Eductive Stability in Real Business Cycle Models

We reexamine issues of coordination in the standard RBC model. Is the unique rational expectations equilibrium attainable by rational agents who contemplate the possibility of small deviations from equilibrium? Surprisingly, we find that coordination cannot be expected. Even with strong common knowledge assumptions, rational agents anticipating small but persistent deviations are led to take actions that eventually contradict the common knowledge assumption. This “impossibility†theorem for eductive learning is not fully overcome when adaptive learning is incorporated into the framework.