The types apprehend life by opposite methods--All psychic images have two sides, one directed towards the object, the other towards the soul (idea)--The feelings of the introvert are under repression, the thoughts of the extrovert--Analytical development of the unconscious brings out the secondary function in each type--The pairs of opposites being thus demonstrated need for synthesis arises--This is a compensatory process leading to enrichment of the individual.
X. THE DEVELOPMENT OF THE TYPES OF INTROVERSION AND EXTROVERSION 437
From Collected Papers on Analytical Psychology by Carl Gustav Jung.