Going back to some points
@Esther12 made earlier:
It takes me years of watching how people respond in a range of circumstances before before I feel like I have a sense of their personalities, and even then they will still often surprise me. Unless there have been amazing advances I'm oblivious too, I think that we'd be best off just being honest about our inability to meaningfully measure people's personalities.
I have to agree with you to some extent on this: personality and mind is such a complex multifaceted thing that it is almost insulting to try to reduce it down to three numerical values on three scales of measurement (even if those scales are reliably measuring something).
But the thing about psychology is that it is
trying to become a science; so it needs to
try to find things to measure.
I have some acquaintances who are quite anti-science. They argue that the physical world is far too complex and multifaceted to be ever captured in a simple equation or theory.
Yet along comes someone like Newton, and through all the incredible complexity of the world around him, manages to penetrate right into the bedrock of reality, and realize that some fundamental laws apply to all the complexity, laws that today we call Newton's laws of motion, and Newton's law of gravitation. These laws were used to put man on the Moon.
So the moral of the story would seem to be: don't give up looking for a scientific theory just because your subject matter is complex and multifaceted.
Psychological parameters like introversion-extraversion, neuroticism, perfectionism, or whatever are just attempts to try to measure aspects of the mind.
I think this reflects a misguided respect for the questionnaire.
I have to admit that when I took the EPQ, I was still quite young and intellectually impressionable (early 20s), so perhaps I did ascribe to it more significance than it deserves.
Though when I was doing this diploma course in personality theory, I was enthralled with everything I was learning.
The first time you learn any of the personality theories, you start to see that theory in operation in everyone around you. All of a sudden, all their words and behaviors seems to be perfectly explained by the theory. So for example, when you first learn Freud's theory of mental dynamics — his id, ego and superego aspects of the mind— you start see the id, ego and superego in operation as dynamic forces at play in the minds of everyone around you. You very quickly start to live and breathe this theory.
This initially makes you feel that the id, ego and superego tripartite model of the mind which Freud devised must be true, because you can see it everywhere. But then when you move on to study another personality theorist, and a different theory of the mind, then all of a sudden you start to see
that model of the mind dynamically in operation in all those around you!
Every time I studied a new personality theorist, this process would repeat itself: the new theory I'd just studied would seem self-evidently true simply because you could perceive it in operation in the minds of all those around you.
After you have studied a dozen or so different theories of personality — and they all seemed to ring true and seem to be present in the minds of others — you start to wonder if you are just projecting these theories onto your observations of other's minds. You begin to question whether these theories of personality represent real patterns, consistencies and regularities in the human mind, or whether studying such theories of personality merely configures
your own mind to see those patterns and regularities, when they don't in fact exist.
I still don't know the answer to that question today. But I certainly do know how seductive psychological theories of the mind can be to those learning about them, and how easy it is to start seeing that theory in action whenever you observe the minds of other people.