> Essentially, you seem to be asking a number of questions:
1.) Can we identify characteristics of personality?
2.) Can we group individuals according to those characteristics?
3.) Can we now predict with any degree of accuracy what those groups of people will do in a specific situation?

yeah. i think that is a pretty good way of breaking the question up. one could ask (i think this is fairly much in line with your above schema):
1.) Are there basic traits that are predictive of behaviour?
2.) What are they?

> Generally speaking, I think the answer to all of the above is yes but obviously, there's margin for error.

yeah. it is an empirical question how predictive current traits are. they aren't very predictive, however (not much over chance). that doesn't rule out the possibility that there aren't traits that would be predictive, however, it might just be that we haven't found the relevant traits yet.

there are going to be exceptions. there isn't any reason why the behavioural predictions can't be probabilistic. it is just that we would want the traits to predict behaviours over half the time otherwise it isn't really predictive at all. there might be different thresholds for different traits. if i say someone is 'couragous' then what if he isn't couragous at all with respect to spiders and snakes? doesn that show he isn't couragous? maybe 'couragous' isn't an appropriate trait and maybe we need to go more fine grained. how about 'couragous in combat'? but what if the person is couragous under artiliary fire but not couragous against swords? do we need to go even more fine grained? is a person couragous in battle if he fights bravely nine out of ten times and flees one out of ten times or does such a behaviour undermine attributions of couragousness? i'm not sure. just creating trouble for trait theorists ;-)

> take the attributes of introverted and extroverted. These are fairly easy to identify within others and ourselves.

but i might be extroverted with a few close friends and introverted with strangers (or vice versa). i might be extroverted at office partys and introverted with my relatives. introverted when i have a headache and extroverted when i'm feeling happy and safe etc.

> My own experience of the Myers Briggs test -- like Fnordian Slip I've taken it several times over many years -- consistently scores me as introverted but there's less consistency on the other markers.

it might be that the test is really measuring... your self concept. since the test requires you to choose you choose. and the choices you make affect the way you see yourself which affects the way you answer the test in subsequent sittings.

> The current opinion is that the internalized experience of psychosis is one kind of disorder while the externalized experience of psychosis is yet another type of disorder.

i'm not sure what you mean by 'internalised' and 'externalised' experience. do you mean 'negative' and 'positive' symptoms or something else?

Brendan Maher might interest you (psychologist at Harvard, I think). He argued against the 'positive' and 'negative' distinction insofar as 'positive' symptoms are meant to be to do with the presence of something abnormal whereas the 'negative' symptoms are meant to be to do with the absence of something normal. He basically thinks that whether something is classified as 'positive' or 'negative' has more to do with how we describe it than anything else. For example, we could say that someone is socially withdrawn and describe that as an absence of normal social behaviours (hence it is a negative symptom). We could alternatively say that someone is occupied with their experiences and describe (the same behaviour) as a presence of abnormal self preoccupation (hence it is a positive symptom). I just mean to say that the positive / negative (hence?) introversion / extraversion distinction might be problematic.

> ...it's just my own meandering speculative attempts to understand as much as possible the experience known as psychosis in this culture.

:-)
I think that it is a very cool idea
:-)

> However, it may be more beneficial to think of oneself as an "introvert" or an "extrovert" as opposed to a "schizophrenic" or "bi-polaric" because there is far less stigma or shame associated with the labels of introversion and extroversion. Me, I'm an introvert and not the least bit ashamed of being one.

I hear you.

I'm thinking it might be more beneficial to think of oneself as having been in unfortunate situations. that there might be less shame in being something of a 'victim' of circumstances (environmental events or situations) that lie outside our control. and it may provide hope that there really isn't anything wrong with us at all... if only we could figure out a way to be in more fitting situations!

:-)

very cool ideas though, keep 'em coming.

here is a reference for some scepticism on the notion of personality traits:

http://www.cambridge.org/uk/catalogu...=9780521608909