I've seen that Zeitgeist movie, its pretty good but the guy who made it is extremely biased. There is probably never 1 lone cause for a recession, but I would probably chalk a lot of it up to fear of debt and low confidence in the markets, which would be caused by the government being fiscally tight and raising taxes. In other words, some governments thought it to be advantageous to save money during a recession as a protective strategy. But when everybody is saving, money isn't being spent, people lose jobs and confidence, people save more, and here you have this vicious cycle.
Keynesian economics, which is cited in your link to the paper, represents the idea that the government must stimulate the economy in dire times, to encourage the flow of money and to support the country's weakening economy. A more modern example of this is the most recent recession caused by the housing bubble. The United States was in debt and funding multiple wars; they didn't have the cash reserves that they needed to stimulate the economy. Without the temporary support, the damages to the economy worsened and became harder to repair.