Say made his name as the leading French political economist of his era with the publication of the Traité d'économie politique (1803) which went through many editions, revisions, and translations during his lifetime. The economic ideas which are most closely associated with his name are "Say's law" of markets (crudely formulated sometimes as "supply creates its own demand", or more broadly understood as the idea that producers, by nature of finding markets for and selling their own goods, generate income they can spend on other goods in the economy), the vital role played by the entrepreneur in economic activity, the contribution of "non-material" goods (such as services, human capital, and institutions) to the creation of wealth, and an early formulation of the theory of rent-seeking.
Say was also a keen popularizer of economic ideas, writing several works in dialogue form in order to teach liberal economic ideas to a broader audience at a time when economic nationalism and socialism were becoming more popular. One of his last major works, the Cours complet d'économie politique pratique (1828-9), was an attempt to broaden the scope of political economy away from the preoccupation with the production of wealth, by examining the moral, political, and sociological requirements of a free society and how they inter-related with the study of political economy. In other words, he wished to return political economy to its Smithian roots.
Say's family originated in Nîmes but had to flee to Geneva in the late 17th century when the state ended the policy of toleration towards Protestants. They returned in the mid-18th century to Lyon where Say's father became a merchant. The family intended Say and his brother Horace to continue in the family business and, to this end, the two brothers were sent to London to learn how modern commerce was done. They learnt this and English as well. Say's fluency in English meant that, when he came across a copy of Smith's Wealth of Nations (which had still not been translated into French) while working in a life insurance office, he was able to quickly absorb its contents.
When the French Revolution broke out, Say was swept up in events: he stopped working for Mirabeau's journal the Courrier de Provence to volunteer to fight and saw service in Champagne in 1792-93; he got married only to find his family's moderate wealth made him a target of the Terror before hyper-inflation wiped out most of what they had; finally, he was appointed editor of the journal of the liberal-minded "Idéologues" La Décade philosophique, littéraire, et politique for which he wrote articles on political economy from 1794-99.
Say's practical business experience and his knowledge of current economic policy led to his appointment in 1799 to the Tribunat where he served on the finance committee. It was in this context that the idea of a treatise on political economy was hatched and the first of eventually six editions appeared in 1803. Say's Treatise even came to the attention of First Consul Napoleon who, over dinner with Say, suggested a new edition should be published which more explicitly supported the government's unpopular fiscal policies. Say's blunt refusal to serve the interests of Napoleon and his constant opposition to the profligate spending of the government in the finance committee led to his dismissal from the Tribunat.
The next stage of Say's career was a return to the commercial world. Say relocated his family to Auchy in Pas-de-Calais where he set up a cotton spinning plant using the latest machinery from England. After eight quite successful years in business employing between 400-500 people in his factory, Say sold up and returned to Paris in 1813. He was convinced that French economic policy was going to result in economic collapse: the continental system which excluded British goods from the Continent, the issuing of government licenses for business, the increasing tariffs on imported cotton, and the difficulties of trading in wartime, were all stifling French industry.
The publication of the second edition of the Treatise on Political Economy in 1814 brought Say again to the attention of the government which employed him to travel to England on a fact finding mission to discover the secret of English economic growth and to report on the impact of the revolutionary wars on the British economy. Say also used the trip to make contact with British philosophical radicals and political economists such as James Mill, Jeremy Bentham and Ricardo. Part of his report was published in the pamphlet "De l'Angleterre et des Anglais" (1814). It contains a devastating critique of the economic impact of war on ordinary British working people and the use of the Bank of England to pay the costs of war by depreciating the money and creating public debt which would take decades to pay back.
Only after the defeat of Napoleon and the Restoration of the Bourbon monarchy was the pre-eminent French political economist of his day able to get a job teaching economics in Paris, first at the Athénée, then a chair in "industrial economics" at the Conservatoire des Arts et Métiers (the expression "political economy" was still regarded as somewhat radical and subversive), and finally the first chair in political economy at the Collège de France. Although he was a notoriously bad lecturer, reading directly from his manuscripts, he published a considerable amount in the remaining 17 years of his life. Numerous popular works on political economy appeared, along with several revised editions of the Treatise on Political Economy, a series of polemical letters written to Malthus, and a lengthy and unjustly neglected Cours complet d'économie politique pratique (1828-9).
Works by J. B. Say
Say, Jean-Baptiste, Traité d'économie politique, ou simple exposition dela maniÈre dont se forment, se distribuent et se consomment lesrichesses (1st edition 1803, Paris: Deterville). Online at http://gallica.bnf.fr/scripts/ConsultationTout.exe?O=N005672&E=0
Say, Jean-Baptiste, A Treatise on Political Economy. Translated from the 4th edition of the French by C. R. Prinsep, M.A. (New American Edition by Clement C. Biddle, LL.D. Philadelphia: Lippincott, Grambo & Co., 1855).
Say, Jean-Baptise, Cours complet d'économie politique pratique; ouvragedestiné à mettre sous les yeux des hommes d'état, des propriétairesfonciers et les capitalistes, des savans, des agriculteurs, desmanufacturiers, des négocians, et en général de tous les citoyens, l'économie des sociétés (Paris: Rapilly, 1828-9), 6 vols. Online at http://gallica.bnf.fr/scripts/ConsultationTout.exe?E=0&O=N005673
Say, Jean-Baptiste, Oeuvres diverses contenant: Catéchisme d'économiepolitique, fragments et opuscules inédits, correspondance générale, Olbie, Petit Volume, Mélanges de morale et de litérature' précédéesd'une Notice historique sur la vie et les travaux de l'auteur, Avec desnotes par Ch. Comte, E. Daire et Horace, Say (Paris: Guillaumin, 1848). Online at http://gallica.bnf.fr/scripts/ConsultationTout.exe?E=0&O=N005675
Works about J. B. Say
Hart, David M., Class Analysis, Slavery and the Industrialist Theory of History in French Liberal Thought, 1814-1830: The Radical Liberalism of Charles Comte and Charles Dunoyer (unpublished Ph.D., King's College Cambridge, 1994). Online version http://www.arts.adelaide.edu.au/personal/DHart/ClassicalLiberalism/ComteDunoyer/index.html
Sowell, Thomas, Say's Law: An Historical Introduction. PrincetonUniversity Press, 1972.
Weinburg, Mark, "The Social Analysis of Three Early 19th Century French Liberals: Say, Comte, and Dunoyer", Journal of Libertarian Studies, 2 no.1 (1978): 45-63.