ISTP vs. ISFP: 5 Differences

ISTP vs. ISFP is a common typing dilemma, in spite of these two personality types have completely different dominant functions. We’ve written other articles in the past comparing Ti and Fi, which will likely seem similar to this article, since that is ultimately what’s determining the differences between the ISTP and ISFP. Specifically, if you check out INTP vs INFP: 7 Differences, you’ll probably notice that that article hit similar beats. However, we tried to make this article as specific to these two personality types as we could manage, and of course, we always try to write new content, based on our updated knowledge of the personality types. Anyways, let’s go ahead and start discussing the differences between ISTPs and ISFPs.

Beware of Bias

There is a general bias towards thinkers, because people get this idea in their heads that only thinkers can be intelligent. That’s not true. ISFPs can be just as smart as ISTPs, and ISTPs can be dumb. The thinking dichotomy has nothing to do with innate intelligence. Oftentimes, male ISFPs especially mistype as ISTPs because men are often encouraged suppress their emotions. If you’re the one stuck between these two types, try to evaluate yourself honestly to determine which personality you fit the best.

ISTP vs. ISFP: Cognitive Functions

As mentioned earlier, the ISTP and ISFP have different dominant functions, which also means they have different inferior functions. ISTPs have dominant Introverted Thinking (Ti) and inferior Extraverted Feeling (Fe), while ISFPs have dominant Introverted Feeling (Fi) and inferior Extraverted Thinking (Te). However, these two types do share one cognitive function pair. Both have auxiliary Extraverted Sensing (Se) and tertiary Introverted Intuition (Ni).

So, in summary, the ISTP and ISFP cognitive function stacks are as follows:
ISTP = Ti-Se-Ni-Fe
ISFP = Fi-Se-Ni-Te

ISTP vs. ISFP: 5 Differences

Bear in mind, that in this article I’m discussing ISTP vs. ISFP tendencies, not absolutes. Every individual is unique, and we all have learned behaviors gained from our personal life experiences. As a result, people rarely fit their personality type description 100%. Focus on natural, default leanings, and try to rationally determine which personality type fits best.

1. ISTP’s devalue their emotions, while ISFPs assume their validity

ISTPs are thinking dominants, which subsequently means that they have an inferior feeling function. While this doesn’t mean that they don’t have emotions, or that they don’t feel emotions, it does mean that ISTPs devalue (or discredit) their emotions. Essentially, they see their emotions as an impediment, or something that is getting in the way. Jung describes thinking dominants as “knowing their feelings very well” but denying “them any validity” and declaring that “they have no influence over him.” Essentially thinking dominant, especially very imbalanced ones, will reject the idea that emotions are affecting them or that emotions matter. It will be important to them to appear unemotional, and therefore, objective.

ISFPs, on the other hand, start from the position that their emotions are an integral part of who they are. As Fi dominants, ISFPs identify with their emotions, including them as part of their self-image. Therefore, they instinctively assume their validity. This doesn’t mean that ISFPs can’t analyze their feelings, and recognize if/when they’re being irrational. (For the record, everyone one, thinker or feeler, is equally capable of being irrational.) But, ISFPs start from the place that their emotions are valid and valuable. If they have an emotional reaction that’s unjustified, however, they can recognize this, talk themselves down, and reprogram their emotions. The point is that ISFPs assume validity and work toward invalidating, whereas ISTPs will assume their emotions are not valid and will look for logical explanation to validate them.

2. ISTPs are focused on autonomy, while ISFPs are focused on individuality

These words probably seem very similar, and they do have similar themes. After all, both ISTPs and ISFPs are introverted judging dominants, which give both types a strong focus on self. However, ISTPs on average tend to prioritize their autonomy, as a result of inferior Fe. They can be resistant to forming connections, and anything that resembles relying on others. This can also surface as actively avoiding vulnerability. ISFPs have a slightly different focus, although autonomy may still be very important to them, especially since there are basic survival needs that often require you to self-sufficient. However, ISFPs prefer to focus on defining who they are an individual, which surfaces as self-expression. They’ll want to showcase what makes them unique, and different, essentially personalize themselves.

3. ISTPs approach social interactions impersonally, while ISFPs personalize their interactions

When in touch with their Fe, ISTPs will strive to be socially acceptable and to connect with others. In other words, to do this, they approach people in an analytical way. Many ISTPs will focus on general trends for human behavior and societal norms, using these as a template for their interactions. Essentially, they work within the social system. While many types hate small talk, ISTPs may utilize it and see the validity, even if they’re not good at it. Small talk will be the socially acceptable gateway to deeper discussions.

On the other hand, ISFPs focus on what makes people distinct and unique. While ISFPs may not open up easily, they usually desire deep, intimate connections with others. Therefore, ISFPs will strive to relate to each person on an individual level. They typically have a distaste for small talk, because it’s too shallow and impersonal. Instead, ISFPs will look for shortcuts to more interesting subjects or things that will allow them to connect with the person they’re speaking to.

4. ISTPs struggle to share their ideas in a socially acceptable way, while ISFPs struggle to find concrete ways to realize their dreams

This is inferior Fe versus inferior Te. Basically, ISTPs believe that logic and truth should reign supreme. It shouldn’t have to be watered down so that others will accept it. In addition, they shouldn’t need to market any of their ideas, or earn anyone’s favor in order to be successful. If it’s good, it should succeed. Ultimately, these types hate the idea of adjusting any of their products, ideas, or logic for the sake of making it more acceptable to others.

On the other hand, ISFPs have a strong sense of identity centered around their values. They desire to remain true to themselves and true to their values. As such, they seek out ways to fully realize their dreams and ideals. It can be very difficult for them to find concrete, or pragmatic, ways to do this, without feeling like they’re sacrificing a part of themselves in some way. Ultimately, ISFPs hate the idea of sacrificing dreams for the sake of being successful.

5. ISTPs categorize by how they think things fit together while ISFPs categorize by their preferences

This point highlights how ISTPs and ISFPs have fundamentally different viewpoints on categorization. While ISTPs generally will use categorization as a means to fit things together cohesively in their mind, ISFPs will primarily use categorization to elevate or deprioritize things based on their personal value of it.

So, while an ISTP may not have very strong opinions on what their ‘likes and dislikes’ are; they will have very strong opinions about whether what they hear people, proposing as logical, makes sense to them. They will focus their judgements on whether or not things make sense rather than whether they like it or not. That’s why it’s fairly common for ISTPs to not have clearly defined preferences such as favorites. (Favorites are really just a means of categorizing things based on how they make you feel.) Some ISTPs tag something as a “favorite” simply because they’ve been asked the question so many times that they need a convenient answer to give. (In other words, it’s either not really a favorite, or they never would have identified it as a favorite without outside prompting.)

ISFPs will be more focused on whether or not something aligns with their preferences or not. They are usually more able to produce clearly defined favorites, and will generally be more opinionated about such things. They will be less concerned with whether what someone is saying fits together completely logically or not (within reason, of course). ISFPs may not be quite as bothered when they can’t fully make sense of something, as long as they are not being forced into something that they don’t like. (The Te style of thinking that says “as long as it works” or “as long as I get what I want out of it” will prevail more.) Therefore, one might say that ISFPs have a better idea of what they want and what they like, while ISTPs may have a better idea of what they don’t want or don’t like.