Money is the most fundamental technology in economics. It allows billions of strangers to trade, save, and invest without barter. But not all money is the same. The history of how humanity moved from commodity money to fiat money is the history of modern finance itself.
What money actually is
Economists define money by three functions: it must be a medium of exchange (accepted in transactions), a store of value (roughly the same worth tomorrow as today), and a unit of account (a common measure for pricing things). Any object can serve as money if enough people agree to use it. The key ingredient is trust — and the history of money is a history of what people have been willing to trust.
Commodity money: intrinsic value
Commodity money is currency made of — or directly backed by — a physical commodity with intrinsic value. Gold and silver coins were the classic form. Cattle, salt, shells, and cigarettes have all served as commodity money at various points in history. The advantage: value is inherent. Gold retains worth because it has real uses — jewellery, electronics, dentistry. Its supply is naturally limited. This restricts inflation: you cannot debase a gold coin simply by decree. The disadvantages: gold is heavy, hard to divide precisely, and dangerous to transport. Crucially, the supply of gold does not grow with the economy — in periods of rapid growth, a fixed money supply causes deflation (falling prices), which discourages spending and slows growth.
Fiat money: value from trust
Fiat money — from the Latin for "let it be done" — is currency declared to be legal tender by a government, with no intrinsic value. The pound, dollar, euro, and yen are all fiat currencies. Their value comes entirely from collective belief: people accept them because everyone else will accept them, backed by government authority and the legal requirement to accept them in settlement of debts.
The UK left the gold standard fully in 1931. The US ended its international link to gold in 1971, when President Nixon ended the ability of foreign governments to exchange dollars for gold at $35 per ounce. Since then, every major currency has been pure fiat.
Why governments prefer fiat
The critical advantage of fiat money is flexibility. When the economy contracts — as in 2008 and 2020 — governments and central banks can inject money to prevent collapse. Under a gold standard, this is structurally impossible: you cannot create money faster than your gold mines can dig. The 2008 crisis would very likely have become a second Great Depression without the ability to expand money supply rapidly.
Fiat money is backed by nothing except the collective belief that it will work — which turns out to be surprisingly robust, because as long as enough people trust it, it does.
The risks: inflation and hyperinflation
The same flexibility that makes fiat powerful can be abused. If a government prints too much money — as Zimbabwe did in the 2000s or the Weimar Republic in 1920s Germany — inflation becomes hyperinflation and the currency collapses. In Zimbabwe at its peak, prices doubled every 24 hours. In Germany in November 1923, a loaf of bread cost 200 billion marks. This is why assets like gold and Bitcoin attract interest as inflation hedges — both have limited supply by design, resisting the inflation risk inherent in fiat.