Of Population We have defined political economy, as being the investigation of the means, by which the greatest number of men in a given state may participate in the highest degree of physical happiness, so far as it depends on government. Two elements, indeed, must always be received in connexion by the legislature; the increase of happiness in intensity, and the diffusion of it among all classes of subjects. It is thus that political economy, on a great scale, becomes the theory of beneficence; and that every thing which does not in the long run concern the happiness of men belongs not to this science.
The human race originating in a single family, has multiplied, and spread itself by degrees over the globe; and much time was of course required, before it could be adjusted to the means of subsistence, which different parts of this globe are capable of supplying. We see this work of nature repeated in new counties, or in a colony established in a desert region. A state which passes from barbarism to a higher stage of civilization, cannot all on a sudden become covered with as many inhabitants as it may comfortably support: as the earth has been wasted several times; as the greater part of its provinces has been by turns plunged into a state of desolation, to arise from it slowly afterwards, we have often had the opportunity of witnessing this spectacle of a growing population. We are accustomed to consider it as the mark of prosperity and good government; and hence our law and constitution all tend to favour this increase, though to increase the symptoms of prosperity is very different from increasing prosperity itself.
Nature has attended to the multiplication of races with a kind of profusion. Although that of man is among the slowest in its progress, it may increase, when all circumstances are favourable, far more quickly than any of our observations indicate. When every man has a great interest in bringing up a family, and has the means of doing so; when all marry, and all as young as nature permits; when they continue to have children till the approaches of old age, their posterity increases so as very quickly to occupy all the allotted space. In several counties, in consequence of the social organization, not above a fourth part of the individuals marry; the rest grow old in celibacy. Yet this fourth is of itself sufficient to keep up the population at the same level. If their brothers and sisters could also marry with the same advantage, the population would be quadrupled in a single generation.
Thus, every nation very soon arrives at the degree of population which it can attain without changing its social institutions. It soon arrives at counting as many individuals as it can maintain with a revenue so limited, and so distributed. If a great transient calamity, a war, a pestilence, a famine, have left a great void in the population, should those events be followed by a period of general security and comfort, this renewing power of human generation is speedily developed; and an observer is astonished to see how few years are required to obliterate all traces of a scourge, which seemed to have unpeopled the earth. But, on the other hand, so soon as this term has been reached, a greater increase of the population is a national calamity; the earth soon consumes those whom it cannot feed. The more numerous births are, the more will mortality display its ravages, to maintain constantly the same level; and this mortality, the effect of misery and suffering, is preceded by the lengthened punishments not of those who perish only, but of those who have struggled with them for existence.
In every country, it is essential to know well those different periods of increase, of stagnation and decline, in order to adapt the laws, and all social institutions, to the circumstances; and not, as has too frequently been done, to hasten, with all our efforts, the destruction we ought most to fear.
So long as a great part of the country is uncultivated as land proper for liberally rewarding rural labour is covered only with spontaneous production; as even the part under tillage is imperfectly worked; as the soil is not rendered healthy, the marshes drained, the hills protected against precipitations, the fields defended against the ruinous force of nature; so long as all this is not done merely for want of hands - it is desirable for the happiness of agriculturists, and for that of the nation living on their labour, that the class of cultivators should be increased, and enabled to accomplish the task reserved for them.
So long as the objects produced by the industrious arts are imperfectly supplied to the consumer, or at least as he cannot procure them except by a sacrifice quite disproportionate to their value; so long as he is constrained to furnish himself coarsely by domestic industry, for want of opportunity to buy furniture, effects, clothes, proper for his use; so long as his enjoyments are restricted by the inconveniences of all the utensils with which he is obliged to content himself, - it is desirable that the manufacturing population increase; since, from the need there is of such a population, it might evidently live in comfort, and contribute to the enjoyment of other classes.
So long as all hands are in such a degree necessary for agriculture, and manufactures, or trade which serves them, that the guardian professions, equally useful to society, are badly filled up - it is desirable that population continue to increase, that so interior order, security of person and property, may be better protected, health better attended to, the soul better nourished, the mind more enlightened; and that society may be externally defended with sufficient force, comprehending even the rapid recruitment of a sea or land army, which consume population.