Say’s Law: An Overview and Bibliography

I think an overview is in order in light of Robert Murphy’s confusing post here, which seems (as far as I can see) to agree that a “general glut” or failure of aggregate demand is possible, contrary to the extreme form of Say’s law, but in a bizarre argument invoking “present and future goods” and the notion that “leisure is a present consumption good.”

Say’s law of course is defined in various ways, but the two main definitions are as follows:

(1) Say’s Identity
According to Baumol (1977: 146), this

“is the assertion that no one ever wants to hold money for any significant amount of time, so that, as a result, every offer (supply) of a quantity of goods automatically constitutes a demand for a bundle of some other items of equal market value”; and

(2) Say’s Equality
Again, according to Baumol (1977: 146), Say’s Equality

“admits the possibility of (brief) periods of disequilibrium during which the total demand for goods may fall short of the total supply, but maintains that there exist reliable equilibrating forces that must soon bring the two together.”

The issue of how Jean-Baptiste Say (1767–1832) himself defined the law is complicated by the fact that Say produced various editions of his Treatise on Political Economy and different treatments of the law, as follows:

(1) the first edition of Say’s Traité d’économie politique (1803; or the Treatise on Political Economy in English) has only a brief and not properly formulated version of the law;

(2) the second edition of Traité d’économie politique/Treatise on Political Economy (published in 1814) has the first proper formulation of Say’s law (Baumol 1977: 147).

(3) a summary of the law appears in Say’s Catechism of Political Economy (1816: 103–105).

(4) in the fourth edition of Traité d’économie politique/Treatise on Political Economy (1819) Say revised his remarks on the law in important ways (Heertje 2004: 41).

It seems widely accepted today that Say’s role in formulating the law is overrated. That is, both Thweatt (1979: 92–93) and Baumol (2003: 46) conclude that Adam Smith was in fact the real father of what is recognisably Say’s law in Classical economics, with the major work in developing the idea conducted by James Mill (1808), not necessarily Jean-Baptiste Say himself.

So let us look at how Say’s law was formulated by the Classical economists, as defined by Thomas Sowell (1994: 39–41). Sowell defines it as these propositions:

“(1) The total factor payments received for producing a given volume (or value) of output are necessarily sufficient to purchase that volume (or value) of output [an idea in James Mill].

(2) There is no loss of purchasing power anywhere in the economy. People save only to the extent of their desire to invest and do not hold money beyond their transactions need during the current period [James Mill and Adam Smith].

(3) Investment is only an internal transfer, not a net reduction, of aggregate demand. The same amount that could have been spent by the thrifty consumer will be spent by the capitalists and/or the workers in the investment goods sector [John Stuart Mill].

(4) In real terms, supply equals demand ex ante [= “before the event”], since each individual produces only because of, and to the extent of, his demand for other goods. (Sometimes this doctrine was supported by demonstrating that supply equals demand ex post.) [James Mill.]

(5) A higher rate of savings will cause a higher rate of subsequent growth in aggregate output [James Mill and Adam Smith].

(6) Disequilibrium in the economy can exist only because the internal proportions of output differ from consumer’s preferred mix—not because output is excessive in the aggregate” [Say, Ricardo, Torrens, James Mill] (Sowell 1994: 39–41).

Why is Say’s law false?

One fatal flaw is the underlying assumption, which is clear in the work of Jean-Baptiste Say himself, that money cannot provide direct utility:

“For, after all, money is but the agent of the transfer of values. Its whole utility has consisted in conveying to your hands the value of the commodities, which your customer has sold, for the purpose of buying again from you; and the very next purchase you make, it will again convey to a third person the value of the products you may have sold to others.” (Say 1821a: 164–165).

This is made clear to us by Say’s statement: “[sc. the] whole utility [sc. of money] has consisted in conveying to your hands the value of the commodities.” This is a world where nobody holds money for significant periods of time because money can have no utility, except in what it can purchase in terms of commodities. But that is not the world we live in. We live in a world of uncertainty. In the face of uncertainty, money can yield direct utility (Graziani 2003: 11). Therefore people can and do hold money for significant periods!

First, “Say’s Identity” simply ignores the reality of people holding money without purchasing goods and services because of uncertainty (Keynes’s precautionary motive), or what Keynes called idle money hoards. It also ignores the spending of money on secondary financial or real asset markets or holding of money idle for this reason (Keynes’s speculative motive).

