The Slogan and What It Actually Claims
As above, so below is usually attributed to the Emerald Tablet — a short alchemical text of uncertain origin, probably composed sometime between the sixth and eighth centuries CE, though medieval tradition assigned it to the mythical Hermes Trismegistus. The full phrase in its most common Latin version is quod est inferius est sicut quod est superius — “that which is below is like that which is above.” The cosmological claim embedded in this phrase became one of the organizing principles of Western astrology: the celestial and the terrestrial are structurally correspondent. What happens in the sky is mirrored in what happens on earth and in the human body.
This is, on its face, a causal or at minimum correlational claim. If the positions of celestial bodies at the moment of birth correspond to the character and fate of the person born, then either the celestial bodies cause those characteristics, or both the celestial positions and the human characteristics are effects of some common cause, or the correspondence is meaningful without being causal — what Jung called synchronicity. Each of these options has different implications for whether astrology is deterministic.
Most contemporary practitioners, when asked directly, will say astrology is not deterministic. The chart shows tendencies, not destinies. Free will operates within the energies the chart describes. You are not your sun sign. But this modern framing sits in uncomfortable tension with how the tradition actually developed — and with what the strongest version of astrological claims implies.
The Stoic Foundation
Western astrology reached its classical form under the influence of Stoic philosophy — particularly the Stoic doctrine of heimarmene, universal fate. For Stoic thinkers like Chrysippus and later Marcus Aurelius, the universe was a rational, interconnected whole governed by logos — divine reason — that expressed itself through causal chains extending from the heavens through every part of the material world. Human beings were parts of this whole. Their natures and circumstances reflected the configuration of the whole at the moment of their emergence into it.
This is straightforwardly deterministic in the metaphysical sense. The Stoic universe has no gaps in its causal structure. Everything that happens is necessitated by what came before. Human freedom, for the Stoics, consisted not in escaping this causal necessity but in aligning oneself with it — understanding one’s nature and one’s circumstances and acting in accordance with reason and virtue within them. This is the original philosophical home of compatibilism: freedom as self-determination within necessity, not escape from necessity.
Early astrology, developed within this framework, was correspondingly deterministic. The chart described what the person was and what would happen to them. The appropriate response was not to resist fate but to understand it — and through understanding, to bear it well. The astrologer was a counselor in the art of acceptance as much as a predictor of events.
The Problem That Troubled the Ancients
Even in antiquity, the hard determinism of Stoic astrology faced an objection that practitioners struggled to answer. Cicero raised it in De Divinatione, and it has been repeated in various forms ever since: if the chart determines character and fate, what explains the dramatically different lives of people born at the same moment?
The twins objection is the sharpest version. Identical twins, born minutes apart, often live very different lives — different careers, different health outcomes, different deaths. If birth time determines fate, why aren’t their fates identical? The Stoic astrologers offered various responses — the few minutes between twin births are cosmologically significant, the twins’ different positions in the birth order introduce different conditions — but none of these responses was fully satisfying, and the objection remained a standing challenge to the tradition.
A more recent and rigorous version of the twins objection comes from research by Geoffrey Dean and others on what they called “time twins” — people born at roughly the same time and place who should, on astrological theory, have similar charts and therefore similar life outcomes. Studies following thousands of time twins found no significant similarities in personality or life events beyond what chance would predict. The objection that troubled Cicero has not been resolved by the additional two millennia of practice.
How the Tradition Responded: Ptolemy’s Compromise
The most influential attempt to resolve the determinism problem within the Western tradition came from Claudius Ptolemy, whose Tetrabiblos (second century CE) remains the foundational text of Western astrology. Ptolemy’s approach was to weaken the causal claim while preserving the correlational one.
Ptolemy argued that celestial influences were real but not absolute. The astrologer was like a physician: the physician can predict the likely course of a disease and recommend treatment that improves outcomes, but the physician cannot guarantee results. Multiple causes operate simultaneously. The celestial configuration at birth is a primary influence, but local conditions, upbringing, and the individual’s own responses to circumstance all modify the outcome. The chart establishes tendencies. Events depend on the interaction of those tendencies with everything else.
