Concerning the vanity of astrology
Abstract -- Unlike modern scientists, most of whom have little knowledge of astrology, John Flamsteed (1646-1719), the first astronomer royal, was well acquainted with astrology, its literature, and astrologers. His criticism was based on several years of personal experience in reading charts and putting astrology to the test, and is thus of some interest. His points (the disagreement on basics, the endless nonfalsifiability, the absence of a mechanism) still apply today. Flamsteed's 1674 writing style is necessarily archaic and wordy, so his criticism has been condensed using a more modern style to just under 25% of its length.
Perhaps the earliest criticism of astrology by a major scientist was written in the 1670s by John Flamsteed (1646-1719), the first English astronomer royal for whom Charles II built an observatory at Greenwich (in 1675) where he worked for 44 years. Flamsteed was well acquainted with astrology, its literature, and astrologers, and his criticism reflected several years of personal experience in reading charts and putting astrology to the test. What follows is based on M.Hunter, Science and Astrology in Seventeenth Century England: An Unpublished Polemic by John Flamsteed, in P.Curry (ed), Astrology Science and Society: Historical Essays, Boydell Press, 1987, pages 261-300.
In his autobiography Flamsteed tells how in 1665 (when he was 19) he busied himself "calculating the nativities of several of my friends and acquaintance", and how in 1666 he "spent some part of my time in astrological studies" that led to him finding "astrology to give generally strong conjectural hints, not perfect declarations". His criticism of astrology appeared not in his autobiography but in the preface to a draft ephemeris for 1674 that he had compiled as a reaction against the (in his view) debasing of astronomy then being published as part of astrological almanacs.
He explains his view in a letter to a cousin: "I am vexed to see our Ephemeridists spend the pages of their almanacs in astrological whimseys tending only to abuse the people and disturb the public with anxious and jealous predictions, whilst the prediction of celestial appearances which ought to be their only concern is wholly scorned or neglected". But no publisher could be found for such an ephemeris, let alone one containing a criticism of astrology (which in popular form was an essential part of any almanac if it was to sell), and only one copy of the draft manuscript survives.
Flamsteed's preface runs to more then 3700 words. Its 17th century spelling, phrasing, now-obsolete words, and verbose style make it heavy going, so it has been condensed here using a more modern style to just under 25% of its length. Interestingly, the arguments raised by Flamsteed against astrology are much the same as the famous Disputationes adversus astrologiam raised by Pico della Mirandola in 1495, and just as interestingly they still apply today, namely the disagreement on basics, the endless nonfalsifiability, and the absence of a mechanism by which astrology could work. Today only the use of statistics and computers has enabled us to significantly better his conclusions.
A preface on the vanity of astrology and astrological practice
At first I thought the fault might lie in the arcs of direction, which differed according to author (eg Ptolemy, Kepler, Naibod). So I tried them all very carefully on ten charts and found that none of them worked accurately. This made me doubt sometimes the charts, more often my own skill, but rarely the authors or astrology. So I checked again the various books, and found great differences (eg in rulerships) between our astrologers and the Arabian professors. This made me cautious.
I soon found that when astrologers found no direction in a corrected chart to match a notable accident, they referred to other indications such as that year's revolution, seizing on whatever could be made to match the accident despite better arguments to the contrary. And that when they proclaimed the truth of their predictions, they ignored any aspects, directions or transits that failed to show accidents.
Also, if the case could not fairly be proved, they pointed to defects in their ability, or to needing more time to consult their books, rather than acknowledge the least error in astrology. But it is a miracle if the case cannot be proved, because astrologers have so many rules, and so many aspects, transits, directions, revolutions, and progressions to consider, and so many ways of considering them, that it is impossible not to find something that matches the event even though it is hard to see why the contrary indications should be overpowered. But if even that approach fails, they say that God has overruled the stars.
These failures were one of the reasons that caused me to stop studying astrology and reject it as false. A more important reason was the absence of any way that the planets could influence our actions and thoughts. Thus it was impossible to see how their rays meeting in trine or quartile should be either beneficial or harmful; or how the sun could be more strong in one part of the heavens than another; my experience is that persons with well-placed planets do not attain more than those with ill-placed planets. Also, astrological predictions of the weather are no less ridiculous, for the aspects on which they are based apply as much to Egypt or America as they do to Engand. Indeed, so small is the verity of astrology that even astrologers do not agree on where it lies. Thus William Ramsey (Astrologia Restaurata 1653) says it lies with elections while William Lilly (Christian Astrology 1647) says it lies with horary (he makes his living by them), but John Gadbury (Genethlialogia 1658) laughs at both, thinks that elections are a vanity and horary uncertain, and says it lies with nativities, which I can disprove with one of his own examples of a famous person where, if the name of the person were concealed, the chart would be judged as indicating an idiot rather than a famous person.
Mr Gadbury's cunning in covering the faults of his art is superlative. Most of his charts are of deceased persons, in which having chosen a birth time giving directions for the most notable accidents, he counts this with no little pomp as mightily pronouncing the truth of astrology, all the while concealing how much his corrected time differs from the observed time. But he is more sparing of his predictions for living persons lest the event not occur, and with good reason -- he predicted danger of death in 1661 for the King of Sweden (or 1663 if he should escape 1661), certain death in 1660 for the Prince of Orange, and the same in 1667 for the Duke of York, yet today (1674) all three are still alive and well.
Even if we grant the planets some influence, we must still ask how astrologers can be confident of their judgements when they do not agree on which house system to use, nor on how to use fixed stars. They agree that the stars do have an influence, and some pretend to use them when everything else fails, but they never consider their aspects, which may contradict what is promised by planetary aspects. So how can we be certain of the truth of their predictions?
And tell me, reader, how it is possible that the planets, reflecting only a small part of the sun's light, should have more effect on us than a good fire or candle, which despite their superior light and heat have not the influence on our thoughts and actions that the astrologer says comes from the stars.
Since astrology finds no natural grounds to sustain it, and since experience shows us its falsehood, I hope my readers will withdraw any credit they may have given to this imposture. As for astrologers, I have no hope of reforming them because their profession -- no matter how foolish and opposite to reason -- is too lucrative. My reward for this plain speaking will no doubt be the title of "ignorant and peevish".