Intervals and Astrology

I haven't written an Astrology 101 post, so forgive me if all this is a little bit confusing. Those uninterested or unversed in music theory and/or astrology may want to hold off on this post.

What I want to try to do is talk about the relationship between astrological aspects and musical intervals. In astrology there are 12 signs, in music, 12 tones. On some level that is a superficial similarity, but I wonder if they don't fit together in an unexpected way.

The ancients - Boethius in particular - believed that the planets themselves rotated about the Earth in musical intervals. Ptolemy's "circular" orbits provided a basis for Boethius in his "Musica Universalis," often translated "Music of the Spheres." The planets whizzing around were not strictly audible, but the notion that they mirrored harmonic patterns was religiously, mathematically, and philosophically agreeable.

Now we know that not to be the case, of course. The planets behave in all kinds of strange, non-circular ways, influenced not only by the incredible gravity of the Sun, but by each other as well. Nevertheless, astrology - never a musical practice in itself - has endured. How astrology works and whether it does is a post for another time (yes, I know, I've got about a dozen of these "another time" posts). For now I'm more interested in the analogy between the twelve-tone scale and the zodiac.

In trying to map the zodiac onto the scale, it is immediately clear that direct mapping is impossible. Moving chromatically creates strange relationships. Aspects that should be pleasant turn dissonant, signs that work well together sound awful. And this makes a kind of sense. Astrology comes from the ages before well-tempered tuning. While mapping directly (C = Aries, C# = Taurus, etc) might make transferring from one sign to another easier, it doesn't reflect the actual essence of astrology. Similarly, before well-tempered tuning, it was impossible to modulate from one key to another. If you started in C, you could not move to D, because in D all of the notes would sound off.

Over time, new tunings were developed, pulling all of the natural intervals ever so slightly off so that modulation became possible. These days, the difference between a C and a C# is identical to the difference between any other two half-steps. This means that, while it is very close, the frequencies of C and G are not in a 3:2 ratio. The "Perfect Fifth" was sacrificed for modulation.

All of that goes to show, we shouldn't try to make our astrological analogy work with modulation. If we are dealing, for example, with an Aries, there is no reason to imagine transforming that Aries into a Capricorn. What good would that do us? Rather, I think it makes more sense to establish the commonalities between signs and intervals according to the base sign in question. In the end, this will end up looking similar across signs, but it will be impossible to assign C to a given sign, F to another, and Bb to another.

So let's kick it off with the great kicker-offer Aries. Imagining Aries as a tonic, what roles would the other signs play? Which are dissonant, and which are consonant? Which lead into or away from Aries?

The obvious first step is to establish which signs represent the fourth and the fifth. These are the most consonant and harmonically functional intervals. Given that there are two, and that they are meant to represent the closest relationship to the tonic, I believe the other signs of the same element - in this case Leo and Sagittarius, which are also Fire signs - are the most logical choice. Because Sagittarius comes "behind" Aries and Leo "in front" on the zodiac, I think Sagittarius should be the 5th and Leo the 4th.

ARIES:
4th - Leo
5th - Sagittarius

In other words, Aries lead into Leo, and comes out of Sagittarius. As a cardinal sign - an initiator - it makes sense that Aries would lead into the fixed sign - more stable and immovable - of the same element. Likewise, Sag is a mutable sign - meaning it tends to be an ending, cycling to a new beginning - making it a natural dominant for Aries.

Another important aspect is the opposition. While my first inclination was to put the opposing Libra in the place of the tritone, I don't feel that's appropriate. The tritone is the most dissonant relationship possible between two notes. While it is a kind of musical opposite, however, that does not make it an astrological opposite. Libra and Aries have much more in common than C and F#, because Libra and Aires are both cardinal and both masculine signs. Their primary point of difference betrays a fundamental sameness: Where Aries is concerned with the individual, Libra is concerned with partnerships. Both, however, are about the relationship of the self to something. Compare that to Taurus, which is about personal resources and appreciation of beauty. Aries and Libra may have much that is not in common, but they have much that is as well. Indeed, opposites are often closer together - in terms of context - than synonyms (consider: yes and no; yes and affirmative).

With all that in mind, I think Libra fits best in the spot of the flat seven. That is not a consonant interval, but not totally dissonant either. Its presence or absence does more to transform the key than any other. The presence of a flat seven turns a major key into a dominant, causing a need for resolution. The same could be said of astrological opposites; they shape each other tremendously, and if both are present in the same chart, it signals a need for resolution.

