You are correct. I thought I would be going too far, and also rehashing old ground by defining the difference between introversion and extroversion and how it relates to function use.
For the time being, I think it's acceptable to stack the traits. Person X is Introverted, and is Thinking/Sensing. Person Y is Extroverted, and is Intuition/Thinking, etcetera. To define a specific correlation is taking a very large step, and I hesitate because that's the kind of thing I was trying to get away from.!
I certainly agree that assigning direction to each function appears fuzzy. However, this matter warrants further consideration.
If we see that someone is clearly an Introvert, but also a clearly a Thinking type. This means that their primary modus operandi is Thinking and it operates most easily in the context of Introversion ( as we have established that Introversion represents what environment we are most easily energized in).
Thus, because the two are highly emphasized, they are inseparable from one another.
Proposition 1: Since Thinking is prevalent in the realm of Introversion, Feeling must be most supressed. (Principle of functional antithesis)
Proposition 2: Since Thinking is a judging function it is antithetical with perceiving functions (principle of functional antithesis). Therefore a perceiving function most also be heavily supressed in the realm of Introversion.
One may argue that because Thinking is the dominant function, it must be highly influential in the psyche of the Ti-Ne type.
That is true.
However, what we notice is that the Introverted Thinker is highly organized in his abstract Thinking, yet has a very low natural predilection towards organization of concrete, external entities. This means that his Thinking is not easily stimulated by the external, physical entities (therefore not akin to Te).
Te however, still mus remain very strong in the psyche of the Thinker simply becuase this is a dominant function.
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Inevitably the Introverted Thinking type is forced to interact with the external environment. However, he cannot do so by means of the Thinking faculty because it is intensely focused on the inner life and is not easily responsive to external, concrete, physically oriented stimuli. Therefore the only other way the INTP may interact with the external environment is through the perceiving function.
Thus, the salient perceiving function must necessarily be Extroverted. Once the element of Extroversion is engaged in the mind of the Introverted Thinking type, all Extroverted faculties are engaged.
Once Extroverted Intuition is engaged, the very strong Extroverted Thinking could also be engaged.
A more precise way to describe this phenomenon would be to simply claim that Extroverted Intuition has drawn Thinking outwards to the extent, or has made it possible for the Introverted Thinking to be engaged through direct external stimuli.
Hence, what we have is not an inception of a new function that we may call Extroverted Thinking, but merely Thinking starting to turn outwards.
To simplify this matter, I have before argued that Te is a dormant function, and is activated in the mind of the Ti-Ne type when Ne is stimulated.
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Another important note is the salient perceiving function for the Introverted Thinking must be Extroverted and not Introverted (as we see Ne is the strongest perceiving function, not Ni). This is the case because the influence of perceiving functions has been supressed in the inner life of the Introverted Thinking type, and because Introverted Thinking by its nature is intensely focused on the inner life, the Introverted Thinking type is forced to deal with the external world by means of perceiving faculties.