> "The idea that inflation and the money supply are linked is one of the most dumb one in folk economics"

"folk economics" implies it is by untrained people.

Milton Friedman's famous quote of "inflation is always and everywhere a monetary phenomenon" shows that he deeply believed the relationship between inflation and money supply, and one certainly cannot call Friedman a "folk economist" considering he won the Nobel prize in economics and was a professor at the University of Chicago.

Note: I am not saying he is right or supporting his belief. I am merely stating that such a belief is not a "folk economics" belief. This belief is still very prevalent in the freshwater schools of economics. [1]

As a personal anecdote, at Ronald Coase's 100th birthday party, I personally got Gary Becker and Richard Posner debating a very related topic (whether and by what degree the velocity of money of fluctuates and whether helicopter drops of cash would have been better during the early days of the money supply collapse in 2008/2009 than just giving money to the banks). In a room full of Nobel Prize winning economists in 2010, there was a very rigorous debate on the topic.

[1] https://en.wikipedia.org/wiki/Saltwater_and_freshwater_econo...

Lagged processes are one of the most fundamental concepts in economics. If merely recognizing the possibility that one could be at play here is throwing you for a loop, you need the simplified monetary model more than most.