Dominant Fi: The Doctor doesn’t believe that morality should be enforced, but always gives his enemies the opportunity to choose, often at great cost to him. He discards personal questions and refuses to spill anything about his inner-self. Nine has more difficulty dealing with interpersonal conflict and moral choice than most of the other regenerations. He doesn’t like anything to get “domestic,” and doesn’t always have an immediate response to emotional jabs. He is quick to deal out punishments when he or people he loves have been wronged. When it comes to decisions that bear a heavy moral weight, he sometimes comes to a stalemate in which he finds it difficult to make choices when he’s aware that it will affect other people. The Doctor will not do anything that violates his moral code, no matter what is at stake. derives his morals from within himself and the universe, rather than from any given society. Though reserved about his inner-life and often reluctant to accept other people’s friendship, the Doctor is typically friendly and doesn’t hesitate to touch people on first meeting. The Doctor is perfectly aware of his cleverness and doesn’t hesitate to make this known to others.
Auxiliary Ne: The Doctor is reluctant to carry along friendships unless he can see the potential in the individual. He thrives off of new ideas and is willing to accept anything as a possibility. The Doctor is incredibly adaptable and jumps into new situations with little hesitation. He sees all in terms of the big picture, and sometimes misses the little details. He wants to find meaning in everything rather than simply looking at the facts and this allows him to embrace the many cultures and mentalities the he encounters. The Doctor relies heavily on his intuition and even after he’s already come to conclusions, he’s still open to more possibilities. The Doctor gets bored when his mind isn’t occupied by new things and needs constant exploration. His sense of humor is rather off-beat, and he can often seem rude by appearing to disregard other people’s feelings.
Tertiary Si: Nine has a difficult time letting go of the harsh memories in his past. When he first meets the surviving Dalek, he reacts with intense emotion and it takes him a long time to get past what happened to his people. He’s incredibly sensitive about this past, and refuses to speak about it because when he does, the associated emotions are stored up within him. The Doctor doesn’t always notice his surroundings because he’s so fixated on the big-picture. For instance, right after he meets Rose and he’s unknowingly looking for the London Eye, Rose points it out to him, but he has to look over his shoulder many times before he finally notices it. The Doctor has a huge store of memories, which he draws upon to help him in his problem solving.
Inferior Te: The Doctor can be very rational and objective when he needs to (though all of his decisions are made based off of his internal moral code, rather than logic). When he considers logic, it is always externally based and not derived from within himself. The Doctor is incredibly adept at critical analysis and knows how to organize people. He doesn’t make long-term plans, but rather, relies on a firmly held set of principles to chart his course.
There appears to be a great deal of argumentation about this Doctor’s MBTI. Most either claim him as an INFP or an ISTP, and some idiots (probably the wannabe-INTJs) have actually gone so far as to call him an INTJ.
Can’t be an INTJ –way too much hugging for that. Besides, he reeks of Ne. Can’t be an ISTP or INTP because he reeks of Fi. Has to be an NF type, but too spontaneous to be a J. Therefore, INFP.
Neil Gaiman would be happy about that.