Id, ego and superego

In psychoanalytic theory, the id, ego and superego are three distinct, interacting agents in the psychic apparatus, defined in Sigmund Freud's structural model of the psyche. The three agents are theoretical constructs that Freud employed to describe the basic structure of mental life as it was encountered in psychoanalytic practice. Freud himself used the German terms das Es, Ich, and Über-Ich, which literally translate as "the it", "I", and "over-I". The Latin terms id, ego and superego were chosen by his original translators and have remained in use.

In the ego psychology model of the psyche, the id is the set of uncoordinated instinctual desires; the superego plays the critical and moralizing role; and the ego is the organized, realistic agent that mediates between the instinctual desires of the id and the critical superego; Freud compared the ego (in its relation to the id) to a man on horseback: the rider must harness and direct the superior energy of his mount, and at times allow for a practicable satisfaction of its urges. The ego is thus "in the habit of transforming the id's will into action, as if it were its own."

Freud introduced the structural model (id, ego, superego) in the essay Beyond the Pleasure Principle (1920) in response to the unstructured ambiguity and conflicting uses of the term "the unconscious mind". He elaborated, refined, and formalized that model in the essay The Ego and the Id (1923).