The question of the origin of money divides economists deeply. For mainstream economists and proponents of modern monetary theory, money is essentially an institutional creation, controlled and issued by central authorities. Austrian economists propose a radically different perspective, believing that money emerges from a natural, spontaneous market process.

Carl Menger formulated this revolutionary theory in his article "On the Origins of Money", published in 1892, in opposition to the German historical trend of Gustav von Schmoller, for whom money was a purely institutional product. To demonstrate the natural emergence of a unique exchange intermediary, Menger explains that in a barter economy, exchanges remain very limited. Economic agents must find partners with exactly the goods they need: the double coincidence of needs. This condition becomes impossible to satisfy in an economy that goes beyond the simple circle of restricted exchange. As a result, certain goods have gradually emerged as preferred intermediaries, becoming commodity currencies.

Menger relies on two key ideas: imitation and self-interest. Drawing on the Aristotelian tradition, he argues that the community always imitates the behavior of the most perceptive individuals. Only those behaviors that work are imitated. Menger writes that there is no better way for anyone to learn about their own economic interests than to see the economic success of those who use the right means.

Initially, only a limited number of economic agents recognize the advantage of such a procedure. Spontaneous imitation thus enables the rapid selection of the commodity with the greatest exchange potential. The notion of the entrepreneur - those perceptive individuals identified by Menger - is a fundamental concept of Austrian theory.

Menger observes that once the most tradable commodities have become money, this event substantially increases their own original tradability. The adoption of the most tradable commodity is self-reinforcing: the more it is accumulated, the more tradable it becomes. This is the network externality effect, where the benefit an individual derives from using a good is accentuated by the number of individuals who also use it. Accumulation leads to exchangeability, which increases demand, creating a virtuous circle.

By following this logic, Menger implies that knowledge and the dissemination of information are not uniform across the population. This disparity explains why imitation acts as a shortcut for individuals who have neither the time nor the knowledge to reach the same level of understanding as the most capable economic agents.

For Menger, self-interest plays an equally important role. Every economic agent who brings to market items with a lower capacity for exchange has an even greater interest in converting what he or she owns into items that have become currency. Individuals who do not use the new emerging currency gradually exclude themselves from the market. The adoption process takes place gradually, as individuals understand the benefits of adopting the same currency as the most efficient economic agents.

The first agents to adopt the new currency have an advantage, creating a race against time. The penalty incurred by any agent who doesn't adopt quickly includes the loss of time trying to dispose of its less-exchangeable merchandise, and the gradual loss of its ability to participate in exchanges. As Ludwig Lachmann explains, successful projects gradually crystallize into institutions, and the imitation of successful ones is the most important form by which the ways of the elite become the property of the masses. Recent archaeological discoveries, notably Lorenz Rahmstorf's work on the use of raw silver in Mesopotamia before the intervention of Sumerian temples, tend to confirm this theory of the spontaneous emergence of money.