POPULATION THEORY
Alberto Veira Ramos
alberto.veira@uc3m.es
(I)
ANCIENT THEORIES
POPULATION AND THE ENLIGHTMENT
THE MARXIST PERSPECTIVE
MODERN THEORIES
THE DEMOGRAPHIC TRANSITION
POPULATION STRUCTURE
(II)
CONTEMPORARY THEORIES
CURRENT CONTROVERSIES AND DEBATES
RECCOMENDED HANDBOOK
 A great deal of the
materials presented in
this course are from the
book of Professor Jesús
Javier Sánchez
Barricarte
 “El Crecimiento de la
Población Mundial”
POPULATION THEORIES
 Population control as an old matter of concern in
human societies
 Need for stimulating or controlling population
growth
 Reasons:




political
military
social
economic
ANCIENT CHINA
 Confucius (555-479 b.c.):
 All Chinese must worship the souls of ancestors by
performing certain rites which only males can do
 Under high mortality regime, ensuring the survival of at
least one male descendent to adult age requires for a family
to have several children
 There is, however, an “optimal” number of people whom
could live within a given territory
 It is the duty of the ruler to (re-) distribute population
accordingly to this principle, if necessary, colonizing new
lands
ANCIENT GREECE
 Plato (428-348 b.c.) in The laws:
 Ideal de city-state: 5.040 families
 Authorities must regulate population growth
Favoring immigration
 Favoring colonization
 Restricting number of births

 Aristotle (384-322 b.c.) in The policy:
 A great city is NOT an overcrowded city
 Too many people can cause social unrest
 Abortion and infanticide may be used if necessary
ANCIENT ROME
 Roman Civilization (509 a.c.-395 b.c.):
 Demographic growth positive for militaristic expansion
 César Augusto enacted laws promoting natalism
ANCIENT ARAB WORLD
 Ibn Jaldun (XIV century):
 High population density is a positive element
 It allows for a greater division of labor
 Demographic decline is a symptom of decadence
RELIGIONS
 All major religions hold pro-natalistic views
 Hinduism
 Judaism
 Christianism
 Islam
ANCIENT SCHOOLS OF THOUGHT
 Pro-natalist:
 Confucius  More riches for the Emperor and settlement of
new lands
 Romans  military expansionism
 Ibn Jaldun  Division of labor
 Preserve the “ideal size”:
 Preserve good governance and avoid social unrest
 Plato  Immigration or colonization
 Aristote  Abortion or infanticide
THE ENLIGHTENMENT (SUMMARY)
 Mercantilism (XVI-XVIII):
 Power and wealth of the State (the King) increases along
with production and export of manufactured goods
 More population entails more artisans and merchants
 Fisiocracy (XVIII France):
 Economic growth (and the welfare of the population) is
limited by agriculture production
 Marquis de Condorcet:
Science can favor “unlimited” growth of food production
 Families are capable of self-regulating their own reproduction

 Classic School of Economics (XVIII-XIX):
 Adam Smith, Thomas Malthus, David Ricardo y John Stuart
Mill
THE ENLIGHTENMENT
 Mercantilism (XVI - XVIII):
 Power and wealth depend on the accumulation of
money and precious metals (gold and silver)
 A growing population…
Higher division of labor (more artisans and merchants)
 More production and export of manufactures
 More revenues for the treasury
 May empoverish farmers and peasants but that has a positive
effect because makes them to work harder (Sir William Temple)

THE ENLIGHTENMENT
 Mercantilism (XVI - XVIII):
 Pronatalist
policies:
 Favor marriage and large families
 Improve public health (to reduce mortality)
 Deter emigration (except to colonies)
 Promote immigration (especially highly
qualified artisans and merchants)
THE ENLIGHTENMENT
 Mercantilism (XVI - XVIII):





