Is there any joint lesson to be learned from so-called Brexit and the unlikely-seeming elevation of Donald Trump to the position of President-elect of the United States? To certain sections of contemporary society in the Western world those two events were not just unexpected but unthinkable.

Was this because members of our somewhat complacent, left-leaning inner-city elites, say, not only do not know but probably cannot even imagine people who are entirely different from themselves and from their particular circles of friends and associates?

Half a century ago, the moral and social tone of most Western countries generally took some of its...