The Pasture Hardin Imagined and the Commons Ostrom Found

In December 1968 the biologist Garrett Hardin published an essay in the journal Science that gave economics and ecology one of their most quoted phrases. The tragedy of the commons described a pasture open to all, in which each herder gains the full benefit of adding one more animal while the cost of overgrazing is shared among everyone. Reason, Hardin argued, leads every herder to the same ruinous conclusion. Freedom in a commons, he wrote, brings ruin to all.

The parable travelled far beyond biology. It was used to justify the privatisation of grazing land, the state control of forests and fisheries, and, in Hardin's own hands, coercive limits on population. Its logic was seductive because it required no villains. Ordinary rational behaviour, multiplied, was enough to empty a pasture. For policy makers in newly independent states anxious about forests, water and land, it offered a tidy principle, namely that whatever belongs to everyone will be spoiled, so it should belong to someone.