Tanti saluti delle Cinque Terre

31 July, 2018 at 18:40 | Posted in Varia | Leave a comment

 

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Il ritmo della passione

30 July, 2018 at 18:17 | Posted in Varia | Leave a comment

 

Der Zusammenhang zwischen Musikgeschmack und Intelligenz

30 July, 2018 at 16:26 | Posted in Statistics & Econometrics | 3 Comments

 

Still shining

28 July, 2018 at 22:50 | Posted in Varia | 1 Comment

Heard a couple of street guitarists play this classic outside Il Duomo di Milano earlier this evening. Still absolutely fabulous after all these years:

On tour again

24 July, 2018 at 13:53 | Posted in Varia | 1 Comment

Guest appearances in Hamburg, Zurich, Milan and Genoa.
Regular blogging will be resumed in August.

The state of ‘New Keynesian’ economics

24 July, 2018 at 13:46 | Posted in Economics | 1 Comment

nkThe standard NK [New Keynesian] model, like most of its predecessors in the RBC literature, represents an economy inhabited by an infinitely-lived representative household. That assumption, while obviously unrealistic, may be justified by the belief that, like so many other aspects of reality, the finiteness of life and the observed heterogeneity of individuals along many dimensions … can be safely ignored for the purposes of explaining aggregate fluctuations and their interaction with monetary policy, with the consequent advantages in terms of tractability …

There is a sense in which none of the extensions of the NK model described above can capture an important aspect of most financial crises, namely, a gradual build-up of financial imbalances leading to an eventual “crash” characterized by defaults, sudden-stops of credit flows, asset price declines, and a large contraction in aggregate demand, output and employment. By contrast, most of the models considered above share with their predecessors a focus on equilibria that take the form of stationary fluctuations driven by exogenous shocks. This is also the case in variants of those models that allow for financial frictions of different kinds and which have become quite popular as a result of the financial crisis … The introduction of financial frictions in those models often leads to an amplification of the effects of non-financial shocks. It also makes room for additional sources of fluctuations related to the presence of financial frictions … or exogenous changes in the tightness of borrowing constraints​ … Most attempts to use a version of the NK models to explain the “financial crisis,” however, end up relying on a large exogenous shock that impinges on the economy unexpectedly, triggering a large recession, possibly amplified by a financial accelerator mechanism embedded in the model. It is not obvious what the empirical counterpart to such an exogenous shock is.

Jordi Gali

Gali’s presentation sure raises important questions that serious economists ought to ask themselves. Using ‘simplifying’ tractability assumptions such as “infinitely-lived representative household,” rational expectations, common knowledge, additivity, ergodicity, etc — because otherwise they cannot ‘manipulate’ their models or come up with ‘rigorous ‘ and ‘precise’ predictions and explanations, does not exempt — ‘New Keynesian’ or not — economists from having to justify their modelling choices. Being able to ‘manipulate’ things in models cannot per se be enough to warrant a methodological choice. If economists do not come up with any other arguments for their chosen modelling strategy than Gali’s “advantages in terms of tractability,” it is certainly a just question to ask for clarification of the ultimate goal of the whole modelling endeavour.

Gali’s article underlines that the essence of mainstream economic theory is its almost exclusive use of a deductivist methodology. A methodology that is more or less used without a smack of argument to justify its relevance.

The theories and models that mainstream economists construct describe imaginary worlds using a combination of formal sign systems such as mathematics and ordinary language. The descriptions made are extremely thin and to a large degree disconnected to the specific contexts of the targeted system than one (usually) wants to (partially) represent. This is not by chance. These closed formalistic-mathematical theories and models are constructed for the purpose of being able to deliver purportedly rigorous deductions that may somehow by be exportable to the target system. By analyzing a few causal factors in their “laboratories” they hope they can perform “thought experiments” and observe how these factors operate on their own and without impediments or confounders.

Unfortunately, this is not so. The reason for this is that economic causes never act in a socio-economic vacuum. Causes have to be set in a contextual structure to be able to operate. This structure has to take some form or other, but instead of incorporating structures that are true to the target system, the settings made in economic models are rather based on formalistic mathematical tractability. In the models they appear as unrealistic assumptions, usually playing a decisive role in getting the deductive machinery to deliver “precise” and “rigorous” results. This, of course, makes exporting to real-world target systems problematic, since these models – as part of a deductivist covering-law tradition in economics – are thought to deliver general and far-reaching conclusions that are externally valid. But how can we be sure the lessons learned in these theories and models have external validity when based on highly specific unrealistic assumptions? As a rule, the more specific and concrete the structures, the less generalizable the results. Admitting that we in principle can move from (partial) falsehoods in theories and models to truth in real-world target systems do not take us very far unless a thorough explication of the relation between theory, model and the real world target system is made. If models assume representative actors, rational expectations, market clearing and equilibrium, and we know that real people and markets cannot be expected to obey these assumptions, the warrants for supposing that conclusions or hypothesis of causally relevant mechanisms or regularities can be bridged, are obviously non-justifiable. To have a deductive warrant for things happening in a closed model is no guarantee for them being preserved when applied to an open real-world target system.

