Originally Posted by C.G. Jung
Whereas the latter sinks to the level of a mere presentation of facts, the former evaporates into a representation of the unknowable, which is even beyond everything that could be expressed in an image. The presentation of facts has a certain incontestable truth, because the subjective factor is excluded and the facts speak for themselves. Similarly, the representing of the unknowable has also an immediate, subjective, and convincing power, because it is demonstrable from its own existence. The former says 'Est, ergo est' ('It is ; therefore it is') ; while the latter says 'Cogito, ergo cogito' (' I think ; therefore I think'). In the last analysis, introverted thinking arrives at the evidence of its own subjective being, while extraverted thinking is driven to the evidence of its complete identity with the objective fact. For, while the extravert really denies himself in his complete dispersion among objects, the introvert, by ridding himself of each and every content, has to content himself with his mere existence. In both cases the further development of life is crowded out of the domain of thought into the region of other psychic functions which had hitherto existed in relative unconsciousness. The extraordinary impoverishment of introverted thinking in relation to objective facts finds compensation in an abundance of unconscious facts. Whenever consciousness, wedded to the function of thought, confines itself within the smallest and emptiest circle possible -- though seeming to contain the plenitude of divinity -- unconscious phantasy becomes proportionately enriched by a multitude of archaically formed facts, a veritable pandemonium of magical and irrational factors, wearing the particular aspect that accords with the nature of that function which shall next relieve the thought-function as the representative of life. If this should be the intuitive function, the 'other side' will be viewed with the eyes of a Kubin or a Meyrink. If it is the feeling-function, [p. 484] there arise quite unheard of and fantastic feeling-relations, coupled with feeling-judgments of a quite contradictory and unintelligible character. If the sensation-function, then the senses discover some new and never-before-experienced possibility, both within and without the body. A closer investigation of such changes can easily demonstrate the reappearance of primitive psychology with all its characteristic features. Naturally, the thing experienced is not merely primitive but also symbolic; in fact, the older and more primeval it appears, the more does it represent the future truth: since everything ancient in our unconscious means the coming possibility.