The separation of parts from a whole, necessary for conscious access to the psychological functions.
So long as a function is still so fused with one or more other functions-thinking with feeling, feeling with sensation, etc.-that it is unable to operate on its own, it is in an archaic condition, i.e., not differentiated, not separated from the whole as a special part and existing by itself. Undifferentiated thinking is incapable of thinking apart from other functions; it is continually mixed up with sensations, feelings, intuitions, just as undifferentiated feeling is mixed up with sensations and fantasies.["Definitions," CW 6, par. 705.]
An undifferentiated function is characterized by ambivalence (every position entails its own negative), which leads to characteristic inhibitions in its use.
Differentiation consists in the separation of the function from other functions, and in the separation of its individual parts from each other. Without differentiation direction is impossible, since the direction of a function towards a goal depends on the elimination of anything irrelevant. Fusion with the irrelevant precludes direction; only a differentiated function is capable of being directed.[ Ibid., par. 705.]