Thomas Malthus was one of the most influential thinkers of all time. His father knew Hume and Rousseau, and his own paper–An Essay on the Principle of Population–forever changed the way we think about populations and food supplies. It has informed food security policies worldwide, and provided the basic underpinnings of our modern concern with overpopulation. In The Origin of Species, Darwin called his theory of natural selection an application of the doctrines of Malthus in an area without the complicating factor of human intelligence. Yes, Malthus’ work has been a major underpinning and influence on everything since. It’s a shame he was so incredibly wrong.

Malthus’ case is simple: population grows “geometrically” (exponentially), but food supply only grows arithmetically. So Malthus warned of a coming crisis where we would not be able to feed our burgeoning population–the “Malthusian catastrophe.” Of course, the failure of such a catastrophe to come to pass took a lot of wind out of Malthus’ sails. Malthusianism was declared dead after the 1960s and 1970s saw the greatest increases in human population ever seen, accompanied with higher calories per capita, thanks to the abundance of the Green Revolution. Cornucopians rejoiced as they saw the evidence come in that increasing population meant increasing prosperity for all: the realization of Jeremy Bentham’s credo, “the greatest good for the greatest number.”

If it seems too good to be true, that’s because it is. Even Bentham knew that the two factors needed to be balanced against one another, and that increasing one necessarily meant decreasing the other. As Garrett Hardin refuted it in his classic article, “The Tragedy of the Commons“:

A finite world can support only a finite population; therefore, population growth must eventually equal zero. (The case of perpetual wide fluctuations above and below zero is a trivial variant that need not be discussed.) When this condition is met, what will be the situation of mankind? Specifically, can Bentham’s goal of “the greatest good for the greatest number” be realized?

No — for two reasons, each sufficient by itself. The first is a theoretical one. It is not mathematically possible to maximize for two (or more) variables at the same time. This was clearly stated by von Neumann and Morgenstern, [3] but the principle is implicit in the theory of partial differential equations, dating back at least to D’Alembert (1717-1783).

The second reason springs directly from biological facts. To live, any organism must have a source of energy (for example, food). This energy is utilized for two purposes: mere maintenance and work. For man maintenance of life requires about 1600 kilocalories a day (”maintenance calories”). Anything that he does over and above merely staying alive will be defined as work, and is supported by “work calories” which he takes in. Work calories are used not only for what we call work in common speech; they are also required for all forms of enjoyment, from swimming and automobile racing to playing music and writing poetry. If our goal is to maximize population it is obvious what we must do: We must make the work calories per person approach as close to zero as possible. No gourmet meals, no vacations, no sports, no music, no literature, no art…I think that everyone will grant, without argument or proof, that maximizing population does not maximize goods. Bentham’s goal is impossible.

So why were the Cornucopians so right, and Malthus so wrong? Because Malthus got the entire problem almost completely backwards–and it has remained backwards ever since.

Science has never been as unbiased as it would like to be–how could it? Skewing results is easily noticed, and rightfully condemned–as happened with such forgeries as Piltdown Man. Much more insidious is a lack of curiousity. We do not question recieved wisdom, and what we do not question we cannot understand. From Genesis 1:28 to the present day, we’ve viewed population growth as an inherent property of human nature. It has gone unquestioned. Certainly an Anglican country parson like Malthus would not question it. Malthus’ problem was how to feed so many people–a problem that could only be solved by misery, vice (i.e., contraception) or moral restraint (i.e., abstinence). The country parson, naturally, favored the same kind of abstinence programs in favor by the United States’ current conservative regime.

This is entirely backwards. What are all these people made of, fairy dust and happy thoughts? No, they are made of proteins–of food! Without a sufficient food supply, such a population cannot be achieved. We understand this as a basic biological fact for every other species on this planet, that population is a function of food supply. Yet we continue to believe that the magic of free will exempts us from such basic biological laws.

