Reblog: How INTJs & INFJs Approach their Body & Physical Needs

Personality Junkie has published a very good article about INTJ/INFJ physical needs.


The Classification of Individuals Means Nothing

“The classification of individuals means nothing. Nothing at all. It is only of an instrument value for the practical psychologist” 0:55


There are many INFJs who have tested as INTP before discovering their type (including myself) and INTPs who have tested as INFJ. The two types are very different from a theoretical point of view because they belong to different temperaments (Rational INTP and Idealist INFJ) and have different attitudes towards the world (J and P). The two types share only two cognitive functions and it would seem like there is little reason for indecision between these types. If we base similarity on the common shared functions alone, the two types share only Ti and Fe. It seems more likely that an INFJ would mistype as ISTP (Ti Se Ni Fe) and INTP as ISFJ (Si Fe Ti Ne). But that is not usually the case, INFJ and INTP are more similar than they appear on the surface.

Here are the cognitive functions for these two types:

INFJ: Ni Fe Ti Se

INTP: Ti Ne Si Fe

The Similarities


INFJs and INTPs can exhibit similar behaviors. As intuitive introverts (INxx), both types can detach from the external world and escape into their minds. They can also appear clumsy and may have poor physical coordination because their sensory functions are relatively weak. They may also display similar interests in intellectually stimulating topics such as philosophy, science, mathematics and may work in fields that require little interaction with their immediate physical environment.

The T/F Dichotomy

The third letter in the MBTI type determines if a person is a feeler or a thinker. The terms can be confusing because every person needs to think and feel inorder to function. There is a similar personality theory known as Socionics, that uses more descriptive terms to differentiate this dichotomy.

Feelers value ethics in decision making.

Thinkers place emphasis on logic in decision making.

The two cannot be mutually exclusive. A shallow understanding of Jungian typology has led to the following misconceptions:

  • Thinkers have no feelings, Feelers can’t think
  • Thinkers are bright, Feelers are dumb
  • Thinkers are indifferent, Feelers are compassionate

These stereotypes are not true. One can be a compassionate Thinker and a logical Feeler. They are easily dismissed as one dives into the cognitive functions. INTPs who are drawn to people or altruistic causes may type themselves as INFJ and INFJs who have intellectual interests may type themselves as INTP on the basis of the T/F dichotomy.

The J/P Dichotomy

I have mentioned the reason behind the Judger/Perceiver dichotomy in previous posts. On the surface, it may appear that Js are more organized than Ps and Ps are more open-minded than Js. This may apply as a general rule for most types but it is more complex in the case of INTPs and INFJs. You can read about the difference between J and P in this article.

Most of the common J traits do not necessarily apply to INFJs. INFJs may not organize their physical environment, follow routines or manage their time as well as most Js. Ps are known for procrastination and being scatter-brained but INTPs can be very focused and determined when they are intrinsically motivated to accomplish a goal.

Thought Patterns

The dominant cognitive functions of the two types are similar. Both Ni and Ti are objective and concerned with systems. The objectivity of Ni stems from its universal nature and intolerance of biases in its pursuit of the truth. Ti strives for thought precision and logical coherence therefore it openly questions thought processes and doubts itself to reach a state of self-assurance and harmony.

In INFJs, Ni can manifest as understanding people and minds. The tertiary Ti is used to organize the insights provided by Ni into a logical structure for coherence.

In the case of INTPs, Ti creates a curiosity for knowing how things work. The dominant and tertiary functions can work together to synthesize an internal model of the world.

For this reason, the two types can become great thinkers and are found abundantly among philosophers.

Cognitive Function Development

The development of the tertiary (3rd) and inferior (4th) function takes place in early to mid-adulthood, during the period when most people discover their type.

