Education used to be a private good with positive externalities. Thanks to technology and government largesse it is no longer the case. It is being transformed into a nonpure public good.
Technology-borne education is nonrivalrous and, like its traditional counterpart, has positive externalities. It can be replicated and disseminated virtually cost-free to the next consumer through the Internet, television, radio, and on magnetic media. MIT has recently placed 500 of its courses online and made them freely accessible. Distance learning is spreading like wildfire. Webcasts can host - in principle - unlimited amounts of students.
Yet, all forms of education are exclusionary, at least in principle. It is impossible to exclude a citizen from the benefits of his country's national defense, or those of his county's dam. It is perfectly feasible to exclude would be students from access to education - both online and offline.
This caveat, however, equally applies to other goods universally recognized as public. It is possible to exclude certain members of the population from being vaccinated, for instance - or from attending a public concert in the park.
Other public goods require an initial investment (the price-exclusion principle demanded by Musgrave in 1959, does apply at times). One can hardly benefit from the weather forecasts without owning a radio or a television set - which would immediately tend to exclude the homeless and the rural poor in many countries. It is even conceivable to extend the benefits of national defense selectively and to exclude parts of the population, as the Second World War has taught some minorities all too well.
Nor is strict nonrivalry possible - at least not simultaneously, as Musgrave observed (1959, 1969). Our world is finite - and so is everything in it. The economic fundament of scarcity applies universally - and public goods are not exempt. There are only so many people who can attend a concert in the park, only so many ships can be guided by a lighthouse, only so many people defended by the army and police. This is called "crowding" and amounts to the exclusion of potential beneficiaries (the theories of "jurisdictions" and "clubs" deal with this problem).
Nonrivalry and nonexcludability are ideals - not realities. They apply strictly only to the sunlight. As environmentalists keep warning us, even the air is a scarce commodity. Technology gradually helps render many goods and services - books and education, to name two - asymptotically nonrivalrous and nonexcludable.
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