 Historians of money and monetary theorists divide kinds of money along more nuanced dimensions. A few historical cases may qualify as fiat money, such as in Ming dynasty China, revolutionary France, and the American Confederacy, but these were fragile and subject to collapse (Yang 1952, Ferguson 2008, Spang 2015). But many contemporary approaches emphasize the role of private interactions in the creation of money, and importantly, reserve banking as well as credit and debt markets. Other theories emphasize the role of the state, and in particular the central roles of interest-rate-setting institutions, government debt, and the collection of taxes (see Friedman &amp; Schwartz 1963, Kaldor 1985, Moore 1988, Deleplace &amp; Nell 1996). In these approaches, questions about the “substance” of money become rather peripheral.