Astrology(noun): the divination of the supposed influences of the stars and planets on human affairs and terrestrial events by their positions and aspects, from Middle English astrologie -- Merriam-Webster online
At the outset, I must say I know little of the details of how astrology is practiced today. My refutation of its principles, then, might seem a little brash: How do I refute something without knowing what it is I am refuting? But please bear in mind that my only assumption about astrology in the following post has already been stated above: namely, that it presupposes the existence of an influence that affects humans on earth, and that this influence depends on planetary positions, particularly at the time of birth. (It might depend on other things too, but this does not invalidate the fact that it depends on planetary positions.) I understand that Indian and Western astrologers, and the Chinese, and the Native American, and no doubt the Aztec and Mayan in their time, all had different ways of doing astrology. Yet the following argument is sufficiently general to encompass all of them, as they presumably made the above assumption too. Do not, therefore, chastise me for 'outing the emperor's nudity while ignoring learned tomes on ruffled pantaloons and silken underwear'.
Frequently, I have heard people argue that astrology uses mathematics, as if this somehow gave it extra credibility. Numerology also uses mathematics. So does my five-year old cousin, though not in a sophisticated fashion. (After all, mathematics is logic, and infants have to be very good logicians in order to make sense of the world.) Yet, we know that infants can sometimes entertain very wrong notions about Nature: We trust mathematics only insofar as it presupposes reasonable assumptions about Nature. As a case in point, consider Ptolemy's model of the solar system, with its cycles and epicycles. The elaborateness of the mathematics involved did not guarantee its status as a good physical theory. [UPDATE: In retrospect, I believe this argument would have warranted a discussion on the metaphysics of truth. While interesting, it would be post-length in itself, so I'll postpone that argument for another post. In the meantime, please bear with me if the above argument appears unconvincing to you.] This argument, that the usage of mathematics, however intricate, validates any of its results, seems to me so irrational and crude that I shall not touch upon it further.
Frequently, I have heard people argue that astrology uses mathematics, as if this somehow gave it extra credibility. Numerology also uses mathematics. So does my five-year old cousin, though not in a sophisticated fashion. (After all, mathematics is logic, and infants have to be very good logicians in order to make sense of the world.) Yet, we know that infants can sometimes entertain very wrong notions about Nature: We trust mathematics only insofar as it presupposes reasonable assumptions about Nature. As a case in point, consider Ptolemy's model of the solar system, with its cycles and epicycles. The elaborateness of the mathematics involved did not guarantee its status as a good physical theory. [UPDATE: In retrospect, I believe this argument would have warranted a discussion on the metaphysics of truth. While interesting, it would be post-length in itself, so I'll postpone that argument for another post. In the meantime, please bear with me if the above argument appears unconvincing to you.] This argument, that the usage of mathematics, however intricate, validates any of its results, seems to me so irrational and crude that I shall not touch upon it further.
Let me begin my argument with the self-obvious statement: Supernatural influences do not exist. (In this context, 'natural influences' are those that are observable and measurable.) Indeed, the phrase 'supernatural influence' is itself an oxymoron. If there is an influence, it should be observable and measurable; if there is no measurable effect, we should not care about it. Notice that 'measurable' does not imply 'visible on present scientific instruments' - real influences, for example, can be measured statistically. In order to 'detect' (in the above sense) an influence, it is sufficient to use statistics and to show that, for example, on an average significantly more people born between certain date ranges become sportspersons or doctors.
In all the accumulated scientific knowledge of all the previous centuries, there seems to be no hint of any force even close to the type that would be required to produce such an influence on Earth. The only influence of the planets on the earth is the electromagnetic radiation we receive from them (it is a different matter altogether that much of this radiation in fact originated from the Sun and was later reflected off the planetary surfaces), and their gravity, neither of which are strong enough to actually drown out the ambient noise: (nearby obstetricians, tables, and walls produce a far stronger gravitational effect, and nearby electric lights and ubiquitous radio signals produce a far greater electromagnetic effect.)
Yet the absence of knowledge about such an influence does not imply the absence of the influence: Perhaps our science isn't developed enough yet. So let us, for the moment, assume that such an influence exists. It is certainly neither gravity nor electromagnetism, for we understand both these phenomena well enough to say that their influence on our futures will be negligible. What are the properties of the influence?
