Ego death is a "complete loss of subjective self-identity". The term is used in various intertwined contexts, with related meanings. In Jungian psychology, the synonymous term psychic death is used, which refers to a fundamental transformation of the psyche. In death and rebirth mythology, ego death is a phase of self-surrender and transition, as described by Joseph Campbell in his research on the mythology of the Hero's Journey. It is a recurrent theme in world mythology and is also used as a metaphor in some strands of contemporary western thinking.