From Lars Syll

Ce qui fait l’unité de la discipline est plutôt l’identification causale, c’est-à-dire un ensemble de méthodes statistiques qui permettent d’estimer les liens de cause à effet entre un facteur quelconque et des résultats économiques. Dans cette perspective, la démarche scientifique vise à reproduire in vivo l’expérience de laboratoire, où l’on peut distinguer aisément la différence de résultat entre un groupe auquel on administre un traitement et un autre groupe semblable qui n’est quant à lui pas affecté.

Les outils statistiques permettraient aux économistes d’appliquer cette méthode en dehors du laboratoire, y compris à l’histoire et à tout autre sujet. Là encore, il faudrait considérablement nuancer ce constat. Mais, il ne me semble pas aberrant de dire que si, pour

## Articles by Lars Pålsson Syll

## Is economics nothing but a library of models?

5 days agoIs economics nothing but a library of models?

Chameleons arise and are often nurtured by the following dynamic. First a bookshelf model is constructed that involves terms and elements that seem to have some relation to the real world and assumptions that are not so unrealistic that they would be dismissed out of hand. The intention of the author, let’s call him or her “Q,” in developing the model may be to say something about the real world or the goal may simply be to explore the implications of making a certain set of assumptions … If someone skeptical about X challenges the assumptions made by Q, some will say that a model shouldn’t be judged by the realism of its assumptions, since all models have assumptions that are unrealistic …

Chameleons are

## Chebyshev’s and Markov’s Inequality Theorems

6 days agoChebyshev’s and Markov’s Inequality Theorems

Chebyshev’s Inequality Theorem — named after Russian mathematician Pafnuty Chebyshev (1821-1894) — states that for a population (or sample) at most 1/k2 of the distribution’s values can be more than k standard deviations away from the mean. The beauty of the theorem is that although we may not know the exact distribution of the data — e.g. if it’s normally distributed — we may still say with certitude (since the theorem holds universally) that there are bounds on probabilities!

Another beautiful result of probability theory is Markov’s inequality (after the Russian mathematician Andrei Markov (1856-1922)):

If X is a non-negative stochastic variable (X ≥ 0) with a finite expectation value E(X), then for every

## Apache

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Read More »## The empirical turn in economics

8 days agoThe empirical turn in economics

Ce qui fait l’unité de la discipline est plutôt l’identification causale, c’est-à-dire un ensemble de méthodes statistiques qui permettent d’estimer les liens de cause à effet entre un facteur quelconque et des résultats économiques. Dans cette perspective, la démarche scientifique vise à reproduire in vivo l’expérience de laboratoire, où l’on peut distinguer aisément la différence de résultat entre un groupe auquel on administre un traitement et un autre groupe semblable qui n’est quant à lui pas affecté.

Les outils statistiques permettraient aux économistes d’appliquer cette méthode en dehors du laboratoire, y compris à l’histoire et à tout autre sujet. Là encore, il faudrait considérablement nuancer ce constat. Mais, il

## Weekend combinatorics (II)

9 days agoHow many permutations exist of the ten digits (0-9) that either begin with”123″, contain “56” in the 6th & 7th positions, or end with “789”?

Read More »## Knowledge and growth

10 days agoIf you have an apple and I have an apple and we exchange these apples then you and I will each have one apple.

But if you have an idea and I have an idea and we exchange these ideas, then each of us will have two ideas.

George Bernard Shaw

Adam Smith once wrote that a really good explanation is “practically seamless.” Is there any such theory within one of the most important fields of social sciences — economic growth?

In Paul Romer’s Endogenous Technological Change (1990) knowledge is made the most important driving force of growth. Knowledge (ideas) are presented as the locomotive of growth — but as Allyn Young, Piero Sraffa and others had shown already in the 1920s, knowledge is also something that has to do with increasing returns to scale and therefore not really

