I can’t believe how much excellent material Scott Sumner hides “below the fold.”  A prime example

Whenever I read opinion pieces by almost any macroeconomist–
Keynesian, monetarist, new Classical, Austrian, etc, there is almost
invariably a point where alarm bells go off.  At some point the
economist will make an assertion that seems to me to be in conflict
with the EMH.  And after that point I have trouble taking anything they
say seriously.  I keep thinking “If you’re so smart . . . “

If you read through all my posts you will have trouble finding a
single assertion that is at variance with the EMH.  In contrast, pick
up almost any other economist’s take on the current crisis and you will
almost invariable find at least one assertion that conflicts with the
EMH.  It’s always something like “the root cause of the crisis occurred
years earlier when . . .”

1.  The Fed set interest rates too low

2.  Regulators let banks make excessively risky loans (or if you’re a right winger-encouraged them to make risky loans.)

3.  Americans didn’t save enough

And so on.  In contrast, I believe that the depression was caused by events that took place in September and October, when the markets actually crashed.
Which depression?  All of them–1929, 1937, 2008, etc.  And as far as I
know I am the only economist who believes that all of these depressions
were caused by events that occurred in those two fateful months.

This argument is so persuasive that I’m strongly tempted to second Scott.  My main proviso: He’s got to let me count the public’s panic as an “event that occured in those two fateful months.”  How about it, Scott?