The rise and fall of astrology

Jim Harrison one of my regular commentators posted the following comment/ question on my post about the astrology wars:

Arguments about the legitimacy or illegitimacy of astrology in the past may make us lose the opportunity to study the downfall of astrology as a well-documented case of how scientific programs fail. I’m not a historian, though I read a lot; and I don’t have a very clear idea of how it happened during the 17th and 18th Centuries that astrology lost its legitimacy and was relegated to a sad after life in the Metaphysics sections of used bookstores. Its my impression that astrology lost its mojo in England around 1650. I’d like to find an explanation of how and why that occurred assuming I’ve got the dates roughly right. (Goethe began his memoir by summarizing his natal horoscope in his memoir (Dichtung und Wahrheit) in the early years of the 19th Century so maybe I’m assuming that astrology became crank science earlier than it actually did.)

A full answer to his enquiry would be more than book length but I will attempt an outline of an answer here.

The status of astrology in Europe, as we understand it today, and its respectability as an academic discipline has gone up and down like a roller coaster over the centuries since it emerged in ancient Greece in the 5th century BCE. In antiquity it reached a high point in the second century CE with the codification of its rules and methodology by Ptolemaeus in his Tetrabiblos, which would remain the bible of astrology up till at least the 18th century.

Following the appearance of Ptolemaeus’ book astrology went into decline along with the rest of the intellectual activities as the Roman Empire collapsed and with it civilisation in Europe. However it should be pointed out that the two most popular and well known astronomy texts in the Early Middle Ages, Macrobius’ Commentarii in Somnium Scipionis and Martianus Capella’s De Nuptiis Philologiae et Mercurii were both as much astrology as astronomy.

As civilisation and urbanisation returned to Europe at the beginning of the High Middle Ages, 1000 to 1200 CE, the renaissance of the sciences did not include astrology as one of the respectable discipline because of the dominance of the Catholic Church in education. For the Church astrology was suspect, and had in fact been strongly criticised by both Augustinus and Thomas Aquinas, because it seemed to contradict the Churches teachings on free will. However in the secular world those rulers on the boarders of the Islamic Empire, in Sicily or Spain, started to adopt the Islamic practice of having court astrologers as political advisors, the evil vizier of Hollywood film, in about the 12th century. This practice spread and by the 15th century nearly every European court had its own mathematicus or astrologus to interpret the stars, amongst other things.

Astrology entered the world of higher education with humanism at the end of the 14th century. The main driving force was the rise of astro-medicine derived from newly available texts from the Hippocratic corpus. In the 15th century humanist university in Italy and famously in Krakow established chairs for astrology and throughout the next two hundred and fifty years nearly all European universities offered Astrology 101 for medical students taught by the professor for mathematics. Nearly all of the leading Renaissance mathematicians were practicing astrologers, many of them court astrologers. Even Galileo, a practicing astrologer, routinely taught Astro 101 during his tenure as professor for mathematics in Padua. This is not to say that astrology was without its critics, the most extensive criticism of astrology being written by the humanist scholar Giovanni Pico della Mirandola (1463 – 1494), his Disputationes adversus astrologiam divinatricem, which contains all of the standard arguments against astrology still in use today.

Astrology continued to thrive well into the 17th century but went into a steep decline from about 1650. The big question is why? In general histories of science and cultural histories the standard answer, if they deal with the question at all, is that the new heliocentric astronomy killed off astrology as an academic discipline. This is completely false as any superficial examination of the historical facts immediately shows. As I wrote in an earlier post, Robert Westman famously wrote that there were only ten Copernicans in the entire world between the publication of the De revolutionibus in 1543 and the beginning of the 17th century and as a historian of astrology correctly pointed out all ten of them were practicing astrologers. Although Kepler, whose heliocentric system was the one that came to be accepted, rejected traditional horoscope astrology as it was practiced in his own times he believed deeply in celestial influence and wrote extensively about his own attempts to create a reformed astrology. So how are we to explain the loss of status of astrology in the 17th century?

