Economics 1968

The Tragedy of the Commons

Garrett Hardin

What is open to all and owned by none is grazed to ruin — by each user acting rationally.

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In depth · the introduction

Why does a shared fishing ground get emptied, while the fish in a private pond do not?

The big idea

Some things belong to everyone and no one — a grazing field the whole village uses, a fishery, the open air. Garrett Hardin’s claim was unsettling: such shared things tend to get wrecked, not by villains but by reasonable people doing the sensible thing. If I put one more cow on the common pasture, I get the whole benefit of that cow; the extra wear on the grass is split among everyone. So the smart move is always to add one more — and since everyone is equally smart, the grass is eaten to bare earth.

He called this “the tragedy of the commons,” and argued it had “no technical solution”: no cleverer fence or fertiliser fixes a problem that lives in the incentives themselves. The only real fixes change the rules of who may use the resource, and how.

How it came about

Hardin was an ecologist at the University of California, Santa Barbara. In 1968 he turned a society presidential lecture into a short essay for the journal Science. He was writing in the shadow of the post-war population boom and the dawning environmental movement — Rachel Carson’s Silent Spring had appeared six years earlier — and his real worry was the growth of human numbers, which he saw as the commons problem behind pollution and scarcity. The pasture was his way of making the logic unforgettable, and it worked: the phrase escaped into everyday speech and became one of the most-cited ideas in modern science.

Why it mattered

It gave a name and a clear picture to a problem that turns up wherever people share something they can’t easily fence: overfished seas, drained aquifers, polluted rivers, and now a warming atmosphere into which everyone is free to pour carbon. Once you can see the structure, you can look for the cure — and the cure is almost never “try harder” or “be less greedy.” It is changing the rules: ownership, quotas, permits, or shared agreements with teeth.

A way to picture it

Think of an all-you-can-eat buffet where the bill is split equally among everyone in the room. Each extra plate you take is delicious and, to you, nearly free — its cost is smeared across the whole table. So everyone over-orders, the food runs out, and the shared bill balloons. A meal you paid for alone, you would order sensibly. The difference isn’t your character; it’s who pays for the next plate.

Where it sits

Hardin’s pessimism is one pole of a long argument. Thomas Malthus (1798, in this Library) warned that population outruns resources; Hardin updated the worry for the age of pollution. At the other pole stands Elinor Ostrom (1990, also here), who went out and found communities that govern their commons sustainably for centuries — showing ruin is a risk, not a destiny. Between Adam Smith’s faith in markets and the case for the state, the commons marks the ground both can fail to cover.

The original document

Original source text

Garrett Hardin · Science, New Series, Vol. 162, No. 3859 (13 December 1968), pp. 1243–1248 · based on a presidential address to the Pacific Division of the AAAS, Utah State University, Logan, 25 June 1968.

The summary

Hardin opens by arguing that some problems admit no technical fix — no improvement in technique or yield will solve them, because the difficulty is one of values, not of means.

The population problem has no technical solution; it requires a fundamental extension in morality.

The pasture

To show why, he draws a now-famous picture of a grazing common shared by many herdsmen.

Picture a pasture open to all.

Each herdsman, he argues, rationally asks one question — and the arithmetic always points the same way:

What is the utility to me of adding one more animal to my herd?

The gain from the extra animal is his alone (a benefit of nearly +1); the cost — overgrazing — is shared among all the herdsmen (a fraction of −1). So the rational herdsman adds another animal, and another. Since each reasons alike, the conclusion is collective.

Therein is the tragedy. Each man is locked into a system that compels him to increase his herd without limit—in a world that is limited.

Ruin is the destination toward which all men rush, each pursuing his own best interest in a society that believes in the freedom of the commons. Freedom in a commons brings ruin to all.

From pasture to pollution and population

Hardin extends the same logic to pollution (the commons as a sink into which each discharges waste) and, centrally, to human population growth, which he regarded as the commons problem behind all the others. His remedy is not appeals to conscience — which he holds to be self-eliminating — but agreed-upon constraint, “mutual coercion, mutually agreed upon by the majority of the people affected.”

The remedy — and its shadow

Applied to population, Hardin reaches a conclusion many readers have since rejected:

Freedom to breed is intolerable.

(On honesty: Hardin’s later writing on population, immigration and aid carried coercive and, at times, explicitly racist views; this line is quoted not to endorse it but because the essay’s reception cannot be understood without it — see the Expert “limits” section.)

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Garrett Hardin · University of California, Santa Barbara · Science · 13 December 1968