1. The influence acts only on humans, and possibly on other living beings, but not on things such as mountains or oceans. This seems to me very strange. A planet several astronomical units away is somehow able to influence puny-sized humans but not the Earth or other planets. (If there were such an influence on large objects, we would have discovered it by now. The most precise trajectories of the heavenly bodies can today be explained by gravity and general relativity. If there were an influence sufficiently strong to affect humans, we should have expected there to be a sufficiently strong influence on the earth's trajectory as well, and it should have been picked up in experiments till now.) Apparently there is something special about humans that forces a planet several AU away to influence each of us personally.
2. The influence scales in a very weird way with the sizes of the planets. The moon, Mars, the Sun, and Jupiter all influence us to more or less the same extent. (Certainly, there might be an order of preference, but the fact remains that they are all able to influence our future.) Why not Uranus, or Ceres, or Titan, or Ganymede? Any dependence of the influence on masses and distances has to be extremely complicated; no simple function of masses and radii would enable Uranus, Ceres, Ganymede and the Moon to produce a similar influence on earth. (For instance, we would have a hard time explaining why Saturn's influence is of the same order of that of the Sun. The Sun is 1,000 times as massive and about 1/9 times as far as Saturn. If the influence scales directly with the mass, then the only mathematically simple possibility is that the influence scales directly with the distance too (if we are to believe that Saturn produces a similar effect), but that would lead to an absurdity; it would mean that even tiny dust particles in far-away solar systems would have a much greater impact than either Saturn or the Sun. Likewise, assuming that the influence scales inversely with the mass seems ludicrous.)
This, however, does not mean that such an influence cannot exist. After all, the simplicity of currently observed laws is not required by mathematics as we know it; the Universe could have been a lot more complicated. The difficulty of constructing a mathematical model for the influence does not imply the nonexistence of the influence. In science, we have access to one tool, and one tool only: experiment. No matter how exquisite or beautiful your theory, it is useless if experiments contradict it. Nature simply doesn't care, it doesn't exist for our convenience. Why, then, did I present the two points in the previous paragraph as an argument? The answer is: 'Extraordinary claims require extraordinary evidence', and I sought to convince the reader that astrology squarely falls into the category of extraordinary claims. (Carl Sagan's famous quote on extraordinary claims is not so hollow as it first sounds. Consider Russell's famous teapot analogy: You are not only allowed, but expected, to doubt and disbelieve the existence of a teapot in the Asteroid Belt in the absence of scientific evidence, regardless of the dreams of some crackpot. In other words, you can make an intelligent guess on the basis of your present knowledge about teapots and the Asteroid Belt. However, if such a teapot is indeed observed, it must be taken as fact, regardless of our previous bias.) Let us, then, turn to the final part of my argument: Experimental evidence.
It turns out that experiments, far from furnishing the extraordinary evidence necessary, have conclusively disproven the existence of at least one kind of influence. For an excellent review, please look at:
http://www.astrology-and-science.com/d-meta2.htm
I shall only single out one test from the above. (As you can see from the above link, its results are fairly representative of the general consensus among serious researchers.) Recently, researchers (one of whom was a former astrologer) published results of one of the most elaborate studies undertaken: they tracked the futures of about two thousand 'time twins', babies born within minutes of each other at the same location. The researchers tracked (for about forty years) more than a hundred different parameters for each of the twins, such as occupation, anxiety levels, marital status, IQ levels, ability in art and mathematics, and general physical characteristics. If indeed the location and time of your birth determine your future, the studies should have found a definite positive correlation between the corresponding characteristics of the time twins. Instead, it showed no statistically significant correlation whatsoever. This result is characteristic of nearly every major study performed so far to test predictions. Of course, as expected, astrologers jumped to the defence of their charlatanry by claiming that a time difference of even minutes could manifest itself as a different 'house cusp', whatever that is supposed to mean. However, it is difficult to see how a former astrologer could entertain such negligence; furthermore, professional astrologers seem perfectly happy with information that is far less accurate, while drawing up birth-charts. I also doubt that such accurate timekeeping was available when astrology first gained credibility in the eyes of the public.
In spite of the sheer unbelievability of it all (stars affecting human desires -- really ?), and in fact in spite of such strong evidence to the contrary, why do so many people believe in astrology? I shall take up this issue in a future post. In the meantime, please leave your comments, particularly if you disagree with anything I have written above.
Yet the absence of knowledge about such an influence does not imply the absence of the influence: Perhaps our science isn't developed enough yet. So let us, for the moment, assume that such an influence exists. It is certainly neither gravity nor electromagnetism, for we understand both these phenomena well enough to say that their influence on our futures will be negligible. What are the properties of the influence?
