Dear Economist
Dear Economist
How would an economist respond to the phrase "money is the root of all evil"?
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Mike Choe, via e-mail
Dear Mike,
Economists always seem to talk in dollars and cents, yet few economic models contain any reference to the stuff.
The reason why economists will use strange phrases such as "the value of a kiss is $49" is not that they think money is particularly important, but simply that it is a convenient way to measure things. If a toffee apple is worth $7 then a kiss is as good as seven toffee apples; however if the toffee apples cost $6 and the kiss costs $50 then the toffee apples are a better buy.
All that said, why do we have money at all, rather than using - for instance - toffee apples as a medium of exchange? One reason is that the price of toffee apples may fluctuate wildly, which means that although I could in principle write a contract denominated in toffee apples, it would be hard to have much confidence in what that contract really meant. Contracts in the ancient world were sometimes denominated in salt, because it had a stable price. These days, dollars are even better.
A complementary explanation is that money is a simple way for people to gain credibility. I can settle my debts by writing a note that says "I owe you one kiss," but I may not make good that promise, nor will you be able to use my IOU to pay for anything else. If, instead, I give you $49, this is a promise made by the US Treasury, a more dependable debtor.
In short, we need money because people simply don't trust each other. In the words of economists Nobuhiro Kiyotaki and John Moore, "evil is the root of all money".
邪恶是万种货币之源
亲
爱的经济学家：
有句老话叫“金钱乃万恶之源“，请问经济学家对此如何看待？
迈克?曹(Mike Choe)，通过电子邮件提问。
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亲爱的迈克，
经济学家们似乎总在谈论美元和美分，但几乎没有哪个经济模型包含任何对这些东西的推荐介绍。
经济学家们之所以使用诸如“一次接吻价值49美元”等奇怪的措辞，并非因为他们认为金钱特别重要，而是因为那是一种很方便的衡量事物的途径。如果一个苹果棒糖价值7美元，那么一次接吻实际上相当于7个苹果棒糖；然而，如果苹果棒糖售价6美元，而一次接吻花费50美元，那么苹果棒糖就更值得购买。
那么，我们为什么要用货币，而不是使用苹果棒糖之类的东西作为交换中介呢？原因之一是，苹果棒糖的价格可能会有很大的浮动，这意味着，尽管我可以签署一份以苹果棒糖为计价单位的合同，但很难确信这份合同真正意味着什么。在古代，合同有时以盐为计价单位，因为当时盐的价格很稳定。现在，美元的价格更为稳定。
一个补充的解释是，货币是人们获得信用的一个简单途径。我可以通过写一张“我欠你一个吻”的纸条，来处理我的债务，但我或许不能实现这个承诺，你也无法用这个借条购买其它任何东西。可是，如果我给你49美元，这便是一个由美国财政部做出的承诺，而美国财政部则是一个可靠得多的债务人。
简而言之，我们需要货币只是因为人们不信任对方。在经济学家清泷信宏(Nobuhiro Kiyotaki)和约翰?摩尔(John Moore)看来，“邪恶是万种货币之源”。
