Psychological Types (1921) presents C. G. Jung’s theory of personality differences. To explain why equally intelligent people perceive and judge the world so differently—illustrated by his divergences from Freud and Adler—Jung proposes two basic attitudes, introversion and extraversion, and four primary functions of consciousness: thinking, feeling, sensation, and intuition. Each person tends to develop a dominant function (with an auxiliary in the opposite attitude), shaping perception, judgment, and conflict with others. Jung distinguishes “rational” (thinking, feeling) from “irrational” (sensation, intuition) types, and explores their expressions in individuals, literature, religion, and history. The book links type dynamics to the process of individuation, arguing that maturity involves integrating inferior or neglected functions. Though later popularized in tools like the MBTI, Jung’s typology is richer, symbolic, and clinically grounded.