The answer lies in another aspect of the scientific revolution. The Renaissance belief in astrology was based on the micro-cosmos macro-cosmos theory or as above so below. This theory said that the world of the heaven or celestial sphere is reflected in the normal world or terrestrial sphere and that the ability to read the one enabled predictions in the other. This philosophy was inherited from Greek philosophy and was also present in the interpretation of Aristotle that dominated mediaeval philosophy. As Aristotle was replaced as the foundation of natural philosophy by the new scientific philosophy of the 17th century and disappeared out of the academic realm the micro-cosmos macro-cosmos theory also lost its foothold in academia and with it astrology. Although this process was general throughout Europe it would appear that the reasons for the final loss of respectability for astrology varied from country to country. This has been researched in some countries, such as Britain, but not in others, such as Germany.

In Britain the English Revolution, or Civil War, played a major role in the demise of astrology. In the decades leading up to the English Revolution the social status of astrology was very strong and there was even a Society of Astrologers in London, which boasted many members of the intellectual elite amongst its supporters, such as Elias Ashmole and John Evelyn. During the Revolution astrologers on both sides used their reputations and supposed skills to make war propaganda for their troops, predicting victories and losses that were written in the stars. Following the restitution of the monarchy astrology fell into disrepute because the puritan astrologers had been more successful than the royalist ones. The Society of Astrology was also suspected as being a secret puritan organisation and so the members dissolved the society to remove the suspicion. The fashions in medicine also changed throughout the 16th and 17th century and by 1700 at the latest astro-medicine was out and Astro 101 was no longer part of the university curriculum.

In the 18th century astrology was still alive and well but was no longer part of the academic establishment however in the 19th century not only astrology by the occult sciences, in general experienced a surprising social renaissance amongst the well heeled and well educated. There were great fashions for things such as spiritualism, theosophy and other forms of mysticism and magic. Perhaps most notoriously in Aleister Crowley’ s Golden Dawn a rebirth of Renaissance hermeticism. I know too little about the subject to say why this occult renaissance took place but Dr SkySkull at Skulls in the Stars has an interesting post on one aspect of the subject.


Filed under History of Astrology

42 responses to “The rise and fall of astrology

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  2. Mike

    Nicholas Oresme wrote a refutation of astrology in the 14th century, based on the use of what today we would call “fractional exponents.” IIRC, he showed that the revolutions of the celestial spheres would never quite reproduce themselves because their periods were incommensurate.

    • He claimed that the ratio of planetary orbits were probably incommensurable and therefore there could be no repetitions but he never actually demonstrated the truth of his claim, which is by the way incorrect.

      • Hmm? He’s incorrect how? The system is essentially chaotic. Under either a purely Newtonian system or a purely relativistic system they will never repeat with probability 1. Am I missing something here?

      • Sorry very sloppy answer. In so far as the solar system orbits are almost certainly incommensuable Oresme is correct but as a criticism of the astrology of his times it doesn’t work. For astrologers the position a planet is determined by which star sign or house it’s in that’s a 30° chunk of the celestial sphere and not a specific point in space so conjunction, oppositions ect do repeat.

        The intertubes would probably call Oresme’s argument a strawman 😉

  3. Simplicio

    Interesting post.

    Calling Ptolemy “Ptolemaeus” is kinda annoying though. You did the same thing in an earlier post where the context was less clear and I spent a few minutes wondering who this ancient astronomer I’d never heard of was.

    • His name in transliteration is actually Ptolemaeos the ‘us’ ending is the Latin version. Ptolemy is a rather incorrect Anglicised version of his name.

      • Simplicio

        Yea, I figure it was due to some improved transliteration (though he was Greek and wrote in Greek, why care what the Latin version of his name would be?). But Ptolemy seems to have been the standard way to write his name for a considerable time, abandoning it now seems to cost a high price in comprehensibility for a pretty minor gain in linguistic correctness.

        I’m told Joshua is a much better rendering of the Hebrew name for the founder of Christianity, but if I start using that name for Jesus, no ones going to know what I’m talking about.

      • The use of the Latin ending is because since the Middle Ages Greek philosophy has always been dicussed in Latin. As to changes in terminology it’s just a question of being historically correct. I also don’t call Ibn al Haytham Alhazen!

