There is no doubt that Karl Jaspers was one of the greatest philosophers of the twentieth century. This statement seems uncontroversial, at least among all those not beholden to the belief that the analytical tradition is the only valid embodiment of professional philosophy. During that period of postwar history when “existential philosophy” dominated intellectual and cultural life in Europe and beyond, Jaspers's name cropped up constantly, together with those of Martin Heidegger and Jean-Paul Sartre, as the most important and certainly most prominent contemporary thinkers. At the time, his influence on the general reading public and on up-and-coming figures was enormous. Two members of this younger cohort stand out, namely Paul Ricoeur and Jürgen Habermas. The first two books published by Ricoeur—soon after his liberation from a German prisoner-of-war camp, where he had spent several years—were on Jaspers; the complex balancing act between philosophical thinking and religious faith that we find in Jaspers became crucial to Ricoeur's entire intellectual development and to the way he articulated his opposition to the atheist “existentialism” of Sartre. Again and again, Ricoeur stated that, like Jaspers, for him philosophy and faith have to be seen as engaged in a “loving struggle.” Although he disagreed with Jaspers in crucial respects and was clearly more of a Christian than Jaspers himself, he emulated the latter's characteristic efforts to mediate between seemingly contradictory positions. “Cette via media, c’est Jaspers,” he wrote in the last paragraph of his first book.

The other budding talent, Jürgen Habermas, completed his doctoral dissertation on Schelling in 1954, and when Jaspers's monograph on the same thinker appeared in 1955, he reviewed it in Germany's leading daily. Further newspaper articles on Jaspers followed, and in his late masterpiece, which foregrounds the relationship between philosophy and religion in European intellectual history, Habermas found himself returning to Jaspers's work. Beyond this, it is plainly apparent that Habermas's fascination with the phenomena of “communicative action” owes much to Jaspers's illuminating analyses.