Freud found that the concept of different parts of the personality added considerably to the explanatory power of his model of the mind. In ‘Mourning and melancholia’, for example, he spoke of how ‘One part of the ego sets itself over against the other, judges it critically, and, as it were, takes it as its object’ (Freud 1917: 247). Later, in ‘The ego and the id’ (1923a), he used a variety of formulations and metaphors to describe the complex relationships between ego, superego and id. He refers to the melancholic, in whom the excessively strong superego has obtained a hold upon consciousness, and ‘rages against the ego with merciless violence’ or the obsessional neurotic where, ‘Helpless in both directions, the ego defends itself vainly, alike against the instigations of the murderous id and against the reproaches of the punishing conscience’ (Freud 1923a: 53). In a vivid passage he writes that the fear of death in melancholia can be explained thus:

The ego gives itself up because it feels itself hated and persecuted by the super-ego, instead of loved. To the ego, therefore, living means the same as being loved – being loved by the super-ego, which again appears as the representative of the id. The super-ego fulfils the same function of protecting and saving that was filled in earlier days by the father . . . When the ego finds itself in an excessive real danger which it believes itself unable to overcome by its own strength . . . it sees itself deserted by all protecting forces and lets itself die.