Friday, September 14, 2012

The Origin of Say’s Law in Adam Smith and James Mill

Consider these passages from Adam Smith’s An Inquiry into the Nature and Causes of the Wealth of Nations (11 edn; 1811):
“In all countries where there is tolerable security, every man of common understanding will endeavour to employ whatever stock he can command, in procuring either present enjoyment or future profit. If it is employed in procuring present enjoyment, it is a stock reserved for immediate consumption. If it is employed in procuring future profit, it must procure this profit, either by staying with him, or by going from him. In the one case it is a fixed, in the other it is a circulating capital. A man must be perfectly crazy who, where there is tolerable security, does not employ all the stock which he commands, whether it be his own, or borrowed of other people, in some one or other of those three ways.” (Smith 1811: 198).

“What is annually saved is as regularly consumed as what is annually spent, and nearly in the same time too; but it is consumed by a different set of people. That portion of his revenue which a rich man annually spends is, in most cases consumed by idle guests, and menial servants, who leave nothing behind them in return for their consumption. That portion which he annually saves, as for the sake of the profit it is immediately employed as a capital, is consumed in the same manner, and nearly in the same time too, but by a different set of people, by labourers, manufacturers, and artificers, who re-produce with a profit the value of their annual consumption. His revenue, we shall suppose, is paid him in money. Had he spent the whole, the food, clothing, and lodging, which the whole could have purchased, would have been distributed among the former set of people. By saving a part of it, as that part is for the sake of the profit immediately employed as a capital either by himself or by some other person, the food, clothing, and lodging, which may be purchased with it, are necessarily reserved for the latter. The consumption is the same, but the consumers are different” (Smith 1811: 240).
Here we have the clear idea that money saved is spent again on capital goods investment and consumed by a different set of people: those to whom the invested money has now become income.

According to Smith, savings are “immediately employed as a capital” and thus consumed. That is to say, money not spent on consumption will be invested in capital goods projects and done so relatively quickly.

This we have here a version of Say’s law, at least as it was formulated by some of the later Classical economists.

Let us look at how Say’s law was formulated by the Classical economists, as defined by Thomas Sowell (1994: 39–41):
(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).
Proposition 6 – that individual markets can be in disequilibrium, but the overall demand, including demand for commodities not fulfilled, is balanced with the value of aggregate supply – does not explicitly appear in Adam Smith, as far as I am aware.

Yet both propositions (2) and (3) appear to be quite clearly in Adam Smith already.

James Mill in his treatise Commerce Defended (1807) developed the ideas in Adam Smith and those he found in the first edition of Say’s Traité d’économie politique (1803). We can quote from Mill’s Commerce Defended:
“No proposition in political [economy] seems to be more certain than this which I am going to announce, how paradoxical soever it may at first sight appear; and if it be true, none undoubtedly can be deemed of more importance. The production of commodities creates, and is the one and universal cause which creates a market for the commodities produced. Let us but consider what is meant by a market.

Is any thing else understood by it than that something is ready to be exchanged for the commodity which we would dispose of? When goods are carried to market what is wanted is somebody to buy. But to buy, one must have wherewithal to pay. It is obviously therefore the collective means of payment which exist in the whole nation that constitute the entire market of the nation. But wherein consist the collective means of payment of the whole nation? Do they not consist in its annual produce, in the annual revenue of the general mass of its inhabitants? But if a nation’s power of purchasing is exactly measured by its annual produce, as it undoubtedly is; the more you increase the annual produce, the more by that very act you extend the national market, the power of purchasing and the actual purchases of the nation. Whatever be the additional quantity of goods therefore which is at any time created in any country, an additional power of purchasing, exactly equivalent, is at the same instant created; so that a nation can never be naturally overstocked either with capital or with commodities; as the very operation of capital makes a vent for its produce.

Thus to recur to the example which we have already analyzed; fresh goods to the amount of £5,500 were prepared for the market in consequence of the application of the £5000 saved by the landholder. But what then? have we not seen that the annual produce of the country was increased; that is, the market of the country widened, to the extent of £5,500, by the very same operations? Mr. Spence in one place advises his reader to consider the circumstances of a country in which all exchange should be in the way of barter, as the idea of money frequently tends to perplex. If he will follow his own advice on this occasion, he will easily perceive how necessarily production creates a market for produce. When money is laid out of the question, is it not in reality the different commodities of the country, that is to say, the different articles of the annual produce, which are annually exchanged against one another? Whether these commodities are in great quantities or in small, that is to say, whether the country is rich or poor, will not one half of them always balance the other? and is it not the barter of one half of them with the other which actually constitutes the annual purchases and sales of the country? Is it not the one half of the goods of a country which universally forms the market for the other half, and vice versa? And is this a market that can ever be overstocked? Or can it produce the least disorder in this market whether the goods are in great or in small quantity? All that here can ever be requisite is that the goods should be adapted to one another; that is to say, that every man who has goods to dispose of should always find all those different sorts of goods with which he wishes to supply himself in return.

