What is a sign's modality?
A modality is how a sign moves: cardinal signs start things, fixed signs hold steady, and mutable signs adapt. Each modality holds four signs, one from each element. Cardinal is Aries, Cancer, Libra and Capricorn; fixed is Taurus, Leo, Scorpio and Aquarius; mutable is Gemini, Virgo, Sagittarius and Pisces.
Three kinds of month
The modalities, also called qualities or quadruplicities, come straight from the seasons. Every season has three signs. The first opens it, the second is the season at its fullest, the third is already turning into the next. 1,2,3
Cardinal signs (Aries, Cancer, Libra, Capricorn) begin at an equinox or a solstice: spring, summer, autumn and winter in the northern hemisphere. The word comes from the Latin cardo, a hinge. Older books call them moveable signs. 1,4
Fixed signs (Taurus, Leo, Scorpio, Aquarius) fall in the settled middle of each season, when the weather holds. 2
Mutable signs (Gemini, Virgo, Sagittarius, Pisces) close each season and share in the weather on both sides. Traditional texts call them common or double-bodied signs, which is why so many of them are drawn as pairs: the twins, the fishes, the horse-man. 3
How astrologers read them
In modern readings the modality describes pace. Cardinal signs are given the urge to begin, fixed signs staying power and stubbornness, mutable signs flexibility and restlessness. Combined with the element, the modality gives each of the twelve signs a unique pair: Aries is cardinal fire, Leo fixed fire, Sagittarius mutable fire.
Older astrology used the same groups for timing. In horary and electional work a fixed sign was a sign of things that last, a moveable sign of quick changes, a common sign of matters that could go either way. 2,3
Which signs are which
Calculated facts only, worked out the same way the machine does it.
- Cardinal: Aries, Cancer, Libra and Capricorn.
- Fixed: Taurus, Leo, Scorpio and Aquarius.
- Mutable: Gemini, Virgo, Sagittarius and Pisces.
- Signs of the same modality sit 90° or 180° apart, so they form squares and oppositions.
Where the idea comes from
Era by era, with sources. More in the Reading Room.
- Classical2nd century CEPtolemy describes tropical (solstitial), equinoctial, solid and bicorporeal signs: the seasonal groupings behind the modern three. 5
- 1600s1647William Lilly's Christian Astrology treats a fixed sign on the Ascendant as a mark of a person of firm resolution. 2
- Modern20th centuryTextbooks settle on cardinal, fixed and mutable as the usual English names; 'moveable' and 'common' survive in traditional astrology. 1,3
Common misconceptions
“Cardinal signs are the most important ones.” Cardinal here means hinge, as in the hinges of the year. It ranks nothing. 4
“Mutable means unreliable.” In the tradition it means adaptable, signs that share in two seasons at once. 3
Questions people ask
Is the modality the same in the southern hemisphere?
The names stay the same. Aries still opens a season, though in the south it is autumn.
What is a quadruplicity?
Another name for a modality: a group of four signs, one from each element.
Why do signs of the same modality clash?
Because they are three or six signs apart, the square and the opposition, which Ptolemy called disharmonious. 5
Sources
- Cardinal Signs (Moveable Signs), Skyscript, Glossary of Astrological Terms (Deborah Houlding). Read on .
- Fixed Signs, Skyscript, Glossary of Astrological Terms (Deborah Houlding). Read on .
- Mutable Signs, Skyscript, Glossary of Astrological Terms (Deborah Houlding). Read on .
- Cardinal, Skyscript, Glossary of Astrological Terms (Deborah Houlding). Read on .
- Ptolemy, Tetrabiblos, Book I, chapters 10–19 (aspects, houses of the planets, triplicities), LacusCurtius, University of Chicago (Loeb Classical Library translation by F. E. Robbins, 1940). Read on .