During the past three years, the Federal Reserve has tripled the size of its balance sheet—in effect printing $2 trillion—something it had never done in its nearly 100-year history. The Fed has lowered short-term interest rates to zero and signaled that it will keep them at that level for years. Inflation-adjusted short-term rates, or real rates, have been in the minus 2% range during the past couple of years for the first time since the 1970s.

The unfortunate fact is, as Milton Friedman famously observed, there is no free...