Tragedy of the Commons

Saturday September 18, 2021

I was taught about the tragedy of the commons in my high school environmental science class. The day opened up with what is apparently a “classic” classroom activity for teaching this, involving goldfish crackers and straws:

Divide into groups of 4. Each group should sit in a circle around the “lake”. The goal of this activity is to see how each of you will behave when resources are not privately owned.

Each one of you represents the head of a family that is starving. In order for your family to survive, you must catch enough fish for them to eat. The only food source is a small local lake which can accommodate 16 fish. You must fish by sucking up the “fish” from the “lake” with straws.

You will get a chance to fish once a year (which lasts one minute) and each time you fish you may take 0, 1, 2, 3 or 4 fish from the lake. You should rotate your fishing order every year so that everyone has a chance to go first. It is your choice of how many fish you take, however, if you only take one fish, your family will be hungry. If you take more than 2 fish, you can sell them for a profit. The fish in your lake will reproduce once a year. [See your teacher at the end of each year - each remaining fish is able to spontaneously reproduce and make one new fish (4 fish become 8, i.e., to a maximum of 16)]. Keep the fish that you “catch” in front of you. You may eat the fish you keep for your family after each round. When your group runs out of fish, the game is over for you (put 0 fish in any remaining boxes in your table). Play a second game, then pick up reflection questions from your teacher.

Please do not talk or communicate while fishing!!

After the activity, the teacher gave an explanation of the tragedy of the commons — that resources that are collectively owned will be exploited, leading to depletion of resources and collapse. This can be applied to many things — overfishing, deforestation, pollution, CO₂ emissions, and more.

So, where does this idea come from? The term was coined in the eponymous 1968 paper “The Tragedy of the Commons” by white nationalist and eugenicist Garrett Hardin:

The tragedy of the commons develops in this way. Picture a pasture open to all. It is to be expected that each herdsman will try to keep as many cattle as possible on the commons. Such an arrangement may work reasonably satisfactorily for centuries because tribal wars, poaching, and disease keep the numbers of both man and beast well below the carrying capacity of the land. Finally, however, comes the day of reckoning, that is, the day when the long-desired goal of social stability becomes a reality. At this point, the inherent logic of the commons remorselessly generates tragedy.

[…]

[T]he rational herdsman concludes that the only sensible course for him to pursue is to add another animal to his herd. And another…. But this is the conclusion reached by each and every rational herdsman sharing a commons. Therein is the tragedy. Each man is locked into a system that compels him to increase his herd without limit — in a world that is limited. Ruin is the destination toward which all men rush, each pursuing his own best interest in a society that believes in the freedom of the commons. Freedom in a commons brings ruin to all.

This is a strange hypothetical for a case where ample historical evidence exists. There is wild diversity in how common pastures have been managed in different places and times. In the article No Tragedy on the Commons, Susan Jane Buck Cox describes pasture management in Medieval times:

Such agreements among the neighbors are recorded in the village bylaws. These bylaws “emphasize the degree to which… agricultural practice was directed and controlled by an assembly of cultivators, the manorial court, who coordinated and regulated the season-by-season activities of the whole community. Arable and meadowland were normally thrown open for common pasturing by the stock of all the commoners after harvest and in fallow times, and this necessitated some rules about cropping, fencing, and grazing beasts. Similarly, all the cultivators of the intermixed strips enjoyed common pasturage in the waste, and in addition, the rights to gather timber, peat and other commodities were essential concomitants of the possession of arable and meadow shares.” There was, however, an extraordinary diversity of bylaws among the various regions of England. In one Lincoln-shire fenland village, for example, “strangers coming into the town but having no land could enjoy free common for their cattle for one year. After that they had to abide by the rules governing all other inhabitants. These were generous provisions that reflected the abundance of grazing.” In contrast, in 1440, the village of Launton decreed that “any tenant who has a parcel of meadow in East Brokemede shall not mow there now or ever until his neighbors are agreed under pain of 3s.4d.,” a clear reflection of the need to conserve and to regulate. What is important to note here is the detail with which the open fields were regulated. Ault notes that bylaws covered such points as where field workers were paid (at the granary rather than in the field, where payment in kind might lead to accusations of theft) and at what age boys could begin to pasture sheep on the common (sixteen). The commons were carefully and painstakingly regulated, and those instances in which the common deteriorated were most often due to lawbreaking and to oppression of the poorer tenant rather than to egoistic abuse of a common resource.

