Thursday, 26 February 2015

Astronomy vs. Astrology: Science vs. Superstition in the 18th Century

It's a pleasure to welcome Monica Hall to the blog once again with a post on astronomy versus astrology... 


Science vs. Superstition in the 18th Century

The 18th century is acknowledged to be the beginning of ‘big’ science in many areas – chemistry, physics, biology, mathematics etc. It was also an era of improving optics thanks originally to Newton’s reflecting telescope.  Great minds included Edmund Halley (1656-1742), who followed in the footsteps of Johannes Kepler (1571-1630), and devoted much effort to coordinating the extraordinary opportunity for astronomers to observe two transits of Venus during the 18th century, in 1761 and 1769, which he never saw.  Halley had calculated the dates of these event in 1716, and warned fellow scientists that it would not happen again for a century, so they had plenty of time to plan for this unmissable opportunity to calculate the size of the solar system.  This was definitely big science, at a time when accurate map-making here on earth was in its infancy.  It took over 200 worldwide observers of the transits to provide the data from both events to calculate the distance from Venus to the Sun, and then to extrapolate the size of the solar system from Kepler’s calculations of the orbits of the other planets.  This was a huge achievement, and their accuracy was not exceeded until the 20thC, and then not by so much.  

Used as we now are to stupendous distances in space and time, it is difficult to imagine how astounding these calculations were.  And to compound the mystery was the Milky Way, also an object of intense observation and curiosity in the 18th century.  The works of William Herschel (1738-1822) and Thomas Wright (1711-1786) convinced other scientists that it was a flattened disc comprising untold suns similar to ours, the stars in the galaxy.  Below is Herschel’s ‘Universe’ (Milky Way) with our sun at the centre-left, naturally, but Wright spotted faint nebulae much farther away which he (correctly) thought were other galaxies.  Cue religious tremors.

The rather odd notion that our lives might be influenced by the stars has persisted, it seems, since time immemorial.  Without very much knowledge about such things as radiation or gravity, even during the exploding Enlightenment, people thought that the Heavens exerted a power, which it obviously does, but hardly extending to whether it is a good day to wage war, ask your boss for a raise, or invest in the South Sea Bubble (burst 1720).

Prognostication has always been good business, from the Oracles onwards that we actually know about, but surely long before that.  Croesus allegedly consulted the Delphic Oracle before waging war on the Persians, and was told that a great empire would fall (the Oracle was taking no chances, as usual).  Croesus optimistically assumed it would be the opposition’s empire, but sadly it was his.  One would think this might have put a crimp in the Oracle’s reputation, but everybody just blamed Croesus.  

The progress of the Enlightenment during the 18th century did put a crimp into belief in astrology.  It was still very popular, however, as it had been in previous centuries, despite Church disapproval and associations with witchcraft and, weirdly, the credulous had to be educated; they had to be literate in order to read the Almanacs and pamphlets.   One such writer was John Partridge who was born the son of a shoemaker in Covent Garden, but who educated himself to the degree necessary to study medicine in Holland.  He also believed in astrology, and wrote assiduously of the need to return to the Ptolemaic system of interpretation, instead of the Arabic, and broadcast his views.  This sort of conflict between science and what we would call superstition was not uncommon in the 17th/18th centuries.  Newton, himself, apparently spent an inordinate time on alchemy, and rather less on gravity, optics, and mathematics.  

Others, however, were rather more sceptical.  Jonathon Swift (1667-1745) sharpened his satirical quill and created the fictional ‘astrologer’ Isaac Bickerstaff Esq., which was a direct attack upon Partridge, but not quite why you might expect.  Swift was devout, whereas Partridge was not, so both these educated men attacked each other’s supernatural beliefs.  Swift’s most successful spoof was Bickerstaff’s prediction of the death of Partridge by a ‘raging fever’, which dogged the latter until his actual death.

Here, five Foot deep, lies on his Back,
A Cobler, Starmonger, and Quack;
Who to the Stars in pure Good–will,
Does to his best look upward still.
Weep all you Customers that use
His Pills, his Almanacks, or Shoes;

Before Swift, in the 17th century, an unknown genius created Poor Robin’s Prophecies.  This was a savage satire on almanacs and religion, lampooning astrological forecasts by predicting the totally obvious, and creating bogus saints’ days.  It sounds fun.  It is alleged to have lost its sharpest satirical edge by the early 18th century, but nonetheless gained an international reputation for parody, being published in the USA as well as here, and lasting until 1776.  An appreciative commentator remarked that the Prophesies were enough, for men and women of sense, to ‘break their twatling-strings’.  Sadly, we do not seem to know what these were.  I, for one, want to.  

But before you come over all 21st century, read this extract from the Independent (24.10.05) about one of our world’s most successful astrologers, Jonathan Cainer.

He claims a vast army of "at least 12 million people" who devour his planetary musings in various forms - syndicated newspaper columns, books, phonelines and the net. Small wonder then that his worldwide businesses turn over £2m annually and employ 30 staff. There's little doubt why newspapers fight for his services. "Horoscopes," he says, "have turned out to sell papers, just like the cartoon, the sudoku or crosswords. They are a little bit of reader glue. And a good astrologer will do two things for a newspaper: bring in new people and keep the ones you've already got because it becomes a matter of familiarity."

But the last words on this subject should be from one who was there at the time, and not avidly reading an Almanac to discover what the stars held in terms of romance, finances and fate, but a true scientist. 

It is said that Kepler’s belief in astrology informed his entire scientific career, so one cannot simply write off such beliefs as mere superstition.  They were understandable in their time but, more importantly, became a springboard of curiosity from which we have so benefited.


Patrick Curry, Prophecy and Power: Astrology in Early Modern England, (Cambridge: Polity Press, 1989) 
Wardhaugh, B. (2012), Poor Robin’s Prophecies:  A curious Almanac, and the everyday mathematics of Georgian Britain, OUP

About the Author

Retired after a working life in business and management, Monica thankfully pursues her interest in both philosophy and the history of our Industrial Revolution.

Written content of this post copyright © Monica Hall, 2015.


  1. I believe the 'twatling strings' are the groinal muscles, and breaking them would be what today we call a groin strain. I've heard it in context of physical strain, but it might also be in context of laughing too much.

  2. Thank you, Sarah. I knew it must be something down there ...