Thomas Malthus (1766–1834), mathematician and clergyman, published his Essay on the Principle of Population in 1798, arousing a storm of abuse and controversy. By applying scientific thought to the question of population, which no one had done before, he contrived to show that it was impossible – despite the dreams of Utopian philosophers – for the whole of mankind to live in happiness and plenty. Idealists and reformers were enraged by Malthus’s demonstration that social welfare, if it consisted of cash handouts to the poor, did more harm than good. Co-founder of Communism, Friedrich Engels denounced ‘this vile, infamous theory, this revolting blasphemy against nature and mankind’.

Malthus’s case – that food supply increases only arithmetically (1, 2, 3, 4, 5, etc.), whereas population increases geometrically (1, 2, 4, 8,16, 32, etc.) – has been modified by developments in agricultural technology. Also, his contention that ‘misery’ (war, disease, starvation, etc.) and ‘vice’ (abortion, prostitution, etc.) are the only possible checks to population fails to take account of contraception, which was not publicly advocated in England until the 1820s. But despite its flaws Malthus’s theory did not exaggerate the prodigious effects of unchecked population increase. In 1956 Professor W. A. Lewis calculated that if the world population were to double every 25 years (a rate of increase currently observable in some parts of Africa and Asia), it would reach 173,500 thousand million by the year 2330, ‘at which time there would be standing room only, since this is the number of square yards on the land surface of the earth’.

Population, when unchecked, increases in a geometrical ratio. Subsistence increases only in an arithmetical ratio. A slight acquaintance with numbers will shew the immensity of the first power in comparison of the second.

By that law of our 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. This difficulty must fall somewhere and must necessarily be severely felt by a large portion of mankind.

Through the animal and vegetable kingdoms, nature has scattered the seeds of life abroad with the most profuse and liberal hand. She has been comparatively sparing in the room and the nourishment necessary to rear them. The germs of existence contained in this spot of earth, with ample food, and ample room to expand in, would fill millions of worlds in the course of a few thousand years. Necessity, that imperious all pervading law of nature, restrains them within the prescribed bounds. The race of plants and the race of animals shrink under this great restrictive law. And the race of man cannot, by any efforts of reason, escape from it. Among plants and animals its effects are waste of seed, sickness, and premature death. Among mankind, misery and vice. The former, misery, is an absolutely necessary consequence of it. Vice is a highly probable consequence, and we therefore see it abundantly prevail, but it ought not, perhaps, to be called an absolutely necessary consequence. The ordeal of virtue is to resist all temptation to evil.

This natural inequality of the two powers of population and of production in the earth, and that great law of our nature which must constantly keep their effects equal, form the great difficulty that to me appears insurmountable in the way to the perfectibility of society. All other arguments are of slight and subordinate consideration in comparison of this. I see no way by which man can escape from the weight of this law which pervades all animated nature. No fancied equality, no agrarian regulations in their utmost extent, could remove the pressure of it even for a single century. And it appears, therefore, to be decisive against the possible existence of a society, all the members of which should live in ease, happiness, and comparative leisure; and feel no anxiety about providing the means of subsistence for themselves and families.

Consequently, if the premises are just, the argument is conclusive against the perfectibility of the mass of mankind … The poor laws of England tend to depress the general condition of the poor in two ways. Their first obvious tendency is to increase population without increasing the food for its support. A poor man may marry with little or no prospect of being able to support a family in independence. They may be said therefore in some measure to create the poor which they maintain, and as the provisions of the country must, in consequence of the increased population, be distributed to every man in smaller proportions, it is evident that the labour of those who are not supported by parish assistance will purchase a smaller quantity of provisions than before and consequently more of them must be driven to ask for support.

Secondly, the quantity of provisions consumed in workhouses upon a part of the society that cannot in general be considered as the most valuable part diminishes the shares that would otherwise belong to more industrious and more worthy members, and thus in the same manner forces more to become dependent. If the poor in the workhouses were to live better than they now do, this new distribution of the money of the society would tend more conspicuously to depress the condition of those out of the workhouses by occasioning a rise in the price of provisions.

Fortunately for England, a spirit of independence still remains among the peasantry. The poor laws are strongly calculated to eradicate this spirit. They have succeeded in part, but had they succeeded as completely as might have been expected their pernicious tendency would not have been so long concealed.

Hard as it may appear in individual instances, dependent poverty ought to be held disgraceful. Such a stimulus seems to be absolutely necessary to promote the happiness of the great mass of mankind, and every general attempt to weaken this stimulus, however benevolent its apparent intention, will always defeat its own purpose. If men are induced to marry from a prospect of parish provision, with little or no chance of maintaining their families in independence, they are not only unjustly tempted to bring unhappiness and dependence upon themselves and children, but they are tempted, without knowing it, to injure all in the same class with themselves. A labourer who marries without being able to support a family may in some respects be considered as an enemy to all his fellow-labourers …

The evil is perhaps gone too far to be remedied, but I feel little doubt in my own mind that if the poor laws had never existed, though there might have been a few more instances of very severe distress, yet that the aggregate mass of happiness among the common people would have been much greater than it is at present.

I was suffering from a sharp attack of intermittent fever‚ and every day during the cold and succeeding hot fits had to lie down for several hours, during which time I had nothing to do but to think over any subject then particularly interesting to me. One day something brought to my recollection Malthus’s ‘Principles of Population’, which I had read twelve years before. I thought of his clear exposition of ‘the positive checks to increase’ – disease, accidents, war and famine – which keep down the population of savage races to so much lower an average than that of more civilized peoples. It then occurred to me that these causes or their equivalents are continually acting in the case of animals also; and as animals usually breed much more rapidly than does mankind, the destruction every year from these causes must be enormous in order to keep down the numbers of each species … as otherwise the world would have been densely crowded with those that breed more quickly … Why do some die and some live? And the answer was clearly, that on the whole the best fitted live. From the effects of disease the most healthy escaped; from enemies, the strongest, the swiftest or the most cunning; from famine, the best hunters or those with the best digestion; and so on. Then it suddenly flashed upon me that this self-acting process would necessarily improve the race, because in every generation the inferior would inevitably be killed off and the superior would remain – that is, the fittest would survive … I awaited anxiously for the termination of my fit so that I might at once make notes for a paper on the subject.