アンチコモンズの悲劇
●James Surowieck, “The Permission Problem”（New Yorker, August 11, 2008）
The point isn’t that private property is a bad thing, or that the state should be able to run roughshod over the rights of individual owners. Property rights (including patents) are essential to economic growth, providing incentives to innovate and invest. But property rights need to be limited to be effective. The more we divide common resources like science and culture into small, fenced-off lots, Heller shows, the more difficult we make it for people to do business and to build something new. Innovation, investment, and growth end up being stifled.
Opportunities forgone aren’t always easy to see. The effects of overuse are generally unmistakable—you can’t miss the empty nets of fishing boats working overfished oceans, or the scrub that covers an overgrazed field. But the effects of underuse created by too much ownership are often invisible. They’re mainly things that don’t happen: inventions that don’t get made, useful drugs that never get to market.
アンチ「コモンズの悲劇」ではなくて「アンチコモンズ」の悲劇。
以下「アンチコモンズ」の悲劇に関する参考文献（私が目を通したことある範囲内）。
●Michael A. Heller（1998）, “The Tragedy of the Anticommons: Property in the Transition from Marx to Markets”（Harvard Law Review, vol.111(3), pp.621-688；ワーキングペーパーはこちら（pdf））
●M. A. Heller and R. Eisenberg（1998）, “Can Patents Deter Innovation? The Anticommons in Biomedical Research”（Science, vol.280, no.5364 (1 May 1998) , pp.698-701）
●James Buchanan and Yong Yoon（2000）, “Symmetric Tragedies: Commons and Anticommons”（Journal of Law and Economics, vol.43(1), pp.1-13）
ついでに。ハーディンの「コモンズの悲劇」。
●Garrett Hardin（1968）, “The Tragedy of the Commons”（Science, vol.162, no.3859（13 December 1968）, pp.1243-1248）
（追記）
コモンズの悲劇は複数の主体が共有地の使用権（rights of usage）を有しているために発生し、アンチコモンズの悲劇は複数の主体が共有地の排他権（rights of exclusion）を有しているために発生する（共有地を使用するためには排他権の所有者全員から（例えば使用料の支払いを通じて）使用許可を得ることが必要）。
With an explicit assignment of ownership in the resource, however, under privatization, a person, or agent, is given both usage and exclusion rights. She may exclude others from usage and, at the same time, may directly use the facility or allow others usage upon permission. The conventional commons ploblem emerges as more than a single person or agent is assigned usage rights. It is interesting that little attention has been given to the setting where more than one person is assigned exclusion rights that may be simultaneously exercised analogously to the similar exercise of usage rights in the familiar model. （James Buchanan and Yong Yoon（2000）, pp.3-4）
The basic logic is equivalent in the two cases. The inefficiency arises because the separate decision makers, each of whom acts in exercise of assigned rights, impose external diseconomies on others who hold similar rights. In the commons or usage side of the model, persons (or firms) may, by adding a unit of input to the common resource, reduce the productivity of all other inputs and the rents of each person. In the anticommons or exclusion side of the model, persons (or firm) may, by reducing inputs to the common facility (via price), reduce the rents available to others who also exercise potential exclusion rights. （James Buchanan and Yong Yoon（2000）, pp.4）
