I have been interested in preferences, personality types and related topics for about two years, mainly as a by-product of a personal introspection process. For a long while, I have been quite enthusiastic about Myers-Briggs types, and saw the whole typology thing as an interesting model that can provide insights about ourselves. Nevertheless, I have now realized many of its pitfalls, like the often too categorical classifications and bogus descriptions, and more importantly the lack of scientific testability. I have studied some alternatives like enneagram, but these models seem to fall within the same class of funny, interesting but probably not very scientific toys.
So, my question: is it possible to devise a scientifically valid, testeable model for personality preferences or tendencies? Does something like "personality" exist or is just mumbo-jumbo?