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Hail, Malthus!

Toni Vogel Carey on how easily and dangerously poor reasoning can become accepted wisdom.

A specious argument, says Webster’s Dictionary, is one with “deceptive attractiveness or allure,” giving “a false look of truth or genuineness.” Here is a case in point, one that plunged England into depression for half a century and that had serious, even fatal, consequences for real people.

The Principle of Population

In 1751 Benjamin Franklin predicted that the population of America would double in 20-25 years, so that in another century “the greatest number of Englishmen will be on this Side of the Water.” It was understood that America was unique, with a small population and almost limitless arable land. In Europe, by contrast, Adam Smith noted in Wealth of Nations, “the population cannot be expected to double in less than five hundred years.”

Thomas Robert Malthus (1766-1834) used the American doubling statistic to argue against Condorcet and William Godwin’s utopian vision of a world with “no war, no crimes… no government,” in which everyone “will seek … the good of all.” Malthus’s own father shared this vision; so we have to wonder what Dad thought of Thomas’s first book (1798), An Essay on the Principle of Population, as It Affects The Future Improvement of Society, eight chapters of which were aimed directly at Godwin and Condorcet.

In the first chapter Malthus cites Adam Smith and others on the American population, which “probably without parallel in history … was found to double … in 25 years” or less. He was evidently not aware of Franklin at that point, but included him in the second edition of the Essay in 1803, at which point a U.S. census confirmed that population in America was indeed doubling approximately every 23 years.

For Franklin and Smith this was a cheerful statistic; but it sent Malthus into a funk. “I have read … speculations on the perfectibility of man and of society,” he wrote (meaning Godwin and Condorcet – and Dad, of course), and “I ardently wish for such happy improvements. But I see … unconquerable difficulties in the way to them.”

Malthus begins with two “fixed laws”: first, “that food is necessary to the existence of man; and second, that the passion between the sexes is necessary.” The problem is the “obvious truth,” noted by Smith and others, that “population must always be kept down to the level of the means of subsistence.” And if passion is not restrained, Malthus argues, population will increase “in a geometrical ratio” (meaning multiplication times 2: 1,2,4,8…), whereas the food supply can increase “only in an arithmetical ratio” (meaning addition by 1: 1,2,3,4…). Given these premises, Malthus says, “the argument is conclusive against the perfectibility of the mass of mankind.”

Thomas Robert Malthus
Thomas Robert Malthus, portrait by John Linnell

Misery and Moral Restraint

Six editions of his Essay were published during Malthus’s lifetime, plus a long entry in a supplement to the Encyclopedia Britannica (1823), and a posthumous condensed Summary View of the Principle of Population, published in 1830.

In the first edition Malthus stresses what he calls positive checks on population growth. Some are caused by nature, which he puts under the heading of “misery,” and calls an “absolutely necessary” result of unchecked population growth. Others, which he considers almost as necessary, are caused by ourselves; and he puts these under the heading of “ vice.” Misery includes conditions like “severe labor … insufficient food [and] clothing … diseases and epidemics.” Vice includes wars and “excesses of all kinds [that are] in our power to avoid.” He does not mince words:

“The vices of mankind are active and able ministers of depopulation … and often finish the dreadful work themselves. But should they fail in this war of extermination, sickly seasons, epidemics, pestilence and plague advance … and sweep off … thousands and ten thousands. Should success be still incomplete, gigantic inevitable famine stalks … and with one mighty blow levels the population with the food of the world.”

Malthus was soon having doubts, however; and in 1803 he published a second edition, more than four times as long as the first. He began giving less attention to misery and vice, and more to “moral restraint.” In polite society one did not even speak of abortion or contraception, so moral restraint simply meant chastity. Malthus described it daintily as “abstinence from marriage, either for a time or permanently … with a strictly moral conduct towards the [opposite] sex in the interval.”

The second edition was intended to mitigate some of the “harshest conclusions” of the first. But Malthus continued to maintain that without serious and deliberate checks on population, his geometric and arithmetic ratios “remain in full force.” These ratios appear in all editions – at least six times in the Summary View alone. And the second edition contains very harsh warnings:

“If any man chose to marry without a prospect of being able to support a family, he should have the most perfect liberty so to do. Though to marry in this case is, in my opinion, clearly an immoral act … the punishment [is] provided for it by the laws of nature … Parish [local government] assistance should be denied him, and he should be left to the uncertain support of private charity. He should be taught to know that the laws of nature, which are the laws of God, had doomed him and his family to suffer for disobeying their repeated admonitions.”

Compared with what Malthus considered a softened message, Godwin and Condorcet can sound positively moderate. Godwin (1756-1836) thought, for one thing, that the sex drive could to some extent be sublimated to intellectual pleasures. He also argued in 1820 that given the rate of childhood deaths at the time, in order for the population to double in 25 years, every couple would have to have eight children. He didn’t believe this would occur, and so did not accept Malthus’s geometrical ratio.

