I don’t mean by this simply that what they say is so vague as to be useless (though that’s true). I mean that what people want from horoscopes is the tingle of possibility. Here, too, there’s a kind of genius – or perhaps cunning would be a better word. Conventional commercial wisdom has it that you should always underpromise and overdeliver. The star-sign business does just the opposite – it overpromises and underdelivers, because it has recognised that it will never be called to account over the discrepancy. For those bored by the predictable plotline of their lives, horoscopes offer the glimmer of narrative twist – with their carefully unspecific talk of “challenges” and “romantic possibilities”.

For those in the grip of uncertainty, on the other hand, the studied fogginess of astrological guidance offers the consoling illusion of meaning. What’s being sold here is a kind of psychic plasticine – endlessly malleable into whatever shape suits you.Troubled Geminis can currently find this on Jonathan Cainer’s website, for instance: “The lives of people are mere blips on the radar screen of time. Even the structures and cities they create are but passing footnotes in the annals of history The mountains themselves will return to dust one day. Given all this, do you think that, perhaps, you are taking a certain matter a tad too seriously?” A perfect example of how astrologers never fire bullets, always buckshot. Someone out there is bound to be hit and persuade themselves, in a kind of delirium of false significance, that they were the target all along.If we can’t fully explain the increased incidence of the disease, though, we can ask whether there’s a cure If there is, it doesn’t lie in rational argument There have been serious studies of astrology, of course. The psychologist Hans Eysenck did one that appeared to confirm a correlation between certain star signs and introverted or extroverted personalities.

It was only after he’d performed the necessary control – using sceptics and very young children who didn’t know what personality they should have – that he realised the belief was creating the correlation, not the other way round (hard evidence, as it happens, for those who argue that this is not just “a bit of fun” – that it can affect its devotees).In another study performed by the University of California, 30 respected astrologers (respected by each other, at least) were given three personality profiles and a set of astrological data that related to just one of them. Asked to match personality to star sign, they got it right one in three times. Doing worse than this would have been significant; doing better would have been a gold medal – but all they could manage was a draw with pure, dumb luck.This should be a cause for rage in any sentient being. Not because astrologers are shamelessly duping the public, and the public shamelessly allowing themselves to be duped The gullible, unfortunately, will always be with us. But rather because researchers at the University of California unquestionably have better things to do with their time than try to prove that bullshit is bullshit. The faecal metaphor won’t quite hold, in truth, because while you can establish beyond reasonable doubt that what emerges from the back end of a bull is bullshit, the process is considerably more difficult with what comes out of astrologers.Most current practitioners are well aware of how weak their position is and have adopted a tactic of planned retreats. Don’t get tangled up in queries about “precession” or “tropical zodiac divisions” – they long ago got those approaches bracketed and are happy to lay down a harassing fire of arcane explanations.

Get beyond that, and you hit a barbed wire of pseudo-science – designed to bring the catch-22 of the paranormal into play – that anybody intelligent enough to cut a hole in the obstacle is usually too intelligent to think worth bothering with.They also have sacrificial battalions. Want to shoot down Mystic Meg? Go ahead, they say, use up your fire on her while we regroup on higher ground – just a bit further away from the lapping tide of ridicule. Of course she’s a joke, they concede, and a useful one, too – her sideshow manner bolstering the illusion that there’s a distinction between showbiz astrology and the “serious” kind (the latter solely identifiable by the fact that it costs a great deal more).Deep down, astrologers know that there is no insult to the intelligence grievous enough to drive their core market away. “Some say there is a scientific rationale and some say there isn’t,” Jonathan Cainer conceded recently. “I say, who cares? It works.” Well, it unquestionably works for him, sitting pretty on an income of more than £1m a year, and the object of frenzied dogfights between rival newspaper proprietors. He might not be able to tell your fortune, in short, but you certainly can make his If you’re stupid enough, that is..