fisherman. I just caught a boat-load of fish, and I want to exchange all these fish for a new suit. Without an “exchange medium”, his is very difficult to do. But with an exchange medium, it's easy.

我是打鱼的，刚捕了一船鱼。我想用这船鱼换一套新衣服。在没有“交易媒介”的情况下，这笔交易很难做成；有了交易媒介，这笔交易就很容易做。

　 What will I accept as a medium to help me exchange my fish for a new suit? I'll accept anything for my fish--I don't care what it is--so long as I am sure the suit-seller will accept it in exchange for a suit. If there is any doubt about whether or not the suit-seller will accept it for a suit, then I will not accept it for my fish. If I think he might not accept it, then I will not accept it.

我原意接受的物品作为交换媒介，它能帮我用这船鱼换回一套衣服。我愿意用这船鱼换任何物品—我不介意它是何物—只要我能肯定卖衣服的人原意接受它，我能用它换到一套衣服；如果对这一点有怀疑，我就不会用这船鱼与之相交换；如果我认为卖衣服的人不会接受这件物品，那我也不会接受它。

　 Now, let's be more realistic. A fisherman really doesn't want to exchange his boat-load of fish just for a suit. He wants groceries, electricity, water, housing and a few glasses of beer. So whatever he accepts in exchange for his fish can not be something acceptable only to the suit-seller. It must be something that is acceptable to all those other people, too. Why do all those other people accept it? Only because they are confident that everyone they do business with will accept it. See how it all ties together? When everyone is confident that everyone else will accept something as money, then that something becomes generally acceptable. Then, and only then, it is money.

现在，让我们回到现实社会中来。有位渔夫并不是想用这船鱼只换一套衣服，他想换回食品杂货、交水、电费、交房租，还要换几杯啤酒。因此，无论他用这船鱼换到什么物品，这件物品都不能仅仅是这位卖衣服的人愿意接受，还必须是所有其他人都愿意接受的物品。他们为何愿意接受它呢？就是因为他们相信这些做生意的人都愿意接受它。注意它是如何成为一般等价物的？当大家认识到人人都愿意接受某种物品为货币时，这时它就会被普遍接受。这时，只有这时，它就成为货币。