What the Price Doesn’t Say

The Economists of Proof — Friedrich Hayek

Who knows what needs to be known to feed a city?

No one. Not the ministry, which receives the figures months late. Not the purchasing group, which knows its contracts but not the fields. Not the country’s largest retailer. The knowledge required — the state of this particular plot, last night’s frost, that truck’s breakdown, this grower’s moment of exhaustion — is scattered across thousands of minds, and it can never be gathered into one. No census moves fast enough, no administration has enough eyes.

That is the starting point of a fourteen-page article published in 1945, one that would become among the most cited in the entire history of the discipline: “The Use of Knowledge in Society,” by Friedrich Hayek.

The marvel

Hayek’s thesis rests on a reversal. The economic problem, he says, is not the one we assume — allocating known resources in the best possible way. It is a problem of knowledge: how to use knowledge that no one holds in full? And his answer is that the solution already exists, in plain sight, and always has: the price.

His example has remained famous. Somewhere in the world, a tin mine closes — or a new use for tin appears, it does not matter which. Without any of the parties involved needing to know why, the price rises. And that single number is enough: thousands of manufacturers economize on tin, engineers look for substitutes, prospectors reopen marginal deposits. Each of them saw only a price; all of them acted as if they knew what only an omniscient god could have known.

The price is a summary. It compresses into a single number everything the world knows about the scarcity of a thing — harvests, breakdowns, wars, fashions — and it circulates that compression faster and farther than any report ever could. It must be said without reservation: this is one of the most astonishing mechanisms an economist has ever described, and eighty years later no one has found anything better at doing what it does.

At doing what it does.

Because a summary, by definition, discards. That is even its function: to compress is to choose what to keep. The price transmits scarcity — admirably. It transmits neither quality, nor practice, nor path.

Two tomatoes at the same price on the same stall. One grew in living soil, thirty kilometers away, picked ripe yesterday. The other crossed a continent, ripening in the truck. The price is rigorously silent about the difference — not through failure, but by construction: it has only one number to say everything, and that number is already spoken for.

The first episode of this series showed what happens next. When the buyer cannot tell quality apart, he pays an average price; at the average price, the best producer sells at a loss and exits the market; average quality falls, the price follows, and the market spirals downward — this is Akerlof’s market for lemons. The two results fit together exactly: Hayek described the channel, Akerlof showed what happens to everything that does not fit through it. What the price cannot say eventually stops existing economically.

The missing market

The lazy conclusion would be: the price is imperfect. It is wrong, and Hayek would be right to sweep it aside — imperfect compared to what? The world price of a tomato does its job perfectly, and that job is to aggregate the scarcity of tomatoes.

The accurate conclusion is more unsettling: nothing is missing from the price. What is missing is a price. Verified practice, a proven path, attested quality have no price anywhere — no market quotes them, no signal carries them. Economists have a technical name for this: a missing market. And an attribute with no price does not circulate, whatever its real value — it stays in the head of whoever knows it, like the map in the sand.

The lesson of 1945 then says precisely what not to do. Faced with dispersed knowledge, the reflex is to centralize it: a data warehouse, a platform where everyone is asked to pour in what they know. This reflex has been tried, more than once, with considerable resources — and it has failed in series, always in the same way: everyone was supposed to contribute, no one found it worth their while, and the knowledge never came. Hayek could have written these obituaries eighty years in advance. Dispersed knowledge is not centralized. It is only mobilized by giving each person a local reason to share it — which is exactly what a price does, and exactly what a form will never do.

The Hayekian answer to the missing market is therefore neither a ministry of quality nor one more platform. It is the creation of the missing price: a second signal, alongside the first, that circulates what the first discards — and that rewards, at the very place where it resides, the knowledge it sets in motion.

The objection Hayek would raise

It is predictable, and it is serious: if buyers truly valued proof, the market would have already produced it. Its absence proves it is not worth its cost. This is the standard Hayekian argument against any claim to correct the market, and it deserves better than a shrug.

Two answers, and both are already in this series. The first: it is true at a given cost of description — and that cost has just collapsed. What once required a man and a notebook now fits into a sensor and a standard; a market that did not exist at the old cost can exist at the new one. Yesterday’s absence proved yesterday’s price, not today’s value.

The second is deeper: in the presence of information asymmetry, a missing market does not create itself. This is the most solid result in the whole series — Akerlof demonstrated it, and the Nobel that crowned it was not rewarding an opinion. The market for lemons does not repair itself: without a mechanism for proof, the quality seller cannot signal, so no one pays for quality, so no price for it is ever created. The second signal is not a correction of the market against Hayek. It is what was missing for the market for quality to exist — in the most Hayekian sense of the word: a place where dispersed knowledge finally finds its number.

Let us return to tin, one last time. The price will always tell us, better than any administration on earth, how scarce the tomato is this week. It will never tell us what it is, or where it gets what it is worth. This is not a flaw to fix: it is a place to fill. Two channels, two functions — and a market that tells the whole truth only when both are circulating.

The price says what it costs. What remains is to circulate what it is worth.

—

Friedrich Hayek, “The Use of Knowledge in Society,” American Economic Review, 1945. Episode 6 of the series “The Economists of Proof,” after Akerlof, Spence, Stiglitz, Coase, and Ostrom.