Why epidemiological models only scratch the surface of the real world
29 Apr, 2020 at 14:52 | Posted in Politics & Society | 5 Comments
Yes indeed — the real world is way more complicated than mathematical models of it. And when it comes to choosing policies it is most often our estimations (guesses) of those very complications that decide what actions we take!
Simulating the effect of quarantine vs social distancing
29 Apr, 2020 at 12:36 | Posted in Varia | Comments Off on Simulating the effect of quarantine vs social distancing
Critical realism and Marxism
27 Apr, 2020 at 14:53 | Posted in Politics & Society | 3 CommentsAt the juncture of Roy Bhaskar’s refounding of critical realism philosophy of science, postmodernism had spread like a virus across academia with its seductive attack on grand theories or “metanarratives.” Neoliberal policies took advantage of the subsequently lowered intellectual immune systems and “identity politics” squabbling to impose its anti-working class “meta” economic model upon global humanity.
Where Bhaskar’s work struck with devastating consequences for degeneration of theories of knowledge toward irrealism was in his compelling argument over philosophy of science imbibing what he dubs the “epistemic fallacy.” Quite simply, what that entails is the belief that in answering the epistemological question of how we know something, the ontological question of what there is to be known is simultaneously answered. For Bhaskar, rather, it is the ontological question and the specific nature of the object of study in the real world which determines the form and scope of its possible science.
Further, Bhaskar argued that the “flat” ontological model of empiricism, which based scientific knowledge on observation, cannot explain how revolutions in science occur. Scientific change across the ages is possible because of an ontological structure of the world and all its furniture that is deep and stratified with causal mechanisms which generate myriad phenomenon we observe. Capturing these causal mechanisms and the scientific laws they designate operates through a process of “retroduction.” Here, scientists puzzled by phenomena both in terms of observation and limits of current theory posit the existence of a deep causal mechanism responsible for those surface manifestations they perceived. Scientific truth is reached when a correspondence is arrived at between the causal structure of the object of knowledge to be explained or defined and the logical structure of the theory that purports to explain or define it.
Armed with Bhaskar’s bringing ontology back in to science it is possible to rethink Marx’s claims for his economic theory in Capital as the founding work of a new science. After all, almost a century following the passing of Marx, work of economic historians such as Karl Polanyi and Robert Heilbroner is referred to for their grasp respectively of marketization “disembedding” economic life from other social practices or markets “creating” an “economic society” from the social fabric. Yet, what precisely causes economic life in the capitalist era to appear to levitate from the social or create a “separate sphere” of society is never explained.
Hur får vi en mer likvärdig skola?
27 Apr, 2020 at 08:06 | Posted in Education & School | 1 CommentUtredningen om en mer likvärdig skola lämnar i dag förslag om ett förändrat skolval och en förändrad resurstilldelning till skolan för att alla elever ska få samma chans. Den övergripande slutsatsen är att staten behöver ta ett större ansvar för att skolan ska bli mer likvärdig …
En viktig förklaring till den ökade skolsegregationen är den allt större boendesegregationen men skolvalet och den ökade andelen elever i fristående skolor har bidragit till utvecklingen. Sett ur skolans hela uppdrag är allsidigt sammansatta skolor och klasser väsentligt. Skolans funktion kan beskrivas i termer av kvalifikation för arbetsliv och för ett aktivt samhällsliv, socialisering och personlig utveckling. Allsidigt sammansatta skolor och klasser ger goda möjligheter för alla elevers utveckling i samtliga avseenden och stärker skolans demokratiska roll som mötesplats. Det är centralt att alla elever går i skolor som håller hög kvalitet.
Internationellt sett är den svenska grundskolan som helhet relativt likvärdig och skolsegregationen begränsad. Detta beror dock i hög grad på att svensk grundskola är sammanhållen relativt högt upp i åldrarna. Svensk skola är däremot internationellt sett endast medelmåttig vad gäller att klara det så kallade kompensatoriska uppdraget och uppväga elevernas socioekonomiska förutsättningar och vad värre är, utvecklingen går åt fel håll. Skolsegregationen ökar, vi ser tecken på minskad likvärdighet och att skolan klarar det kompensatoriska uppdraget allt sämre. Detta är allvarligt och en utveckling som måste brytas.
