☿Mercury
Mercury is the planet of mind and speech: how you think, how you express yourself, and how you exchange with the world.
Mercury never strays more than 28° from the Sun: it is always in the same sign as the Sun or in an adjacent one. It is the Sun's messenger, and that closeness is part of its nature—it has no agenda of its own.
It is the most ambiguous planet in the tradition: neither benefic nor malefic, neither fully diurnal nor fully nocturnal. It takes the color of whatever surrounds it, and that is where its reputation for changeability comes from.
What Mercury represents
Mind and speech: how you reason, how you learn, how you speak and write. Mercury's sign describes the style of thought, not its quality.
Also commerce and exchange in general—hence its Roman name, the god of merchants and of thieves as well. And short journeys, documents, siblings.
Its house says where your curiosity is played out, and its relationship with the Sun says how much autonomy your thinking has from your identity.
Dignities of Mercury
Domicile in Gemini (diurnal) and Virgo (nocturnal). In Virgo it is also exalted: it is the only planet in the tradition whose domicile and exaltation coincide in the same sign, which makes Virgo its best possible placement.
Exile in Sagittarius and Pisces, fall in Pisces. Pisces accumulates both debilities—another unique case: Mercury's precision dissolves entirely in the sign without edges.
Mercury retrograde
Three times a year, for about three weeks, Mercury appears to move backwards as seen from Earth. It does not go back: it is an effect of perspective, like overtaking a car on the highway, which for a moment seems to be rolling backwards.
The tradition reads it as review and a second pass: what is decided then tends to be redone, and what was pending comes back. It is not a catastrophe—it is a change of mode, from advancing to going over.
Popular culture has exaggerated this transit considerably. A natal Mercury retrograde, for instance, is not a defect: it describes a mind that processes inwardly and reviews before asserting.
Frequently asked questions
What does Mercury retrograde mean?
That Mercury appears to move backwards as seen from Earth, through an effect of perspective. The tradition reads it as a period of review and second passes, not as a bad omen.
Why is Mercury so strong in Virgo?
Because Virgo is at once its nocturnal domicile and its sign of exaltation, the only such case in the whole tradition. It is the best possible placement for Mercury.
Can Mercury be far from the Sun?
No: it never strays more than 28° from the Sun, so it always falls in the same sign as the Sun or in an adjacent one. That is why its relationship with the Sun—combust, cazimi, eastern or western—is a central part of reading it.