Sharing the wealth of the commons: institutionalizing the commons could promote both economic equality and environmental protection.

We're all familiar with private wealth, even if we don't have much. Economists and the media celebrate it every day. But there's another trove of wealth we barely notice: our common wealth.

Each of us is the beneficiary of a vast inheritance. This common wealth includes our air and water, habitats and ecosystems, languages and cultures, science and technologies, political and monetary systems, and quite a bit more. To say we share this inheritance doesn't mean we can call a broker and sell our shares tomorrow. It does mean we're responsible for the commons and entitled to any income it generates. Both the responsibility and the entitlement are ours by birth. They're part of the obligation each generation owes to the next, and each living human owes to other beings.

At present, however, our economic system scarcely recognizes the commons. This omission causes two major tragedies: ceaseless destruction of nature and widening inequality among humans. Nature gets destroyed because no one's unequivocally responsible for protecting it. Inequality widens because private wealth concentrates while common wealth shrinks.

The great challenges for the 21st century are, first of all, to make the commons visible; second, to give it proper reverence; and third, to translate that reverence into property rights and legal institutions that are on a par with those supporting private property. If we do this, we can avert the twin tragedies currently built into our market-driven system.

DEFINING THE COMMONS

What exactly is the commons? Here is a workable definition: The commons includes all the assets we inherit together and are morally obligated to pass on, undiminished, to future generations.

This definition is a practical one. It designates a set of assets that have three specific characteristics: they're (1) inherited, (2) shared, and (3) worthy of long-term preservation. Usually it's obvious whether an asset has these characteristics or not.

At the same time, the definition is broad. It encompasses assets that are natural as well as social, intangible as well as tangible, small as well as large. It also introduces a moral factor that is absent from other economic definitions: it requires us to consider whether an asset is worthy of long-term preservation. At present, capitalism has no interest in this question. If an asset is likely to yield a competitive return to capital, it's kept alive; if not, it's destroyed or allowed to run down. Assets in the commons, by contrast, are meant to be preserved regardless of their return.

This definition sorts all economic assets into two baskets, the market and the commons. In the market basket are those assets we want to own privately and manage for profit. In the commons basket are the assets we want to hold in common and manage for long-term preservation. These baskets then are, or ought to be, the yin and yang of economic activity; each should enhance and contain the other. The role of the state should be to maintain a healthy balance between them.

THE VALUE OF THE COMMONS

For most of human existence, the commons supplied everyone's food, water, fuel, and medicines. People hunted, fished, gathered fruits and herbs, collected firewood and building materials, and grazed their animals in common lands and waters. In other words, the commons was the …