A couple of post ago. I mentioned Thony C’s post on the place of Galileo’s Dialogo within a whole range of what I intentionally called “astronomical-cosmological” ideas. Thony presented Galileo as being somewhat disingenuous about the number of competing systems that astronomers were then considering and those systems’ relative status in contemporaneous astronomical thought. The implication is that the only thing going on in the Dialogo was a sort of popularization of that thought. What Thony knows but left unsaid was that astronomers were not the sole players in the cosmology game in the early 17th century. [my emphasis]
I have quoted this passage not because I feel flattered by Will’s attention to my scribblelings, which I do, but because he makes an important point that I wish to illustrate with an example. All of players in the 17th century cosmology game were religious believers, some like Kepler can even be described as religious fanatics, and theological considerations played a significant role in their schemes, as I have recently noted for Kepler. As I have commented in the past the truth hierarchy in the 17th century placed theology at the top above natural philosophy with mathematical astronomy at the bottom. This meant that theological considerations on cosmology could and did exercise a strong, and at times positive, influence on the development of the new cosmology in the 17th century. The example that I am going to bring is from that supposed enemy of science Roberto Bellarmino but first I need to set up the background.
In Aristotle’s cosmology the planets and the stars are carried round the heavens on a clockwork of nested solid crystalline spheres that function through a sort of friction drive the outermost sphere being moved by the unmoved mover. In the synthesis of Aristotle’s philosophy and Christian theology that Albertus Magnus created in the 13th century Aristotle’s unmoved mover became the Christian God and so the crystalline spheres became a constituent part of mediaeval cosmology. Now it is clear that the crystalline spheres were something that had to be disposed of in the Early Modern Period on the long drive to the modern astronomy and cosmology.
In the standard astronomical/scientific revolution mythology the dispersal of the spheres was the brilliant (heroic!) achievement of one giant of science Tycho Brahe who proved that the great comet of 1577 was above the moon and not below it as claimed by Aristotle and would therefore destroy the spheres on its flight and so these could not exist. As usual in the history of astronomy the real story is much more complex and involved various differing factors. Firstly, that comets were supra-lunar (above the moon) and not sub-lunar (below the moon) had been being discussed by the leading European astronomers since a series of spectacular comets in the 1530s. Several of them including Fracastoro, Cardano, Jean Pena and Gemma Frisius were already claiming that comets were in fact supra-lunar this was the reason why Tycho and many other astronomers tried to measure the parallax of the comet in 1577. The results were contradictory and inconclusive but several leading observers including Tycho and Michael Mästlin (Kepler’s teacher) concluded that the comet was supra-lunar and in the end their view prevailed.
One of the reasons for this 16th century debate was the renaissance of Stoic natural philosophy. Because of the dominance of Aristotelian natural philosophy in the High Middle Ages people tend to forget that it was only one of several competing philosophies in antiquity and that in fact in the later part of this period the natural philosophy of the Stoics was more dominant than that of Aristotle. Unlike Aristotle the Stoics did not differentiate between the sub-lunar and the supra-lunar spheres the whole universe being the same and permeated with pneuma and there being no crystalline spheres. In Stoic cosmology comets were also supra-lunar. As already mentioned there was a Stoic renaissance in the 16th century, which had a strong influence on the cosmological debate.
We now turn to Bellarmino and the part that he played in the dissolution of the spheres. In the 16th century there was no actual agreement as to how many spheres there were. Depending on ones cosmological theories there were eight, nine or ten celestial orbs, as they were known. In fact one of Copernicus’ three known astronomical manuscripts is the so-called Werner letter in which he attacks the theories on just this topic of the Nuremberger mathematicus Johannes Werner. Now it was common practice to equate a celestial orb with a heaven so it was thought that there were eight, nine or ten heavens. As a young man Bellarmino taught at the University of Leuven and amongst other things he lectured on cosmology. Bellarmino argued on theological grounds that the Bible and the patristic literature, the bedrock of Catholic theology, only mention three heavens and therefore the crystalline spheres could not exist and were a fiction. Instead he proposed that the heavens were liquid and that the planets swam through them like fish through water; this theory was held not only by Bellarmino.
By the beginning of the 17th century Bellarmino had become the most important and influential theologian in the Catholic church so Catholic astronomers and especially those who like Bellarmino were Jesuits, and it should be remembered that Jesuit astronomers made an enormous contribution to the development of the new astronomy, were quite happy to refer to Bellarmino’s lectures in order to dump the whole apparatus of Aristotle’s crystalline spheres. Removing the crystalline sphere had of course massive consequences for astronomy and cosmology. Without the whole clockwork friction drive of the spheres to explain the movement of the planets astronomers were forced to find an alternative explanation a search that would eventually lead to the theory of gravity.
Should any reader be tempted to think that my example of theological cosmology positively effecting the development of science is a singularity and thereby unique I would urge them to think again, all of Kepler’s work was driven by his theological convictions and the Clarke-Leibniz correspondence which contains the first scientific debate on relativity contra absolute time and space was also in the first instance a theological debate. There are also other examples. It should also be pointed out that my brief post by no means covers all of the positions and arguments generated by the debate on the existence of the crystalline spheres in the Early Modern Period and anybody who is interested in learning the whole story should read William Donahue’s The Dissolution of the Celestial Spheres 1595 – 1650, New York, 1981.
1) Stephan Toulmin as a philosopher and Toulmin and June Goodfield (his wife) as historians had a strong influence on my own development as a historian of science so I was pleased to see Will acknowledging the first anniversary of his death with his post.