Résumé en anglais

The objective of this article is to identify the monetary plurality in economic theory. We will try to throw light on the way in which theories are attracted towards both unicity and plurality, and more specifically by unification and diversification of money. It should also be noted, in this respect, that the economics of money has undergone considerable development since the 1970s. A survey of the diverse theories, whether mainstream or not, static or dynamic, holistic or individualistic, will reveal the surprising amount of attention devoted to the problem of monetary unicity and/or plurality. We base our presentation on two lines of thought: -The first of these lines concerns a situation of general equilibrium, as opposed to theories giving place to the forms of disequilibrium and regime-crises. The general equilibrium theories usually see money as a financial asset and assume that it is neutral at least over the long term; theories of the second type, on the contrary, see money as a necessary condition for the development of trade, acknowledging that it influences the system of relative prices and consequently the dynamics of production. Thus money is presumed to be totally neutral (“super-neutral”) in the New Classical Economics in the manner of Lucas (1972, 1995) and in the New Monetary Economics initiated by Black (1970) and Fama (1980). On the contrary, it is not neutral according to neo-Mengerian approaches and to those that are neo-Marxist, Chartalist and post-Keynesian. -The second line of thinking revolves round the relationship between economic theories and the question of the unicity or plurality of money as a norm to be established. This relationship is often linked to the role assigned by the various approaches to finance. For example, the macroeconomics of the New Classical Economics school, in dealing with monetary “friction” within general equilibrium theory, maintains an approach that is largely “unitary”, seeking to integrate it into its framework. In this respect it opposes the financial views of the New Monetary Economics, that are based on a pluralist notion of money, aiming moreover to ensure that it could be dispensed it with the world of reality. Similarly, neo-Mengerian economists, who are pluralist and see financing as the heart of the proper organisation of money, are opposed to the unitarian approaches of Marxist, Chartalist and post-Keynesian economists. Our survey of contemporary theories will give rise to a typology of the forms of monetary unicity and plurality, framing a new reading of monetary theories.