This is a significant philosophical move. It shifts astrology from hard determinism toward something more like probabilistic influence — a position much more defensible philosophically and much harder to test empirically. If the influence is real but admits of modification by other factors, then any outcome that diverges from the chart’s apparent prediction can be attributed to the modifying factors, and any outcome that aligns with it can be attributed to the astrological influence. The system becomes difficult to falsify.
Ptolemy’s compromise has been the default position of most Western astrological practice since the second century. Contemporary practitioners who say “the chart shows tendencies, not destinies” are essentially Ptolemaeans, whether they know it or not.
The Modern Humanistic Turn
The most dramatic shift in Western astrology’s self-understanding came in the twentieth century, through the work of Dane Rudhyar and the humanistic astrology movement he inspired.
Rudhyar, writing from the 1930s through the 1970s, reframed astrology explicitly as a psychological tool rather than a predictive system. Drawing on Jungian psychology — particularly Jung’s concepts of individuation and the self — Rudhyar argued that the chart was a map of the psyche’s potential, not a blueprint for external events. The planets were symbols of psychological forces operating within the individual. Transits and progressions described phases of inner development, not external happenings. The astrologer’s role was to help the client understand and consciously integrate the energies described by the chart, not to tell them what would happen.
This move effectively abandoned the deterministic claim at the level of external events. The chart could no longer “predict” a divorce or a job loss. It could describe psychological themes that might manifest through a divorce or a job loss, or through other events with similar psychological textures, or — if the individual engaged with them consciously — through inner transformation that expressed the energy without requiring an external crisis.
The gain was philosophical respectability. The chart became a tool for self-knowledge, its accuracy evaluated not by event-matching but by psychological resonance. The loss was testability. A system that is accurate when it produces psychological resonance and also accurate when external events match its descriptions and also accurate when neither happens because the individual has “transcended” the energy is not making falsifiable claims. It’s offering a framework so flexible that nothing could disconfirm it.
The Tension That Doesn’t Resolve
Contemporary Western astrology contains, without much acknowledgment, two incompatible claims that practitioners draw on in different contexts.
When marketing the system’s value, the language tends toward the predictive: natal charts reveal character and destiny; transits time major life events; synastry explains relationship dynamics. This is the language that attracts clients and generates compelling testimonials. It implies meaningful causal or correlational structure between celestial positions and human outcomes.
When defending the system against scientific criticism, the language shifts toward the purely psychological: the chart is a symbolic language for self-reflection; accuracy is experiential rather than statistical; the system is a tool for meaning-making, not prediction. This is the language that deflects falsification. It implies that the system’s value is entirely internal — generated by the reflection it prompts rather than by any external correspondence.
Both framings can be found in the same practitioner’s output, sometimes in the same reading. The tension between them is the central unresolved philosophical problem in Western astrology — and it has been unresolved since Ptolemy.
What “As Above, So Below” Actually Requires
The phrase doesn’t technically require determinism. Correspondence can be non-causal. The celestial and the terrestrial can mirror each other without either causing the other — they might both be expressions of a third principle, as the Neoplatonists argued, or the correspondence might be what Jung meant by synchronicity: acausal connection through meaning rather than mechanism.
But non-causal correspondence is philosophically strange in its own right. If celestial positions don’t cause terrestrial conditions and aren’t caused by them, what kind of connection is being asserted? Synchronicity is not obviously more defensible than causation — it’s just differently mysterious.
The honest position is that Western astrology has never resolved this question, and that the resolution matters for how the system should be used. If the correspondence is causal, the chart is a description of forces that operate on you whether you consult it or not, and ignoring it is like ignoring weather forecasts. If the correspondence is merely symbolic or synchronistic, the chart is more like a mirror — useful for reflection, not prescriptive about outcomes.
Most practitioners use it as both, depending on the context and the client. The ambiguity is probably load-bearing.
The sky is strange. So is the question of what it has to do with us.