In any real world economy, money from income streams from production, either to capitalists or workers, can become diverted to asset markets and may not be spent on goods. For this reason alone, Say’s law is a grossly unrealistic picture of market economies. Capitalists themselves have subjective expectations about the future and the future profitability of investment, and when their expectations are shattered, they will not necessarily invest out of retained earnings.

Secondly, a further serious problem with both versions of Say’s law is the assumption of universal or near universal flexprice markets, when vast numbers of industrial, service, retail and even capital goods markets are fixprice, and administered prices are the norm. In modern capitalist economies, supply and demand are equated by changes in employment and output, not by flexible prices. (And also the whole simplistic economic model of Say’s law does not have a place for endogenous money and banks that create credit money for investment.)

Lastly, as a matter of historical interest, eventually it appears that Jean-Baptiste Say actually repudiated the strong form of Say’s law we call “Say’s Identity” in his letters to Malthus, and seems to have admitted the existence of failures of aggregate demand.

More detailed discussion is here:

“The Myth of Say’s Law,” October 7, 2010.

“F. H. Hahn in a Candid Moment on Neo-Walrasian Equilibrium ,” January 29, 2011.

“Say’s Law Presupposes Aggregate Demand as a Meaningful Concept,” May 28, 2011.

“Say Repudiated Say’s Law,” December 1, 2011.

“Jean Baptiste Say on Failures of Aggregate Demand,” December 1, 2011.

“Jean-Baptiste Say and “Say’s Law,” September 14, 2012.

“The Origin of Say’s Law in Adam Smith and James Mill,” September 14, 2012.

“Bibliography on Say’s Law,” September 16, 2012.

“A Note on Prices and Say’s Law,” December 11, 2012.

“World GDP versus Total Value of Financial Asset Market Exchanges,” February 21, 2013.

I also reproduce my extended bibliography on Say’s law below.

BIBLIOGRAPHY

Anderson, William L. 2009. “Say’s Law and the Austrian Theory of the Business Cycle,” Quarterly Journal of Austrian Economics 12.2: 47–59.

Aspromourgos, Tony. 2009. The Science of Wealth: Adam Smith and the Framing of Political Economy. Routledge, London.

Balassa, Bela A. 1959. “John Stuart Mill and the Law of Markets,” Quarterly Journal of Economics 73.2: 263–274.

Baumol, William J. 1977. “Say’s (at Least) Eight Laws, or What Say and James Mill May Really Have Meant,” Economica n.s. 44.174: 145–161.

Baumol, William J. 1999. “Retrospectives: Say’s Law,” Journal of Economic Perspectives 13.1: 195–204.

Baumol, William J. 2003. “Retrospectives: Say’s Law,” in S. Kates (ed.), Two Hundred Years of Say’s Law: Essays on Economic Theory’s Most Controversial Principle, Edward Elgar Pub, Cheltenham and Northampton, Mass. 39–49.

Becker, Gary and William J. Baumol. 1952. “The Classical Economic Theory: The Outcome of the Discussion,” Economica 19: 355–376.

Blaug, M. 1996. Economic Theory in Retrospect (5th edn). Cambridge University Press, Cambridge.

Blaug, Mark. 1997. “Say’s Law of Markets: What did it mean and Why should We Care?,” Eastern Economic Journal 23.2: 231–235.

Clower, Robert W. and Leijonhufvud, Axel. 1973. “Say’s Principle, What It Means and Doesn’t Mean,” Intermountain Economic Review 4: 1–16.

Clower, Robert W. and Leijonhufvud, Axel. 1984. “Say’s Principle, What it Means and Doesn’t Mean,” in Donald A. Walker (ed.), Money and Markets: Essays by Robert W. Clower. Cambridge University Press, Cambridge. 145–165.

Cottrell, Allin. 1998. “Keynes, Ricardo, Malthus and Say’s Law,” in James C.W. Ahiakpor (ed.), Keynes and the Classics Reconsidered. Kluwer Academic, Boston, Mass. and London. 63–75.

“Debunking Economics, Part VIII: Macroeconomics, or Applied Microeconomics?,” Unlearning Economics, 26 August, 2012.
http://unlearningeconomics.wordpress.com/2012/08/26/debunking-economics-part-viii-macroeconomics-or-applied-microeconomics/

Gootzeit, M. 2003. “Savings, Hoarding and Say’s Law,” in S. Kates (ed.), Two Hundred Years of Say’s Law: Essays on Economic Theory’s Most Controversial Principle. Edward Elgar, Cheltenham and Northampton, Mass. 168–186.