Jean Baptiste Colbert (1619-1683):  No taxes to those
married aged 20 to 25 and to fathers of at least 10 children
Sir William Temple (1628-1699):  Demographic preassure is
good against lazyness
Sir William Petty (1623-1687):  The prosperity of the
Netherlands is due to its high population density
Giovanni Botero (1543-1617):  “Virtus generativa” (constant)
and “virtus nutritiva” (sets the limits but can be increased)
Luís Ortiz (XVI) y Sancho de Moncada (XVII):  Alert about
the negative consequences for Spain derived from the
colonization of the Americas
THE ENLIGHTENMENT
 Fisiocracy (XVIII):
 The true nature of wealth is not commerce but agriculture
(François Quesnay, Jacques Turgot, Benjamin Franklin)
 Only increasing agriculture production population can
increase
 Favorable to population growth providing agriculture
production can increase accordingly
 Main goal of good government is to favor agriculture
production
THE ENLIGHTENMENT
 Nicolas de Caritat, Maquis de
Condorcet (1723-1790):



Technological progress has no
limits
Science may always provide the
necessary means to increase
agriculture productivity
according to human needs
Otherwise couples would
voluntarily and smoothly would
adapt to situation by lowering
their fertility
THE ENLIGHTENMENT
 Adam Smith (1723-1790):



Demographic growth is the growth
of human productive capacity
It is the corner stone of progress
and the division of labor, a key
factor for the creation of wealth
Reproductive behavior responds to
the demand for labor:



Higher demand implies higher
salaries
Higher salaries lead to earlier
marriages and higher fertility
Children contribute to the
household wealth
At some point,
the focus of the
most notorious
intellectuals
begins to shift
From
discussing
how to
increase the
wealth of
the nation
 to how to
reduce the
number of
poor people

POVERTY IN CITIES
Slums (poverty)
Slums (overcrowded houses)
Slums (child poverty)
THE ENLIGHTENMENT (social debate)
 John Stuart Mill (1806-1873):
 Working classes may reduce their fertility to prevent salaries from
decreasing

(conflict between common good and individual self-interest)
 David Ricardo (1772-1823):
 Poverty is caused by the economic system

(rent income vs trade income)
 Thomas Malthus (1766-1834):
 Poverty is caused by the “law of diminishing returns” on
agriculture

(scarcity of food is unavoidable given limitless population growth)
Thomas R. Malthus (1766-1834)
 Priest of the Church of
England
 Professor of History and
Economy
 Son of Thomas Daniel, an
admirer of Condorcet and
Godwin (both fisiocrats) who
believed that technological
progress is limitless
Thomas R. Malthus (1766-1834)
 “An Essay on the Principle of Population” (1798)
 Refute the optimistic views of contemporary schools of
thought
 Those who trust on self-regulation of human
populations
 Those who trust on technological progress
 His thesis is based on three principles
 Food is necessary for the survival of humans
 The passion between the sexes is necessary and has
never varied in the past nor will it do in the future
 Agricultural production is subject to the “law of
diminishing returns”
Thomas R. Malthus (1766-1834)
 The Passion between the sexes
 Human populations reproduce themselves in a way
that they tend to grow exponentially (2, 4, 8, 16, 32...)
 The law of diminishing returns
 Food production increases arithmetically (1, 2, 3, 4, 5…)
 Adding more farmers to work on the fields does not
contribute to increase food production accordingly
 Malthus established his “Principle of Population”
as a natural and divine universal law:

“The power of population is so superior to the power of
the earth to produce subsistence for man, that
premature death must in some shape or other visit the
human race”
Law of diminishing returns
Law of diminishing returns
Law of diminishing returns
Malthusian trap
Thomas R. Malthus (1766-1834)
 Two forces keep human populations
beneath their limit:
 Positive
checks increase mortality:
 famines,
epidemics, pestilences, wars, natural
catastrophes, malnutrition, unemployment, low
salaries, extreme poverty, unhealthy living conditions
 Preventive
checks derived from voluntary
human action oriented to self-control
 abstinence
and delay of age at marriage (the only
morally acceptable ones for Malthus)
Thomas R. Malthus (1766-1834)
 The true cause of human misery is
 A natural universal law: The principle of population
 It is not caused by the malfunction of human institutions
which could be reformed (as Godwin, Condorcet or his
own father believed)
 Neither the Society, nor salaries, nor God are responsible
for the misery of the poor people
 The only ones to blame for their suffering are the poor
themselves, for having reproduced irresponsibly

