7.7: The Classical Dynamics of Malthus

Thomas Malthus had a serious view of how economies grow. He believed that while people hope for progress, it may not last. The main reason is that the population can grow faster than the food supply. When this happens, living standards fall, and people struggle to survive.

Think of a quiet farming town where land is rich and families are small. At first, food is enough, and workers earn decent wages. But over time, families grow, and more children are born. Fields don’t expand, and crops don’t increase fast enough to keep up. More people have to share the same land. Each new worker adds less to the harvest than the one before. Slowly, output per person starts to fall.

This idea—where adding more people leads to smaller gains—is known as diminishing returns. It means there’s a point where doing more doesn’t help as much as before. As food becomes harder to get, wages fall. People can’t afford to live well. Malthus believed that when things get too bad, natural events like disease or hunger would reduce the population. It’s not a choice but a lot of pressure.

Even if there is some improvement, like better harvests or higher pay, the cycle often starts again. A better life leads to more births, and soon, resources are stretched thin again. Malthus called this pattern a trap because it repeats over time. It shows how hard it can be to break free from poverty when population growth outpaces the food supply.

In 1798, Thomas Robert Malthus published his Essay on the Principle of Population, offering a more pessimistic view of economic growth.

Imagine a small farming village where land is initially plentiful. Farmers grow enough food, and real wages are relatively high.

But as families grow, the population increases steadily. Malthus argued that the population grows geometrically—1, 2, 4, 8, 16—while the food supply grows only arithmetically—1, 3, 5, 7, 9.

Over time, land becomes scarce. As more people share the same plots, productivity declines. This reflects the law of diminishing returns—each additional farmer adds less output than the one before. This leads to hunger, poverty, and overcrowding.

Malthus believed these pressures would lead to natural checks like famine, disease, and death, restoring the population to subsistence levels.

At this point, real wages stay low, barely enough to live. Any progress is temporary, as population growth cancels it out, trapping the economy in the Malthusian trap.