There is a category of intellectual resource that behaves like a commons: it is not depleted by use, it grows richer as more people draw on it, and its enclosure impoverishes everyone who relied on open access. Language is the clearest example — it becomes more useful, not less, as more people share it. Mathematical notation, scientific method, certain legal concepts, the accumulated store of literary reference that allows one person to say something compressed and meaningful to another: all of these are commons of the mind.

What happens when a commons is enclosed is well documented in the physical world. The enclosure of English common land in the eighteenth and nineteenth centuries drove rural populations into cities, concentrated wealth, and destroyed ways of life that had sustained communities for centuries. The enclosure of intellectual commons is subtler but structurally similar. When concepts that were once freely available become proprietary, when the vocabulary for certain kinds of thinking is captured by interests that control its use, when educational systems become gatekeepers rather than pathways, the people who lose access to those commons are not merely inconvenienced. They are disarmed.

The defence of the intellectual commons is not a romantic cause. It is a practical one. A society whose members cannot think clearly about their situation, because the tools for that thinking are not freely available, is a society that will make poor collective decisions. The quality of public reasoning depends on the quality of the cognitive resources that are commonly held.

This is why the history of education is, at its best, a history of expanding access to the tools of thought. And why the corruption of education — the replacement of genuine intellectual formation with credentialing, compliance, and the delivery of approved conclusions — is not merely a waste of money but a slow degradation of the commons on which everything else depends.