The Sky at Birth

Introduction

Abraham’s first argument for the one God was made against the sky. In the Qurʾān he sees a star in the night and says, “This is my Lord.” Then it sets, and he says, “I love not the setters.” The moon follows, and the sun, “greater” than both, and each goes down in its turn, until he says, “O my people, surely I am quit of that you associate,” and turns his face “to Him who originated the heavens and the earth” (6:76 to 79, Arberry).

The same book that takes the stars down from the throne keeps them as guides. “And by the stars they are guided” (16:16). They mark the road, and they mark the season.

That distinction is the subject of this essay. Abraham settled whether the stars rule a person. The question left is whether the sky at the moment of birth lines up with anything real in the person who was born under it, and whether the old map of the heavens and the new maps of the mind have been describing the same ground. There is more evidence for a yes than most people on either side expect, and it sits somewhere neither side tends to look.

One sky, two maps

The Compass of the Mind traced Jung’s types back through the four temperaments to the Hippocratic humours. The birth chart comes from the same Greek physics. Ptolemy’s Tetrabiblos, written in Alexandria in the second century, describes every planet by the four qualities of that physics. The sun is “heating and, to a certain degree, drying”; most of the moon’s power “consists of humidifying”; Saturn works “chiefly to cool and, moderately, to dry”; Mars “chiefly to dry and to burn.” Ptolemy calls these qualities humours himself: “two of the four humours are fertile and active, the hot and the moist,” and “two are destructive and passive, the dry and the cold.” His third book then reads a person’s bodily temperament and “the quality of the soul” from the sky at birth.

So the chart and the temperaments were built from one set of four, by people who thought they were describing one world. When Jung rebuilt the temperaments as four functions of the mind, he took the old structure into psychology with him, and he knew where else it lived. In a memorial address for Richard Wilhelm in 1930 he said astrology’s “value is obvious enough to the psychologist, since astrology represents the sum of all the psychological knowledge of antiquity.”

He used it in his practice. To the Indian astrologer B. V. Raman he wrote in English in September 1947:

In cases of difficult psychological diagnosis I usually get a horoscope in order to have a further point of view from an entirely different angle. I must say that I very often found that the astrological data elucidated certain points which I otherwise would have been unable to understand.

And to the French astrologer André Barbault in 1954: “There are many instances of striking analogies between astrological constellations and psychological events or between the horoscope and the characterological disposition.” He was careful about which way the debt ran. “Obviously astrology has much to offer psychology, but what the latter can offer its elder sister is less evident.”

What Jung wanted from astrologers was numbers. The same letter to Raman closes: “What I miss in astrological literature is chiefly the statistical method by which certain fundamental facts could be scientifically established.” He tried to supply some himself.

CaseJung's marriage horoscopes

For his essay on synchronicity, published with Wolfgang Pauli in 1952, Jung collected the birth charts of married couples. Astrological tradition holds that marriage shows in contacts between one partner’s sun or moon and the other’s, so he counted fifty such aspects in each pair and compared them with 32,220 pairings of people who were not married to each other.

He gathered the couples in three batches, and in the end “483 marriages, or 966 horoscopes, were examined.” Each batch peaked on a classical marriage aspect: “the most frequent aspect in the first was a sun-moon conjunction (10%), in the second a moon-moon conjunction (10.9%), and in the third a moon-Asc. conjunction (9.6%).”

His own verdict, in the revised text of the Collected Works (vol. 8, par. 901), was sober: “From the scientific point of view the result of our investigation is in some respects not encouraging for astrology, as everything seems to indicate that in the case of large numbers the differences between the frequency values for the marriage aspects of married and unmarried pairs disappear altogether.” He kept the result anyway, as a meaningful coincidence, “just what I call a synchronistic phenomenon” (par. 904).

The first numbers

The statistics Jung asked for arrived in 1978. The British astrologer Jeff Mayo had collected birth dates and personality scores from 2,324 adults, and Hans Eysenck analysed them with Mayo and Oliver White in the Journal of Social Psychology.

The prediction came straight from the chart. Astrologers call the six odd-numbered signs, Aries, Gemini, Leo, Libra, Sagittarius and Aquarius, positive or outgoing, and the water signs, Cancer, Scorpio and Pisces, emotional. On Eysenck’s own inventory, people born under the odd-numbered signs scored higher on extraversion, and people born under the water signs scored higher on neuroticism. In Ivan Kelly and Donald Saklofske’s summary, “all the positive zodiac sign groups had higher than average extroversion scores and all the negative zodiac sign groups had higher than average introversion scores.” Twelve groups alternated exactly as the tradition said they should.

