I have been thinking about this since the time I've read about Ne being "outside the box" and Ni being "about the box". I think it is a fairly accurate idea and it matches my understanding of the 2 functions. I have also added here the 2 sensing functions and tried to lay them out in the hypothetical box. The examples that I will use to illustrate are based on how people looks at interpersonal relationships, in order to add an F flair (though of course, I may have a bias towards Fe) to the functions, instead of the usual T bias that comes when a thinker explains the functions.
Let us first define the box as the set of all "normal" human relationships. So here it goes:
Si starts with an exact single point in the box. Everything that is later encountered must be defined in relation to this original point. When evaluating a new point in the box, there must be something in it that can be defined according to the original point.
It will stay out of weird possibilities (outside the box) that cannot be comprehended realistically in relation to the points inside the box. This makes Si very hard to change as it must redefine its whole preconceived system of points when it encounters unfamiliar situations.
Thus, if Si were to be represented graphically, it would look like a set of points all inside the box, all connected by individual lines leading to the origin.
Our young ISFJ
When our young ISFJ sees that his mother always prepares his bath towel in order to prepare him for bathing, he takes note of such fact. He notes that his mother likes vanilla ice cream with rice sprinkles on top. He is aware that she likes to watch Latino telenovelas. He also notices that she gets mad when he plays with his toys up to 10 pm. And so on.. This set of facts make up his view on how his mother acts, and therefore helps him to deal with her. All of his actions in relation to his mother are all calculated based on whether he wants to please his mother or annoy her a bit.
When the ISFJ meets other people, say, a neighbor, he will operate on the same lens as he viewed his mother before. What sort of shows that she watches regularly? What is her favorite ice cream flavor? Will she also get angry if I stay up late? And so on...This body of facts will also be automatically stored as the "right things to do when I'm with X neighbor"
The ISFJ is a bit cautious about change, because every person must be defined meticulously from the ground up. All of the facts must be encountered and stored again in order for it to be effective. But once it does, be ready to be amazed by its "precision, accuracy, and consistency"
Ni does not single out on one single point as Si does, but chooses to see "about the box"--its edges and corners that define the whole box. It believes that in doing so, all there is to know will be understood. It does not concern itself with a single point because "it's just like any point out there, so it's all the same, it's also bounded by the same boundaries in the box, so the same rule applies". It is also fearful of change like Si, but in a different way. It fears not when it encounters new points but when the whole box itself changes. Because, if it does change, then it has to remodel a whole worldview to integrate not only the previous box, but the new set of points added or removed by the change.
Our young INFJ
(I will be using myself as an example) When I was a child, I was not that much aware of the little details that make my mom happy or sad as the ISFJ in the first example. But I knew that everything that she does for me all comes from the fact that she genuinely cares for me. Therefore, being young and naive, I casually assumed that every mother cares for her child genuinely. Therefore I faced the world with optimism and zest, believing that everyone out there is good. All human relationships are beneficial, and that I must go out there to experience and benefit from them. I don't have to know that this person likes this game or not...All I was guided by was with this optimistic idea about humankind.
But later I hear of moms abusing their kids, teenage bitches who abort, etc... I was depressed and could not stand it. Therefore, now I assumed that all mothers cannot be all good, there are still some rotten kind thrown in there somewhere. And I extended it to humanity in general--that there really are good and bad people amongst us. Thus I became more cynical and now try to hold back myself when I know that there are bad people out there trying to take advantage of me.
When I reached about 9 or 10, I don't know, something in me said that there really is no good or evil. Every act, which might be mistaken as really good or really evil, are all the same, that they are the result of the individual wills trying to live a life in this world. Everyone has his own sense or idea of how he can live his life. What distinguishes good from evil? Nothing, I said. Then why is stealing deemed bad? Because it stems from innate fear of losing our possessions. So everybody must "play fair" and not steal from anyone. That is, all the acts that we deem bad can really be traced to our fears, not because of them being "evil" purely per se.
I am busy for the day and I have to go, so I'm cutting it right here. Probably later in the afternoon (GMT+8), I would continue on Se and Ne, or maybe tomorrow. Feel free to comment though