunting and gathering co-existed
with cultivation in many societies.
Livi-Bacci: 3 historical responses to
population pressure
• The occupation of uninhabited or sparsely
populated regions
• Land transformation and reclamation (e.g.,
draining of swamps for cultivation)
• External expansion: emigration and
Advantages of larger population
• Encourages division of labor, leading to
more efficient production of goods
• Allows economies of scale, development
of infrastructure (e.g., irrigation systems,
transportation networks)
• Supports the growth of cities, more
complex societies
• More people =s more potential inventors of
new technology (Simon)
Current Population Theorists:
Optimists and Pessimists
• Optimists: Some economists assume that technological
innovations will solve current and future problems from
pop growth (e.g., development of substitutes for scarce
resources, broader use of contraception)
• Pessimists: Many ecologists argue that growing
population threatens resources that can’t be replaced
(e.g., climate change)
• Some predict future difficulty in increasing food
production; 1/7th of world population suffers from hunger
and malnutrition (U.N. estimate)
• Some solutions available to historical populations not
feasible today