The pieces may come together all by themselves, but there is value in taking them apart and putting them back together. It deepens understanding.
Rule is not preliminary, but the truth it attempts to describe is.
What of the temptation then, if the tertiary is on the other side of the medial point?
I think we have rehashed the debate on validity and cultism and so on quite enough. This is a forum that has typology in its name. We are studying a system for what it is.
People have different uses for it. I have seen it used for good effect plenty of times in work situations, and edcoahing's examples drive the point home even more.
The point, first, is to do no harm. The next point is to use the system to broaden perspective in specified ways. The final point is to aid individuals' in growth, the same way that thinking about the superego, id, and ego does. That's what I think about it.
Psychoanalysis is not scientific in the modern sense, but it can nevertheless still be useful. That is why psychoanalists are sometimes praised by the American Psychiatric Association.