The tool of statistical inference becomes available as the result of a self-imposed limitation of the universe of discourse. It is assumed that the available observations have been generated by a probability law or stochastic process about which some incomplete knowledge is available a priori …
It should be kept in mind that the sharpness and power of these remarkable tools of inductive reasoning are bought by willingness to adopt a specification of the universe in a form suitable for mathematical analysis.
Yes indeed — using statistics and econometrics to make inferences you have to make lots of (mathematical) tractability assumptions. And especially since econometrics aspires to explain things in terms of causes and effects, it needs loads of assumptions, such as e.g. invariance, additivity and linearity.
Limiting model assumptions in economic science always have to be closely examined since if we are going to be able to show that the mechanisms or causes that we isolate and handle in our models are stable in the sense that they do not change when we ‘export’ them to our ‘target systems,’ we have to be able to show that they do not only hold under ceteris paribus conditions. If not, they are of limited value to our explanations and predictions of real economic systems.
Unfortunately, real world social systems are usually not governed by stable causal mechanisms or capacities. The kinds of ‘laws’ and relations that econometrics has established, are laws and relations about entities in models that presuppose causal mechanisms being invariant, atomistic and additive. But — when causal mechanisms operate in the real world they mostly do it in ever-changing and unstable ways. If economic regularities obtain they do so as a rule only because we engineered them for that purpose. Outside man-made ‘nomological machines’ they are rare, or even non-existant.
So — if we want to explain and understand real-world economies we should perhaps be a little bit more cautious with using universe specifications ‘suitable for mathematical analysis’ …
What made phrenology so popular was what also made economics so popular at the time: it gave a rationale for a society based on Progress and also provided a blueprint for how this could be achieved. The phrenological doctrine, being so vague in its pronouncements, was highly malleable and could be used to justify whatever those in power needed justifying. So, for example, in 19th century England phrenology was used to justify laissez faire economic policies by emphasising unequal natural capacities amongst the population while in early 20th century Belgian Rwanda it was used to justify the supposed superiority of the Tutsis over the Hutus.
In my book The Reformation in Economics I take the position that modern economics is more similar to phrenology than it is to, say, physics. This is not at all surprising as it grew up in the same era and out of remarkably similar ideas. But what is surprising is that this is not widely noticed today. What is most tragic, however, is that there is much in economics that can and should be salvaged. While these positive aspects of economics probably do not deserve the title of ‘science’ they at least provide us with a rational toolkit that can be used to improve political and economic governance in our societies.
My recent research with Carine Nourry and Alain Venditti argues that while there are strong reasons for believing there are no free lunches left uneaten by bonus-hungry market participants, there are really no reasons for believing that this will lead to Pareto efficiency, except, perhaps, by chance …
In our model environment, booms and crashes occur simply as a consequence of the animal spirits of market participants. Why should we care if there are big movements in the asset markets? After all, the borrowers and lenders are rational and they have made bets with each other in full knowledge that these large asset movements might occur.
•The problem is that the next generation is unable to insure against swings in wealth that have a big influence on their lives.
Steve Davis and Till von Wachter (2011) have shown that the present value of lifetime income of new entrants to the labour market can differ substantially depending on whether their first job occurs in a boom or a recession. In our model, the lifetime income of the young can differ by as much as 20% across booms and slumps.
Given the choice, the young agents in our model would prefer to avoid the risk of a 20% variation in lifetime wealth. There is a feasible way of allocating resources that would insure them against this risk, but financial markets cannot achieve this allocation, except by chance. The inability of our children to trade in prenatal financial markets is sufficient to invalidate the first welfare theorem of economics.
In short, sunspots matter. And they matter in a big way.
Yes indeed. David Cass’ and Karl Shell’s ‘sunspots’ show that financial markets are far from Pareto efficient. And the day Roger Farmer is prepared to drop his residual mainstream infatuation with models building on assumptions of ‘complete financial markets,’ rational expectations, and households planning for infinite futures, his thought-provoking critique of mainstream economics will be even more forceful …
The WHO today warned of a virulent new virus affecting vulnerable groups in the Mid-West and Eastern USA. The outbreak, which began in the Mid-West’s extensive Great Lakes ‘Freshwater’ river system, has recently jumped the ‘Saltwater’ barrier, meaning that the entire population of its target species – ‘Mainstream’ economists – is now at risk.
Speaking on behalf of the WHO, Dr Cahuc explained that the virus works by turning off the one genetic marker that distinguishes this species from the rest of its genus, the Human Race. This is the so-called ‘Milton’ gene (Friedman 1953), which goes dormant in other Humans as they pass through puberty. Its inactivity reduces their imaginative capacity, making it impossible for them to continue believing in such endearing infantile fantasies as the Tooth Fairy and Santa Claus. While regrettable, this drop in imagination is necessary to prepare Humans for the adult phase of their existence …
The new virus – named ‘Reality’ – de-activates the Milton gene once more. ‘Consequently’, Dr Cahuc warned, ‘the very beliefs that define this unique species are at risk. Unless we are very careful, it may become extinct!’.
Unfortunately, there is as yet no known cure to this virus. ‘The WHO therefore recommends complete avoidance of “Reality” as the only effective strategy for those wishing to remain as Mainstream Economists’, Dr Cahuc concluded.
However, this strategy is made extremely difficult by one cunning characteristic of the Reality virus: after an initial phase of disorientation and distress, its sufferers begin to experience pleasure, and actually want to pass the virus on to others. ‘Its transmission mechanism is a particularly insidious aspect of this disease’, Dr Cahuc lamented.