The tertiary function can be thought of as a crutch the mind relies on to reinforce the most active dominant and auxiliary functions. If the person is in the process of developing this function, it can become the most conscious process as it uses most of the person’s psychic energy. INFJs in their late teens or twenties who are developing their tertiary function can become aware of Ti because it is a conscious linear process as opposed to their dominant Ni which may not be noticed because they naturally “swim” in it as fish swim in the sea. During this time, INFJs will find it easier to articulate their insights and communicate them in a logical manner. If coupled with self-discovery, this function may feel like it is the dominant because it gives Ni its voice and allows their previously unconscious mental processes to come to light. If the INFJ engages in intellectual pursuits such as Academia, his/her tertiary function will get the opportunity to flourish and may feel indistinguishable from Ni. Many INFJs mistype themselves as INxJ or INTP because they believe they are both feelers and thinkers.
However, the two functions are very different as I will demonstrate in the next section.

The inferior function, also known as the aspirational function is usually the weakest and least developed cognitive function. It can become a source of insecurity if the person is immersed in an environment that requires the great use of this function. People also tend to overestimate the strength of their inferior function because they spend much effort in using it and developing it. In the case of INTPs, the inferior function is Fe, which is concerned with appropriate social behavior and taking care of others’ feelings. Fe is important for initiating and maintaining social relationships and is very important from an early age. It is common for young INTPs to unintentionally offend others because they may not have insight into what is considered socially acceptable. This is usually learned through trial and error (Si) and observing behavioral patterns (Ne). Social life requires them to spend more effort than other types in developing their inferior function so their inferior function may appear “stronger” than the inferior function of other types. It is rare for INTPs to immerse in Fe as it conflicts with their dominant process so it it usually manifests unconsciously. Most INTPs learn to feign Fe and adjust to their social environments using their auxiliary function (Ne). INTPs may mistype as INFJs, if they have developed their inferior function (Fe).

The Differences

Cognitive Functions

Contrary to what the letters suggest, INFJs are dominant perceivers ([Pi) and INTPs are dominant judgers ([J]i).

As introverted perceivers, the internal world of INFJs is dynamic and ever-changing. In the INFJ, Ni is used for building complex systems that are universal. When Ni gathers external information, it molds itself with the new data to lead to greater understanding. INFJs are known for analyzing situations from multiple perspectives to get a clear perception of the situation at hand. They may disregard their personal beliefs and convictions to deal with pragmatic concerns in the external world. Ni provides an intuitive understanding of situations but it is usually a means to an end and not an end in itself.

INTPs can store an enormous amount of knowledge because they can easily archive and organize the information they perceive (Si) as they form their opinions using their internal set of logical principles. Ti creates a coherent internal model of the world as perceived via Ne, to help the INTP gain an understanding of the world.  INTPs expect new data to make sense before accepting it into their internal world. They usually strive to understand the inner workings of systems to gain a clear understanding of the world. INTPs pursue learning as an end in itself and may accumulate a large amount of information over a lifetime. They value their internal model more than its compatibility with established facts and they may dismiss new evidence to maintain internal harmony. A famous example of this Albert Einstein’s refusal to accept non-deterministic interpretations of Quantum Theory stating “I still do not believe that the statistical method of the Quantum Theory is the last word, but for the time being I am alone in my opinion.”

Precision vs Accuracy

INFJs can tolerate vagueness, ambiguity, logical paradoxes and incoherence because their dominant function is unconscious and not always subject to the restrictions of conscious thought. They can emerge with seemingly spontaneous insights but maybe unable to describe the thought processes that led to their convictions because of the irrational nature of intuition. They cannot easily form their opinions on non-urgent matters because they tend to view things from multiple perspectives, and it is not unusual for their opinions to change as they gather more data.  Arriving at the “one truth” is more important than maintaining a solid worldview. It is common to hear responses such as “Depends, Probably…” on questions of truth and falsehood.

INTPs value precision and clarity of thought above all else. Therefore, they may filter the information they perceive to make it compatible with their internal logic. The binary nature of their dominant function, Ti requires complete integration of new information before they accept an idea as valid.  They are usually aware of the reasoning behind their actions because Introverted Thinking (Ti) is a conscious function. They can also easily validate information against their internal logic and form quick judgments on arguments from other people. They are more definite in their responses and feel more comfortable making absolute claims, “X is true, Y is impossible”.


