The cryptocurrency revolution, which started with bitcoin in 2009, claims to be inventing new kinds of money. There are now nearly 2,000 cryptocurrencies, and millions of people worldwide are excited by them. What accounts for this enthusiasm, which so far remains undampened by warnings that the revolution is a sham?

One must bear in mind that attempts to reinvent money have a long history. As the sociologist Viviana Zelizer points out in her book The Social Meaning of Money: “Despite the commonsense idea that ‘a dollar is a dollar is a dollar,’ everywhere we look people are constantly creating different kinds of money.” Many of these innovations generate real excitement, at least for a while.