Utredningens analyser av skolors resurser per elev visar på mycket stora skillnader mellan olika delar av landet. Skolor i en del av landet har dubbelt så stora resurser tillgängliga per elev som skolor i en annan. Det kan finnas helt rimliga förklaringar till varför skillnaderna är stora, till exempel påverkar glesbygdsgrad, lokalt löneläge och elevernas förutsättningar kostnaderna. Utredningen finner dock att endast ungefär hälften av variationen mellan kommuner förklaras av de faktorer som utredningen prövat. Det faktum att till exempel kommunens finansieringsförmåga får genomslag i sambandsanalyserna utgör ett tydligt problem i ett likvärdighetshänseende.
I Sverige år 2020 låter vi friskolekoncerner med undermålig verksamhet få plocka ut skyhöga vinster — vinster som den svenska staten gladeligen låter dessa koncerner ta av vår skattefinansierade skolpeng. Dessa smarta välfärdsplundrare har överlag en högre lönsamhet än näringslivet i sin helhet, men när man väl plundrat färdigt lämnar man över problemen och eleverna till den förkättrade offentliga sektorn.
Många är med rätta upprörda och de som är kritiska till privatisering av vård och skola har haft gyllene tillfällen att tydligt och klart tala om att man nu vill se till att undanröja möjligheterna för vinstdrivande bolag att verka inom vård, omsorg och skola.
Men så har inte skett. Istället har det kommit en jämn ström av krav på ökad kontroll, tuffare granskning och inspektioner. När nu privatiseringsvåtdrömmen visar sig vara en mardröm så tror man att just det som man ville bli av med — regelverk och ‘byråkratisk’ tillsyn och kontroll — skulle vara lösningen.
Ett flertal undersökningar har på senare år visat att det system vi har i Sverige med vinstdrivande skolor leder till att våra skolor blir allt mindre likvärdiga — och att detta i sin tur bidrar till allt sämre resultat. Ska vi råda bot på detta måste vi ha ett skolsystem som inte bygger på ett marknadsmässigt konkurrenstänk där skolor istället för att utbilda främst ägnar sig åt att ragga elever och skolpeng, utan drivs som icke-vinstdrivna verksamheter med kvalitet och ett klart och tydligt samhällsuppdrag och elevernas bästa för ögonen.
Sverige har varit internationellt unikt genom att tillåta vinstuttag i friskolor. En lagändring skulle här innebära att Sverige i likhet med andra länder omöjliggör vinstutdelning på friskolor finansierade med offentliga medel. Detta skulle också innebära att vi får en lagstiftning som går hand i hand med vad svenska folket tycker, eftersom opinionsundersökningar gång visat att en klar majoritet anser att friskolor ska vara skyldiga att återinvestera hela överskottet i skolan.
Man ska komma ihåg att det striden gäller egentligen inte är om verksamheter får gå med vinst eller inte, eftersom en vinst — ett överskott — som återinvesteras i verksamheten är en förutsättning för att skolor ska kunna överleva och utvecklas på sikt. Vad striden gäller är vinstdelning — om vinsten ska få lov att lämna verksamheten i form av t. ex. aktieutdelning. Detta avspeglas också i val av bolagsform och vilka aktörer skolföreträdare värnar. De som prioriterar lönsamhet och finansiärer, väljer ofta att driva verksamheten i bolagsform eftersom det underlättar för externa finansiärer att få avkastning på satsat kapital. De flesta av dagens friskolor drivs i bolagsform och de största skolkoncernerna ägs numera av riskkapitalbolag vars huvudsakliga syfte är att förvärva företag för att så snart som möjligt avyttra dem med vinst.
Vi vet idag att friskolor driver på olika former av etnisk och social segregation, påfallande ofta har låg lärartäthet och dåliga skolresultat, och i grund och botten sviker resurssvaga elever. Att dessa verksamheter ska premieras med att få plocka ut vinster på våra skattepengar är djupt stötande. I ett samhälle präglat av jämlikhet, solidaritet och demokrati borde det vara självklart att skattefinansierade skolor inte ska få drivas med vinst och vinstutdelning som främsta ledstjärnor
De politisk partierna måste droppa sina ideologiska skygglappar och inse att en och annan helig ko måste slaktas om vi ska få rätt på svensk skola. När skolfakta sparkar så får man vara så god att ändra kurs – även om det eventuellt skulle stå i strid med ideologin. När ska de politiska partierna gemensamt våga ta det steget? Ska vi verkligen behöva vänta tills nästa PISA undersökning åter igen pekar på svensk skolas katastrofala utförsåkning?
