Personality type = I'm an INTJ
The other types are listed there. There are numerous tests available on line and others that can be professionally done. I started it off as more of a curiosity, but it is very interesting for me to understand how to deal with people of other types. Being aware of these types allowed me to understand how they do.
INTJs apply (often ruthlessly) the criterion "Does it work?" to everything from their own research efforts to the prevailing social norms. This in turn produces an unusual independence of mind, freeing the INTJ from the constraints of authority, convention, or sentiment for its own sake ... INTJs are known as the "Systems Builders" of the types, perhaps in part because they possess the unusual trait of combining imagination and reliability. Whatever system an INTJ happens to be working on is for them the equivalent of a moral cause; both perfectionism and disregard for authority come into play. Personal relationships, particularly romantic ones, can be the INTJ's Achilles heel ... This happens in part because many INTJs do not readily grasp the social rituals ... Perhaps the most fundamental problem, however, is that INTJs really want people to make sense.
This often describes me to a tee. I sit around looking at my software development job around me and just amazed at why the 'does it work' criterion doesn't come into play. I couldn't understand people who would choose an unproductive action over a productive one. I couldn't understand how someone not respond to a truth or rational argument. That is until I began reading the types and comparing it to people I know.
There are people who don't care about the truth or improving the world. I don't say that as if their way of thinking is worse. Indeed, there are types who think almost exclusively as feelings. If something feels good or if they can empathize with an issue, then they care about it.
I wonder about politicians and think-tanks with great thinking ideas but don't apply the vigorous 'does it work' that an INTJ might. How does their personality type fit in?
I wonder how much of this comes into play with religion as well. Are the INTJs of the world naturally more truth seeking and skeptical of simply being told what to believe. They investigate and seek truth. But what use is all the truth seeking. Many may not care and simply wish to feel good and live a good life caring about how people feel and for social harmony?
It's quite interesting to say the least to understand these social types and how they affect thinking and how people reach decisions.