      • Mike

        IIRC, the case endings were already vanishing in Late Latin, so Ptolemaeus was becoming Ptolemae in common speech; hence, Ptolemy.

  4. Rebekah Higgitt

    Thanks for this rip-roaring ride through the history of science! Two points I’m wondering about, though. I had understood that the early Christian Church actually borrowed a lot of symbolism from astrology, as they had from other mythologies. This would suggest that, even if somewhat fallen from elite culture, it was still important to many of the people that the church was trying to reach.

    The other thing is the fall of Aristotle and the rise of the new philosophy. Why exactly was going on here? Are we talking about empiricism or a rejection of tradition? As you say, thinking about all the different national contexts might help unpack what could be a rather sweeping statement (fair enough in a post that covers several centuries!).

    I’d love to look more on the late-19thc revival. This book was very useful and interesting, but I’ve not had much of a chance to follow it up further.

  5. astrologerthe

    “In 1586 things took a positive turn for the worse, when Sixtus V, elected to the papal chair on the death of Gregory XIII (not unsympathetic to astrology), enacted a bull against those practising judicial astrology, or even possessing books on the subject… more

    I guess most fled to the USA before being persecuted, afraid. Probably returning later after USA civil war. Also fortune telling is forbidden according to some Muslims Koran interpretation, can lose your head for that, even today!

    I liked the “Rise & Fall”
    However you should mention that Astrology continued to flourish in the East & Asia, why? “Because it works”
    – I believe many people fear that

    • This isn’t the time or place to debate the merits of astrology (although I will say that your repeated attempts whenever you comment to claim that it works wears a bit thin.) Instead I’m going to focus on two more narrow issue: First, what evidence do you have that *any* astrologers fled to North America (which is I assume what you mean by the USA given that 1586 is over a 150 years before the founding of the US). Second, what evidence do you have that people then returned after the US Civil War?

      • Illuminating and interesting summary, Thony C.!

        To the idea that this isn’t the time and place to discuss astrology’s validity: Actually Josh and Thony C., I find that the validity of astrology is pretty central to the history you’ve briefed us in throughout this post. Other factors like politics and fashion come into play, but throughout the post, there’s an undercurrent of astrology’s failure to provide any support for itself.

        If it actually worked, instead of being the result of confirmation bias and a sense of conquering the mystery of the night, I doubt it would be pressed into being a trend.

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  7. Glendon, while the trend nature of astrology is evidence for its lack of validity, it isn’t strong evidence. In many areas of science and learning, things come and go out of fashion without much connection to whether or not they are valid in a deeper sense. Thus, for example, in my own field (math) classical geometry went out of a favor for a very long time before Coxeter brought it back in favor. To use another example, from biology, in species classification, different approaches have gone in and out of favor. Finally, in linguistics, degree of acceptance of Sapir-Whorf seems to vary a lot by time period.

    Overall, the presence of something being trendy or even going in and out of favor is not very good evidence for the nature of the discipline.

  8. Will Thomas

    …the evil vizier of Hollywood film…

    Thony, in your email to me you mentioned that my thinking about 20th-century expertise caught your attention, because you were mulling over early-modern expertise. Your off-hand comment here actually gets at something that I’ve been having issues with, which is a widespread historical interest in taking attention off of the thinking of actual authorities, and putting it onto their advisers.

    As near as I can tell, this move seems to be made so that what is implicated in policy disasters is not simply a bad policy choice, but the introduction of fully rotten idea systems into the political process. On my end, one gets this for Cold War liberal thinkers: Halberstam’s Best and the Brightest set the tone early, but the idea of this having a connection to mysticism finds explicit resonance in titles like Fred Kaplan’s Wizards of Armageddon and Bruce Kuklick’s Blind Oracles.

    Anyway, I would be very much interested in tracing the long-term history of the polemics against advisers whose connections to mysticism/intellectual delusion are taken to undermine what I gather is taken as the inherent virtue of a political system.

  9. DiscoveredJoys

    I’m always reluctant to propose a single cause for any historical event, but I’ll suggest that the Great Pestilence (the Black Death) and the subsequent waves of further plagues all had some effect in revealing the impotence of magical thinking and manipulation of the world.

