First Four, then Five; why not more temperaments?
Someone I had been talking to; the person who informed me of the God Created You book, in fact, told me of pondering the thought that there might be other temperaments yet to be discovered. Since Supine took a long time, perhaps there are others.
I actually once wondered then, if “new temperaments could be discovered” as well, but quickly realized that what we call temperaments are just abstract plottings on a 2D matrix, and they’re not really set in stone. The primary factors are expressiveness and responsiveness, or basically, what Galen called “hot/cold” and “wet/dry“, which he used to plot the temperaments with the ancient elements and humors.
Melancholic was cold/dry, Choleric was hot/dry, Sanguine was hot/wet, so the remaining temperament of Phlegmatic was left in the remaining corner, cold/wet.
The Arnos, by mapping the temperaments to the FIRO-B scoring system (which uses basically a Blake-Mouton style 10×10 grid) discovered that Phlegmatic was really moderate in both scales. Therefore, the former cold/wet (low expressive, high responsive) had to be a different temperament that was not recognized, but was evident in certain people not fitting into the other four. Because it was low in expressiveness, it looked like Melancholy, and his high want of interaction (setting him apart from that temperament) is not usually recognized.
So any “new” temperaments would be determined by lying somewhere else on this graph. There are already others, such as combinations of high in one scale, with moderate in the other. However, these are simply labeled “Phlegmatic” variations of the other temperaments. If it’s low in expressiveness, and moderate in responsiveness, it will be different from a regular Supine or Melancholy, so it is called “Supine Phlegmatic” or “Melancholy Phlegmatic” (which will both be similar, yet lean slightly toward the need of the suffixed temperament).
There are also the compulsive variations, which represent the highest expressive and responsive scores, and are in the extreme corners. In fact, the main APS Manual considers these separate temperaments, saying “there are nine temperament types” (I don’t know why the compulsives are considered separate ones rather than the Phlegmatic blends. The compulsives would actually be the purest form of the temperament needs. The further from the corners you go, the more moderated the need becomes).
So if you look at it, there are 17 different “temperament” groups on the matrix (five “pure” ones, eight “moderate” variations, and four “compulsive” variations). Since there are three areas of need, and you can be any one in each of them, that’s why this system has 4913 different blends.