Learned optimism in macroeconomics

I just couldn't resist coming up with that quip after reading Krugman's Learned Helplessness post.

I assume that the lessons that we are to take away from his post is that since the Great Depression was made more severe by austerity measures and tightening by the Fed (by raising interest rates and reserve requirements) we should not only avoid to repeat these mistakes but also by doing the exact opposite. While the debate on effectiveness of monetary policy vis a vis fiscal policy at the zero bound continues to rage (?), I only came up with the quip because for some the debate is settled and there is nothing more to discuss. Onward we go!