Jungian cognitive functions were first came up with by psychiatrist and psychoanalyst Carl Jung in his book Psychological Types in 1921, based on which Isabel Myers and Katharine Cook Briggs created Myers-Briggs Type Indicator (MBTI), which enjoys great popularity in commercial use and causal self-testings by people. While MBTI has been refuted and discarded by academia due to its problematic statistical validity and test validity, the core theory behind it, Jungian cognitive functions, still has profound meaning and serves as an insightful tool in analyzing personalities and understanding people’s motivation and reasons behind their decisions and behaviors. In this article, I attempt to deduct 16 psychological types as described by Jungian cognitive functions using a series of assumptions, which explains why there are sixteen, rather than other numbers of, psychological types, and why these sixteen types are the way they are (as described by certain permutations of Jungian cognitive functions) rather than other seemingly possible permutations. This article is not an discussion of the definition of Jungian cognitive functions, nor does it attempt to prove its validity. Readers are assumed to have prior knowledge in Jungian cognitive functions.
Key words: Jungian cognitive functions, MBTI, psychological types, personality