The operating principal of the system of Astrology is that all things are created through the interaction of the base elements. The system first identifies what the elements are and then how they function. This is a sort of doing-the-border-first approach to solving a puzzle and so we will start with the “borders” as well. The territory itself is the sky, the heavens, all that which surrounds us. It is a circle, and it was noticed that our world is inside of that circle and as such, the borders of the territory are the walls of that circle.
The first thing we learn is that the walls of the circle are not all the same - it’s as if they’re made of different materials in different sections, but distributed evenly around the circle. Next it is said that in the areas made up of a particular material there are variations in how the material functions, but that within each type of material we see the same variations, and these also distributed evenly. These are known as the triplicities and the modalities and they show us the most important features of each section of territory known as a zodiacal sign.
In this diagram we see four colors assigned to the signs. Notice how they proceed in sequence each time, and consist of four groups of colors, with three signs assigned to each color. These are the triplicities and they tell us what the territory of each sign consists of in a substantial, material sense. In the same way that copper and zinc combined cannot produce water (because they are metals), Aries and Sagittarius cannot produce green, because they are red. It is also telling us that when we are in a red territory, regardless of which, there will be some continuity of result and the same is true for the other colors. While there are twelve individual signs they are materially similar in a fundamental way shown here.
Red in our diagram are the Fire signs: Leo, Sagittarius, Aries
Green in our diagram are the Earth signs: Taurus, Virgo, Capricorn
Light blue in our diagram are the Air signs: Gemini, Libra, Aquarius
Dark blue in our diagram are the Water signs: Pisces, Scorpio, Cancer
Remember that these are territories - physical places through which can be passed, and that is the primary importance of their “triplicity.” When anything is interacting with these territories there is a different reality that is being interacted with. If you pass through a territory that consists of water after passing through a territory consisting of air, how will the interaction differ? What is possible in one such material versus another? How will the same action produce different results? These are the considerations that are described by the triplicities. There is also a clue about how things are formed being revealed by the sequence itself as all things proceed through the signs in order of first Fire, then Earth, then Air, then Water.
So why are these sections divided into three parts, and scattered across the circle? That is where the second important territorial division comes in - known as the modalities.
Here we see that the signs have again been divided, but this time into three groups consisting of four signs each. Sharp eyes have already noticed that each of the three signs from a triplicity are now separated. What we are shown is that within each triplicity there are three signs, and that each of those three signs operates in a different modality. There are three modalities, and each triplicity has one of each. The modalities in our chart are:
Red in the diagram are the Cardinal signs: Aries, Cancer, Libra, Capricorn
Blue in the diagram are the Fixed signs: Taurus, Leo, Scorpio, Aquarius
Gray in the diagram are the Mutable signs: Gemini, Virgo, Sagittarius, Pisces
The modalities tell us about the role taken by the sign within the triplicity group. Cardinal signs initiate, Fixed signs maintain, Mutable signs give way. Notice again that the sequence is consistent - Cardinal, Fixed, Mutable - this is the sequence through which all things proceed.
In order to understand the nature of each territory in the circle we must consider the combination of these two sets of properties combined. This is the fundamental distinction that generates the division of the entire circle into twelve sections. The zodiacal signs are elements and the triplicities and modalities are the properties that define and distinguish them from each other.