Dean Burnett is a neuro-scientist who has a blog on Guardian Science Blogs, Brain Flapping, that is usually fairly humorous and mostly satirical. However last week he decided to take a pot shot at astrology that was rather banal, displaying, as it does, Burnett’s total ignorance of astrology both past and present. Basic rule, if you wish to send something up successfully you should at least be well informed about that which you are trying to ridicule. As I am currently preparing a public lecture on the history of astrology, I was halfway tempted to let loose another of my diatribes about the significant role played by astrology not only in the history of science but also in the cultural, social and political histories of Europe in the last two thousand plus years but in the end I couldn’t be bothered. On that score you will have to content yourselves with this excellent old post by Rebekah “Becky” Higgitt (that’s Dr Higgitt to you son), on misinterpreting astrology, and my response to it here, with a closing coda from historian of astronomy Lester Ness here.
However I can’t resist analysing Dr Burnett’s opening paragraph, which provides the hook for his attack, from a historical perspective. He writes:
It’s worryingly common to see people, even professional organisations, accidently use the term “astrology” when they mean “astronomy”. While phonetically similar, they are in fact very different things; astrology is an ancient system of divination, popular in several cultures, that makes predictions as to people’s personality and futures derived from the precise arrangement of planets, stars and other stellar bodies, whereas astronomy is a real thing that actually happens.
Now, if Dr Burnett were a little better acquainted with the histories of astronomy and astrology then he would be aware that the distinction he is so keen to impress upon his readers was for the majority of the last two thousand years by no means as clear cut as he seems to think.
Both terms go back of course to the ancient Greek words astrologia and astronomia. In the BCE period of Greek history they only used the one term astrologia, which means, “telling of the stars” and was originally applied to what we now refer to as astronomy, which the Greeks started developing around 500 BCE. As the Greek then started to develop, what we term, astrology from its Babylonian roots in the first and second centuries BCE they also referred to it as astrologia, because as Ptolemaeus wrote in the introduction of his astrology textbook, the Tetrabiblos, in the middle of the second century CE, the study of the heavens consists of two parts the first of which determines the movements of the heavenly bodies, which he had dealt with in his Syntaxis Mathematiké (Almagest), and the second of which determines the changes that these movements bring out, the subject of the Tetrabiblos. Two aspects of one discipline so only one name is necessary. Ptolemaeus used the name astronomia, which means, “star arrangement”, and was introduced in the first century CE specifically to describe what we call astrology! From this point onwards both terms, astrologia and astronomia, were used interchangeably to mean both astronomy and astrology.
The first person to differentiate between astrologia and astronomia was the seven-century CE Archbishop of Seville and encyclopaedist, Isidore, who used the terms as we do today, astronomia for our astronomy and astrologia for our astrology. Although Isidore’s encyclopaedia, the Etymologiae, was highly influential throughout the middle ages his linguistic innovation in the study of the heavens didn’t catch on and writers continued to refer to both disciplines with either term, indiscriminately. In fact you can find texts where the author will refer to astronomy as astronomia in one sentence only to call it astrologia a couple of paragraphs further on. Just to confuse the issue even further the three terms astrologus, astronomus and mathematicus are used totally synonymously from antiquity up to the seventeenth century. In a famous passage from Augustinus, where he seems to be condemning mathematics, because he warns Christians to beware of the mathematici, he is actually condemning astrology, which he thought worked because it was fuelled by evil.
Even in the seventeenth century, in the thick of the so-called Scientific Revolution, you can still find writers referring to astronomers in an astronomical context as astrologers. It was only in the eighteenth century that the two terms came to have the distinct meanings that we still use today, somewhat ironically, basically the wrong way round as astrologia is in terms of its origins the science and astronomia the system of divination. So should you make the, according to Dr Burnett unforgivable, error of confusing astrology and astronomy sometime in the future at least you now know that history is on your side.
 Astrologie: Wissenschaft oder Hokus Pokus? That’s Astrology: Science or Hocus Pocus? (Planetarium, Nürnberg 15 January 2014 7:00 pm). You are welcome to attend if you happen to be in the area.