Malthusian theory of population
Thomas Robert Malthus wrote his Essay on Principle of Population in 1798. Although he was led to modify it to some extent in the next edition in 1803, yet in essentials the original theory stands. He was distressed at the prevailing conditions in England and this led him to propound his theory. He deplored "the strange contrast between over care in breeding animals and carelessness in breeding man".
His theory of population is very simple. Malthus based his reasoning on the biological fact that every living organism tends to multiply to an unimaginable extent. According to Huxley's estimate the descendants of a single greenfly, if all survived and multiplied, would, at the end of one summer, weigh down the population of China! Human beings are supposed to double every 25 years and a couple can increase to the size of the present population in 1,750 years!
Such is the prolific nature of every species. The power of procreation is inherent and insistent and must-find expression. Cantillon says "Men multiply like mice in a barn." Production of food, on the other hand, is subject to the law of diminishing return. On the basis of these two premises, Malthus concluded that population tended to outstrip the food supply. If preventive checks, like avoidance of marriage or late marriage or less children per marriage, are not exercised, then positive checks like war, famine and disease, will operate.
The theory propounded by Malthus can be reduced to the following four propositions: —
1. Food is necessary to the life of man and therefore exercises a strong check on population. In other words, population is necessarily limited by the means of subsistence (i.e., food).
2. Population increases faster than food production. Whereas population increases in geometric progression (i.e., 1, 2. 4, 8, 16, etc.), food production increases in arithmetic progression (i.e., 1,2,3,4,5, etc.).
3. Population always increases when the means of subsistence increase, unless prevented by some powerful and obvious checks.
4. There are two types of checks which can keep population on a level with the means of subsistence. They are the preventive and positive checks.
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