MBTI: Lenore Thomson's Descriptions of Cognitive Functions
Introverted Function Attitudes
The Introverted perspectives draw upon our innate, inherited potential to think and understand, without regard to present-day opportunities or social conventions.
Introverted Sensation (Si)
tunes you in to the chaos, unpredictability, and unknowability of the concrete world, leading you to value whatever few signs you can find that have stable meaning. For example, the stripes of tabby cats might hold a particular meaning for you, and you might come to treasure that. As an epistemological perspective, Si leads you to view anything from outside a familiar context as dangerous and untrustworthy. You are in tune with the fact that nearly all possibilities lead to destruction. For example, if you're designing an airplane, nearly all combinations of the variables fail. Of the possible combinations of wingspan, wing placement, wing shape, fuselage shape, and so on, there is only a tiny subset that make an aerodynamically workable plane--and then only if you get a whole lot of other things just right, too. All of life is like that, only much more complicated. We live only in the small islands of the world that we've grown up with and are suited to us. And we can't possibly know why these small islands are relatively safe. As an ethical perspective, Si leads you to protect the integrity of the things and signs that we depend on. This usually takes the form of setting up barriers against the unpredictable. For example, saving for a rainy day (hardships come at unpredictable times) or inspecting buildings for fire safety (so people can trust that "being inside a building" is a sign of safety against the elements). Within these barriers, where all is trustworthy and familiar, we can survive and enjoy what is precious to us--for a while.
Introverted Intuition (Ni)
focuses on what is inexpressible--the incommensurable and chaotic things that exist outside of any conceptual framework. For example, what do you hear in the theme-and-variations movement of Beethoven's String Quartet Op. 131? There is a meaning there, but you can't put it into words. Any attempt to put it into words will result in only a tawdry parody of the reality. Better to remain silent. As an epistemological perspective, Ni leads you to view all signs as meaningless or even deceptive, not necessarily connected to what they're supposed to represent. The true reality is something that exists beyond all signs and appearances, and can only be apprehended by a kind of direct intuition. To learn truth, one must learn to see through appearances--to make contact with a reality that cannot be seen or said. As an ethical perspective, Ni leads you to hold yourself apart from and unaffected by the meanings that others attach to words and events--to keep your own vision pure and pursue your own path regardless of evidence, reasons, or the opinions of others.
Introverted Thinking (Ti)
makes sense of the world by apprehending it in terms of effects emerging from a cause, or a harmony of elements. For example, the way a beautifully made desk appears to emerge from a single idea. As an epistemological perspective, Ti leads one to trust only things that you understand first-hand for yourself, preferably through direct, hands-on interaction. You must see for yourself how a given thing or subject makes sense. Knowledge must emerge from the concrete reality itself, not from preconceived categories or criteria, and the search for knowledge must follow wherever logic and the subject matter lead, regardless of how people feel about it. As an ethical perspective, Ti leads you to do what is best for the system regardless of reward or gain or social conventions that define right and wrong behavior. For example, the sense of "natural law" that guides Clint Eastwood to do what needs doing in Old West towns regardless of the law.
Introverted Feeling (Fi)
makes sense of the world by relating everything to universal human needs and callings. For example, understanding the actions of a bully as the expression of an unmet need to be connected and feel important. Understanding that, we can see the bully without judgement: we can see him as a living being not so different from ourselves, seeking to fulfill his needs just as we do, but in a way that creates unnecessary conflict. As an epistemological perspective, Fi leads you to take whatever a person thinks or believes as an expression of that person's unique nature--not to criticize it because it fails to live up to some externally imposed criteria like whether or not it's "logical" or "appropriate". As an ethical perspective, Fi leads you to act out of empathy regardless of the social status or "deservingness" of the beneficiary. Fi leads you to view all living things as equal in value, all needing to thrive in interpersonal harmony without giving up any of their uniqueness.
