As a Ne dom i am currently trying to get in touch with my inferior function so i have noticed that i use Si when i stop using Ne that means when i stop exploring new things.That means that Si cares for that which is already known.It is very difficult seperating Si from Je but if i tried i would say that Si
perceives stuff from memory (the classic definition is the best). It is static that means that without Ne it can't change, and is quite literally you subjective version/opinion of reality.
Si is manifested in two ways ,
mental:This is the most obvious, it is what you know about reality(your subjective view) , for example everything you know about football is your subjective view of football ,its like your version of reality in you head i dont know hwo to say it , like the theory of forms of plato.
physical: This is when you have a subjective view of the outside world like how your house looks , or your daily routine , how you should live your day,
etc. etc. how something should look and you use Je to bridge it with reality.
Because Si users lack Se they have a thing for comfort though but thats not because of Si thats because they have low Se so the need for stimulus
from the senses is reuced.
Se is like Si directed outside , it is static , doesnt provide much new info in the psyche ,Se is experience, its experiencing things on the outside and generally doesnt care if what it perceives is the same thing over and over.Se wants to be fully involved with the objective outside reality, while Si is involved with the subjective reality.