For pension funds, insurance companies, and those with a healthy savings' account in Western Europe, historically low-interest rates are a problem. In some Eurozone member states, like Finland, the mortgage market is also beginning to show the traits of a bubble.

While the Federal Reserve is gradually returning to what a decade ago was considered “orthodox” and “normal,” Europe can’t follow. On the surface, the issue at hand is inflation. But, for the European Central Bank, the other big chal...