Economists² tend to study "the market" in the abstract, but some markets are anything but abstract. The Aalsmeer auctions³ in the Netherlands burst with the colour of more than 20 million flowers a day, while Tokyo's early-morning Tsukiji fish market (lovingly described on page 16) is enthralling⁴ enough to compete for tourist attention with the nightclubs of Roppongi. (The stink⁵ of alcohol in the tourist pens of Tsukiji suggests that many visitors have combined both experiences to make a night of it.)

除了游客之外，这些著名的市场也值得经济学家关注。很多经济学理论都有假设前提，不考虑市场交易实际如何进行。这是一件令人惋惜的事；斯坦福大学(Stanford)已故经济学家约翰o麦克米兰(John McMillan)认为，市场只有在设计完备的情况下才能运转良好。市场的全部理念在于使人们能够从交易中获利；设计糟糕的市场通常会失败。

These celebrated⁶ markets deserve attention from economists as well as tourists. A lot of economics assumes away the details of how market transactions actually work. That is a shame; the late John McMillan, an economist¹ at Stanford, argued that markets will only work well if they are well designed. The whole idea of a market is to allow gains from trade to take place; a badly thought-out market will often fail.

即使对于像买鱼这样简单的交易，事情也并不像乍看上去那样简单。

There is more than meets the eye even to a simple transaction such as buying fish.

经济学家凯瑟琳o格雷迪(Kathryn Graddy)曾经花了一个月时间，追踪纽约富尔顿鱼市(Fulton Fish Market)中的一位鱼商。她大清早就要起床，而且要交保护费才能把车停到离市场较近的安全地点。她发现，鱼商似乎对不同种族的人要不同的价格--尤其明显的是，亚裔买家往往会拿到比白人更有利的价格。一个可能的解释是，亚裔买家在唐人街拥有对价格更加敏感的客户。

The economist Kathryn Graddy once spent a month shadowing a trader at the Fulton Fish Market in New York, rousing herself in the early hours and paying protection money to park her car in a safe spot near the market. She discovered that market traders appeared to charge different prices to different ethnic⁷ groups - in particular, Asian buyers tended to win keener prices than white buyers. The likely explanation was that the Asian buyers had more price- sensitive customers in Chinatown.

尽管如此，这仍是一个令人惊讶的结果。

Still, this was a surprising result.

在一个竞争性市场，鱼商应该无法向白人客户要更高的价，而富尔顿鱼市理应是一个竞争性市场：它是全球第二大鱼市。（筑地鱼市场的规模是富尔顿鱼市的5倍多，完全不是一个级别）。格雷迪发现，即使在富尔顿鱼市，完全竞争也难觅踪迹。

A competitive market should eliminate the traders' ability to charge white customers more, and the Fulton Fish Market should be competitive: it is the world's second largest. (Tsukiji, more than five times larger, is in a league of its own.) Graddy discovered that even at Fulton, perfect competition was elusive⁸.

然而，市场运转得越好，达成的交易就可能越多。我们或许想要压制交易，但一些交易如此诱人，以至于压制力有多大，抵抗力就有多大：无论学校商店是否有巧克力棒存货，学生都会弄到巧克力棒吃。在混乱的索马里首都摩加迪沙，私营商人想出了使电力市场在没有电表的情况下也能运转的方法：客户根据其家中或者商铺里的电灯泡数量付费。

Nevertheless, the better markets work, the more transactions they make possible. Some transactions are so tempting⁹ as to be irrepressible, much as we might want to repress them: school children will be supplied with chocolate bars whether or not the school shop stocks them. Other transactions are inspiring in their resilience. In the chaos¹⁰ of Mogadishu, Somalia, private merchants have worked out ways to get the market for electricity to work without metering; customers pay according to the number of bulbs in their home or workshop.

然而，许多交易需要的支持远多于此。现代交易基础设施包括法律体系、征信记录、签证和公司账户。举例来说，买股票看上去并不太复杂，但当你买股票时，你就等于将资金借给一家公司（例如说一家中国公司），换取与该公司分享未来盈利的权力。

Yet many transactions require a lot more support than that. Modern transaction infrastructure¹¹ includes the legal system, credit registries, Visa and corporate¹² accounts. Buying shares may not seem very sophisticated, for instance, but when you buy a share you are lending money in exchange for a claim on the future profitability of a firm in, say, China.

要想使这种日常金融交易成为可能，会计师、监管者、经纪商和律师阶层必不可少。

This everyday financial transaction requires layers of accountants, regulators, brokers¹³ and lawyers to make it possible.

经济的进步，很大程度上就是降低交易成本，使更为先进复杂的交易成为可能。尽管交易成本有所降低，但它给现代经济造成了前所未有的消耗。约翰o沃利斯(John Wallis)和诺贝尔经济学奖得主道格拉斯o诺斯(Douglass North)曾经试图通过考察会计、法律、零售、管理和警察等行业的规模，来衡量总交易成本。他们发现，在1870年至1970年间，具有交易成本的行业在美国经济中所占比重已经从逾四分之一上升到略高于50％，提高了一倍。交易成本并不低廉，但由于我们在1970年比1870年富裕得多，因此，所有这些支出似乎都值得。

Much economic progress consists of reducing transaction costs to allow more sophisticated transactions to take place. Although transaction costs have fallen, modern economies are ever more consumed by them. John Wallis and Nobel laureate economist Douglass North once tried to tot up transaction costs by looking at the size of sectors¹⁵ such as accountancy, law, retail¹⁶, management, policing and so on. They found that the transaction-cost sector¹⁴ doubled its share of the US economy, from just over a quarter in 1870 to just over half in 1970. Transactions don't come cheap, but since we were much richer in 1970 than in 1870, all this spending seems to have been worth it.

这一点值得记住。交易成本似乎通常意味着浪费、混乱或者官僚主义，但如果没有那些律师、会计师、秘书和销售人员，就没有现代经济。希望所有的交易成本都能像阿斯米尔花市或者筑地鱼市场那样，成为令人心动的一景。

That is worth remembering. Transaction costs often seem like waste, chaos or bureaucracy, but without all those lawyers, accountants, secretaries and sales staff, a modern economy would be impossible. If only all transaction costs could be as thrilling a spectacle as Aalsmeer or Tsukiji.