Don that has me thinking too about another comment that was made tonight, I think by Tau Phi to Kalosyni, that in her example of thinking about a "jacket," that -- even for the same person - a "jacket" might one day be natural, might another day be necessary, and another day (possibly) be unnatural or unnecessary.
In other words, that virtually any single concrete desire we could name (excepting only extreme examples like "world dictator" or the like) might migrate between the categories based on circumstances.
If so (and i think it's yes) what does that do to the attempt to make the categories into a hard and fast list?