Schizophrenia is an impossible concept. Under this heading, a number of psychoses is being grouped which have the common characteristic that the patient is, as a rule, but by no means always, fully conscious. In all other respects, no other points agree, neither in respect of symptoms, nor in respect of etiology or prognosis. Hence, there are hardly any reasons to reduce these disease patterns to a common denominator, either as "schizophrenia" or as a "group of schizophrenic psychoses". Rather, it seems more probable that schizophrenic psychoses are individual disease patterns, instead of being variations of a basic type. What is principally needed at this stage, is a fair amount of empirical research to catalog the concept of schizophrenia. Such a catalog would have to be based on exactly defined and described syndromes to enable further study whether there are any other points besides these symptoms which characterize the syndrome in question, such as etiology, pathogenetic factors, course, or response treatment. The more characteristics are found, the greater the chance that the disease pattern under investigation is really a unit by itself. In the course of these studies, and in order to avoid terminological confusion, it is advisable to use, for the time being, the term "schizophrenic psychoses", under the condition that in each concrete case this term must be supplemented by a careful typification of the symptomatology, of the etiologic factors, and of the course of the disease.