“Matematičnost” – maškerada akademske ideologije kot znanosti

Pred meseci sem pisal o tem, koliko ideologije lahko stlačimo v eno enačbo. Paul Romer iz NY University je pravkar objavil zelo pogumen članek z naslovom Mathiness (objavljen v prestižni AER Papers and Proceedings). V članku se je Romer lotil pristopa k znanosti veje ekonomske znanosti, ki ideologijo in politiko skriva v matematične enačbe. Ali drugače rečeno, lotil se je ekonomistov, ki svoja ideološka prepričanja zamaskirajo v enačbe in s tem implikacijam njihovih matematičnih modelov dajo pridih čiste znanstvene resnice. Ki pa so daleč od resnice, temveč so zgolj zamaskirana ideologija. In še več, so tudi iz matematičnega vidika napačne. Romer tej metodi pravi “mathiness” – “matematičnost” (za razliko od matematične teorije).

Romer kot začetnik teorije endogene rasti (endogeneous growth theory) je primer “matematičnosti” opisal na primeru modelov endogene rasti in ideološke bitke, ki se vodi na tem področju, ker en del ekonomistov, ki večinoma prihajajo iz univerze v Chicagu, zlorablja matematiko v ekonomski znanosti v ideološke namene. Gre za dolgo bitko, ki se je začela z Georgeom Stiglerjem, nobelovcem in karizmatičnim voditeljem ekonomske šole v Chicagu, ki ni priznavala nepopolne (monopolistične) konkurence, ampak zgolj popolno. Zato so v vse modele (predvsem pa v makroekonomske modele in modele gospodarske rasti) kot temelj njihove “mikrofundirane” optimalnosti sistematično vgradili popolno konkurenco, ki – po domače rečeno – priznava zgolj racionalnost agentov in posledično nezmotljivost trgov. Dopuščanje nepopolne konkurence bi pomenilo nepopolnost trgov in dalo prostor državi kot, v določenih primerih, bolj učinkovitemu akterju.

Romer se proti tej “matematičnosti” bori zaradi želje po večji znanstveni čistosti. Toda pri tem je nekoliko naiven v pričakovanju, da bo njegov apel vplival na ekonomsko strujo, ki jo poganja jasna ideološka podstat prostega trga. Ideologija je močnejša od znanstvene poštenosti in vedno bodo obstajali poskusi ideološke dogme stlačiti v matematične modele. Pri čemer nam je vsem jasno, da formalni modeli v ekonomiji niso reprezentativna slika realnosti, pač pa zgolj in samo reprezentacija osebnih prepričanj nekega raziskovalca. Če je nek pojav zapisan v matematične enačbe, še ne pomeni, da je s tem tudi pravilno opisan. Ali drugače rečeno, ko nek pojav opišemo z nekim zaporedjem črk iz abecede, to še nikakor ne pomeni, da smo ga tudi pravilno opisali. Sto ljudi bi ga opisalo na sto različnih načinov.

Nič drugače ni z uporabo matematike v ekonomiji. Le nekateri jo bolje obvladajo kot drugi in z njo lažje manipulirajo.

The point of the paper is that if we want economics to be a science, we have to recognize that it is not ok for macroeconomists to hole up in separate camps, one that supports its version of the geocentric model of the solar system and another that supports the heliocentric model. As scientists, we have to hold ourselves to a standard that requires us to reach a consensus about which model is right, and then to move on to other questions.

The alternative to science is academic politics, where persistent disagreement is encouraged as a way to create distinctive sub-group identities.

The usual way to protect a scientific discussion from the factionalism of academic politics is to exclude people who opt out of the norms of science. The challenge lies in knowing how to identify them.

From my paper:

The style that I am calling mathiness lets academic politics masquerade as science. Like mathematical theory, mathiness uses a mixture of words and symbols, but instead of making tight links, it leaves ample room for slippage between statements in natural versus formal language and between statements with theoretical as opposed to empirical content.

Persistent disagreement is a sign that some of the participants in a discussion are not committed to the norms of science. Mathiness is a symptom of this deeper problem, but one that is particularly damaging because it can generate a broad backlash against the genuine mathematical theory that it mimics. If the participants in a discussion are committed to science, mathematical theory can encourage a unique clarity and precision in both reasoning and communication. It would be a serious setback for our discipline if economists lose their commitment to careful mathematical reasoning.

The goal in starting this discussion is to ensure that economics is a science that makes progress toward truth. A necessary condition for making this kind of progress is a capacity for reaching consensus that is grounded in logic and evidence. Given how deeply entrenched positions seem to have become in macroeconomics, this discussion could be unpleasant. If animosity surfaces, it will be tempting to postpone this discussion. We should resist this temptation.

I know many of the people whose work I’m criticizing. I genuinely like them. It will be costly for many of us if disagreement spills over into animosity. But if it does, we can be confident that the bad feelings will pass and we should stay focused on the long run.

Vir: Paul Romer

In še primer “matematičnosti”, o katerih govori Romer – namerna uporaba matematično napačnih dokazov, tokrat s strani nobelovca Roberta Lucasa, da bi dokazal “veljavnost” svojega modela:

Romer1Romer2

Vir: Paul Romer

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