Perhaps Friedman's most widely known saying is that "inflation is a monetary phenomenon". In the last 30 years the correlation between money supply expansion a

Perhaps Friedman's most widely known saying is that "inflation is a monetary phenomenon". In the last 30 years the correlation between money supply expansion and inflation has been low. OTOH the correlation between supply shocks and inflation has been high. A real science would update in the face of contradictory evidence. Some economists have, but most haven't.