Jag har sagt det förr — och jag säger det igen: kommunaliseringen av skolan är den största floppen någonsin i svensk utbildningspolitisk historia. Men misstag går att rätta till. Som den store engelske nationalekonomen John Maynard Keynes brukade säga: “When I’m wrong, I change my mind.”
Staten bör åter — om vi ska ha en rimlig chans nå målet om en likvärdig skola — få det övergripande ansvaret för vårt skolsystem.
‘One day we shall die. But all the other days we shall be alive.’
26 Apr, 2020 at 19:49 | Posted in Varia | Comments Off on ‘One day we shall die. But all the other days we shall be alive.’
Per Olov Enquist, one of Sweden’s most acclaimed authors and intellectuals has died. RIP.
The relationship between logic and truth
26 Apr, 2020 at 14:20 | Posted in Theory of Science & Methodology | 13 Comments
To be ‘analytical’ and ‘logical’ is something most people find recommendable. These words have a positive connotation. Scientists think deeper than most other people because they use ‘logical’ and ‘analytical’ methods. In dictionaries, logic is often defined as “reasoning conducted or assessed according to strict principles of validity” and ‘analysis’ as having to do with “breaking something down.”
But that’s not the whole picture. As used in science, analysis usually means something more specific. It means to separate a problem into its constituent elements so to reduce complex — and often complicated — wholes into smaller (simpler) and more manageable parts. You take the whole and break it down (decompose) into its separate parts. Looking at the parts separately one at a time you are supposed to gain a better understanding of how these parts operate and work. Built on that more or less ‘atomistic’ knowledge you are then supposed to be able to predict and explain the behaviour of the complex and complicated whole.
In economics, that means you take the economic system and divide it into its separate parts, analyse these parts one at a time, and then after analysing the parts separately, you put the pieces together.
The ‘analytical’ approach is typically used in economic modelling, where you start with a simple model with few isolated and idealized variables. By ‘successive approximations,’ you then add more and more variables and finally get a ‘true’ model of the whole.
This may sound like a convincing and good scientific approach.
But there is a snag!
The procedure only really works when you have a machine-like whole/system/economy where the parts appear in fixed and stable configurations. And if there is anything we know about reality, it is that it is not a machine! The world we live in is not a ‘closed’ system. On the contrary. It is an essentially ‘open’ system. Things are uncertain, relational, interdependent, complex, and ever-changing.
Without assuming that the underlying structure of the economy that you try to analyze remains stable/invariant/constant, there is no chance the equations of the model remain constant. That’s the very rationale why economists use (often only implicitly) the assumption of ceteris paribus. But — nota bene — this can only be a hypothesis. You have to argue the case. If you cannot supply any sustainable justifications or warrants for the adequacy of making that assumption, then the whole analytical economic project becomes pointless non-informative nonsense. Not only have we to assume that we can shield off variables from each other analytically (external closure). We also have to assume that each and every variable themselves are amenable to be understood as stable and regularity producing machines (internal closure). Which, of course, we know is as a rule not possible. Some things, relations, and structures are not analytically graspable. Trying to analyse parenthood, marriage, employment, etc, piece by piece doesn’t make sense. To be a chieftain, a capital-owner, or a slave is not an individual property of an individual. It can come about only when individuals are integral parts of certain social structures and positions. Social relations and contexts cannot be reduced to individual phenomena. A cheque presupposes a banking system and being a tribe-member presupposes a tribe. Not taking account of this in their ‘analytical’ approach, economic ‘analysis’ becomes uninformative nonsense.
Using ‘logical’ and ‘analytical’ methods in social sciences means that economists succumb to the fallacy of composition — the belief that the whole is nothing but the sum of its parts. In society and in the economy this is arguably not the case. An adequate analysis of society and economy a fortiori cannot proceed by just adding up the acts and decisions of individuals. The whole is more than a sum of parts.