The usual counter-argument goes something like this: Humans are different from other animals. We can think. We can rationally observe the situation, and decide for ourselves how many children to have. While this is certainly true of individuals, groups are governed by much more deterministic criteria. For every individual who decides to be responsible and only have 2.1 children, another will take advantage of the space that individual has opened by having seven. The variation in values, thought patterns, beliefs and feelings of social responsibility ensure that the reproductivity rates of a group will rise to the carrying capacity possible, regardless of the intelligent, responsible choices of others in the community. Charles Galton Darwin, the grandson of that Charles Darwin, said, “It may well be that it would take hundreds of generations for the progenitive instinct to develop in this way, but if it should do so, nature would have taken her revenge, and the variety Homo contracipiens would become extinct and would be replaced by the variety Homo progenitivus.”

Education is often proposed as a solution, but Garrett Hardin already offered the best counter-argument to that strategy, again in “The Tragedy of the Commons”:

The long-term disadvantage of an appeal to conscience should be enough to condemn it; but it has serious short-term disadvantages as well. If we ask a man who is exploiting a commons to desist “in the name of conscience,” what are we saying to him? What does he hear? — not only at the moment but also in the wee small hours of the night when, half asleep, he remembers not merely the words we used but also the nonverbal communication cues we gave him unawares? Sooner or later, consciously or subconsciously, he senses that he has received two communications, and that they are contradictory: 1. (intended communication) “If you don’t do as we ask, we will openly condemn you for not acting like a responsible citizen”; 2. (the unintended communication) “If you do behave as we ask, we will secretly condemn you for a simpleton who can be shamed into standing aside while the rest of us exploit the commons.”

Every man then is caught in what Bateson has called a “double bind.” Bateson and his co-workers have made a plausible case for viewing the double bind as an important causative factor in the genesis of schizophrenia. The double bind may not always be so damaging, but it always endangers the mental health of anyone to whom it is applied. “A bad conscience,” said Nietzsche, “is a kind of illness.”

All of this, however, is theoretical. This hypothesis is easy to test: calculate carrying capacity, and compare it to actual human population numbers. This is precisely what Russell Hopfenberg of Duke University did in his 2003 study, “Human Carrying Capacity is Determined by Food Availability.” [PDF] As you might imagine from such a title, he found that the numbers lined up almost perfectly.

There is a significant complication in this, however, which critics of this stance are eager to point out. The First World is facing a population growth decline–the world’s richest nations are growing by the smallest percentages. Italy has been very concerned with its low growth rate, only 0.11% according to a 2003 estimate. Italy has the 201st highest population growth, and the 100th highest agricultural growth. Meanwhile, Singapore has the sixth highest population growth rate, and the 147th highest agricultural growth rate–out of 147.

If population is a function of food supply, why is the most significant growth taking place in those areas producing the least food?

The answer, I think, lies in globalization. How much of what you ate today came from your own bioregion? Unless you do a significant amount of your grocery shopping at Farmers’ Markets or eat only USDA-certified organic food, probably not a lot. Interestingly, those same countries which produce so much food but don’t see it translate into their population, are also the heaviest exporters, and the impoverished countries with significantly rising growth rates are often the recipients. When the First World rushes in with foreign aid, food, and humanitarian aid to a desert area in the midst of a famine, we serve to prop up an unsustainable population. That drives a population boom in an area that already cannot support its existing population. The result is a huge population dependent on outside intervention that itself cannot be indefinitely sustained. Eventually, that population will crash once outside help is no longer possible–and the years of aid will only make that crash even more severe. In the same way that the United States’ policy of putting out all fires in the 1980s led to an even worse situation in its forests, our benevolence and good intentions have paved the way to a Malthusian hell.

Another part of the answer lies in our ecological footprint. While it is certainly true that population is a function of food supply, standard of living is an important factor in that equation. Not only how much food is available, but how much food each individual demands. The dwindling First World has the largest ecological footprint; the growing Third World has the smallest. Italy comes in at #25 with 5.51 hectares per person (1996); Somalia is #114 with 0.97.

