An Essay on the Principle of Population

It is an evident truth that, whatever may be the rate of increase in the means of subsistence, the increase of population must be limited by it, at least after the food has once been divided into the smallest shares that will support life. All the children born, beyond what would be required to keep up the population to this level, must necessarily perish, unless room be made for them by the deaths of grown persons. It has appeared indeed clearly in the course of this work, that in all old states the marriages and births depend principally upon the deaths, and that there is no encouragement to early unions so powerful as a great mortality. To act consistently therefore, we should facilitate, instead of foolishly and vainly endeavouring to impede, the operations of nature in producing this mortality; and if we dread the too frequent visitation of the horrid form of famine, we should sedulously encourage the other forms of destruction, which we compel nature to use. Instead of recommending cleanliness to the poor, we should encourage contrary habits. In our towns we should make the streets narrower, crowd more people into the houses, and court the return of the plague. In the country, we should build our villages near stagnant pools, and particularly encourage settlements in all marshy and unwholesome situations.
*12 But above all, we should reprobate specific remedies for ravaging diseases; and those benevolent, but much mistaken men, who have thought they were doing a service to mankind by projecting schemes for the total extirpation of particular disorders. If by these and similar means the annual mortality were increased from 1 in 36 or 40, to 1 in 18 or 20, we might probably every one of us marry at the age of puberty, and yet few be absolutely starved.

If, however, we all marry at this age, and yet still continue our exertions to impede the operations of nature, we may rest assured that all our efforts will be vain. Nature will not, nor cannot, be defeated in her purposes. The necessary mortality must come, in some form or other; and the extirpation of one disease will only be the signal for the birth of another perhaps more fatal. We cannot lower the waters of misery by pressing them down in different places, which must necessarily make them rise somewhere else; the only way in which we can hope to effect our purpose, is by drawing them off. To this course nature is constantly directing our attention by the chastisements which await a contrary conduct. These chastisements are more or less severe, in proportion to the degree in which her admonitions produce their intended effect. In this country at present these admonitions are by no means entirely neglected. The preventive check to population prevails to a considerable degree, and her chastisements are in consequence moderate: but if we were all to marry at the age of puberty, they would be severe indeed. Political evils would probably be added to physical. A people goaded by constant distress, and visited by frequent returns of famine, could not be kept down but by a cruel despotism. We should approach to the state of the people in Egypt or Abyssinia; and I would ask, whether in that case it is probable, that we should be more virtuous?

Physicians have long remarked the great changes which take place in diseases; and that, while some appear to yield to the efforts of human care and skill, others seem to become in proportion more malignant and fatal. Dr. William Heberden published, not long since, some valuable observations on this subject deduced from the London bills of mortality. In his preface, speaking of these bills, he says, “the gradual changes they exhibit in particular diseases correspond to the alterations, which in time are known to take place in the channels through which the great stream of mortality is constantly flowing.”
*13 In the body of his work, afterwards, speaking of some particular diseases, he observes with that candour which always distinguishes true science; “It is not easy to give a satisfactory reason for all the changes which may be observed to take place in the history of diseases. Nor is it any disgrace to physicians, if their causes are often so gradual in their operation, or so subtle, as to elude investigation.”
*14

I hope I shall not be accused of presumption, in venturing to suggest that, under certain circumstances, such changes must take place; and perhaps without any alteration in those proximate causes, which are usually looked to on these occasions. If this should appear to be true, it will not seem extraordinary that the most skilful and scientific physicians, whose business it is principally to investigate proximate causes, should sometimes search for these causes in vain.

In the country which keeps its population at a certain standard, if the average number of marriages and births be given, it is evident that the average number of deaths will also be given; and, to use Dr. Heberden’s metaphor, the channels, through which the great stream of mortality is constantly flowing, will always convey off a given quantity. Now if we stop up any of these channels, it is perfectly clear, that the stream of mortality must run with greater force through some of the other channels; that is, if we eradicate some diseases, others will become proportionally more fatal. In this case the only distinguishable cause is the damming up a necessary outlet of mortality.
*15 Nature, in the attainment of her great purposes, seems always to seize upon the weakest part. If this part be made strong by human skill, she seizes upon the next weakest part, and so on in succession; not like a capricious deity, with an intention to sport with our sufferings, and constantly to defeat our labours; but, like a kind, though sometimes severe instructor, with the intention of teaching us to make all parts strong, and to chase vise and misery from the earth. In avoiding one fault we are too apt to run into some other; but we always find Nature faithful to her great object, at every false step we commit, ready to admonish us of our errors, by the infliction of some physical or moral evil. If the prevalence of the preventive check to population in a sufficient degree were to remove many of those diseases, which now afflict us, yet be accompanied by a considerable increase of the vice of promiscuous intercourse, it is probable that the disorders and unhappiness, the physical and moral evils arising from this vice, would increase in strength and degree; and, admonishing us severely of our error, would point to the only line of conduct approved by nature, reason and religion, abstinence from marriage till we can support our children, and chastity till that period arrives.

