The Tragedy of the Commons

The population problem has no technical solution; it requires a fundamental extension in morality.

Garrett Hardin


The original is available at:


I have cut, edited and rearranged the original here.  My intent was not to change the meaning but to condense it.  The comments, in this font, and the italics are mine.  Michael Dixon



An article on the future of nuclear war, concluded that: "Both sides in the arms race are ... confronted by the dilemma of steadily increasing military power and steadily decreasing national security. It is our considered professional judgment that this dilemma has no technical solution. If the great powers continue to look for solutions in the area of science and technology only, the result will be to worsen the situation."  Science almost always assumes that problems have technical solutions. A technical solution may be defined as one that requires a change only in the techniques of the natural sciences, demanding little or nothing in the way of change in human values or ideas of morality.  We expect, and welcome, technical solutions. But Garrett Hardin, wanted us to know that there are human problems that have no technical solutions.


Hardin wanted to address the "population problem".  Others want or hope to avoid the problems 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. He wants us to understand that the human population problem cannot be solved by technology.


What Shall We Maximize?

We live in a world with limited resources.  The more people, the less resources there are for each individual. Malthus taught us that populations grow exponentially. So we should expect more people without getting enough resources for them.


A limited world can support only a limited population.  When we reach the maximum number of people that can survive on the planet what condition will we be in?  Can we have "the greatest good for the greatest number of people?


No--for two reasons.


The first is a theoretical one. It is not mathematically possible to maximize two variables at the same time. It is impossible to have the maximum number of people and the maximum amount of resources for each person. (Example: If I had $1000 to give to charity, I could give all of it to the Red Cross or I could give $500 to both Red Cross and the American Cancer Society but it is impossible to give $1000 to both of them.  I will have to make some compromise.)


The second reason springs directly from biology. To live we need energy (for example, the calories in food). This energy is used for two purposes: maintenance and work. Maintenance is just keeping our bodies alive. Work calories, as he uses the term, are for everything else: “work” plus all forms of enjoyment, from swimming and automobile racing to playing music and writing poetry: anything beyond just maintaining your existence.


As human population increases there must be more calories available for the maintenance of all these people.  To provide this energy we will have to decrease the “work” calories used by each person. No gourmet meals, no vacations, no sports, no music, no literature, no art. ... I think that everyone will grant, that maximizing population does not maximize good.


The optimum population, if we want any of life’s extras, is less than the maximum.


We want the maximum good per person; but what is good? To one person it is wilderness, to another it is ski lodges for thousands.  The same area cannot please both. To one it is estuaries to nourish ducks for hunters to shoot; to another it is factory land. How can we balance what everyone desires?


Adam Smith in The Wealth of Nations (1776) popularized the idea of an "invisible hand," that when an individual who "intends only his own gain," is "led by an invisible hand to promote . . . the public interest."  This contributed to the dominant thought that decisions reached individually will, in fact, be the best decisions for an entire society.  If this assumption is correct, we can assume that humans will control their reproduction to produce the optimum population. If the assumption is not correct, we need to reexamine our individual freedoms to see which ones are defensible.


Tragedy of Freedom in a Commons

The argument against the “invisible hand” in population control was first written in 1833 by William Forster Lloyd (1794-1852).


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 well for centuries because tribal wars, poaching, and disease keep the numbers of both man and beast well below what the land can support. 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.


As a rational being, each herdsman wants to maximize his gain.  He receives all the proceeds from the sale of every additional animal he keeps.  Keeping more animals provides a benefit.  However, each additional animal competes for food and contributes to overgrazing. This negative affects all of the animals and is shared by all the herdsmen.


A rational herdsman concludes that the only sensible course for him to pursue is to add another animal to his herd. And another; 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.


The logic of the commons has been understood for a long time but continues to be a problem.  Some examples:


Pollution works in a similar way. The rational man finds that the disadvantage of dumping wastes is less than the cost of cleaning them up. Since this is true for everyone, we are locked into a system of "fouling our own nest," so long as we behave only as independent, rational, free-enterprisers.


We use laws and taxes and try to stem this pollution but the owner of a factory or farm on the bank of a stream--whose property extends to the middle of the stream, often has difficulty seeing why it is not his natural right to muddy the waters flowing past his door.


The pollution problem is a consequence of population. It did not much matter how a lonely American frontiersman disposed of his waste. "Flowing water purifies itself every 10 miles," my grandfather used to say, and the myth was near enough to the truth when he was a boy, for there were not too many people. But as population became denser, the natural chemical and biological recycling processes became overloaded, calling for a redefinition of property rights.


