To follow on: why does the MBTI focus on 8 specific archetypes when there are limitless others? It is indeed a totally arbitrary choice, and a value judgement.

To follow on: why does the MBTI focus on 8 specific archetypes when there are limitless others? It is indeed a totally arbitrary choice, and a value judgement. These are ones that Carl Jung thought particularly important based on his philosophy of personal development, and experience as a clinical psychologist. Of the ones Jung talked about MBTI further selected an even more limited set. Personally, I think it is more useful to skip the MTBI and just use Jungs original text.