Thomas Malthus published his influential theory of population growth in 1798, proposing that human populations grow geometrically while the food supply grows arithmetically, inevitably leading to famine unless checks on population occur. Malthus suggested "positive checks" like famine and disease and "negative checks" like delayed marriage that reduce birth rates. While controversial, his theory inspired Darwin's concept of the struggle for survival and examined the relationship between population and resources. Malthusian catastrophe predicts population will be forced to return to subsistence levels once it outstrips agricultural production. His theory remains debated but influenced later thinkers exploring limits to economic and population growth.

1. MALTHUS THEORY OF
POPULATION GROWTH
ISTIAQE AHMED TANIM
ROLL: 117646
DEPERTMENT OF GEOGRAPHY & ENVIRONMENT
JAGANNATH UNIVERSITY, DHAKA

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 clearly distinguish between fecundity and fertility.
• 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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