‘Malthus
defended his theory of population partly by logic, partly by fact, but not
rigorously by either’.
Malthus theory of population was
described in six editions of his “An Essay on the Principle of Population”
which was published from 1798 to 1826. His theory was based on two assumptions.
The first assumption was that food is necessary for the existence of man. And
the second assumption was that “the passion between the sexes is necessary and
will remain nearly in its present state.”
By his second statement Malthus meant that birth rates are fixed and
therefore there is a constant growth in population. He also stated that these
two “postulates” are laws which are fixed meaning that there is nothing which
can change the power of the earth to produce subsistence and the power of
population increase. From these two statements he concluded that population
grows geometrically but food supply only increases arithmetically. Hence, there
will be a point in the future when population exceeds food supply. To calculate
this point only starting figures of food and population are needed. Following
his argument it can be calculated that population of England
This
diagram shows the geometric growth of population and the arithmetic growth of
food. It also shows the point at which population exceeds food supply,
according to Malthus.
This diagram
shows the decrease in the amount of food per person according to the Malthus
theory of population.
Another conclusion which Malthus drawn from
his two postulates was that when the supply of food exceeds population(which
will eventually happen) the “ checks on population” set up and population
gradually decreases when those checks take place. These checks, he claimed,
were vise and misery. Hence, if his conclusions were right then there is always
a threat of vise and misery as population will always grow at a faster rate
than food. This was his theory of population described in his first book,
however, in his second book he introduced some alterations in response to the
critics of his theory. He introduced a principle of moral restraint which meant
that another check on population can be a decision of a part of population to
deliberately reduce birth rates. He also stated that population increases only
when the means of subsistence increase. Hence, the population is limited by the
means of subsistence. Overall, to make it more clear I would say that Malthus
theory of population can be shortly described as follows: the facts that
population grows geometrically and the means of subsistence grow arithmetically
imply that at some point population will exceed the food supply and at this
point checks on population such as vise, misery and moral restraint will set up
and population will decrease to a natural level, thus this circle will happen
again.
However, it can be argued that his theory
was lacking logic in some parts and evidence in other parts. Firstly, it can be
said that his first book contradicts with the second book. This is because in
the first book he states that “the passion between the sexes” is a fixed law
and it “ will remain constant at its present state”. However, in his second
edition he introduced a check called “ moral restraint” which means the “
passion between the sexes” cannot be constant as the moral restraint implies a
deliberate reduce in the birth rates. Another argument that put Malthus theory
under threat is the lack of logical reasoning from stating his two postulates
to the conclusion that hence the population will grow at a geometrical rate, if
unchecked and the means of subsistence will grow at an arithmetical rate. Therefore,
if his logic is not proved in that sense, all of his conclusions cannot be
drawn and firmly confirmed. Moreover, Malthus did not consider any factors that
can influence the production of the means of subsistence. For example, he
stated that food will grow arithmetically and this growth will be constant,
ignoring the facts of the increase in productivity of land, the production of
food and the technological developments. There is a clear evidence of these
developments in the history. For example, one of the recent developments in the
food production is GMO products which is projected to have a positive impact on
the growth in food production. Malthus clearly missed technological development
out.
Another fact that can undermine
Malthus theory of population is the reliance of his data on population growth
and the absence of any data on the food production growth. Firstly, his data on
population cannot be very reliable because he used very small time scales and
the validity of censuses is questionable. For example, Malthus used a fourteen
years period to calculate that the ratio of births to deaths is 1 to 63 in Russian. Clearly, this
period could have had special features which might explain the growth of
population. Malthus also used the data on population in specific countries, he
did not use the worldwide population data. This means that, for example, the population in some of the other countries
has actually decreased. Therefore, the data could have actually being
distorted. Besides, Malthus was mostly blamed for the absence of any data on
the growth of food production. For example, John Weyland(The Principle of Population and Production, 1816) said that
although Malthus cannot be blamed for the absence of the data on food
production growth as there was not any data available at that time but Malthus
should have considered the agrarian revolution which, for example, kept England
Besides all the critics of Malthusian
population model it still has some logic and at least some evidence to back it
up. Hence, this model can provide with some notions among economists of the
past. However, this model is useless in predicting the future economic events.
This is because of the validity of the data Malthus collected, the absence of
the data on food production, self-contradictions but most importantly he
ignored the fact of technological developments and the possible change in the
pattern of population growth(in his first essay).
This is
important because the growth of technology has a significant impact on the
growth of both food production and population change. For example, a hundred
years ago the use of green houses, soul energy, computerized watering of plant
processes or technologically advanced lines of food productions were hardly
imaginable. Therefore, Malthusian theory of population cannot be used in its
present form.
To sum up, the claim the Malthusian
theory of population is defended partly by logic, partly by fact but not
rigorously by either is justified. This is because although there is some logic
as the fact that if the growth of population is constantly higher that the
growth of the means of subsistence there will be a point when there might be
checks such as vise and misery, however it is was not a logical conclusion that
the growth of population will constantly exceed the growth of food production.
Moreover, although he collected some evidence it cannot back up his theory as
it might not be reliable and most importantly his data was not dynamic.
References.
- Malthus, An Essay On The Principle Of
Population (1798 1st edition) with A Summary View (1830), and
Introduction by Professor Antony Flew. Penguin Classics.
- Malthus, An Essay On The Principle Of
Population (1798 1st edition, plus excerpts 1803 2nd edition),
Introduction by Philip Appleman, and assorted commentary on Malthus edited
by Appleman. Norton Critical Editions. William Peterson, Malthus,
Founder of Modern Demography (1979, 1999).
- William Godwin, Enquiry Concerning Political Justice (1793)
- Malthus,
A Summary View of the Principle of Population(1830)
- W. Hazlitt, A Reply to the Essay on Population by the Rev. T. R. Malthus, (1807)
- John Weyland, The Principle of Population and Production, 1816.
