Your salary is made of salt. Not literally – your bank isn't quietly filling a vault with sodium chloride somewhere in Leeds – but the word itself is. "Salary" comes from the Latin *salarium*, which probably referred to a salt allowance paid to Roman soldiers, or money given specifically to buy it. Salt preserved food, flavoured it, and was genuinely difficult to come by. So people decided it was worth something. And that decision, made by enough people at the same time, is essentially all that money has ever been.
The Romans weren't the only ones to play this trick. On the other side of the world, the same sleight of hand was being performed with cowrie shells – small, glossy, and satisfying to hold. Apparently that was enough. West African traders, Indian merchants, and Chinese dynasties all used them as currency for centuries. Nobody was confused about what a cowrie shell was. It was a shell. It just also happened to be money, because enough people said so.
The Dutch, who were not easily fooled about most things, managed to convince themselves in the 1630s that tulip bulbs were an appropriate store of value. A single Semper Augustus bulb reportedly sold for roughly the price of a grand Amsterdam townhouse. Then confidence wobbled. The tulip market collapsed spectacularly, and everyone remembered that it was a bulb. The flowers were beautiful, obviously. But the value had never really been in them.
Then there's the example that economists still genuinely love: cigarettes in prisoner-of-war camps during the Second World War. In Stalag Luft III and similar places, cigarettes became the accepted currency almost immediately. Prices were quoted in them, and even non-smokers held them as savings. They were portable, divisible, and – crucially – everyone agreed they were worth something. Standard issue became money. For more on how trust turned ordinary objects into economic foundations, When the Sun Gave Economics Its Favourite Word.
The same logic applies to the paper money in your wallet right now. A twenty-pound note is cotton and linen, worth almost nothing as a physical object. What makes it £20? The same thing that made a cowrie shell valuable, or a tulip bulb briefly extraordinary: collective agreement. The Bank of England promises to honour it, you believe the promise, the shopkeeper believes you believe it, and suddenly the whole thing functions. It's the longest-running confidence trick in human history, and the extraordinary part is that it works best when nobody thinks of it as a trick at all.
What's worth sitting with is that every attempt to find a *real* currency – one with intrinsic, unshakeable value – turns out to have the same wobble underneath. Gold is just a metal. Bitcoin is just code that enough people decided to trust. Salt was just salt.
The useful thing about knowing this isn't cynicism. It's the reminder that financial systems are built on trust, which makes trust worth protecting more carefully than anything you could actually hold.
