Thomas Malthus

Written by: Paul Thompson

Primary Source: Thornapple CSA

If Amartya Sen deserves to be called a food ethics icon for dismantling the idea that the total amount of food produced provides a good index for understanding the ethics of hunger, we should probably look the source of that idea for our next entry for “food ethics icons month”. Is there anyone out there who would not go back to Thomas Malthus for that idea? Haven’t all of us heard about “Malthusian” predictions and scenarios, after all?

As a teacher of undergraduates I am well aware of the fact that there are many of us who have never heard of Malthus, so please recognize the rhetorical nature of these last two questions. Thomas Robert Malthus lived from 1766 to 1834. He could be described as an economist, a philosopher, an applied mathematician and a political theorist. He started out by becoming ordained in the Church of England, which led to sobriquets acknowledging his religious affiliations throughout his lifetime and down to the present day. For most of his life he was actually a college professor. When I was a fairly young professor of philosophy and agricultural economics at Texas A&M University in the 1980s, I spent a good chunk of time not only reading up on Malthus, but actually reading him. Malthus wrote on the economic interpretation of rent, but I did not read any of that stuff. What I did read were several versions of his work on population. This was thirty years ago, so take what follows with a grain of salt.

Malthus was not the only person thinking about population when he proposed an early formula for what we now call “population ecology” in 1798. He wrote that while food production increases arithmeticaly, population grows geometrically. Therefore population eventually outstrips the food supply. If you do know Malthus, that’s probably what you know, but please pause and notice that this is a very obscure and abstract little formula. “Geometrical increase” was nicely explained in the Pete Seeger song “We’ll All Be a Doubling”:

Two times two is four!
Two times four is eight!
Two times eight is sixteen
And the hour is getting late!

We’ll all be a-doubling, a-doubling, a-doubling
We’ll all be a-doubling in thirty-two years.

You get the idea.

Malthus had combined a study of the facts with some fancy mathematical modeling to come up with this, but what he thought was important was that this is “the natural rate of increase” in population, not the actual rate of increase. In fact, something constrains the natural rate of increase, and the so-called arithmetical growth in food production was proposed as one basis of constraint. Unlike the careful science behind population, Malthus based his claims about agriculture on a thought experiment. Suppose that in the first generation we do “double” food production (I’m taking some liberties here because Malthus did not think even this possible). Surely next time around the best we can do is increase it by the same amount, but now that will only be a 50% increase over what he had. Next time around a similarly sized growth in total food production will only be a 25% increase, and so on. So we have a theoretical model which shows that the natural rates of growth of population and agriculture lead to the theoretical conclusion that population eventually outstrips food supply.

Present day population ecologists still take this model pretty seriously, though like Aldo Leopold, they are more likely to talk about deer than humans. If the population of deer are not “checked”, then they will eventually exhaust their food supply, leading to a catastrophic population crash. How is population growth checked? Well, if we are talking about deer, we look for wolves, and if none are to be found we rely on hunters. When we shift to the human population, these solutions have not been ethically popular. And this brings me to what I remember Malthus as actually saying, generally with increasing clarity as his work on population progressed over a period of nearly forty years. He wasn’t saying that agriculture was in a race with population. He was setting up a research problem: What does provide the checks on human population growth? His answer? It’s general poverty in the case of the poor. People die from sickness and overwork. And in the case of the rich? Here Malthus had to be circumspect. Rich families recognized good incentives to keep their families smaller than the “natural increase” would suggest. As someone who sent two kids through college, I understand these incentives. How did the rich act on those incentives? Malthus’ one word answer was “vice”, by which he meant frequenting prostitutes.

Who said that food ethics lacks a racy side?

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Paul Thompson
Paul B. Thompson holds the W. K. Kellogg Chair in Agricultural, Food and Community Ethics at Michigan State University in East Lansing, Michigan. He formerly held positions in philosophy at Texas A&M University and Purdue University. His research has centered on ethical and philosophical questions associated with agriculture and food, and especially concerning the guidance and development of agricultural technoscience.
Paul Thompson

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