How do you define Borderlines cases in Dichotomies

[IZthe411]

Let's say an ISTJ is borderline on their S/N dichotomy.

Would that mean they are closer to an INTJ or INTP in that case, or could it go either way?

If it's INTJ- that means they have use of Ni and Si
INTP means they have use of both their Si and Ne
But if they are given the specific function order of Si-Te-Fi-Ne, would they actually resemble INFP?

Just a question I've had on the brain.

 

[Thalassa]

The theories don't neatly overlap, that's the problem is trying to force them to...Functionally speaking I identify most strongly with Ne/Si beyond a shadow of a doubt, but I consider myself borderline SFP in Keirsey's theory well before ENTP or NFJ, event though SFP has Se/Ni in function theory.