The Reverend Thomas Robert Malthus was born in Surrey in 1766 and died in 1834. He was the son of a clergyman and one of eight children. Malthus was educated at Jesus College, Cambridge, and later became a professor of history and political economy at the East India Company’s College at Haileybury in Hertfordshire. His most famous work, the Essay on the Principles of Population, was published in 1798 when he was thirty-two. It has been interpreted partly as a reaction to the utopian thought of William Godwin (1756–1836) and others, as well as that of Malthus’s own father. It is an extension and formalization of the work of the classical economist Adam Smith (1723–1790) and others who had laid down some of the basic ideas concerning the tendency of population to outstrip resources.
Malthus’s theory, in brief, was that humankind is permanently trapped by the intersection of two “laws.” The first law concerned the rate at which populations can grow. He took the “passion between the sexes” to be constant, and investigations showed that under conditions of “natural” fertility (with early marriage and no contraception, abortion, or infanticide), this would lead to an average of about fifteen live births per woman. This figure is confirmed by modern demography. Given normal mortality at the time, and taking a less than maximum fertility, this will lead to what Malthus called geometrical growth of one, two, four, eight, sixteen, and so on. Only thirty-two such doublings are needed to lead from one original couple to a world population of over six billion persons.
The second premise was that food and other resource production will grow much more slowly. It might double for a generation or two, but could not keep on doubling within an agrarian economy. Thus there could, in the long run, only be an arithmetical or linear growth of the order of one, two, three, four. Incorporated into this later theory was the law of diminishing marginal returns on the further input of resources, especially labor. Underpinning the scheme was the assumption that there was a finite amount of energy available for humans through the conversion of the sun’s energy by living plants and animals. The conclusion was that humankind was trapped, a particular application in the field of demography of the more general pessimism of Adam Smith. Populations would grow rapidly for a few generations, and then be savagely cut back. A crisis would occur, manifesting itself in one (or a combination) of what Malthus called the three “positive” checks acting on the death rate: war, famine, and disease.
After the publication of this theoretical account of the “laws” of the trap, Malthus undertook a great deal of empirical research, traveling through Europe and reading widely in history and anthropology. On the basis of this research, he published what is termed the second edition of The Principles (1803) but which is, in effect, a very different book. Basically, Malthus turned his laws of population into tendencies, likelihoods, or probabilities, to which there were exceptions. The trap became avoidable, for he had discovered in England itself, as well as in Switzerland and Norway, that there were what he called “preventive checks” that could act to suppress fertility to a level that would be in line with resource growth. He divided these checks into “moral restraint” (celibacy and delayed marriage) and “vice” (contraception of all kinds, abortion, and infanticide), of which he disapproved.
Malthus believed that the only force strong enough to overcome the biological drive to mate was a set of desires created in societies and cultures where people were affluent, unequal, and ambitious for social status, and thus willing to forgo the delights of large families for other goals. A mixture of human avarice and human reason could lead people to avoid the Malthusian trap.
Malthus’s work was hugely influential at the practical level. He contributed to the discussion of the reform of England’s Poor Law and to the ideas of how to run the British Empire, many of whose administrators he taught at the East India Company’s College. He is also the only social scientist who has had a revolutionary effect in the biological sciences. His idea that humans normally suffer from very high mortality rates, that war, famine, and disease periodically cut swathes through historical populations, was seminal. Entirely independently, both Charles Darwin (1809–1882) and Alfred Russel Wallace (1823–1913) described how reading Malthus’s Principles provided them with the key to unlock the secret of human evolution, that is, the principle of the survival of the fittest, random variation, and selective retention.
There have been a number of criticisms of the Malthusian framework. His predictions were not fulfilled, at least in the middle term. Malthus wrote before the huge resources of energy locked up in coal and then oil became widely available for human use. For a while, from the middle of the nineteenth century, it looked as if the Malthusian trap was no longer operative. A combination of science (in particular chemistry) and new resources had made it possible to more than double production in each generation. First England, then parts of Europe, Japan, and elsewhere, escaped from the trap. It appeared that Malthus’s laws could be inverted: population grew slowly, resources exponentially.
Ester Boserup (1981) and others have suggested that Malthus mistook cause for effect. It is argued that human ingenuity will find solutions to population pressure and indeed that growth of population is one of the necessary spurs to technical innovation and the development of civilizations. For example, the transformations from tribal to settled peasant civilizations, and then from peasantries to advanced industrial societies, were propelled and made possible by the growth of population.
At a more abstract level, thinkers on the Far Left, such as Chinese Communist leader Mao Zedong (1893–1976), argued that Malthusianism was merely a capitalist philosophy, and that under communism, populations would automatically stabilize at the right level. This view is inverted and reflected by a number of Catholic writers who argue that since God has planned our lives, and since all forms of contraception are immoral, there is no need to worry about the so-called laws of population. There is no trap.
Others point out that there is no simple correlation between rapid population growth and economic advance. For example, since the mid-twentieth century, India has become richer and less famine-prone as its population has grown, while a number of sparsely populated areas in the Horn of Africa have suffered from the Malthusian trap. So there are clearly many intermediary variables.
Yet it is too early to forget Malthus, as the Chinese decided after a generation of the Communist experiment. In the early twenty-first century, as resources reach their limits and the external costs of the massive use of carbon energy become apparent in pollution and global warming, it appears that the ghost of Malthus has arisen again. Likewise, as we realize the ability of microorganisms to outpace human medicine, our ability to overcome disease in an increasingly crowded world seems at risk. Finally, the tensions that lead to war are further aggravated by shortages and crowding.
Malthus’s realistic message that we can postpone the crises of war, famine, and disease but that they will almost certainly strike again in a much more serious way within an increased total population, again makes sense. His advice, that only by stabilizing and probably reducing total population levels through the rational control of fertility, seems ever more salutary. Like all traps, the Malthusian trap can be avoided. Yet it can only be circumvented if people remain constantly aware of its nature as specified by the lucid first theoretical exponent of the biological limits imposed by human nature and the physical world.
SEE ALSO Malthus, Thomas Robert; Population Growth; Population Studies
Boserup, Ester. 1981. Population and Technology. Oxford: Blackwell.
James, Patricia. 1979. Population Malthus: His Life and Times. London: Routledge and Kegan Paul.
Macfarlane, Alan. 1997. The Savage Wars of Peace: England, Japan, and the Malthusian Trap. Oxford: Blackwell.
Malthus, Thomas.  1982. An Essay on the Principle of Population. London: Penguin.
Petersen, William. 1979. Malthus. Cambridge, MA: Harvard University Press.