Freud uses the term endopsychic perception (endopsychische Wahrnehmung, hereafter E.P.) to indicate that the ego shows it is capable of perceiving certain characteristics of the psychic apparatus - the internal world - and of its unconscious processes, and of acquiring an obscure, intuitive, unconscious knowledge of them. This knowledge manifests itself essentially in the creation of myths, in phantasy, dreams, and delusion. All these activities can reflect, through symbolic representations, the psychic processes implied in their formation. E.P. generates representations which are projected outwardly. If they are traced back to psychic reality, understood as their referential matrix, they can supply important information about mental functioning and unconscious mechanisms and processes. E.P., in short, provides a sort of unconscious imagery and symbolic form of psychic reality. Since 1909 E.P. has served as a basis for the “functional phenomenon”, discovered by Herbert Silberer, with which it has been substantially identified.