Condorcet (1743-94) didn’t live long enough to read Malthus’s Essay, having died in a Parisian prison during Robespierre’s reign of terror. But he wrote this optimistic pre-rebuttal:

“Might there not … come a moment when … the number of people in the world finally exceeding the means of subsistence [we reach] a point … beyond which… the perfectibility of the human race … may never go? … Such a time is still very far from us … But even if we agree that the limit will one day arrive … we can assume that by then men will know [not] foolishly to encumber the world with useless and wretched beings.”

In 1805 Malthus was appointed to the first professorship of Political Economy in England, at the new East India College in Haileybury, where he remained until his death. His Principles of Political Economy, published in 1820, was much more upbeat than the population Essay. Here, in fact, Malthus saw food production sufficient for centuries to come. Yet he did not alter later versions of the population essay accordingly. And those who controlled all the major journals in the field of economics ignored – indeed snubbed – his Principles. Thus when Thomas Carlyle dubbed economics the “dismal science” in 1849, it was due to Malthus’s population theory, not his economic theory.

Tautology and Tendency

At Cambridge University Newton was still revered second only to God. And Malthus, a Cambridge graduate, was doubtless trying to emulate Newton with his population formulas. These were hardly of the caliber of Newton’s abstrusely mathematical Principia. But his ratios could be understood by anyone with a modicum of education, and in the eyes of the public they took on the aura of mathematical certainty, even tautology; they had to be true.

There were a few naysayers, to be sure. John Maynard Keynes, who had high praise for Malthus’s economics, dismissed his population formula as “pseudo-arithmetical.” And he had a point.

There are at least two big problems with the Malthus formulas. One is the arithmetic premise itself – which, after all, is half the theory. And the geometric ratio was old news; so without the arithmetical one Malthus had nothing new to say. But what was his basis for the arithmetic premise? Malthus seems to have simply dreamed this up. Neither Franklin nor Adam Smith had said anything about food increasing arithmetically. And while he repeats it in all later versions, by page 2 of the second edition Malthus is already contradicting it:

“It is observed by Dr. Franklin that there is no bound to the prolific nature of plants or animals but what is made by their crowding and interfering with each other’s means of subsistence. Were the face of the earth … vacant of other plants, it might be gradually sowed and overspread with one kind only, as, for instance, with fennel.” [my italics]

The opening sentence of the Summary View reads: “We cannot fail to be struck with a prodigious power of increase in plants and animals.” In fact “their natural tendency must be to increase in a geometrical ratio” [my italics].

The real problem, then, is not food; it is land. Malthus himself says in the Summary Edition that one thing distinguishing “man from other animals is the power … of very greatly increasing” his means of support; “but this power is obviously limited by the scarcity of land” [my italics]. And land has no tendency at all to increase.

The term ‘tendency’ brings me to Malthus’s other big problem. Newton refers at the beginning of the Principia to “the forces of gravity with which bodies tend to the sun.” What he means, of course, is not that these bodies are likely to crash into the sun, but that they experience a pull towards it, which is counteracted by other forces. By contrast, when ordinary people say that the 8:15 commuter train tends to be late, they mean that this is all too often what does happen. Similarly, when Malthus says in the first Essay that the existing English poor relief laws “tend to increase population,” while doing nothing to increase the food supply, he thinks he is describing the actual world.

The problem is that the term ‘tendency’ is ambiguous between the way Newton uses it and the way it is used in ordinary discourse. As Antony Flew and others have noted, Malthus trades on this ambiguity. When he says in the first Essay that “population tends to increase geometrically,” he means that stringent restrictions must be in place or it will. In later editions, though, his message is that notwithstanding the “prodigious power of increase in vegetables and animals, their actual increase is extremely slow.” In fact, “it very rarely happens that mankind continue to increase in a geometrical progression, [and] it is useless and absurd to lay any stress upon tendencies which never, for any length of time … produce their natural effects.” [some italics added]

Problem? What problem? In the end Malthus is posing a hypothetical, not an actual problem. And hypothetical problems don’t require draconian solutions.

Besides, it’s not as if the existing Elizabethan Poor Laws, in force since 1601, were generous. Nonetheless the New Poor Laws of 1834 tightened the screws, mandating that workhouses be built in every parish as the sole source of poor relief, and that conditions there be worse than what the poorest free laborers could find on their own. Husbands and wives were separated from each other, lest they continue to multiply, and even from their children. Yet even so, workhouses could be better than life outside.

The situation provided plenty of material for Charles Dickens. In A Christmas Carol (1843) Ebenezer Scrooge is asked to donate to the poor. “Are there no prisons,” he snaps? “Are there no workhouses?” But “many cannot go there,” he is told, “and many would rather die.” Scrooge: “If they would rather die, they had better do it, and decrease the surplus population.” As one Dickens scholar remarks, “Malthus hung over England like a cloud.”

Franklin, Smith, Malthus and Darwin

The idea of geometrical population increase was handed down from Franklin to Smith to Malthus, and thence to Charles Darwin – another Cambridge man who would naturally be drawn to mathematical formulae to give his theory a Newtonian cast. But Darwin never mentions the arithmetic ratio. What drew him to Malthus was solely the idea of geometric increase, which leads to a “struggle for existence,” a phrase used both by Malthus and as the title of Darwin’s third chapter of The Origin of Species.