## On models and simplicity

10 days agoFrom Lars Syll

When it comes to modelling yours truly does see the point emphatically made time after time by e. g. Paul Krugman about simplicity — at least as long as it doesn’t impinge on our truth-seeking. ‘Simple’ macroeconomic models may of course be an informative heuristic tool for research. But if practitioners of modern macroeconomics do not investigate and make an effort of providing a justification for the credibility of the simplicity assumptions on which they erect their building, it will not fulfil its tasks. Maintaining that economics is a science in the ‘true knowledge’ business, yours truly remains a sceptic of the pretences and aspirations of ‘simple’ macroeconomic models and theories. So far, I can’t really see that e. g. ‘simple’ microfounded models have yielded

## Gimme Some Lovin

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Read More »## On models and simplicity

14 days agoOn models and simplicity

When it comes to modelling yours truly does see the point emphatically made time after time by e. g. Paul Krugman about simplicity — at least as long as it doesn’t impinge on our truth-seeking. ‘Simple’ macroeconomic models may of course be an informative heuristic tool for research. But if practitioners of modern macroeconomics do not investigate and make an effort of providing a justification for the credibility of the simplicity assumptions on which they erect their building, it will not fulfil its tasks. Maintaining that economics is a science in the ‘true knowledge’ business, yours truly remains a sceptic of the pretences and aspirations of ‘simple’ macroeconomic models and theories. So far, I can’t really see that e. g.

Read More »## Macroeconomics and the Friedman-Savage ‘as if’ logic

16 days agoFrom Lars Syll

An objection to the hypothesis just presented that is likely to be raised by many … is that it conflicts with the way human beings actually behave and choose. … Is it not patently unrealistic to suppose that individuals … base their decision on the size of the

expected utility?

While entirely natural and under-

standable, this objection is not strictly relevant … The hypothesis asserts rather that, in making a particular class of decisions, individuals behave as if they calculated and compared expected utility and as if they knew the odds. The validity of this assertion … depend solely on whether it yields sufficiently accurate predictions about the class of decisions

with which the hypothesis deals.

M Friedman & L J Savage

‘Modern’ macroeconomics — Dynamic Stochastic

## How to prove things

18 days agoHow to prove things

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Great lecture series.

Yours truly got Solow’s book when he was studying mathematics back in the 80s.

Now in its 6th edition, it’s better than ever.

## Lacrimosa

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Read More »## Macroeconomics and the Friedman-Savage ‘as if’ logic

18 days agoMacroeconomics and the Friedman-Savage ‘as if’ logic

An objection to the hypothesis just presented that is likely to be raised by many … is that it conflicts with the way human beings actually behave and choose. … Is it not patently unrealistic to suppose that individuals … base their decision on the size of the

expected utility?

While entirely natural and under-

standable, this objection is not strictly relevant … The hypothesis asserts rather that, in making a particular class of decisions, individuals behave as if they calculated and compared expected utility and as if they knew the odds. The validity of this assertion … depend solely on whether it yields sufficiently accurate predictions about the class of decisions

with which the hypothesis

## The dangers of using unproved assumptions

20 days agoFrom Lars Syll

The unpopularity of the principle of organic unities shows very clearly how great is the danger of the assumption of unproved additive formulas. The fallacy, of which ignorance of organic unity is a particular instance, may perhaps be mathematically represented thus: suppose f(x) is the goodness of x and f(y) is the goodness of y. It is then assumed that the goodness of x and y together is f(x) + f(y) when it is clearly f(x + y) and only in special cases will it be true that f(x + y) = f(x) + f(y). It is plain that it is never legitimate to assume this property in the case of any given function without proof.

J. M. Keynes “Ethics in Relation to Conduct” (1903)

Since econometrics doesn’t content itself with only making optimal predictions, but also aspires

## In state of emergency

21 days agoIn state of emergency

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Koncerten i S:t Pauli kyrka tidigare i kväll var för yours truly en av årets musilkaliska höjdpunkter.

Har ni möjlighet så missa inte koncerten (gratis) i Allhegonakyrkan i Lund i morgon kl. 19.00!

## Tentamen

22 days agoYours truly har rykte om sig att vara en krävande tentator. Det stämmer nog.

Men det finns alltid de som haft det ‘värre’ …

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## Ett sista glas

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En gigant i svensk musik har gått ur tiden.

Sven-Bertil Taube (1934-2022).

R.I.P.

