What credit theorists like Mitchell-Innes were arguing is that even if Henry gave Joshua a gold coin instead of a piece of paper, the situation would be essentially the same. A gold coin is a promise to pay something else of equivalent value to a gold coin. After all, a gold coin is not actually useful in itself. One only accepts it because one assumes other people will. In this sense, the value of a unit of currency is not the measure of the value of an object, but the measure of one's trust in other human beings. This