Say’s Law and the law of markets are not the same

I have belatedly come to realise that Say’s Law is not the law of markets. How weird is that, after all these years. I have put the following up on the SHOE website as a continuation of my previous post L’offre crée même la demande. Hollande, as a result of the bitter experiences in trying to manage the French economy, now has a better grip on our fundamental economic principles than pretty well the whole of the economics profession.

There are a number of facts that are relevant in any discussion of Say’s Law which I thought I might set out. What I find something of a problem is the common assumption that Say’s Law refers to something that was believed during the early parts of the nineteenth century and was of little significance thereafter. No discussion ever seems to get past Malthus, Say and Mill in looking at what was an embedded principle right up until 1936.

The first thing that might be noted is that the term “Say’s Law” is not classical in origin but was consciously invented by Fred Manville Taylor and introduced into general economic discourse with the publication of his Principles of Economics text in 1921. Before Taylor no one called this association of demand with previous supply “Say’s Law”. Taylor introduced the term because he thought economic theory needed to identify one of its most important underlying principles. The ironies of what followed next are too obvious for comment.

This continuous fixation on the early classical economists has had a number of unfortunate consequences. The first is that economists are always returning to Say as if he provided the definitive statement on Say’s Law. He did not. If you want the point of origin, it is in James Mill in his Commerce Defended published in 1807. Here is the passage that matters, although the whole of his discussion is well worth the effort:

“No proposition however 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.”

The final sentence should be familiar but is not the actual origins of the specific words used by Keynes.

It is also important to appreciate James Mill’s role since I see his statement not only as exactly right, but he wrote his book in response to an argument in which too much saving and too little demand were seen as the causes of recession. This was the first instance in which an argument that economies are driven by demand was rejected. Mill was saying an economy could not be stimulated from the demand side. That was the point of Say’s Law, and still is.

This nameless principle was universally accepted by the mainstream. But if you would like to find Say’s Law as clearly stated as it is possible to find it in the classical literature, this is David Ricardo writing to Malthus just after the commencement of the General Glut debate in 1820. Malthus said the post-Napoleonic recessions had been caused by too much saving and too little demand. To this, Ricardo replied:

“Men err in their productions, there is no deficiency of demand.”

That’s it. Say’s Law. Recessions are caused by mis-directed production, not deficient demand. This was the foundation for the entire theory of the cycle that would develop over the following century. It is the disappearance of the theory of the cycle that may be the greatest loss economists have experienced because of the General Theory.

There is then this. At the end of the General Glut debate in 1848, John Stuart Mill published his Principles of Political Economy, which included his fourth proposition on capital. This may be the most enigmatic statement ever made by a great economist, but if you want to see the principle behind Say’s Law, whether you agree with it or not, this is what Mill wrote:

“Demand for commodities is not demand for labour.”

Or as we might put it today, an economic stimulus will not create jobs. This is a statement whose reasoning is perfectly clear to me. I teach it to my students and it is in my text and few ever have any trouble with it. Described in 1876 as “the best test of a sound economist”, in my view it still is. It was a conclusion that policy makers accepted right through until the 1930s and perhaps even for a while after. But it was an enduring concept.

So I take you back to Francois Hollande. What he said in French was this:

“Le temps est venu de régler le principal problème de la France : sa production. Oui, je dis bien sa production. Il nous faut produire plus, il nous faut produire mieux. C’est donc sur l’offre qu’il faut agir. Sur l’offre ! Ce n’est pas contradictoire avec la demande. L’offre crée même la demande.”

This is the whole thing in my free translation:

“The time has come to work through the number one problem in France: which is production. Yes, that’s what I said, production. We must produce more, we must produce better. Hence, it is upon supply that we must concentrate. On supply! This is not in opposition to demand. Supply actually creates demand.”

It is true the point Hollande makes takes you back to J.-B. Say, David Ricardo and James and John Stuart Mill, all of whom are, of course, classical. But he also takes you back to Fred Taylor whose book was published only a few years before the General Theory, where he was trying to state what every economist of his own generation knew and accepted. Today, so far as aggregate demand goes, we are all Keynesians now, with some very few exceptions.

And while we’re at it, you might also ask yourself how Taylor’s very much twentieth century phrase ended up in The General Theory. The standard story of the trek from the Treatise to the General Theory has a lot of gaps, even after the hundred million words that have been devoted to explaining what the General Theory means and how it came to be written.

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