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According to Daryl Sharp

A form of psychic activity, or manifestation of libido, that remains the same in principle under varying conditions. Jung’s model of typology distinguishes four psychological functions: thinking, feeling, sensation and intuition.

Sensation establishes what is actually present, thinking enables us to recognize its meaning, feeling tells us its value, and intuition points to possibilities as to whence it came and whither it is going in a given situation.

[“A Psychological Theory of Types,” CW 6, par. 958.]

Though all the functions exist in every psyche, one function is invariably more consciously developed than the others, giving rise to a one-sidedness that often leads to neurosis.

Casually Explained

From PDB discussion boards. Original thread

The more [a man] identifies with one function, the more he invests it with libido, and the more he withdraws libido
from the other functions. They can tolerate being deprived of libido for even quite long periods, but in the end they will react. Being drained of libido, they gradually sink below the threshold of consciousness, lose their associative connection with it, and finally lapse into the unconscious. This is a regressive development, a reversion to the infantile and finally to the archaic level. . . . [which] brings about a dissociation of the personality.

[The Type Problem in Aesthetics,” ibid., pars. 502f.]

This is for all the people who understand the cognitive stack but did not understand the meaning of the cognitive functions yet, i created an easier system for didatic purposes:
- Lets divide a function in three dichotomies:

  • Perceiving vs Judging
  • Experiential vs Mental
  • Objective vs Subjective


  • Perceiving: Gathering data
  • Judging: Creating conclusions:


  • Experiential: Everything that can be experienced by you
  • Mental: everything that is abstract.


  • Objective: External, not unique from the self
  • Subjective: Internal, unique from the self.


Si: Perceiving, experiential, subjective -> Your inner knowledge perceived in your own unique way (experience)

Se: Perceiving, experiential, objective -> The multiple sensory informations that can be perceived to all people in the same way (empirical data)

Ni: Perceiving, mental, subjective -> your inner intuition/creativity that is perceived in your own way (heuristics)

Ne: perceiving, mental, objective -> the abstract info such as creativity where the ideas can be "gathered" by all the people (brainstorming)

Fi: Judging, experiential, subjective -> concluding by your inner emotions (internal values)

Fe: judging, experiential, objective -> concluding by multiple other people emotions (external values)

Ti: Judging, mental, subjective -> concluding by your logical facts in your unique way (rationalism)

Te: Judging, mental, objective -> concluding by your logical facts in an external way (empiricism)

"But isn't the feeling functions mental?" No, because emotions are experienced by chemical reactions / hormones inside your brain, so no "oh my emotions are in my heart" BS :)

And If you are confused by the J/P dichotomy i created (lol), keep in mind that in MBTI, If the *extroverted* function in the *Dominant/Auxiliar stack* and It is a *perceiving function* -> It will be typed as a P


  • TiNe -> INTP
  • NiTe -> INTJ

Descriptions of Each Function

From PDB discussion boards. Original thread

Perceiving vs Judging Functions (What's the Difference?)

The first thing one need to understand before learning about the cognitive functions is the difference between perceiving and judging functions. Perceiving functions (usually denoted by S or N with a small script e or i, meaning extroverted or introverted: Se, Si, Ne, Ni) are just that- how you perceive (i.e. what you notice) about the world and what you prefer to pay attention to. Note: you aren't making any judgments about what you take in, you are just taking in the information with perceiving functions. With judging functions (usually denoted by T or F: Te, Ti, Fe, Fi), you are making a judgment on information that you take in (in the case of Te/Ti "is this valid or invalid"; in the case of Fe/Fi "is this right or wrong"/"is this good or bad"/"do I value this or not"). You usually will hear things like, "he's a dominant judger" or "she's a dominant perceiver" and usually that is referring to your first or dominant function in your cognitive stack. How can you tell if you're a dominant perceiver or judger by just looking at your letters? Easy:

After a typical MBTI test, you will receive 4 letters that end in either a xxxP or xxxJ. For extroverts (ExxP or ExxJ), it's pretty straightforward: if there is a P at the end, you are a dominant perceiver. If there is a J at the end you are a dominant judger. For introverts (IxxP, IxxJ) it's a little bit more complicated- you want to flip the logic- If you're an introvert and have a P at the end (IxxP) then you are a dominant judger; if you have a J at then end, then you are then you are a dominant perceiver.

Dominant perceivers (notice your first letter- I or E, determines your dominant subscript):

ESFP, ESTP (dominant Se); ISTJ, ISFJ (dominant Si); ENFP, ENTP (dominant Ne); INTJ, INFJ (dominant Ni)

Dominant judgers (again your first letter determines the subscript of your dominant function):

ENTJ, ESTJ (dominant Te); ISTP, INTP (dominant Ti); ENFJ, ESFJ (dominant Fe), INFP, ISFP (dominant Fi).

