Joseph J. Spengler
Ancient and Medieval Writings on Population
Germs of certain ideas which have figured prominently in recent theoretical works on population can be found in very ancient writings. The thesis that excessive growth of population may reduce output per worker, depress the level of living of the masses, and engender strife is of great antiquity. It appears in the works of Confucius and his school, as well as in the works of other schools of ancient Chinese philosophers. In fact, these writers had the concept of optimum numbers, so far as the population engaged in agriculture is concerned. They postulated an ideal proportion between land and population, any major deviation from which would create poverty. They held the government primarily responsible for maintaining such a proportion by moving people from over-populated to underpopulated areas, though they noted that governmental action was reinforced at times by spontaneous migration.
These ancient Chinese writers also paid some attention to another topic which has occupied much space in subsequent literature on population theoryânamely, the checks to population growth. They observed that mortality increases when the food supply is insufficient; that premature marriage makes for high infant mortality rates; that war checks population growth; and that costly marriage ceremonies reduce the marriage rate. They did not attempt to show how the variations of mortality, fertility, and nuptiality, as well as migration, might affect the balance between population and resources.1
Plato and Aristotle2 considered the question of optimum size of population in their discussions of the ideal conditions of a city-state in which manâs potentialities could be fully developed and his âhighest goodâ realized. Their treatment of this question was by no means limited to its economic aspects. The âgood lifeâ could be attained, they believed, only if the population was large enough to be economically self-sufficient and capable of defending itself, but not too large for constitutional government. Self-sufficiency required the possession of enough territory to supply the needs of the people and to make possible a moderate level of living.3 However, neither Plato nor Aristotle inquired explicitly into the relation between population density and per capita output or the connexion between the size of the population and the opportunities for division of labour. Plato specified 5,040 [total population about 60,000: Ed.] as the number of citizens âmost likely to be useful to all citiesâ, because it has âfifty-nine divisorsâ and âwill furnish numbers for war and peace, and for all contracts and dealings, including taxes and divisions of the land.â4 Aristotle was less specific with regard to the optimum number, but he held that unless the size of the population was appropriately limited, poverty would be the result, for land and property could not be increased as rapidly as population would grow; civil discord would ensue, and it would be impossible for the government to function effectively.5
The views of Plato and Aristotle regarding the means of controlling the size of population are noteworthy. Plato proposed to restrict births, if necessary by restraining the reproduction of those âin whom generation is affluentâ; if a higher birth rate were required, he would achieve it by means of rewards, stigmas, advice and rebuke to the young men from their elders. Should the population grow too large in spite of these precautions, it could be reduced by colonization, and immigration could be used if absolutely necessary to replenish a population greatly diminished by wars or epidemics.6 Aristotle mentioned child-exposure and abortion as suitable means of preventing an excessive number of children, and in this connection paid some attention to eugenics.7
The Romans, like the Chinese, viewed population questions in the perspective of a great empire rather than a small city-state. They were less conscious than the Greeks of possible limits to population growth and more alert to its advantages for military and related purposes. Perhaps partly because of this difference in outlook, Roman writers paid less attention than the Greeks to population theory, but were much concerned with the practical problem of stimulating population increase. Their attitude was indicated by their disapproval of celibacy, their writings in defence of marriage and procreation, and by their legislation aimed at raising the marriage and birth rates.8 Cicero, touching upon this subject, rejected Platoâs communism in wives and children and held that the Stateâs population must be kept up by monogamous marriageâ9. He listed various checks to population growth-floods, epidemics, famines, wild animals, war, revolutionâbut did not attempt to state a general theory of the determinants of population increase or decrease.10
Medieval Christian writers considered questions of population almost entirely from a moral and ethical standpoint. Since they were concerned more with the next world than with the present, they did not stress material values. Their doctrines were mainly populationist, but they placed less emphasis than earlier Hebrew and other religious writers on maxims adjuring men to multiply and people the earth.11 On the one hand, they condemned abortion, infanticide, child-exposure, divorce, and polygamy; on the other hand, they glorified virginity and continence, considered celibacy superior to marriage though suited only to certain persons, and frowned on second marriage.12 Unlike the Greeks and Romans, early medieval authors did not attach great importance to population growth as a source of strength for the State, but in time, with the reappearance of Aristotleâs influence, this point was again emphasized.13 Some medieval defenders of ecclesiastical celibacy resorted to economic arguments of a vaguely proto-Malthusian character, noting the extent to which the population of the world had grown, attributing observed poverty and want to this cause, and citing pestilence, famine, war, etc., as natureâs means of pruning excess population.14 The prevailing tendency, however, was to favour population increase, as it had been in earlier times. The high rates of mortality which were found throughout the world, and the constant threat of sudden depopulation through famines, epidemics and wars predisposed ancient and medieval writers alike to favour maintenance of a high birth rate.15