INFJs have strong convictions about external matters (values, vision, goals..) based on their irrational perception (Ni) but may not be able to defend it using their tertiary thinking function (Ti). They are the most intuitive type and they trust their insights as they rely on them for most of their lives. They may be unwilling to reconsider their views because they value “intuitive sense” over logic. As a result, they may come across as stubborn and inflexible with their opinions. However, they may radically change their views if there is a change in their intuitive perception.

INTPs have a good understanding of how the world works and can easily discern patterns they observe. The external attitude of their perception function (Ne) makes them flexible and open to change with everyday matters. However, their internal logic is personal and they place heavy emphasis in keeping it coherent. They can have a personal attachment to their logic and may be hesitant to share their deepest convictions for fear of exposing it.  They have the ability to detach their emotions and analyze external situations from an “objective” perspective. However, their need for a consistency may lead to self-doubt if their assumptions are challenged by external evidence.


As I discussed in the INFJ vs INTJ article, INFJs and INTJs belong to different temperaments.

INFJs are Idealists and are concerned with the animate world of beings.

INTPs are Rationals and are interested in impersonal systems that are open to objective inquiry.

For this reason, INFJs are usually driven by a cause (Ni) or a need for change (Fe) when they tackle intellectual problems. They are goal-driven and usually pursue interests that will help them achieve their social goals. They are usually attracted to Art, Philosophy, Writing, Poetry, Social Sciences…

INTPs are driven by curiosity and a need to create an objective and consistent model of the world. They think for the sake of thinking, and pursue their interests to gain a clearer understanding of the world. Their interests can include the humanities, but they tend to be attracted to theoretical “hard sciences” such as Pure Mathematics, Engineering, Architecture, Computer Science…


Both INFJs and INTPs can be very creative. INFJ creativity is symbolic and inspired by Introverted Intuition (Ni) where INTP creativity is synthetic and gathered through Extroverted Intuition (Ne).

INFJs can be gifted writers and poets because they can channel their insights (Ni) into aesthetic works of art (Fe). Their creative process is mostly unconscious and uses archetypes, abstractions and symbols.

INTPs can be excellent theorists, mathematicians, and intellectual revolutionaries because they have a broad imagination (Ne) and are able structure their perceptions into a logical form (Ti).  Their creative process requires effort and concentration and conscious manipulation of mental entities.

Perception of Time

INTPs and other xNPx types have a detached perception of time and tend to see the past-present-future as a continuum. They have a historical perspective and set their goals to accumulate memories and achievements that can be viewed from an autobiographical context.

INFJs and xNJx types have a future directed perception of time where the past and present are seen as contributing factors to a vision. They view time as a finite resource and strive to accomplish their goals to directly experience the success in the limited time they have.

Jungian Types and Perception of Time

Jungian Types and Perception of Time


INFJs are less verbose than INTPs and may struggle with expressing their ideas in words because their thought process is not always linguistic. They have the ability think in feelings, images, symbols, hunches… so it is hard for them to articulate the thought process that led to their conclusion. They can also make intuitive leaps between ideas and miss details in their arguments.

INTPs are very articulate and careful with their word selection. They can convey their thoughts in a clear fashion and are very good at explaining material to another person. They try to convince themselves as much as the other person when they are trying to get a point across. Their speech tends to be slower than Extroverted Thinkers but it is coherent and easy to follow.


Internal World Dynamic Static
Drive Vision Curiosity
Understanding Intuitive Logical
Goals External World (Fe) Internal World (Ti)
Creativity Inspiration Imagination
Speech Terse Elaborate and Verbose

INFJ vs INTJ Part 2

Tertiary Functions

In introverted types,  Introverted Judging [J]i function is responsible for organizing the internal world.

Dominant introverted judgers such as INTP/ISTP and INFP/ISFP create an internal model of the world and filter their perceptions to harmonize with it. They spend most of their energy re-organizing their internal world to maintain harmony or consistency.

INTJ and INFJ are dominant perceivers, despite the J in the letters. They do not have a solid internal model but a constantly evolving network of perceptions and insights that serves as a tool for understanding the world. The fluidity of Ni requires an introverted judging function to maintain a degree of stability and sense of self.

INFJs use Ti as their tertiary function.

INTJs use Fi as their tertiary function.

The different tertiary functions are responsible for the differences in decision making processes and thought patterns between the two types.