The difference was small: in Geoffrey Dean and David Nias’s account, “the difference in mean E score between odd and even signs was only 0.7,” on a scale averaging about 13. But the sample was large, and they put the true p value at 0.000005, about five in a million, though the paper reported it by convention as 0.0001.

NoteGauquelin's planets

The French psychologist Michel Gauquelin had come at the question from another side twenty years earlier. In L’influence des astres (1955) he reported that eminent professionals were born more often than chance allows with certain planets just risen or just past the top of the sky: Mars for sports champions, most famously. A Belgian committee of sceptics, the Comité Para, repeated the test in 1967 on 535 athletes, 473 of them from Gauquelin’s own files, and replicated it, though it held its findings back for eight years.

Later he and his wife Françoise moved from professions to character. By Geoffrey Dean’s count, from the biographies of 1,980 notable people they took 52,309 words describing personality, and reported that the traits matched the planets: Mars with the champion’s temperament, Saturn with the scientist’s, Jupiter with the actor’s, the moon with the writer’s. Their mean effect was about 0.10. Two papers with Sybil Eysenck, in 1979 and 1981, tested planetary positions against Eysenck’s personality scales directly. When Ertel had four trained students extract the traits blind from the biographies of 110 eminent professionals, he found “no tendency for planets to be linked with the relevant trait,” so this part of Gauquelin’s work stands contested.

The calendar in the chart

The usual argument about astrology treats the sun sign and the season of birth as two different things. They are almost the same thing. The sun enters Aries at the March equinox and Cancer at the June solstice, so in any one hemisphere a sun sign is a month-long window of day length, temperature and light. If the season of birth leaves a mark on temperament, then the sun sign will correlate with temperament, because the sign is a name for the season.

And the season of birth does leave a mark. In the same issue of the Journal of Social Psychology as the Mayo study, two papers proposed exactly this: Smithers and Cooper’s “Personality and Season of Birth,” and Wendt’s “Season of Birth, Introversion, and Astrology: A Chronobiological Alternative.” Since then the measured effects have accumulated:

Study	People	Measured	Finding
Natale and Adan, 1999	1,584 students	Morning or evening type	More morning types among those born in autumn and winter than in spring and summer
Chotai and colleagues, 2001	2,130 adults, Umeå, Sweden	Cloninger’s temperament inventory	Women born February to April more often high in novelty seeking; men born then more often high in persistence
Chotai and colleagues, 2002	Adolescents	The same inventory	Novelty seeking higher for those born October to March
Rihmer and colleagues, 2011	366 students	Five affective temperaments	Four of the five (hyperthymic, cyclothymic, irritable, depressive) varied with season of birth

These are measures of temperament, the ground the typologies map. The effects are small and they differ by sex and by age, as the reversal between Chotai’s adults and adolescents shows, but they keep appearing.

There is a mechanism, too, and it was found in the brain’s own clock. In 2011 Christopher Ciarleglio and colleagues at Vanderbilt raised mice from birth to weaning under long summer days, short winter days or equal day and night, then recorded the clock neurons of the suprachiasmatic nucleus. The light of those first weeks shaped the clock that followed. Mice raised on long days had clocks with a narrower daily waveform and a shorter natural period, and clocks raised on short days were thrown further when later moved to long days. The paper’s title calls it imprinting: in mice, at least, the season of birth is written into the timing of the brain.

This is where the two maps meet. A birth chart records the moment of birth in the language of the sky. A season-of-birth study records it in the language of the calendar. When both are set beside a measure of temperament, they are measuring the same moment, and when the temperament varies with that moment, both will find it. The chart has been reading something real, in its own vocabulary, for two thousand years.

A second look at the famous test

The study most often cited against astrology is Shawn Carlson’s, published in Nature in 1985. Astrologers were given 116 birth charts, each with three personality profiles from the California Psychological Inventory, one of them genuine, and asked to pick the right one. Carlson reported that they did no better than chance, and concluded, as Suitbert Ertel quotes him: “We are now in a position to argue a surprisingly strong case against natal astrology as practiced by reputable astrologers.”

In 2009 Ertel, a psychologist at Göttingen, reanalysed Carlson’s own data. The astrologers’ first choices were right 40 times in 116, against about 39 by chance; but counting their first and second choices together, they were right 86 times against 77.3 expected, with p = .054, and their ten-point ratings of fit came out at p = .04. His summary was measured: the results are “insufficient to deem astrology as empirically verified, but they are sufficient to regard Carlson’s negative verdict on astrology as untenable.” The best-known disproof of astrology, read again, leans slightly the other way.

