One of the latest topics in contemporary psychiatry, the effort to strictly define the concept of "schizophrenia"" holds a core position in the author's psychopathological research. From studies on the place of the other in delirium. the author attempts to ponder, more particularly from the "quasi spatial" or topological standpoint, how the other emerges in the field of deliriant experience of schizophrenics and non-schizuphrenics.