Another pattern we can notice/appreciate is the for perceivers you take the first two letters of their MBTI to get their dominant function (example, [ES]FP gives you Se and [IN]TJ give yous Ni) while for judgers we take their first and third letter to get their dominant functions (example: [E]N[T]J gives you Te and [I]N[F]P gives you Fi). It's nice how it all comes together in a nice little package like that.

What do all these letters mean?! (Explaining the Cognitive Functions)

As I mentioned earlier, perceiving functions focus on taking new information in. While judging functions makes a judgement on new information. The extrovert (e) and introverted (i) subscripts refer to whether you prefer to focus more on the external world (e) or your internal self (i).

Important Note about extrovered/external vs introverted/internal functions (aka objective vs subjective functions):

Sometimes extroverted functions get a bad rep for being "flighty" or "too focused on simplifying things." I want to note that there is an extreme amount information in the external/physical world. When focusing on yourself and your internal thoughts, experiences, feelings, and sensations, you are dealing with a significantly less amount information, so there is room to dive deep. The experiences, thoughts, and feelings of one person who has lived to 100 will be just a drop in comparison to all physical and abstract data regarding Earth/our environment. It's one of the reasons humans have accepted that a singular person can't know everything there is to know about the world in one lifetime- it's not practical or nor feasible, thus people with dominant external functions tend to either simplify things or focus on stimuli within the external world for a brief amount of time. Please keep this in mind while I explain the functions.

Let's start with the perceiving functions first:

Sensing functions (S) tend to focus directly on physical stimuli

Se (extroverted sensing) - what you notice about the external world using your 5 traditional senses- touch, sight, taste, hear, and smell. People with dominant Se tend to highly attuned with the external environment and can react to external environmental stimuli very well. Se tends to be very present focused- "what am I sensing or noticing about the environment/reality right now."

Si (introverted sending) - what you physically notice about yourself internally. Si seems to be linked to kinesthetic sense and sensations to how the environment makes you feel (ex. Do I feel hot or cold? Am I sleepy? Hungry?) Si users tend to be highly attuned to their physical internal senses and understand how they are physically feeling in the moment.

We often hear that Si is related to the past, structure, and memories. This is because Si also keeps track of how you have done things in the past and, more importantly, how those things physically made you feel. Emotions and internal physical sensations are often linked, and Si-users tend to be more attuned than the average person to these physical sensations as well as keeps track of them over time. People with dominant Si tend to (but of course not always) eat the same foods that they liked/make them feel pleasant, shower at the same time they know makes them feel the best afterward, and so on. You can also think of it as dominant Si as a bit of a record keeper that keeps track of how physical stimuli has makes them feel now and has made them feel in the past.

Intuitive functions (N) tend to make abstract connections between physical stimuli

Ne (extroverted intuition) - what abstract connections you notice between two or more pieces of physical information in the external world. An example would be looking at a blue towel and thinking of the beach, because you have associated the color blue with the ocean. Another example would be saying a belt looks like a snake because they are similar in size and shape. Ne tends to associate meaning and abstract connections to physical stimuli.

Ni (introverted intuition) - your own personal underlying abstract statements that attempt to explain and predict the physical world. Ni is where you look for abstract "truths" or underlying cause-and-effect relationships (or simply just, underlying relationships) between multiple physical stimuli. "How are all of these things related?" and "What will happen once these physical stimuli are manipulated?" are what Ni attempts to answer. Ni is your own personal synthesized statements attempting to capture your observations and answer those questions. Similar to Si, Ni is also like a record keeper, that keeps track of your synthesized statements/answers so that you can compare new information to them in the future.

Side note: Determining Se vs. Ne is like, “Am I focusing on what’s actually in front of me (i.e. a tree is a tree/that towel is blue) or do I associate meaning with it and try to form an abstract connection with/between the item and something else (trees imply Christmas, blue implies peace, serenity, ocean etc).

Next let's take a look at the judging functions. Judging functions make a judgement whether new information, typically a conclusion, statement, or action, is valid or invalid (Te or Ti) OR right or wrong (Fe or Fi). These judgements are made based on an external or internal set of standards/criteria, which are largely influenced by the highest-stack perceiving function:

Thinking functions (T) determine whether a statement is or action valid or invalid.

Te (extroverted thinking): determines whether information is valid or invalid based on whether it matches the heuristics you use to understand the external world. Heuristics are very efficient in nature, as they are used primarily to make quick decisions. Because heuristics are directly based primarily on patterns/repeated information in external world/environment, if there are no patterns or organization in the external world then Te becomes useless. Hence, people with high Te prefer their environment to be organized and structured to some extent. So, overall Te uses heuristics matching as a basis, uses generalizations, and is more similar to inductive reasoning.