Arguments in favour of population increase predominated in the writings of European authors on population during the early modern, as well as the medieval, period. The discovery of the New World, the increase of commerce between Europe and Asia, the rise of national states, and the Protestant Reformation16 brought some revision of the terms of discussion of population questions, but until the latter part of the eighteenth century there was no widespread change of attitude with regard to the desirability of a large and increasing population.17
Two writers of the period now under consideration require special mention. One is Ibn Khaldun, a fourteenth-century Muslim author, who expounded in detail a theory of cyclical variations of population and their relation to economic, political, and social-psychological conditions.18 Khaldunâs writings, though perceptive, apparently had little influence in the East and remained unknown in the West until the nineteenth century. The other writer worthy of special note is Botero, an Italian of the sixteenth century, who set forth ably some of the arguments later developed by Malthus. Botero held that manâs generative powers operate with undiminished vigour irrespective of his numbers, whereas manâs capacity to produce subsistence is subject to limits. The limitation of subsistence limits population through war, strife and various secondary checks to which the struggle for a limited subsistence gives rise. Presumably, Botero believed that the limits of subsistence had been reached, and that a further increase in population could not in general augment the flow of the means of support, since he declared that the population and the supply of food had remained constant for three thousand years or longer.19
Mercantilist and Related Theories
The mercantilist and cameralist schools of political economy, which flourished in Europe during much of the seventeenth and eighteenth centuries, emphasized the economic, political and military advantages of a large and growing population,20 and favoured various measures to stimulate population growth.21 Writers in these traditions were concerned primarily with the ways and means of increasing the wealth and power of the state, and in particular its supplies of precious metals. Their aim was not to raise per capita income but to increase either the aggregate national income or the excess of national income over the wage-cost of production, which excess was viewed as a source of tax revenues for the state. Population growth would augment national income and at the same time depress the hourly wage rate, giving the workers an incentive to work longer hours and widening the margin between national income and wage costs. The benefit to the state would be especially great if the additional labour supply were used to develop manufactures, for manufactured goods could be exchanged abroad for gold and silver. Many writers thought that manufacturing yielded increasing returns, presumably because of the greater possibilities of division of labour in a larger population; some held that agriculture was subject to diminishing returns and that there were limits to its expansion.22 It was generally recognized that a large labour supply was useful only if it could be employed, and certain writers stated the thesis that population was determined by the amount of employment that could be made available.
The mercantilists paid special attention to the relation between population and foreign trade. Cantillon suggested that, if the agriculture of a country could not be expanded in proportion to the population, or if such an expansion would involve diminishing returns, additional agricultural products could be obtained abroad in exchange for manufactured goods.23 Steuart put it that âworkâ should be exported and âmatterâ imported so long as satisfactory terms of trade could be obtained; otherwise, population would have to be contained within the limits of home-produced subsistence.24 Several writers remarked that the size of a countryâs population was determined by the amount of subsistence that could be produced at home or obtained abroad. Few mercantilist or cameralist writers attempted a systematic explanation of population changes, but they did discuss a variety of checks to population growth: plagues, wars, accidents, uncongenial climate, infecundity due to urbanization and other causes, vice, abortion, deferment of marriage, celibacy, monopoly, luxurious living, emigration, etc.25
The period in which mercantilism flourished saw the beginning of scientific analysis and measurement of population trends.26 The first of the writers to discern an underlying order in vital statistics was Graunt, who observed âthe numerical regularity of deaths and births, of the ratio of the sexes at death and birth, and of the proportions of deaths from certain causes to all deaths in successive years and in different areas; in general terms of the uniformity and predictability of many important biological phenomena in the massâ.27 Petty, more speculative than Graunt, stressed the advantages of a large population on fiscal, administrative, and economic grounds. He noted that, should the population double every 360 years, there would in 2,000 years be one person for e...