Jung's conception of the structure of human personality is based upon the essential antithesis of thinking and feeling, and of sensation and intuition ... he divides the basic attitude of man to his existence into two opposite tendencies, introversion and extraversion. Introversion consists in concern with subjective experience, with the person's own mental processes and the world of his own thoughts and fantasies; extraversion implies a predominant interest in objective experience, in the external world of appearances and outside reality. ... The ontrovert is not simply withdrawn or self-absorbed ... he is concerned with the meaning below the surface of all things, with the nature of reality rather than with its visible and possibly superficial appearance.