Gordon, B. J. 1965. “Say’s Law, Effective Demand, and the Contemporary British Periodicals, 1820–1850,” Economica 32: 438–446.

Graziani, A. 2003. The Monetary Theory of Production. Cambridge University Press, Cambridge.

Groenewegen, P. D. 1977. The Economics of A. R. J. Turgot. Martinus Nijhoff, The Hague.

Heertje, A. 2004. “On Say’s Law,” in Tony Aspromourgos and John Lodewijks (eds.), History and Political Economy. Essays in Honour of P.D. Groenewegen. Routledge, London. 44–56.

Hollander, S. 2005. “Review of Two Hundred Years of Say’s Law: Essays on Economic Theory’s Most Controversial Principle,” History of Political Economy 37.2: 382–385.

Horwitz, Steven. 2003. “Say’s Law of Markets: An Austrian Appreciation,” in S. Kates (ed.), Two Hundred Years of Say’s Law: Essays on Economic Theory’s Most Controversial Principle. Elgar, Cheltenham, UK and Northampton, Mass. 82–98.

Hutt, William Harold. 1974. A Rehabilitation of Say’s Law. Ohio U.P., Athens, Ohio.

Johnson, Ivan C. 2001. “A Reappraisal of the Say’s Law Controversy,” Quarterly Journal of Austrian Economics 4.4: 25–53.

Jonsson, Petur O. 1995. “On the Economics of Say and Keynes’ Interpretation of Says’s Law,” Eastern Economic Journal 21.2: 147–155.

Jonsson, Petur O. 1997. “On Gluts, Effective Demand, and the True Meaning of Say’s Law,” Eastern Economic Journal 23.2: 203–218.

Jonsson, Petur O. 1998. “Keynes, Ricardo, Malthus and Say’s Law: Comment,” in James C.W. Ahiakpor (ed.), Keynes and the Classics Reconsidered. Kluwer Academic, Boston, Mass. and London.75–84.

Kates, Steven. 1994. “The Malthusian Origins of the General Theory or How Keynes came to write a Book about Say’s Law and Effective Demand,” History of Economics Review 21: 10–20.

Kates, Steven. 1995. “Crucial Influences on Keynes’s Understanding of Say’s Law,” History of Economics Review 23: 74–82.

Kates, Steven. 1996. “Keynes, Say’s Law and the Theory of the Business Cycle,” History of Economics Review 25: 119–126.

Kates, Steven. 1997. “A Discussion of Say’s Law: The Outcome of the Symposium,”Eastern Economic Journal 23.2: 237–239.

Kates, Steven. 1997. “On the True Meaning of Say’s Law,” Eastern Economic Journal 23.2: 191–202.

Kates, Steven. 2002. “Economic Management and the Keynesian Revolution: The Policy Consequences of the Disappearance of Say’s Law,” International Journal of Applied Economics and Econometrics 10.3: 463–479.

Kates, Steven (ed.). 2003. Two Hundred Years of Say’s Law: Essays on Economic Theory’s Most Controversial Principle, Edward Elgar Pub, Cheltenham; Northampton, Mass.

Kates, Steven. 2005. “‘Supply Creates Its Own Demand’: A Discussion of the Origins of the Phrase and of its Adequacy as an Interpretation of Say’s Law of Markets,” History of Economics Review 41: 49–60.

Kates, Steven. 2007. “Mill, McCracken and the Modern Interpretation of Say’s Law,” History of Economics Review 46: 32–38.

Kates, Steven. 2008. “A Letter from Keynes to Harlan McCracken dated 31st August 1933: Why the Standard Story on the Origins of the General Theory needs to be Rewritten,” History of Economics Review 47: 39–53.

Kates, Steven. 2010. “Why Your Grandfather’s Economics was better than yours: On the Catastrophic Disappearance of Say’s Law,” Quarterly Journal of Austrian Economics 13.4: 3–28.

Keen, S. 2003. “Nudge Nudge, Wink Wink, Say No More,” in S. Kates (ed.), Two Hundred Years of Say’s Law: Essays on Economic Theory’s Most Controversial Principle. Elgar, Cheltenham, UK and Northampton, Mass. 199–209.
http://www.debtdeflation.com/blogs/wp-content/uploads/papers/KeenNudgeNudgeWinkWinkSayNoMore.pdf

Kent, Richard J. 2005. “Keynes and Say’s Law,” History of Economics Review 41: 61–76.

