Seek to develop logical explanations for everything that interests them. Theoretical and abstract, interested more in ideas than in social interaction. Quiet, contained, flexible, and adaptable. Have unusual ability to focus in depth to solve problems in their area of interest. Skeptical, sometimes critical, always analytical.
I have some special expertise in this subject matter, because the INTP personality type is actually my own type. I spoke about the Eleventh Doctor, an ENTP, last time, and INTPs are the dorky, introverted cousins of ENTPs. As the description above indicates, INTPs are a highly analytical and intellectually creative personality type, ruled as they are by their urge to understand and make sense of things according to their own personal logical framework. INTPs live more in their own heads than in the physical world, as they are relentlessly contemplating ideas and generating new ideas in their heads. This also makes them, stereotypically, both quite absentminded and lazy: they prefer thinking about exciting possibilities rather than actually putting them into action. INTPs are also highly independent, both intellectually and socially, and typically crave social interaction to a lesser degree than most people.
I’ve tentatively typed one of Doctor Who’s most all-time beloved companions, Sarah Jane Smith, as an INTP (although an N.B. to this is that I’m basing my evaluation predominantly on Sarah Jane’s character in The Sarah Jane Adventures and the modern Doctor Who series, as it’s been a while since I’ve seen the classic Sarah Jane serials). I’ll admit I wouldn’t have picked Sarah Jane as an INTP at first, especially when I compare her to myself and other INTPs, but, after thinking about it, it’s the conclusion I’ve (tentatively) come to.
I’ve often seen Sarah Jane typed as an INFJ, so it’s worth beginning by detailing why I opted for INTP over INFJ. I’m definitely inclined to see Sarah Jane as a Thinking type rather than a Feeling type. While Sarah Jane, no doubt taking the Doctor as her example, holds strongly to a set of personal values which inform her worldview and guide her actions, having strong personal values is not of itself an indicator of Feeling. In any case, I’m almost certain Sarah Jane does not have high Extraverted Feeling (Fe): she isn’t highly attuned to the feelings and values of others, at least not as her first, natural instinct, nor does she particularly care what others think of her or seek the affirmation and recognition of others, as a high Fe-user would. She spent literally decades of her life in self-imposed solitude and reclusion after she and the Doctor separated, and, until she became embroiled with Maria, Luke and Clyde, seemed perfectly content with that life. That indicates strongly that she’s not an FJ type.
Rather, my impression of Sarah Jane is that she’s in fact very logical and analytical, as her dominant mode of operation. She tends to be highly rational when making decisions, and doesn’t make decisions before carefully considering all the available data. Despite being constantly engrossed in the alien and the extra-terrestrial, she brings a healthy dose of scepticism towards her work, often expressing scepticism when her young charges imagine fantastical situations involving malevolent alien intervention from things that, she insists, could easily be much more mundane. That said, she’s capable of perceiving and entertaining seemingly fanciful possibilities which her intuition presents to her, which she sets to investigating through the resources available to her and her own reason. She’s also highly inquisitive, being, after all, a journalist by vocation: she’s interested in seeking the truth, and has something of a subversive mindset in relation to powerful institutions such as governments and large corporations, treating the official platitudes of such organisations with scepticism and contempt, as in Invasion of the Bane with respect to the Bubble Shock corporation, interested, as she is, in finding the truth. This, to me, is all very indicative of the NTP type personality with Introverted Thinking and Extraverted Intuition.
More generally, what suggests Sarah Jane is an INTP to me is her lifestyle. She’s a highly independent woman, spurning the idea of working for UNIT or Torchwood. This is a very INTP thing: INTPs don’t deal well with authority and institutional hierarchy, nor do they like compromising their principles or their discretion as working for an organisation would require them to do. Sarah Jane eschews very attractive opportunities to work for UNIT and Torchwood in order to preserve her independence and autonomy. Moreover, her lifestyle in general is a very independent, and, until she became involved with Maria, Luke and Clyde (and Rani), a reclusive one—she was something of a bohemian, totally absorbed in her work. INTPs—I would suggest unhealthy INTPs—can be this way, throwing themselves wholly into some passion, whether intellectual or vocational, without feeling the need for things like love and meaningful human connection.
I anticipate that many objections to my typing of Sarah Jane as an INTP would be founded in a misunderstanding of the INTP personality. For example, that Sarah Jane spent so much of her life after parting ways with the Doctor pining after him and the life she led with him might be raised as an example of a very un-INTP thing Sarah Jane did: it seems an unusually sentimental thing for a super logical, rational INTP to do. I think such an objection would suffer from the very common fallacy of misconceiving INTPs as logical robots without emotions. INTPs feel emotions; we experience sentiment; and we can be as sentimental and intensely emotional as any other type, it’s just that we’re not comfortable trusting those feelings as part of our cognitive processes. Sarah Jane’s pining after the Doctor actually strikes me as a pretty clear manifestation of tertiary Introverted Sensing (Si): I can confirm from experience that INTPs are prone to cynically comparing the present with a happier time in the past, and find it hard to let go of memories and people (sometimes to the point of being loath to be open to new opportunities and possibilities in the present) when they’re seized by this kind of nostalgic, wistful cynicism.