PROJECTION means the expulsion of a subjective content into an object; it is the opposite of introjection (q.v.).
Accordingly it is a process of dissimilation (v. Assimilation), by which a subjective content becomes alienated from the subject and is, so to speak, embodied in the object.
The subject gets rid of painful, incompatible contents by projecting them, as also of positive values which, for one reason or another—self-depreciation, for instance—are inaccessible to him.
Projection results from the archaic identity (q.v.) of subject and object, but is properly so called only when the need to dissolve the identity with the object has already arisen.
This need arises when the identity becomes a disturbing factor, i.e., when the absence of the projected content is a hindrance to adaptation and its withdrawal into the subject has become desirable.
From this moment the previous partial identity acquires the character of projection. The term projection therefore signifies a state of identity that has become noticeable, an object of criticism, whether it be the self-criticism of the subject or the objective criticism of
another. ~Carl Jung, CW 6, Para 783