    When up to half the population dies and no-one can convincingly explain why, or what might be done to prevent it, that has to have an effect on people’s views. Arguably the Great Pestilence was one of the early links in the chain of events that eventually led to the loss of authority of the Roman Catholic Church and the magical thinking behind alchemy and astrology.

    • While the Black Death was possibly disruptive to the Church’s authority I have trouble seeing how that sort of thing would cause a general reduction in magical thinking. I’d guess that if anything the opposite would occur: subject to a frightening set of events with no apparent pattern humans will become more desperate and turn to things like magical thinking even more.

    • The timing is off. The plague hit in the middle of the 14th Century. The Reformation began in the beginning of the 16th. Alchemy, astrology, and magic flourished during the period between. The Middle Ages were an era of rationalism compared to what came immediately afterwards–if you compare the early Scholastics or Aquinas with later theologians and philosophers the contrast is quite striking. Great outbreaks of superstition such as the witch craze are a feature of the Renaissance.

      In any case, I think the evidence rather indicates that inexplicable disasters promote magical thinking.

      I’ve thought for some time that one explanation of why the occult lost some of its allure, at least among the educated, is the advent of printing. Before printing, one could maintain the illusion that great secrets were to be found in various old books precisely because it was so hard to come by these texts. After 1500 or so, everything was in print and fairly well off people could get their hands on the works of the Thrice Great Hermes and wagons full of other stuff. Mystical lore became something of a drug on the market while scientific knowledge kept some of its prestige because its secrets were protected not by spells or secrecy but by the intellectual difficulty of the subject. No master of quantum field theory has to take a vow to reserve his equations to a handful of worthy acolytes. That kinda takes care of itself.

      • Discoveredjoys, as usual Jim H. is correct. The Black Death decimated the population of Middle Europe in the 14th century. During this period the attendance at the European unitversities and the graduation rates fell drastically. It was during the recovery of tertiary education at the end of the century that the occult science, natural magic, astrology and alchemy, entered the universities on a wave of hermeticism, neo-Platonism and humanism. These occult science remained a central element of the European intellectual milieu until well into the 17th century.

      • DiscoveredJoys

        I see I did not put my case clearly. Yes, the original wave of the Great Pestilence worked its way across Europe in 1340/1350s. Up to this time religious ceremony and ritual was deeply embedded in ordinary life. Most ordinary people believed absolutely that without the right prayers and ceremonies their soul would not go to heaven. This belief (religious magical thinking) was shattered by the first wave of the Great Pestilence.

        The poor harvests and heavily reduced population following the first wave of plague broke the strong sense of community and reliance on authority and social order.

        This was the beginning of the many other changes that led to the reformation – but of course that took much lomger than we would expect from our modern experience of the speed of social change. The population didn’t recover for 150 years, and there were further outbreaks of plague over the next 3 centuries.

        Arguably the Great Pestilence paused the new scholarship which had arisen and been confined to religious orders prior to the plague. Certainly when the scholarship restarted it started with a new worldview.

      • DJ, at the top righthand corner of this blog is a quote from John Wilkins that basically says if your theory of history doesn’t fit the fact then your theory is wrong. Both Jim H. and I have pointed out to you that your theory doesn’t fit the facts so I don’t quite understand why you come back and repeat the same thing even more assertively.

        The two centuries following the great plague in the 14th century were the period of greatest belief in all things occult, spiritual and mega woo in the whole of European history a fact that totally contradicts your whole theory.

        In general, and what follows in purely subjective, in my experience doom and desaster tends for some perverse reason that is totally beyond my comprehension to increase peoples belief in religion and the occult and not weaken it.

    • DiscoveredJoys

      Sheesh, it appears that some people think I’m trying to redefine historical events. Not so.

      I was putting forward an opinion that without the Great Pestilence and subsequent breakdown in social order the attempts to form a new understanding of the world would have been delayed considerably. Scholars still had to go through the works of the ancients in search for the new understanding.

