Stabilizing and destabilizing mechanisms: A new perspective to understand business cycles

Economists believe that economic fluctuations can be smoothed by stabilization mechanisms, such as price adjustment, embedded in the economy. While price adjustment can be seen as a stabilization mechanism, are there mechanisms that can destabilize an economy? We find that as early as 1939, Harrod discussed a destabilization mechanism, the firm's investment adjustment, illustrated in his knife-edge puzzle. We build a macro-dynamic model with investment and price as the core macroeconomic variables. Our analysis shows that the interaction between the stabilization mechanism (price adjustment) and the destabilization mechanism (investment adjustment) generates fluctuations and cycles. However, due to price stickiness, the price adjustment mechanism may not be enough to stabilize the economy. In this case, a government stabilization policy is necessary for further stabilization. As this paper also addresses the microfoundations of Keynesian quantity theory, including the choice of output and investment in optimization, it can be related to traditional Keynesian economics, with a new perspective to understand business cycles.