Please don't assume from this thread that I only approach type from a cognitive process/type function angle; I also use type profiles, temperaments, interaction styles - whatever seems appropriate for a given context (as well as many other systems, including the Enneagram and NLP). I'm a great believer in a flexible attitude to life, as it provides many more options and choices.
A good metaphor for the way I see the subject of typology would be an interactive map like Google Earth, with, say:
temperaments = continents
16 types = large nations
cognitive processes = different regions within a nation (forests, deserts, cities etc).
One can zoom out for a bigger picture, or zoom down to get more and more specific information. The cognitive processes themselves can be broken down into even smaller categories if desired, down to the equivalent of individual homes, people, atoms or sub-atomic particles. Or one can zoom all the way out into space and explore the unity we all share.