      Those first attempts were a different form of ‘magic’ and led in turn to the Reformation and later the Enlightenment, undeniably true. But I suggest that without the certainty of the church being loosened those changes would have been delayed considerably more.

  10. astrologerthe

    Comment deleted by moderator because deliberately insulting to other commentators

    • thonyc

      astrologerthe, did your stars warn you that today would be a bad day in the Internet for you?

      Congratualtions, you’re the first person to get banned at The Renaissance Mathematicus. I warned you not to insult other commentators, apparently my warning doesn’t interest you. That being the case your comments no longer interest me and will not be tolerated here any longer. Bye, bye!

  11. Per Ove

    That Galileo routinely taught Astro 101 during his tenure as professor for mathematics in Padua might not be good evidence that he also believed in astrology; most of his time in Padua he believed in heliocentrism, but it seems that he taught geocentrism during and not heliocentrism in Padua.

    That he was a practicing astrologer might maybe not be very good evidence either, to me it seems that he tried to make money as often as he could.

    But if there really is pretty good evidence that Galileo believed in astrology, that is very interesing.

    Btw, there is an uncommented request here

    • Rebekah Higgitt

      You might as well claim that his teaching and research in astronomy and mechanics are no proof that he believed in them, for they too were means of earning money and gaining noteriety or patronage.

      It’s interesting that Galileo calculated his own horoscope, and those of his daughters, which would not immediately appear to be something you would do just to please a patron.

      • Per Ove

        “It’s interesting that Galileo calculated his own horoscope, and those of his daughters, which would not immediately appear to be something you would do just to please a patron.”

        Yeah, I agree, that’s a pretty good argument. And as always, I do take references to litterature.

    • Thank you Ms Higgitts Higgitt you saved me having to say the same thing.

      Ove I assume you mean you would like a reference, for the moment J. L. Heilbron Galileo pp 90ff.

      Somewhere I have a paper on Galileo’s activities as an astrologer if I find it I’ll send you the details!

      • Per Ove

        Thank you. A copy at the University is reserved.

      • Rebekah Higgitt

        *Dr*, if you please! 😉

      • Although I live in Germany where anybody with a doctor title insists on being called “DOCTOR” I belong to the generation of Englishmen for whom only medical practitioners were addressed as “doctor” and all others are plain Mr or Ms (yes I’m a feminist). I take my cue from Bertrand Arthur William 3rd Earl Russell who was Mr Russell to strangers and Bertie to his friends!

  12. Nick Kollerstrom, Galileo’s astrology in Jóse Montesinos and Carlos Solís (eds.), Largo campo de filosofare: Eurosymposium Galileo 2001 La Orotova: Fundción canaria Orotava de historia de la ciencia, 2001 pp 421 – 431.

    • Per Ove

      Thank you. But according to Wikipedia, Kollerstrom has been involved in Holocaust denial controversy. Even though Galileo & astrology is less controversial, why should he be trusted in this matter.
      Always searching for the best sources, Per.

      • What ever Nick Kollerstrom might or might not have said or written about the Holocaust he is a recognised authority on the history of astrology and his paper is considered the standard account of Galileo’s work as astrologer. He is also together with Nick Campion the editor of Galileo’s astrological papers. Galileo’s Astrology, Ed. Nicolas Campion and Nick Kollerstrom, Culture and Cosmos, 7:1(2003).

  13. Nice article Thony. Wish I had more time to comment but work-pressure is too full-on at the moment. Just thought I would add a link to a page which shows some of Galileo’s workings on his horoscope. There is a link in the page to articles by Nick Kollerstrom about Galileo’s astrology, and other connected links to more relevant material if anyone is interested. As you say, the proof that Galileo was not just ‘doing it for the money’ is that he was doing his own family charts. This is also the case with Kepler who also gets written off as ‘just doing it because he was forced to’ – but we know this is not true because of the very personal family charts he did and which he wrote about and discussed in his letters to his close friends. Anyway, the link to Galielo’s worksheet on his own chart is here:

    PS – I also made a list of links to this and several other astrology-related blog posts which have been published lately at

    I am trying to keep a record because some of the material (such as yours) makes very interesting reference material.

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