In the case just stated, in which the population and the number of marriages are supposed to be fixed, the necessity of a change in the mortality of some diseases, from the diminution or extinction of others, is capable of mathematical demonstration. The only obscurity which can possibly involve this subject, arises from taking into consideration the effect that might be produced by a diminution of mortality in increasing the population, or in decreasing the number of marriages. That the removal of any of the particular causes of mortality can have no further effect upon population than the means of subsistence will allow, and that it has no certain and necessary influence on these means of subsistence, are facts of which the reader must be already convinced. Of its operation in tending to prevent marriage, by diminishing the demand for fresh supplies of children, I have no doubt; and there is reason to think, that it had this effect in no inconsiderable degree on the extinction of the plague, which had so long and so dreadfully ravaged this country. Dr. Heberden draws a striking picture of the favourable change observed in the health of the people of England since this period; and justly attributes it to the improvements which have gradually taken place, not only in London but in all great towns; and in the manner of living throughout the kingdom, particularly with respect to cleanliness and ventilation.
*16 But these causes would not have produced the effect observed, if they had not been accompanied by an increase of the preventive check; and probably the spirit of cleanliness, and better mode of living, which then began to prevail, by spreading more generally a decent and useful pride, principally contributed to this increase. The diminution in the number of marriages, however, was not sufficient to make up for the great decrease of mortality, from the extinction of the plague, and the striking reduction of the deaths in the dysentery.
*17 While these and some other disorders became almost evanescent, consumption, palsy, apoplexy, gout, lunacy, and the small-pox, became more mortal.
*18 The widening of these drains was necessary to carry off the population which still remained redundant, notwithstanding the increased operation of the preventive check, and the part which was annually disposed of and enabled to subsist by the increase of agriculture.

Dr. Haygarth, in the Sketch of his benevolent plan for the extermination of the casual small-pox, draws a frightful picture of the mortality which has been occasioned by this distemper, attributes to it the slow progress of population, and makes some curious calculations on the favourable effects which would be produced in this respect by its extermination.
*19 His conclusions, however, I fear, would not follow from his premises. I am far from doubting that millions and millions of human beings have been destroyed by the small-pox. But were its devastations, as Dr. Haygarth supposes, many thousand degrees greater than the plague,
*20 I should still doubt whether the average population of the earth had been diminished by them. The small-pox is certainly one of the channels, and a very broad one, which nature has opened for the last thousand years, to keep down the population to the level of the means of subsistence; but had this been closed, others would have become wider, or new ones would have been formed. In ancient times the mortality from war and the plague was incomparably greater than in modern. On the gradual diminution of this stream of mortality, the generation and almost universal prevalence of the small-pox is a great and striking instance of one of those changes in the channels of mortality, which ought to awaken our attention and animate us to patient and persevering investigation. For my own part I feel not the slightest doubt, that, if the introduction of the cow-pox should extirpate the small-pox, and yet the number of marriages continue the same, we shall find a very perceptible difference in the increased mortality of some other diseases. Nothing could prevent this effect but a sudden start in our agriculture; and if this should take place, it will not be so much owing to the number of children saved from death by the cow-pox inoculation, as to the alarms occasioned among the people of property by the late scarcities,
*21 and to the increased gains of farmers, which have been so absurdly reprobated. I am strongly however inclined to believe that the number of marriages will not, in this case, remain the same; but that the gradual light, which may be expected to be thrown on this interesting topic of human inquiry, will teach us how to make the extinction of a mortal disorder a real blessing to us, a real improvement in the general health and happiness of the society.

If, on contemplating the increase of vice which might contingently follow an attempt to inculcate the duty of moral restraint, and the increase of misery that must necessarily follow the attempts to encourage marriage and population, we come to the conclusion, not to interfere in any respect, but to leave every man to his own free choice, and responsible only to God for the evil which he does in either way; this is all I contend for; I would on no account do more; but I contend, that at present we are very far from doing this.

Among the lower classes of society, where the point is of the greatest importance, the poor-laws afford a direct, constant and systematical encouragement to marriage, by removing from each individual that heavy responsibility, which he would incur by the laws of nature, for bringing beings into the world which he could not support. Our private benevolence has the same direction as the poor-laws, and almost invariably tends to encourage marriage, and to equalize as much as possible the circumstances of married and single men.

Among the higher classes of people, the superior distinctions which married women receive, and the marked inattentions to which single women of advanced age are exposed, enable many men, who are agreeable neither in mind nor person, and are besides in the wane of life, to choose a partner among the young and fair, instead of being confined, as nature seems to dictate, to persons of nearly their own age and accomplishments. It is scarcely to be doubted, that the fear of being an old maid, and of that silly and unjust ridicule, which folly sometimes attaches to this came, drives many women into the marriage union with men whom they dislike, or at best to whom they are perfectly indifferent. Such marriages must to every delicate mind appear little better than legal propositions; and they often burden the earth with unnecessary children, without compensating for it by an accession of happiness and virtue to the parties themselves.

Throughout all the ranks of society the prevailing opinions respecting the duty and obligation of marriage cannot but have a very powerful influence. The man who thinks that, in going out of the world without leaving representatives behind him, he shall have failed in an important duty to society, will be disposed to force rather than to repress his inclinations on this subject; and when his reason represents to him the difficulties attending a family, he will endeavour not to attend to these suggestions, will still determine to venture, and will hope that, in the discharge of what he conceives to be his duty, he shall not be deserted by Providence.

In a civilized country, such as England, where a taste for the decencies and comforts of life prevails among a very large class of people, it is not possible that the encouragements to marriage from positive institutions and prevailing opinions should entirely obscure the light of nature and reason on this subject; but still they contribute to make it comparatively weak and indistinct. And till this obscurity is removed, and the poor are undeceived with respect to the principal cause of their poverty, and taught to know, that their happiness or misery must depend chiefly upon themselves, it cannot be said that, with regard to the great question of marriage, we leave every man to his own free and fair choice.