Economies fluctuate in complex ways, but tend to grow. This paper shows how growth and fluctuations emerge in a post-Keynesian model.

The model presented in the paper features an equilibrium in which diverse possible economic growth rates coincide. However, the model is typically out of equilibrium. Dynamic processes unfolding over both short and long time scales lead the economy to exhibit both business cycles and long waves. The model features short‐run instability, which is bounded from above by installed productive capacity. Labor constraints enter indirectly, creating conflict over wage-setting. The paper is a contribution to a long-term program to build long-run economic models for sustainability studies.