Like your original description, I too have massive changes in emotional intensity. Often I will be shuffling through my iPod, and skipping through all the songs until I find one that gives me some kind of emotional satisfaction. Often I have a very deep response. Whether or not that is INTP in action, or just some form of nostalgia, I don't know.
Says here that "introverted sensing is the most nostalgic of all functions." As Si is our #3 function, I'd say they're not two separate things, but that one follows from the other: nostalgia is part and parcel of being an INTP by virtue of our capacity for Si. I don't know how I'd make it if that were my dominant function, though. Yeesh.
If I'm out in public, shuffling through my iPod, and "Acalanto" by Dorival Caymmi comes on, I have to shut it off or I'll just start sobbing violently. I tried to find a good version of it on YT to post here, but no such luck.
But I too am starting to suspect if emotion means less to other personalities than it does to INTPs. I have a great disdain for anybody who uses emotion to get what they want. I see emotion as a realm that should be off limits to manipulation. I place a high value on emotion, and hate to see it used as a tool for superficial things.
Just seems like other types experience emotions differently than we do. They can cycle through them and transition more smoothly. Those are the "even-keel" types who often do well professionally because they don't have these sudden, volcanic outbursts like we do. So I think we have to learn to recognize when this is happening, and find ways to manage and moderate it. That's probably one of the things that's enabled me to keep my job as long as I have (fingers crossed).
I used to think having these sudden, violent attacks of emotion was a personal shortcoming, a flaw to be corrected. That only made me angrier. Now I see it as normal, and just something to monitor, and to figure out when's the right place and time to let it all out. Works much better so far.
Thinking is the precise one when it comes to order and logic; feeling is fuzzy and inaccurate.
Feeling is the more accurate when it comes to seeing the overall picture of true values. Thinking fails as it inevitably makes logical mistakes in failing to see the overall picture.
Thinking describes; feeling directs. That is their purpose.
Yeah. I think emotions set the goal and logic helps you figure how to get there. I think logic works in service of emotion, or, at the very least, you use them in tandem to pursue values.
So where does this leave us with the thread title, "Fe description"?
If by that you mean, "Have we gone off-topic?", possibly. For a topic I've seen discussed as much as this one, I'd expect a few tangents. I suppose emotion sparks so much interest because it's like water: we all need it, but some of us have easier access to it than others, and some of us know how to handle it better than others. If I lived in the desert, I'd probably read a lot of news articles about water scarcity, but since I live near one of the largest sources of fresh water in the world, it doesn't come up very often. In both cases, though, this resource can be mismanaged.
It does bum me out that my ability to access and understand other people's emotions (Fe) is so weak, and that my ability to access and understand my own (Fi) is virtually nonexistent.