Ecliptic-based house division: Porphyry.

This article on ecliptic-based house division is Part 3 of a three part series. To start at the beginning , click here.

Porphyry is a quadrant house system. In quadrant house systems, the ascendant defines the first house cusp, and the MC defines the tenth house cusp. This creates four sectors or zones within the circle of the ecliptic, otherwise known as quadrants.

Named after the third century Neo-Platonist philosopher and astrologer, Porphyry, this system was used from the earliest days of horoscopic astrology and was described by Vettius Valens in Book 1 of Anthology, his astrological textbook.

In the Porphyry system, the span of the ecliptic between the horizon and midheaven is trisected to produce three houses. This makes the houses very easy to calculate, you can practically do it in your head! Because the number of degrees between the ascendant and MC vary according to location, time of day and season, the quadrants are rarely of equal size.

The advantage of Porphyry houses is that the first house cusp starts at the degree of the Ascendant, and the degree of the MC defines the 10th house cusp, thus underlining the importance of angularity in horoscopic astrology.  In doing this, Porphyry anchors houses to the earth in that it is the local horizon that defines the start of the first house, and the local meridian that defines the 10th house cusp and MC.

One reason astrologers use quadrant house systems is for the same reason that they use the tropical zodiac: because they are tied to what’s going on in the sublunar world.  Just as the tropical zodiac is tied to the earth’s seasons, quadrant houses are tied in profound ways to the physical earth itself. The idea behind using quadrant houses is that they better reflect what is happening in the terrestrial world as opposed to the sidereal world.

Furthermore, with Porphyry, we distinguish and underline the difference between a planet being domiciled in a sign and a planet being in an astrological house. 

An astrological house represents things that are linked to the Earth that we live on, the domiciles are in the heavens. For example, we could have two planets domiciled in Aquarius,  with Mercury in Aquarius in the 12th House and Saturn in Aquarius in the 1st House (see chart below).

Left: Porphyry Houses (quadrant system) – Right: Whole Sign Houses

We lose this symbolism in Whole Sign houses (see chart above), but we get it back in quadrant systems and in systems where the 1st House starts with the Ascendant, which is one reason why ancient astrologers used quadrant house systems in addition to WSH cusps.

Granted that the Porphyry system is more anchored to the earth and that it is a quadrant system, it is still based primarily on the ecliptic. So, after a time, astrologers began entertaining the idea of basing the houses on celestial circles other than the ecliptic, perhaps ones that were more linked to the earth, such as the celestial equator and/or the prime vertical. This would bring us to a discussion of the space-based houses, which we will save for a future blog. For now, let’s move on to our conclusions of what we’ve covered so far…

We’ve been discussing the ecliptic-based house systems: Whole Sign Houses (WSH), Equal and Quadrant Houses.  Which house system should we use?

Which one to use depends on what system of astrological praxis one is following.  If you’re following Project Hindsight (Robert Schmidt, Robert Hand) and its followers, you’ll probably want to use mainly WSH, using equal and perhaps quadrant houses for planetary strength and length-of-life.  However, later scholars who reviewed the same material as Project Hindsight have recently arrived at alternative interpretations regarding Hellenistic house doctrine. Some seem to think that degree-based quadrant houses were used by the ancients for topics, in addition to planet-strength and length of life. These scholars conclude that the ancients (Dorotheus, Ptolemy, Valens, et. al) used quadrant houses for more precise readings, when the exact birth time was available. Exact birth times often were not easily come by in ancient Greece, in which case WSH were used.

This undoubtedly was most often the case (no exact birth-time) resulting in a highly developed Hellenistic technique of using sign-based aspects and houses for delineating a chart. Also, it made casting a chart less time consuming (no computers in ancient times), so it makes sense that degree-based houses and aspects were used only when a birth time was available and when a high degree of accuracy was called for.

However the ancient Greek astrologers may have calculated their house cusps, my policy with respect to these new scholastic findings is to keep an open mind and not fall into the trap of turning previous interpretations of the ancient Greek authors into dogma. On a practical level, my personal choice is to use both WSH and quadrant houses for topics in the context of natal readings.

Modern astrologers, of course, feel free to pick and choose whatever techniques work for them. If you fall into this category, I would highly recommend basing your choice on the celestial circles that we have been discussing. Keep in mind their symbolism, and use whichever house system corresponds best to the goals of your astrological tradition (ancient, classical, humanistic, psychological, evolutionary, etc.)

As we have seen, each house system is based on a different set of celestial circles, which render varying house cusps and sometimes put planets in different houses. Let’s say that this happens when using whole sign houses and Porphyry on the same natal chart (see example above).

Saturn jumped from the 12th House to the 1st House, oh dear!  What do we do?!?!  Which chart do we use?  Which one is “right”?

The answer to this question is that both charts are right; the only thing that is happening is that we are seeing the same native from different perspectives! It is not a question of choosing between one or the other.  Both must be interpreted.

So, when looking at a natal chart, I have found it is always best to try putting it in more than one house system to see if any of the planets change houses. When they do, I look at the changes with interest and delineate both.

Working simultaneously with two house systems often yields interesting information.  For example, if I’m using WSH and Porphyry or some other quadrant system, when I see a planet move from one house to another, I interpret both and see what resonates with the client. With clients who are past their second Saturn return, I have found that both usually resonate, representing different aspects or periods of their lives. For younger clients this is not always the case, because it may be that the symbolism represented in one of the charts has simply not happened yet.

Another thing to keep in mind is which house system we use depends on what we are attempting to do. 

For example, if we are focused on prediction, we might use one house system, in horary we might favor another, in natal analysis another.  Ideally, the house systems we use would be based on which celestial circles are used to determine the house cusps, and how the symbolism of those circles relates to what we’re trying to accomplish. For example, what is prediction? It is a form of fate. Where does fate come from? One way of putting it is that it is in the hands of the universe. It might make sense to use whole signs in that case, since the house cusps in whole signs are based in the heavens, rather than where we live on the planet Earth. On the other hand, if we are looking for a lost object, we might want to use a space-based system like Regiomontanus. We’ll talk about space-based systems in another article.

Moving on, in conclusion, I’d like to say that all the symbolism I’ve mentioned up to now are just ideas to get the conversation going amoung present day astrologers: traditional and modern. Rather than arguing in favor of one house system over another, it might make more sense to focus our research on which house system is best for which astrological technique based on the celestial circles that come into play.

I look forward to this discussion!