Carl Gustav Jung published Psychological Types in 1921. He was not designing a web quiz. He was trying to describe how people orient to the world after watching patients, colleagues, and himself. The official Myers–Briggs Type Indicator came later, built by Katharine Cook Briggs and Isabel Briggs Myers, who added a fourth pair (Judging / Perceiving) and a questionnaire. This page stays with Jung’s pieces and the eight “function-attitudes” later teachers named. Take the Jung personality test if you want a sitting. Take the 16 types test if you want four letters. They are related. They are not the same instrument.
Two attitudes
Jung described extraversion as a movement of interest toward the object — people, things, the outer event. Introversion is a movement toward the subject — the inner reaction, the idea, the impression. He did not treat these as costumes or as social skill. An extraverted scientist can be shy at a party. An introverted teacher can hold a room and still recover alone. Official MBTI language later used E and I for the same pair. Big Five extraversion is a different measurement: a continuous trait with several facets, including assertiveness and sociability, and a large research literature. If you want degree, use the Big Five test.
Four functions
Jung grouped four functions into two pairs. Sensation and intuition are perceiving functions: they take in information. Thinking and feeling are judging (he said “rational”) functions: they evaluate. A short version he used in later remarks: sensation tells you that something is there; thinking tells you what it is; feeling tells you what it is worth to you; intuition tells you where it came from and where it might go.
Each function can turn extraverted (used on the outer world) or introverted (used on the inner world). Later typology teachers wrote eight labels:
- Se — extraverted sensation — the fact in the room, the body, the live test.
- Si — introverted sensation — the present compared with a store of prior impressions.
- Ne — extraverted intuition — the field of what else this could become.
- Ni — introverted intuition — a private picture of destination or pattern.
- Te — extraverted thinking — a criterion applied to the shared world: date, metric, rule.
- Ti — introverted thinking — an inner model that has to stay consistent.
- Fe — extraverted feeling — the group’s atmosphere and obligations.
- Fi — introverted feeling — a private values compass.
Jung wrote that one function is usually more differentiated — more available, more practiced — and that the opposite function is less developed and shows more clumsily, especially under load. Later MBTI teaching built stacks of four (dominant, auxiliary, tertiary, inferior). That stack theory is community doctrine. A 16-question quiz cannot measure a stack cleanly. Read a lead result and the second-highest bar.
How this differs from 16 types
Myers and Briggs kept E/I, S/N, and T/F, then added J/P to show which function is extraverted in the type code. J types extravert a judging function (Te or Fe). P types extravert a perceiving function (Se or Ne). That is why INTJ and INTP can share three letters and still work differently: the leading process is not the same. Our 16-type page and group articles use that later map and Keirsey’s four temperaments (NT, NF, SJ, SP). This page does not. If the two sittings disagree, believe the week. Close splits are coins, not destinies.
Retest studies of MBTI often find that a large share of people receive a different type weeks later. Jung himself treated types as tendencies that can rebalance, not as passports. Wikipedia’s MBTI article summarizes the psychometric criticism: weak evidence for binary types, limited prediction of job performance, overlap with four of the five Big Five dimensions and no neuroticism scale. Use function language as a vocabulary for “how I take information in” and “how I decide.” Use the calendar for labor.
Using a result
If you lead with a perceiving function (Se, Si, Ne, Ni), ask what you systematically postpone on the judging side — a close, a value sentence, a criterion. If you lead with a judging function (Te, Ti, Fe, Fi), ask what information you skip — the live fact, the stored history, the other frame, the long pattern. That question is more useful than collecting nicknames.
Related: 16 types explained, Big Five vs Myers-Briggs, DISC.
The eight processes in a week
Se wants a live test. Si wants a method that still matches last time. Ne wants another frame. Ni wants a destination. Te wants a criterion other people can run. Ti wants the distinction to hold. Fe wants the group able to stay. Fi wants the act to stay clean. None of those sentences is a moral rank. Each one postpones something. Se postpones aftermath. Si postpones a rewrite. Ne postpones a close. Ni postpones the middle of the argument. Te postpones the feeling. Ti postpones the ship date. Fe postpones an unsweetened no. Fi postpones a request other people can schedule.
If you only remember the lead function, you will turn it into a costume. Read the second bar. Then look at the labor on the calendar. That order is the only honest use of a short quiz.