Abstract
Wittgenstein likens philosophy both to an illness and to a therapy. The reflections he dedicates to mental disturbance in On Certainty shed some light on this ambivalence, by pointing at the intertwined themes of common sense, doubt, mistake, reasonableness, and normality. Wittgenstein’s remarks have sometimes been compared to the description of the symptoms of what psychopathologists have called the loss of natural self-evidence, or the loss of common sense. Besides briefly recalling some of the outcomes of this debate in literature, I focus on Wittgenstein’s conception of “hinges”, the basic practical certainties which patients suffering from the loss of common sense seem to lack. By working on this comparison, I offer an interpretation of Wittgenstein’s idea of philosophy that clarifies both its insane and its therapeutic side.