As has become tradition at the Renaissance Mathematicus today’s post is dedicated to our favourite scientist Johannes Kepler who was born 27th December 1571. It is a little known fact even amongst historian of science but Kepler was involved in a somewhat unseemly dispute with the English alchemist Robert Fludd and I shall now take a look at this quarrel and also at how it has often been perceived.
Fludd was a Paracelsian physician who after graduating at Oxford spent six years travelling and studying on the Continent before settling in London in the first decade of the seventeenth century. He quietly and successfully ran his medical practice attracting no further attention until the Fama Fraternitatis appeared in 1614. This was one of a series of anonymous publications describing the Rosicrucian Brotherhood a secret community of alchemists. At the time opinion was divided as to whether the Brotherhood really existed or whether the whole thing was just an elaborate hoax. Fludd a practitioner and defender of the Paracelsian alchemical medicine believed in the existence of the brotherhood and in 1616 he published a pamphlet defending them against their detractors. Starting in 1617 he then proceeded to publish a series of richly illustrated large format volumes putting forward his own mystical alchemical theories of the natural world. Fludd’s philosophy was based on a Paracelsian micro-cosmos macro-cosmos theory and he interpreted the world in terms of a series of highly complex mystical diagrams rather like Buddhist mandalas. He believed that one could only approach the true essence of nature through such symbolic representations and he explicitly rejected the then emerging mathematical description of the physical world. Central to Fludd picture of the world was the so-called Pythagorean mono-cord, an instrument that displayed the numerical harmonies of Pythagorean philosophy. (I’m not even going to attempt to go further in describing Fludd’s philosophy of nature and if anyone wants to know more go ask Ted Hand!)
Fludd’s Pythagorean Monocord
In 1619 Kepler published his magnum opus the Harmonices Mundi and in an appendix he launched a vicious attack on Fludd and his theories, rejecting them as absurd. Kepler’s motivation is fairly obvious as his own world system, wholly mathematical, which he had presented in great detail in his book, was like Fludd’s based on Pythagorean harmony theory.
Kepler’s Geometrical Model of the Planets
Fludd, probably glad of the attention he was receiving from one of Europe’s leading mathematical astronomers, responded with a pamphlet attacking Kepler that did not spare the invective. He accused Kepler of crass ignorance calling him one of the vulgar mathematicians who are bastards and stunted people. He thinks that the mathematical description of nature propagated by Kepler and his ilk only touch the outward appearances of things and do not reveal their true essences. He goes on to claim that only the chemical philosophy of which he of course is a practitioner can reveal the true picture of the world. (Again I shall refrain for going deeper as it is not really relevant to what I want to say in this post.) Kepler never one to run away from an intellectual punch up responded in turn with his own invective laden pamphlet, which of course provoked another salvo from Fludd. At this point Kepler declared himself tired of the whole affair and the dispute fizzled out. What is interesting for the modern historian is how this dispute is interpreted.
For Max Caspar who wrote the first, and until today, most extensive modern academic biography of Kepler it is obvious that Fludd is a woo master and Kepler the modern scientist or as he expresses it, “ …Kepler has drawn a sharp line of distinction between his world of thought and the occult literature of his time”. Of course in making this claim Caspar ignores the fact that Kepler’s original attack on Fludd was made in a book that although thoroughly mathematical, and containing possibly his greatest contribution to mathematical astronomy his third law, is in fact about ninety per cent occult woo. Frances Yates who as an expert for all things Hermetic including the Rosicrucian Brotherhood and Robert Fludd, in her Rosicrucian Enlightenment sees Kepler as, “…deeply immersed in Hermetic influence … and one could almost call him a heretic from Rosicrucianism”. The person who probably judged the situation best was Arthur Koestler who gave his biography of Kepler the title The Watershed to indicate the fact that Kepler stood with one leg in the past and one in the future. The same could also be said of Fludd and almost all of the Renaissance natural philosophers.
Both Kepler and Fludd were deeply religious Christians and both of them were convinced that they were delivering the world a Christian science. Kepler saw his work as revealing God’s geometrical plan of the world and believed for example that the world (solar system) was finite because the sun was God the Father, the sphere of the fixed stars was Jesus and the space in between the Holy Ghost. Fludd believed that like Paracelsus he was developing a Christian medicine based on interpreting the Bible to replace the heathen medicine of Hippocrates and Galen. Both developed an archaic mysterious metaphysics to explain their work but both made serious contributions to the future of science, as we understand it. The contributions of Kepler are well known and I don’t need to repeat them here but what of Fludd? Historians of medicine and alchemy have long ago demonstrated that Paracelsian medicine, although in terms of healing craft no improvement, helped to pave the way away from the humoral medicine of antiquity to modern scientific medicine and that the Paracelsian chemists laid the foundations for both chemical pharmacology and chemistry. Fludd was the leading Paracelsian physician in Britain in the first half of the seventeenth century. Fludd was also an independent co-inventor of the thermoscope the predecessor of the thermometer. Lastly Fludd was a close friend and colleague of William Harvey and was the first to accept and publicly support Harvey theory of the blood circulation. He even helped Harvey to get his De mortu cordis published by his printers in Germany. Of course Fludd’s contributions to the history of science cannot be compared to the immeasurably greater contributions of Kepler but they are enough to say that he also had a foot in the future.
In reality to judge either Kepler or Fludd as a woo master or a modern scientist is an example of presentism and one should view both of them as what they were, a product of their time Renaissance thinkers.