We are such an anxiety-ridden society that we worry about problems that haven't happened, and, almost certainly, won't. Robots are an apt example. Even McKinsey and Co., the high-powered management consulting firm, professes to be concerned. We imagine hordes of robots destroying jobs, leaving millions of middle-class families without work and income. Relax. Unless we adopt self-destructive policies, this is one doomsday we'll avoid.

One thing that the U.S. economy excels at is creating jobs. You might doubt this listening to Donald Trump and Hillary Clinton, who promise personally to create millions of high-paying jobs. This is misleading. The overwhelming share of jobs are created by the private market, not government or politicians.

Yes, there are recessions. Two of them in the post-World War II era were quite severe (those of 1981-1982 and 2007-2009). We had scary levels of unemployment. But eventually the job creation machine reasserts itself. In 2015, employment totaled 149 million, up from 99 million in 1980 and 137 million in 2000.