existence said:
Yet they don't consistently go with this type based approach. So I find it hard to call that the default "official" approach. Again, probably because they could never build a test or any other - strict enough - empirical evidence for that function model.
Hmm, what do you mean they don't consistently go with it? I guess to me, making a statement that your test type indicates to functions on the MBTI foundation site more or less seals the deal!
They haven't implemented a separate test for the functions, but if you believe Myers' theory, you don't need one -- you can just take the official MBTI and get your functions type (modulo problems with the tertiary).
Apparently this comes from the MBTI manual, here
http://www.csun.edu/~hcpsy002/INFJ.pdf and you can already see it's colored with the idea that INFJs are intuitive doms with auxiliary feeling.
I'm not going to say at all that the MBTI folks don't also respect the dichotomies/post tons of stats on them without always mentioning the functions next to them. However, they don't seem to view the two systems as different systems, so you more or less see both endorsed together as a whole, even if some pages are more dedicated to one or the other. This idea that one approach is validated and the other simply isn't just isn't one I've seen in literature anywhere close to official stuff.
The perspective that you should move away from the Jungian stuff seems to be in part due to certain Big 5 scientists, who showed you can interpret the MBTI scales in a Big 5 fashion, and laid criticism on both the Jungian interpretation and a strictly binary dichotomies view (in favor of a continuous dimensional view).
OK, out of curiosity, how much do you yourself define of these typology things in any solid way?
I have my preferred interpretation, compiled from reflection and studying lots of the conflicting systems, so I can say what I mean by everything, just won't pretend it is definitive, in that it might not fit certain people as well. However, this isn't a real bother, because at some level, you'll always find some organizations will fit some better than others. For example, maybe the MBTI T/F fits some better than its Big 5 counterpart, Agreeableness. Or, maybe someone's pronounced traits lie more in the combination of two scales than in an individual one. I think my current view is well-motivated and reasonable, and thus can be stated outright pretty clearly, but it's based on what dichotomies are conceptually most interesting (to me), not based on how the general populace tends to vary most frequently, for which the Big 5 ought to be deferred to.
Anyway, I guess the simplest way of summarizing what the overall position among the closely MBTI-affiliated crowd seems to be is that there's really no big conflict between the functions and the dichotomies, and that the dichotomies indicate to the functions type. It certainly isn't pro-functions anti-dichotomies, nor vice versa.
It's the pro-functions anti-dichotomies and pro-dichotomies anti-functions people who tend to disagree with this. The latter tend to a Big 5 interpretation, and the former tend to want to go more fanatically towards Jungian or socionics ideas.