# Principles of Political Economy (J.S. Mill, 1871), vol. 1/Book I, Chapter X

CHAPTER X.
§ 1. We have now successively considered each of the agents or conditions of production, and of the means by which the efficacy of these various agents is promoted. In order to come to an end of the questions which relate exclusively to production, one more, of primary importance, remains.
Production is not a fixed, but an increasing thing. When not kept back by bad institutions, or a low state of the arts of life, the produce of industry has usually tended to increase; stimulated not only by the desire of the producers to augment their means of consumption, but by the increasing number of the consumers. Nothing in political economy can be of more importance than to ascertain the law of this increase of production; the conditions to which it is subject: whether it has practically any limits, and what these are. There is also no subject in political economy which is popularly less understood, or on which the errors committed are of a character to produce, and do produce, greater mischief.
We have seen that the essential requisites of production are three—labour, capital, and natural agents; the term capital including all external and physical requisites which are products of labour, the term natural agents all those which are not. But among natural agents we need not take into account those which, existing in unlimited quantity, being incapable of appropriation, and never altering in their qualities, are always ready to lend an equal degree of assistance to production, whatever may be its extent; as air, and the light of the sun. Being now about to consider the impediments to production, not the facilities for it, we need advert to no other ​natural agents than those which are liable to be deficient either in quantity or in productive power. These may be all represented by the term land. Land, in the narrowest acceptation, as the source of agricultural produce, is the chief of them; and if we extend the term to mines and fisheries— to what is found in the earth itself, or in the waters which partly cover it, as well as to what is grown or fed on its surface, it embraces everything with which we need at present concern ourselves.
We may say, then, without a greater stretch of language than under the necessary explanation is permissible, that the requisites of production are Labour, Capital, and Land. The increase of production, therefore, depends on the properties of these elements. It is a result of the increase either of the elements themselves, or of their productiveness. The law of the increase of production must be a consequence of the laws of these elements; the limits to the increase of production must be the limits, whatever they are, set by those laws. We proceed to consider the three elements successively, with reference to this effect; or in other words, the law of the increase of production, viewed in respect of its dependence, first on Labour, secondly on Capital, and lastly on Land.
§ 2. The increase of labour is the increase of mankind; of population. On this subject the discussions excited by the Essay of Mr. Malthus have made the truth, though by no means universally admitted, yet so fully known, that a briefer examination of the question than would otherwise have been necessary will probably on the present occasion suffice.
The power of multiplication inherent in all organic life may be regarded as infinite. There is no one species of vegetable or animal, which, if the earth were entirely abandoned to it, and to the things on which it feeds, would not in a small number of years overspread every region of the globe, of which the climate was compatible with its existence. The ​degree of possible rapidity is different in different orders of beings; but in all it is sufficient, for the earth to be very speedily filled up. There are many species of vegetables of which a single plant will produce in one year the germs of a thousand; if only two come to maturity, in fourteen years the two will have multiplied to sixteen thousand and more. It is but a moderate case of fecundity in animals to be capable of quadrupling their numbers in a single year; if they only do as much in half a century, ten thousand will have swelled within two centuries to upwards of two millions and a half. The capacity of increase is necessarily in a geometrical progression: the numerical ratio alone is different.
To this property of organized beings, the human species forms no exception. Its power of increase is indefinite, and the actual multiplication would be extraordinarily rapid, if the power were exercised to the utmost. It never is exercised to the utmost, and yet, in the most favourable circumstances known to exist, which are those of a fertile region colonized from an industrious and civilized community, population has continued, for several generations, independently of fresh immigration, to double itself in not much more than twenty years. That the capacity of multiplication in the human species exceeds even this, is evident if we consider how great is the ordinary number of children to a family, where the climate is good and early marriages usual; and how small a proportion of them die before the age of maturity, in the present state of hygienic knowledge, where the locality is healthy, and the family adequately provided with the means of living. It is a very low estimate of the capacity of increase, if we only assume, that in a good sanitary condition of the people, each generation may be double the number of the generation which preceded it.
​Twenty or thirty years ago, these propositions might still have required considerable enforcement and illustration; but the evidence of them is so ample and incontestable, that they have made their way against all kinds of opposition, and may now be regarded as axiomatic: though the extreme reluctance felt to admitting them, every now and then gives birth to some ephemeral theory, speedily forgotten, of a different law of increase in different circumstances, through a providential adaptation of the fecundity of the human species to the exigencies of society. The obstacle to a just understanding ​of the subject does not arise from these theories, but from too confused a notion of the causes which, at most times and places, keep the actual increase of mankind so far behind the capacity.