People from working classes are not sufficiently motivated to
exercise a responsible self-control on their reproduction

Therefore, human growth is controlled mainly by wars,
diseases and famines
Thomas R. Malthus (1766-1834)
 He opposed the so
called “poor laws”
aimed at providing
relief to the poor people


Malthus believed that
unless poor people
experience all the hardships
derived from their own
reproductive decisions they
would not change their
behavior
Public charity allows for
poor people to continue
reproducing themselves
irresponsibly
Charity and the “poor laws”
Malthusianism today
 The law of diminishing returns on agriculture has
been refuted, most particularly over the last
quarter of the 20th century
The Malthusian model applies only to underdeveloped
societies, closed to technological innovation
 Amelioration of living conditions often brings increase
on the number of poor people. Why?
 Malthus failed to notice that population increase was
caused by the drop of (infant) mortality and not by the
increase of fertility among poor people

THE FALL OF MORTALITY
 Improvements in living conditions in cities
 Sanitation
Control over water supply reduced the risk of cholera
 Cleaner streets and healthier habits


Vaccination
Lady Montagu’s “variolation” against small pox
 Edward Jenner’s “vaccination” against small pox
 The Balmis expedition

 Improvements on transportation
 Steam engine on trains and ships
 Improvements on food production
 Crops from other continents
Sanitation in XVII-XVIII
Sanitation
Sanitation
Sanitation
Sanitation
Sanitation
Lady Montagu: variolation
Edward Jenner: vaccination
Cowpox and Smallpox
The Balmis expedition
Transportation
THE FALL OF MORTALITY
 Mortality differential between cities and villages
 Mortality also decreases because of social
development (not exclusively because of technical
innovations)

Tighter control of epidemic outbursts (effective enforcement of
quarantines)



The plague in Marseille
Statistical surveys on causes of death in the Ottoman Empire
Effects of wars are reduced by tighter discipline

Napoleonic army codes



burial of the death
food in can, less plundering the land
vaccination of soldiers
Malthusian trap finally avoided?
Malthusianism today
 Nowadays, however, neo-malthusians proclaim that the
unlimited growth of human population is still a threat,
because of the scarcity of natural resources
 http://www.youtube.com/watch?v=4V09jl5WIvw
Law of diminishing returns at school
THE MARXIST PERSPECTIVE
 Karl Marx (1818-1883): denied the existence of a
natural law causing poverty among working classes
 There are no “general laws”; each system of
production generates its owns
 Misery is not caused by an excessive number of
people, rather it is caused by the capitalist system of
production and private property
 The capitalist system has its own law concerning
population: “Surplus population theory”
THE MARXIST PERSPECTIVE
 Marx’s “surplus population theory”
 The worker sells the capitalist its labor and the
capitalist pays a salary that is just above the
subsistence level
 The salary represents only a fraction of the value
derived from the worker’s work
 The “surplus” is kept by the capitalist
 Capitalists seek to maximize their profits
 To keep salaries down, the capitalist system requires
large numbers of unemployed workers, the so called
“reserve army of labor”
 Introduction of machinery allows capitalists to trim
down their need for workers, making them redundant
THE MARXIST PERSPECTIVE
 There is no overpopulation in relation to production but in
relation to the number of jobs offered by the capitalists


There is enough production (food and goods) for all
There are not job for everyone, so not everyone can access to produced goods
equally. This facilitates production accumulation by the capitalist class
 According to Marx, Malthus only defended the interests of
landlords (the agricultural oligarchy) and the most
conservative fraction of the bourgeoisie
 The increase in the number of poor people was the most
eloquent consequence of the malfunctions of capitalism
 In a well organized communist society more people should
mean more wealth, not more poverty


