The most common mistake we make as teachers is attempting to tell our students too much.

Unless we can act collectively, there would be no way to defend ourselves, no way to define or enforce property rights. We couldn't curb congestion or pollution or build and maintain public infrastructure.

We've long known that firms can pay higher wages if they spend less on workplace safety enhancement. Libertarians ask, "If a worker is willing to accept higher wages in return for his agreement to exercise greater caution while performing his job, why should the government prevent him from making that choice?" It's a rhetorically powerful question, yet it overlooks the fact that the agreement in question will have adverse effects on others.

Many decry rising inequality because it makes those who've fallen behind feel impoverished. But it's done much more than cause hurt feelings. It has also raised the real cost to middle-income families of achieving many basic goals. The process begins with the completely unremarkable fact that top earners have been spending at a substantially higher rate than before. They've been building bigger mansions, staging more elaborate weddings and coming-of-age parties for their kids, buying more and better of everything.

Economics, as it is often taught today, portrays us as homo economicus-someone who doesn't vote in presidential elections, doesn't return lost wallets, and doesn't leave tips when dining out of town. Julie Nelson reminds us that most people aren't really like that. She helps point the way to a richer, more descriptive way of thinking about economic life.

John Stuart Mill believed that the only acceptable reason for government to limit a person's liberty was to prevent him from causing unacceptable harm to others. Mill was not a libertarian, but many libertarians are quick to cite this principle when arguing against a regulation that they oppose. And I believe most thoughtful libertarians are prepared to embrace something fairly close to Mill's harm principle. But accepting that principle implies accepting many of the institutions of the modern welfare state that libertarians have vigorously opposed in the past, such as safety regulation.

All parents want to send their children to the best possible schools. But because a good school is a relative concept, a family cannot achieve its goal unless it outbids similar families for a house in a neighborhood served by such a school. Failure to do so often means having to send your kids to a school with metal detectors at the front entrance and students who score in the 20th percentile in reading and math. Most families will do everything possible to avoid having to send their kids to a school like that. But because of the logic of musical chairs, they're inevitably frustrated.