Mainstream economics is built on using the ‘analytical’ method. The models built with this method presuppose that social reality is ‘closed.’ Since social reality is known to be fundamentally ‘open,’ it is difficult to see how models of that kind can explain anything about what happens in such a universe. Postulating closed conditions to make models operational and then impute these closed conditions to society’s real structure is an unwarranted procedure that does not take necessary ontological considerations seriously.
In face of the kind of methodological individualism and rational choice theory that dominate mainstream economics we have to admit that even if knowing the aspirations and intentions of individuals are necessary prerequisites for giving explanations of social events, they are far from sufficient. Even the most elementary ‘rational’ actions in society presuppose the existence of social forms that it is not possible to reduce to the intentions of individuals. Here, the ‘analytical’ method fails again.
The overarching flaw with the ‘analytical’ economic approach using methodological individualism and rational choice theory is basically that they reduce social explanations to purportedly individual characteristics. But many of the characteristics and actions of the individual originate in and are made possible only through society and its relations. Society is not a Wittgensteinian ‘Tractatus-world’ characterized by atomistic states of affairs. Society is not reducible to individuals, since the social characteristics, forces, and actions of the individual are determined by pre-existing social structures and positions. Even though society is not a volitional individual, and the individual is not an entity given outside of society, the individual (actor) and the society (structure) have to be kept analytically distinct. They are tied together through the individual’s reproduction and transformation of already given social structures.
Since at least the marginal revolution in economics in the 1870s it has been an essential feature of economics to ‘analytically’ treat individuals as essentially independent and separate entities of action and decision. But, really, in such a complex, organic and evolutionary system as an economy, that kind of independence is a deeply unrealistic assumption to make. To simply assume that there is strict independence between the variables we try to analyze doesn’t help us the least if that hypothesis turns out to be unwarranted.
To be able to apply the ‘analytical’ approach, economists have to basically assume that the universe consists of ‘atoms’ that exercise their own separate and invariable effects in such a way that the whole consist of nothing but an addition of these separate atoms and their changes. These simplistic assumptions of isolation, atomicity, and additivity are, however, at odds with reality. In real-world settings, we know that the ever-changing contexts make it futile to search for knowledge by making such reductionist assumptions. Real-world individuals are not reducible to contentless atoms and so not susceptible to atomistic analysis. The world is not reducible to a set of atomistic ‘individuals’ and ‘states.’ How variable X works and influence real-world economies in situation A cannot simply be assumed to be understood or explained by looking at how X works in situation B. Knowledge of X probably does not tell us much if we do not take into consideration how it depends on Y and Z. It can never be legitimate just to assume that the world is ‘atomistic.’ Assuming real-world additivity cannot be the right thing to do if the things we have around us rather than being ‘atoms’ are ‘organic’ entities.
If we want to develop new and better economics we have to give up on the single-minded insistence on using a deductivist straitjacket methodology and the ‘analytical’ method. To focus scientific endeavours on proving things in models is a gross misapprehension of the purpose of economic theory. Deductivist models and ‘analytical’ methods disconnected from reality are not relevant to predict, explain or understand real-world economies
To have ‘consistent’ models and ‘valid’ evidence is not enough. What economics needs are real-world relevant models and sound evidence. Aiming only for ‘consistency’ and ‘validity’ is setting the economics aspirations level too low for developing a realist and relevant science.
Economics is not mathematics or logic. It’s about society. The real world.
Models may help us think through problems. But we should never forget that the formalism we use in our models is not self-evidently transportable to a largely unknown and uncertain reality. The tragedy with mainstream economic theory is that it thinks that the logic and mathematics used are sufficient for dealing with our real-world problems. They are not! Model deductions based on questionable assumptions can never be anything but pure exercises in hypothetical reasoning.
The world in which we live is inherently uncertain and quantifiable probabilities are the exception rather than the rule. To every statement about it is attached a ‘weight of argument’ that makes it impossible to reduce our beliefs and expectations to a one-dimensional stochastic probability distribution. If “God does not play dice” as Einstein maintained, I would add “nor do people.” The world as we know it has limited scope for certainty and perfect knowledge. Its intrinsic and almost unlimited complexity and the interrelatedness of its organic parts prevent the possibility of treating it as constituted by ‘legal atoms’ with discretely distinct, separable and stable causal relations. Our knowledge accordingly has to be of a rather fallible kind.
