Od kar se je Kapital v 21. stoletju pojavil na knjižnih policah, so se nad njim in njegovim avtorjem, Thomasom Pikettyjem, začeli organizirati različni bolj ali manj prodorni kritični glasovi. Večina kritikov je streljala z razmeroma topimi puščicami in streljala iz deklarirano desnega političnega in strokovnega brega. Če gre verjeti The Economistu, je najbolj prodorna (in potencialno usodna) refutacija Kapitala uspela 26-letnemu doktorskemu študentu Massachusetts Institute of Technology (MIT), Matthewu Rognlieu.

THERE are lots of critics of “Capital in the Twenty-First Century”, Thomas Piketty’s study of increasing inequality in the rich world. Few have been as effective, however, as Matthew Rognlie, a 26-year-old graduate student at the Massachusetts Institute of Technology, who first took Mr Piketty to task in a 459-word blog post last year. On March 20th he presented a paper that expanded on the flaws he sees in Mr Piketty’s book.

Mr Piketty argues that over the long run the rate of return on wealth exceeds economic growth. Over time, this relationship increases inequality as the share of national income going to those who own capital (the rich) rises, while the portion going to labour (everyone else) falls. He also argues that the return on capital in recent history has been remarkably stable, even as economic growth has fallen, and that this trend will continue in the future.

Mr Rognlie has three main criticisms of all this. Several commentators have pointed out that the rate of return from capital should decline in the long run, rather than remaining high as Mr Piketty maintains, owing to the law of diminishing returns. Mr Rognlie expands on this, arguing that Mr Piketty has an inflated idea of the current return. Modern forms of capital, such as software, depreciate faster in value than equipment did in the past: a giant metal press might have a working life of decades whereas a new piece of database-management software will be obsolete in a few years at most. This means that returns from wealth may not necessarily be growing in net terms, since a rising share of the gains that flow to the owners of capital must be reinvested.

Vir: The Economist