This study originated from a phenomenological and speech-act theoretical concept of schizophrenic concretism. An experimental study was performed showing a highly significant lack in the schizophrenic patients' ability to use metaphors correctly. Basing on the interpretation of proverbs, the hypothesis is rejected that false interpretations of schizophrenic patients are due to intermingling of personal conflicts. On the other hand, it could be shown that concretistic interpretations of proverbs represent an avoidance of conflicts. The concepts of "substitution" and "transfer" enabled us to measure pathological concreteness and "deconflictualisation". The differentiation between schizophrenic and nonpsychotic patients was found to be highly significant. In a complementary study it could be shown that the chronic schizophrenics' disability to transfer images of proverbs to an interpersonally relevant context does not differ significantly from that of patients with their first schizophrenic episode. Discussing our empirical findings, we try to show that the concretistic reduction of thought and speech is also a paradigma of delusion. The "incorrigibility" of schizophrenic delusion was seen to be based on reification of verbal signs and metaphors. After trying to show a connection between the concretistic "Lebensform" (Wittgenstein) and the disordered intentionality of schizophrenic patients, pointers towards psychotherapeutic implications are given.