Say's law, an idea in classical economics, rejects the possibility of general overproduction. It states that supply creates its own demand. The classical economists believed that savings are always invested, so aggregate supply equals aggregate demand, ensuring full employment. However, they acknowledged that monetary disturbances could cause temporary disequilibria by affecting money demand. Adjustment mechanisms, like interest rate changes, would bring the economy back to equilibrium at full employment over time. So Say's law expressed an equilibrium condition, not something always true.