For Jürgen Habermas, interest in knowledge goes like this: You wake up one morning and decide to buy the complete edition of Sigmund Freud's works and then immerse yourself in the study of the architecture of the ego, id and superego to such an extent that you finally create a representation of the Freudian cosmos, which Freud seems to understand better than Freud himself, but above all makes fruitful an idea that he gained from reading Freud, namely taking psychoanalysis as a model for his philosophical-critical method. In a conversation with Stefan Müller-Doohm and Roman Yos, Habermas describes this productive process in two succinct sentences: “During my first time in Frankfurt I bought the large edition of Freud. I then processed the results of this study in the Freud chapter of 'Knowledge and Interest'.”