Bronze-level articleAstrology

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There are two ways to view the stars: as they really are; and as we might wish them to be.
Carl Sagan[1]

Astrology is the mass cultural delusion that the apparent position of the sun and planets relative to arbitrarily defined "star signs" at the time of your birth somehow affects your personality.[2]

According to the Faculty of Astrological Studies, astrology "explores the meaningful connection between mankind and the wider cosmos, the relationship between the movements of the planets and the inner world of human consciousness and motivation."[3] Some supporters like to emphasise that astrology is complex, and goes beyond just the simple "Sun Signs" people are used to[4] and others like to add amusing little rationales such as “Every human being contains every sign and every planet.”[5] Stripped of any fancier and woo-like terms, it is the belief that huge balls of rocks, liquids, gases, and nuclear fusion reactions millions or billions of miles away from Earth can affect the financial, sexual, emotional, and employment situations of individual carbon-based life forms on one specific planet. Put like that, it sounds absurd, yet unlike many practitioners of alternative medicine who like to hide the absurdities behind complex terminology or assertions of mysterious energies, even fairly "advanced" astrology is still pretty open about the fact it's predicting the future based on staring into the sky.[6]

This widely believed idea has never produced any worthwhile and conclusive predictions, in spite of having several different formulations across disparate cultures. As far as astrology produces falsifiable predictions, it has been thoroughly falsified as no better than guesswork. As all the "evidence" that it is true is only anecdotal, selectively reported, or made up, it is an excellent example of a woo explanation for something quite mundane.

Contents

[edit] Definition

A birth chart, as used by astrologers.

Because astrology is an ancient pseudoscience, its historical form can differ from the modern-day version. Indeed, there are many astrological traditions that vary from culture to culture, many associated with religions. Wide definitions of what constitutes astrology has been provided by historicians and anthropologists. Patrick Curry defines astrology most broadly as:[7]

The practice of relating the heavenly bodies to lives and events on earth, and the tradition that has thus been generated.

Astrology today is the common computation and consultation system used by modern astrologers to explain personality types and factual events of today in terms of planetary movements and positions in their system. This is slightly more complicated than using birth month (which is used in horoscopes, as many people are familiar with), although it is no less accurate. Indeed, thanks to a few seasonal factors (see birth month, below) this may actually be less useful. However, it allows astrologers to sell personalised readings and give the impression that they've actually put some work into it.

[edit] The scientific point of view

The scientific view, in the most candid form, is that astrology is a load of ancient nonsense that is, these days, perpetrated by ignorant fools or those wishing to exploit others. It is, for lack of a better word, crap. In the interest of being factual, honest, and accurate rather than merely rhetorical, the scientific point of view will be spread out in more detail below, but will come to the same conclusion: astrology is crap.

[edit] Potential forces

Some of the celestial objects that supposedly rule our lives as seen through the Hubble Space Telescope

Fundamentally, astrology is the assertion that stuff happening in space affects us here - astrologers may suggest that it allows for predictions, but such predictions would not be possible if a connection did not somehow exist. This section explores whether such forces could exist. Astrologers may claim straw man here, but if there was a theoretically possible way to determine future events (or dictate personality types) there would be some connection whether they like it or not.

There is no known mechanism whereby a person could be significantly influenced by distant celestial bodies. A psychological explanation - where pretty shapes in the sky sub-consciously alter people's moods, perceptions or desires, like an accidental form of advertising or brainwashing - is unlikely as stars and celestial objects don't tend to be visible during the day and, with the exception of very dramatic events such as eclipses, all look the same to the untrained eye. In addition, viewing the stars (in order to be psychologically influenced by them) isn't a prerequisite for astrology, as a predictive mechanism, working.

More "physical" explanations are equally unlikely - this requires briefly looking into the physics that could possibly be behind it. The fundamental natural forces in nature are the strong and weak nuclear forces, the electromagnetic force, and the gravitational force. The strong and weak forces are nuclear forces, and are not applicable to interactions between people and objects such as planets or stars - their strengths tail off so dramatically that they barely have any effect outside the nucleus of an atom, let alone at the macroscopic scale. Similarly, the electrostatic force - while acting at greater distances than nuclear forces - becomes completely negligible at modest distance, and does not act in any way over astronomical distance.