If the real world is fuzzy, vague and indeterminate, then why should our models build upon a desire to describe it as precise and predictable? Even if there always has to be a trade-off between theory-internal validity and external validity, we have to ask ourselves if our models are relevant.
‘Human logic’ has to supplant the classical — formal — logic of deductivism if we want to have anything of interest to say of the real world we inhabit. Logic is a marvellous tool in mathematics and axiomatic-deductivist systems, but a poor guide for action in real-world systems, in which concepts and entities are without clear boundaries and continually interact and overlap. In this world, I would say we are better served with a methodology that takes into account that the more we know, the more we know we do not know.
Mathematics and logic cannot establish the truth value of facts. Never has. Never will.
Johan Giesecke on why lockdowns are the wrong policy
26 Apr, 2020 at 13:03 | Posted in Politics & Society | 16 Comments
Wissenschaftskommunikation in Zeiten der Coronavirus
26 Apr, 2020 at 10:56 | Posted in Politics & Society | 3 Comments
Wann ist die Pandemie vorbei?
26 Apr, 2020 at 09:56 | Posted in Varia | Comments Off on Wann ist die Pandemie vorbei?
Schweden fährt in der Corona-Krise seinen eigenen Kurs
26 Apr, 2020 at 09:23 | Posted in Varia | Comments Off on Schweden fährt in der Corona-Krise seinen eigenen Kurs
Pandemic depression antidote (VII)
25 Apr, 2020 at 17:16 | Posted in Varia | Comments Off on Pandemic depression antidote (VII)
War veteran Tom Moore has won the hearts of people by raising more than £30 million for the NHS by walking laps of his garden. Thanks, Captain Tom!
Haavelmo and modern probabilistic econometrics — a critical-realist perspective (wonkish)
24 Apr, 2020 at 11:52 | Posted in Statistics & Econometrics | 2 CommentsMainstream economists often hold the view that criticisms of econometrics are the conclusions of sadly misinformed and misguided people who dislike and do not understand much of it. This is a gross misapprehension. To be careful and cautious is not equivalent to dislike.
The ordinary deductivist ‘textbook approach’ to econometrics views the modelling process as foremost an estimation problem since one (at least implicitly) assumes that the model provided by economic theory is a well-specified and ‘true’ model. The more empiricist, general-to-specific-methodology (often identified as the ‘LSE approach’) on the other hand views models as theoretically and empirically adequate representations (approximations) of a data generating process (DGP). Diagnostics tests (mostly some variant of the F-test) are used to ensure that the models are ‘true’ – or at least ‘congruent’ – representations of the DGP. The modelling process is here more seen as a specification problem where poor diagnostics results may indicate a possible misspecification requiring re-specification of the model. The objective is standardly to identify models that are structurally stable and valid across a large time-space horizon. The DGP is not seen as something we already know, but rather something we discover in the process of modelling it. Considerable effort is put into testing to what extent the models are structurally stable and generalizable over space and time.
Although I have sympathy for this approach in general, there are still some unsolved ‘problematics’ with its epistemological and ontological presuppositions. There is, e. g., an implicit assumption that the DGP fundamentally has an invariant property and that models that are structurally unstable just have not been able to get hold of that invariance. But, as already Keynes maintained, one cannot just presuppose or take for granted that kind of invariance. It has to be argued and justified. Grounds have to be given for viewing reality as satisfying conditions of model-closure. It is as if the lack of closure that shows up in the form of structurally unstable models somehow could be solved by searching for more autonomous and invariable ‘atomic uniformity.’ But if reality is ‘congruent’ to this analytical prerequisite has to be argued for, and not simply taken for granted.
A great many models are compatible with what we know in economics — that is to say, do not violate any matters on which economists are agreed. Attractive as this view is, it fails to draw a necessary distinction between what is assumed and what is merely proposed as hypothesis. This distinction is forced upon us by an obvious but neglected fact of statistical theory: the matters ‘assumed’ are put wholly beyond test, and the entire edifice of conclusions (e.g., about identifiability, optimum properties of the estimates, their sampling distributions, etc.) depends absolutely on the validity of these assumptions. The great merit of modern statistical inference is that it makes exact and efficient use of what we know about reality to forge new tools of discovery, but it teaches us painfully little about the efficacy of these tools when their basis of assumptions is not satisfied.