Marx refutes the “law of diminishing returns”
Orthodox socialists consider that fertility control is a bourgeois remedy
against poverty and economic inequality (unlike Communist China nowadays)
SOCIOLOGICAL THEORIES
 Those which emphasize the goods of demographic
increase:


Émile Durkheim (1858-1917)
Eugène Gustave Dupréel (1879-1967)
 Those which argue that progress leads to decrease in
fertility


Arsène Dumont (1849-1902)
Ludwig J. Brentano (1844-1931)
SOCIOLOGICAL THEORIES
 Émile Durkheim (1858-1917):
 High population density is fundamental to stimulate progress
 It facilitates division of labor
Mechanic solidarity
 Organic solidarity



Division of labor grows at a faster pace if populations grow at a
higher rate
Industrialized societies have reached a higher division of labor
(larger list of occupations and social classes) than primitive
societies because they have a higher demographic density
SOCIOLOGICAL THEORIES
 Eugène Gustave Dupréel (1879-1967):
 Population increase is the most decisive element for
progress and modernization of a society
 Population growth stimulates competition and
individual initiative
 Higher population density entails more “contacts”
between individuals
 Population growth stimulates the development of new
techniques and “inventions” aiming to increase
production
 Absence of population growth produces economic and
technological stagnation and deters entrepreneurial and
innovative spirit
SOCIOLOGICAL THEORIES
 Arsène Dumont (1849-1902):
 There are three population principles and not just one:
 The Malthusian model  animals and primitive
societies of hunters and gathers
 The
Adam Smith model populations adjustment
responds to available employment
 The “Social Capillarity” model  couples have fewer
children if opportunities for social mobility are higher.
Fertility is higher in societies of rather rigid systems of
social stratification
SOCIOLOGICAL THEORIES
 Ludwig Joseph Brentano (1844-1931):
 The human being is a pleasure-seeking creature
 Poor people need motivation to reduce their fertility
voluntarily
 The pleasure associated to having children may be replaced or
combined with other pleasures
 Privileged classes have fewer children because they find
available a more diverse variety of sources of pleasure
Traveling, reading, esthetics, culture
 Focus more on quality rather than on quantity
 Social reproduction



Drop of fertility occurs when progress makes available new
forms of pleasure to larger numbers of people
(Uwaga!: for some industrial workers having more children
was the rational thing to do)
MATHEMATICAL THEORIES
 Exponential growth model
 Logistic curve model
 Edward Deevey logarithmic scale model
MATHEMATICAL THEORIES
 Exponential (geometric)
growth model:




Growth is limitless and
growth rate is constant over
time
Population doubles itself
faster
Population growth after the
industrial revolution seems
to fit to this type of growth
In truth such model is
adequate to make population
forecasts for one or two
decades
Population growth
Population growth
Population growth
7,000
6,000
5,000
4,000
3,000
2,000
1,000
0
MATHEMATICAL THEORIES
 Logistic curve model:
High growth rate at the
beginning
 Growth slows down
after reaching a certain
point
 Growth decelerates as
population approaches
a certain “limit”

Population growth and yearly growth rates
2.50
8,000
7,047
2.22
2.00
6,854
2.00
1.98
1.86
6,057
1.53
5,255
1.50
1.32
7,000
6,000
1.41
5,000
4,430
1.13
1.00
4,000
3,691
% anual
2,000
1,613
0.070.080.06
1,243
Población
1,000
968
2,012
2,010
2,000
1,990
1,980
1,970
1,960
0
1,850
1,800
1,750
1,700
1,600
1,500
1,400
1,340
1,300
1,250
-0.25 580 682 775
429 439 374 458
413
399
301
1,200
1,100
1,000
900
800
700
600
500
200
400
223 250 255 204 205 211 210 227 227 257
0.27
0.220.27
0.18
1,900
0.08
0.06
0.01
0.000.030.00
0.00
-0.10
1
-200
-500
-400
-1,000
-2,000
152
20 40 60 100 80 100
-3,000
6
-4,000
-10,000
-0.50
-5,000
0.10
0.050.07
0.05
0.05
0.00
-0.02
0.130.17
1,950
0.33
0.23
0.00
3,000
3,020
0.570.60
0.50
2,521
0.52
0.50
Population growth and projections
MATHEMATICAL THEORIES
 Edward Deevey (1914-1988):


