The article explains why policies for dealing with recessions and depressions are different. It uses a model that focuses on how profit growth, interest rates, and prices affect economic growth. The model shows that in a recession, adjusting savings can help the economy recover, but in a depression, this approach doesn't work. Instead, direct state investment is needed to create demand and reduce unemployment to get the economy moving again. This means that policies for recessions and depressions need to be different, with a focus on creating demand and reducing unemployment in depressions.