In some ways, the Problem of the Commons forms the core of all liberal philosophy. If the world were different, or the people who live in it different, it would not be a problem. This essay hopes to explain what the issue is, and how it relates to a good portion of what are commonly seen as liberal or progressive political positions in the west.
The Tragedy of the Commons is a well-known conundrum when it comes to social engineering. Many good and talented people have written or spoken about it from various perspectives; one of my favorite is from game journalists Extra Credits. Here I present a simplified example, and then endeavor to explain how it relates to other political positions.
Traditional explanations start with grazing rights or parks, but something that a lot of red-state readers may find more relatable would be hunting and fishing, and the question of licensing such activities. In the scenario where there is no government control over hunting, say, deer, anyone could hunt any deer at any time. Ostensibly, a reasonable collection of individuals would avoid over-hunting in order to make sure there are deer in the coming years. They would hunt bucks and doe in equal proportion, and would take only their own fair share of the animals available.
History suggests, however, that this is not what happens. Instead, usually, a few individuals figure that they can benefit more if they hunt a bit more than their fair share. Others see them doing this and realize that, because the deer are being over-hunted, they will quickly be hunted out in the local area. In order to not lose out, they also hunt more than their fair share...to "get while the getting is good." This accelerates the loss of deer population, and quickly results in an area devoid of good hunting.
This isn't so much of a problem in lightly populated areas rich with deer, but as human populations increase and natural habitats shrink, it quickly becomes more of an issue. This is the Tragedy of the Commons: that resources not owned or protected by anyone are quickly depleted by individuals acting in a short-sighted manner.
The thing is, a lot of things fall into the category of the "commons." The sea and air are obvious modern examples, and so regulations on pollution seem like common sense from the perspective of anyone who believes we should leave a livable world for our children. But there are less obvious examples, as well.
For example, Democracy, in general, exists primarily as a way to express the will of the people. It was originally conceived as a way for a well-informed, well-educated population to express their political will in a collective manner. This implies the necessity of the populous to be well-informed and well-educated. In order for democracy to function, the members of that democracy must be sufficiently schooled in politics and critical thinking so that they may participate as effective members of that democracy. This means that education becomes a problem of the commons. Individuals acting on their own do not reliably become sufficiently informed to become effective citizens, but all benefit if everyone does, in fact, become well-educated.
Another good example is that of general economic health. Anyone with any economic background will tell you that the economy is most healthy when the middle class is strong. A strong middle class creates greater prosperity for everyone, millionaires and poor people alike; the pie becomes bigger. But an unregulated free market tends to shrink the middle class, creating an elite, super-rich class, and a broad swath of very poor people. Improving the plight of the most poor creates more demand for all services, increasing the velocity of money and improving the economy for all.
In this way, liberal programs like minimum wage and public education improve everyone's lot by more than they cost. By distributing these resources, in the way of taxes and regulations, to those less fortunate, it improves not only their quality of life, but increases the welfare of society in general.