Deevey used logarithmic
scales to plot human
population growth over time
Growth patterns show three
landmarks in human history:
 Paleolithic revolution
about 1 million years ago
 Neolithic revolution about
10.000 years ago
 Industrial revolution
(1750-)
MATHEMATICAL THEORIES
 Edward Deevey(1914-1988):
 Humans have always pushed upwards the carrying capacity of
our environment by developing new technologies
 Contrary to what Malthus said, human population growth is not
constant over time
 Technological and social advancements and improvements cause
an increase on demographic growth after they are implemented
but growth slows down gradually as populations reach the limit
set by those improvements and economic conditions
Edward Deevey’s model of logarithmic scale
Population growth I (Paleolithic and Neolithic)
20
18
16
8000 A.C.: Holocene
End of last glacial period
(Würm) Higher sea level
14
12
10
Human populations affected by climate changes
8
6
Paleolithic revolution
Neolithic revolution
4
2
0
-100,000
-40,000
-35,000
-30,000
-25,000
-20,000
-15,000
-10,000
-5,000
Population growth I (Rise of ancient civilizations)
Population growth II (Global trade)
1,000
900
800
700
1315-17: Little iceage. Bad crops in
Europe
600
1337: the 100 years
war
500
1348-75: The
Plague
S. X-XIII: End of the Dark Ages,
cultural renaissance in various areas
of the world
400
300
200
100
1760 A.C.: Hammurabi code
(first written laws)
Diffusion of agriculture
Apogeo y crisis de las grandes civilizaciones clásicas:
Mesopotamia, China, Egipto, India, Persia, Grecia, Roma
Age of metals: wars
0
476-1000: Dark Ages, numerous invasions
1750-1850: The
industrial
Revolution
S.XVII-XVIII: The
Enlightenment
and the Scientific
1200-1300: Mongol
invasions
950-1250: Warm climate due to
increasing solar activity
(Vikings in Greenland)
S. XV-XVI:
Transoceanic
commerce
Population growth III (Industrial revolution)
8,000
7,000
1800-2000:
Population X6 in 200 years
6,000
1950 -2012:
Population increases in 4.500 millions after decolonization
5,000
4,000
3,000
1960-2011: Population grows from 3.000 to 7.000 millions (4.000 millions in half a century)
2,000
1,000
275 millions in
50 years
908 millions in
50 years
370 millions in
50 years
0
1,800
1,850
1,900
670 millions in
10 years
500 millions in
10 years
1,950
1,960
825 millions in
10 years
740 millions in
10 years
1,970
1,980
797 millions in
10 years
802 millions in
10 years
1,990
2,000
2,010
2,012
Controversy regarding population growth
 Population growth entails social problems and may
be regarded as a problem for the future

Aristotle, Malthus, Marxists –China-
 Population growth is the engine of economic and
social development because it allows for a more
intense division of labor

Mercantilism, Adam Smith, Marx, Durkheim, Dupréel
 Population growth is a consequence of technological
and social development

Edward Deevey
Controversy regarding population growth
 Demographic growth must be limited
 Malthus, China
 Demographic growth must be stimulated
 Mercantilism, France
 Populations regulate themselves and no direct
intervention from the state is required


Adam Smith  salaries y market
Dumont y Brentano  social mobility and social reproduction
(Uwaga!: for some industrial workers having more children
was the rational thing to do)
THE DEMOGRAPHIC TRANSITION
 Adolphe Landry (1874-1956):


1909. "Les trois théories de la population." Revue Scientia.
1934. La révolution démographique. Paris: Sirey.
 Warren Thompson (1887–1973):

Thompson, W.S. (1929), "Population" American Sociological Review
34 (6): 959-975.
 Frank Notestein (1902-1983):


