- The classical psychopathological distinction of endogenous, organic and psychogenic conditions is historically considered. In a first phase it was difficult to deal with the fundamental problem of causality. The following "ontological" phase (Tellenbach) tried to solve previous problems by means of a "positive" definition of the Endon, based on Heidegger's ideas on human existence being thrown into the world (Geworfenheit). Being non-testable, it was not followed by scientific psychiatry. Finally, the phenomenal approach tried to overcome previous limits by means of a purely descriptive approach, based on the formal description of psychopathological phenomena disclosed in any of the three conditions considered. Nevertheless, it did not succeed completely because it reintroduced a less evident but still significant form of causality. On the basis of this analysis, the main elements that new ideas on this subject should consider are discussed.KEY WORDS: psychopathology, phenomenology, philosophy, epistemology, history of psychiatry