are hard to get, but hundreds of millions of Americans have a kidney to spare. The numbers

are heavily in our favor. The tragedy goes on year after year. Almost nobody wants to

do surgery to help a total stranger for free. And selling your kidney is illegal.

Voters, and the politicians they elect, have banned the trading of cash for kidneys. Why?

Because they underrate the social benefits of markets. They suffer from what I call anti-market

bias. People who have never studied economics often equate greedy intentions with bad results.

Economists share a standard objection to this bias. Thanks to competition, the surest way

to get rich is to make your customers happy. As the eighteenth-century economist Adam Smith

put it, It is not from the benevolence of the butcher, the brewer, or the baker that we expect our dinner, but from their regard for their own self-interest.

Think about reviews on websites like Yelp. If you give your customers good value, they'll

come back and tell others to do the same. If you rip your customers off, they go elsewhere

next time and tell others to do the same. When customers are free to choose, firms can't

put profits before people. If they do, they lose their people and their profits.

Economists appreciation for markets leads us to unconventional solutions to all sorts

of problems. Take the kidney shortage. Most people would shrug that there are no more

kidneys available. But that's false. If just one person in a thousand donated a kidney,

everyone on dialysis could get one.

There's just one problem. Asking someone to give you a kidney is a huge favor, the kind

of favor that only people who know and love you will agree to do. Love already saves a

lot of lives, but it's clearly not enough. So why not legalize a market for human kidneys,

where people who desperately need kidneys could buy one from a willing donor?

Regardless of their politics, almost no one who isn't an economist sees merit to this

idea, and almost everyone who is an economist does. Some worry that low-income people would

be first in line to sell. But what's wrong with making poor people rich, and sick people well?

This doesn't mean that economists always favor unregulated markets. Unlike a typical voter,

though, economists rarely complain because business is making money by solving a problem.

Economists complain when business isn't making money by solving a problem.

When a market visibly isn't working, economists try to figure out ways to jump start markets.

In many cases, slightly different government policies would do the trick.

Take air pollution. Many economists turn to government because they can't figure out how

a person could make money by cleaning the air. But that doesn't mean you can't have market.

Liberal economist Alan Blinder promotes tradable pollution permits to cut the cost of reducing

pollution. Instead of telling firms how to cut emissions, government could cap their

total emissions, then let firms with spare pollution permits sell them to other firms

that are over their quota. Blinder says this would reduce the cost of cleanup by at least

50 percent. When firms can sell their spare permits, they have a strong incentive to find cheaper ways to clean the air.

If markets can slash the cost of cleanup, why do voters resist the idea? Blinder blames

anti-market bias. The public seems to recoil in horror at the idea of selling the right

to pollute, as if even a small emission of a pollutant were immoral. There's always going

to be some pollution. As Blinder says, to think otherwise, is not to think.

When you can't imagine a way for business to make money solving a problem, it's tempting

to conclude that no one will ever think of a way for business to make money solving a

problem. Even economists, who pride themselves in their appreciation of markets, make this mistake.

If you went back in time to 1985 and described the Internet, most economists would have rolled

their eyes millions of free websites providing everything from directions to histories of

Germany. It'll never happen. Most economists would have been wrong, not because they had

too much faith in markets, but because they had too little faith in human imagination.