This leaves us with the one remaining "long distance" force; gravity. However, despite working over far vaster distances than other forces, it is still practically impossible for planets to influence actions on Earth. Gravity follows the inverse square law, that is, that gravitational strength is proportional to the inverse of the square of the distance. As distance increases, gravitational pull decreases very dramatically; something that moves to twice as far away exerts a quarter of the gravitational pull, something three times further away exerts a ninth of the gravitational pull. Newton's law of gravitation can be used to show that, at its closest approach to Earth, the planet Mars exerts approximately the same gravitational force on a person as a 50 ton fully-loaded big rig placed 15 yards from that same person. The star Alpha Centauri A has a mass of 1.1 solar masses and is one of the three stars closest to Earth, yet its gravitational pull on a person is comparable to that of a 100 gram cellphone at 9 meters. The moon and sun, being closer, exert more force on the earth and result in the changing of tides (although this system is a little more complex than "the moon pulls water towards it"). Astrology is often not limited to just these two objects with the highest degree of gravitational interference and even so, these should - like with water in the tides - affect everyone equally.[8]

The great distances of these objects produces a further problem. Their pull on us is very close to their pull on the Earth as a whole. This differential pull is the tidal force, and it goes as the inverse cube of the distance. Not surprisingly, tidal forces are even smaller than overall gravitational ones. The planet Mars produces as much tidal effect on us as a small sand grain (diameter: 0.1 millimeters) at 1 yard or meter, and Alpha Centauri as much as a small virus (diameter: 30 nanometers) at that distance.

Astrological forces, furthermore, are allegedly powerful enough that they cannot be escaped by shielding or descent underground. It is possible to evade electromagnetic radiation of all kinds. Although it is possible to protect oneself from electromagnetic radiation (radio waves, infrared and ultraviolet radiation, visible light, X-rays) and ionizing radiation by shielding or going underground, astrological 'forces' supposedly can pass through lead-lined shielding or several meters of rock or hundreds of meters of water -- the latter not creating its own astrological effects. Going into a mine, tunnel, cave, or submarine in an effort to avoid 'unfavorable' influences in one's horoscope gives one no protection (not that mines, tunnels, caves, and submarines are without their own dangers).

Whatever the mysterious force may be that astrologists claim causes the effects of the positions and movements of celestial bodies on human physiology, it is not backed up by any current knowledge or research and certainly isn't real. If there is a force, it can't be detected, and woo pushers tend to like that sort of thing — but this raises an important question; if it can't be detected in any way, shape or form, then how can it actually affect anything? However, we can still be open to so-called "supernatural" explanations and only look at the efficacy of astrology, treating it as a purely empirical question.

[edit] Birth month and other natural correlations

I don't believe in astrology; I'm a Sagittarius and we're skeptical.
Arthur C. Clarke

One force that almost certainly has an effect on people is the month they were born - though this has nothing to do with sun or star signs. Research in Queensland University showed that in the Australian Football League (AFL) there were 33% more players born in January and 25% fewer in December.[9] A sign that the solar cycles can affect your sports playing ability? Not at all; it's simply a case of when the Australian school year begins. Those born in January are nearly 12 months older than peers born in the following December, but are placed in the same school year - and the older ones are at a significant advantage at sports. When replicated in other countries with different distributions for the school year, the months where this trend appears shift accordingly.[10] This at least highlights some of the (very naturalistic) effects that need to be controlled for when assessing things like astrology; it is almost trivial to guess some trends but misread what causes them. In this case, the relative age effect is shown to have a cultural and location dependence, which would not be consistent with astrological predictions based on stars. The complexities involved in seasonal cycles to weather patters, sunspots and food production, mean that time and date almost certainly correlate with a multitude of factors that can appear as very real trends. The development of astrology may have been tapping into these observations, but then overextended the effect to things that were just plain wrong. What is certain, however, is that attributing these simple correlations to quasi-magical forces and star signs is wrong.[11]

[edit] Testing of predictive value

Assuming astrology does work, then we should be able to get a reliable definition of what "astrology works" means. In this case, it should provide a reliable source of accurate predictions and statements, and these should be better than randomly guessing once naturalistic explanations for any successes (or in less politically correct terms, cheating) has been controlled for. This is an important aspect of testing astrology, as practitioners are highly likely to worm out of such conditions.[12] The American Federation of Astrologers suggest that astrology is "all in the timing"[13] which can be read as a tacit admission that a prediction that happens to be wrong was just badly timed, and therefore shouldn't count. One of the great successes of woo movements is convincing people that it's legitimate to ignore such misses, and to think that a technique works except for the times that it doesn't. As a very good "technique works except for the times that it doesn't" is perfectly naturalistic guesswork, then holding up astrology to this standard is a perfectly valid way - indeed, it is the valid way - of testing its veracity.

