The German philosopher Jürgen Habermas, who died last month, was understandably despondent about much in the autumn of his career. Habermas’s reach across different disciplines was exceptional. A native of Düsseldorf, he was shaped by the legacy of the second World War, the western Germany that arose from its ashes, the cold war, the European integration project and the disintegration of the Soviet empire. His family conveniently adapted to the Nazi regime (he joined the Hitler Youth) without actively supporting it, but he later became the voice of the democratic left in Germany. His reputation was built on the concept...