Projection is a general psychological mechanism that carries over subjective contents of any kind into the object. For instance, when I say, "The colour of this room is yellow," that is a projection, because in the object itself there is no yellow; yellow is only in us. Colour is our subjective experience as you know. The same when I hear a sound, that is a projection, because sound does not exist in itself; it is a sound in my head, it is a psychic phenomenon which I project. 3H Transference is usually a process that happens between two people and not between a human subject and a physical object, though there are exceptions; whereas the more general mecha-nism of projection, as we have seen, can just as well extend to physical objects. The mechanism of projection, whereby subjec-tive contents are carried over into the object and appear as if belonging to it, is never a voluntary act, and transference, as a specific form of projection, is no exception to this rule. You cannot consciously and intentionally project, because then you know all the time that you are projecting your subjective con-tents; therefore you cannot locate them in the object, for you know that they really belong to you. In projection the apparent fact you are confronted with in the object is in reality an illusion; but you assume what you observe in the object not to be subjective, but objectively existing. Therefore, a projection is abolished when you find out that the apparently objective facts are really subjective contents.
— C.G. Jung
Jung's example of yellow is worth pausing on, because it is stranger than it first appears. He is not simply rehearsing Locke's secondary qualities — he is pointing at the ordinary perceptual act and calling it, without apology, an illusion. Not a distortion, not an error in edge cases, but the standing condition of consciousness: we are always, already, projecting. The psyche does not look out at a world; it furnishes one.
What this means for the more charged territory — the person you cannot stop thinking about, the figure who carries your admiration or your rage — is that the intensity itself is a measure of how much of you is lodged out there in them. The projection is not abolished by deciding to withdraw it, because the whole mechanism rests on not-knowing. You cannot consciously project; that is Jung's sharpest point. The moment you see the mechanism, it collapses — not through effort but through recognition. This is why so much therapeutic work that operates through willpower alone misses the mark entirely: you cannot voluntarily retrieve what you do not yet know you have sent. Recognition is the only instrument that works, and recognition cannot be forced. It arrives, or it does not.
C.G. Jung·Collected Works Volume 18: The Symbolic Life·1976