## The dangers of using unproved assumptions

22 days agoThe dangers of using unproved assumptions

The unpopularity of the principle of organic unities shows very clearly how great is the danger of the assumption of unproved additive formulas. The fallacy, of which ignorance of organic unity is a particular instance, may perhaps be mathematically represented thus: suppose f(x) is the goodness of x and f(y) is the goodness of y. It is then assumed that the goodness of x and y together is f(x) + f(y) when it is clearly f(x + y) and only in special cases will it be true that f(x + y) = f(x) + f(y). It is plain that it is never legitimate to assume this property in the case of any given function without proof.

J. M. Keynes “Ethics in Relation to Conduct” (1903)

Since econometrics doesn’t content itself with only

Read More »## Fyra år med väderspänning

24 days agoFyra år med väderspänning

FN:s generalsekreterare säger att världen står i brand och att det pågår en klimatkris. Men flera sverigedemo- krater i riksdagen håller inte med, visar en enkät som SVT Nyheter gjort. Av de 108 ledamöter som svarat håller nästan alla helt eller delvis med FN- chefen. Sex av åtta från SD som svarat uppger att de “inte alls håller med” eller “delvis inte håller med”. SD-ledaren Jimmie Åkesson är skeptisk till att vi befinner oss i en klimatkris. -Jag har inte sett något vetenskapligt stöd för att det är så här och nu, säger han till SVT.

SVT Text TV

Man tager sig för pannan.

Vi kommer väl tyvärr alla att få lida av väderspänning de närmsta åren …

## Gendarmenmarkt (personal)

25 days agoWith loved one in one of our favourite spots in Berlin.

Read More »## Diskret matematik

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Bra föreläsningsserie från Chalmers! När jag själv läste matematik i Lund på 80-talet tyckte jag bäst om kurserna i diskret matematik. Mycket logik och problem av ‘tankenötskaraktär’. Och kul hjärngympa att lägga några timmar på när man vill pausa lite från schackspel och korsord …

## The Binomial and Poisson distributions (student stuff)

25 days ago## Den goda viljan

28 days ago.[embedded content]

Bille Augusts och Ingmar Bergmans mästerverk. Och med Stefan Nilssons musik, det vackraste och mest suggestiva i filmmusikväg som någonsin gjorts.

## Weekend combinatorics

29 days agoThinking of spending an extended weekend at his summer residence, yours truly wanted to take five of his favourite books with him. On my bookshelf are five books by Strindberg and four by Shakespeare. I thought of bringing with me at least two of the Strindberg volumes. In how many ways can I do this?

Read More »## Leontief and the sorry state of economics

November 2, 2022From Lars Syll

Page after page of professional economic journals are filled with mathematical formulas leading the reader from sets of more or less plausible but entirely arbitrary assumptions to precisely stated but irrelevant theoretical conclusions …

Year after year economic theorists continue to produce scores of mathematical models and to explore in great detail their formal properties; and the econometricians fit algebraic functions of all possible shapes to essentially the same sets of data without being able to advance, in any perceptible way, a systematic understanding of the structure and the operations of a real economic system.

Wassily Leontief

Mainstream economics is, as noted by Leontief, hopelessly irrelevant to the understanding of the real world, and the main reason

## What’s the use of economics?

November 2, 2022What’s the use of economics?

The simple question that was raised during a recent conference … was to what extent has — or should — the teaching of economics be modified … The simple answer is that the economics profession is unlikely to change. Why would economists be willing to give up much of their human capital, painstakingly nurtured for over two centuries? For macroeconomists in particular, the reaction has been to suggest that modifications of existing models to take account of ‘frictions’ or ‘imperfections’ will be enough to account for the current evolution of the world economy. The idea is that once students have understood the basics, they can be introduced to these modifications …

I would go further; rather than making steady progress towards

## A humble suggestion …

November 1, 2022A humble suggestion …

Read More »## Herman Daly (1938-2022)

October 31, 2022Ecological economist Herman Daly has passed away at the age of 84. Together with economists such as Kenneth Boulding and Nicholas Georgescu-Roegen, he was one of the founding fathers of ecological economics.

R.I.P.

## Alter Friedhof Prenzlauer Allee

October 29, 2022Alter Friedhof Prenzlauer Allee

Read More »