Maintaining that economics is a science in the ‘true knowledge’ business, I remain a skeptic of the pretences and aspirations of ‘New Keynesian’ macroeconomics. So far, I cannot really see that it has yielded very much in terms of realist and relevant economic knowledge. And there’s nothing new or Keynesian about it.
‘New Keynesianism’ doesn’t have its roots in Keynes. It has its intellectual roots in Paul Samuelson’s ill-founded ‘neoclassical synthesis’ project, whereby he thought he could save the ‘classical’ view of the market economy as a (long run) self-regulating market clearing equilibrium mechanism, by adding some (short run) frictions and rigidities in the form of sticky wages and prices.
But — putting a sticky-price lipstick on the ‘classical’ pig sure won’t do. The ‘New Keynesian’ pig is still neither Keynesian nor new.
The rather one-sided emphasis of usefulness and its concomitant instrumentalist justification cannot hide that ‘New Keynesians’ cannot give supportive evidence for their considering it fruitful to analyze macroeconomic structures and events as the aggregated result of optimizing representative actors. After having analyzed some of its ontological and epistemological foundations, yours truly cannot but conclude that ‘New Keynesian’ macroeconomics on the whole has not delivered anything else than ‘as if’ unreal and irrelevant models.
The purported strength of New Classical and ‘New Keynesian’ macroeconomics is that they have firm anchorage in preference-based microeconomics, and especially the decisions taken by inter-temporal utility maximizing ‘forward-looking’ individuals.
To some of us, however, this has come at too high a price. The almost quasi-religious insistence that macroeconomics has to have microfoundations – without ever presenting neither ontological nor epistemological justifications for this claim – has put a blind eye to the weakness of the whole enterprise of trying to depict a complex economy based on an all-embracing representative actor equipped with superhuman knowledge, forecasting abilities and forward-looking rational expectations. It is as if – after having swallowed the sour grapes of the Sonnenschein-Mantel-Debreu-theorem – these economists want to resurrect the omniscient Walrasian auctioneer in the form of all-knowing representative actors equipped with rational expectations and assumed to somehow know the true structure of our model of the world.
And then, of course, there is that weird view on unemployment that makes you wonder on which planet those ‘New Keynesians’ live …
But these more recent writers like their predecessors were still dealing with a system in which the amount of the factors employed was given and the other relevant facts were known more or less for certain. This does not mean that they were dealing with a system in which change was ruled out, or even one in which the disappointment of expectation was ruled out. But at any given time facts and expectations were assumed to be given in a definite and calculable form; and risks, of which, tho admitted, not much notice was taken, were supposed to be capable of an exact actuarial computation. The calculus of probability, tho mention of it was kept in the background, was supposed to be capable of reducing uncertainty to the same calculable status as that of certainty itself …
Thus the fact that our knowledge of the future is fluctuating, vague and uncertain, renders Wealth a peculiarly unsuitable subject for the methods of the classical economic theory.
And this emphasis on the importance of uncertainty is not even mentioned in IS-LM ‘New Keynesianism’ …
Unless you have a PhD in economics, you probably think it uncontroversial to argue that we should be concerned about the unemployment rate. Those of you who have lost a job, or who have struggled to find a job on leaving school, college, or a university, are well aware that unemployment is a painful and dehumanizing experience. You may be surprised to learn that, for the past thirty-five years, the models used by academic economists and central bankers to understand how the economy works have not included unemployment as a separate category. In almost every macroeconomic seminar I attended, from 1980 through 2007, it was accepted that all unemployment is voluntary.
‘New Keynesian’ and New Classical microfounded dynamic stochastic general equilibrium models do not incorporate such a basic fact of reality as involuntary unemployment. Of course, working with microfounded representative agent models, this should come as no surprise. If one representative agent is employed, all representative agents are. The kind of unemployment that occurs is voluntary, since it is only adjustments of the hours of work that these optimizing agents make to maximize their utility. In this model world, unemployment is always an optimal choice to changes in the labour market conditions. Hence, unemployment is totally voluntary. To be unemployed is something one optimally chooses to be.
To Keynes it was an obvious and sad fact of the world that not all unemployment is voluntary. But obviously not so to New Classical and ‘New Keynesian’ economists.
In September 2003, Swedish citizens were asked if they wanted to join the eurozone. Of the more than 80 % of registered voters participating in the referendum close to 57 % said NO.
Yours truly participated actively in the fight against the euro — and it’s still something I’m immensely proud of.
New figures from Eurostat shows that the unemployment rate in many of the eurozone countries are still in double digits. This is of course totally and utterly unacceptable. Unemployment is not only an immense economic waste. It is also a cause of poverty. In a civilised society, everyone should have the right to work. The kind of austerity policies that the euro forces many countries to pursue, counteracts the goal of a full-employment society.
The celebrated optimism of traditional economic theory, which has led to economists being looked upon as Candides, who, having left this world for the cultivation of their gardens, teach that all is for the best in the best of all possible worlds provided we will let it well alone, is also to be traced, I think, to their having neglected to take account of the drag on prosperity which can be exercised by an insufficiency of effective demand.
John Maynard Keynes
Looking around in euro-land today one has to ask oneself: How much whipping can democracy take? How many more are going to get seriously hurt and ruined before we end this madness and put the euro where it belongs – in the dustbin of history!
- Dumb and dumber in modern macroeconomics
- Why Paul Krugman is no real Keynesian
- Dani Rodrik’s blind spot
- Robert Lucas, rational expectations, and the understanding of business cycles
- The blatant absence of empirical fit of macroeconomic models
- Non-ergodic economics, expected utility and the Kelly criterion
- The real debt problem
- Is macroeconomics for real?
- Please say after me – Sonnenschein-Mantel-Debreu
- Probaility and economics