Lange, O. 1942. “Say’s Law: A Restatement and Criticism,” in O. Lange, F. McIntyre and T. O. Matema (eds), Studies in Mathematical Economics and Econometrics: In Memory of Henry Schultz. University of Chicago Press, Chicago. 49–68.

Lange, Oskar. 1994. “Say’s Law: A Restatement and Criticism,” in Tadeusz Kowalik (ed.), Economic Theory and Market Socialism: Selected Essays of Oskar Lange. Elgar, Aldershot, U.K. 213–232.

Mill, James. 1808. Commerce Defended. An Answer to the Arguments by which Mr. Spence, Mr. Cobbett, and Others, have Attempted to Prove that Commerce is not a Source of National Wealth. C. and R. Baldwin, London.

Mises, L. 2005 [1950], “Lord Keynes and Say’s Law,” Mises Daily, April 25, 2005, http://mises.org/daily/1803

Say, Jean Baptiste. 1803. Traité d’économie politique, ou, Simple exposition de la manière dont se forment, se distribuent et se consomment les richesses (1st edn.). De Chapelet, Paris.

Say, Jean Baptiste. 1814. Traité d’économie politique, ou, Simple exposition de la manière dont se forment, se distribuent et se consomment les richesses (2nd edn.). Antoine-Augustin Renouard, Paris.

Say, J. B. 1816. Catechism of Political Economy, or, Familiar Conversations on the Manner in which Wealth is Produced, Distributed, and Consumed in Society (trans. J. Richter). Sherwood, Neely, and Jones, London.

Say, Jean Baptiste. 1817. Traité d’économie politique, ou, Simple exposition de la manière dont se forment, se distribuent et se consomment les richesses (3rd edn.). Chez Deterville, Paris.

Say, Jean Baptiste. 1819. Traité d’économie politique, ou, Simple exposition de la manière dont se forment, se distribuent et se consomment les richesses (4th edn.). Deterville, Paris.

Say, Jean Baptiste. 1821. A Treatise on Political Economy, or, The Production, Distribution, and Consumption of Wealth (trans. from 4th edn by C.R. Prinsep with notes by the translator, with a translation of the introduction and additional notes by C. C. Biddle). Wells and Lilly, Boston.

Say, Jean Baptiste. 1821a. A Treatise on Political Economy, or, The Production, Distribution, and Consumption of Wealth (trans. from 4th edn by C.R. Prinsep). Longman, Hurst, Rees, Orne And Brown, London.

Say, J. B. 1821b. Letters to Mr. Malthus: On Several Subjects of Political Economy, and on the Cause of the General Stagnation of Commerce. To Which is added A Catechism of Political Economy, Sherwood, Neely, and Jones, London.

Say, Jean Baptiste. 1826. Traité d’économie politique, ou, Simple exposition de la manière dont se forment, se distribuent et se consomment les richesses (5th edn.). Rapilly, Paris.

Shoul, B. 1957. “Karl Marx and Say’s Law,” Quarterly Journal of Economics 71.4: 611–629.

Skinner, A. S. 1967. “Say’s Law: Origins and Content,” Economica 34: 153–166.

Silva, Antonio Carlos Macedo e. 2004. “From Say’s Law to Keynes, from Keynes to Walras’s Law: Some Ironies in the History of Economic Thought,” in L. Randall Wray and Mathew Forstater (eds.). Contemporary Post Keynesian Analysis. Edward Elgar, Cheltenham, UK and Northampton, Mass. 310–332.

Skinner, A. S. 1969. “Of Malthus, Lauderdale and Say’s Law, Lauderdale and Say’s Law,” Scottish Journal of Political Economy 16.2: 177–195.

Smith, A. 1811. An Inquiry into the Nature and Causes of the Wealth of Nations (11 edn; vol. 1), Oliver D. Cooke, Hartford.

Sowell, T. 1972. Say’s Law: An Historical Analysis. Princeton University Press, Princeton, N.J.

Sowell, T. 1974. Classical Economics Reconsidered. Princeton University Press, Princeton, N.J. and London.

Sowell, T. 1994. Classical Economics Reconsidered (2nd ed.). Princeton University Press, Princeton, N.J.

Spengler, Joseph J. 1945. “The Physiocrats and Say’s Law of Markets,” Journal of Political Economy 53: 193–211, 317-347.

