… is from pages 125-126 of University of Notre Dame philosopher James Otteson’s superb and hot-off-the-Cambridge-University-Press book, Seven Deadly Economic Sins (2021)  (three links added; footnote deleted):
What has changed over humanity’s recent history is not biology, psychology, physiology, ecology, or geography. What has changed, instead, is their attitudes. As economic historian Deirdre McCloskey has demonstrated in her magisterial three-volume investigation under the general title The  Bourgeois  Era , the most salient factor distinguishing the post-1800 era from everything that went before is the attitudes people held toward others. Before that period, the standard background assumption people had was that some people are superior to others – more specifically, one’s own people are superior to those other people – and hence people believed they were under no obligation, moral or otherwise, to treat all human beings as their moral equals. What began as an inkling in the sixteenth century, gained some traction in the seventeenth century, and then began to spread in the eighteenth century, was the idea that cooperation was not only allowable, but morally appropriate; and not only with some people, but with ever more people. As that idea spread, more and more cooperative behavior was engaged in, leading to mutually beneficial exchanges and partnerships, which launched world prosperity on the precipitate upward slope we have seen since.