It only makes sense that you could merge at least SOME aspects. Each personality theory has to exclude certain types of perspectives /approaches, just like a painting actually involves the purposeful limitation of certain shapes and colors, or a book involves the purposeful exclusion of certain words. [My sentence here only makes sense because I excluded every word not shown in it.]
Your sentence is intended to convey limited meaning. A person is not intended to convey meaning, it is. Yes you could use every word ever known to describe every person ever known in some way or other and yes this would be pointless. However to say this man is a man is just plain unsatisfactory and recently I've found the MBTI the same. Yes there are common behaviours and yes people have extrapolated some other behaviours but it seems the further you extrapolate the weaker the definition gets and I think that this is because the MBTI is based on limited information and was never intended to give such detail.
The process itself is based on cognitive processes and seems inherently linked to thought patterns and resulting behaviours. I don't think that the MBTI really covers temperament in any great deal and that's what leads to the great variation in the types.
A good example of this is the typical write up of an ENTJ. Usually this type gets slated as bossy and overbearing but I know of at least one ENTJ who exemplifies the more positive features of encompassing people's desires and needs into his plans and tends to produce schemes which work out best for the largest group of people without ignoring those more fringe elements. This I can directly attribute not to his type nor his enneagram (though that probably does encompass some of this) but his FIRO B scores. His positive feedback need is so high that when asked to write the score on the board he froze in case upon seeing his result the others did not give the positive feedback which he needed. That goes contrary to the normal ENTJ write up like chalk and cheese. Positive feedback ENTJ versus negative feedback ENTJ. At this point you have thirty two types (not including those on the cusp).
So if you can somehow use two in conjunction, you would think you could find more clarity in the points of intersection, as well as additional "pieces" of parts not covered in both.
That would be the aim yes. The problem I foresee is at what point do you start to remove clarity from the system itself to add detail to the individuals write up?
Perhaps it would be best if the systems are left separate but the manner in which they intertwine is studied so that people can better interpret the results from the various tests?
Ha, that last sentence was funny. But it's because the Five has to verify the information had no "spin" on it, so they can trust it. Otherwise their entire thought process (and any conclusion drawn) is potentially untrustworthy. So they go pick their own cherries so to speak.
Yeah with the additional problem of paranoia so that even if you attempt to bait your hook and get them to go and find out for themselves you either hit the "yes but that means leaving my cave dumbass" or the whole raised eyebrow and the "and why would you want me to do that?". Talk about awkward!!
Oh. I consider the Nine to make the INTP more people-friendly, simply because being a peacemaker demands the development of observable friendliness and people skills. Fives merely detach to "find peace," they do not actively engage others if necessary to make peace happen; so they are less "peoplefriendly" in some ways.
I'm not sure about people skills. As a T I tend to think of them as tricks. More a kin to an illusionists role than one of a people person. I'm not sure though.
I am not sure I agree on the "objectivity" part since I tend to associate that with detachment. I think the Nines create more balance if it is being used to minimize conflict/friction. The Fives create more balance in their thoughts, not externally in relationships.
The whole 9vs5 on the objectivity scale, I've found that compared to the 5s I talk to I'll spend a lot longer trying to balance out my idea against all the axis it depends upon than they will. Mind you I think that's mostly externally I'll do this and I spend less time worrying about the minutia within myself than perhaps the average 5 does. With so little frickin information though I could be well off
One thing though, this idea that 9s are only really concerned with balance to minimise conflict applies equally well to the principles of an idea as it does to disparate factions of people. Ergo a 9 can spend a lot of time trying to reach the best conclusion about a cerebral subject from all of it's perspectives. That is an attempt toward objectivity and something I've seen more effort made towards by 9s than 5s (regardless of type if I remember correctly).
Well, the caveat is that I don't think all MBTI types can be any enneagram type. Some combinations/overlaps would be rare or non-existent. ISTJ is much more prone to be at Six, if anything. I would have to think more about ISTJ and Nine, to figure out where any overlap COULD be... and whether I can imagine some potential environment influences/situations that could permit such an overlap.
I think that all types and enneagrams can overlap, just not in the obvious ways. For example wouldn't an ISTJ 9 show more of their ENFP qualities? Would they not be the font of all knowledge regarding behaviour and the ins and outs of the local politics so that they can best navigate the tricky undercurrents that people tend to nurture?
I'll admit the combination would be odd and probably a very small percentage but I don't see it as entirely impossible. It is however just these cases which I think shows the need to study the MBTI in context to other systems and measurements and shows it's flaws as a stand alone system.
Basically the MBTI is too simple and limited to be an authority. Without the other information you would be doing the equivalent of looking only at one pane of a persons Johari window and claiming to know them.