This dissertation intends to discuss the vicissitudes of the object in borderline patients faced with difficulties involved in relationships with the object absolutely necessary at the beginning of psychic life. When this object successively fails to perform its functions adequately, in a very primitive moment of subjective unpreparedness, the psychic constitution is marked by primary traumatisms that prevent mourning and the structuring work of the negative, causing negative actions that disrupt the interior of the psychic apparatus and prevent the building up of an empty space that could make possible the emergence of representations that structure thought. By failing in its constitutive act, the work of the negative operates in a pathological way, preventing the effacement of the primary object that is consistently maintained in the psychic sphere as a result of hrough successive splittings and idealizations that crystallize and purify the object. Thus splitting consists in an unsuccessful negative action which attempts to get rid of the unrepresentable aspects linked to the traumatic experience, which threaten to return, disorganizing the fragiles intrapsychic and intersubjective boundaries. Excessive idealization, on the other hand, is a defensive strategy that gives the object an inaccessible rigid and fixed position that interferes with the work of mourning, thus resulting in the clogging of personal space and the obstruction of thought.