S/N
The more I understand the MBTI and Jung the more I think Jung had a better grasp on it and it's somewhat deluded. However, I think the MBTI is a good starting point and with it's popularity is hopefully bound to go into the right area.
The functions are very important, aside from the functions Jung mentioned Introversion and extroversion. I'm not sure where the Perceiving and Judging.
I've been trying to sort my thoughts on the matter of an accurate test based on pairing functions rather than focusing on each individual letter.
I particularly define the S/N axis as the different between brain preference. Intuitives would have a Right brain preference (for input and thinking). The right brain sees the abstract, bigger picture and general idea behind things. I would assume intuition as in "hunch" would be how the right brain responds to sensory information. Unconscious sensory.... Our conscious mind filters out small details, but our brain still notices them. In the purest definition of intuition I've had moments of it before.
When I was in middle school there was a phone call for our teacher I had a hunch about it being his wife, which I said aloud. Indeed it was and my friend thought I was psychic (we were in middle school). The chances that it would be our teacher's wife are probably higher than it would be anyone else (He didn't get a ton of phone calls or anything). In addition to this, the time of the day seemed to hint that it was more likely his wife. It was very close to the end of our day. At the time I wondered how I had known, but it seems like a few general details led to my intuition about it.
This happened in another incident where I knew I'd won this "lottery" drawing for a college giftbasket or whatnot. At first I didn't know how it was that I had such a hunch about it, but now that I look back I may have been aware of where my paper was place and more so the expression on the man's face was a hint. My first name is long and uncommon, my last name is odd to pronounce. I'm not sure at what point I had the "hunch", but I was sure about it before he said it. It seems few, small details like this are what lead to a hint. The annoying thing about this perception is that I can't actually recall details regularly for the life of me...
When details are paired with pictures I tend to remember better. For instance, I don't recall dates and names very well. However there's a picture in a book that says in 1818 Karl (something) had made a huge difference in the world, along with Charles Darwin 1806(?). I recall this, because of the pictures (I'm a visual learning with a visual memory [also said to be part of the right brain]), but it's extremely unusual for me to recall dates...
In a pure sense I think this "hunch" is what intuition is and what it means in contrast to Sensing. At the same time I also think, in the more general definition, it's a right brain preference.
We're taught that the left side of our brain is logical, but this is in a literal fashion. That is to say, a step by step, detailed oriented fashion. Like a sensor. I think sensors have a better time with remembering details and dealing with details. Their logic is actually what makes their problem solving more simplistic and straight forward. It also encourages an opposites complex (that is to say basically a good/bad axis. "If it works, don't fix it")
An intuitive makes a good problem solver because they're more right brained, they can think outside the box and consider the possibilities. They may not be detailed oriented, but are idea oriented. When they input information it's likely to be in a general sense, not a detailed one.
This makes the primary usefulness of a sensor that they probably have a better memory for details, the usefulness for an intuitive is that they can pick up the general principle. If you're somewhat read on the hemispheres of the brain I think this relates with S/N. Of course all people use both sides of their brain, even if it's split.
But here is an example of how the left brain and right brain work. I know I've given this example in a few places, it's one of those things that fascinates me... The brain has to be aware of space and where you are in a room all the time. The left brain keeps track of you and yourself, perhaps also certain objects. The right brain keeps track of where you are in a room, perhaps in a house, on a street...
The Thinking, Feeling difference doesn't seem as clear. I think it has more to do with the emotional mind and limbic system, but I've yet to really understand it. I can observe that feelers like to be personal and are concerned about people and also seem to have a hard time arguing logically. They get attached to things and places and familiarity. They also have a good/bad axis which is defined by how it effects people.
THUS and NF is going to be more willing to consider alternatives to current culture and ways of life. The familiarity/peace complex might keep them from wanting a lot of change though.
SFs are going to be positive on good/bad axis. This would supposedly be a double wammy. I'm not sure though, I don't know if I've met any SFs? I would assume SFs believe in the simplicity of a working system (sensing) and also see that a working system is good (for the people; feeling).
For thinking types it would seem that NTs are the ones who want to figure out how to change/fix the system and STs are the ones who want to keep the current system running smoothly. I think that NTs and NFs are both more likely to be curious. STs and SFs are likely to be more adventurous and active.