Is Fungibility a Requirement of Currency?

I’m no expert when it comes to money but an article shared by the inimitable Tony Fish earlier today piqued my interest. In the article by Ross Dawson he discusses
“Why reputation, influence, and attention are becoming central to economies but are not currencies” and in which (in my view correctly) talks about how,

Attention can certainly be used to pay for services, and the value can be readily quantified by comparing the cost of free ad-supported services with their ad-free alternatives. However the value of attention is unique to the individual, and also the context in which it is applied.

But still something about this article just doesn’t sit well with me. I suspect it’s the thought that the nature of currency doesn’t or hasn’t changed and that for something “new” to be considered a currency it must adhere to the old rules, the old definitions.

The notion that a currency must be fungible just doesn’t feel correct.  Indeed a quick hunt around the interwebs shows this question of a need for mutual substitution has been discussed at length many many times but that views are certainly still divided. This article by Venessa Miemis is as good a set of arguments as I’ve read so far.

What is apparent is that Dawson’s characteristics of currency don’t follow the accepted definitions of currency which seem to allow for interpretation as to what constitutes a medium of exchange.  Looking solely at that aspect a great many things have been used over the millennia as tokens of exchange and to the best of my knowledge not all goats are made equal – goats are not fungible.

I do agree with Dawson that to talk about things like reputation as a currency may not be useful, at least when discussing this in traditional terms, however it is clear to me that whilst in it’s infancy reputation, attention (and to a lesser degree influence) are indeed future financial instruments.