Opposing attitudes, emotions, or perceptions of self and other that set the stage for experiences of duality influence our interactions and self–other schemas. The experience of duality that has been conceptualised as “conflict,” “self state,” and “paradox" in psychoanalytic theory has been extensively considered, particularly in terms of its manifestation in transference–countertransference relations and in the analytic material from patients' experiences. They have not, however, been compared and contrasted as entities that lead to similar kinds of experience. Scant attention has been paid, moreover, to paradox as a mental organisation that underlies certain experiences of duality. The concept of paradox has thus been emphasised and developed in this paper.