This document summarizes Thomas Malthus' theory of population growth. It outlines Malthus' key assumptions, including that population grows geometrically while food production grows arithmetically, leading to an imbalance. It also discusses Malthus' ideas around positive and preventive population checks. The document then summarizes several criticisms of Malthus' theory, including that technological advances have allowed food production to keep pace with population growth, and that migration and birth control have disrupted the relationship between population and subsistence assumed by Malthus.
2. BRIEF BACKGROUND
The theory was proposed by Thomas Robert Malthus
in 1798.
These were his views on the effects of population on
food supply.
3. ASSUMPTIONS
Food is necessary to the life of people and, therefore
exercises a strong check on population.
Population is necessarily limited by the means of
subsistence, that is food.
Population increases faster than food production whereas
population increases in geometric progression(2,4,6,8,10).
Food production increases in arithmetic
progression(1,2,3,4,5).
Passion between the sexes is necessary and will remain
unchanged.
Population always increases when the means of subsistence
increases, unless prevented by some powerful checks.
4. ASSUMPTIONS
Food is necessary for human existence
The effects of food supply and population growth have
to be kept equal to reach what is called the Malthusian
Catastrophe.
If this happens, further growth in population would be
prevented
5. Assumptions continued
There are 2 types of checks which can keep population
on a level with the means of subsistence.
These are:
i. Positive checks &
ii. Preventive checks
6. Assumptions continued
Preventive checks
• They exercise their influence on the growth of the
population by bringing down the birth rate.
• This includes abstinence, postponement of marriage which
lowers the fertility rate
• Preventive checks are those checks which are applied by
man
• They arise from man`s fore-sight which enables him to see
distant consequences.
• Malthus saw the distress which frequently visits those who
have large families.
7. Positive checks
Positive checks exercise their influence on the growth
of population by increasing the death rate.
These are applied by nature.
Positive checks to population are various and include
every cause, whether arising from vice or misery which
in any degree contributes to shorten the natural
duration of human life.
These may include hard labour, exposure to the
seasons, extreme poverty, bad nursing of children,
common diseases, wars, plagues and famines.
8. CRITICISM OF THE THEORY
In contrast to Malthus, Ester Boserup emphasized the
positive aspects of a large population
She suggested that the more people there are, the
more hands there are to work.
She argued that necessity is the mother of all
invention.
9. CRITICISMS CONTINUED
Rapid advances in technology and accumulating
capital in advanced countries have been able to strike a
balance between population growth and food supply.
This has been done through the use of fertilisers,
pesticides, better seeds and other agricultural
machinery.
In fact in countries like India due to the Green
Revolution, the rate of increase of food production has
been greater than the rate of population growth.
As such it is not always the case that population
growth exceeds food supply as postulated by Malthus.
10. CRITICISMS CONTINUED
Malthus` theory was context specific, only limited to
England.
He was basing on the unavailability of land in England
at that time, thus resulting in low yields.
Critics argue that he should have considered all types
of production in considering the question of optimum
size of population.
Malthus gave no proof of his assertion that population
increased exactly in geometric progression and food
production increased exactly in arithmetic
progression.
11. CRITICISMS CONTINUED
Growth of population and food supply cannot be
experienced to show the precision or accuracy of such
series.
William(1996) argued that Malthus either failed to see
or simply refused to acknowledge that technological
progress was possible and that its end result was a
higher standard of living, not a lower one.
Improved and efficient means of transportation can
disapprove Malthus` view that food production could
not keep up with growing population.
12. Criticisms continued
To bring the point closer to home, Zimbabwe has been
on the receiving end of droughts and poor harvests.
Food supply has been coming to Zimbabwe by road,
rail or air through international organisations like
USAID, CRS and Christian Care among others.
Henin(1991) argues that migration has helped
maintain the balance between population growth and
subsistence.
Weeks(1996) states that the adoption of birth control
broke the connection between intercourse and fertility
that seemed to be natural to Malthus.
