As Lacan further develops the mirror stage concept, the stress falls less on its historical value and ever more on its structural value. "Historical value" refers to the mental development of the child and "structural value" to the libidinal relationship with the body image. In Lacan's fourth Seminar, "La relation d'objet", he states that "the mirror stage is far from a mere phenomenon which occurs in the development of the child. It illustrates the conflictual nature of the dual relationship". The dual relationship ("relation duelle") refers not only to the relation between the Ego and the body, which is always characterized by illusions of similarity and reciprocity, but also to the relation between the Imaginary and the Real. The visual identity given from the mirror supplies imaginary "wholeness" to the experience of a fragmentary real. See Lacan's paper, "The Mirror Stage as formative of the function of the "I" as revealed in psychoanalytic experience", the first of his "Écrits."