The detachment of libido from the object transfers it into the subject, where it activates the images lying dormant in the unconscious. These images are archaic forms of expression which become symbols, and these appear in their turn as equivalents of the devalued objects. This process is as old as mankind, for symbols may be found among the relics of prehistoric man as well as among the most primitive human types living today. Symbol-formation, therefore, must obviously be an extremely important biological function. As the symbol can come alive only through the devaluation of the object, it is evident that the purpose it serves is to deprive the object of its value. If the object had an absolute value, it would be an absolute determining factor for the subject and would abolish his freedom of action absolutely, since even relative freedom could not coexist with absolute determination by the object. Absolute relation to the object is equivalent to a complete exteriorization of the conscious process; it amounts to an identity of subject and object which would render all cognition impossible. The projections we so often encounter in practical analysis are only residues of this original identity of subject and object.

Psychological Types by Carl Gustav Jung