In brief
A commons is a resource that a community uses and cares for together under its own rules, such as a pasture, a forest, water, seed or knowledge.
What a commons is
A commons is more than a thing that belongs to nobody. It has three parts. The first is a resource: a pasture, a forest, a fishing ground, a spring, seed or knowledge. The second is a community that uses it. The third is the set of rules by which that community takes from the resource, cares for it and settles its disputes. Economists call the resource itself a common-pool resource. What turns it into a commons is the third part, the shared rules.
This distinction matters. A meadow that anyone may use without any agreement is not a commons in this sense but open access. For a long time the two were confused, and the confusion shaped half a century of debate about land, water and fishing grounds.
The tragedy of the commons
In December 1968 the American biologist Garrett Hardin published an essay in the journal Science titled "The Tragedy of the Commons". He imagined a pasture open to all. Each herder gains the full benefit of adding one more animal, while the cost of overgrazing is shared by everyone. Acting rationally, each keeps adding animals until the pasture is ruined. Hardin put it in one sentence: "Freedom in a commons brings ruin to all." His real concern was population growth, and as remedies he saw private property or regulation by the state.
The essay became one of the most cited texts of the environmental debate, and its title passed into everyday language. It also carried a gap. Hardin's pasture has users but no community, no rules and no one who watches over it. It describes open access, not a commons as the people who run one know it. Hardin conceded the point himself. In a letter to Science in 1998 he called the omission of the word "unmanaged" the weightiest mistake of his essay.
Elinor Ostrom's counter-evidence
The political scientist Elinor Ostrom of Indiana University went looking for the commons that had not collapsed. In Governing the Commons (1990) she compared cases from around the world in which users had managed shared pastures, forests, fisheries and irrigation systems over long periods, without privatising them and without handing them to the state. Among them are the alpine pastures and forests of Törbel in the Swiss canton of Valais, the common mountain lands of the Japanese villages Hirano, Nagaike and Yamanoka, and the irrigation communities of the Spanish huertas around Valencia, Murcia and Alicante.
The huerta of Valencia shows how lasting such rules can be. Disputes over water are still brought before the Water Tribunal, which meets every Thursday at the Apostles' Door of the cathedral. Its members are farmers elected by the irrigation communities, and its judgments are given orally and at once. In 2009 UNESCO inscribed it, together with the Council of Wise Men of the plain of Murcia, on the Representative List of the Intangible Cultural Heritage of Humanity and traced both tribunals back to the time of al-Andalus.
From such cases Ostrom drew eight design principles that long-lived commons share. In our words:
- Clear boundaries. It is clear who may use the resource and where it ends.
- Rules that fit the place. What users may take and what they must contribute suit local conditions and stand in proportion to each other.
- A say for those affected. Most of those bound by the rules can take part in changing them.
- Monitoring. Someone watches the state of the resource and the conduct of its users, and is accountable to them.
- Graduated sanctions. A first breach is met mildly, repeated breaches more firmly.
- Quick settlement of disputes. Conflicts can be resolved locally, fast and at low cost.
- Recognition. Outside authorities do not deny the users the right to make their own rules.
- Nested layers. Larger systems are organised in several layers, with small local units at the base.
In 2009 Ostrom received the Nobel Memorial Prize in Economic Sciences, shared with Oliver E. Williamson, for her analysis of economic governance, especially the commons. She was the first woman to receive the prize in economics.
Common rights in Sardinia
Sardinia has its own long history of the commons. For centuries the people of a village held customary rights on the land of their territory: to graze their animals, to cut wood, to gather acorns and, on some land, to sow. These rights were called ademprivio, a word of Catalan origin, and in Italian they belong to the wider family of the usi civici, the civic uses. They were a form of collective use, usually free of charge.
On 6 October 1820 King Vittorio Emanuele I issued the Edict of Enclosures, the editto delle chiudende. It allowed owners to enclose their land with hedges, walls or ditches, provided it was not burdened with rights of grazing, passage, springs or watering, and it allowed the municipalities to do the same with their own land. The aim was to promote agriculture and a firmer form of private ownership. In practice the edict led to abuses: land that had been used in common was fenced in, and those who had grazed there lost access. Discontent turned into unrest in many places, and historians judge the success of the reform very differently.
