Malthus, Thomas (1766–1834)

At the end of each day, the world has more than 200,000 more mouths to feed than it had the day before; at the end of each week, it has 1.5 million more mouths to feed; and at the close of each year, it has an additional 75 million mouths to feed. In the world's poorest countries, where population growth is most rapid, the lives of hundreds of millions of people are constantly plagued by hunger and by diseases aggravated by malnutrition. Humankind, entering the 21st century, now numbers well over 6 billion and is caught in an ambush of its own making. Economists call it the “Malthusian trap” after the man, Thomas Robert Malthus, who stated our grim biological predicament most forcefully: Population growth tends to outstrip the supply of food.

Malthus was born in a country house near the town of Dorking, England, the son of a gentleman who prided himself on his advanced ideas and who was an admirer and friend of both Hume and Rousseau. Young Robert (he was never called Thomas) was at first privately educated. In 1784, he went to Jesus College, Cambridge, where he graduated creditably as Ninth Wrangler (an honors degree in mathematics) in 1788. In that same year, he took holy orders and later was appointed to a rectory. In livelihood, however, he was less a “parson,” as his detractors have often chosen to call him, than a college professor, for in 1805 he became the first professor of political economy in the English-speaking world at the new East India College in Hertfordshire, a post he held until his death in 1834. He published his controversial book, An Essay on the Principle of Population as It Affects the Future Improvement of Society, anonymously in London in1798 and brought out a greatly enlarged edition in 1803.

Eighteenth-century thinkers had tended to view population growth as a mark of social well-being; an increase in people was generally taken to imply an increase in wealth. Malthus saw it differently. He began with the awesome redundancy of nature: “Through the animal and vegetable kingdoms,” he wrote, “nature has scattered the seeds of life abroad with the most profuse and liberal hand.” On the other hand, he asserted that nature “has been comparatively sparing in the room and the nourishment necessary to rear them.” It follows that the tendency of populations to multiply, if unchecked by other means, will eventually be checked by starvation; the number of people will simply (and, of course, only temporarily) outstrip the supply of food. This is the most brutal and final of “positive” checks to population growth.

As a former mathematics student, Malthus could not resist a mathematical illustration. He wrote that population can increase geometrically, whereas agricultural production can increase only arithmetically. So, while the population grows “in the ratio of 1, 2, 4,8,16,32,64…,” subsistence will increase only as 1, 2, 3,4, 5, 6, 7, and so on. That was a persuasive argument, although only the first part of it was true on its face; the reproductive potential of any plant or animal species verifies it. Both Charles Darwin and Alfred Russel Wallace, impressed with Malthus's argument, found in it the key to the theory of natural selection. Darwin, 2 years after his round-the-world voyage on the Beagle and puzzling over the origin of species, happened to read Malthus's essay (“for amusement”) and was immediately struck with its relevance to his problem. “A struggle for existence,” Darwin wrote in On the Origin of Species, “inevitably follows from the high rate at which all organic beings tend to increase…. It is the doctrine of Malthus applied with manifold force to the whole animal and vegetable kingdoms.” Darwin reasoned that if more organisms are born than can possibly survive, it will be the best adapted or “fittest” variants that do survive, and with enough new variants over a long period of time, new species could evolve. The second part of Malthus's proposition was problematical because Malthus, depending on his observations of the agricultural practices of the late 18th century, did not foresee the increased food production that would follow the industrial revolution. For more than a century after Malthus's death, food supplies increased far more rapidly than he had predicted. But during the post-World War II period, when antibiotics and other [Page 1523]medical and health improvements caused huge population increases, food supplies would again be inadequate to provide for the world's hungry and malnourished. No doubt, Malthus would now feel vindicated by history.

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