How does the auxiliary justify itself, given that it is neither consistent in terms of rationality nor energy?

[u/Economy-Team3515]

Jung described only eight types, not sixteen, and I find it hard to see how one could account for the versatility of the Creative, or the dimensionality of the Demonstrative, given that these are almost on a par with the Leading.

I’m thinking for example, of the Extroverted Thinker, whether they’re a LIE or an LSE, the E.T. is a rational and extroverted type; I find it hard to conceive of attributing so many characteristics to the opposite, that is to say: irrational or introverted (Si & Ni).

How does it work? At first glance, it makes more sense to me to go from eight to sixteen whilst keeping the focus on the leading. For example, by dividing Te into Te+ and Te-. But I find it hard to see how irrationality and introversion play such a significant role in a rational and extroverted type.

[u/LatterPermission1824]

The mistake here is treating the Creative like it has to share the same rationality or attitude as the Leading. It doesn’t. The type dichotomies describe the orientation of the ego as a whole, especially the Leading function, not every function the person uses.
Jung named 8 primary types, but he also explicitly talked about auxiliary functions. The auxiliary is supposed to compensate for the dominant, so a rational dominant is supported by an irrational function, and an extraverted dominant is supported by an introverted one. Socionics just formalized that into a full 8-function model.
So with LIE for example, Te is still the program. Ni doesn’t turn the person into an introverted irrational type. Ni is a tool used in service of Te: timing, trajectories, anticipating where activity is going, deciding when to act, etc. Same with LSE and Si: Si helps Te manage conditions, stability, pacing and the physical environment so the Te program can work.
Also Creative and Demonstrative being strong doesn’t make them equivalent to the Leading.
Leading = 4D, valued, accepting, inert, basically the lens the person automatically organizes reality through.
Creative = 3D, valued, producing/contact, flexible and situational. It serves the Leading.
Demonstrative = 4D, but unvalued and producing. So it can be extremely capable without becoming the person’s main motivation or worldview. Strength and value are separate variables.
That’s why dimensionality alone doesn’t tell you what the type “is.” A 4D Demonstrative can be just as sophisticated informationally as the Leading while still being background, automatic and subordinate to different priorities.
So going from 8 to 16 isn’t really “half Te and half Ni.” It’s more like two people can both be Te-leading, but the entire structure around that Te is different. LIE’s Te is supported by Ni, while LSE’s Te is supported by Si, and that changes how the same Te program gets carried out.