ABSTRACT
The size of the human population of the earth and its impact on the quality of human life has been a recurring theme of anxiety and discussion in the last half-century. Much of this discussion is based on two premises: that the size of the earth’s population is an important factor in determining the quality of life, because the planet’s resources, surface, and environment have a limited capacity to support human life; and that the population will tend to grow uncontrollablywithout some type of intervention. This type of thinking leads to popular doomsday scenarios in which overpopulation destroys the quality of life. It also supports a kind of population determinism, which sees the absolute size of the world’s population as the main determinant of world economicwelfare. (Much of this chapter has been published as Foley, 2000b. The idea that increasing returns might stabilize human populations arose during the visit of David Colander to my undergraduate Political Economy class at Barnard College. I am indebted to Adalmir Marquetti for his help in collecting the data.) These ideas have a close relation to Classical political economy, partic-
ularly to the views of Malthus and Ricardo on population and diminishing returns. Their sudden vogue after the Second World War arose because the secondhalf of the twentieth century did indeed see an explosion inworld population, coinciding with the extension of European and American capitalist institutions, infrastructure, and medical care to the greater part of the world. I tend to accept the first premise of this discussion. The size of the human
population probably does have a substantial impact on the quality of life. But for the levels of world population we have historically experienced and are likely ever to reach, the larger the population the better the quality of life
tends to be. I tend, on the other hand, to doubt the second premise. A correct application of Classical political economy methods to the problem of determining the world equilibrium of population predicts a stabilization of population at a relatively high per-capita income, and far from the diminishing returns at the heart of Malthus’ and Ricardo’s vision. I suspect that world population will stabilize somewhere around 20-40 percent above its current level of six billion, that is, in the range of seven to eight and a half billion people, with world per capita income about 20-40 percent higher than it was in 1990. This is a large, but manageable, population. The population problems of the twenty-first century are likely to be quite different from those of the last half of the twentieth century. Stable populations have an age structure with a much higher proportion of older, retired, and therefore not economically active people. Furthermore, it is likely that the stabilization of total world population and incomewill come about through a sharp polarization between countries with rich aging populations which cannot reproduce themselves and countrieswith poor, younger populationswhich are growing.
Smith and Malthus The Classical political economists regarded the problem of population as an aspect of the analysis of capital accumulation and growth. In this view, population growth is a consequence of economic development, and the size of the population is regulated by economic factors. Malthus based his analysis on two central postulates: that increasing
standards of living raise net population growth rates by reducing mortality (particularly infant mortality) and raising fertility, and that the standard of living is regulated by diminishing returns to human productive activity in the face of limited land, including natural resources. The implication of these two postulates is Malthus’ famous, frightening, image of a stable demographic equilibrium at which high mortality balances high fertility at a low absolute average standard of living. Increases in natural resources and labor productivity, in Malthus’ framework, raise the equilibrium level of population without much altering its low standard of living. Despite a widespread recognition that this is not really how the modern world economy works, this Malthusian nightmare continues to lurk behind the discussion of population questions. History has not borne out Malthus’ postulates. While the early stages
of economic growth did indeed produce population explosions in many
