Astrology 101: Debunking The Dirty Dozen


As we were sat around MSS HQ (which, being skeptics and all, you’re no doubt 100% aware of the fact it doesn’t actually exist), it occurred to us that there is an awful lot of woo out there, and not everyone can be expected to be fully versed in every bit of it.  I’d never heard of Pascal’s Wager (as Mike charmingly announced to the world).  People we’ve spoken to had no idea why homeopathy and acupuncture were pseudomedicine.  Some forms of woo are so obscure people may not have even heard of them (please please please spend 5 minutes looking up Breatharianism, for your next ‘what’s the harm?’ conversation).  We’ll be giving a basic intro to the pseudoscience and fuzzy thinking behind some of those in the near future, as part of our ‘Skeptic 101‘ series.

Then there are the other topics – the ones where everyone knows it’s nonsense, but you might not have the facts to hand next time you’re accosted by a woo-peddler on the subject.  Bigfoot.  Crop Circles.  Dowsing.  For me, Astrology falls firmly into this second category.

Twelve signs, twelve months, twelve types of people.  In the whole world. From looking at the positions of the stars and planets at precisely the moment of birth, it’s possible to predict character, future events, love life and a whole manner of cold, hard facts about a person.  Except it isn’t.  Because that’s ridiculous.  We all know that.  So here’s your at-a-glance guide to the woo that is astrology.


How does it work?

It doesn’t.  There, done.  That was easy.

Wait, you need more?  OK OK OK.  Here goes – well, believers are pretty fuzzy on this.  A few things come up time and time again, though:

1. Gravity: ‘The moon’s gravity is responsible for the tides, and our bodies are made up of 70% water so imagine what the moon can do to us!  And that’s just the moon – there are so many other planets and things out there that are even bigger!’  Gravitational force as a working method for astrology is impossible – sure, there are some pretty big things out there in space.  But they’re out there.  In space.  Any mathematicians out there (reading this, I mean – not out there in space) will tell you the inverse square law takes gravity out of the equation – for every step you get away from an object, it’s gravitational pull drops off by a proportionally larger amount.  Two steps, and it drops off by four times.  Three steps, and it’s nine times weaker.  Twenty-five steps, and it’s six-hundred-and-twenty-five times weaker.  And those things are a long way away.  The upshot of this is, at the moment of birth the gravitational pull of the midwife’s gloves far far far exceeds all of the combined gravitational pull of everything out there in space.  Phil Plait makes this point a billion times better than I could, on his BadAstronomy blog.  That’s the benefit of a PhD and some genuine expertise/physics I suppose…

2.  Radiation and Electromagnetic Frequencies: Similar to gravity, but with the argument that radiation is the cause – that each planet and body emits a frequency that somehow interacts with us.  At the precise moment of birth. Why birth, and not conception?  Who knows.  Fortunately, inverse square law also kills off radiation and magnetic frequencies (you don’t have to move the paperclip far from the magnet before it’s completely unaware of the magnetic field, for instance).  Also, the biggest source of radiation and electromagnetic force in our solar system – by a looooooong way – is the Sun.  Yet the Sun isn’t so important in astrology, it’s more planets and star systems that seem to matter.  Go figure.  Phil Plait covers this very well too.

3.  Quantum Mechanics: ‘Some astrologers believe that planetary energies themselves generate events in our lives — and given recent advances in quantum mechanics, they may be right’ (Source: Astrologycom.com) Quantum theory is something that, as a skeptic, you’re going to wish hadn’t been discovered.  Or at least was kept secret.  Or perhaps at the very least was given a totally un-cool name that wasn’t useful for the titles of major sci-fi shows.  Because every woo-peddler out there uses quantum theory to bash scientists over the head – science doesn’t understand it, so it can’t rule out that quantum theory explains astrology/mediums/homeopathy/bogus chiropractic/aliens.  But, obviously, that’s just an argument from ignorance fallacy – quantum theory doesn’t explain that the world isn’t flat, other observations do (including being out there and seeing for ourselves that the Earth is round).  Quantum theory doesn’t rip up the rule book, we still have other science to separate real from woo.


How can we show it doesn’t work?

This is much much easier.  At the base of it, every astrological reading is essentially just a collection of barnum statements and other simple cold reading tricks.  As such, skeptical hero James Randi was able to demonstrate that when people are presented with what they assume to be individual readings tailored to their own data, they are likely to give the reading a very high score for accuracy – even when everyone is unknowingly presented with identical readings.

In his excellent book ‘Quirkology‘, Richard Wiseman tests the claims of a financial astrologer, picking stock investments using a star chart, against the random picks of a 4 year old girl called Tia.  Tia made a 4.6% loss; the astrologer lost 10.1%.  (Bizarrely, the control – an investment banker – lost 7.1%, so from these results at least, if you want financial advice you should head to your nearest nursery school!)

