This is gonna turn some of you off, but I think some of you will find this intriguing:
Keirsey Temperament Theory
Keirsey theory is based on observable behavior rather than strictly mental processes, which makes quite a difference. Now there are a couple of different ways you can approach this. One way is to look at the separate indicators.
In MBTI and Jungian theory, the biggest distinction is between "extroverted," and "introverted," which give variants of the different functions. In Keirsey theory it's the least important since people tend to switch back and forth between the two more frequently than in anything else.
The first big divide in KTT is actually between Sensors and Intuitives, labels which have been trashed for "concrete" and "abstract," "observant," and "introspective," and "Earthlings" and "Martians," respectively.
Now, these divisions are more relative, not strictly defined in archetypal fashion. And, really the archetypes seem to fall apart upon further inspection anyway. What's the absolute difference between thinking and feeling? How can it be defined, since you'd have to use thinking or feeling to define the difference, which would only wind up becoming self-referential and thus full of fail.
So all the variants are integrated into wholes, and full personality profiles are created to establish type rather than separable functions. The whole is greater than the sum of its parts (which is a fancy way of saying you can never calculate all the parts so it's best to take an evaluation of the integrated whole instead).
Keirsey Temperament Theory is more of a pragmatic approach to personality theory - not, is this true to the ultimate underlying "meaning" of it all? - but, how can I get this to work for me or be beneficial?
The Four Temperaments
There are four temperaments which have been observed through the ages - now named Rationals, Idealists, Guardians and Artisans.
Quick synopsis: everyone knows that there are some people who like to babble about philosophy all day or talk about their faith to everyone they meet, or define their relationships, or reflect on themselves and society. And then there are the average joes who just work, eat and sleep or sidestep all that and die in motorcycle accidents and end up on celebrity rehab (but not necessarily in that order ).
There are so many crossovers between the two that it would take a lifetime of frustrated wasted effort trying to neatly draw lines between the two groups, but that's not the point. The point is, we all know that some people seem to prefer one side or the other more and more as the years go by.
Again, this is the first divide, but here we're trying to distinguish differences between temperament.
The other major difference is between what's called being utilitarian or cooperative. Some are users and some are losers. (Just kidding.) What I mean is, some like to shoot more for efficiency while others like to shoot for connected goals and values. Most everyone does some of both, but some prefer one over the other.
Some people like to rock the boat while others think it's wiser to be more accommodating and work with people, or even conform. Some are vehemently stubborn on finding the quickest path to the most beneficial goal while others believe that success is found in one's association or relationships with others.
The combinations of these extremes creates some interesting phenomenas.
Breakdown of the Four Temperaments
There are cooperative yet concrete Guardians (SJs) who take interest in being connected or associated with others in a very down-to-earth type of way, whether it be through school or church or work or watching the same types of TV shows as alot of other people, Guardians like to be acceptable to others so they naturally find themselves conforming.
Idealists (NFs) are cooperative yet abstract, so they're always trying to connect with people on a deeper level than just the surface. Whether it be through deep meaningful spiritual experiences or just reflecting on their spouse's sacrifice in giving up their favorite show for a night, they find pleasure in these types of underlying connections that most normally don't pay attention to.
Rationals (NTs) are utilitarian yet abstract, which amounts to strategizing, creating technology, laying out social and governmental systems, anything to produce long-lasting results through reflective thought. This is where we find the difference between pragmatism and practicality. They're pragmatic in the sense of being utilitarian but not practical in the sense of being "nuts and bolts" types.
Artisans (SPs) are utilitarian yet concrete, which creates people who ignore conventions and find the quickest route to success. Not tied to any particular obligations or reflective in nature, they're extraordinarily carefree and adventurous.
Now, what's interesting is that this creates some unexpected results. It cuts clear across MBTI distinctions and creates its own system.
Some of those you might not expect to be sentimental, in fact are in this new scheme. ESTJs and ISTJs, because of their cooperative nature, are a part of the Guardian group, which has a strong sense of family and belonging. But this is just the kind of unexpectedness we find in real life - the strict coach giving the team a morale-strengthening pep talk, or the father cleaning his rifle on the porch waiting for his daughter's boyfriend. They're tough-as-nails but somehow a strong sense of belonging is a part of their integral personality.
Also, a couple of the feeling types are utilitarian. But who hasn't grown used to the idea of the "girl next door" type who gives out sex as freely and generously as candy? Or the sensitive yet whimsical artist turning on the dime to take the next train to move out to the East Coast?
It goes even further. There are also further divisions such as "directive," and "informative." Some types like to ask and answer questions, or gather information for its own sake. Other types like to act and do, or hand out commands and find solutions.
Now, some of the sensitive Idealists are directive in nature, concerned more with actions and solutions. But who else but these types are the great reformers of culture like Martin Luther King, Jr who instigate rallies and demonstrations to create vast change, or the numerous counselors who gently prod their clients to make significant and immediate changes to improve their lives?
And some of the tough-minded Rationals are inquisitive in nature, which creates intensive thinkers like Socrates, who came up with the Socratic method, which is a process of constant inquiry in order to arrive at understanding. Or those clever inventors who constantly question established norms and push boundaries in order to create better working systems or products.
And this only scratches the surface of Keirsey Temperament Theory. There are many more criss-crossing patterns and innerworkings to this schematic than can be taken in by a mere casual acquaintance.
To be sure, life itself is extremely complicated and unexpected, so we should only expect any truly reality-based theory to be that way as well.