How To Legislate Temperance?


Some morality, such as "Thou shalt not . . ." makes no allowance for particular circumstances. But a generally principle of morality is that the circumstances are important. Using the commons as a cesspool does not harm the general public under frontier conditions, because there is no public, the same behavior in a metropolis is unbearable. A hundred and fifty years ago a plainsman could kill an American bison, cut out only the tongue for his dinner, and discard the rest of the animal. He was not in any important sense being wasteful. Today we would be appalled at such behavior.


Prohibition is easy to legislate (though not necessarily to enforce); but how do we legislate moderation?


Freedom To Breed Is Intolerable


In a world governed solely by the principle of "dog eat dog," how many children a family had would not be a matter of public concern. Most parents who bred too exuberantly would leave fewer descendants, not more, because they would be unable to care adequately for their children. This idea has been shown to be true in some animals but humans have not acted this way for thousands of years.


If each human family were dependent only on its own resources; if the children of improvident parents starved to death; if, thus, overbreeding brought its own "punishment" to the germ line--then there would be no public interest in controlling the breeding of families. But our society is deeply committed to the welfare state, and hence is confronted with another aspect of the tragedy of the commons.


In a welfare state, how shall we deal with the family, the religion, the race, or the class that adopts overbreeding as a policy to secure its own aggrandizement? To couple the concept of freedom to breed with the belief that everyone born has an equal right to the commons is to lock the world into a tragic course of action.


Unfortunately this is just the course of action that is being pursued by the United Nations. In late 1967, some 30 nations agreed to the following:


    The Universal Declaration of Human Rights describes the family as the natural and fundamental unit of society. It follows that any choice and decision with regard to the size of the family must irrevocably rest with the family itself, and cannot be made by anyone else. (Today it is International Law.)


It is painful to have to deny categorically the validity of this right.


Conscience Is Self-Eliminating

It is a mistake to think that we can control the breeding of mankind in the long run by an appeal to conscience. People vary. Confronted with appeals to limit breeding, some people will undoubtedly respond to the plea more than others. Those who have more children will produce a larger fraction of the next generation than those with more susceptible consciences. The difference will be accentuated, generation by generation.


In C. G. Darwin's words (the famous Darwin’s grandson): "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".


Mutual Coercion Mutually Agreed upon

The social arrangements that produce responsibility are coercion, of a sort. Consider bank-robbing. The man who takes money from a bank acts as if the bank were a commons. How do we prevent such action? Certainly not by asking “Please don’t rob banks”.  We have made laws. It does not bother us that we infringe on the freedom of robbers.


The morality of bank-robbing is particularly easy to understand because we accept complete prohibition of this activity. We are willing to say "Thou shalt not rob banks," without providing for exceptions. But temperance also can be created by coercion.  To keep downtown shoppers from monopolizing parking space we introduce parking meters for short periods, and traffic fines for longer ones. We need not actually forbid a citizen to park as long as he wants to; we need merely make it increasingly expensive for him to do so. Not prohibition, but carefully biased options are what we offer him.


To say that we mutually agree to coercion is not to say that we are required to enjoy it, or even to pretend we enjoy it. Who enjoys taxes? We all grumble about them. But we accept compulsory taxes because we recognize that voluntary taxes would favor the conscienceless. We institute and (grumblingly) support taxes and other coercive devices to escape the horror of the commons.


We must make a choice.  Keeping the status quo is an action, with advantages and disadvantages, which we must compare with the predicted advantages and disadvantages of any proposed reform.


Recognition of Necessity

Perhaps the simplest summary of this analysis of man's population problems is this: the commons, if justifiable at all, is justifiable only under conditions of low-population density. As the human population has increased, the commons has had to be abandoned in one aspect after another.


First we abandoned the commons in food gathering, enclosing farm land and restricting pastures and hunting and fishing areas. These restrictions are still not complete throughout the world.


Somewhat later we saw that the commons as a place for waste disposal would also have to be abandoned. Restrictions on the disposal of domestic sewage are widely accepted in the Western world; we are still struggling to close the commons to pollution by automobiles, factories, insecticide sprayers, fertilizing operations, and atomic energy installations.


Every new enclosure of the commons involves the infringement of somebody's personal liberty. Infringements made in the distant past are accepted because no contemporary complains of a loss. It is the newly proposed infringements that we vigorously oppose; cries of "rights" and "freedom" fill the air. But what does "freedom" mean? When men mutually agreed to pass laws against robbing, mankind became more free, not less so.


We must now recognize 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.


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.