Decision Making

In most types, the tertiary function serves as a crutch when the first two functions fail to meet the demands of the environment. Ni dominants rely on their extraverted judging functions (Te/Fe) to deal with novel situations in the environment. The extraverted judging processes conform to commonly accepted methods of thought and behavior. In INFJs, this takes the form of subscribing to social values and behaving appropriately. In INTJs, it is seen as reliance on established facts and accepted modes of thinking. These objective judging functions are usually sufficient for most situations. However, these functions can be challenged when the person faces a challenge that requires decision making on subjective grounds.

The INFJ that is accustomed to using Fe may not know how to decide when presented with multiple options that are equally appropriate or have similar effects on others.

The INTJ that has relied on objective facts may not know which path to take when presented with questions on matters that cannot be verified through empirical means.

In these situations, the person retracts into the internal world and relies on the tertiary function to present a solution. This is especially stressful in [P]i (Ni/Si) dominants because both the auxiliary and tertiary function are judging functions and are opposed to each other. (Fe/Ti in INFJs and Te/Fi in INTJs) The extraverted judging functions have a quality of urgency but the introverted judging functions are complacent and take time to process. In addition, the functions are opposed (Feeling vs Thinking) so the person will need to suppress one for the other to function.

For example:

An INFJ and an INTJ have been invited to different social events they find equally interesting may have trouble deciding which one to attend.

The INFJ will initially use Fe to consider the importance of the person who invited her and how it would impact their relationship. She will project how the decision will affect her social relationships, public image, the amount of  social interaction involved and her preparedness for the environment (attire, mood, etc…). If she is unable to make a decision based on these factors, she turns to her tertiary function, Ti  to analyze her options. She will reflect on her worldview and philosophy to find principles (Ti) that reinforce her visions and goals (Ni). She may consider what she would learn from the events and how it could help her achieve her goals or refine her understanding of people or the world.

The INTJ will consider the convenience and pros/cons of attending the events. He will use Te check if they are compatible with his schedule and the plans he has made for the day. He will think about how the events would benefit him and which would yield a greater return (in tangible goods or simply pleasure) on the time and cost invested. He may consider the location of the events, the risk of accidents and other mishaps, and the worst and best possible outcomes. If Te does not provide a good reason to choose one over the other, he will come back to himself and reflect on his personal values (Fi) and how each event harmonizes with it. He will introspect on the reasons behind his interest in the events and think about how it would help him understand himself better.


INFJs values usually resonate with their surroundings and prefer to subscribe to an external standard (Fe). Their values are usually learned from an early age and they usually reflect the cultural environment they were raised in.  When it comes to moral decisions, INFJs are flexible and may adjust their beliefs to adjust for the situation. They may analyze situations based on group dynamics, individual differences, and other measures they can use to plan their speech and actions. (Ti). For this reason, they can explain their decision making process more easily than INTJs. Relationships and one-on-one communication can be stressful for INFJs because they create models of how other minds work, and they adjust their attitudes and opinions to fit other individuals’ needs. Their moral decision making can be intellectual and they may suspend their immediate instinctual reactions to sudden events to predict which actions lead to the greatest good. They expect their values to be universal and may set high standards for themselves and others to reach their external ideal.

INTJs base their values on internal standards of integrity, self-honesty, charity and other virtues that revolve around their sense of self. (Fi) They usually have a strong will and are aware of their wants and preferences from an early age. When it comes to relationships, they have an easier time evaluating others and deciding if a person meets their standards. (Te) Competence is a core value shared by most INTJs, they value independence and ability in themselves and others. For this reason, they devote much of their energy mastering skills and assessing themselves using objective methods. If their Fi is well developed, they may have a fascination with ideals such as universal good and evil. They like to have freedom in making moral decisions and can sometimes despise societal values they find pointless. When confronted with decisions that require quick moral judgment, they turn to their heart and make decisions based on what feels right (Fi) despite the resistance of their intellect (Te). When it comes to people and relationships, they judge people based on their qualities and are more comfortable with dismissing those with different values.


INFJs use Ni-Ti to form their ideas and express them through Fe.

INTJs generate interest using Ni-Fi and think through Te.

