I thought that was rather fascinating, seeing as Si is also so strongly associated with memory. It made me wonder if Si is like trying to remember and make sense of what has happened, and in similar terms, Ni is like trying to reveal and make sense of what will happen.
I like this...mainly because Pi is really about one's impressions of things, whereas Pe is about external possibilities. Of course, this adds Je into it, because you're describing some reasoning in there too by "making sense" of things (being a Ji-dom, it's hard to fathom NOT thinking rationally first & foremost). Si-dom are often described as enjoying reviewing what they know, which is really just going over it, not arranging it in any order according to logic or value.
Similar to how Je judges using external criteria & seeks to create & establish viable systems, Pe creates & searches for what is possible in reality; whereas Pi explores internal impressions & interpretations, making it less visible, much as Ji is about creating & perfecting systems in concept & also less visible in action. For the P types though, things just pop up & are followed, which is easiest to imagine when you think of it in terms of Se-doms exploring literal sensory experiences. J types use lines of reason to explore things, because they're trying to make sense, not just experience or become aware of.
Jung also describes Ni as pursuing the inner images much as the Ne type runs after external possibilities. Again, that arrangement into categories is not there (that's where Je/Ji comes in).
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This discussion vaguely connects to a breakdown of Jung's wording in a Ni description I was mentally doing the other day. I was putting the same thought in different words to clarify it to myself (this is a typical exercise of a fun filled day with moi). It provides a nice comparison/contrast of Si/Ni which I think sheds light on what Pi is.
Whereas introverted sensation is mainly confined to the perception of particular innervation phenomena by way of the unconscious, and does not go beyond them, intuition represses this side of the subjective factor and perceives the image which has really occasioned the innervation.
My simplification of this using less dense language:
Whereas introverted sensation is mainly focused on the perception of particular,
stimulating & impressive facts, occurrences, or circumstances via the unconscious, and does not go beyond them, intuition represses this side and instead perceives
the archaic mental image which has actually caused the
stimulation/impression.
And my long-winded way of interpreting this:
The Si type perceives their subjective impression of tangible experience & facts & even people ("the object"). Their impression is still of the literal objects, but they prefer to focus on their own interpretive view of them. This is why Si is compared to impressionistic art; it's reality through the highly idiosyncratic view of the individual. It is colored by the unconscious, which determines what details the individual responds to & focuses on. Ni ignores all this in favor of going directly to the "image" from the unconscious that stirs the impression of the object. The image amounts to a symbol representing the essence of that object. This is why the Ni type experiences their iNtuitions as "objective", because it's not about their personal impression (as it is with the Si type), but an image representing a universal, core "truth" about the object arising from the collective unconscious. However, the individual is still interpreting this image & its "truth", and that's when it becomes highly subjective (as does every introvert's experience of the collective unconscious).