Simple tests of horoscopes can be made by cutting the predictions and scrambling what signs they refer to - or perhaps asking astrologers and/or amateurs to match the description with the sign. As people happily read what they like into statements as vague as horoscopes, this never ends in astrology's favour.[14] A test titled "A Scientific Inquiry into the Validity of Astrology"[15] had this to say in its abstract, demonstrating a fairly easy test protocol that should differentiate astrology being reliable and being bullshit:

Six expert astrologers independently attempted to match 23 astrological birth charts to the corresponding case files of 4 male and 19 female volunteers. Case files contained information on the volunteers' life histories, full-face and profile photographs, and test profiles from the Strong-Campbell Vocational Interest Blank and the Cattell 16-P.F. Personality Inventory. Astrologers did no better than chance or than a nonastrologer control subject at matching the birth charts to the personal data; this result was independent of astrologers' confidence ratings for their predicted matches. Astrologers also failed to agree with one another's predictions.

While astrologers and believers may accuse science of being quite dogmatic over the "astrology is bullshit" line, rest assured it has been tested. If astrology was anywhere near as potent a tool as believers and astrologers suggest, results from even small-scale tests should end positively. One of the more famous and better controlled studies is the one performed by Shawn Carlson and published in Nature in 1985.[16][17] Here astrology was "given every reasonable chance to succeed", according to the author, but it failed. Astrologers were given the task of matching birth charts to personality types - a fairly simple task for a discipline that claims that your birth chart is "as unique as you are" and "reveals your potential in this lifetime and also where you are in that journey". Indeed, what would those phrases even mean if such a task couldn't be performed by an expert astrologer. However, astrologers themselves weren't best pleased with such a negative result, citing various issues with the apparently simple test. An article in the Astrology News Service is a curious example of kettle logic[wp] as it seems to simultaneously assert that the test was unfair and skewed, and so unlikely to show any effect, and that reanalysis of the data suggests the astrologers were correct[18]

[edit] Vagueness

Apart from Pluto, astrology does not take into account the dwarf planets - yet their gravity does have small pertubative effects on the orbits of other planets and the sun itself.

Predictions made by astrologers vary wildly from the vague to the specific - though most often they are extremely vague or at least vaguely in line with what most people think based on looking at the world around them, rather than the sky above. For instance, one prediction suggests "With Neptune in Pisces until 2024, we’ll see issues coming up in politics around water. There will be more flooding than ever before, unexpected hurricanes, tornadoes, typhoons and storms and towns and cities will disappear in the twinkling of an eye"[19] - which most climatologists suggest may well occur due to global warming. Indeed, other items mentioned in that prediction include "more products using nanotechnology", as if the increased use of a scientific buzzword was somehow only predictable through reading the stars and "expect to see huge growth in digital information clouds. At some point we’ll be able to stream all our music, TV, movies and books through subscription services. We’ll start to connect in new ways and we’ll know much more about each other" is bordering on self parody.

Generally, the more vague a prediction, the higher the chance it has of coming true. More accurately, the higher the chance that it can be interpreted as having been true after the fact, or retroactively reinterpreted as having not occurred because of some good graces. This can be seen most easily in the form of astrology that most people are familiar with; the horoscope. A horoscope is a prediction or advice based only on someone's date of birth, or more commonly (in newspapers and magazines, for instance) their zodiac sign, of which there are 12. Given that there are more than 6 billion people on Earth, at least one horoscope in every publication applies to more than 500 million people from the pigeonhole principle.[20] This gives more than enough room for even specific predictions to come true for a large number of people purely by accident. It is a clear fact that half a billion people do not have the same experiences each day, so the power of these predictions cannot be as widely and universally applied as is claimed.

[edit] Forer effect

See the main article on this topic: Forer effect

The Forer effect is where an over-generalised reading can be interpreted as very accurate by many people simultaneously. Often, Forer-type readings are very flattering or complimentary, but they can also mention hidden criticisms and insecurities that people realise they experience, but might not attribute to others and certainly like to hide. Therefore, by including statements like "you try to be bold, but worry about what other people might think of your actions and hesitate" you can give the impression you really did figure out new knowledge.

