Zakaj v ekonomiji ni splošne resnice, ups, teorije

Dani Rodrik v kolumni in novi knjigi Economics Rules poudarja to, kar tudi sam ves čas poudarjam študentom: ker je ekonomija družbena znanost, ki ima opravka z bolj ali manj (ne)racionalnim obnašanjem ljudi ter neštetimi interakcijami med njimi, ne moremo imeti splošne ekonomske teorije, pač pa imamo lahko le partikularne teorije (modele) za posamezne situacije. Ne gre za to, da pridemo do konsenza, kateri model je najboljši, pač pa, kateri model (teorija) najboljše deluje v dani situaciji.

Kot sem že večkrat povedal: tako kot zdravniki vseh bolezni ne zdravijo z istimi zdravili, tudi v ekonomiji vseh vrst kriz ne bi smeli zdraviti z istimi ukrepi. Napaka je krizo, ki je posledica povpraševalnega šoka, zdraviti z ukrepi iz arzenala ekonomike ponudbe (nižanje davkov, strukturne reforme), in napaka je krizo, ki je posledica ponudbenega šoka, zdraviti z ukrepi iz arzenala keynesianske politike (dvig plač, večji javni izdatki za infrastrukturo). V prvem primeru se zaradi napačnega “zdravljenja” kriza le še poglablja, v drugem primeru pa dobite le inflacijo itd.

In to je, kot ugotavlja tudi Rodrik, za tiste, ki “delajo” ekonomsko politiko, bolj umetnost in obrt kot pa znanost.

Ever since the late nineteenth century, when economics, increasingly embracing mathematics and statistics, developed scientific pretensions, its practitioners have been accused of a variety of sins. The charges – including hubris, neglect of social goals beyond incomes, excessive attention to formal techniques, and failure to predict major economic developments such as financial crises – have usually come from outsiders, or from a heterodox fringe. But lately it seems that even the field’s leaders are unhappy.

Paul Krugman, a Nobel laureate who also writes a newspaper column, has made a habit of slamming the latest generation of models in macroeconomics for neglecting old-fashioned Keynesian truths. Paul Romer, one of the originators of new growth theory, has accused some leading names, including the Nobel laureate Robert Lucas, of what he calls “mathiness” – using math to obfuscate rather than clarify.

Richard Thaler, a distinguished behavioral economist at the University of Chicago, has taken the profession to task for ignoring real-world behavior in favor of models that assume people are rational optimizers. And finance professor Luigi Zingales, also at the University of Chicago, has charged that his fellow finance specialists have led society astray by overstating the benefits produced by the financial industry.

This kind of critical examination by the discipline’s big names is healthy and welcome – especially in a field that has often lacked much self-reflection. I, too, have taken aim at the discipline’s sacred cows – free markets and free trade – often enough.

But there is a disconcerting undertone to this new round of criticism that needs to be made explicit – and rejected. Economics is not the kind of science in which there could ever be one true model that works best in all contexts. The point is not “to reach a consensus about which model is right,” as Romer puts it, but to figure out which model applies best in a given setting. And doing that will always remain a craft, not a science, especially when the choice has to be made in real time.

The social world differs from the physical world because it is man-made and hence almost infinitely malleable. So, unlike the natural sciences, economics advances scientifically not by replacing old models with better ones, but by expanding its library of models, with each shedding light on a different social contingency.

Preberite več v Dani Rodrik, Project Syndicate

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