Intelligence does not exempt us from basic biological laws–just as it has not exempted dolphins, crows or chimpanzees. Groups reproduce to the best of their ability, and the carrying capacity–their food supply–creates the ceiling of that ability. Populations will rise to their carrying capacity, and no further–even human populations. So Malthus has the problem entirely backwards. The problem is not how to feed so many people; of course we have the means to feed them, because if we didn’t, the population would not exist. The problem is the implications of so many people….

To support a population of 6.4 billion (as of this writing), the human species currently consumes roughly 40% of the earth’s photosynthetic capacity. The energy available to the earth per any given unit of time is finite, confined primarily to the amount of energy we recieve from the sun. That amount is called our photosynthetic capacity–it is, basically, all the energy in the world. 40% of it is tied up in a single species. Much more than we ourselves consume is what is consumed by our domesticates–our crops and livestock. Every time we clear new cropland, we effectively convert its existing biomass into human flesh, and no part of the conversion is perfect. The clearing itself loses the majority of that energy potential, and now the photosynthetic capacity of that land is going directly and solely to humans, rather than supporting the diversity of its pre-existing ecosystem. Plants do not use every bit of solar energy in photosynthesis, and if the crops are then fed to livestock there is another imperfect conversion. What we eat ourselves is not perfectly converted, so that the final amount of energy and nutrients we recieve is only a very small portion of the total energy involved–all without even mentioning the gross inefficiencies of oil-based agriculture since the Green Revolution.

This monopoly on the earth’s resources is having a devastating effect. We are seeing the extinction of some 140 species every day, some thousands of times higher than the normal background rate. Today, right now, we are seeing extinction rates at the second highest in the history of the earth. We are undeniably in the midst of the seventh mass extinction event in the history of the earth–the Holocene Extinction. Unlikely previous extinction events, however, this one is driven by a single species.

This is the true danger of overpopulation, not our inability to feed a growing population. As much as we would deny it, we depend on the earth to live. Dwindling biodiversity threatens the very survival of our species. We are literally cutting the ground out from under our feet.

Increasing food production only increases the population; our current attitudes about food security has locked us into what Daniel Quinn called a “Food Race,” by comparison to the Arms Race of the Cold War. Garrett Hardin began his famous article with this dilemna, and I’ll close with his assessment:

In our day (though not in earlier times) technical solutions are always welcome. Because of previous failures in prophecy, it takes courage to assert that a desired technical solution is not possible. Wiesner and York exhibited this courage; publishing in a science journal, they insisted that the solution to the problem was not to be found in the natural sciences. They cautiously qualified their statement with the phrase, “It is our considered professional judgment….” Whether they were right or not is not the concern of the present article. Rather, the concern here is with the important concept of a class of human problems which can be called “no technical solution problems,” and more specifically, with the identification and discussion of one of these.

It is easy to show that the class is not a null class. Recall the game of tick-tack-toe. Consider the problem, “How can I win the game of tick-tack-toe?” It is well known that I cannot, if I assume (in keeping with the conventions of game theory) that my opponent understands the game perfectly. Put another way, there is no “technical solution” to the problem. I can win only by giving a radical meaning to the word “win.” I can hit my opponent over the head; or I can falsify the records. Every way in which I “win” involves, in some sense, an abandonment of the game, as we intuitively understand it. (I can also, of course, openly abandon the game — refuse to play it. This is what most adults do.)

The class of “no technical solution problems” has members. My thesis is that the “population problem,” as conventionally conceived, is a member of this class. How it is conventionally conceived needs some comment. It is fair to say that most people who anguish over the population problem are trying to find a way to avoid the evils of overpopulation without relinquishing any of the privileges they now enjoy. They think that farming the seas or developing new strains of wheat will solve the problem — technologically. I try to show here that the solution they seek cannot be found. The population problem cannot be solved in a technical way, any more than can the problem of winning the game of tick-tack-toe.