Ishtirāk al-Kawākib fī al-Dalāla
Definition
This is Abu Maʿshar's doctrine that all seven planets share at once in indicating the make-up of every person born into the world — none acts alone. Each planet still carries primary indication over particular kinds of thing: the Sun over animal life as a whole, Mercury over humankind, and each over a particular organ — the Sun the brain and heart, Mercury the tongue and mouth, Saturn the spleen, Jupiter the liver, Mars the blood, Venus the kidneys, the Moon the stomach. The sharing is simultaneous, not stage-by-stage.
In Tradition
Abu Maʿshar holds that no single planet can account for a whole nativity, because a person's parts, qualities, and conditions all come into being together rather than one after another. Sound judgment therefore weighs the agreement or disagreement of all seven planets jointly, reading each in its assigned domain — genus, species, body-part, or quality — while never reading any one in isolation. The doctrine grounds the practice of synthesizing the chart as a whole.
In Practice
Treat this as the rationale for never delineating a planet on its own. When you judge a topic, first note which planet carries the primary indication for it — the Sun for vital animal life, Mercury for distinctly human and rational traits, and the per-organ assignments for bodily and medical questions (Sun the brain and heart, Saturn the spleen, Jupiter the liver, Mars the blood, Venus the kidneys and reproductive organs, the Moon the stomach). Then weigh how every other planet, by its condition and its agreement or disagreement with that lead planet, modifies the result, since all seven contribute to the same individual at once. Read the chart as a single simultaneous whole rather than building it part by part: a strong primary significator confirmed by the others reads well, while one contradicted by the rest is undercut. The same simultaneity principle warns against treating an isolated favourable placement as decisive when the wider planetary testimony disagrees.
Historical Origin
The doctrine is set out by Abu Maʿshar al-Balkhi in the Great Introduction to Astrology, Part I Tractate 4, where he argues that the parts of an individual come to be all at once and so require the planets to indicate together. The Great Introduction was edited and translated by Keiji Yamamoto and Charles Burnett.