Even granted that closures come in degrees, we should not compromise on ontology. Some methods simply introduce improper closures, closures that make the disjuncture between models and real-world target systems inappropriately large. ‘Garbage in, garbage out.’
Underlying the search for these immutable ‘fundamentals’ lays the implicit view of the world as consisting of entities with their own separate and invariable effects. These entities are thought of as being able to be treated as separate and addible causes, thereby making it possible to infer complex interaction from a knowledge of individual constituents with limited independent variety. But, again, if this is a justified analytical procedure cannot be answered without confronting it with the nature of the objects the models are supposed to describe, explain or predict. Keynes himself thought it generally inappropriate to apply the ‘atomic hypothesis’ to such an open and ‘organic entity’ as the real world. As far as I can see these are still appropriate strictures all econometric approaches have to face. Grounds for believing otherwise have to be provided by the econometricians.
Lucas’ Copernican revolution
23 Apr, 2020 at 08:50 | Posted in Economics | 1 CommentIn Michel De Vroey’s version of the history of macroeconomics, Robert Lucas’ declaration of the need for macroeconomics to be pursued only within ‘equilibrium discipline’ and declaring equilibrium to exist as a postulate, is hailed as a ‘Copernican revolution.’ Equilibrium is not to be considered something that characterises real economies, but rather “a property of the way we look at things.” De Vroey, approvingly, notices that this — as well as Lucas’ banning of disequilibrium as referring to ‘unintelligible behaviour’ — “amounts to shrinking the pretence of equilibrium theory.”
Mirabile dictu!
Is it really a feasible methodology for economists to make a sharp divide between theory and reality, and then — like De Vroey and Lucas — treat the divide as something recommendable and good? I think not.
Fortunately, there are other economists with a less devoted hagiographic attitude towards Lucas and his nonsense on stilts.
Alessandro Vercelli is one:
The equilibria analysed by Lucas are conceived as stationary stochastic processes. The fact that they are stationary imposes a long series of restrictive hypotheses on the range of applicability of the heuristic model, and these considerably reduce the empirical usefulness of Lucas’s equlibrium method …
For such a method to make sense … the stationary ‘equilibrium’ stochastic process must also be ‘dynamically stable,’ or ‘ergodic,’ in the terminology of stochastic processes …
What is worse, if one adopts Lucas’s method of pure equilibrium implying the non-intelligibility of disequilibrium positions, there is no way to argue about the robustness of the alternative equilibria under consideration. In other words, Lucas’s heuristic model, not to mention the analytical models built according to his instructions, prove to be useless for the very purpose for which they were primarily constructed — the evaluation of alternative economic policies.
Another one is Roman Frydman, Professor of Economics at New York University and a long time critic of the rational expectations hypothesis. In his seminal 1982 American Economic Review article Towards an Understanding of Market Processes — an absolute must-read for anyone with a serious interest in understanding what are the issues in the present discussion on rational expectations as a modelling assumption — he showed that the kind of models that Lucas recommends — models founded on ‘equilibrium discipline’ and the rational expectations hypothesis — is inadequate as a representation of economic agents’ decision making.
Those who want to build macroeconomics on microfoundations usually maintain that the only robust policies and institutions are those based on rational expectations and representative actors. As yours truly has tried to show in On the use and misuse of theories and models in economics there is really no support for this conviction at all. For if this microfounded macroeconomics has nothing to say about the real world and the economic problems out there, why should we care about it? The final court of appeal for macroeconomic models is the real world, and as long as no convincing justification is put forward for how the inferential bridging de facto is made, macroeconomic modelbuilding is little more than hand waving that give us rather a little warrant for making inductive inferences from models to real-world target systems. If substantive questions about the real world are being posed, it is the formalistic-mathematical representations utilized to analyze them that have to match reality, not the other way around.
The real macroeconomic challenge is to accept uncertainty and still try to explain why economic transactions take place – instead of simply conjuring the problem away à la Lucas by assuming equilibrium and rational expectations, and treating uncertainty as if it was possible to reduce to stochastic risk. That is scientific cheating. And it has been going on for too long now.
Tom Britton on the mathematics of the corona outbreak
21 Apr, 2020 at 19:53 | Posted in Politics & Society | 4 Comments
Blog at WordPress.com.
Entries and Comments feeds.