The English economist Thomas Robert Malthus (1766-1834) was of the classical school and was the first to direct attention to the danger of overpopulation in the modern world.
Thomas Malthus was born at the Rookery near Guilford, Surrey, a small estate owned by his father, Daniel Malthus. After being privately educated, Malthus entered Jesus College, Cambridge, where he was elected to a fellowship at the age of 27. He took religious orders at the age of 31 and held a curacy for a short period.
In 1798 Malthus published his Essay on the Principle of Population. This pamphlet was turned into a fullscale book in 1803 with the aid of demographic data drawn from a number of European countries.
In 1805 Malthus married, and shortly thereafter he was appointed professor of modern history and political economy at the East India Company's College at Haileybury—the first appointment of its kind in England. Much to the amusement of his critics, since he advocated controlling the birthrate, he fathered five children. He died at Haileybury on Dec. 23, 1834, the year that saw the passage of a new Poor Law inspired by his writings.
Few thinkers in the history of social science have aroused as much controversy as Malthus. It is not difficult to find reasons for the furor: he consistently opposed all methods of reforming society which did not act directly to reduce the birthrate, and his own remedies for bringing that about were impractical; he reduced all human suffering to the single principle of the pressure of population on the food supply, and all popular proposals for political or economic reform were exposed as irrelevant and immaterial; and he drove home his theme in one harsh passage after another, suggesting that literally every other possible social order was even worse than the existing one. Those on the left hated him because he seemed to be defending the society they hoped to change, and those on the right disliked him for defending that society as merely a necessary evil.
Toward the end of the 19th century, the discussion died down as the rise in living standards and the decline in fertility, at least in Western countries, took the sting out of the fear of overpopulation. But after World War II the problem of the underdeveloped countries brought Malthus back in favor. Most of the emerging nations of Africa, Asia, and Latin America combine the high birthrates typical of agrarian economies with the low death rates typical of industrialized economies, and there is the danger of too many mouths to feed. It is not surprising, therefore, that Malthus's name crops up repeatedly in debates on population policy in underdeveloped countries. The arguments are very different from those employed in Malthus's own day, but the participants of the debate still line up as for or against the Malthusian theory of population.
From Malthus's writings, one receives the impression of an inflexible fanatic and possibly a misanthrope, but everyone who met Malthus found him kind and benevolent. In terms of the politics of that age, he was almost, but not quite, a "liberal," and his professions of concern over the conditions of the poor must be regarded as perfectly genuine. He had unpleasant truths to tell but he told them, as it were, "for their own good."
Malthus's theory of population is baldly stated in the first two chapters of the Essay. The argument begins with two postulates: "that food is necessary to the existence of man" and "that the passion between the sexes is necessary, and will remain nearly in its present state." The "principle of population" followed from these with the force of deductive logic: "Assuming, then, my postulata as granted, I say, that the power of population is indefinitely greater than the power in the earth to produce subsistence for man. Population, when unchecked, increases in a geometrical ratio. Subsistence increases only in an arithmetical ratio. A slight acquaintance with numbers will show the immensity of the first power in comparison with the second. By that law of nature which makes food necessary to the life of man, the effects of these two unequal powers must be kept equal. This implies a strong and constantly operating check on population from the difficulty of subsistence."
In 1798 Malthus described all the checks, such as infanticide, abortion, wars, plagues, and death from disease or starvation, as resolvable into "misery and vice." In 1803 he added a third pigeonhole, moral restraint, defined as "that restraint from marriage which was not followed by irregular gratification." It should be noted that he did not include birth control achieved by artificial devices. In his view, man was naturally lazy and would not work to provide a livelihood for himself and his family except under the threat of starvation. Birth control, even if it could be adopted, would only remove the incentive to work and would, therefore, amount to more "misery and vice." Moral restraint was something else: it implied postponement of marriage and strict chastity until marriage. He doubted that moral restraint would ever become a common practice, and it is precisely this that gave his doctrine a pessimistic hue: there were remedies against the pressure of population, but they were unlikely to be adopted.
The Malthusian law of population has some resemblance to Newtonian mechanics in assuming tendencies which are never observed as such in the real world: the arithmetical ratio is simply a loose generalization about things as they are, whereas the geometrical ratio is a calculation of things as they might be but never are. The saving clause in the theory is the check of moral restraint, which permits the food supply to increase without a corresponding increase in population. But how shall we know that it is in operation, as distinct from the practice of birth control? By virtue of the fact that the food supply is outstripping the growth of numbers, Malthus would answer. In short, the Malthusian theory explains everything by explaining nothing. No wonder that Malthus's critics bitterly complained that the Malthusian theory could not be disproved, because it was always true on its own terms.
The standard biography of Malthus is by James Bonar, Malthus and His Work (1885; 2d ed. 1924). The great 19th-century debate over the Malthusian doctrine is brilliantly reviewed by Kenneth Smith, The Malthusian Controversy (1951), and Harold A. Boner, Hungry Generations: The 19th-century Case against Malthusianism (1955). Mark Blaug, in Ricardian Economics: A Historical Study (1958), shows how Malthus was received by his fellow economists. George F. McCleary, The Malthusian Population Theory (1953), contains a spirited defense of Malthus's theory as still relevant to the 20th century.