INFJs tend to be terse and dispassionate (Ti). They craft their thoughts internally and express them in an appropriate fashion (Fe). Their speech is brief and they may pause between sentences when they are processing. (Ti) For this reason, they usually prefer writing to speech because it gives them time to choose words, tone and other subtleties.

INTJs are verbose and direct. They can be passionate about ideas (Fi) and may disregard tact and others’ feelings because they organize their thoughts as they speak. Their speech has a flow and they can instantly organize their ideas into bullets or numbers. (Te) They prefer to make charts, graphs, and drawings to share their explicit logic.


Cognitive Functions Poster

Jungian Cognitive Functions

INFJ vs INTJ Part 1

There are some people who cannot decide if they are INFJ or INTJ. I have come across people who have succumbed to typing themselves as INxJ, a hybrid that cannot exist according to cognitive function theory. If you are one of those people, it is likely that you believe your T and F are very close to each other or that they are balanced. But as I have mentioned in a previous post, the MBTI is not a trait theory and does not measure preferences quantitatively.  I will compare the two types and show key differences between the two to help you decide.


Kiersey lists four temperaments:

The Guardians (ESTJ, ISTJ, ESFJ, ISFJ)

The Artisans (ESTP, ISTP, ESFP, ISFP)

The Rationals (ENTJ, INTJ, ENTP, INTP)

The Idealists (ENFJ, INFJ, ENFP, INFP)

As a shorthand form, we use NT for The Rationals and NF for The Idealists based on the letters common to all types in each temperament. You can read more about the theory here.


INFJs are attracted to the animate world and strive to change the world for the better.

INTJs pursue intellectual interests and prefer to deal with the impersonal aspects of the world.

This distinction made by animate and impersonal is similar to the general difference between T and F types. If you strongly identify with The Rationals or Idealists, you probably belong to that temperament. You may find that you share characteristics with both Rationals and Idealists. There are many intellectuals (Ludwig Wittgenstein, Arthur Schopenhauer, Plato…) who would probably test INFJ and Idealists (Jean-Paule Sartre, Sigmund Freud) who would probably test INTJ. I find that INTJs may have an easier time deciding their temperament than INFJs who may classify themselves as a hybrid of both temperaments. I will discuss the reason for this in the next section.

Cognitive Functions

Dominant: Introverted Intuition

Ni (Introverted Intuition) is primarily an unconscious process that surfaces with solutions to novel problems and insights. It works by abstracting and extracting symbolic meaning from everyday experience and combining it with unconscious archetypes to provide insight and “meaning”.

Make sure you are certain if Ni is your dominant function. Some INFPs identify with both INFJ and INTJ and may decide they are somewhere in between. You may want to look at the previous article INFP vs INFJ if you also think you maybe INFP.

As dominant Ni users, INFJs and INTJs are driven by a desire to realize their internal vision in the external world. However, unlike other types that share dominant functions (for example, ISFP and INFP), the dominant function expresses itself in differently in the two types.

The two types experience Ni in different ways.

In INTJs, Ni is experienced as “aha” moments of insight. They are natural problem solvers so it also serves as a system builder that connects patterns and predicts their future consequences. Ni is cerebral in the INTJ and it helps them think in novel ways. Some INTJs report thinking in images, symbols, connections and other processes that are difficult to verbalize. It seeks to explain the reason behind phenomenon and get a clear vision of how things work. It fuels the INTJ with curiosity and creates their interest in the sciences. It is attracted to complexity and problem-solving.

In INFJs, Ni is visceral and presents itself primarily through feelings. They experience it as strong visions of the future and very strong feelings about people and situations. It also helps them the INFJ in academic environments or when dealing with intellectual problems. However, Ni is more likely to provide the final result than consciously guiding the problem solving process as in the case of INTJs. It is primarily driven by finding meaning in the world and creates interest in philosophy and the arts. It is attracted to abstractions and “the whole”.

If you believe your thought process is guided by visual imagery and relationships, you are probably INTJ.

