Id, ego, and super-ego are the three parts of the psychic apparatus defined in Sigmund Freud's structural model of the psyche; they are the three theoretical constructs in terms of whose activity and interaction our mental life is described. According to this model of the psyche, the id is the set of uncoordinated instinctual trends; the super-ego plays the critical and moralizing role; and the ego is the organized, realistic part that mediates between the desires of the id and the super-ego. The super-ego can stop one from doing certain things that one's id may want to do.

Although the model is structural and makes reference to an apparatus, the id, ego and super-ego are purely psychological concepts and do not correspond to (somatic) structures of the brain such as the kind dealt with by neuroscience. The super-ego is observable in how someone can view themselves as guilty, bad, pathetic, shameful, weak, and feel compelled to do certain things. Freud (1923) in The Ego and the Id discusses "the general birth character of harshness and cruelty exhibited by the [ego] ideal – its dictatorial 'Thou shalt.'"

Freud (1933) hypothesizes different levels of ego ideal or superego development with increasingly greater ideals:

...nor must it be forgotten that a child has a different estimate of his parents at different periods of his life. At the time at which the Oedipus complex gives place to the super-ego they are something quite magnificent; but later they lose much of this. Identifications then come about with these later parents as well, and indeed they regularly make important contributions to the formation of character; but in that case they only affect the ego, they no longer influence the super-ego, which has been determined by the earliest parental images.


The earlier in development, the greater the estimate of parental power. When one defuses into rivalry with the parental imago, then one feels the 'dictatorial thou shalt' to manifest the power the imago represents. Four general levels are found in Freud's work: the auto-erotic, the narcissistic, the anal, and the phallic. These different levels of development and the relations to parental imagos correspond to specific id forms of aggression and affection. For example, aggressive desires to decapitate, to dismember, to cannibalize, to swallow whole, to suck dry, to make disappear, to blow away, etc. animate myths, are enjoyed in fantasy and horror movies, and are observable in the fantasies and repressions of patients across cultures.

The concepts themselves arose at a late stage in the development of Freud's thought as the "structural model" (which succeeded his "economic model" and "topographical model") and was first discussed in his 1920 essay Beyond the Pleasure Principle and was formalized and elaborated upon three years later in his The Ego and the Id. Freud's proposal was influenced by the ambiguity of the term "unconscious" and its many conflicting uses.

Id

The id is the unorganized part of the personality structure that contains a human's basic, instinctual drives. Id is the only component of personality that is present from birt It is the source of our bodily needs, wants, desires, and impulses, particularly our sexual and aggressive drives. The id contains the libido, which is the primary source of instinctual force that is unresponsive to the demands of reality.[7] The id acts according to the "pleasure principle"—the psychic force that motivates the tendency to seek immediate gratification of any impulse[8]—defined as seeking to avoid pain or unpleasure (not 'displeasure') aroused by increases in instinctual tension.[9] According to Freud the id is unconscious by definition:

It is the dark, inaccessible part of our personality, what little we know of it we have learned from our study of the dreamwork and of course the construction of neurotic symptoms, and most of that is of a negative character and can be described only as a contrast to the ego. We approach the id with analogies: we call it a chaos, a cauldron full of seething excitations. ... It is filled with energy reaching it from the instincts, but it has no organization, produces no collective will, but only a striving to bring about the satisfaction of the instinctual needs subject to the observance of the pleasure principle.

In the id:

…contrary impulses exist side by side, without cancelling each other out. ... There is nothing in the id that could be compared with negation ... nothing in the id which corresponds to the idea of time.

Developmentally, the id precedes the ego; i.e., the psychic apparatus begins, at birth, as an undifferentiated id, part of which then develops into a structured ego. Thus, the id:

…contains everything that is inherited, that is present at birth, is laid down in the constitution—above all, therefore, the instincts, which originate from the somatic organization, and which find a first psychical expression here (in the id) in forms unknown to us.

The mind of a newborn child is regarded as completely "id-ridden", in the sense that it is a mass of instinctive drives and impulses, and needs immediate satisfaction.

The id "knows no judgements of value: no good and evil, no morality. ... Instinctual cathexes seeking discharge—that, in our view, is all there is in the id." It is regarded as "the great reservoir of libido", the instinctive drive to create—the life instincts that are crucial to pleasurable survival. Alongside the life instincts came the death instincts—the death drive which Freud articulated relatively late in his career in "the hypothesis of a death instinct, the task of which is to lead organic life back into the inanimate state." For Freud, "the death instinct would thus seem to express itself—though probably only in part—as an instinct of destruction directed against the external world and other organisms" through aggression. Freud considered that "the id, the whole person ... originally includes all the instinctual impulses ... the destructive instinct as well", as eros or the life instincts.