How would you describe the core similarities and differences between Si and Ni?
The answer depends a lot on how deep you want to get into it. The simple answer is that Si prefers concrete experiential information, such as data, experience, procedure, tradition, and habit. Ni, on the other hand, prefers less concrete information, particularly trends, patterns, principles, concepts, symbols, and themes.
If you want to go a level deeper as to why this is the case, and exactly how these functions work, it’s a bit more complicated. Both are perceiving functions, meaning their fundamental task is to connect new information to the body of existing knowledge. Si creates these connections directly, soldering them into the framework like they were always there. This is a fast process, allowing a large quantity of information to be digested. This is why Si users tend to have prodigious and unparalleled recall, particularly of facts, events, and experiences. As an introverted function, Si is chiefly autobiographical and subjective, so Si users are preferential towards personal experience and tend to prefer singular interpretations that will play a significant role in defining them.
Intuition, unlike sensing, connects new information to existing knowledge through an intermediate switch. This switch is important, as it represents the connection between two pieces of information. It can be shut off or reassigned, which provides flexibility, and it can also itself be connected to other switches through additional switches. This pathway allows for complex, nonlinear, runaway abstraction of information. As a result, intuitive dominants, particularly Ni dominants, will be plagued with circular, web-like, ineffable ideas that are hard to justify but appear manifestly true to the user. Intuition can manifest this way no matter where it is in the stack, so this is by no means diagnostic of any particular type, but pay attention to whether this trait is the dominant force in a person’s personality. Like Si, Ni is subjective and autobiographical, preferring a singular interpretation that may play a significant role in defining the user.
Dominant users of either function will tend to present with strong long term memory, both for facts and for events. Both will tend to be reticent, sensitive, introspective, and difficult to read. Though this is a generalization, a good rule of thumb is that Si users will tend to spend much of their lives searching for a feeling - a sense of calmness, or happiness, or security that feels tied to their identity. Ni users, again I’m generalizing, also tend to be on a similar quest, but are searching for truth instead. This truth will be difficult to explain and highly personal, much like the feeling sought by Si users. These quests exist in all people, regardless of where these functions appear in the stack, but are most pronounced in dominant users of these functions, namely the I-Js.
It is important not to confuse these functions with judging functions, which is an easy mistake to make. Fi users will also tend to search for meaning and an ineffable emotion in their lives, and Ti users will also tend to search for truth. However, Fi and Ti are reductive - their goal is to reduce information, form conclusions, and simplify the inherent complexity of experience. An Fi user will wish to distill a specific quality from the noise of other experiences, while a Ti user will wish to distill a specific truth from the noise of other data. Perceiving functions, on the other hand, are additive. Their goal is to seek new information and provide clarity through corroboration rather than analysis. Thus, an Si user will seek to be surrounded by that ineffable feeling, rather than distilling it from the noise. They will pay attention to every feeling, which is why the one they’re searching for has to surround them entirely. The same is true for the truth sought by Ni users. They will pay attention to every realization, every principle, every pattern and connection. Thus, they want to be surrounded by that ineffable personal truth, their lives saturated with it.
Distinguishing functions can be difficult until we get an intuitive sense for them and how they work. It takes years of practice and even the best of us can be blindsided sometimes. So please feel free to reach out for help any time you want it. My inbox is always open, PMs and all. Hope this helped :)
