The name Carl Jung sounds familiar. I believe his work is the foundation of the personality archetypes found in Myers-Briggs personality profiles.
There are four bits assigned to each person to identify their personality.
- Introvert / Extrovert ( I / E )
- Sense / iNtuition ( S / N )
- Thinking / Feeling ( T / F )
- Perceive / Judge ( P / J )
2^4 = 16 different personalities.
Feel free to take a test if you like:
https://www.16personalities.com/free-personality-test
He developed those concepts of two different attitudes - introvert and extrovert - hence the above quote, Then functions of the mind - thinking, feeling, sensation, intuition. He also believed in a collective unconscious - I'm not too sure about that, although I fully accept his theory of unconscious association.
Thanks for the links - off to the test I go!