Psychological Types (The Collected Works of C. G. Jung, Vol. 6)
This autonomous activity of the psyche, which can be explained neither as a reflex action to sensory stimuli nor as the executive organ of eternal ideas, is, like every vital process, a continually creative act.
The psyche creates reality every day.
The only expression I can use for this activity is fantasy.
Fantasy is just as much feeling as thinking; as much intuition as sensation.
There is no psychic function that, through fantasy, is not inextricably bound up with the other psychic functions.
Sometimes it appears in primordial form, sometimes it is the ultimate and boldest product of all our faculties combined.
Fantasy, therefore, seems to me the clearest expression of the specific activity of the psyche.
It is, pre-eminently, the creative activity from which the answers to all answerable questions come; it is the mother of all possibilities, where, like all psychological opposites, the inner and outer worlds are joined together in living union.
Fantasy it was and ever is which fashions the bridge between the irreconcilable claims of subject and object, introversion and extraversion.
In fantasy alone both mechanisms are united. ~Carl Jung, CW 6, Para 78.