In the Pure Phlegmatic, phlegmatic stability organizes the form alone. The logic is to keep the configuration as long as there is no reason strong enough to change it. The image is the leaf, which feeds itself and goes on, quietly, without needing anything else.
This keeping is operational, not necessarily intellectual or political conservatism. The Pure Phlegmatic can execute well, be fast under a deadline, and learn to change states; what characterizes them is the relative cost of the transition and a preference for continuity, not incapacity or low energy. They can greatly enjoy company and explain with good reasons why they keep a commitment, but neither affection nor arguments are what holds their form together: change the people and the criteria, and continuity remains the main logic. An external obligation tends to sustain their action when their own drive wanes.
The good proper to this form is to maintain, sustain, not rush, and preserve the rhythm, protecting promises, practices, and people against the instability of every new impulse. The temptation proper to it is lukewarmness, and here the line must be drawn fairly: the difference between a good wait and lukewarmness is not in the clock, but in the object, in the concrete possibility of acting, and in the choice whether or not to sacrifice the known good to one’s own stability.
The mature form of the Pure Phlegmatic is to keep well and to change when truly necessary. They stay sparing with change, but no longer use the difficulty of the transition as the final measure of what they should do, and their serenity becomes a silent strength at the service of what deserves to last.