This reality is quite different than the situation that Garrett Hardin seems to picture in his head. In fact, the reality is that exploitation of common pastures was more often driven by the rich, who could afford to keep many more cattle during the winter, when grazing was unavailable and animals needed to be fed grain. The details of any actual part of reality seem to impede Hardin’s point though, so he omits them and largely keeps to thought experiments instead.

The fact that many early English common grazing lands did not operate as Hardin assumed they did doesn’t make a general case either for or against the idea that the “Tragedy of the Commons” is useful general purpose tool. But before we examine that, it’s worth looking more at the context of the original paper. The concluding paragraphs of the paper read:

The most important aspect of necessity that we must now recognize, is the necessity of abandoning the commons in breeding. No technical solution can rescue us from the misery of overpopulation. Freedom to breed will bring ruin to all. At the moment, to avoid hard decisions many of us are tempted to propagandize for conscience and responsible parenthood. The temptation must be resisted, because an appeal to independently acting consciences selects for the disappearance of all conscience in the long run, and an increase in anxiety in the short.

The only way we can preserve and nurture other and more precious freedoms is by relinquishing the freedom to breed, and that very soon. “Freedom is the recognition of necessity” — and it is the role of education to reveal to all the necessity of abandoning the freedom to breed. Only so, can we put an end to this aspect of the tragedy of the commons.

Now, who does he think should be allowed to breed? We can look at other parts of the paper to get an idea:

With real estate and other material goods, the alternative we have chosen is the institution of private property coupled with legal inheritance. Is this system perfectly just? As a genetically trained biologist I deny that it is. It seems to me that, if there are to be differences in individual inheritance, legal possession should be perfectly correlated with biological inheritance — that those who are biologically more fit to be the custodians of property and power should legally inherit more.

Twenty-six years after publishing that, Hardin responded to criticisms which pointed out examples of commons which are well managed, in his 1994 paper “The Tragedy of the Unmanaged Commons.” In that paper, he still refrains from giving any positive examples, instead just talking about how most of the commons that people bring up as counterexamples are “managed” somehow, and thus exempt from the tragedy of the commons. He still has the eugenicist talking points:

‘To each according to his needs’ is an immensely seductive phrase to religious people, but in a world without national population controls it is a sure recipe for disaster. Those who are really concerned with the environment - concerned with the well-being of posterity - must give the carrying capacity of the environment precedence over discontinuous human needs, however much these needs may tug at our heartstrings.

So, after 26 years and countless papers refuting his original idea, what are we left with? The idea that an “unmanaged commons” will result in disaster (except in the cases that it doesn’t), used as a way to advocate preventing undesirables from breeding as an inevitable conclusion.

But do “unmanaged commons” really exist? Hardin presupposes that centralized ownership is a requirement for a commons to be “managed”, but provides no reason to think that’s true. He also dismisses lack of “management” (read: centralized management) as only working in small groups (less than 150 people, he claims, again with no evidence), but doesn’t stop to consider that not every commons needs to be used large numbers of people.

And yet, despite all that, we’re still teaching this in classrooms, telling ourselves that since high-school students sitting around a bowl of goldfish crackers, disallowed from communicating with each other, deplete their resources, the same principle must apply to all sorts of real-world scenarios.

Thinking about incentive structures, collective decisionmaking, and how to manage shared resources is certainly useful. The idea of “The Tragedy of the Commons,” however, doesn’t seem very useful — it was created as a piece of propaganda to advocate privatization and eugenics, and as such, was created in a context that was deeply uninterested in understanding the world or how to better manage the resources we’ve been given. The very idea of the tragedy of the commons presupposes that collective ownership will never work, when in reality, I suspect it’s perhaps the only thing that can get us out of the mess we’re in.