After the unification of Italy, law no. 2252 of 23 April 1865 abolished the ademprivi and the rights of cussorgia on the island. In Nuoro the sale of communal land led to a revolt on 26 April 1868. Led by Pasqua Selis Zau, called Paskedda, a widow of about sixty, more than three hundred people marched to the town hall and burned the documents of the sale. Their cry, torramus a su connottu, means "let us return to what we know". The land was sold all the same.
The collective lands did not disappear. According to research by the Sardinian regional agency Argea, reported by L'Unione Sarda in 2021, land with civic uses still covers about 305,000 hectares, around 12.7 percent of the island. This article tells the history; it does not interpret the law that applies to such land today.
Knowledge and seed as commons
The idea of the commons has moved from the meadow to new resources. In Understanding Knowledge as a Commons (2007), Charlotte Hess and Elinor Ostrom asked the same questions of knowledge: who may use it, who maintains it, and which rules protect it. Knowledge has a special property. It is not used up when it is shared, so its danger is not overuse but enclosure through closed access and exclusive rights.
Seed is the oldest knowledge commons of farming. Every variety carries the choices of generations who saved it, sowed it and passed it on. The Open Source Seed Initiative, founded in the United States in 2012, puts this tradition into a pledge that travels with the seed: anyone may use the seed freely, but promises not to restrict others' use of it or its descendants by patents or other means, and to pass the pledge on with it. In Germany the initiative OpenSourceSeeds, an offshoot of the organisation Agrecol, introduced a comparable licence in 2017. The first variety under it was the cocktail tomato Sunviva, bred at the University of Göttingen. Seed swaps and seed libraries follow the same idea without any licence, as described under seed saving and exchange.
The commons and permaculture
Among the three ethics of permaculture, fair share asks for limits and for passing on surplus. A commons is one of the oldest forms in which people have practised exactly this: taking only what the resource can renew and contributing to its care. David Holmgren counts land tenure and community governance among the seven domains of his permaculture flower, and among its examples he names traditional use rights, cooperatives and ecovillages.
In the language of permaculture a commons is an invisible structure. It does not appear on the site plan, yet it decides whether a pasture, a spring or a seed collection lasts. Ostrom's principles read like design rules for such structures. Monitoring and graduated sanctions are feedback loops, the subject of the principle apply self-regulation and accept feedback. The say of those affected is what methods such as sociocracy try to secure inside a group. And the old pastures, from the Alps to Sardinia, are a reminder that managed grazing on shared land depends on shared rules.
Common mistakes
- Confusing commons with open access. A resource without community and rules is not a commons. Hardin's tragedy applies to it; Ostrom's evidence does not.
- Romanticising. Ostrom also studied commons that failed. Shared use is not good in itself; it lasts where its rules fit the place and the people.
- Rules without a say. Rules imposed from outside are kept less well than rules the users have made themselves.
- Nobody watching. Without monitoring, overuse is noticed only when the damage is done.
How Terra Humana understands the commons
For Terra Humana the commons is a reminder that care for land has long been a shared task, bound to rules that people made for themselves. The history of Sardinia shows how closely the use of land and the life of its communities belonged together, and what was lost when that bond was cut. The form of the commons closest to our own work is knowledge: what we learn about soil, water and plants we share openly, so that others can build on it.
Sa Medada
What this looks like at Sa Medada
Sa Medada lies in Jerzu, in Ogliastra on the east side of Sardinia, the island whose history of common rights this article tells. The commons closest to the work of Terra Humana is knowledge: this TerraWiki is free to read, and the foundation documents what it tries at Sa Medada, including what does not yet work. Whether and how Project Eden will save its own seed is still open.
More about Project EdenFrequently asked
What is a commons?
A commons has three parts: a resource, such as a pasture, a forest, a spring, a fishing ground, seed or knowledge; a community that uses it; and the rules by which that community takes from it, cares for it and settles its disputes. Economists call the resource itself a common-pool resource. What makes it a commons is the third part, the shared rules. A meadow that anyone may use without any agreement is not a commons in this sense but open access.
What is the tragedy of the commons?
