Each planet has in each sign of the zodiac a dignity or a debility.
A detailed analysis of the astrological dignities and debilities necessarily lead to the double dignities (chapter 2.7.1). Without it, the dignities of the classical planets (Sun, Moon, Mercury, Venus, Mars, Jupiter and Saturn) can not be reconciled with the dignities of the new planet (Uranus, Neptune and Pluto).
Now we also realize that the signs of the zodiac and the planets are divided into two groups:
Moon, Venus, Jupiter, Neptune, Faunus and Sun have their domiciles in the signs Taurus, Cancer, Leo, Libra, Sagittarius and Pisces and their exiles in the signs Aries, Aquarius, Capricorn, Scorpio, Virgo and Gemini.
Saturn, Mars, Mercury, Iustitia, Pluto and Uranus have their domiciles in the signs Aries, Aquarius, Capricorn, Scorpio, Virgo and Gemini and their exiles in the signs Taurus, Cancer, Leo, Libra, Sagittarius and Pisces.