This paper studies the conflict between critical rationalism and critical theory in Karl Popper and Theodor Adorno’s 1961 debate by analyzing their shared rejection of Karl Mannheim’s sociology of knowledge. Despite the divergences in their respective projects of critical social research, Popper and Adorno agree that Mannheim’s sociology of knowledge is uncritical. By investigating their respective assessments of this research program I reveal a deeper similarity between critical rationalism and critical theory. Though both agree on the importance of critique, they are less concerned with the development of critical consciousness as a focus of this project. In this way, Mannheim’s sociology of knowledge, particularly in its formative stages, revolves around a set of problems relatively inaccessible to critical rationalism and critical theory, since it is centrally concerned with identifying and cultivating the possibility of critique in society. In closing, I gesture to the importance of political education in Mannheim’s early work, suggesting that a return to these experimental texts will yield resources for political thought today.