Central among the irreducible elements that define a psychoanalytic understanding of man is Freud's conception of the subject, and yet this theme remained a largely implicit one in Freud's writing. The Freudian conception of the process by which the subject is constituted is fundamentally dialectical in nature and involves the notion that the subject is created and sustained (and at the same time decentred from itself) through the dialectical interplay of consciousness and unconsciousness.

The contribution of psychoanalysis to a theory of subjectivity involves the formulation of a concept of the subject in which neither consciousness nor unconsciousness holds a privileged position in relation to the other; the two coexist in a mutually creating, preserving and negating relationship to one another. The principle of presence-in-absence and absence-in-presence subtends the dialectical movement between conscious and unconscious dimensions of subjectivity.