Habermas was influenced by Sartre as was Derrida. But there is a link between Heidegger and Sartre. One of the reasons Heidegger was not tried as a war criminal despite being in charge of the Nazification of German universities was because French existentialist like Sartre vouched for him.
Heidegger -> Sartre -> Habermas/Derrida though the line is not that straight.
Richard Rorty at the University of Virginia described Heidegger as a “Nasty Piece of work” but he was still one of the ten most important thinkers of the 20th century and yet almost nobody knows who he was.
If you want to see the foundation of Post Modernism pick up a copy of Being and Time by Heidegger. If nothing else it is a good cure for insomnia.
All that said, the confluence of NAZI and Communist thought is a really interesting topic.
Thanks for that.
Was Rorty of the Critical Theory school? I had a high school friend who went to Harvard Law. We had long debates and he was always pushing Rorty’s legal writings on me. I don’t remember much about Rorty’s writings except that I couldn’t figure out what his first principles were, although I suspected that he was a Marxist.