My Thanksgiving column about how the pilgrims nearly starved practicing communal farming but thrived once they switched to private cultivation made some people angry. One commented, "Sharing of the fruits of our labor is a bad thing?"

I never said that.

I practice charity regularly. I believe in sharing. But when government takes our money by force and gives it to others, that's not sharing.

And sharing can't be a basis for production -- you can't share what hasn't been produced. My point is that production and prosperity require property rights. Property rights associate effort with benefits. Where benefits are unrelated to effort, people do the least amount necessary to get by while taking the most they can get. Economists have a pithy way of summing up this truth: No one washes a rental car.

It's called the "tragedy of the commons." The idea is as old as ancient Greece, but ecologist Garrett Hardin popularized the phrase in a 1968 Science magazine article. Hardin described a common pasture on which anyone may graze his livestock. Each person will benefit from a larger herd but will suffer only a tiny fraction of the negative effects of overgrazing. Public Choice economists call this "concentrated benefits and dispersed costs."

That's a recipe for depleting the resource. If a herdsman were to leave a portion of the commons ungrazed, someone else would gain the benefit, so why leave it ungrazed? Soon, all the grass is gone, and the livestock die. That's the tragedy of the commons.

There are two possible solutions. One is to put someone in charge. But that someone would have arbitrary power over the rest -- he may give his friends better terms -- and one individual can't possibly know how to plan the village economy.

The second solution, as the pilgrims learned the hard way, is private property. Property rights unite costs and benefits. If a herdsman owns part of the pasture, he reaps not only 100 percent of the benefits of enlarging his herd but also 100 percent of the costs. Under those conditions, he behaves differently. If he undergrazes, uses fewer pesticides, etc., to make sure that the pasture flourishes next year, he can anticipate the future benefits. So, he has a strong incentive to be a good steward of the land.

This principle is pertinent today. People lament endangered species and call for government action. But that is the inferior "solution" already discussed. What we need is private property.

Cows, chickens, turkeys and pigs are never at risk of becoming endangered. What's special about them? Only that individuals own these animals and sell them. That gives livestock owners an incentive to keep them healthy and plentiful year after year. Continued...