"Where “individuality” once meant inseparability – the Latin term individuus could be used to describe friends or lovers – it now connotes personal identity, inviolable oneness. It is what sets us apart, not holds us together. The resolution of duality within the individual provides the core motif for the vast psychoanalytical literature that stems from Freud’s inference of conflicts between conscious and unconscious motivation and Jung’s dramatisation of the psychic landscape in the figures of anima and animus, the self and the shadow. At the opposite pole from the mystical, consummatory sense of two-in-one is our fear of the divided self. In Dostoevsky’s story The Double, the appearance of Mr Golyadkin’s doppelgänger marks a personality in the final stages of disintegration, as the psychic auto-immune system turns on itself. While Golyadkin struggles to preserve the modest routines on which his self-esteem rests, his double, like a fiendishly competitive twin brother, knocks away every prop."

http://www.tate.org.uk/tateetc/issue1/article7.html