Ti (extroverted thinking): determines if something is valid or invalid/true or false based on whether it is consistent with previous information you have gathered/determined to be valid. It is based on your own personal conclusions/principles/axioms you have previously determined to be true, rather than a pattern/heuristic you have noticed in the external world that will likely lead you to a true answer (which would be Te). It looks for logical consistency and is similar to deductive reasoning.

Feeling functions (F) determine whether something is good or bad/or right or wrong

Fe (extroverted feeling) - determines whether something is good or bad/right or wrong based on social values your external group or community has agreed on. Fe-doms are hyper aware of group dynamics, social values, and rules of their culture/group and will judge whether something is right or wrong primarily based on whether the decision aligns with those values. Think etiquette, being willing to be hyper aware of how others in the room feel and making decisions based on that, etc.

Fi (introverted feeling) - determines whether something is good or bad (or right or wrong) based on your own personal set of values. These values are developed over time based on your observations and experiences.

The last thing I'll say about the judging functions are that Fe/Te (extroverted judgers) are more flexible in nature because they are based on external patterns/values. Whereas Fi/Ti (introverted judgers) are more rigid and stubborn in nature because they are based on internal principles/values.

Also note that, Fe =/= empathy and compassion, Fi =/= selfish, Ti =/= smart, and Te =/= efficiency (although it does tend to be related to efficiency). These are all stereotypes and should not be used when typing.

Another misconception I see is about Ni, Ni is not symbols or a goal, although Ni users can of course have them (but so can every MBTI type). It’s more about trying to find underlying relationships between things in the external environment (i.e. "How are all of these things related? What is something that connects them all?").

I hope this is helpful and clear. I'd be happy to expand upon anything, answer questions, or even discuss with people who feel something is inaccurate!

From PDB Discussion Boards.

Sensing, Intuition, and the "Object"

Se: THE OBJECT, how it appears, how can we directly engage with the physical existence of the information through senses (Touch, smell, sight, taste, hear).

  • Purpose: Se engages directly with the object so that we can be adept and agile in the real world. Reality in general needs physical exertion and effort so you can be mindful and aware of your environment.

Ne : The concept of the object. How it exist ideally and conceptually through our minds. It looks at real time environment but instead of gathering sensory, tangible information it looks at the metaphysical elements such as : being, identity and change, space and time, causality, necessity and possibility. It includes questions about the nature of consciousness and the relationship between mind and matter.

  • Purpose: Ne purposely innovates for the sake of increasing your chances to react to changes and discover new opportunities since the world is constantly evolving.

Si: Personalised attachment to the object. How it reminds us of a life that has been imprinted in the object. How the object is part of someone's life. It is determined through the personal sense of how the object stimulates the senses of a memory or a solid perception from past precedent.

  • Purpose: Si helps us find our place in the world. By determining the segmentation of what makes reality can we establish bonds and attachments to develop or experience in particular locations and environments. The nomads have to settle somehow and know their roles in the vast world so that they can create LIFE.

Ni: The deep and personalised interpretation of the object which meets the concluding end. It is ability to perceive or know things without conscious reasoning. A sense of anticipating and assuming the probable outcome by understanding the motivation of the existence of the object. It upholds the depth of its archetype that is extracted and formed in an organized manner to determine the linear scheme of the object.

  • Purpose: Ni helps us understand reality in a perspicacious digestible manner. Through our mind, we can conceptually conclude any situations we experience or soon to experience which helps narrow down options or single out the right outcome.

Original thread

Sensing and Intuition are Oppsite Ends of the Perception Scale

One thing that helps is to imagine an axis, or a spectrum. Similar to how black and white are opposite ends of the color spectrum, sensing and intuition are opposite ends of the perception scale. You start out with sensing, which is concrete, and you get more vague and abstract until you reach intuition. Now instead of these areas on the spectrum simply representing “now” or the “future” think of them simply as lenses in which you perceive the world.

Ni, is an abstract lense oriented towards the internal world. What also helps is to look at how it interacts with Se, as it is on the same axis as Ni. So an Ni user perceives the outer world with Se, directly perceiving the concrete aspects of external reality. As they internalize the info perceived with se, they then view the internalized data through an abstract lense. This then leads to conceptual models that are then stored and used for the future.

A lot of people say that Si is the function that deals with past information, but Ni does the same exact thing. It’s just that the information being brought up into the mind is conceptual information, which is a lot harder to explain than sensory info. This gives Ni the appearance of being mysterious or future oriented when really, it just has a lot of abstract info stored.


