Open Brainstorm with Steve Keen

Last night, we held a Brainstorm with Steve Keen and discussed his new book, Can We Avoid Another Financial Crisis? And his answer was clear: that depends upon what you mean by “we”, kemosabe. TL;DR: in a global context, no, we cannot avoid it, but it should be about half as bad as 2008. And we’ll probably get 6-12 months of warning from his model.

As usual, Professor Keen was brilliant, informative, and entertaining. And now that he’s embarked on a paper relating to David Ricardo and free trade, I don’t think he’ll object to me posting the email he sent me a few months ago when I asked him about the implications for free trade of the demand-based break between micro and macro caused by the Sonnenschein-Mantel-Debreu theorem. Or, as I memorably renamed it last night, Sonnensomething-Niederbopp-Whatever.

In this context the key point of the Sonnenschein-Mantel-Debreu theorem is not the failure to derive a demand curve, but the inability to represent the interests of everyone in a single country using a “Community Indifference Curve”, which is an essential part of the Hecksher-Ohlin model of free trade, which has of course supplanted Ricardo’s original model.

Samuelson’s defence of doing so is frankly comical, and also highlights one of the two key weaknesses of the model: it only works if income or wealth is compulsorily redistributed to equalise the “ethical worth” of every dollar earned/possessed, and he thought this was a reasonable assumption. From “Social Indifference Curves”, Paul Samuelson, 1956

  1. It is shown that the various defenses which have been offered for the use of community indifference curves are all open to some serious questioning.
  2. The Scitovsky community indifference contours are shown to be “minimum social requirements” contours of total goods needed to achieve a certain prescribed level of ordinal well-being for all. The dual properties of the Figures Ia and Ib, relating points in the commodity and ordinal-utility spaces, are demonstrated.
  3. By means of mathematical reasoning or by the demonstration of intersections of Scitovsky contours, a fundamental impossibility theorem is proved: Except where income elasticities are all unity and tastes are absolutely uniform for all, it is proved to be absolutely impossible to solve for unique market price ratios in function of market totals; hence, we must lack collective indifference curves capable of generating group demand.
  4. All this is shown to entail the nonoptimality of any shibboleth rule which once and for all and independently of changes in technology and taste data predetermines the initial distribution of income or endowments.
  5. Since most “individual” demand is really “family” demand, the argument can be made that such family demands have been shown to have none of the nice properties of modern consumption theory. However, if within the family there can be assumed to take place an optimal reallocation of income so as to keep each member’s dollar expenditure of equal ethical worth, then there can be derived for the whole family a set of well-behaved indifference contours relating the totals of what it consumes: the family can be said to act as if it maximizes such a group preference function.
  6. The same argument will apply to all of society if optimal reallocations of income can be assumed to keep the ethical worth of each person’s marginal dollar equal. By means of Hicks’s composite commodity theorem and by other considerations, a rigorous proof is given that the newly defined social or community indifference contours have the regularity properties of ordinary individual preference contours (nonintersection, convexity to the origin, etc.).

This is the key problem from the demand side: free trade is only universally of benefit to a given nation if the gains are shared; this requires redistribution mechanisms in addition to the market, which both don’t exist, and contradict the model of free competition if they were to be implemented.

The key problem for the supply side is easily stated: How do you turn a wine press into a spinning jenny (to use Ricardo’s examples). The standard model assumes the costless reallocation of capital between industries in response to a change in relative prices caused by reducing tariffs. But this is impossible. Capital is physical and attuned to specific industries. Free trade therefore makes obsolete some capital in a protected industry, while making that in a benefited industry more expensive, but not more productive.