The word logical seems to mean a lot of different things. It's one of those compliments that always seems to work.Tertiary Fi is what I notice the most myself, but it is definitely not what other people notice. I have gotten enough comments that characterize me as "super-logical" that I can tell other people don't notice my tendencies towards Fi at all.
Yeah, the vagueness of the word logical is something I have thought about. I typically use it to characterize Ti (as in proceeding from the rules of formal logic), but I have noticed that other people will apply it equally to Ti and Te, as well as to Fi and Fe arguments that they happen to agree with. Sometimes I think that logical just means "sounds reasonable enough" in common parlance.The word logical seems to mean a lot of different things. It's one of those compliments that always seems to work.
I've seen the same trend with INTJ's though. Superficially they don't seem to have any Fi at all, but if you get to know them it actually takes a huge place in their lives. As Fi is introverted though you sometimes have to 'read between the lines' a bit.
Assumed that the theory is true, I think the impression grows stronger the older someone is, because Tertiary needs some time to show up.
So, here are the possible views from people who doesn't know them better, but it's just my opinion and perhaps others can help better them:
INFP: They value traditions of parents of their upbringing and want to give those to their own children.
ISTJ: Still good in dishing out, but has problems in taking it. Becomes loud and angry or sad and disappointed when "attacked". Values become higher for them.
As I said, I have written it very fast at work with my smartphone, just so that others can use it as base and correct it to something betterroud:
INFP: I think more like they get caught up in the same negative events happening, and start to become really emotional (negatively) over it instead of facing it logically and impassively.
ISTJ: I think should seem to be similar to INTJ's tertiary Fi as well. Have issues with people not seeing what they're trying to convey, and can become reclusive and withdrawn. I'm not sure if they would lash out.
Interested to hear any INFP/ISTJ thoughts on their use of tertiary functions.