The sceptics’ case

The sceptics deserve a hearing, and several of their results are strong.

The first is self-knowledge. Kurt Pawlik and Lothar Buse retested Eysenck’s correlations in 1979, and in Kelly and Saklofske’s words, “the so-called astrological effect in their Hamburg students could be statistically ascribed to their self-attributions”: people who knew their sign’s reputation described themselves to fit it. Eysenck and Nias tested more than 1,000 children, who were much less likely to know what their signs were supposed to mean, and found no sign of the effect.

The second is size. Peter Hartmann, Martin Reuter and Helmuth Nyborg looked for any link between date of birth and personality in 4,462 American veterans, and between date of birth and intelligence in 11,448 young Americans, and reported in 2006: “In no cases did date of birth relate to individual differences in personality or general intelligence.”

The third is time twins. Geoffrey Dean and Ivan Kelly followed 2,101 people born in London between 3 and 9 March 1958, on average 4.8 minutes apart, through 110 measures taken at ages 11, 16 and 23. People born minutes apart were no more alike than people born days apart; the effect they could attribute to astrology was “0.00 ± 0.03.”

And in 2008 Alyssa Wyman and Stuart Vyse gave 52 students two personality summaries each, one real and one false, from a Big Five inventory and from a computer-drawn natal chart. The students “identified their real NEO-FFI profiles at a greater-than-chance level but were unable to identify their real astrological summaries.”

Each of these answers a narrower question than it seems to. Self-attribution explains why adults who know astrology fit their signs; it cannot explain the season studies, whose subjects were scored on temperament inventories and morning or evening habits and were never asked about signs at all. Hartmann’s personality sample was middle-aged men, scored on Eysenck’s scales rebuilt from an older clinical test; Chotai’s novelty-seeking effect was in women, on a different inventory, and Natale and Adan’s chronotype effect is a trait Eysenck’s scales do not measure. The time twins test the fine detail of the chart, the minutes that set the rising sign and the houses. All 2,101 of them were born in the same week of the same March, so the season, the part of the chart that the evidence supports, was the one thing they shared and the one thing the study could not test. And a summary written from a chart by astrological software is an interpretation several steps from the sky; Wyman and Vyse tested the interpreter.

What survives the sceptics is modest and specific. The minutes of the chart have found no support. The season of the chart has. A small, measurable share of temperament goes with the time of year a person was born, the zodiac has always encoded the time of year, and the psychological types describe the temperament. The three line up because they are looking at one thing.

Signs, not lords

The monotheist tradition was never troubled by a sky that marks the seasons. What it refused was a sky that decrees.

Augustine gave the classic argument. In the Confessions he tells of two children, Firminius and a slave’s son, delivered “at the same moment, so that both were compelled to allow the very selfsame constellations,” yet the slave, “the yoke of his condition being unrelaxed, continued to serve his masters.” In The City of God he turns to the twins Esau and Jacob, born together and, as the heading of V.4 has it, “very unlike each other both in their character and actions.” The argument tells against a chart that fixes a life. It says nothing against a season that leaves a small mark on a temperament, which Esau and Jacob, born together, shared.

The Muslim philosophers drew the same line. Ibn Sīnā wrote a treatise, Risāla fī ibṭāl aḥkām al-nujūm, refuting judicial astrology; as Sally Ragep puts it, the treatise “attacks astrology” and shows his “attempt to demarcate astronomy from astrology.” Ibn Khaldun gave a whole section of the Muqaddimah to “a refutation of astrology,” on the weakness of its achievements and “the harmfulness of its goal.” And the hadith that Abu Dawud preserves from Ibn ʿAbbās is blunt: “If anyone acquires any knowledge of astrology, he acquires a branch of magic” (Sunan Abī Dāwūd 3905).

What all of them refused was the step from sign to sovereign, from “the stars mark the season” to “the stars make the man.” The Qurʾān keeps the first and the tradition never needed to deny it: the sun’s course makes the year, and the year is God’s.

So the correlation is real, and it needs no powers in the planets. In the north, a child born in the long days of June and a child born in the short days of December have met different light in their first weeks, and their clocks carry it. The astrologer names that difference by the sign the sun was in, the psychologist finds it in a temperament inventory, and the neuroscientist finds it in the clock neurons of mice. They are reading one created order. Abraham watched the star set and turned to the One who made it rise. The stars guide, and they mark the seasons; the hand that sets them, and the hearts born under them, belong to Him.

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