What is the difference when the goods are in great quantity and when they are in small? Only this, that in the one case the people are liberally supplied with goods, in the other that they are scantily; in the one case that the country is rich, in the other that it is poor: but in the one case, as well as in the other, the whole of the goods will be exchanged, the one half against the other; and the market will always be equal to the supply. Thus it appears that the demand of a nation is always equal to the produce of a nation. This indeed must be so; for what is the demand of a nation? The demand of a nation is exactly its power of purchasing. But what is its power of purchasing? The extent undoubtedly of its annual produce. The extent of its demand therefore and the extent of its supply are always exactly commensurate. Every particle of the annual produce of a country falls as revenue to somebody. But every individual in the nation uniformly makes purchases, or does what is equivalent to making purchases, with every farthing’s worth which accrues to him. All that part which is destined for mere consumption is evidently employed in purchases. That too which is employed as capital is not less so. It is either paid as wages to labourers, who immediately buy with it food and other necessaries, or it is employed in the purchase of raw materials. The whole annual produce of the country, therefore, is employed in making purchases. But as it is the whole annual produce too which is offered to sale, it is visible that the one part of it is employed in purchasing the other; that how great soever that annual produce may be it always creates a market to itself; and that how great soever that portion of the annual produce which is destined to administer to reproduction, that is, how great soever the portion employed as capital, its effects always are to render the country richer, and its inhabitants more opulent, but never to confuse or to overload the national market. I own that nothing appears to me more completely demonstrative than this reasoning.

It may be necessary, however, to remark, that a nation may easily have more than enough of any one commodity, though she can never have more than enough of commodities in general. The quantity of any one commodity may easily be carried beyond its due proportion; but by that very circumstance is implied that some other commodity is not provided in sufficient proportion. What indeed is meant by a commodity's exceeding the market? Is it not that there is a portion of it for which there is nothing that can be had in exchange. But of those other things then the proportion is too small. A part of the means of production which had been applied to the preparation of this superabundant commodity, should have been applied to the preparation of those other commodities till the balance between them had been established. Whenever this balance is properly preserved, there can be no superfluity of commodities, none for which a market will not be ready. This balance too the natural order of things has so powerful a tendency to produce, that it will always be very exactly preserved where the injudicious tampering of government does not prevent, or those disorders in the intercourse of the world, produced by the wars into which the inoffending part of mankind are plunged, by the folly much more frequently than by the wisdom of their rulers.

This important, and as it appears demonstrative doctrine, affords a view of commerce which ought to be very consolatory to Mr. Spence. It shews that a nation always has within itself a market equal to all the commodities of which it can possibly have to dispose; that its power of purchasing is always equivalent to its power of producing, or at least to its actual produce; and that as it never can be greater, so it never can be less. Foreign commerce, therefore, is in all cases a matter of expediency rather than of necessity. The intention of it is not to furnish a vent for the produce of the industry of the country, because that industry always furnishes a vent for itself. The intention of it is to exchange a part of our own commodities for a part of the commodities which we prefer to our own of some other nation; to exchange a set of commodities which it peculiarly suits our country to produce for a set of commodities which it peculiarly suits that other country to produce. Its use and advantage is to promote a better distribution, division and application of the labour of the country than would otherwise take place, and by consequence to render it more productive. It affords us a better, a more convenient and more opulent supply of commodities than could have been obtained by the application of our labour within ourselves, exactly in the same manner as by the free interchange of commodities from province to province within the same country, its labour is better divided and rendered more productive.” (Mill 1808 [1807]).
Both Thweatt (1979: 92–93) and Baumol (2003: 46) conclude that Adam Smith was in fact the father of what is recognisably Say’s law in Classical economics, with the major work in developing the idea conducted by James Mill, not necessarily Jean-Baptiste Say.


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.

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

Baumol, W. 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; Northampton, Mass. 39–49.

Mill, James. 1808 [1807]. 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.

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. 1994. Classical Economics Reconsidered, Princeton University Press, Princeton, N.J.

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


  1. You should read Aspromourgos. He's a Sraffian that touches especifically about this issue. I would claim that in Smith there's everything. Say's Law and effective demand as well.

    1. Do you have a citation of this work by Aspromourgos?

      Or do you mean this:

      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.

    2. Mainly this one:

      There are some chapters scattered in the web. He's a great economist.