 The credit theory of money: According to the main rival theory, coins and notes are merely tokens of something more abstract: money is a social construction rather than a physical commodity. The abstract entity in question is a credit relationship; that is, a promise from someone to grant (or repay) a favor (product or service) to the holder of the token (Macleod 1889, Innes 1914, Ingham 2004). In order to function as money, two further features are crucial: that (i) the promise is sufficiently credible, that is, the issuer is “creditworthy”; and (ii) the credit is transferable, that is, also others will accept it as payment for trade.