What Is Garrett Hardin's Simple Mathematical Argument for the Inevitability of “Tragedy of the Commons"?
Since that time, the idea of the tragedy of the commons has been a central part of population theory. Many people insist that the logic of the commons is irrefutable; others argue that the logic is flawed and the premises questionable. Despite debates over its validity, the theory of the commons has become an important part of modern efforts to understand and project population growth.
Hardin rejected the wild hope that improved food production technology will allow an indefinite increase in population: "a finite world can support only a finite population." More specifically, we cannot hope to provide growth in both the material quality of life and population. Mathematically, both factors cannot be maximized at once; and biophysically, the calories available per person must decrease as population increases. Thus he invalidated Jeremy Bentham's goal of "the greatest good for the greatest number," and concluded "the optimum population is, then, less than the maximum." (Notably, also according to this logic, the strategy of decreasing population by increasing the "standard of living" (consumption), as predicted by the demographic transition model, might be reexamined.) But we have difficulty choosing to limit population, and choosing between which goods to pursue in a world that cannot provide for every different good because we have left the choice of "the good" entirely to individuals in our capitalistic society. We act as if individual choices will somehow solve collective problems such as population. Adam Smith's laissez-faire doctrine of the invisible hand tempts us to think that a system of individuals pursuing their private interests will automatically serve the collective interest. But applying this would be disastrous. Hardin employed a key metaphor, the Tragedy of the Commons (ToC) to show why. When a resource is held "in common," with many people having "ownership" and access to it, Hardin reasoned, a self-interested "rational" actor will decide to increase his or her exploitation of the resource since he or she receives the full benefit of the increase, but the costs are spread among all users. The remorseless and tragic result of each person thinking this way, however, is ruin of the commons, and thus of everyone using it. The straightforward application of the "herdsman" analogy to world population is that each couple expects to experience a large benefit from having another child, but only a little of the full social and ecological cost. Both Hardin's solutions, and their weaknesses, stem from things assumed in this model. His basic solution is that we must abandon the commons system in breeding (as we have already in food production and pollution - instances where we have used privatization and laws to achieve this). People must no longer be free to add unlimited numbers of offspring to the total load on the earth's ecosystems. This sounds simple enough, but the key question is how this restriction is to be achieved. Hardin's rejection of some solutions stems from the individualistic assumptions of his metaphor. Particularly, he rejects appeals to conscience, because they would "select for" those without scruples over having more children. It is doubtful however that conscience is entirely genetic, nor perfectly transmitted by learning in families. Further, his assumption that were it not for "welfare," over-breeders would have to pay for their profligacy, runs in the face of evidence that parents whose infants die are paradoxically both more inclined to get pregnant again, and less likely to emotionally invest in their young. Welfare may indeed be part of solving the population problem. This is just one example where Hardin fails to differentiate reproductive behavior according to socio-economic conditions.
Freedom in a commons brings ruin to all.” It has proved to be a powerful idea. To Hardin and others, the same grim logic was behind many of our biggest problems. Common resources, such as fisheries, forests, and even the air are threatened by selfish individuals and nations taking what they can, even though they know the resource will be wiped out if everyone does the same. Hardin’s solution was to cede our freedoms to the state, to be bound by “mutual coercion mutually agreed upon”. This brand of tragedy is particularly urgent today as our population and technology put more and more strain on limited nature. On the global stage, the greatest tragedy of the commons is climate change. Despite knowing of this looming threat, countries have delayed taking real action for decades, quarreling over costs and responsibility, failing to build trust, all the while continuing to pour greenhouse gases into the atmosphere. Even in the wake of the Paris Agreement, the 2016 United States election has placed the status of a major player in doubt. Lacking any higher authority to rein in the selfishness of nations, are we doomed? Maybe not. As later researchers pointed out, the picture is more complicated than Hardin allowed. Although some resources are abused, others are often managed well without state intervention. Recent interdisciplinary work offers hope that the tragedy is not so inevitable after all. Instead, governments and institutions can design systems to help people control their selfish impulses, join collective schemes, and protect endangered resources. The global stage is more troublesome, but insights from game theory point to a possible way out of the climate change coma and other seemingly tragic situations: We just need to change the game that nations play (Ostrom E., 1990).
Fishes that aggregate to spawn in highly predictable parts of the environment are most susceptible, and regulations to protect spawning fishes can be useful.
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Ostrom E (1990) Governing the Commons: The Evolution of Institutions for Collective Action (Cambridge Univ Press, Cambridge, UK).
Tang S (1994) in Rules, Games, & Common-Pool Resources, eds Ostrom E, Gardner R, Walker J (Univ of Michigan Press, Ann Arbor, MI), pp 225–246
Agrawal A, Ostrom E (2001) Collective action, property rights, and decentralization in resource use in India and Nepal. Polit Soc 29:485–514.
Yang W, et al. (2013) Nonlinear effects of group size on collective action and resource outcomes. Proc Natl Acad Sci USA 110(27):10916–10921.