It is at the crossroads of reality, society (represented by the superego), and biology (represented by the id). Of three agencies of the mind, the ego is in the most difficult position. These either originate in the unconscious, such as drives and instincts, or they can become "hidden" at some point in life, because people cannot bear to be aware of them, such as memories of trauma. For Freud, however, these two were just the tip of the iceberg: The largest part of the human mind is hidden-unconscious-things that people cannot become aware of easily. The preconscious may be defined as "available memory." the things a person is not thinking about "right now." but can easily remember (such as moral and social norms). In Freud's theory the id corresponds to the unconscious, the ego to the conscious, and the superego to the "preconscious." The conscious mind is what a person is aware of at any given moment (reality).
Thus, it lacks a theory describing the harmonious functioning of all the mind's faculties in a healthy person. The opposition of the id and the superego may be a reflection of a traditional Jewish psychology of fallen human beings, that within each person there is unending conflict between the "evil inclination" (yetzer ha-ra) and the "good inclination" (yetzer ha-tov). Yet as it stands, it overlooks the spiritual aspect of mind and reifies a theory of psychological dysfunction-the human mind as an arena of conflict-what religions call a state of "fallenness" (Christianity) or "bondage" (Hinduism and Buddhism). Freud's model contains many insights that have led to numerous subsequent advances in psychology. Equally, Freud's oppositional view of individual desires (id) and society's needs (superego) has been criticized. In particular, his view of the id as primarily driven by sexual desire, and his rejection of spiritual aspects to human nature, led former students, such as Carl Jung and Alfred Adler, to separate from him and develop their own competing theories. While Freud's conception of the mind as having different aspects and different levels, conscious and unconscious, greatly advanced understanding of human nature, certain aspects of his model have drawn severe criticism.
The largely conscious ego functions as mediator between the two.
The superego (also unconscious) contains the socially-induced conscience and counteracts the id with moral and ethical prohibitions. The structural theory divides the mind into three agencies or "structures:" The "id," the "ego," and the "superego." The unconscious id consists of humanity's most primitive desires to satisfy its biological needs. Sigmund Freud introduced what would later come to be called the "structural theory" of psychoanalysis in his 1923 book, The Ego and the Id.