Astrology’s myopia
[Do I make rods for my own back? I suspect astrologers will respond to this piece, just published as a Muse column for Nature news, by saying that I clearly haven’t understood what astrology is really about or how it is meant to work. That’s because they have no idea about it themselves – the maze of different theories and traditions is a nightmare. But I think I do know what astrology used to be about, back in the days when it was arm in arm with astronomy.]

Seasonal effects on birth physiology inevitably raises spectres of astrology. But that’s just ahistorical nonsense.

Near-sightedness, or myopia, may be more common in babies born in the summer than the winter, a team of scientists in Israel have claimed [1].

This is just the latest in a string of suggestions that the season of our birth may affect our physical make-up. Among recent findings of this kind are reports of seasonal effects in fingerprint patterns [2] and in animal gestation length and birth weight [3][4].

Like these earlier claims, the seasonality of myopia seems an entirely reasonable thing to suppose, since there is already evidence that exposure to strong light both before and shortly after birth affects the ability of the eye to focus properly. The effect, identified by Yossi Mandel of the Israel Defence Force Medical Corps and colleagues, is small, and seems to kick in only for moderate to severe cases of myopia, which are probably preconditioned by a genetic susceptibility.

So far, so plausible. But you know what I’m thinking? How long before this result is touted as ‘further’ evidence that there is something to astrology after all – that the celestial configuration can imprint itself on our bodies and minds?

We can surely expect this finding to be added to the growing list of scientific findings, so far including sunspot cycles, animal navigation, solar-terrestrial climate correlations and even Gaia theory, that some astrologers have presented as evidence not only that science supports astrology but that it is trying to appropriate its key ideas.

This isn’t the kind of thing one can nip in the bud, and I don’t delude myself otherwise. Let me say simply that all these Cancerians whose poor vision has no doubt made them introverted, bespectacled bookish types are presumably born in the Northern Hemisphere, since one must anticipate that the myopia effect appears in January in the antipodes.

No, I think it is perhaps more edifying to consider why astrologers wants to draw solace from science at all. Most notoriously, they cite the statistical studies of French psychologist Michel Gauquelin, who claimed to show in the 1950s that more successful sportspeople and athletes were born when Mars was “rising or culminating” – just as you might expect for the ‘warrior’ zodiacal sign, after all.

This ‘Mars effect’ can be found echoed in a recent claim that English football league players are almost twice as likely to be born between September and November. (Sceptics might wonder whether the fact that those birth dates make British boys older and thus often bigger than their school peers has anything to do with it.)

Actually, Gauquelin himself called horoscopes an “exploitation of public credulity”. But his research was extolled by the British astronomer Percy Seymour, who has argued in several books (most recently The Scientific Proof of Astrology (2004)) that the configurations of the planets, moon and sun can leave an imprint on us via their magnetic fields. “The whole solar system is playing a symphony on the Earth’s magnetic field”, he says; the ‘interference’ of these fields somehow affects the development of babies’ brains in the womb.

Oh, I know. It is only the thought of countless astrologers saying “He had no arguments against it” that rouses me to point out that a fridge generates stronger magnetic field in the average household than Jupiter does, or that there is not the slightest reason to believe that exposure to magnetic fields can alter infants’ personality in consistent, or indeed any, ways. But I’m not going to preach to the choir.

No, I happen to think that the truth about astrology is more interesting than this kind of silliness. I’d argue that one cannot simultaneously afford astrology its proper place in the history of thought and still believe in it today.

To say (as many scientists might) that astrology has always been nonsense is to say something more or less without meaning. No one can reasonably say that Aristotelian science was nonsense; it was a best guess that proved to be wrong. The same is true of astrology.

It relied on two principles: a correspondence between the macrocosm and the microcosm (“As above, so below”), and on the action of ‘hidden’ (occult) forces. The latter was a perfectly valid assumption: there was nothing to ‘see’, no bodies in contact, that explained magnetism or gravitation. The former – in part, the idea that events in the heavens governed those on Earth, perhaps by some form of astral ‘emanation’ – was part of a long tradition, dating back at least as far as Babylonia, for which the tides and the seasons supplied corroboration.

Yes, the tradition was mistaken, but not unmotivated. Certainly, it is a whole lot less arbitrary than the modern astrologers who have allowed the whims of an astronomical nomenclature committee to determine the astrological virtues of the Centaur planetoid Chiron, discovered in 1977 – named after a mythical centaur renowned for skill at healing, this captured outer asteroid is therefore now associated with astrological healing powers.

In any event, one foregoes the right to claim any justification for these ancient beliefs in modern science if one does not accept what those scientific explanations rule out too. When astrologers say (as one did apropos of Seymour’s work) that the moon affects the oceans and so why not our predominantly watery bodies, they are in effect disqualifying themselves from using gravity as an explanatory mechanism. (Just do the sums.)

More seriously, astrologers who might want to seize on the latest scientific findings, whether of summer-induced myopia or seasonality of sporting prowess, as proof of their beliefs are like theologians hunting for God in dark energy, or indeed scientists seeking to rationalize biblical miracles: they misunderstand the function of those beliefs in the history of ideas. Astrology ‘worked’ when embedded in ancient and medieval cosmologies, which were not scientific but metaphysical. The only meaningful point of scientific continuity between historical and contemporary astrology is not about finding new physical mechanisms for how it ‘works’ but about asking whether the psychological motivations for such convictions – most probably, a need to find meaning in and control of one’s life – remain the same.

But there’s probably more too. Astrology endures, according to social critic Theodore Roszak, because of the inspirational appeal of its rich, venerable imagery. “It has poetry and philosophy built into it”, he says. He’s right about that. All it lacks is veracity.

References

1. Mandel, Y. et al., Ophthalmology doi:10.1016/j.ophtha.2007.04.040 (2008).
2. Kahn, H. S. et al., Am. J. Hum. Biol. 20, 59-65 (2008).
3. Davis, G. H. et al. Anim. Reprod. Sci. 46, 297-303 (1997).
4. Jenkinson, C. M. C. et al. New Zeal. J. Agric. Res. 38, 337-345 (1995).