This study in the philosophy of psychiatrydeals with the concept `psychosis'. Methodologicallyit follows Wittgenstein's proposal to `dissolve'philosophical problems by studying the actual use ofthe relevant concepts. Philosophical problemsconcerning both identification of psychosis and themeaning of this concept are pointed out. The logicaldependencies between `psychosis' and `understanding'and between `understanding' and the concept ofperson are demonstrated. Studying theinterdependence of these concepts in the light ofthe actual uses of `madness' shows how the use of`psychosis' implies a radical loss of understanding.The status and legitimacy (...) of `psychosis' as a psychiatric concept is then demonstrated. (shrink)