I don't know about this. Is this how you experience it, or is it just an idea? I definitely don't experience it like this, rather I think I can identify all the functions being used at a time, if I'm so inclined. If all are always being used, then that must be in very very subtle ways that we cannot observe ourselves, and that would make it useless to talk about functions. Still most people (in this thread for example) seem to understand themselves as being ruled by not more than one or two functions at the same time.
Could you give an example? My visions are very consistent, whether my Ti tries to make "sense" of them or not. Suppose that I *know* that in the future I will do this and this, because that is what my Ni sees. Then Ti can interfere all it wants to, try to analyze it, derive it from some underlying logics, but it won't be able to, as Ni doesn't play in the field of words and logic. I see what I see, and I only rely on Ti as a way of promoting my visions or ideas in front of others, using clear reasoning to make my point.
http://www.typologycentral.com/forums/317374-post29.html
This is a link to a single post I made in the other thread giving reasoning for the fact that all four functions must be used all the time.