§ 3. Those causes, nevertheless, are in no way mysterious. What prevents the population of hares and rabbits from overstocking the earth? Not want of fecundity, but causes very different: many enemies, and insufficient subsistence; not enough to eat, and liability to be eaten. In the human race, which is not generally subject to the latter inconvenience, the equivalents for it are war and disease. If the multiplication of mankind proceeded only, like that of the other animals, from a blind instinct, it would be limited in the same manner with theirs; the births would be as numerous as the physical constitution of the species admitted of, and the population would be kept down by deaths. But the conduct of human creatures is more or less influenced by foresight of consequences, and by impulses superior to mere animal instincts: and they do not, therefore, propagate like swine, but are capable, though in very unequal degrees, of being withheld by prudence, or by the social affections, from giving existence to beings born only to misery ​and premature death. In proportion as mankind rise above the condition of the beasts, population is restrained by the fear of want rather than by want itself. Even where there is no question of starvation, many are similarly acted upon by the apprehension of losing what have come to be regarded as the decencies of their situation in life. Hitherto no other motives than these two have been found strong enough, in the generality of mankind, to counteract the tendency to increase. It has been the practice of a great majority of the middle and the poorer classes, whenever free from external control, to marry as early, and in most countries to have as many children, as was consistent with maintaining themselves in the condition of life which they were born to, or were accustomed to consider as theirs. Among the middle classes, in many individual instances, there is an additional restraint exercised from the desire of doing more than maintaining their circumstances—of improving them; but such a desire is rarely found, or rarely has that effect, in the labouring classes. If they can bring up a family as they were themselves brought up, even the prudent among them are usually satisfied. Too often they do not think even of that, but rely on fortune, or on the resources to be found in legal or voluntary charity.
In a very backward state of society, like that of Europe in the Middle Ages, and many parts of Asia at present, population is kept down by actual starvation. The starvation does not take place in ordinary years, but in seasons of scarcity, which in those states of society are much more frequent and more extreme than Europe is now accustomed to. In these seasons actual want, or the maladies consequent on it, carry off numbers of the population, which in a succession of favourable years again expands, to be again cruelly decimated. In a more improved state, few, even among the poorest of the people, are limited to actual necessaries, and to a bare sufficiency of those: and the increase is kept within bounds, not by excess of deaths, but by limitation of births. The ​limitation is brought about in various ways. In some countries, it is the result of prudent or concientious self-restraint. There is a condition to which the labouring people are habituated; they perceive that by having too numerous families, they must sink below that condition, or fail to transmit it to their children; and this they do not choose to submit to. The countries in which, so far as is known, a great degree of voluntary prudence has been longest practised on this subject, are Norway and parts of Switzerland. Concerning both, there happens to be unusually authentic information; many facts were carefully brought together by Mr. Malthus, and much additional evidence has been obtained since his time. In both these countries the increase of population is very slow; and what checks it, is not multitude of deaths, but fewness of births. Both the births and the deaths are remarkably few in proportion to the population; the average duration of life is the longest in Europe; the population contains fewer children, and a greater proportional number of persons in the vigour of life, than is known to be the case in any other part of the world. The paucity of births tends directly to prolong life, by keeping the people in comfortable circumstances; and the same prudence is doubtless exercised in avoiding causes of disease, as in keeping clear of the principal cause of poverty. It is worthy of remark that the two countries thus honourably distinguished, are countries of small landed proprietors.
There are other cases in which the prudence and forethought, which perhaps might not be exercised by the people themselves, are exercised by the state for their benefit; marriage not being permitted until the contracting parties can show that they have the prospect of a comfortable support. Under these laws, of which I shall speak more fully hereafter, the condition of the people is reported to be good, and the illegitimate births not so numerous as might be expected. There are places, again, in which the restraining cause seems to be not so much individual prudence, as some general and ​perhaps even accidental habit of the country. In the rural districts of England, during the last century, the growth of population was very effectually repressed by the difficulty of obtaining a cottage to live in. It was the custom for unmarried labourers to lodge and board with their employers; it was the custom for married labourers to have a cottage: and the rule of the English poor laws by which a parish was charged with the support of its unemployed poor, rendered landowners averse to promote marriage. About the end of the century, the great demand for men in war and manufactures, made it be thought a patriotic thing to encourage population: and about the same time the growing inclination of farmers to live like rich people, favoured as it was by a long period of high prices, made them desirous of keeping inferiors at a greater distance, and, pecuniary motives arising from abuses of the poor laws being superadded, they gradually drove their labourers into cottages, which the landlords now no longer refused permission to build. In some countries an old standing custom that a girl should not marry until she had spun and woven for herself an ample trousseau (destined for the supply of her whole subsequent life,) is said to have acted as a substantial check to population. In England, at present, the influence of prudence in keeping down multiplication is seen by the diminished number of marriages in the manufacturing districts in years when trade is bad.
