… is from page 342 of the 2016 second edition of Thomas Sowell’s excellent volume Wealth, Poverty and Politics  (footnote deleted; link added):
To say that pay differences between people at the top and people at the bottom have increased over the years means something very different when these are differences between classes than when these are differences between people in different age brackets. When some people are in the bottom quintile for life and others are in the top quintile for life, that is a very different situation from one in which most people move from one quintile to another within a decade. Only 11 percent of Americans 25 years old have been in a household within the top 20 percent of household incomes. But 70 percent of Americans 60 years old have been in such a household at some point in their lives . Since every 60-year-old was once a 25-year-old, increased income differences between age brackets are hardly an injustice to Americans who live a normal life span.
DBx: How many Progressives who preen about their insistence on “following the science” also ignore, when they complain about income ‘inequality,’ this scientific fact? (Methinks many.)