For all projections provoke counter-projections when the object is unconscious of the quality projected upon it by the subject, in the same way that a transference is answered by a counter-transference from the analyst when it projects a content of which he is unconscious but which nevertheless exists in him.16 But even supposing some trace of the projected quality can be found in the object, the projection still has a purely subjective significance in practice and recoils upon the subject, because The counter-transference is then just as useful and meaningful, or as much of a hindrance, as the transference of the patient, according to whether or not it seeks to establish that better rapport which is essential for the realization of certain unconscious contents. Like the transference, the counter-transference is compulsive, a forcible tie, because it creates a "mystical" or unconscious identity with the object. Against these unconscious ties there are always resistances-conscious resistances if the subject's attitude allows him to give his libido only voluntarily, but not to have it coaxed or forced out of him; unconscious resistances if he likes nothing better than having his libido taken away from him. Thus transference and counter-transference, if their contents remain unconscious, create abnormal and untenable relationships which aim at their own destruction.
— Carl Gustav Jung
Projection travels in both directions — that is the disturbing core of what Jung is tracking here. The analyst is not a neutral receiver. When a patient projects something the analyst has not yet seen in himself, the analyst's unconscious answers in kind, and suddenly two people are bound not by understanding but by what neither of them can see. Jung calls it a "mystical identity" — which is the older language for participation mystique, the archaic merger that precedes the capacity for genuine relationship.
What makes this passage worth sitting with is its symmetry. Transference and counter-transference are not patient-pathology and analyst-technique. They are the same movement observed from two positions. And Jung is exact about what undoes them: not insight as such, but the unconscious content becoming conscious enough to loosen the compulsive tie. The word "compulsive" matters. These are not preferences or habitual responses. They are forcible — the libido coaxed or taken rather than freely given, which is the psychic grammar of possession rather than relationship.
The final clause is almost offhand, and it carries the weight: relationships built on unexamined projection "aim at their own destruction." Not drift toward it, not risk it — aim. The movement is already inside the structure. Whatever cannot be made conscious in a relationship tends to work toward its own undoing through the relationship.
Carl Gustav Jung·The Structure and Dynamics of the Psyche·1960