Well, you could think that all processes happen in your brain, not really outside. but when it comes to extraverted functions, the internal processes are sort of projected onto the image coming from the external world. With Ne, its the possibilities of where something came form and where it is coming from.
i suggest reading this topics i made about N: http://www.typologycentral.com/forum...rt-simple.html
also i think that Ne and Si are are sort of the two sides of the same coin: http://www.typologycentral.com/forum...137-ne-si.html
i should clarify that what makes Si and Se different, is that with Se the determining factor in your psyche(what motivates you) is the intensity of the object perceived from the external world. with Si, its the subjective experience which gets triggered by the external world that is the determining factor. jung said that Se gets determined by sensuous experience and Si by aesthetic. this doesent mean that all types wouldnt have sensuous and aesthetic experiences, but when S is introverted, the aesthetic experience is stronger and has more value to the person(thus he orients himself according to it) than the purely sensuous experience and intensity of it. for example Se user might be more drawn into things(clothes for example) that look glittery or has a lot of details or are are pleasant to the eye some other way. while Si user would be more focused on the subjective experiences this glitter and those details bring out in him, not that he doesent see the details or the glitter, he just isnt motivated by them alone, but is motivated by the subjective experiences they bring out in him. but naturally this is bit more complex in real life, because we use other functions to judge those clothes and not just accept them as good based on perceptions. you could say that the lower in function alignment S is, more of it is judged.
when it comes to Ne, the possibilities triggered by the external world is based on this subjective experience of Si(which ofc has its origin in the external world). and the higher Ne is(which makes Si lower) in function order, less of the subjective experience of Si comes to consciousness.
and about the internal triggers. its about those things that are for example conclusions made about the external world or feelings caused by something external, but which doesent follow the objective data coming from your eyes(or data that has once been thought to you by yout teacher for example). but it doesent have to be conclusions or what ever based on external world, it can be conclusions about conclusions about conclusions about feeling about conclusions based on external world. i think that everything originally came from the external world, except what came from the collective unconscious(but explaining that would be bit too much for now and it just merely influences the conclusions of what came from external world anyways). for example einsteins(INTP) relativity theory is a good example of fine usage of Ne and Ti, it wasnt something that were observed and then said to be true, it was something that were conclusions made from possibilities triggered by the external world. you know sort of if this that and this are true, then there is no other way than E=mc2 or what ever. and his theory of relativity wasnt even proven until many years later, yet it turned out to be true. newton(INTJ) on the other hand shows more of Te and Se in his work on gravity, it was something that he directly observed and influenced on what he learned about alchemy. naturally he used Ni also, but thats just for removing irrelevant ideas coming from external world and to sort of weed out the grand idea, which had its ingredients from Se and Te.
what i meant was that NFs arent as prone to force T judgment all over like T types are and that T types need T judgment more often to be there for things to be accepted and NFs dont need it that often, thus NFs are more prone on accepting ideas that are "psychic" or what ever you want to call it.Much of this is beyond me right now. I am trying to work through it piece by piece. For instance, what do you mean by NFs only accepting things that can be judged with T? Isn't F the dominant judging function?