Quote Originally Posted by Urchin View Post
I think there's more variance than the formula accounts for, though, as far as how dominant dominant functions are.
That was my assessment as well. I've been trying to adapt some of the subtype theories from Socionics to an MBTI reasoning. To exemplify, I think that a given INTP could prefer to to focus more on Ne than Ti, but still not behave like an ENTP. It is because of the differing nature of how they would use it, as the dominant Ti would change how the Ne was used from what it would be if it were dominant. (dominant accepting, auxiliary producing) But I haven't managed to create reasonable correlations for the other 6 functions, so it's just a kludge at this point.
Also, I think the exact hierarchy of the lesser functions may vary a bit. I'd like to see why the "code" is the way it is.
It's almost a direct adaptation of Jung's theories for the most part (read "Psychological Types"). First, you have the dominant function and the inferior function. The opposing pairs are:

Thinking vs. Feeling
Sensing vs. Intuition

If you have one in a given pair as dominant, the other must be the most repressed, and hence the weakest, leaving the other pair to be auxiliary and tertiary. Your auxiliary function is the second most preferred function from the other pair. If the dominant function is Extroverted, the inferior will be Introverted, and vice-versa, because they will work to oppose the other. In a healthy individual, the auxiliary will also be in the opposite (I/E) realm from the dominant to allow them to deal with the opposite realm.

This defines the positions/attitudes of the Dominant, Auxiliary, and Inferior, but the reason for the attitude of the tertiary is just a guess. Some believe that an Introvert extroverts all three of their weaker functions, and an Extravert introverts all three of their weaker functions. Others (particularly Beebe) believe the tertiary is the same attitude as the dominant.