If you believe your feelings about things help you understand the world, you are probably INFJ

Auxilliary Function: Extroverted Judging

INFJs and INTJs share the same perceiving functions Ni and Se, but have completely different judging functions (Fe/Ti and Fi/Te). It is rare, if not impossible to have full use conflicting judging functions (Te and Fe, Ti and Fi) simultaneously because they are diametrically opposed.

Here is the function order for the two types:

INFJ: Ni Fe Ti Se

INTJ: Ni Te Fi Se

As introverted dominant perceivers ([P]i), INFJs and INTJs have an auxilliary extroverted judging function, Fe and Te respectively. The letters T and F are determined by the most dominant extroverted function.
Te (Extraverted Thinking) creates strategies and makes decisions based on effectiveness, efficiency, sustainability and other objective measures of performance. It is pragmatic and is useful for planning, logistics, time/resource management and other tasks that require “real world” problem solving. It validates its decisions based on empirical data and quantitative measurements and constantly searches for areas of improvement.

Fe (Extraverted Feeling) makes decisions based on values and their direct effects on people. It primarily deals with creating social harmony and adjusting attitudes and behaviors to assimilate into one’s social environment. It is useful for diplomacy, empathy, and navigating social circles. It works in a similar fashion to Te, except it asks “Is this acceptable?” instead of “Does it work?”. It manifests itself in social graces, politeness and sensitivity towards others’ feelings.

If you are Ni dominant, you utilize one of these functions whenever you engage in an activity in the external world. Your extroverted judging function is also the function that is most visible to the external world. Therefore, in the rare case that you cannot determine which one you use, asking someone else may help.

Theoretically, you cannot consciously use more than one function of the same category. You can have only one of these functions in the first four functions of your type. [P]i, [J]e, [J]i, [S]e. It may be possible to use Fe and Te at the same time but it would create internal conflict because the two functions work in opposite ways.

If the descriptions are not sufficient, consider how you would act in these scenarios:

  • You are a manager and you get the impression that an employee is not performing well (Ni). You decide to confront the person.
    • Do you look at his quality of work, throughput, time sheets, or other measure of performance for evidence? (Te)
    • Do you look at his work ethics, dedication, loyalty, or whether he is trying his best? (Fe)
  • You are shopping for electronics at a retailer and cannot decide between two brands of the same item. The two items are similarly priced and provide the same functionality.
    • Do you compare the technical specifications to look for reason why one is superior to the other? Do you consider the durability and longevity of the material the item is made of or check for warranty? (Te)
    • Do you choose the one you think is aesthetically pleasing or “fits in” with your other electronics? Do you ask friends/family if they have used it before? Do you ask a person, friend or look up reviews to see what other customers thought? (Fe)
  • You receive a call from a telemarketer who tells you that you are the lucky winner of a free travel package. You have told them you are not interested but the caller insists, which gives you a hunch that it may be a scam. (Ni) You are not busy but want to end the call.
    • Do you hang up on the person? Do you ask the caller about the business model and try to discern the “catch” behind the offer? Do you research the company online or ask for legal verification of its legitimacy? Do you confront the caller about his/her tactics and ask how they got your number? (Te)
    • Do you gently state your concern to the caller? Do you check if his/her voice and speaking style “feel” sincere. Do you create an excuse for why you can’t talk at the moment? Do you empathize with the caller because he/she is just another person trying to earn a living? (Fe)

If you still don’t see a clear preference for either, you maybe very introverted or may not have had the opportunity to develop your extroverted judging function [J]e.

The next part which discusses the tertiary difference will probably help you decide if you prefer Ti or Fi for [J]i.


Some people cannot decide if they are INFP or INFJ. Both types are idealists and seem similar on a superficial level, so it is common for INFPs to mistype as INFJs and vice versa.

Reasons for Indecision

Low J or P Scores

The official MBTI score report presents a continuum between the four dichotomies.

I/E – Introversion – Extraversion

N/S – Intuition – Sensing

F/T – Feeling – Thinking

P/T – Perceiving – Judging

In addition to showing your preferences (INFP or INFJ), it displays a numeric value that indicates the strength of the preference. 100% showing definite preference, 0% showing no clear preference. This leads to the common misconception that the dichotomies are traits, meaning a person with a high F has a low T or a person with a high J has a low P. The numbers do not measure how much of a judger or a perceiver you are but measure the accuracy of the test’s results. Therefore, if you are an INFJ with low P or an INFP with low J, the accuracy of the fourth letter should not affect your type decision.

