The importam variations that one notices today in the use make of the terms "metapsychology" and "psychopathology" cover noticeable différences in the meaning and the scope of these terms. In the present contribution, the authors present a reflection on the place of the invention of metapsychology in Freud's work, correlatively to a definition of psychopathology that is then provided. Indeed, we have to go back to the history of the psychoanalytic mouvement, if we want to know how psychoanalysis could have been affected by forgetting when the relation of meaning between metapsychology and psychopathology is ideotogically neglected: forgetting ahout the mnesic value of the symptom, forgetting about the function of recognition and nomination, forgetting what is involved in "projection", "transposition", "translation", "transferi" etc. The transpositions of métaphysique into metapsychology - stated notably in favour of paranóia - has made it possible to stress the role of animism and thus of a physics of psychology, transfert.