Malthusian Theory of Population Growth

The Malthusian theory of population growth addresses the ability of the human species to [Page 685]increase in population size and to eventually reproduce itself beyond its own ability to grow enough food to sustain this ever-expanding population size within the limits of a defined habitat. Population growth is exponential, while the ability of Homo sapiens to grow food is arithmetic. The consequences of this imbalance in population growth and available food supply would, according to Malthus, either be corrected through human intervention resulting in maintaining an appropriate balance between population size and available food equilibrium or the population would be reduced in size through consequences that include disease, epidemics, famine, and war. In the following text, the authors address the utility of the Malthusian theory by applying its basic tenets to population issues.

Malthus's Principle of Population

Thomas Robert Malthus was born in England in 1766. He was educated at Jesus College in Cambridge. At the age of 22, he became a curate near his family home in Surrey and later in Lincolnshire. In 1805, he was appointed a professor of history and political economy at East India College, Hailerbury, a position he occupied until his death in 1834.

It was during his early years as a rural clergyman when, at age 32, he published anonymously the first edition of his famous work, An Essay on the Principle of Population as It Affects the Future Improvement of Society, with Remarks on the Speculations of Mr. Goodwin, Mr. Condorcet, and Other Writers (1798). This was mainly a deductive book of around 55,000 words, whereas the second edition expanded his theory and provided a great deal of illustrative data, resulting in around 200,000 words. Subsequent editions, ending in the seventh edition published posthumously in 1872, included relatively minor changes.

Malthus's main argument was that the growth of a population results from the natural urge to reproduce. But material resources, such as food and shelter, cannot keep pace with this growth in human population because these material resources increase at an arithmetic rate (1-2-3-4-5-6-7), while population growth occurs at a geometric rate (1-2-4-8-16-32-64-128). If unchecked, population levels would double in size about every 25 years. Because productive capacity can never maintain this rate for long, the growth in population must be continually checked. Malthus based this estimate on observations of actual population growth in the New World, where resources were once abundant for the relatively small population size. Assuming an initial quantity of 1 unit, in 225 years, the population would be at 512 billion—billions more than at time 1. Yet in that same time period, the means of subsistence would only have increased by 10. In 2,000 years, the difference between population and production would almost be incalculable.

Malthus argued that population growth was held in check in two ways, by preventive checks and by positive checks. The major preventive check was moral restraint, such as the postponement of marriage and abstinence from sexual activity. The positive checks included wars, famine, pestilence, and other forms of misery. If the population was left unchecked, it would grow much faster than material resources and lead to human misery, ultimately resulting in poverty. The checks were divided into two subgroups including misery and vice. Misery included things such as hunger, poverty, and disease, and vice included prostitution, venereal disease, homosexuality, and abortion.

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