This is really hard for me to explain, but I'm dying to know if you ISFJs feel the same way, so here goes.
Do you ever feel like when you think to yourself, it's usually in the form of an emotion instead of words? Like, do you assign an emotion to everything, even if it's a bit subconcious? Do you remember a standard or fact by the way it made you feel and not as much by the facts, like you know exactly why you believe something, but you couldn't put it into words?
My only example would be when someone asks me what a certain word means. It could be a word that I use frequently and completely understand, but I won't be able to describe it with words. I've assigned an emotion to it, but I can't transfer that emotion to you. It may be that I learned the word through circumstance and can't describe how I came about it's meaning.
Sometimes I know all of the facts on why I believe in something, but I can't explain them in common terms. I'm wondering if this is just my lack of social skills or something. Maybe I'm just weird... this is just so hard to explain. xD