Extraverted Function Attitudes
The Extraverted perspectives lead you to use present-day opportunities and circumstances as the ultimate building blocks of your beliefs. Extraverted perspectives provide ways to negotiate through the present-day world, making sense of situations quickly and knowing where you stand in relation to them and what you want to do.
Extraverted Sensation (Se)
makes sense of the world by attending to what exists concretely here and now, and trusting your instincts. As an epistemological perspective, Se leads you to believe only in what you can see and experience concretely, and to trust your immediate, gut-level responses to it. If it looks like a duck, walks like a duck, sounds like a duck, then it's a duck. Whatever a sign means is obvious and inescapable; if a sign's meaning is not obvious, then it's meaningless. Whatever is physical, immediate, gut-level cannot be faked and must be right. For example, if you sense that someone is up to no good, then you trust that sense. If you have an impulse to paint the town red, then you go out and do so. As an ethical perspective, Se leads you to believe that life is to be lived right now, "in the moment", responding to things immediately and without thought. What matters most in life is what makes the biggest perceivable impact, whatever stands out in a way that can't be ignored. Se leads you to develop a persona that is attractive and "hip" according to the conventions of your society and your time--to go with the flow without stopping to question the direction. If something isn't fun, then don't do it.
Extraverted Intuition (Ne)
makes sense of the world by seeing ways to incorporate what is known into a broader context--breaking through the limits of current concepts. For example, sensing, before nearly anyone else, that high-bandwidth communication networks would "change the rules" of commerce. As an epistemological perspective, Ne leads you to practice "out of the box" thinking. There are never any final answers, just more and more opportunities to shift concepts and make sense of things in new ways. Whatever we think things mean today, we'll probably find out tomorrow they mean something different. As an ethical perspective, Ne leads you to take risks and dive into the unknown--stacking the deck to some extent by diving into areas that look especially fertile, but genuinely entering the unknown and allowing it to send your mind in new directions. If you don't know, just guess! Try something, and information will come to you--but only if you stir up the pot. From an Ne perspective, life is a succession of opportunities to pounce on, each opportunity opening up more that you can't yet see.
Extraverted Thinking (Te)
makes sense of the world by viewing things "objectively": in terms of categories and measurements that can be defined in advance of observation. For example, defining the specifications of a wheel that make it acceptable for use on the road. Stable categories and measurements enable people to define shared goals and enforce agreements fairly. You can tell whether the wheel met the specifications or not; anyone can tell, because the specifications are defined independently of both the wheel and the person doing the measuring. As an epistemological perspective, Te leads you to be concerned with logical and empirical justification. No conclusion may be accepted until it has been grounded on a firm foundation of other facts that have themselves been firmly established. What has not been tested is unknown; what cannot be tested is meaningless. As an ethical perspective, Te leads to a life of "rational hill-climbing": making every decision according to well-defined criteria for what counts as better and worse. You might not know how to get to your goal, but at each decision, you take the choice that leads closer to it: you improve your position at every opportunity. Moral codes in a Te worldview emphasize keeping one's promises. Justice is understood as a social agreement negotiated by all parties, which specifies rewards and punishments that must be enforced fairly according to objective rules.
Extraverted Feeling (Fe)
makes sense of the world by viewing it in terms of where you stand with other people: interpreting signs that indicate the category of your relationship. As an epistemological perspective, Fe leads you to view every sign as an expression of people's loyalties. A simple example is that displaying a flag demonstrates your loyalty to country. What matters is how you go above and beyond efficient means to an end. For example, throwing a party in someone's honor is not "necessary" for survival: it's a gesture that goes above and beyond survival, expressing your feelings for the guest of honor in a way that all can understand. From an Fe perspective, words are never neutral descriptions of fact: your choice of words, your choice of topic, is a declaration of your feelings and loyalties. As an ethical perspective, Fe leads you to believe that "life is with people": to understand one's value and meaning in terms of your standing in the community--in terms of the people whom you influence and their feelings about you.