Malthusian Theory

The principle of population

The English clergyman and economist Thomas Malthus published An Essay on the Principle of Population anonymously in 1798 to rebut the doctrines of unlimited human progress advanced by Godwin and Condorcet. He began from two postulates: food is necessary to human existence, and the passion between the sexes will remain nearly as it is. Population, when unchecked, doubles every twenty-five years, increasing geometrically (1, 2, 4, 8, 16), while food can at best increase arithmetically (1, 2, 3, 4, 5), because land is fixed and diminishing returns set in. Population therefore always presses against the limits of subsistence; even if wages rise temporarily, population grows until they return to subsistence. This logic shaped Ricardo's (1817) theory of rent and the subsistence theory of wages and helped earn economics the label "the dismal science."

Checks and the Malthusian trap

Malthus divided the checks that hold population to the food supply into two kinds. Positive checks raise mortality: famine, disease, war and infant death. Preventive checks lower fertility, for instance by delaying marriage. In the 1803 edition he emphasized moral restraint, late marriage and abstinence, conceding that humanity might avoid catastrophe. He also criticized the Poor Laws for encouraging births among the poor and so worsening poverty. His account of the struggle for existence gave Charles Darwin (1859) decisive inspiration for the theory of natural selection. Economic historian Gregory Clark (2007) argued that for millennia before 1800, gains from technology were absorbed by population growth so that income per person barely rose, and that this Malthusian trap explains the preindustrial world well. Ashraf and Galor (2011) found empirical evidence that technology raised population density rather than income per person.

Rebuttals and modern assessment

After the Industrial Revolution, technological progress and falling fertility let income per person rise persistently, and Malthus's forecast failed. Ester Boserup (1965) countered that population pressure stimulates agricultural innovation, and Michael Kremer (1993) modeled how a larger population means more people producing ideas and faster technological progress. Neo-Malthusians nonetheless warned of resource depletion and environmental crisis, notably Paul Ehrlich's The Population Bomb (1968) and the Club of Rome's The Limits to Growth (1972). Julian Simon (1981) replied that human ingenuity is the ultimate resource, and won his 1980 commodity-price wager with Ehrlich. Oded Galor and David Weil's (2000) unified growth theory explains in one model the Malthusian stagnation, a transition in which technological progress raises demand for human capital, and the demographic transition with sustained growth, reinterpreting Malthus as the first stage of the history of growth (Galor, 2011).

FAQ

What is Malthusian theory in simple terms?

Population grows fast, like 2, 4, 8, while food grows slowly, like 1, 2, 3, so famine or disease eventually cuts population and people stay barely above subsistence.

Why did Malthus's prediction fail?

After the Industrial Revolution, technology made food and output grow faster than population, and the demographic transition lowered fertility, so income per person rose steadily.

Sources reviewed: 2026-10-26

References

1. Malthus, T. R. (1798). An Essay on the Principle of Population. London: J. Johnson.
2. Malthus, T. R. (1803). An Essay on the Principle of Population (2nd ed.). London: J. Johnson.
3. Ricardo, D. (1817). On the Principles of Political Economy and Taxation. London: John Murray.
4. Darwin, C. (1859). On the Origin of Species. London: John Murray.
5. Boserup, E. (1965). The Conditions of Agricultural Growth. London: Allen & Unwin.
6. Ehrlich, P. R. (1968). The Population Bomb. New York: Ballantine Books.
7. Meadows, D. H., Meadows, D. L., Randers, J., & Behrens, W. W. (1972). The Limits to Growth. New York: Universe Books.
8. Simon, J. L. (1981). The Ultimate Resource. Princeton: Princeton University Press.
9. Galor, O., & Weil, D. N. (2000). Population, technology, and growth: From Malthusian stagnation to the demographic transition and beyond. American Economic Review, 90(4), 806–828.
10. Clark, G. (2007). A Farewell to Alms: A Brief Economic History of the World. Princeton: Princeton University Press.
11. Ashraf, Q., & Galor, O. (2011). Dynamics and stagnation in the Malthusian epoch. American Economic Review, 101(5), 2003–2041.
12. Kremer, M. (1993). Population growth and technological change: One million B.C. to 1990. Quarterly Journal of Economics, 108(3), 681–716.
13. Galor, O. (2011). Unified Growth Theory. Princeton: Princeton University Press.