Herman Daly is an American ecological economist and professor at the School of Public Policy of University of Maryland, College Park in the United States.
He was Senior Economist in the Environment Department of the World Bank, where he helped to develop policy guidelines related to sustainable development. While there, he was engaged in environmental operations work in Latin America. He is closely associated with theories of a Steady state economy.
Herman Daly, letting yall know what’s up (as always):
There are two sets of important distinctions about goods, and they make four cross-classifications (see figure below). Goods can be either rival or non-rival, and they can be either excludable or non-excludable. My shirt, for example, is a rival good because if I’m wearing it, you can’t wear it at the same time. The warmth of the sun is non-rival because I can enjoy the warmth of the sun, and everyone else can enjoy it at the same time. Rivalness is a physical property that precludes the simultaneous use of goods by more than one person. Goods are also excludable or non-excludable. That’s not a physical concept, that’s a legal concept, a question of property. For example, you could wear my shirt tomorrow if I let you, but that’s up to me because it’s my property. My shirt is both rival and excludable, and that’s the case with most market goods. Meanwhile, the warmth of the sun is both non-rival and also non-excludable. We cannot buy and sell solar warmth; we cannot bottle it and charge for it. Goods that are rival and excludable are market goods. Goods that are non-rival and non-excludable are public goods. That leaves two other categories. Fish in the ocean are an example of goods that are rival and non-excludable. They are rival, because if I catch the fish, you can’t catch it. But they are also non-excludable, because I can’t stop you from fishing in the open seas. The management of goods that are rival and non-excludable gives rise to the famous tragedy of the commons – or the tragedy of open-access resources, as it’s more accurately called. Now, the other problematic category consists of goods that are non-rival and excludable. If I use the Pythagorean Theorem, I don’t prevent you from using it at the same time. Knowledge is non-rival, but it often is made excludable through intellectual property and patent rights. So those are two difficult categories that create problems. One is the tragedy of the commons, and the other we could call the tragedy of artificial scarcity.