Central banks are back on the center stage of the global economic policy debate. The U.S. Federal Reserve and the European Central Bank now appear ready to ease monetary policy — in a turnaround from just some months ago when people were looking for "exit" and additional rate hikes.

In time-honored fashion, as soon as recession risks rise, pressure for monetary countermeasures goes up. The more ambitious political leaders are, the more intense the pressure gets. Unfortunately, there is growing evidence that monetary policy alone cannot do the trick of getting economies back on track. Money may make the world go round, but money alone does not create sustainable economic growth and prosperity.

No country serves as a better real-world example for the potential impotence of monetary action to create growth than Japan.