1. The influence acts only on humans, and possibly on other living beings, but not on things such as mountains or oceans. This seems to me very strange. A planet several astronomical units away is somehow able to influence puny-sized humans but not the Earth or other planets. (If there were such an influence on large objects, we would have discovered it by now. The most precise trajectories of the heavenly bodies can today be explained by gravity and general relativity. If there were an influence sufficiently strong to affect humans, we should have expected there to be a sufficiently strong influence on the earth's trajectory as well, and it should have been picked up in experiments till now.) Apparently there is something special about humans that forces a planet several AU away to influence each of us personally.
2. The influence scales in a very weird way with the sizes of the planets. The moon, Mars, the Sun, and Jupiter all influence us to more or less the same extent. (Certainly, there might be an order of preference, but the fact remains that they are all able to influence our future.) Why not Uranus, or Ceres, or Titan, or Ganymede? Any dependence of the influence on masses and distances has to be extremely complicated; no simple function of masses and radii would enable Uranus, Ceres, Ganymede and the Moon to produce a similar influence on earth. (For instance, we would have a hard time explaining why Saturn's influence is of the same order of that of the Sun. The Sun is 1,000 times as massive and about 1/9 times as far as Saturn. If the influence scales directly with the mass, then the only mathematically simple possibility is that the influence scales directly with the distance too (if we are to believe that Saturn produces a similar effect), but that would lead to an absurdity; it would mean that even tiny dust particles in far-away solar systems would have a much greater impact than either Saturn or the Sun. Likewise, assuming that the influence scales inversely with the mass seems ludicrous.)
This, however, does not mean that such an influence cannot exist. After all, the simplicity of currently observed laws is not required by mathematics as we know it; the Universe could have been a lot more complicated. The difficulty of constructing a mathematical model for the influence does not imply the nonexistence of the influence. In science, we have access to one tool, and one tool only: experiment. No matter how exquisite or beautiful your theory, it is useless if experiments contradict it. Nature simply doesn't care, it doesn't exist for our convenience. Why, then, did I present the two points in the previous paragraph as an argument? The answer is: 'Extraordinary claims require extraordinary evidence', and I sought to convince the reader that astrology squarely falls into the category of extraordinary claims. (Carl Sagan's famous quote on extraordinary claims is not so hollow as it first sounds. Consider Russell's famous teapot analogy: You are not only allowed, but expected, to doubt and disbelieve the existence of a teapot in the Asteroid Belt in the absence of scientific evidence, regardless of the dreams of some crackpot. In other words, you can make an intelligent guess on the basis of your present knowledge about teapots and the Asteroid Belt. However, if such a teapot is indeed observed, it must be taken as fact, regardless of our previous bias.) Let us, then, turn to the final part of my argument: Experimental evidence.
It turns out that experiments, far from furnishing the extraordinary evidence necessary, have conclusively disproven the existence of at least one kind of influence. For an excellent review, please look at:
http://www.astrology-and-science.com/d-meta2.htm
I shall only single out one test from the above. (As you can see from the above link, its results are fairly representative of the general consensus among serious researchers.) Recently, researchers (one of whom was a former astrologer) published results of one of the most elaborate studies undertaken: they tracked the futures of about two thousand 'time twins', babies born within minutes of each other at the same location. The researchers tracked (for about forty years) more than a hundred different parameters for each of the twins, such as occupation, anxiety levels, marital status, IQ levels, ability in art and mathematics, and general physical characteristics. If indeed the location and time of your birth determine your future, the studies should have found a definite positive correlation between the corresponding characteristics of the time twins. Instead, it showed no statistically significant correlation whatsoever. This result is characteristic of nearly every major study performed so far to test predictions. Of course, as expected, astrologers jumped to the defence of their charlatanry by claiming that a time difference of even minutes could manifest itself as a different 'house cusp', whatever that is supposed to mean. However, it is difficult to see how a former astrologer could entertain such negligence; furthermore, professional astrologers seem perfectly happy with information that is far less accurate, while drawing up birth-charts. I also doubt that such accurate timekeeping was available when astrology first gained credibility in the eyes of the public.
In spite of the sheer unbelievability of it all (stars affecting human desires -- really ?), and in fact in spite of such strong evidence to the contrary, why do so many people believe in astrology? I shall take up this issue in a future post. In the meantime, please leave your comments, particularly if you disagree with anything I have written above.
