Ti: Chase is detail oriented and logical. He doesn’t hesitate to point out when he sees a problem with other people’s logic. At most times, Chase is level-headed and calm. He cares more about details than facts, but when he’s depressed or stressed out, he neglects this dominant trait and makes perilous detail mistakes (that wind up getting him in trouble).
Se: Chase often jumps on diagnostic ideas without fully thinking them through. He’s somewhat impulsive and doesn’t always clearly think through his actions. He’s usually one of the first members of the team to catch on to visual cues that House points out on x-rays and test results. Chase can act on the spur of the moment to save a life.
Ni: Chase is the most trusting of House’s Ni predictions. Though Chase lives primarily in the moment, he usually likes to plan ahead a little. For instance, he easily foresees when his job is under threat, and strategizes accordingly. He isn’t creat at coming up with diagnostic suggestions, but usually pays more attention to symptoms than underlying causes.
Fe: When Chase is mad or upset, he may not talk about it directly, but he visibly huffs and puffs so that everyone knows about it. Chase tends to be pretty morally lax, and often differs to House’s moral judgement rather than making moral decisions himself. Because he doesn’t have defined principles, he’s easily talked into doing things (like ratting out House or kissing 8-yr-old cancer patients).
The consensus for this character is widely accepted as ISTP. However, in a couple places in the nets, I’ve seen ESTP. The reason given for this was simply that he has a lot of Fe. There is no reason that we should assume that someone is not their type simply because their lowest function is well developed.
Usually, when you’re caught between an extraverted and introverted type that uses the same functions, it’s best to look at the upper functions before coming to conclusions. In Chase’s case, I’m seeing much more Ti than Se.
He is simply a very well rounded ISTP –not something we often get to see in the media.