I initially discussed the concept of science and the relationship between science and knowledge, and then I will critique pure reason. This is Theodor W. Adorno's concise summary, formulated in a letter to Max Horkheimer, of his lecture on epistemology given during the winter semester of 1957/58. It is the only lecture Adorno dedicated to this central theme of philosophy, following the publication of his book on Husserl, which critiqued epistemology, the previous year. There, he developed the micrological method of immanent critique; here, he exemplarily applies it. Time and again, it is about revealing the truth in its untruth, as Adorno referred to the critique of idealism. Accordingly, the lecture not only introduces all fundamental questions of epistemology but can also be read as a grand gesture.