This note is a comment on José Antonio Bravo's post:

In my opinion, José Antonio Bravo's post confuses several different things: exchange, writing, accounting, unit of account, and money.

If the “Sumerians invented writing to express interchanges of goods”, then interchanges of goods already existed before that writing. Writing does not create exchange: it records it, formalizes it, or accounts for it.

If “they needed a unit of account to express interchanges”, this again acknowledges that there were already interchanges, debts, deliveries, or economic relations to express, compare, or account for. A unit of account may be a tool of calculation, but it is not the absolute condition of possibility for every exchange.

To say that “Without unit of account, it's really impossible to transact goods and services” goes too far. A direct exchange can take place without a common unit of account: I give wheat and receive hides, goats, salt, or tools. It may be clumsy, limited, hard to scale, and unsuitable for a complex economy, but it is not impossible.

Even if one accepted, for the sake of argument, that “Barter is a myth, and no civilization has done bartering”, that does not prove that direct exchange is a myth or that money has always existed. It would only show that history was more complex than a simple sequence of “pure barter → money”. There could have been credit, accounting, obligations, redistribution, reciprocal gifts, and direct exchanges without there yet being a commonly and generally accepted medium of exchange.

The decisive point is that money does not emerge as an abstract unit of account, but from goods that were already valued and demanded. When certain goods —cattle, salt, metals, shells, cacao, etc.— begin to be accepted not only for their direct use, but because others will probably accept them later, the transition from direct exchange to indirect exchange takes place.

And when that good becomes commonly and generally accepted as a medium of exchange, then we can properly speak of money.

Only then can it naturally function as a general unit of account. Not because the unit of account creates money, but because a widely accepted medium of exchange makes it easier to express prices, compare goods, and perform economic calculation.

Therefore, to say that “everybody needs a unit of account, and this is money” reverses the process. We do not use something as money because it is first a unit of account; it becomes a general unit of account because it has first been accepted as a medium of exchange.

A developed economy needs money, yes. But money is not born as abstract “code” or as a mere accounting unit. It is born from the practical problem of exchange, from the limitations of direct exchange, and from the progressive adoption of more saleable goods as media of exchange. First there are goods, valuations, action, and exchanges; then calculation; and only with the generalization of the medium of exchange does money fully emerge.