Roger Farmer says the stock market crash caused the recession

The stock market crash of 2008 caused the Great Recession:Theory and evidence I think the cause and effect are weak since the stock market is an aggregator of events.

Here is the chart. Unemployment in blue, in the aggregate, was low in 2006. The market peaked, green,  in late 2007, and crashed in mid 2008. And unemployment jumped. So the claim is plausible.  The question become why the market crashed.  

The chart below gives a picture of the producer price index, and it peaked before the market crashed.  That was not a housing bubble, that was imported oil.