Notestein, F.W. (1945), "Population - The long view." in Schultz,
Theodore William -Ed-, Food for the world, Chicago, University of
Chicago Press, pp. 36-57.
Notestein, F.W. (1953), "Economic problems of population change."
Presented at Eight International Conference of Agricultural
Economists, London.
THE DEMOGRAPHIC TRANSITION
 The Demographic transition theory became popular
among politicians after the second world war,
because of the geopolitical changes that took place
following the emancipation of large areas of Africa
and Asia
 Can the European experience be a model for what
may happen in third world countries?
 The European Fertility Project at the Princeton
University

http://opr.princeton.edu/archive/pefp/
The European Fertility Project:
 The European Fertility Project at the Princeton
University (http://opr.princeton.edu/archive/pefp/)




The most ambitious research project in social sciences up to
then and the first to make use of computers
It purpose is to test the validity of the DT model
Information on 1.229 European regions was gathered from
periods ranging from mid 19th century to the mid 20th century
During the 70’s and 80’s a great deal of information was
generated and analyzed and new tools for demographic
analysis were developed and implemented
The European Fertility Project:
 The project revealed that there were some
inconsistencies between theory and the actual facts

Starting dates of the transition do not always coincide with
those of the industrial revolution
France  Mortality and Fertility decline started before
industrialization
 England  Fertility decline started when industrialization was
way in progress


The relevance of migratory flows between continents
Ireland  High migration outflows kept fertility high
 USA  Fertility declined faster than Mortality. Population grew
thanks to immigration (immigrants tend to have lower fertility)

The European Fertility Project:
 The project revealed that there were some
inconsistencies between theory and the actual facts


Starting dates do not coincide with industrialization,
urbanization or modernization of the economy
Initial levels of mortality and fertility may vary


Final levels after completing the transition may not be the
same in all countries or regions


Importance of late marriage in Europe
Many countries reach fertility rates below generational
replacement levels
The “speed” at which the transition takes place may vary

This is the period during which populations grow dramatically, if
its length cannot be predicted the theory has little practical value
The European Fertility Project:
 The project revealed that there were some
inconsistencies between theory and the actual facts


There is no agreement on which are the mechanisms that
operate driving the transition “tempo”
Kingsley Davis:


Fertility responds to mortality
Frank Notestein:

Both fertility and mortality respond to economic change and
urbanization
The European Fertility Project:
 New contributions to implement the DT model
 Ansley Coale (1973) and the “Necessary Conditions”
Fertility must be dependent from individual decisions
 The cost-benefit of childbearing must shift


Caldwell (1976) and the “Wealth Flows”
End of child labor and mandatory schooling
 Women at paid work (women vs children’s salaries)


Ron Lesthaeghe (1945-) y D. J. van de Kaa (1933-) and the
“Second Demographic Transition” (1986)
Fertility permanently below replacement levels
 Delayed marriage (no longer universal due to increase on
cohabitation) and increase of divorce rates and second marriages
 Changes in values lead to smaller sized households

THE DEMOGRAPHIC TRANSITION
POPULATION STRUCTURE
POPULATION STRUCTURE
POPULATION STRUCTURE
POPULATION STRUCTURE
POPULATION STRUCTURE
http://www.insee.fr/fr/themes/detail.asp?ref_id=irsd2009&page=irweb/sd2009/dd/pyramide/pyramide_aide.htm
RUSSIA 1998
UNITED KINGDOM 2007
GERMANY 2009
Mortality and Fertility in Spain: 1858-1998
Population pyramids of Spain 1960 and 2001
PRACTICAL EXERCISE
 When did the demographic transition started to
occur in Poland?


Decline of mortality
Decline of fertility
 How long did it last? (when was it completed?)
 How has the population pyramid of Poland has
changed over time?
 At which stage of the Demographic transition is
Poland today? Explain why.
Data on Poland
 http://populationpyramid.net/poland/2015/
 http://www.indexmundi.com/poland/age_structure
.html
 http://www.worldlifeexpectancy.com/polandpopulation-pyramid
 http://www.nationmaster.com/countryinfo/profiles/Poland/People
 Etc.