" In Germany, Martin Heidegger turned against his former mentor Edmund Husserl, but later Heidegger's friends and colleagues turned their backs on him. In France, Gabriel Marcel attacked Jean-Paul Sartre, Sartre fell out with Camus, Camus fell out with Merleau-Ponty, Merleau-Ponty fell out with Sartre, and the Hungarian intellectual Arthur Koestler fell out with everyone and punched Camus in the street. "

― Sarah Bakewell , At the Existentialist Café: Freedom, Being, and Apricot Cocktails