Henry Louis Mencken once wrote that “there is always an easy solution to every human problem – neat, plausible and wrong.” And mainstream economics has indeed been wrong. Very wrong. Its main result, so far, has been to demonstrate the futility of trying to build a satisfactory bridge between formalistic-axiomatic deductivist models and real-world d target systems. Assuming, for example, perfect knowledge, instant market clearing and approximating aggregate behaviour with unrealistically heroic assumptions of “infinitely-lived” representative actors, just will not do. The assumptions made, surreptitiously eliminate the very phenomena we want to study: uncertainty, disequilibrium, structural instability and problems of aggregation and coordination between different individuals and groups.

The punch line is that most of the problems that mainstream economics is wrestling with, issues from its attempts at formalistic modelling per se of social phenomena. If scientific progress in economics – as Robert Lucas and other latter days mainstream economists seem to think – lies in our ability to tell “better and better stories” without considering the realm of imagination and ideas a retreat from real-world target systems reality, one would, of course, think our economics journal being filled with articles supporting the stories with empirical evidence. However, I would argue that the journals still show a striking and embarrassing paucity of empirical studies that (try to) substantiate these theoretical claims. Equally amazing is how little one has to say about the relationship between the model and real-world target systems. It is as though thinking explicit discussion, argumentation and justification on the subject not required. Mainstream economic theory is obviously navigating in dire straits.

If the ultimate criterion for success of a deductivist system is to what extent it predicts and cohere with (parts of) reality, modern mainstream economics seems to be a hopeless misallocation of scientific resources. To focus scientific endeavours on proving things in models is a gross misapprehension of what an economic theory ought to be about. Deductivist models and methods disconnected from reality are not relevant to predict, explain or understand real-world economic target systems. These systems do not conform to the restricted closed-system structure the mainstream modelling strategy presupposes.

Mainstream economic theory still today consists mainly of investigating economic models. It has since long given up on the real world and contents itself with proving things about thought up worlds. Empirical evidence still only plays a minor role in mainstream economic theory, where models largely function as substitutes for empirical evidence.

What is wrong with mainstream economics is not that it employs models per se, but that it employs poor models. They are poor because they do not bridge to the real world target system in which we live. Hopefully humbled by the manifest failure of its theoretical pretences, the one-sided, almost religious, insistence on mathematical deductivist modelling as the only scientific activity worthy of pursuing in economics will give way to methodological pluralism based on ontological considerations rather than “consequent advantages in terms of tractability.”

Intelligenz und Herkunft

24 July, 2018 at 09:05 | Posted in Varia | Leave a comment

 

Where modern macroeconomics went wrong

23 July, 2018 at 16:09 | Posted in Economics | 19 Comments

In issue 1-2 (2018) of Oxford Review of Economic Policy, the editors have invited some well-known contemporary mainstream macroeconomists (including e.g. Simon Wren-Lewis, Randall Wright, Olivier Blanchard, Ricardo Reis, Joseph Stiglitz) to give their views on how to rebuild macroeconomic theory for the future.

economist_cover_oh_fuck_september_2008Some of the contributions are interesting to read. Others — like Wren-Lewis and Blanchard — seem to think that we can basically just go on with our microfounded DSGE models and complement them with one or other structural econometric model (SEM). Two bads, however, do not add up to one good.

Joseph Stiglitz article on Where Modern Macroeconomics Went Wrong acknowledges that his approach “and that of DSGE models begins with the same starting point: the competitive equilibrium model of Arrow and Debreu.” That is, however, probably also the reason why Stiglitz’ suggestions for rebuilding macroeconomics don’t go far enough.

It’s strange that mainstream macroeconomists still stick to a general equilibrium paradigm more than forty years after the Sonnenschein-Mantel-Debreu theorem — SMD — devastatingly showed that it  is an absolute non-starter for building realist and relevant macroeconomics:

SMD theory means that assumptions guaranteeing good behavior at the microeconomic level do not carry over to the aggregate level or to qualitative features of the equilibrium …

24958274Given how sweeping the changes wrought by SMD theory seem to be, it is understandable that some very broad statements about the character of general equilibrium theory were made. Fifteen years after General Competitive Analysis, Arrow (1986) stated that the hypothesis of rationality had few implications at the aggregate level. Kirman (1989) held that general equilibrium theory could not generate falsifiable propositions, given that almost any set of data seemed consistent with the theory …

S. Abu Turab Rizvi

New Classical-Real Business Cycles-DSGE-New Keynesian microfounded macro models try to describe and analyze complex and heterogeneous real economies with a single rational-expectations-robot-imitation-representative-agent. That is, with something that has absolutely nothing to do with reality. And — worse still — something that is not even amenable to the kind of general equilibrium analysis that they are thought to give a foundation for since SMD unequivocally showed that there did not exist any condition by which assumptions on individuals would guarantee either stability or uniqueness of the equilibrium solution.

Opting for cloned representative agents that are all identical is of course not a real solution to the fallacy of composition that SMD points to. Representative agent models are — as I have argued at length here — rather an evasion whereby issues of distribution, coordination, heterogeneity — everything that really defines macroeconomics — are swept under the rug.