In September 1838, Darwin would later recall, “I happened to read … Malthus on Population, and … it at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones… destroyed. Here, then, I had at last got a theory by which to work.” Malthus, of course, could never have reached this conclusion; his geometrical ratio merely sparked the last piece of the puzzle to fall into place for Darwin.

It has long been a cliché to describe this struggle as “red in tooth and claw.” But the struggle for existence may involve nothing more violent than a plant peeking through a crack in the pavement to get a little sun. And even when the struggle is red in tooth and claw, Malthus seems to miss the fact that humans eat animals, and animals eat other animals. The natural historian Buffon had written in 1751 that if large numbers of herrings were not consumed each year, they would soon cover “the whole surface of the sea.” But then they would be hit by famine, so it is natural and “necessary” that animals “prey upon each other.”

To be sure, population growth is a problem; but it’s not a problem everywhere. The dominant trend in Western countries today is population decline – adults marrying later and having only on average 1.7 children, not enough to replace themselves. The Chinese government imposed a population decrease, which brought its own miseries. But what explains the unforced decrease in the West?

In Wealth of Nations Adam Smith emphasizes “the desire to better one’s condition,” a desire that “comes with us from the womb and never leaves us till we go into the grave.” Why have immigrants historically flocked to the U.S.? To better their condition. Malthus repeats this Smith phrase many times; but he does not factor it into his calculations. His position is that a rise in living standards leads people to have more children. But as Smith dryly remarks in Wealth, “a half-starved Highland woman frequently bears more than twenty children,” while “a pampered fine lady is often incapable of bearing any, and is generally exhausted by two or three.” And the Highlands woman, Smith adds, may fail to have “two who survive.”

Some today take a more depressing view even than Malthus, and unfortunately, perhaps, a more plausible view. If over-population doesn’t get us, they say, the desire to better our condition will. That is because it leads us to demand more and more material goods, depleting the planet of resources and leading to its destruction by global warming. We are doomed, it seems, if not by want, then by plenty.


Scholars often consider editions 2-6 of the population Essay radically different from the first. All editions, though, feature both geometric and arithmetic ratios. And it was the first edition that caught everyone’s attention and had the lasting impact. The only entry for Malthus in Bartlett’s Quotations is the population formula given in the first edition. Malthus could have changed public opinion by speaking out publicly, and retracting the arithmetic ratio before the New Poor Law was enacted in 1834. But he kept mum.

That’s the bad news. The good news is that his word soon ceased to matter much, because although technically English workhouses were not abolished until 1929, and the Poor Law system until 1948, economic growth soon made their harsh measures a thing of the past, and Malthus along with them.

Not until 1968 did the spectre of Malthus rise again, when Paul Ehrlich’s book The Population Bomb predicted that during the 1970s overpopulation would cause the death of hundreds of millions. Many today can remember, as a result, feeling duty-bound not to have more than two children, lest they add to the population. Few remember that in 1980, having survived the ‘70s, the economist Julian Simon called Ehrlich’s dire population predictions “an Oversupply of False Bad News.” Simon made Ehrlich a bet, giving him the choice of ten commodities he predicted would increase in price dramatically over the next decade, due to population pressures. Ehrlich chose mostly metals, whose price decreased by about 30% by 1990. Yet at 85, he is apparently still at Stanford, still defending and even doubling down on his position.

Next came Malthus on Broadway – in a musical, no less, with the repellent title Urinetown. This show ran from 2001-03 and won Tony awards for best book and best score. The plot, long story short, is that because of a severe water shortage, everyone has to pay to pee; and if they can’t pay, they’re sent to Urinetown, which seems to be code for death. All this is supposedly hilarious; and it ends with a rousing “Hail, Malthus!”

More than two centuries have now passed since Malthus first warned of a dire population problem. So how’s he doing? As you might expect, population has risen mostly in poor countries, and spending on consumption (which has more than doubled since 1970) mostly in rich ones, where people can afford to satisfy their every desire for McMansions and whatever else they think will better their condition. According to a United Nations report in 2001, world population more than doubled in the previous half-century. That sounds bad; but it means doubling exponentially (growth of about 1½ percent per year) in 50 years, which falls way short of doubling geometrically in 25.

I am a philosopher, not a demographer. But Malthus’s thesis stands or falls on the worth of his argument; and argumentation is the purview of philosophy. So is ethics; and there are moral as well as logical lessons to be learned from the example of Malthus:

• Don’t use a specious argument just because it sounds good.

• Don’t continue to use it after you know it’s wrong.

• Don’t create ‘alternative facts’ (like that food production grows arithmetically).

• And don’t multiply problems beyond necessity.

© Toni Vogel Carey 2018

Toni Vogel Carey has been a regular contributor to Philosophy Now since 2002 and serves on its US advisory board. She is an independent scholar who publishes in scholarly journals, gives papers at scholarly conferences (Oxford, Sorbonne, Princeton, Aberdeen, Toronto, Rotterdam…) and is concurrently at work on three books.

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