Thomas Malthus, in his 1798 essay, presented the theory that population growth outpaces food production, leading to inevitable shortages unless checked by either preventive measures (like moral restraint) or positive checks (like famine and disease). His theory has been critiqued for its assumptions and predictions, yet remains relevant in discussions about modern population growth and resource management, particularly in less developed countries. Malthusian principles suggest that uncontrolled population growth could lead to societal catastrophes due to the imbalance between food supply and population demands.

1. MALTHUS THEORY OF
POPULATION AND GROWTH

2. Thomas Malthus
o Born: February 14, 1766, Surrey, United Kingdom.
o Died: December 29, 1834, Bath, United Kingdom.
o Wrote ‘An essay in the First Principle of
population’ first published in 1798
o Debatable whether the principles of Malthus two
hundred years ago ( that were very revolutionary
and controversial ) have any relevance to the
modern world.
o The world population in 1798 was at nine million
people. We have now passed the seven billion
mark.

3. The Core Principles of Malthus
• Food is necessary for human existence.
• Human population tends to grow faster than the power in the
earth to produce subsistence.
• The effects of these two unequal powers must be kept equal.
• Since humans tend not to limit their population size voluntarily -
“preventive checks” in Malthus’ terminology.

4. Theory of Population
• Malthus very concerned by the condition of the poor and
particularly by rural poverty.
• Because of this he was skeptical of notions of the perfectibility of
society.
• 1st Edition of the Essay is an a priori polemic—the 2nd Edition
included much empirical observation.
• Inspired Darwin’s idea of “the struggle for survival” .

5. Malthus Theory
• In 1798 Thomas Malthus published his views on the effect of
population on food supply. His theory has two basic principles:
• Population grows at a geometric rate i.e. 1, 2, 4, 16, 32, etc.
• Food production increases at an arithmetic rate i.e. 1, 2, 3, 4, etc.

6. Geometric And Arithmetic Ratios
• Population, when unchecked, grows in a geometric ratio.
• Population, if unchecked, will double every 25 years [ a geometric
progression is 1, 2, 4, 8, 16, 32, 64, etc.].
• Evidence from the US where land is abundant.
• Subsistence grows at an arithmetic ratio [1, 2, 3, 4, 5, 6 etc.].
• Subsistence still grows, but due to the different growth ratios
population must eventually press against the means of subsistence.

7. Malthus Theory

8. Malthus (cont.)

9. Proposed Solutions of Malthus
• Malthus suggested that once this ceiling (catastrophe)
had been reached, further growth in population would
be prevented by negative and positive checks. He saw
the checks as a natural method of population.

10. Negative Checks (Decreased Birth Rate)
• Negative Checks were used to limit the population growth. It
included abstinence/ postponement of marriage which lowered
the fertility rate.
• Malthus favored moral restraint (including late marriage and
sexual abstinence) as a check on population growth. However, it is
worth noting that Malthus proposed this only for the working and
poor classes!

11. Positive Checks (Increased Death Rate)
• Positive Checks were ways to reduce population size by
events such as famine, disease, war - increasing the
mortality rate and reducing life expectancy.

12. Malthusian Catastrophe
• A Malthusian catastrophe (also phrased Malthusian check, Malthusian crisis,
Malthusian disaster, or Malthusian nightmare) was originally foreseen to be a
forced return to subsistence-level conditions once population growth had
outpaced agricultural production. Later formulations consider economic
growth limits as well.
• Malthusian catastrophe are very similar to the Iron Law of Wages.
• The main difference is that the Malthusian theories predict what will happen
over several generations or centuries, whereas the Iron Law of Wages predicts
what will happen in a matter of years and decades.

13. Criticism
• As a general rule the following points were raised as criticism against
Malthusian Theory
• The ratio of arithmetical progression of means of subsistence and the geometrical progression of
population growth was never proved.
• In so many cases the theory of the growth of the means of subsistence in arithmetical ratio was
not proved.
• Malthus did not succeed in connecting positive and preventive checks with his theory.
• Friedrich Engels also criticizes the Malthusian catastrophe because Malthus failed to see that
surplus population is connected to surplus wealth, surplus capital, and surplus landed property.
• Ester Boserup wrote that population levels determine agricultural methods, rather than
agricultural methods determining population (via food supply).

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MALTHUSIAN MODEL
• “Essay on the Principle of Population” 1798,
• Unlike Smith, he looked not at wealth, but at
poverty,
• Economic growth is not automatic,
• It is not smooth, but has fluctuations,
• Population growth will overtake growth of
food, leading to increasing poverty.

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ASSUMPTIONS
• Capitalist economy,
• Three classes – workers, landlords and capitalists,
• Total supply of land is fixed,
• Diminishing returns on land,
• Growth of population is directly related to the wage
rate (w).
As w increases, population increases,
and if w decreases, population decreases.

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ECONOMIC GROWTH
• Capitalists invest,
• Workers and landlords only consume
• Increase in investment, leads to increase in capital,
• Increase in capital increases output and growth.
• Per capita income also increases.
• But Malthus felt this will not continue forever.

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POPULATION GROWTH
• Population growth is a function of wage rate.
• When wage rate increases, birth rate also increases,
population increases
• When wage rate decreases, death rate increases,
population decreases.
• So with more growth, more output, and wages
increase,
• This cannot be sustained, due to population growth.

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RATE OF POPULATION GROWTH
• Population grows geometrically (exponentially),
• But food production grows arithmetically (linearly).
• So as economic growth continues, the gap between food and population will
widen,
• This will eventually lead to fall in standards of living, and increasing poverty.
• This is known as the “Iron Law of Wages.”

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POPULATION AND FOOD GROWTH
Time Population
g=a x 2
Food
g=b+2
y1 10 10
y2 20 12
y3 40 14
y4 80 16
y5 160 18
mn
Time
0
Food
Population

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• This is known as the “Malthusian Trap”
• When economic growth takes place, it will not improve the conditions of workers,
• Higher growth, leads to increase in wage rates,
• Higher wage rates leads to increase in population. Demand for food rises,
• But food does not grow at the same rate as population.
• The increasing gap, leads to poverty, hunger, death, more misery.

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SOLUTION
• Malthus suggests that population growth should be
controlled.
• This can be done by ‘Voluntary’ or ‘Positive’ checks,
• Such as birth control, late marriages, family planning.
• Otherwise, there will be ‘Negative’ checks to
population growth –
• Famines, floods, wars, diseases will increase death
rate, and bring population down to manageable
levels.

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CRITICISM
• Pessimistic view of the economy
• Data of developed countries shows that as PCY increased, birth rates automatically
decreased.
• Called “demographic transition”
• Output of food has also increased, due to improved technology
• Imports and free trade of food can take place, Malthus was for Protection.

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• But:
• Malthusian theory is still applicable to less developed countries.
• Increasing population is consuming all the surplus, nothing available for investment.
• Inferior land is used, and output falls,
• Technology is inferior,
• In recent times, the depletion of natural resources, has shown the importance of
Malthusian theory of exponential growth in a finite world.

24. THANK YOU ALL