But whatever be the causes by which population is anywhere limited to a comparatively slow rate of increase, an acceleration of the rate very speedily follows any diminution of the motives to restraint. It is but rarely that improvements in the condition of the labouring classes do anything more than give a temporary margin, speedily filled up by an increase of their numbers. The use they commonly choose to make of any advantageous change in their circumstances, is to take it out in the form which, by augmenting the population, deprives the succeeding generation of the benefit. ​Unless, either by their general improvement in intellectual and moral culture, or at least by raising their habitual standard of comfortable living, they can be taught to make a better use of favourable circumstances, nothing permanent can be done for them; the most promising schemes end only in having a more numerous, but not a happier people. By their habitual standard, I mean that (when any such there is) down to which they will multiply, but not lower. Every advance they make in education, civilization, and social improvement, tends to raise this standard; and there is no doubt that it is gradually, though slowly, rising in the more advanced countries of Western Europe. Subsistence and employment in England have never increased more rapidly than in the last forty years, but every census since 1821 showed a smaller proportional increase of population than that of the period preceding; and the produce of French agriculture and industry is increasing in a progressive ratio, while the population exhibits in every quinquennial census, a smaller proportion of births to the population.
The subject, however, of population, in its connexion with the condition of the labouring classes, will be considered in another place: in the present we have to do with it solely as one of the elements of Production: and in that character we could not dispense with pointing out the unlimited extent of its natural powers of increase, and the causes owing to which so small a portion of that unlimited power is for the most part actually exercised. After this brief indication, we shall proceed to the other elements.
* ↑ This has been disputed; but the highest estimate I have seen of the term which population requires for doubling itself in the United States, independently of immigrants and of their progeny—that of Mr. Carey—does not exceed thirty years.
* ↑ One of these theories, that of Mr. Doubleday, may be thought to require a passing notice, because it has of late obtained some followers, and because it derives a semblance of support from the general analogies of organic life. This theory maintains that the fecundity of the human animal, and of all other living beings, is in inverse proportion to the quantity of nutriment: that an underfed population multiplies rapidly, but that all classes in comfortable circumstances are, by a physiological law, so unprolific, as seldom to keep up their numbers without being recruited from a poorer class. There is no doubt that a positive excess of nutriment, in animals as well as in fruit trees, is unfavourable to reproduction; and it is quite possible, though by no means proved, that the physiological conditions of fecundity may exist in the greatest degree when the supply of food is somewhat stinted. But any one who might be inclined to draw from this, even if admitted, conclusions at variance with the principles of Mr. Malthus, needs only be invited to look through a volume of the Peerage, and observe the enormous families, almost universal in that class; or call to mind the large families of the English clergy, and generally of the middle classes of England. It is, besides, well remarked by Mr. Carey, that, to be consistent with Mr. Doubleday's theory, the increase of the population of the United States, apart from immigration, ought to be one of the slowest on record. Mr. Carey has a theory of his own, also grounded on a physiological truth, that the total sum of nutriment received by an organized body directs itself in largest proportion to the parts of the system which are most used; from which he anticipates a diminution in the fecundity of human beings, not through more abundant feeding, but through the greater use of their brains incident to an advanced civilization. There is considerable plausibility in this speculation, and experience may hereafter confirm it. But the change in the human constitution which it supposes, if ever realized, will conduce to the expected effect rather by rendering physical self-restraint easier, than by dispensing with its necessity; since the most rapid known rate of multiplication is quite compatible with a very sparing employment of the multiplying power.
* ↑ Mr. Carey expatiates on the absurdity of supposing that matter tends to assume the highest form of organization, the human, at a more rapid rate than it assumes the lower forms, which compose human food; that human beings multiply faster than turnips and cabbages. But the limit to the increase of mankind, according to the doctrine of Mr. Malthus, does not depend on the power of increase of turnips and cabbages, but on the limited quantity of the land on which they can be grown. So long as the quantity of land is practically unlimited, which it is in the United States, and food, consequently, can be increased at the highest rate which is natural to it, mankind also may, without augmented difficulty in obtaining subsistence, increase at their highest rate. When Mr. Carey can show, not that turnips and cabbages, but that the soil itself, or the nutritive elements contained in it, tend naturally to multiply, and that too at a rate exceeding the most rapid possible increase of mankind, he will have said something to the purpose. Till then, this part at least of his argument may be considered as non-existent.