Fantasy. A complex of ideas or imaginative activity expressing the flow of psychic energy. (See also active imagination.)
A fantasy needs to be understood both causally and purposively. Causally interpreted, it seems like a symptom of a physiological state, the outcome of antecedent events. Purposively interpreted, it seems like a symbol, seeking to characterize a definite goal with the help of the material at hand, or trace out a line of future psychological development. ["Definitions," CW 6, par. 720.]
Jung distinguished between active and passive fantasies. The former, characteristic of the creative mentality, are evoked by an intuitive attitude directed toward the perception of unconscious contents; passive fantasies are spontaneous and autonomous manifestations of unconscious complexes.
Passive fantasy, therefore, is always in need of conscious criticism, lest it merely reinforce the standpoint of the unconscious opposite. Whereas active fantasy, as the product of a conscious attitude not opposed to the unconscious, and of unconscious processes not opposed but merely compensatory to consciousness, does not require criticism so much as understanding.[Ibid, par. 714.]
Jung developed the method of active imagination as a way of assimilating the meaning of fantasies. The important thing is not to interpret but to experience them.
Continual conscious realization of unconscious fantasies, together with active participation in the fantastic events, has . . . the effect firstly of extending the conscious horizon by the inclusion of numerous unconscious contents; secondly of gradually diminishing the dominant influence of the unconscious; and thirdly of bringing about a change of personality. ["The Technique of Differentiation," CW 7, par. 358.]