In his 1969 book on self-deception, Herbert Fingarette pointed out that self-deception could only work if the self was divisible, and suggested that the self is not a unit but a community of “subselves.”   Fingarette traced this theme to Plato, and saw it intensified by the New Testament polarity of Flesh and Spirit.  The multiple self flourished in medieval morality drama, which exteriorized interiority with a collection of separate characters.