Thweatt, W. O. 1979. “Early Formulators of Say’s Law,” Quarterly Review of Economics and Business 19: 79–96.

Thweatt, W. O. 1980. “Baumol and James Mill on ‘Say’s’ Law of Markets,” Economica n.s. 47.188: 467–469.

Jean Baptiste Say on Failures of Aggregate Demand

In modern formulations of Say’s law (or the “law of markets”), there are two main variants of it, as follows:

(1) Say’s Identity
According to Baumol (1977: 146), this

“is the assertion that no one ever wants to hold money for any significant amount of time, so that, as a result, every offer (supply) of a quantity of goods automatically constitutes a demand for a bundle of some other items of equal market value.”

(2) Say’s Equality
Again, according to Baumol (1977: 146), Say’s Equality

“admits the possibility of (brief) periods of disequilibrium during which the total demand for goods may fall short of the total supply, but maintains that there exist reliable equilibrating forces that must soon bring the two together.

Say’s Identity requires that no failures of aggregate demand can occur, as money is not held for significant periods of time and factor payments from aggregate supply are spent in aggregate demand (either in consumption or investment). Thus in particular commodity markets there might be excess supply, but overall there is “zero value of the sum of excess demands” (Kates 2003: 45). It appears that James Mill and John Ramsay McCulloch both used Say’s Identity and Say’s Equality in their writings (Blaug 1996: 150).

There is a question here about whether Jean Baptiste Say ever expressed his “law of markets” as Say’s Identity. This is complicated by the fact that there was more than one edition of his Treatise on Political Economy. The second edition of the Treatise on Political Economy was published in 1814 and has a revised version of Say’s law (Baumol 1977: 147), while in the first edition the law of markets is not nearly so complete. It was only in the second edition of the Treatise on Political Economy (1814) that Say’s discussion is identifiable as a “form of a type of Say’s equality, i.e., supply and demand are always equated by a rapid and powerful equilibration mechanism” (Baumol 1977: 159). Indeed, Jean Baptiste Say even criticised Ricardo for using a version of the law of markets we would recognise as Say’s Identity (Blaug 1996: 150). The second version of the law of markets – Say’s Equality – is obviously a far weaker version of it, for it admits the possibility of short term failures of aggregate demand, even if a long run inequality between aggregate supply and demand is denied.

A relevant passage by Jean Baptiste Say on this issue occurs in one of his letters to Malthus:

“Mr. Ricardo insists that, notwithstanding taxes and other charges, there is always as much industry as capital employed; and that all capital saved is always employed, because the interest is not suffered to be lost. On the contrary, many savings are not invested, when it is difficult to find employment for them, and many which are employed are dissipated in ill-calculated undertakings. Besides, Mr. Ricardo is completely refuted not only by what happened to us in 1813, when the errors of Government ruined all commerce, and when the interest of money fell very low, for want of good opportunities of employing it; but by our present circumstances, when capitals are quietly sleeping in the coffers of their proprietors. The bank of France alone possesses 223 millions of specie in its chests, more than double the amount of its notes in circulation, and six times what it would be prudent to reserve for the ordinary course of its payments.” (Say 1821: 49; it was also published in New Monthly Magazine, Volume 14 [1820, October 1], p. 368ff.).

What we have here is:

(1) a recognition that money savings will not necessarily be invested in capital goods and that an aggregate demand failure has occurred;

(2) “many savings are not invested,” a rudimentary insight not far removed from Keynes’s theory of liquidity preference.

All that needed to be added was an analysis of the role of demand for money used in speculation on secondary financial asset markets for liquid assets as a store of value and subjective expectations in the investment decision.

BIBLIOGRAPHY
Baumol, W. J. 1977. “Say’s (at Least) Eight Laws, or What Say and James Mill May Really Have Meant,” Economica n.s. 44.174: 145–161.

Blaug, M. 1996. Economic Theory in Retrospect (5th edn). Cambridge University Press, Cambridge.

Kates, S. (ed.), 2003. Two Hundred Years of Say’s Law: Essays on Economic Theory’s Most Controversial Principle. Edward Elgar Pub, Cheltenham ; Northampton, Mass.

Say, J. B. 1821. Letters to Mr. Malthus: On Several Subjects of Political Economy, and on the Cause of the General Stagnation of Commerce. To Which is added A Catechism of Political Economy. Sherwood, Neely, and Jones, London.