What do P and J mean?

P and J have different meanings for each type. It is difficult to explain this dichotomy without using cognitive functions (which I will introduce in the next section). But first let us dispel some of the common myths about this dichotomy:

    • Js are organized and Ps are messy
    • Js are closed minded and Ps are open minded
    • Js are planned and Ps are improvisational
    • Js work hard and Ps slack off

In most online tests, the test questions that increase the J score surround these stereotypes.INFJ and INFP are a perfect example of why these myths are false.

INFJs are Dominant Perceivers (Pi) while INFPs are Dominant Judgers (Ji).

So why is there a J in INFJ and a P in INFP?

As mentioned in the previous article, J and P are determined by the presence of an Extraverted Judging (Je) function as a dominant or auxiliary.

INFP uses Fi Ne Si Te (Ji Dominant)
INFJ uses Ni Fe Ti Se  (Pi Dominant)

The two types do not share any cognitive functions. Based on the brief descriptions here, you may be able to pinpoint which function you use more than others. The functions are arranged in descending order of strength.

Here is a brief summary of how the dominant/auxilliary functions manifest in these two types:

INFJ (Ni-dom)

INFJs are dominant Introverted Intuitives. Introverted Intuition is the least common dominant or auxiliary function so it is difficult for many people to imagine what the experience is like. As an INFJ myself, I can only give you my subjective experience of Ni and the anecdotes I have experienced. In the INFJ, Ni is complemented by Fe to create an uncommon depth of feeling and compassion so it is difficult to compartmentalize the experience into feeling and thought. They are the most intuitive type because they have an unfiltered access to unconscious content. Unlike INTJs, who share the same dominant function, the intuition of the INFJ does not need external validation which makes it appear out of nowhere and gives them a “psychic” or “mystical” appearance.


Ni searches for depth, meaning and significance in the world. It can be thought of an elastic web of insights that is constantly being refined and expanded. The goal of the function is to filter out biases and refine perception to arrive at the “one truth”. Monism, the notion that there is one truth is at the core of Ni. For this reason, it may be mistaken for Ti, especially in INTJs and INFJs with under-developed Fe. However, Ti can be conceptualized like a solid grid of principles and rules that serve as a filter function to determine if the provided data is true/valid or false/invalid. The difference here lies in the fact that Ti works similar to a mathematical function, an input is given, Ti processes the logic and returns an output. Ni, on the other hand works similar to a fine tuning radio or a camera lens that is constantly readjusted to get the right data. When it is not active in the external world, it enriches the INFJs internal world with imagination, philosophical insight, fantasy, poetic ideas and a never-ending curiosity about why things are the way they are.


Ni-Fe makes INFJs natural psychologists because it helps them model how minds work. They are not naturally introspective about their feelings but have a great deal of insight into their minds and thought processes. The psyche’s ego-defense mechanisms and self-deception are weakened by the constant filtering of Ni, therefore they can be highly sensitive and are known to have fragile egos. This obsession with truth results in the INFJ being seen as naive and innocently honest about their own motives and that of others. The auxiliary Fe absorbs the emotions and mood of the social environment. It is extremely good at interpreting facial expressions to quickly spot out insincerity or malevolent intent in other people. It also results in a natural desire to like people and be liked by them, which provides Ni with an intersting topic to study (humans). The default orientation of feeling is extroverted so INFJs constantly look for the perfectly trustworthy person to whom they can share their internal world or true selves. Feeling is usually expressed when it is experienced, otherwise it is translated into action or rationalized by Ti. As Fe users, they tend to process their feelings through self-disclosure or direct action, so they are not prone to passive aggressive behavior or emotional suppression. The INFJ does not have constant awareness of their internal feelings and reactions, so the stress they experience daily may accumulate and manifest in a somatic form in sickness or a physical feeling of malaise. This lack of awareness in mood can be seen in their facial expressions, as they do not try to (or are not good at) displaying facades. Other people may get the wrong impression that an INFJ is feeling sad or gloomy when the person actually feels neutral because the INFJ is focused in his/her internal world. Fe also provides the INFJ with a “higher purpose” to strive towards, this is usually something external such as a political/social movement, liberating the oppressed, feeding the poor. Their concern for others makes them great social leaders and humanitarians.

