Money is commonly described/explained as a ‘medium of exchange’ and a ‘store of value’. But this is a poor explanation: first, it expresses the matter as a peculiar metaphor (it mystifies as much as illuminates); second, it addresses incidental detail instead of directly grasping the key.
The most important aspect of money is how it works systematically: how it relates to collective, cooperative, activity. Because cooperative systems are important: they are more effective than disorganised individuals – often to a tremendous degree.
What is cooperation? The essence of cooperation is information shared between individuals. (Cooperation is separate things behaving according to a shared structure – and how is structure shared across separate physical things, except by information?)
This is what money does, and part of why ‘capitalism’ (or whatever it is, or want to call it) has been so successful. Money is a crude mechanism of sharing something, of making a focus, and to very large scales. When money is accumulated it is effectively an accumulation of the effort of all the individuals it has come from – and the person with it is effectively controlling those individuals by directing the use of it.
The ‘Debt, The First 5000 Years’ guy, David Braeber, describes that originally people used what might be called a favour system. If someone you knew needed a cow, you would give them one of yours, and when you needed help to make an axe, someone would give some of their time and effort to you.
But that provides no easy way to accumulate – that is, create a (large scale) shared focus. Money is a simple discrete material representation that does. The material features preferentially induce particular cooperative behaviours.
People do things. There is no ‘store of value’, there is no ‘medium of exchange’ – that view, in two intriguing phrases, confuses the underlying purpose with the incidental mechanism (and prejudices any enquiry in favour of that particular implementation). It is really a question of what people do, when and where, etc., and how to organise that.
When you see money in this more abstract (and also concrete) way – as a mechanism to support cooperation – the most remarkable thing is just how primitive it is. (This is a curative to the odd inability to imagine any alternative to modern ‘capitalism’.) Cooperation is about the flow of information between individuals. Maybe it does not need much complexity, but it seems obvious that it could now be done differently and better than money.
Money is really an information channel, and it is now an obsolete technology.