The Most Famous Lines in Economics, in Order

1776: Smith's Invisible Hand and the Butcher

Two of the most quoted lines in economics both come from Adam Smith. In The Wealth of Nations (1776) he writes that it is not from the benevolence of the butcher, the brewer, or the baker that we expect our dinner, but from their regard to their own interest — the classic statement that self-interested exchange, not goodwill, feeds a city. The same book contains the single appearance of the invisible hand in that work, in a passage arguing that a merchant who intends only his own security and gain is led by an invisible hand to promote an end which was no part of his intention. The phrase had already appeared once in The Theory of Moral Sentiments (1759). Both lines are genuine, but both are quoted far more often than Smith actually used the image, which has given it a centrality in his thought that the texts do not support.

1849: Carlyle Coins 'the Dismal Science'

The nickname that has followed economics for over a century was not coined by an economist and was not meant kindly. Thomas Carlyle, the Scottish essayist, called political economy the dismal science in an 1849 essay published in Fraser's Magazine, later reissued under a title using a racial slur. The context is important and frequently omitted: Carlyle was arguing for the reintroduction of slavery in the West Indies, and he applied the label partly because economists of the day, following the logic of markets and the moral universalism associated with the discipline, opposed slavery and supported emancipation. The popular story that Carlyle meant Malthusian population gloom is a later softening. The phrase was an insult from a defender of slavery aimed at a discipline whose conclusions pointed the other way, and that documented context is worth restoring whenever the phrase is used.

1867–1936: Marx, Marshall and the Rise of the Quotable Economist

Marx supplied slogans that outlived his economics: the closing call of the Communist Manifesto (1848, with Engels) that the workers have nothing to lose but their chains, and the principle from an 1875 critique, from each according to his ability, to each according to his needs. Alfred Marshall, by contrast, is remembered for a definition rather than a slogan — economics as the study of mankind in the ordinary business of life, from his Principles (1890) — and for the homely image of supply and demand as the two blades of a pair of scissors. This span is when economists became publicly quotable figures, their phrases detaching from the technical arguments that produced them and circulating on their own, a process that is exactly why so many of them are now misremembered.

1923: Keynes and 'the Long Run'

Keynes's most quoted sentence appears in A Tract on Monetary Reform (1923), not in the General Theory as is very commonly assumed. The full passage reads that the long run is a misleading guide to current affairs, because in the long run we are all dead, and that economists set themselves too easy a task if in tempestuous seasons they can only tell us that when the storm is long past the ocean is flat again. It is a methodological complaint about reassurances that markets will self-correct eventually, not a call to ignore the future or to spend recklessly — a misreading the compressed quotation invites. Keynes also coined animal spirits in the General Theory (1936) for the spontaneous urge to action behind investment, and described defunct economists as the hidden influence on practical men who believe themselves free of any intellectual influence.

1975: 'No Such Thing as a Free Lunch' Enters Economics

The phrase most associated with Milton Friedman was neither coined by him nor original to economics. There ain't no such thing as a free lunch circulated in American saloons and newspapers from at least the early twentieth century, referring to the free food offered to drinking customers whose cost was folded into the drinks. It appears in Robert Heinlein's 1966 novel The Moon Is a Harsh Mistress. Friedman popularised it for economics, using it as the title of a 1975 book, and it became shorthand for opportunity cost — every choice forgoes an alternative. He did not claim to have invented it. Attributing the coinage to Friedman is one of the most common errors in economics quotation, and the honest version credits him with the popularisation and leaves the origin where it belongs, with an older and anonymous tradition.