The Properties of Money

Money isn’t one thing — it’s a job, and some goods do that job far better than others. Over millennia, societies converged on the same short list of properties. Score any candidate against them and the winners are obvious.

Scarcity

It must be hard to produce more. If anyone can make it cheaply, it floods the market and its value evaporates. Sea shells worked as money — until ships arrived by the boatload. Good money is costly or impossible to inflate.

Portability

You must be able to move value easily. Cattle are wealth you have to walk; a fortune in gold fits in a pocket. The more value you can carry with less effort, the better the money.

Divisibility

It must split into small units without losing value, so you can pay for a coffee or a house with the same money. A diamond can’t be halved without ruining it; gold can be melted into any amount.

Store of Value

It should hold purchasing power over time, so effort saved today can be spent years from now. This is really the payoff of scarcity and not perishing together: something rare that doesn’t decay lets you move value into the future.

Fungibility

Every unit must be interchangeable with every other. One ounce of pure gold equals any other ounce. If each unit is unique — like a painting or a plot of land — you can’t use it as a smooth medium of exchange.

Perishability

Good money must not perish. It has to survive time and handling — grain rots, fruit spoils, iron rusts, so none of them can hold savings. Gold does not tarnish or corrode: coins pulled from 2,000-year-old shipwrecks look brand new. The less a good decays, the better it carries value into the future.

Unit of Account

Once a good is widely used, everything gets priced in it — and it becomes the common ruler for measuring and comparing value. This is what finally kills the barter explosion of exchange rates: one price per good.

Power and Control

Whoever issues and controls the money holds enormous power — so good money should be something people can verify and hold for themselves, without asking permission. Counterfeit-resistance protects the honest; self-custody protects you from anyone who would seize, freeze, or debase it. Who controls a society’s money is one of the deepest questions in history — a thread we’ll follow from here on.

No good is perfect

Almost nothing scores full marks on every property at once. Cattle store value but aren’t portable or divisible. Shells are portable and durable but not scarce. Salt is divisible but perishes and is easy to find. The history of money is a long search for the good that scores highest across all of them at the same time.

For most of human history, one material came closest on every axis at once — which is why, again and again, independent civilisations that had never met all converged on the same answer. In the next lesson you can test that for yourself.

Next: put the whole periodic table to the test, one property at a time, and watch the elements fall away until only the monetary metals remain.

Key takeaways

Good money scores well across scarcity, portability, divisibility, fungibility, not perishing, being a unit of account, and resisting outside control.
Almost nothing is perfect on every axis at once — monetary history is the long search for the best all-round good.
Scarcity and durability together are what make something a reliable store of value.

Check yourself

Which property means every unit is interchangeable with every other?

Why do cattle make poor money despite storing real value?

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