La lettura dei gionali, e, quando on-line, anche dei commenti dei lettori è istruttiva. Molti pensano che gli economisti abbiano prodotto una scienza arida, oppure che siano degli incapaci, non avendo previsto la crisi. Di seguito una guida ai link che mostrano che le cose non sono proprio così, oppure, se anche sono così, sono più complesse.
Critica. L'economia è una disciplina arida, perchè assume che tutti siano delle macchine da calcolo. Ossia che gli umani pensino solo a render massima la propria utilità. Non è vero, ci sono le passioni, i sentimenti, ecc. Difesa. Assumere che tutti siano calcolanti è una buona approssimazione. Infatti, se nessuno fosse calcolante, la domanda dei beni salirebbe con i prezzi dei medesimi che salgono, il che non è. I prezzi delle attività finanziarie con fatica e alla lunga tornano sui propri valori, insomma non vagano nell'assoluto nulla. L'altruismo è studiato; l'avversione al rischio con le sue implicazioni; la dinamica dei matrimoni; la storia.
Critica. Gli economisti non hanno predetto la crisi. Ecco la prova che non sanno fare il proprio lavoro. Difesa. Perchè non l'hanno predetta? Riproduco questo post che propone un'ipotesi:
It was/is a banking crisis, not a financial crisis - and, I'd add, a failure of ownership structures rather than of markets. If high debt were the main culprit, you'd expect defaults and bad debts to have risen before the recession. They did, but not by much. In late 2007, the delinquency rate on US household mortgages was less than a percentage point above its mid-90s level. The biggest rise came after Lehmans collapsed. Nor is it obvious that the bursting of the housing bubble was to blame. US prices fell 10% between April 2006 and late 2007 whilst the economy continued to grow. Instead, the problem was that the losses caused by the bursting of the US housing bubble were concentrated among a few organization who - we now know - were unable to bear them. Had the losses been more dispersed - as the tech burst's losses in 2000-03 were - the macro effects would have been much less nasty. It's not just in the US where organizational failure has serious macro effects. The euro crisis can be seen as a crisis of risk-bearing - too much is concentrated in a few organizations - rather than as a debt crisis. There are two aspects of the problem here. The obvious one is that some large firms/banks are strategically significant. Also, banks are prone to a common systems (pdf) failure. This might be due to interlinkages between them - so that a "fire sale" of assets by one bank depresses prices and so worsens others' solvency. Or it might be because if all banks follow the same strategy then anything that wipes out one will wipe out all. Just as a common environmental change - such as the disappearance of a food source - can wipe out an entire species, so it can wipe out an entire set of firms. And here, conventional macro is at fault. It has generally presumed that the economy is smooth rather than granular, and thus that specific corporate failures can be ignored. They can't be. This failure has been compounded by the tendencies: to regard macro shocks as Gaussian;to ignore discontinuity and complexity in favour of more easily tractable models; and by the presumption that firms/banks are rationally managed. I have this suspicion that the nature of macroeconomics - with its emphasis upon mathematical tractability rather than complexity - is influenced more by what can be safely inflicted upon students than by what best describes the real world.
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