Uno dei vantaggi di avere a che fare con studenti è che si possono raccontare barzellette in classe approfittando della gentilezza e bontà loro, loro che sempre cercano di non mostrare facce disgustate e a volte anche accennano un sorriso.
La settimana scorsa, per rispondere a una domanda che riguardava l'efficienza dei mercati, ho riproposto quanto segue:
"Two economists are walking down the street and one of them notices what appears to be a $20 bill (or a $100 bill—the monetary amounts vary) on the sidewalk. “It’s not a real $20 bill,” the other economist declares. “If it were a real $20 bill, someone would have picked it up off the sidewalk already."
Di questa storiella esistono diverse varianti. Per esempio, io ho intrattenuto i miei studenti non raccontando della passeggiata di due colleghi economisti, ma di uno studente di dottorato con il suo relatore di tesi. Non per strada, ma per i giardini dell'università. E i dollari in questione non erano 20, ma 100. I miei studenti non hanno riso e neppure sorriso ma, come sempre, hanno mostrato molta educazione nei miei confronti.
Leggo ora, tra i "consigli di lettura" che Timothy Taylor scrive nel Journal of Economic Perspectives, di una intervista a Joseph Stiglits di Tyler Cowen (*)
"here’s Stiglitz on a 1980 paper written with Sandy Grossman: “The title of that paper was ‘On the Impossibility of Informationally Efficient Markets.’ It was an argument against the view that was held by people like Eugene Fama that markets were informationally efficient, that they transmitted efficiently all the information from the informed to the uninformed. We made the obvious observation that if that were the case, there would be no incentive for anybody to gather information. So the market
might be transmitting information, but it would be all free information. It would be information that nobody had done any work to collect. That idea, actually, in another context worries me very much today, that with Google and AI scraping so much information off of our newspapers, off of our podcasts, off of everything they can get a hold of, they’re trying to appropriate the value of the knowledge that’s
been created by other people without paying for it. If they succeed in doing that, of course, that will decrease the incentives for others to produce information of high quality and of value. It’s that kind of interaction that was at the heart of our 1980 paper, and the themes that we talked about there are still the critical themes that we’re talking about today.”
Che Twitter se ne vada non è poi male. Chissà che non sia una scusa per prendere più appunti altrove, per esempio qui.
(*) Journal of Economic Perspectives—Volume 38, Number 4—Fall 2024—Pages 229–236.