The mystical flavor of some N (and especially Ni) descriptions goes all the way back to Jung, who mostly considered the abstract/concrete component of N/S a component of I/E instead, and conceptualized an N preference primarily in terms of a special ability to perceive the contents of the unconscious and to envision, as Jung put it, "possibilities as to whence [something] came and whither it is going." Jung's Ni-dom portrait has a pretty strong
mystical visionary aspect that I don't think a typical INTJ (for example) is very likely to identify with.
And it's not uncommon for MBTI tests — both dichotomy tests and functions tests — to include one or more N questions (or Ni or Ne questions) that I suspect an NF or NP is more likely to choose the N response to than an NTJ. I'd say NTJs are the most
grounded of the N's in a number of ways, with the result that the N responses are sometimes too mystical/flaky/whatever to appeal to an NTJ.
As one example: One of the most well-known MBTI books is
Please Understand Me, by David Keirsey, and it includes a 70-question test to determine your type. The original version of the book included this question:
Are visionaries
(a) somewhat annoying
(b) rather fascinating
This was supposed to be an S/N question. Response (a) was supposed to appeal to S's, and (b) to N's. But I thought it was a poor question, because I'm a really strong N but also a pretty strong TJ, and to me, "visionary" has a spiritual new-agey theories-out-of-thin-air connotation, so I chose (a) annoying. I thought the question was better designed to separate NF's from S's than N's from S's. Well, lo and behold, it looks like quite a few NTs (and maybe especially NTJs) must have had the same problem, because Keirsey adjusted the question for purposes of the later version of the book. In
Please Understand Me II, the question now reads:
Do you find visionaries and theorists
(a) somewhat annoying
(b) rather fascinating
I still think the inclusion of "visionaries" makes it a weak question, but it's better than it was.
As another example: As I've said, I'm an INTJ with what I consider strong T and J preferences, and these Ni items from Nardi's cognitive functions test —
- Experience a premonition or foresee the distant future.
- Gain a profound realization from a mystical state or sudden release of emotions.
- Feel attracted to the symbolic, archetypal, or mysterious.
— have too much of a flaky flavor for me to relate to them very well. To identify with that kind of stuff, I think it helps to be an NF or NP (or both), and it probably also helps to be at least somewhat prone to believe in ESP and/or other supernatural stuff — as Jung was. Jung most often gets typed as an INTJ, INTP or INFJ, and the people who consider him an INFJ sometimes point to his mystical bent as one of the reasons they think he was an NF rather than an NT.
BUT NOTE: I should probably clarify that I'm not meaning to suggest that I consider it all that likely that an INFJ will have a significant mystical streak (or identify strongly with those Nardi test items) — and all other things being equal, I think a typical INFP is more likely to embrace mystical stuff than a typical INFJ. (Again, I see
both T and J as, to some degree, "grounding" influences.) But because I think an INTJ is significantly
less likely to relate to stuff with a mystical flavor, I most often point to INTJs when I'm making the point that I don't really think it's appropriate to characterize IN_Js (or NJs, or "Ni") in those terms.