INFP (Fi-dom)

INFPs are natural feelers. They have a rich emotional life that they greatly prize and have a strong understanding of their inner workings and sense of self. Fi is an ever-present evaluator that places things on a spectrum of good and evil. In the moral sense, it results in strong commitment to ideas and values as well as a yearning for spirituality and religious experience. Attraction and Repulsion are emotions that are frequently experienced by INFPs, this gives them a strong appreciation of beauty in all its forms. They are naturally attracted to the beautiful and good things in life. Fi gives the INFP an internal ideal to strive towards, they constantly seek internal perfection. They have an ideal self with ideal qualities that drives them to improve themselves. Given the breadth and depth of feeling they experience, they can easily see things from others’ perspectives. This makes it difficult for INFPs to pick sides during conflicts because they can imagine themselves in the “other’s shoes”. Fi also provides them with a constant radar of their internal emotional states, as a result they have great intrapersonal intelligence and can usually deal with disappointments and unpleasant circumstances in a graceful manner.

Fi is a very complex process that is hard to define in words. Even INFPs have a difficult time explaining it because it is quite intangible and happens in the viscera instead of the head. Trust your heart above all else is the motto of the INFP. It is a very complex reasoning process that remains mysterious to neuroscientists and artificial intelligence researchers. It has to do with assigning meaning, value, worth and emotions to ideas, objects, and feelings themselves. It is very subjective and every INFP has their own individual version of the function that has been shaped by their life experiences and innate tendencies. It makes INFPs strong moralists and gives them a sense of absolute right and wrong. This process is very different from that of the INTPs because it is not concerned with creating universal ethical principles but weighing ideas by the quality of their subjective feeling tones. Fi deals with abstract ideals so it is never satisfied with particular “imperfect” instances in the real world. INFPs are just as likely to judge themselves as they judge others. This may result in unrealistic grandiosity or chronic low self-esteem depending on the distance between their ideal self and actual self. Emotions are experienced as states of the self and can be internalized into the person’s self-image. They believe feelings are at their essence so they are more likely to think “I am mad” instead of “I have anger I need to deal with”.

Fi and Ne work together to give INFPs a sense of optimism and a fresh enthusiasm for life. For INFPs, the world is created as much as it is perceived, and as a result they come across as dreamy and having their “head in the clouds”. This quality gives them unusual strength to persevere through difficult circumstances and “bounce back” from life’s disappointments. Their life force is reinforced by a curiosity and enthusiasm for life that is constantly renewed by their imagination. Fi-Ne makes them extremely creative and good with words. In combination, these two functions work to help them find just the right word or the right chord in their creative pursuits. It also makes them gifted fiction writers due to their rich imagination that is fueled by personal values. They have an emotional life that seeks expression in some form of creative outlet, and some INFPs recover from life-long depression by engaging in creative activities for the first time. Truth for the INFP is felt instead of intellectualized, therefore they are likely to practice spirituality that allows for free-exploration and feeling connections. They can be inflexible when it comes to their values and strongly held beliefs because there is usually a strong emotional charge behind their values. INFPs make great counselors because they have the keen ability to see potential in others using their Fi-Ne. But it also makes them naive and can lead to unrealistic idealism. This can be harmful to the INFPs because they have a tendency to idealize new people they meet by assigning positive qualities that person may not necessarily possess. It can also blind them from the negative aspects of reality, which may result in a dissapointment with the “real world” when life circumstances demand a reality check on “cold truths”. Fi-Ne gives INFPs a unique ability to detect sincerity and honesty in others. This gift is related to their ability to detect subtle variations in intonation and pitch when others’ voices. Along with their natural aptitude for language, they can make excellent speech therapists, linguists, writers and translators. Ne gives them an advantage in almost any academic field they pursue due to their capacity to easily grasp ideas and thus can be found in a wide variety of careers.