The most notable and noticeable difference would probably be in whether they like to think in terms of the theoretical or not. S types are very hands-on, concrete, down-to-earth, whereas, as we all know, N types tend to be in the clouds. INTJs are able to take their insights and actively apply them to what they're doing, because of their ability to be both practical and imaginative.
So, if your dad really likes talking/thinking about theories and ideas, he's probably an INTJ, assuming you're sure about the other three dimensions. He might also retreat into his mind quite often, in somewhat of a "spacey" way.
If he focuses more on what's readily applicable, on what's concrete and doesn't require much theory or mulling over, and generally dislikes talking about ideas and new possibilities as they relate to them, he's probably ISTJ.
Not very science-y, but the INTJs I've interacted with are very flirtatious, whereas ISTJs are not.
Would be kind of creepy if you knew these things abotu your dad, though.![]()
My dad is an ISTJ and he utterly refuses to try anything I suggest to him unless he sees that it's practical or more efficient than his current method, and he gets on me if I theorize too much about a situation we are talking about. He doesn't play games.
My brother is an INTJ and doesn't mind playing that kind of game with me. He's also more "playful" and sarcastic. My bestie's dad is an XNTJ, and also shows these qualities, in addition to the ones @subwayrider listed.
INTJs are crazier and get carried away with what-ifs. At least in my experiences.
Ive noticed that ISTJs are just better all around.
@Maven what are your dad's hobbies? Does your dad talk more about the past or the future than the average old person? Does he seem like someone who could learn to get good at chess?
this is just a personal observation according to the people I've known irl, but INTJs seem to get more anal with age and ISTJs less anal with age
He talks about both the present and the past but mostly about the present and future. Not sure if he has the patience for chess. He is more mellow than he used to be compared to a decade ago.
Ever just made him take a test online? If you ask and he's not even curious enough to do that, then ISTJ lol.
I have a coworker who I'm quite sure is INTJ who doesn't want to take any of the tests. But, this is because he has personal feelings and beliefs associated with it.