Recently I have been studying the various ways that Sensors and iNtuitives differ in their experience of reality. It is commonly thought (from what I've read on these forums) that Sensors experience reality "as it is" (for example, watching your feet as you walk), while iNtuitives add something to their experiences unique to themselves (for example, imagining that your feet are a giant's feet trampling over humans that are in actuality just ants on the sidewalk).
But what really differentiates the Sensor from the iNtuitive is not that the iNtuitive embellishes reality, but that they embellish it in different ways.
The Sensor embellishes reality with some sensory and imaginary content; for example, the statement 'When I watched you bend over just now I "saw" flames coming out of your ass.' It is an earthy and sometimes humorous form of embellishing. View any Gabriel Iglesias comedy act on Youtube or Netflix and you you will see exactly what I mean, if you pay closer attention to his act. Yes I know he's an Se-dom and a comic, so maybe he has an excuse (it's his job to do this because he's on stage and trying to entertain people), but Si does the same thing only in a different way.
For an Si statement I will use a more controversial example: "Give the benefit of the doubt to those who seek to know; but treat as potential killers those specimens of insolent depravity who make demands upon you, announcing that they have and seek no reasons, proclaiming, as a license, that they 'just feel it'." (Ayn Rand)
It doesn't matter, for this purpose, if Ayn Rand's psychology was Ni-dom or Si-dom. The statement above is strongly Si, as well as Thinking, but that's not part of my point, which is this part of the quote: "but treat as potential killers those specimens of insolent depravity..." Notice that Rand is not saying that those who believe in "because I feel it" are actually killers. She is saying we should "treat [them] AS" potential (but not actually as) killers.
In this, Si experience of reality comes from something projected from within themselves, nothing fantastical as with the Ni embellishment upon experience, but rather something that symbolizes, signifies (and mythologizes) a part of the past - as with 10-year-old Rand's personal experience of the Russian Revolution which changed her life forever, probably traumatized her, and led her and her dispossessed family on a 1000-mile foot journey through the harsh Russian winter to live with her uncle. Seeing Rand's "vision" in this way, using psychology and knowledge of her biographical background, leads one to more fully understand where she was coming from, objectively and without the usual knee-jerk hatred. To Rand's unconscious psyche, she was literally cast out of Eden in a very Biblical sense, and an instinctive knowledge of Good and Evil becomes manifest in the world around her.
The Si experience converts past experiences (often negative) into a mythology that becomes symbolized, even "concretized," within something in the present moment, as the block of granite is converted, by the sculpture, into something that "exists within" the granite and is "waiting" to find expression through the hands of the sculpture. Many Si-doms are artists (as Jung pointed out), having a vision that seeks to be released through the artistic medium, and not to be confused with the Ni form of vision. Perceptive types have a "vision," and it may seek expression through artistry (such as onomatopeic forms of poetry), but the form of the vision determines the content that is expressed. And this form is determined by fantastical N vs. down-to-earth S.
Through art, the artist seeks to beautify and structuralize forms that "exist within" reality, the artist can "see" how this form takes structure before setting hands to the work. The Pe type of experiencing imagines this reality, while the Pi type of experiencing envisions it.