"In a conversation I deliberately use the expression "negative dialectic" as a key phrase for Adorno’s way of thinking. "What does he mean by that – really?" Heidegger mischievously stretches the controversial adverb. I suggest that he understands his dialectic, in contrast to the positive Hegelian dialectic, to be a "denunciation" and a critique of what is for the sake of that about it which it is not and which is not allowed to be that way. I speak at length, perhaps too long, because I have recently published a review of Adorno’s Negative Dialectic. "One reacts critically." Heidegger’s commentary: "So he is a sociologist and not a philosopher." "But one who has more success with our ‘revolutionary’ studens than almost anyone else today. He practially causes critical protest, opposition. By reading him, it is possible to gain a philosophically supported position that is essentially a position of negation and that allows one to stand out, be different, act in reaction, agitate. Philosophical questioning in your sense is lost." Heidegger’s response irritates me: "With whom did Adorno study?" I cannot answer this question and point instead to his origin as I interpret it; that is, to his publications. Heidegger does not go into it or into my comments on Adorno’s Minima Moralia. He listens and then returns, to his question that had only been postponed, not answered, by my discussion: "No, has he really studied with someone?" "I don’t know!""
- Richard Wisser recounts a conversation with Heidegger from 1969.