There has been some disputation over which theory to follow: the Four Temperaments or Myers-Briggs. Obviously, Myers-Briggs has gotten more attention from the mainstream psychologists. But how did this theory come about? Why does everybody think it's more credible than the four temperaments? Well I'll tell you what I think, whether you like it or not. :-) I think that Myers-Briggs is probably the four temperaments with a facelift. Just think about it. Most of the qualities that both Myers-Briggs and the temperaments use to determine the particular person are the same. However, there could be one way in which Myers-Briggs could be it's own system. You see, the temperaments do not tell you what your personality is. They tell you what your temperament is. This temperament determines what our inclinations are and how we tend to act and what we tend to do. A lot of outside factors mold these tendencies, and our personality is a result of this molding.
Since the temperaments don't determine our entire personality and Myers-Briggs does (I think), then perhaps it could be a credible system. However, I would like to make it know that I have heard some rumors about the founder (was it more than one?) of this personality type indicator. I have heard that he was involved in some sort of occultic practices. Now, I haven't done any of my own research to confirm this, but if it were to be true then that would be a reason for scepticism.