‘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 doubles every 51 years, for example. His conclusions can also be represented on diagrams.

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 almost as a self-supplying nation.

         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.