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The ISTJ Type Description 1.0 (based on Jung's model)


New member
Jun 28, 2021
Instinctual Variant
This write-up attempts to provide a general simulation of what the ISTJ type is really like, based on the Jungian model of cognitive functions.

I am not the first one to discover this model and in fact, people had discussed this alternative model in the last decade. For an example of such discussions, see this 2014 post: Jung and the attitude of the auxiliary

I am not a follower of any group or any particular branch of typology theories. What I’m doing, at this point, is exploring the existing theories and coming up with my own analyses. I like to “think out aloud” and exchange ideas with people.

Although some previous discussions have been done in the formulation of this model, it seems that none of them have come up with general type descriptions based on the Jungian model. Therefore, my attempt is to fill this gap by providing an objective and abstract description of each type, based on their cognitive function arrangement.

Unless otherwise cited/noted, all represent the author’s original thinking.

There are 16 types and this is the first one in the series. There is no guarantee that I’ll finish writing about all the types. As a chronic dreamer, my interest can easily drift away toward something else (and may not come back, who knows).

Feel free to disagree. Take everything with grains of salt.

The ISTJ general model (simulation, version 1.0) – is not based on specific individuals but simply a very general sketch of what the real ISTJ is like. TiSiNeFe – is the Jungian model of the ISTJ’s cognitive functions.

The ISTJ - introverted thinker and judger (IT) who uses internal sensation to collect data (ST).

As a Ti dom, the ISTJ is primarily an introverted thinker attentive to building concepts, constructing theories, and making analyses based on subjective logical reasoning. The ISTJ can be a good theorist and abstract thinker due to Ti’s analytical power. Because Ti naturally carries with it the ability to make abstractions, the ISTJ can oftentimes be mistaken for Ns. To the ISTJ, what can convince them best must have a tight, consistent, and thorough logical framework and they might value the logical consistency above anything else.

They tend not to accept facts as they are without questioning, but rather, they use facts in their theory construction and in the revisions of their theories. They may have an intense interest in figuring out how things work and seeking to understand the rationale behind everything. They are principle-oriented people who may also care about real-world applications of theories.

The ISTJ may be messy when it comes to managing their living space (e.g., having organized chaos at home) but their internal logical framework is usually neat and structured. They can be perfectionistic and demanding when it comes to building concepts, finding principles, and doing logical reasoning.

Si is what the ISTJ uses in gathering information. As mentioned in my other post, Si is about subjective perceptions. Si information is all-encompassing, including (day)dreams, past experiences, subjective perceptions, and personal perspectives of everything. As such, the ISTJ often enjoys the wide range of information their Si brings to them.

Because Si is more in touch with reality than Ni, to an interested observer, the ISTJ’s theory may be relatively easier to understand than the INTJ’s. If the ISTJ is a practical philosopher, the INTJ would be a futuristic philosopher.

I tend to be skeptical toward the archetypical ISTJ in the traditional MBTI description. The Jungian ISTJ cognitive function arrangement suggests that they are more original and independent thinkers (due to dominant Ti) than defenders, guardians, followers of tradition, or boring and close-minded people. The real ISTJ may be completely different from the stereotype. They can be imaginative, flexible, and innovative when needed, and they can also be stable, loyal, and old-fashioned. If the ISTJ’s Ne is conscious, it means that they will be more comfortable contemplating possibilities and discussing alternative scenarios.

Does the ISTJ value tradition? – the most likely answer would be: it depends. As Ti doms, the ISTJ tends to question a tradition first, and they might follow a tradition only if it makes sense to them. They are less likely to obey traditions simply because. The same applies to their general attitudes toward authority.

The Jungian model may help clear many misunderstandings regarding sensing types. I guess that the bias of “sensors bad” can be largely attributed to the stereotypical descriptions of high Si users (all the way back to the MBTI official type descriptions). No one wants to be seen as close-minded, authoritarian, rigid, and boring, and few people understand what kind of people the ISTJs truly are.

What does the real ISTJ do all the time? – in a word, constructing an internal theoretical framework based on experiences, subjective perceptions, and personal perspectives (overall, what is known/real to them).

I would hypothesize that there are two main subtypes of ISTJs in reality:
1) the theorists and abstract thinkers (Ti-centric) and
2) those who fit more into the traditional description (defenders, Si-centric); of course,
3) there might be a third subtype, a minority, with conscious Ne – inventors.
Sounds familiar? Yes, these are similar to the people who constantly test as INTPs in online tests.

How should the stereotype be viewed? While it is not completely false, it can be said as only partially true. While it may describe some ISTJs well, it has failed to capture the others. A generalization is considered faulty when it only gets the characteristics of part of the population.

As for the INTP (NiTi) in Jung’s model, I might write about them later, but they seem to be very different from what the popular belief suggests. Perhaps over 90% of the INTPs you have met online, are of other types, but it’s OK.

Last note: I think that Karl Marx might be an ISTJ.

I hope you find this article helpful. Thanks for reading. Let me know your thoughts by leaving a comment.