James Randi once replicated an experiment to demonstrate how people can basically be "tricked" into thinking a horoscope is accurate. A number of students were asked their zodiac and given the appropriate horoscope to read. They were then asked to grade how accurate they felt the horoscope was regarding their selves and a significant number, if not the majority, gave their horoscopes scores ranging from 4 to 5 (the maximum). Later they were asked to pass along their personal horoscope to the person behind them where the "trick" was revealed; they had all been given the same horoscope.[21] This is a demonstration of the Forer effect and how the language used in horoscopes can be vague and widely applicable to many people yet still give the illusion of being very specific. With a careful selection of language, phrases and tone, it is almost impossible for a horoscope to not to be applicable to someone.[22]

[edit] Value to science

Like many protosciences, astrology provided the original foundation of a modern science, in its case astronomy. As scientists started trying to understand what the bright things we see in the sky are, where they are, and their relationship to each other, astrology was able to provide some thousands of years of observations to develop hypotheses from. After all, mystics spent so much time gazing at the sky that it was inevitable some useful information would slip into human knowledge.

To a lesser extent, horoscopes - which would include fairly accurate astronomical data - of figures in the past and clear mentions of what were then "astrological" events may help modern historians with efforts to assign accurate dates to the past.

Whatever you do, however, do NOT confuse astrology with astronomy when talking to an astronomer—you will be soundly rebutted and possibly insulted. Even Chuck Norris wouldn't dare to mix up the two professions.

[edit] Social consequences of astrology beliefs

Want ads in China have been known to discriminate against certain star-signs. If you are a Scorpio, good luck finding a job there. We wish we were making this up.[23]

[edit] Quote mining

What utter madness in these astrologers, in considering the effect of the vast, slow movements and change in the heavens, to assume that wind and rain have no effect at birth!
—Marcus Tullius Cicero, 44 B.C.E
I don't know how many of you people believe in astrology.... (Girl in audience: You're a Sagittarius!) Yes that's right, that's right baby... (I love you.) I'm a Sagittarius. (I know. I read up on you....) The most philosophical of all the signs. (So am I.) But anyway, I don't believe in it. (I don't either) I think it's a bunch of bullshit, myself. But I tell you this man...I don't know what's gonna happen, man, but I'm gonna have my kicks before all the whole shithouse goes up in flames.
—Jim Morrison
Now you may find it inconceivable or at the very least a bit unlikely that the relative position of the planets and the stars could have a special deep significance or meaning that exclusively applies to only you, but let me give you my assurance that these forecasts and predictions are all based on solid scientific documented evidence, so you would have to be some kind of moron not to realize that every single one of them is absolutely true. Where was I?
—"Weird Al" Yankovic, "Your Horoscope For Today"
Astronomy is an exact science... Astrology is superstition.
Patrick Moore

[edit] See also

[edit] External links

[edit] Completely bullshit external links

None of these links are endorsed by RationalWiki but are presented (for your amusement only) as examples of the genre.

[edit] Footnotes

  1. A Personal Voyage — Harmony of the Worlds
  2. According to Dr. Sheldon Cooper
  3. Faculty of Astrological Studies - Why study astrology?
  4. Cafe Astrology - What is astrology?
  5. Astrology Energy
  6. American Federation of Astrologers - AFA Advanced Course in Relationships
  7. nickcampion.com
  8. Scientific American — Lunacy and the Full Moon
  9. Science Daily - Month of Birth Determines Who Becomes a Sports Star
  10. BBC News - How to build a champion: Be born at the right time
  11. Nature News - Astrology's Myopia
  12. The Double-Blind Astrology Experiment - see comments on this blog entry, for example.]
  13. American Federation of Astrologers - main page
  14. Paranormal Encylopedia - Astrology Experiment (spoiler alert; it just presents you with the standard Forer test. Like you didn't see that one coming, right?
  15. Journal Scientific Exploration. Vol. 4, No. I, pp. 75-83, 1990 (PDF file)
  16. A double-blind test of astrology, Nature 318, 419 - 425
  17. Skeptical Studies in Astrology
  18. Astrology News Service - Support for Astrology from the Carlson Double-Blind Experiment
  19. Astrological Predictions 2012-2013, Barbara Goldsmith
  20. Barring any birth timing irregularities, on average every horoscope should be applicable to around 500 million people.
  21. Astrological scammers sometimes give a very basic reading that's likely to be true for most people. They offer more detailed readings for a fee, spamming then goes on and on.
  22. YouTube: James Randi on Astrology
  23. China Job Ads Discriminate Against Scorpio and Virgo, The Telegraph
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