Quick answer: "As above, so below" is astrology's core axiom of correspondence: the heavens and the human world mirror one another, the macrocosm and the microcosm. The phrase is traditionally traced to the Emerald Tablet, a short Hermetic text known from Arabic sources, and attributed to the legendary Hermes Trismegistus. It is the premise that lets a birth chart be read as a meaningful map rather than a cause of fate.
Before astrology can mean anything, it needs one idea to be true: that the sky and the self are connected. Four short words carry that whole premise, and they come down to us from one of the most influential and most mysterious texts in the Western tradition. Understanding them is the cleanest way to see what a chart actually is, and what it is not.
What the Phrase Means
"As above, so below" is the axiom of correspondence. It says that the patterns of the heavens (the "above") and the patterns of human life (the "below") reflect one another. The older terms for this are the macrocosm, the great world of the cosmos, and the microcosm, the small world of the individual person.
This is not a claim that the planets push us around like billiard balls. It is a claim about mirroring. The same order that arranges the sky is held to be legible in the life below it, so the one can be read as a picture of the other.
Where It Comes From: The Emerald Tablet
The phrase is traditionally traced to the Emerald Tablet, known by its Latin name Tabula Smaragdina. It is a very short and famously cryptic Hermetic text, only a handful of lines long, that states the principle of correspondence directly.
The Emerald Tablet reaches us through Arabic sources, dated to roughly the 6th to 8th century CE. From there it passed into the Latin West, where it became hugely influential on medieval and Renaissance alchemy and astrology. Many later thinkers treated it as a kind of master key to the whole art of correspondences.
An important caveat: because the text comes to us through this later Arabic transmission, we should not assert a literal ancient-Egyptian authorship for it. What we can say is what the tradition itself says, no more.
Who Hermes Trismegistus Was
Authorship of the Emerald Tablet is attributed to Hermes Trismegistus, a name that means "thrice-great Hermes." He is the supposed author of the Hermetic writings, and it is essential to be clear about him.
Hermes Trismegistus is a legendary and composite figure, not a single historical person. He fuses two gods: the Greek Hermes and the Egyptian Thoth, both associated with writing, wisdom, and the crossing of boundaries. The body of texts tied to his name includes the Corpus Hermeticum, a Greco-Egyptian collection usually dated to around 100 to 300 CE.
So when older books credit Hermes with a teaching, they are naming a tradition and a legend, not pointing to a man whose dates we could look up. Treating him as legend is not a weakness of the idea. It is simply being accurate about it.
Why It Matters for Reading a Chart
This is where the philosophy becomes practical. The axiom of correspondence is the reason a birth chart can be read at all. If the above and the below mirror one another, then the arrangement of the sky at your birth can serve as a meaningful map of you.
- The chart is treated as a mirror, not a remote control.
- It describes correspondences and patterns, not fixed outcomes.
- It offers a symbolic language for self-understanding, not a forecast of fate.
This distinction is the heart of the matter. "As above, so below" justifies reading a chart as a reflection of the self. It does not license a fortune-telling cause-claim about what the planets will make happen. When you cast a free birth chart, you are working with that older premise: a symbolic mirror of the moment you were born, offered for reflection rather than prediction.
A Symbolic Language, Not a Force
It helps to hold the whole tradition in this frame. Astrology, read this way, is a language of correspondences. The sky is one text and the life is another, and the practice is learning to read the two together.
That keeps the art honest. It is grounded in a long historical lineage, from the Hermetic writings through medieval and Renaissance practice, while making no deterministic claim over anyone's future. The map is meaningful. It is still only a map.
Frequently Asked Questions
What does "as above, so below" mean?
It is the axiom of correspondence: the heavens (the macrocosm) and human life (the microcosm) mirror one another. It is the premise that lets a chart be read as a meaningful map rather than a cause of fate.
Where does the phrase come from?
It is traditionally traced to the Emerald Tablet (Tabula Smaragdina), a short Hermetic text known from Arabic sources roughly dated to the 6th to 8th century CE, and attributed to the legendary Hermes Trismegistus.
Was Hermes Trismegistus a real person?
No. He is a legendary, composite figure who fuses the Greek god Hermes with the Egyptian Thoth, named as the supposed author of the Hermetic writings such as the Corpus Hermeticum (Greco-Egyptian, c. 100 to 300 CE), not a single historical individual.