ARIES:
4th - Leo
5th - Sagittarius
b7 - Libra

The actual largest discrepancies in astrology are between signs at the quincunx (one sign away from opposition). While these signs are not directly opposed, they share nothing in common. For Aries, Scorpio and Virgo are 150 degrees away, meaning they are different elements, ordinality, and gender. Much more than opposition, these signs are dissonant when compared with Aries, and should therefore occupy the two most dissonant intervals, the half-step and the tritone. As for which should occupy which, the shared relationship with the planet Mars suggests to me that Scorpio and Aries ought to be at least close together, so I think they should be at the half-step. Virgo, on the other hand, has nothing in common with Aries at all, and is therefore the best choice for the tritone.

ARIES:
b2 - Scorpio
4th - Leo
b5 - Virgo
5th - Sagittarius
b7 - Libra

There is one more truly dissonant interval, but it is an interval that serves an important harmonic function. That interval is the natural seventh. Similar to the half-step, the seventh is "next to" the tonic, but unlike the flat two, it leads into the seventh. Works of Medieval polyphony often started with a seventh opening into an octave. With that in mind, the natural fit here is Pisces. Pisces and Aires do not share much in common, but Pisces flows naturally into Aries all the same. Pisces is the last sign of the zodiac, and signifies the end of winter, while Aries signifies the beginning of spring. The astrological New Year occurs on the Equinox, when the sun passes from Pisces into Aries. What could be more perfect than for Pisces to be the leading tone in the Aries scale?

Similarly, Aries leads into Taurus. As the "next step," Taurus fits naturally in the spot of the natural second. Again, this is not a consonant interval, but it is a natural scalar progression. With that in mind, I'll plug Taurus and Pisces into our picture.

ARIES:
b2 - Scorpio
2nd - Taurus
4th - Leo
b5 - Virgo
5th - Sagittarius
b7 - Libra
7th - Pisces

Which leaves us with the so-called "most harmonic" intervals, the 3rds and the 6ths. Functionally, the 3rd and 6th serve only to add color to a piece. What they determine, however, is the flavor of the sound, as flat 3rds and 6ths indicate a minor mood while naturals indicate major. Our four remaining signs are either at a sextile (60 degrees, or two signs) from Aries, or square (90 degrees, or three signs). Sextiles are regarded as "soft" aspects, but do not connote the same intense relationship that trines (which are also soft) do. Rather, they are a source of general ease, a kind of coloring of the basic function of the signs involved. Indeed, they are rather like the major intervals of the scale. Squares, on the other hand, are the classic "hard" aspects, indicating the major sources of challenge and effort in a person's life. That said, they also denote opportunity, and can be a source of great pride strength once mastered and overcome. For that reason, they make sense as "minor" intervals; central to the harmony of the key, not always pleasant, but far from crushing or dissonant.

As with the 4th and 5th, the "which sign goes where" game is simplified by the arrangement of the zodiac. The planets that come 'after' Aries make for a more natural fit as 3rds. This puts Cancer on the minor third, and Gemini on the major. This means that our progression from Aries to Taurus can follow naturally into Gemini as well (which follows Taurus). On the other side of the zodiac, Capricorn and Aquarius fill in the flat 6th and natural 6th spots respectively. Aquarius flows naturally into Pisces (which flows into Aries), meaning there's a nice symmetry to our "scale."

ARIES:
b2 - Scorpio
2nd - Taurus
b3 - Cancer
3rd - Gemini
4th - Sagittarius
b5 - Virgo
5th - Leo
b6 - Capricorn
6th - Aquarius
b7 - Libra
7th - Pisces

We could go through the same process with the other twelve signs, but I'll spare you (and myself). Ultimately, I think the arrangement would be similar: trines at the 4th and 5th, opposition at the b7, squares at the minor intervals, quincunxes as the most dissonant, and sextiles and semisextiles (30 degrees) in the 2nd, 3rd, 6th, and 7th spots.

What are the implications of this kind of arrangement? Hard to say. By looking at a chart one might be able to translate it's major aspects into music, but that would only be a heuristic analogy. On the other hand, I do think that the analogy fits remarkably well (much better than I would have expected), and is probably worth further investigation. Since I'll be doing some astrology at our cohort's end-of-quarter party tonight, maybe I'll find a way to turn some of my compatriots into music. And hey, at the very least, it's fun.