It is the title of an essay by the biologist Garrett Hardin in the journal Science in 1968. Hardin imagined a pasture open to all: each herder gains the full benefit of one more animal, while the damage of overgrazing is shared by everyone, so each keeps adding animals until the pasture is ruined. As remedies he saw private property or control by the state. Thirty years later Hardin conceded in Science that he should have written of the unmanaged commons, because his pasture had users but no rules.
What did Elinor Ostrom find out about the commons?
In Governing the Commons (1990) the political scientist Elinor Ostrom showed that communities around the world have managed shared pastures, forests, fisheries and irrigation systems over long periods, without privatising them and without handing them to the state. From these cases she drew eight design principles, among them clear boundaries, rules that fit the place, a say for those affected, monitoring and graduated sanctions. In 2009 she received the Nobel Memorial Prize in Economic Sciences, the first woman to do so.
What were the ademprivio and the Edict of Enclosures in Sardinia?
Ademprivio was the Sardinian name for customary rights of the people of a village on the land of their territory, such as grazing animals, cutting wood and gathering acorns. On 6 October 1820 King Vittorio Emanuele I issued the Edict of Enclosures, the editto delle chiudende, which allowed owners to fence in land not burdened with such rights. It led to abuses and unrest. A law of 23 April 1865 abolished the ademprivi, and in 1868 the sale of communal land in Nuoro led to the revolt known as Su Connottu.
What are knowledge and seed commons?
They apply the idea of the commons to resources that are not used up by sharing. Charlotte Hess and Elinor Ostrom described knowledge as a commons in 2007. For seed, the Open Source Seed Initiative, founded in the United States in 2012, attaches a pledge to its varieties: anyone may use them freely but must not restrict others' use through patents or other means. In Germany the tomato Sunviva, bred at the University of Göttingen, was the first variety released under an open-source licence, in 2017.
What do the commons have to do with permaculture?
The permaculture ethic of fair share asks for limits and for passing on surplus, and a commons is one of the oldest forms in which people have practised it. David Holmgren counts land tenure and community governance among the seven domains of his permaculture flower and names traditional use rights among its examples. In permaculture terms a commons is an invisible structure, and Ostrom's design principles read like a checklist for any shared resource, from a spring to a seed collection.

Related terms






Mentioned in
See this in practice
Further reading from around the world
Freely available sources we recommend for going deeper.
Sources
- Hardin, G., The Tragedy of the Commons, Science 162, pp. 1243-1248 (13 December 1968)
- Hardin, G., Extensions of 'The Tragedy of the Commons', Science 280 (1 May 1998)
- Ostrom, E., Governing the Commons: The Evolution of Institutions for Collective Action, Cambridge University Press (1990)
- Hess, C. and Ostrom, E. (eds.), Understanding Knowledge as a Commons: From Theory to Practice, MIT Press (2007)
- Royal Swedish Academy of Sciences, The Prize in Economic Sciences 2009, press release (12 October 2009), nobelprize.org
- UNESCO, Irrigators' tribunals of the Spanish Mediterranean coast: the Council of Wise Men of the plain of Murcia and the Water Tribunal of the plain of Valencia, Representative List of the Intangible Cultural Heritage of Humanity (2009)
- Visit València, The Water Court (Tribunal de las Aguas), visitvalencia.com (accessed October 2026)
- David Holmgren, Permaculture flower domain: Land tenure and community governance, permacultureprinciples.com (accessed October 2026)
- Treccani, Vocabolario, ademprivio, treccani.it (accessed October 2026)
- Regio editto sopra le chiudende, Kingdom of Sardinia (6 October 1820)
- Legge 23 aprile 1865, n. 2252, on the abolition of the ademprivi and the rights of cussorgia in Sardinia
- Lucato, C., Storia di Paskedda (10 figli) eroina 'per caso' nella Sardegna dell'Ottocento, AGI (23 January 2022)
- Rais, M., Usi civici, l'Isola cerca la via per lo sviluppo, L'Unione Sarda (24 October 2021)
- Open Source Seed Initiative, Origins and Orientation, osseeds.org (accessed October 2026)
- University of Göttingen, Eine Tomate für alle: Sunviva ist Gemeingut, press release no. 268 (7 December 2018)
Last updated: 2026-10-19