One thing to keep in mind is that the apparent behaviors of Ni-Se can be the same of those associated with Ne-Si. It’s just that they produce those behaviors in different ways.

Imagine a guy who has to arrive at work by 8:30am. He has a new job at a huge law firm. He’s driving up to an intersection, and he sees that the time is 8:26. He sees a few cars recklessly speed up into the left lane, and some into the other lane. Half of the cars turn right, and the other half turn left. Most of the cars that turned left are really nice looking, expensive cars. The man approaches the intersection and he has no idea where to turn, he forgot the directions to the law firm. He’s uncertain for a few moments, but he randomly gets a strong urge to turn left at the intersection.

It seems that his Ni mysteriously provided some sort of insight, but it was really Se that started the process. If you look at the previous paragraph, you notice that there are a few particular details that the man saw. During the time he was approaching the intersection, he had abstractions that were formed once these details were taken in. He associates Law Firm, with wealth and status. The time 8:26 is associated with being late for work. Cars recklessly turning into different lanes are associated with people being late for work. Nice looking expensive cars are associated with people who are wealthy and have a high paying job.

All of these associations are subconsciously synthesized and produce the insight that turning left is the right direction to the law firm. The person concluded that it was the right way to go because of how the details in his immediate environment connected to already existing abstractions in his mind. Expensive cars speeding and turning left are associated with wealthy people who are late to work. He then realizes that these people are probably people who work at the same law firm as him, so his best bet is to turn left with them.

This is an example of how an Ni dom might figure out problems in the external world. They have some sort of goal in mind, and they need to reach this goal somehow. While they may not know the details that can help them reach the goal, they do have a large web of internal concepts and abstractions. They can then perceive external details that may be related to their goal, and they find those relations by internally perceiving underlying abstractions associated with those immediate details.

To simplify it a bit, Se works with immediate details, and Ni works with internal abstractions, or concepts. Se provides the cars, roads, and lanes. Ni then provides the concepts associated with these details. An Ne dom works with immediate ideas and possibilities, while Si provides internal details. Ne sees multiple ideas for getting to work as they look at the environment, and Si provides relevant details that help single out the best idea. Both combinations are capable of producing a gut feeling to turn left at the intersection, it’s just that they have different ways of getting there.(I’m still struggling to grasp Ne-Si, so that may not be the best explanation).

Original thread

Si vs Ni: Details and the Big Picture

Both Si and Ni focus on accumulated impressions of the outside data. However, while Si focuses on impressions themselves, Ni focuses on the conclusions it can derive from these impressions. That’s why Si is more detail focused – because it retains impressions more vividly. And Ni is less detail oriented and more big picture – after conclusions are derived from impressions, the impressions themselves lose value.

Ni is gonna look at it as a whole; not paying attention to specifics. It's aphoristic and holistic. Whereas Si is gonna be concrete with impressions, retaining the events in their fullest form (or closely to their fullest), paying attention to when they happened, where; the specific occurrence/place and all other relevant details specific to the Si user's subjective experience of the situation.

The details truly do lose value to Ni once concrete data has been synthesized; all that is left is a singular essence/general idea/general theme.

Original thread

Both are organising functions.

  • N functions deal with abstract patterns and S functions deal with concrete facts and things.
  • Ni organises abstract patterns, narrowing down to the ideal patterns for the individual to use/refer to to survive and thrive with;
  • Si organises concrete data, creating physical order and narrowing down to the ideal first hand experiences and facts for the individual to use/refer to to survive and thrive.

It should be noted that Perceiving functions (such as these) are not conscious mechanisms, but unconscious ones which reveal their findings to the user automatically as known information. In the dominant position these are used to fend off the chaos of the world: the chaotic enslaught of the sensory world for Ni and the chaotic enslaught of abstract meanings for Si, but as with all dominant functions, the user clings to this behaviour compulsively. In the inferior position the user neglects the creation of order in those facets (N or S) which they view as controlling and limiting their lives. At two or three the user utilises the function relatively healthily (depending on their general maturity: more mature = more healthy), and the functions do not play a greatly defining role in their lives compared to their Dom/Inf dichotomy.

Original thread

Explaining Ni vs Si without the Term Future and Past

Both of them are introverted perceiving functions.

Ni looks for abstract patterns by storing data about abstract relationships and implications. It has a tendency to "detach" concrete details from observations to identify the overall pattern. It uses these patterns and relationships to try and find different perspectives to look at an idea from, to ultimately realize the core meaning of that idea or concept to visualize future outcomes.

Si looks for concrete patterns by comparing and contrasting concrete details in the present with those in the past. This enables it to quickly recognize concrete detail discrepancies and identify familiar environments and procedures. It uses these familiar details as a template to approach new situations to ultimately create stability in the Si-user's environment and life.

Original thread

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