Wittgenstein likens philosophy to both an illness and a therapy. What seems an ambiguity is actually a complex dialectical relationship, in which common sense plays a crucial role. My aim is to research common sense in order to clarify this relationship. I will do so by comparing Wittgenstein's reflections on these issues with what in psychopathology has been named "the loss of natural self-evidence", or "the loss of common sense". Section 14.1 sets the scene, introduces the theme of common sense, and focuses on radical doubt as a philosophical disease. Section 14.2 describes in more detail Wittgenstein's notion of "hinges": these are common sense and practical certainties, doubt about which, in ordinary circumstances, is unreasonable. Building on prior literature in the psychopathology and philosophy of psychiatry, I argue that doubts about hinges can indeed characterize the early stages of schizophrenia. After developing the comparison between schizophrenia and philosophy as illness, Sect. 14.3 deals with the therapeutic side of philosophy: I argue that Wittgenstein's point is to call for a "de-epistemicization" of life and the rediscovery and strengthening of practical trust.