Of course, most macroeconomists know that to use a representative agent is a flagrantly illegitimate method of ignoring real aggregation issues. They keep on with their business, nevertheless, just because it significantly simplifies what they are doing. It reminds — not so little — of the drunkard who has lost his keys in some dark place and deliberately chooses to look for them under a neighbouring street light just because it is easier to see there.

General equilibrium is fundamental to economics on a more normative level as well. A story about Adam Smith, the invisible hand, and the merits of markets pervades introductory textbooks, classroom teaching, and contemporary political discourse. The intellectual foundation of this story rests on general equilibrium, not on the latest mathematical excursions. If the foundation of everyone’s favourite economics story is now known to be unsound — and according to some, uninteresting as well — then the profession owes the world a bit of an explanation.

Frank Ackerman

Almost a century and a half after Léon Walras founded general equilibrium theory, economists still have not been able to show that markets lead economies to equilibria. We do know that — under very restrictive assumptions — equilibria do exist, are unique and are Pareto-efficient. But — what good does that do? As long as we cannot show that there are convincing reasons to suppose there are forces which lead economies to equilibria — the value of general equilibrium theory is nil. As long as we cannot really demonstrate that there are forces operating — under reasonable, relevant and at least mildly realistic conditions — at moving markets to equilibria, there cannot really be any sustainable reason for anyone to pay any interest or attention to this theory.

A stability that can only be proved by assuming Santa Claus conditions is of no avail. Most people do not believe in Santa Claus anymore. And for good reasons — Santa Claus is for kids.

Continuing to model a world full of agents behaving as economists — ‘often wrong, but never uncertain’ — and still not being able to show that the system under reasonable assumptions converges to equilibrium (or simply assume the problem away), is a gross misallocation of intellectual resources and time.

Bourdieu on neoliberalism

23 July, 2018 at 08:55 | Posted in Economics | 2 Comments

neoEconomists may not necessarily share the economic and social interests of the true believers and may have a variety of individual psychic states regarding the economic and social effects of the utopia which they cloak with mathematical reason. Nevertheless, they have enough specific interests in the field of economic science to contribute decisively to the production and reproduction of belief in the neoliberal utopia. Separated from the realities of the economic and social world by their existence and above all by their intellectual formation, which is most frequently purely abstract, bookish, and theoretical, they are particularly inclined to confuse the things of logic with the logic of things.

These economists trust models that they almost never have occasion to submit to the test of experimental verification and are led to look down upon the results of the other historical sciences, in which they do not recognise the purity and crystalline transparency of their mathematical games, whose true necessity and profound complexity they are often incapable of understanding. They participate and collaborate in a formidable economic and social change. Even if some of its consequences horrify them (they can join the socialist party and give learned counsel to its representatives in the power structure), it cannot displease them because, at the risk of a few failures, imputable to what they sometimes call “speculative bubbles”, it tends to give reality to the ultra-logical utopia (ultra-logical like certain forms of insanity) to which they consecrate their lives.

Pierre Bourdieu

Erdoğan hat die Demokratie endgültig abgeschafft

22 July, 2018 at 12:46 | Posted in Politics & Society | Leave a comment

Am Sonntagabend sah ich Monteverdis Die Krönung der Poppea in der Berliner Staatsoper, eine mythische Geschichte aus dem Intrigenpalast von Kaiser Nero. Bei der Krönungsszene am Ende liegt die Hälfte der Helden in ihrem Blut am Boden. Anschließend ging ich zum Bebelplatz, wo die Nazis 1933 Bücher ins Feuer geworfen haben. Ich versuchte, mir diese Nacht der Bücherverbrennung vor 85 Jahren zu vergegenwärtigen …

erdogan-democracy-undermineAm Tag darauf kam im Fernsehen die “Krönung” des neuen “Kaisers” der Türkei. Erdoğan, durch Wahlen an die Macht gekommen, hatte die Kompetenzen des Parlaments auf das Kabinett übertragen lassen und die parlamentarische Demokratie abgeschafft. Während er begleitet von Böllerschüssen und Gebeten den Thron bestieg, trug die Hälfte des Landes Trauer. Seinem Mantra “Eine Heimat, ein Staat, eine Nation, eine Fahne” hatte er ein weiteres Glied hinzugefügt: “Ein Führer!

Zu den ersten Tätigkeiten des Präsidenten gehörte es, Staatstheater, Oper und Ballett seinem Amt zu unterstellen. Unwillkürlich musste ich an ein Interview von 1994 denken. Auf die Frage einer Kollegin, ob er Probleme damit hätte, ihr die Hand zu geben, wenn sie als Balletttänzerin vor ihm stünde, entgegnete Erdoğan: “Ich hätte Ihnen vor allem geraten, den Beruf zu wechseln. Denn was eine Balletttänzerin tut, worauf sie abzielt, ist offensichtlich. Einer der wichtigsten Zweige des Kulturimperialismus ist es, die Leute unter der Gürtellinie zu beschäftigen. Gott sei Dank haben meine Töchter nicht solche Träume.” Heute untersteht das türkische Ballett dieser Geisteshaltung.

Can Dündar/Die Zeit

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