"The knowledge that every problem has an answer, even and perhaps especially if that answer may be difficult to find, meets a deeply felt human need. For that reason, many people become obsessive about artificial worlds, such as computer games, in which they can see the connection between actions and outcomes. Many economists who pursue these approaches are similarly asocial. It is probably no accident that economics is by far the most male of the social sciences."
I agree with John Kay's description. I am less sure he has identified a fatal flaw. Yes, models are unrealistic - that's the point. A model that included everything wouldn't be a model, it would be reality. Simple models are good ones. But he is right, some people who use them have confused them with reality.
The Map is Not the Territory: An Essay on the State of Economics
by JOHN KAY
The reputation of economics and economists, never high, has been a victim of the crash of 2008. The Queen was hardly alone in asking why no one had predicted it. An even more serious criticism is that the economic policy debate that followed seems only to replay the similar debate after 1929. The issue is budgetary austerity versus fiscal stimulus, and the positions of the protagonists are entirely predictable from their previous political allegiances.
The doyen of modern macroeconomics, Robert Lucas, responded to the Queen’s question in a guest article in The Economist in August 2009. The crisis was not predicted, he explained, because economic theory predicts that such events cannot be predicted. Faced with such a response, a wise sovereign will seek counsel elsewhere.
But not from the principal associates of Lucas, who are even less apologetic. Edward Prescott, like Lucas, a Nobel Prize winner, began a recent address to a gathering of Laureates by announcing ‘this is a great time in aggregate economics’. Thomas Sargent, whose role in developing Lucas’s ideas has been decisive, is more robust still. Sargent observes that criticisms such as Her Majesty’s ‘reflect either woeful ignorance or intentional disregard of what modern macroeconomics is about’. ‘Off with his head’, perhaps. But before dismissing such responses as ridiculous, consider why these economists thought them appropriate.
In his lecture on the award of the Nobel Prize for Economics in 1995, Lucas described his seminal model. That model developed into the dominant approach to macroeconomics today, now called dynamic stochastic general equilibrium. In that paper, Lucas makes (among others) the following assumptions: everyone lives for two periods, of equal length, and works for one and spends in another; there is only one good, and no possibility of storage of that good, or of investment; there is only one homogenous kind of labour; there is no mechanism of family support between older and younger generations. And so on.
All science uses unrealistic simplifying assumptions. Physicists describe motion on frictionless plains, gravity in a world without air resistance. Not because anyone believes that the world is frictionless and airless, but because it is too difficult to study everything at once. A simplifying model eliminates confounding factors and focuses on a particular issue of interest. To put such models to practical use, you must be willing to bring back the excluded factors. You will probably find that this modification will be important for some problems, and not others – air resistance makes a big difference to a falling feather but not to a falling cannonball.
But Lucas and those who follow him were plainly engaged in a very different exercise, as the philosopher Nancy Cartwright has explained. The distinguishing characteristic of their approach is that the list of unrealistic simplifying assumptions is extremely long. Lucas was explicit about his objective – ‘the construction of a mechanical artificial world populated by interacting robots that economics typically studies’. An economic theory, he explains, is something that ‘can be put on a computer and run’. Lucas has called structures like these ‘analogue economies’, because they are, in a sense, complete economic systems. They loosely resemble the world, but a world so pared down that everything about them is either known, or can be made up. Such models are akin to Tolkien’s Middle Earth, or a computer game like Grand Theft Auto.
The knowledge that every problem has an answer, even and perhaps especially if that answer may be difficult to find, meets a deeply felt human need. For that reason, many people become obsessive about artificial worlds, such as computer games, in which they can see the connection between actions and outcomes. Many economists who pursue these approaches are similarly asocial. It is probably no accident that economics is by far the most male of the social sciences.
One might learn skills or acquire useful ideas through playing these games, and some users do. If the compilers are good at their job, as of course they are, the sound effects, events, and outcomes of a computer game resemble those we hear and see – they can, in a phrase that Lucas and his colleagues have popularised, be calibrated against the real world. But that correspondence does not, in any other sense, validate the model. The nature of such self-contained systems is that successful strategies are the product of the assumptions made by the authors. It obviously cannot be inferred that policies that work in Grand Theft Auto are appropriate policies for governments and businesses.
Yet this correspondence does seem to be what the proponents of this approach hope to achieve – and even claim they have achieved...
Read the full thing
While we are at it, here's an "anthropologist's view":
Life among the Econ
by Axel Leijonhufvud:
"The Econ tribe occupies a vast territory in the far North. Their land appears bleak and dismal to the outsider, and travelling through it makes for rough sledding; but the Econ, through a long period of adaptation, have learned to wrest a living of sorts from it. They are not without some genuine and sometimes even fierce attachment to their ancestral grounds, and their young are brought up to feel contempt for the softer living in the warmer lands of their neighbours. such as the Polscis and the Sociogs. Despite a common genetical heritage, relations with these tribes are strained-the distrust and contempt that the average Econ feels for these neighbours being heartily reciprocated by the latter-and social intercourse with them is inhibited by numerous taboos. The extreme clannishness, not to say xenophobia, of the Econ makes life among them difficult and perhaps even somewhat dangerous for the outsider. This probably accounts for the fact that the Econ have so far-not been systematically studied. Information about their social structure and ways of life is fragmentary and not well validated. More research on this interesting tribe is badly needed..."
Here's the pdf of the original 1973 journal article.
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