as far as i understand it, using beebe's theories about jung's archetypes, here's why they're set up as they are - i'll use my own type as an example.
we start with the doubly-divided dichotomy of functions:
Perceiving:
N S
Judging:
T F
then apply I/E attitudes:
Ne Ni Se Si Te Ti Fe Fi
amongst these, we are necessarily going to have one that is the strongest - one that informs our worldview and provides the majority of our moment-to-moment motivation. we are also going to have a second function that provides the yin to the yang of the dominant function, as we have two function-attitude pairs to fulfill - we need one P, one J, one I, and one E - to be able to operate at all. we must be able to assess information (P), make decisions (J), attend to our inner mind (I) and attend to the outer world (E). whether we tend to pair PiJe, PeJi, JePi, or JiPe is up to chance, but whichever set it is provides the foundation for the rest of the function order.
- so to begin with, i look at the 8 functions, and find my "hero", or leading, or primary, or dominant - extraverted iNtuition.
- because my most-used function is a Perceiving function (N/S), it will need to be backed up next by a Judging function to maintain balance. also, because my first function is extraverted, my next function that provides support to the dom will need to be introverted. and understand, that this is only second in function order, not necessarily strength or skill. it simply means it will play a guiding/support role to the dominant. so i have to choose an introverted Judging function: T or F? i am F. Fi.
so now i have the most important pair, NeFi, which gives me the full code of ENFP - an extraverted Perceiver (EP) who prefers NF.
but we can run through the rest of the functions as follows:
- to take stock again, we haven't used Ni, Se, Si, Te, Ti, or Fe. because my dom was a Perceiving function, it is strong enough that it will likely override my ability to use any other Perceiving function very well - that rules out Ni, Se, and Si as tertiaries. in fact, i will tend to automatically look at anything outside of me in a Ne light, so there's no way Se will be anywhere near the top of my function order - actually, it ends up dead last. however, my Judging function, Fi, is less strong, so it can allow for the significant presence of another Judging function. but i already Judge internally, so this time an extraverted Judging function. because my auxiliary was Fi, my tertiary will balance as Te.
the reason we don't have Te-Ti, or Fi-Fe, is to keep balance... otherwise you would be left without a F or T in your first four functions, and theoretically it would be extremely difficult for a person to function without any conscious control over F or T. the former would not be able to relate to other people; the latter would not be able to think objectively. again, also, it's about roles and not strength. perhaps an ENFP will seem to be more adept with Fe than Te, but we need Te to support Fi because it provides a - well, function that the other roles cannot. Fe cannot relieve Fi very well because you cannot fully extravert Feeling while you are introverting Feeling.
but as others have pointed out, what tends to happen is that the aux and tert will be used together, and the attitude seems obvious, and the function seems obvious, but the fact that is actually TWO functions is not. for instance, an angry ENFP will tend to be very emotional and shoot a barrage of arguments at the other person. you can see the F through the non-logical elements, and you can see that it is extraverted, which would lead you to think Fe, but it's actually Te extraverting Fi - a Fi message being carried through a Te mode of delivery.
- following that, i only have an introverted Perception function left to account for, and S has not been used yet. so my fourth function is Si.
- then, because my psyche is already set up N-F-T-S in order of competency, the shadow roles will be filled similarly, simply with I/E attitudes reversed: Ni, Fe, Ti, Se.
which results in the complete set of functions paired with (mainly) jungian archetypes:
Ne "hero" - leads
Fi "supportive parent" - guides
Te "puer aeternus" (eternal child) - relieves
Si "anima" (opposite sex) - grounds
and the shadow (vicki jo, despite my usual ambivalence towards her, has wisely said: "you do not have the shadow, but the shadow has
you*")
Ni "opposing" - our primary mental hangups from resistance to using the dom "backwards"
Fe "senex" - controlling parent
Ti "trickster" - leads astray
Se "daemon" - destructive creativity
that is what i understand of the system behind it, at least. the key to order lies in the concept of dichotomies and needing to balance each individual out with its pair. much like a set of scales... tilt any scale too far and you go off the crazy end.
*in soviet russia!