Impersonal logic is only useful in a limited set of circumstances. In such circumstances, Ti is the appropriate 'function' to use. The mistake many (young/immature) Ti-doms make is to try to force personal decisions into an impersonal framework. That just leads to either poor decision-making or an infinite loop - no decision-making. Fe might act like a crutch in such circumstances - just do what every else is doing/wants you to do (or indeed, rebel against what everyone else is doing - inferior expression does not resemble healthy expression). Your point about Ti and Fe "going extremely well together" lacks support. Each represents the other's principle blindspot. I could argue that Ti and Fi go well together because they have a shared affinity for the inner voice and the path less-travelled - thus they are not in conflict, ideologically speaking.
Ti-doms who develop Fi have another string to their bow. They can switch between the impersonal and the personal paradigm, but one will always be preferred. Ti critiques Fi-based reasoning. Fi humanizes Ti-logic. They are complementary, not contradictory.
If I can ask
1. Do you think people generally use all 8 cognitive functions and do you think the top two functions are what define a type(TiNe INTP)?
2.Do you think people have a definite Ji function, Pe funtion, Pi function, and Je function(4 definite functions) or is any of the functions up for grabs after the top two?
3.Do you think people can regularly and consciously switch cognitive functions at will(like do you think a Ti dom can temporarily became Fi dominant)?
4. Do you think some functional combinations can mimic other cognitive functions(like Se+Ti mimicking Te)?
5. When considering cognitive functions, do you consider what people do(specific actions, like organizing a desk, checking a list, solving a math problem) or do you consider why people do what they do, do you think about their core motivations?
The reason I ask some of these questions is because many people studying a subject such as this have many different interpretations of the ideas Carl Jung presented. From my understanding, the cognitive functions are complete "mindsets" people have, not some skill and ability they can automatically use when the situation calls for it. The reason I think Ti contradicts Fi is because one says you should consider your internal evaluations(Ji) in terms of impersonal, objective principles and the other says one should treat internal evaluations in terms of your deeply held personal values/feelings. I find it somewhat strange to have two Ji functions in the same person. From what I understand, you can't just mentally switch your entire mindset/worldview that easily, for this reason I actually think Ti and Fe are two parts of the same overall attitude(
I think(Ti),
we feel(Fe)), the same with Ne and Si, Se and Ni, Te and Fi. One attitude is focused on the internal aspect(let's say Ti) and the other attitude is focused on the external(Fe), one focuses it's content on impersonal evaluations(Ti) and the other on personal evaluations(Fe) without getting in each other's way. From what I understand, people have 1 thinking function, 1 feeling function, 1 sensing function, and 1 intuition function.
For instance INTP, an INTP takes a depth-based approach(introversion) to impersonal evaluation(T), a more expansive, broad-based approach(extroversion) to intuition(N). From here, it might get tricky for some people, the tertiary and inferior, the INTP has to have a sensing and feeling function(a Pi and Je function to balance Ji and Pe), again, this is from my understanding, the INTP can't have Se because it contradicts Ne, Fi contradicts both Fe and Ti. For instance, TJs and FPs might agree more on external impersonal criteria(Te), while an Ti-Fe user might have a harder time coming to agreement with Te because Ti bases it's evaluations on internally derived impersonal logic. Ti might see Te as "sloopy reasoning" because Ti takes a more depth-based, qualitive approach to impersonal reasoning. Te is most concerned about broad application, what can this do to achieve an externally based goal/standard(Je), in this way Ti could be considered to be similar to Fi because they are both more concerned with a more "individualistic" approach to their evaluations. For instance, a INTP and INFP can appear extremely similar on the surface(Ne) and can share a wealth of interests together(both are very abstract-oriented), but they can come into heavy conflict if their internal judgment functions disagree on the content of their evaluation methods(impersonal logic or personal values/ethics).
It should really be Te-Fi and Fe-Ti together(Ne-Si and Se-Ni) like with an INFP, Fi handles the personal, subjective realm and Te handles the impersonal, objective realm, granted, they would be alot more focused on the personal, humanistic side of things, but if they really did have Ti, Ti would want to do away with that criteria when making internal evaluations(Ji), Te handles the INFP's impersonal evaluations but from an external context(although they may not be as focused in that area because they are F dominant. I find this method easier when understanding jungian typology. Is it right, proven for everybody, I don't know, but it works for me now, this is not a precise, scientific subject where there's one proven, qualified standard, there's alot of different functional models. Each of us are making some basic assumptions other people might not agree with, it really depends on how you are defining these terms.