I have set up next to a pottery stall because I want a few of the multicoloured bowls that he has lined up on a wooden trestle. A neighbour joins us carrying shawls and scarves on his shoulders and I would like to choose one or two of them for my wife. We start talking. We realise that each of us wants something that the other owns. This is a good thing. However, after only a few moments of negotiation, we are completely engrossed on our butter-pottery, chicken-shawl, shawl-pottery, shawl-eggs, etc. exchanges that we don’t know where we are. It is at this point that I suggest we use an egg as a unit. Everything becomes clear: we agree on an estimated value for my butter, my chickens, their shawls and their bowls expressed in eggs. We negotiate a bit more but eventually the deals are struck.

My eggs have not been touched but they served as a common denominator as the retired London trader, who now rears snails, explained, they satisfied the first requirement of a currency: that of measuring value. They have become an accounting currency and I started looking at them differently.

An osteopath that I know comes by: he’s a good man and had quickly replaced my shoulder when it became dislocated the previous week. “I am not ungrateful” I said to him, “and every service merits its reward. Take something from my wares that you think is appropriate.” He thanks me but hesitates because he already has plenty of what I have available. “Give me some of your eggs anyway” he says, “Eggs can always be swapped for other things.” This means my eggs have now obtained a new quality, they have become a trading currency, they satisfy a second requirement of a currency: they are an instrument of exchange; They are really being honoured.

An hour later, as I left the Café du Commerce where I had ended the morning, I met the osteopath. “I’ve kept a dozen of your eggs” he told me, “I am going to use them to buy some pasta tomorrow; the store has sold out today.” My eggs are going to satisfy a third requirement of a currency, that of being a reserve of value, an investment instrument. They have become a true currency.

Would it not be helpful given this if I gave my eggs a higher value than I had up until now? Does this flattering choice not justify that I increase their price? They have acquired a monetary value that is in addition to their commercial value and I am delighted. However, two days later, my neighbour visits me and inadvertently provides the answers to the questions I have been asking myself: “I have heard that the osteopath, even though a careful man, has tripped on a stone and fallen, his basket overturned and his eggs have become an omelette – to the great pleasure of the children who were watching all of this.” I concluded from this that my arguments are correct for a good currency but unfortunately eggs are not a good currency and all their glory disappears before my eyes…