In 1968, French statistician Michel Gauquelin sent the horoscope for one of the worst mass murderers in French history to 150 people and asked how well it fit them. Ninety-four percent of the subjects said they recognized themselves in the description.  Just to be clear – ninety-four percent of French people are non mass murderers, so something else was going on with the reading…

In 1989, researchers in Kansas City went to five professional astrologers with the birthdate and location of convicted serial murderer John Wayne Gacy.  John Gacy was convicted for the murder of thirty-three men and young boys – murders committed using his cover as ‘Pogo the Clown’, a children’s party entertainer.  Without knowing who the birthdate and location belonged to, the astrologers gave readings describing Gacy as having a “well rounded personality”, that he could “offer a good role model” and that he would “be excellent for working around young people.” (republished in the Indian Skeptic, referenced in Quirkology)

In 2002, comedian Dave Gorman spent 40 days and 40 nights following exclusively the advice of astrologers.  At the same time, his twin brother (who, being born in the same location and at the same time, has an identical star chart) lived his normal life, as a control.  The results are very tongue in cheek, but tellingly their lives did not run parallel or in any way comparable courses.

Finally, and the most fun thing to do in my opinion – pick up a paper, and ask a credulous friend their star sign.  Read out the reading, and ask them casually how accurate they think it is.  Once they’ve confirmed that many of the elements were indeed accurate, you can merrily reveal you read them someone else’s star sign.  It’s that simple, that straightforward to debunk this old and entirely lame form of woo.


Further reading

Geoffrey Dean and Ivan W. Kelly
Is Astrology Relevant to
Consciousness and Psi?

, , ,

  1. #1 by Evidence Matters on July 12, 2009 - 15:47

    Why so much medical research is rot.

    Dr. Peter Austin examined hospital admission records and discovered that astrological birthsigns are associated with particular conditions. E.g., people born under Leo are 15% more likely to be admitted to hospital with gastric bleeding than other birthsigns; similarly for Sagittarians who are 38% more likely to be admitted for a broken arm.

    Dr. Austin does not endorse the above findings nor claim that they are meaningful. He used the findings to illustrate the inadequacy of commonly used statistical analyses that “run the risk of identifying relationships when, in fact, there are none”.

    But, nice use of ‘astrology’ that some might have found convincing.

  2. #2 by Redwinelover on July 13, 2009 - 08:39

    Apparently “Virgos are rational, practical, intelligent people who are able to think clearly thanks to the ruler of their Earth sign, Mercury. Because Virgos have such clear thought, they may be critical of others.”
    Ahhh… this sounds like me, so maybe there’s some truth in it? Ha Ha.

    OK, so I was one of those people who believed in the efficacy of acupuncture until I looked at the evidence myself. Kudos to MSS for kick starting the doubt!
    I can trace it back to a lecture on pain and behavioural problems, by an eminent referral vet, at a small animal veterinary conference a few years ago. She merrily informed us that the mechanism for how acupuncture worked was ‘well understood now’, although tellingly she didn’t elucidate on the explanaton! After a quick google search, I see that she is still running acupuncture clinics for pain at both the scottish vet schools, where she is an honorary fellow, and teaches acupuncture to both vets and medics.
    “The pain management and acupuncture clinic at the Small Animal Hospital continues to expand. Acupuncture cases will now be audited so that this treatment can be assessed and evaluated as part of the hospital’s general approach to pain and well-being. Acupuncture is a technique with a sound basis in neurophysiology and its study naturally includes the latest research on human and animal pain relief. It is not a panacea nor a substitute for diagnosis. It is particularly indicated for chronic musculoskeletal pain, but other conditions may respond and can be discussed prior to referral.”

    You can read her book “Essentials of Western Veterinary Acupuncture” at Google books.

    Acupuncture does seem to have almost crossed over from alternative to mainstream or orthodox medicine, whether veterinary or human. The Singh and Ernest book “Trick or Treatment” gives a great overview of how this happened, as well as links to more recent research. But it shows how we usually rely on trusting the opinion of people who should be more qualified than us to look at the evidence.

    I’ve never tried to cure a sick animal by giving it a foot massage, giving it water as medicine, or hanging coloured rocks around it’s kennel, as it’s ludicrous to think that any of those things would make a difference! But alternative medicine is unfortunately increasing in veterinary medicine now. When you look closely at most of those practice’s website’s they usually state that their treatments are ‘complementary’ as the animal will still require conventional treatment… mmm … I wonder which will be making the animal get better !!??
    Veterinary complementary therapies include homeopathy, acupuncture, western herbal medicine, traditional chinese herbal medicine, natural nutrition and dietary advice, flower essences, laser therapy, reiki healing, crystal therapy and cranial osteopathy.
    Although most of these treatments are really having an effect of the owners rather than the animals, I love the fact that the placebo effect has been well documented in animals too.

  3. #3 by Colonel Molerat on July 14, 2009 - 10:08

    Gaaaaah! You Leos are always so NEGATIVE!

  4. #4 by Marsh on July 14, 2009 - 11:07

    Good lord, you guessed I was a Leo? That’s remarkable, I’ve totally changed my opinion on Astrology now, Mystic Molerat has done it again!

  5. #5 by Colonel Molerat on July 15, 2009 - 09:58

    Yup, us Aries are naturally perceptive!

  6. #6 by Andy on July 19, 2009 - 15:10

    Excellent article. Further info here. This is what our newspapers dshould be like. Debunks astrology and references Stephen Hawking all in one article
    http://www.hindu.com/2001/04/10/stories/13100372.htm

  7. #7 by Elijah on October 16, 2014 - 08:56

    Good post. I learn something totally new and challenging on blogs
    I stumbleupon everyday. It’s always exciting to read through content from other writers and use
    a little something from other web sites.

(will not be published)