the Shadow — hidden or unconscious aspects of ourselves, both good and bad, which the ego has either repressed or never recognized.
Carl Yung, "Aeon"
a Shadow in a dream is usually presented by persons of the same sex as the dreamer. The shadow is composed for the most part of repressed desires, impulses, childhood fantasies and resentments, etc. — all those things about yourself that are not proud of. These unacknowledged personal characteristics are often experienced by others through the mechanism of projection.
"Although the presence of insight and good will the shadow can be to some extent assimilated by the conscious part of the personality, experience shows that there are certain features that demonstrate a very stubborn opposition to moral control; the impact on them is almost impossible. Resistance of this kind is usually associated with projections that are not recognized as such, and their recognition is some kind of extraordinary moral achievement. Usually if a certain part of the peculiar characteristics of shadow easily accepted as their own personality traits, in this case do not help neither the insight nor the will as the source of emotions concluded, no doubt, in another face"Carl Yung, "Aeon"
awareness of the shadow is inhibited by the persona. To the extent that we identify with a bright persona, the shadow is correspondingly dark. Thus, the shadow and the personality are in a compensatory relationship, and the conflict between them is invariably present in an outbreak of neurosis.
there is No common effective techniques of assimilation of the shadow. It's more like diplomacy or statesmanship and it is always an individual matter. First you need to accept and take seriously the existence of the shadow. Secondly, you need to be conscious of its qualities and intentions. This is due to the conscientious attention to moods, fantasies and impulses. Thirdly, the inevitable long process of negotiations.
This process of reconciliation with the other in us is well worth it because this way we get to know aspects of our nature that we would not allow anybody else to show us and which we ourselves would never have recognized.
the confrontation with the shadow first, leads to stagnation, which prevents moral decisions and makes convictions ineffective or even impossible. All becomes under doubt.
However, the shadow is not only dark side of the personality. It also consists of instincts, abilities and positive moral qualities that have long been buried or never been conscious.
Lloyd Kelton kin "Coniunctio Carl Gustav Jung"
the Flash of neurosis shakes the both sides of the shadow: those qualities and actions which are not proud of, and new possibilities that you never knew.
Yung distinguish between the personal and the collective or archetypal shadow.
"With a little self-criticism one can see through the shadow — how it is personal. But when she appears as an archetype, one is faced with the same difficulties as with the Anima /Animus. In other words, a person is able to recognize the relative evil of his nature, but it is a rare and shattering experience to stare into the face of absolute evil".