In psychoanalytic theory, the notion of the person inevitably evokes the notion of subjectivity. Not that the former can be reduced to the latter; but if psychoanalytic theory is anything more a certain type of therapeutic practice, it is indeed a theory of the subject or a theory of the subjective relation. We should perhaps begin by specifying that the subjective relation must be understood as a complex whole: an intrapsychic relation, that is, a relation between the various instances that make up the subject, and at the same time an inter subjective relation, that is, a relation between (at least) two subjects. These two aspects are both inseparable and conflictual. They are inseparable because the self cannot exist, cannot construct itself without the other (whether this be a parental other or a peer). They are conflictual for at least two reasons. On the one hand, because the intrapsychic relation is by definition an arena of conflict: the conflict that opposes the Ego to the contradictory but equally tyrannical demands of the Id - which translates its attachment to the body and testifies to its inherent drives - and of the Superego, which represents its rootedness in the social and cultural sphere. And on the other hand, because this subject, which is thus divided within itself, must undergo the trial of bringing its desire face to face with the desire of the others with whom it is destined to live. The psychoanalytic theory of the subject is therefore the theory of a doubly heterogeneous relation: there is the heterogeneity of the components of the self, which go, once again, from their anchorage in somatic drives to the most ethereal expressions of the ideal; and there is the heterogeneity of the relation between this self and the self of the other. Moreover, this double heterogeneity is not limited to the matter of components: after all, these, one might think, would ideally be open to reabsorption into the homogeneity of the individual. On the contrary, this heterogeneity gives rise to a double rationality or double logic. Psychic causality - to borrow André Green's expression - is also driven by the conflict that opposes what in psychoanalysis are known as the primary processes, which Freud has described in chapter 7 of the Traumdeutung and which govern the formation and organization of the dream images, to the secondary processes, which are those processes that govern our daytime thoughts. Psychic causality is formed by the struggle for hegemony between these two logics, each of which is itself acted upon by an antagonism between what Freud, at the end of his life, called Eros and Thanatos, the urge for Life and the drive toward death or destruction.