 Hi, I'm Peter Adamson, and you're listening to the History of Philosophy podcast, brought to you with the support of the philosophy department at King's College London and the LMU in Munich, online at historyofphilosophy.net. Today's episode, If This Be Magic, Let It Be an Art, John D. I suppose that most of you out there are listening to this because you are interested in philosophy, in history, or both. But there might just be a few who follow the podcast in hopes of getting inspiration for a new movie script. If you're one of that select group, then today's episode is for you, because our subject is the mathematician, alchemist, astrologer, magician, and philosopher, John D. Amazingly, his life has never been made into a film, though there is a documentary about him, and he has a walk-on role in that movie where Cate Blanchett played Queen Elizabeth. Yet the Hollywood pitch almost writes itself. Here we have a man who met or communicated with many of the most significant figures of the Elizabethan age, like Philip Sidney, Peter Rames, Thomas Harriot, and the Queen herself. D was involved in Martin Frobisher's catastrophic attempt to find a Northwest passage to circumnavigate the globe. He invented the concept of a British empire. He produced horoscopes for the rich and powerful, and consulted with Elizabeth about astrology. Before she came to the throne under Queen Mary, he had been arrested for magic, but before long, hey presto, he was working for the Catholic government, helping interrogate other suspects. But he might have been a Protestant spy. He traveled across Europe, going as far as Poland, where he might have been a spy, again. Sorcery, exploration, intrigue, this story has it all, and I haven't even mentioned the fact that Angels gave him rather scandalous advice about his sex life. But, this podcast is not a sensationalist Hollywood movie. What follows will, of course, be a sober, nuanced discussion of D's thought, which will just happen to include sorcery, exploration, intrigue, and angelic, or possibly demonic, advice about sex. In fact, to forestall any accusations that my approach here will be in any way prurient, let's talk about the aspect of his career I personally find most exciting, his library. You may think I'm kidding, and that's because I am, but let me tell you, this was some library. It has been estimated to be the largest collection in the country at the time, with no fewer than 8,000 printed books and 1,000 manuscripts. It had many books on philosophy, from Aristotle and Plato to the Neoplatonists and the Pseudo-Dionysius, as well as Renaissance Platonists like Ficino. Science and mathematics were well represented, from Euclid to Paracelsus. In fact, D had more than 100 Paracelsan works, probably the largest number in England. Of course, he had books about alchemy and magic by authors like Trithemius and Cornelius Agrippa. There were many works on history, too, another of D's interests. As the Renaissance scholar Francis Yates once remarked, the whole Renaissance is in this library. Unfortunately, this wonderful collection does not survive complete today, as it was eventually ransacked while D was off in central Europe. But some volumes do survive, and D's annotations in these provide useful insight into his thought. The scope of the full original library is known through a catalogue that D himself had made. Many works were included multiple times, sometimes in different editions, Aristotle's treatises, for example, or Plato's Timaeus, of which he had four copies. This would have allowed philological work on the text, and also facilitated lending or resale. Euclid's Elements, a work of special interest to him, was represented in the library with no fewer than 20 printed copies and seven manuscripts. Alongside the annotations, another sign that these books were for use and not for show is that many of the books were unbound. The classification system, such as it was, would have meant that visitors needed D's help finding what they wanted. For example, books were partially arranged by size, in some cases arranged vertically along the shelf, and others piled up in stacks. But D did want visitors to use the books. He called his house at Morton Lake, not far from London, a hospice for wandering philosophers, and hosted and communicated with a wide variety of scholars. These included the aforementioned Ramus, Harriet, and Sidney. Sidney studied with D, whom he called our unknown god, and we have a horoscope that D cast for him. The connection to Ramus, with whom D corresponded about mathematics, suggests European connections, and this is not misleading. First educated at Cambridge, D went to Levan, where he met the scientist and doctor Gemma Frisios. Here too was Gerard Mercator, a significant figure in the history of cartography. He's the namesake of the style of world map called the Mercator projection. I mentioned this not just to convey the range of D's contacts, but because it foreshadows D's own later work on navigation, which was surely in part inspired by his time in Levan. He then made his way to Paris, where he lectured on Euclid with such success that, according to his own report at least, students were leaning through the windows from the outside to hear him. It was D's reputation as an expert in the mathematical sciences that won him access to the world of Elizabeth's court. Maintaining a large household which doubled as a workshop for natural philosophy, with instruments like mirrors and clocks as well as books, D was in constant need of money and patronage, which he sought from figures like Francis Walsingham and Elizabeth herself. We should also spare a thought for his long-suffering wife, Jane, who had to keep that household running with a constant stream of noble, learned, and, as we'll see shortly, deeply problematic guests. This is what it looked like to establish a late 16th century research institute like Tycho Brahe's Oraniborg, but without access to independent funds, like Brahe enjoyed. But D was not only trying to raise funds, he was also trying to influence policy. It was in this context that he proposed to the queen the notion of a British empire to compete with the international reach of Spain and Portugal. In a four-volume work called General and Rare Memorials Pertaining to the Perfect Art of Navigation, which, like his beloved library, survives only partially, D used his historical researches to support claims of royal entitlement to part of the New World. He pointed to fanciful stories about supposed British explorations from the distant past, like the Welsh king Madoc, who supposedly beat Columbus to America by 300 years. Actually, since quite a bit of D's thought looks rather fanciful to us today, and since this is what he tends to be remembered for, I think I should emphasize that he really did deserve his reputation for expertise in mathematics. He valued this discipline in part for its theoretical status, as we can see from one of his most well-known texts, the mathematical preface to an English translation of Euclid's Elements. Here he promises, I will frame my talk to Plato his fugitive scholars, or rather to such who can well use their outward senses. This is a doubly revealing passage. It shows his commitment to Platonism, in particular a Platonist approach to the mathematical disciplines, which are seen as offering an intermediate step between the physical and spiritual worlds. As D puts it, mathematical objects have a marvelous neutrality and strange participation between things supernatural, immortal, intellectual, simple, and indivisible, and things natural, mortal, compounded, and divisible. On the other hand, D's reference to the outward senses is telling because the preface also lays great stress on the role of empirical work in science. In keeping with this, D was keenly interested in applied as well as pure mathematics. This showed itself from the very beginning of his career. As a student at Cambridge, he deployed his knowledge of mechanics to build an animated scarab that featured in a student production of a play by Aristophanes. Later, he would impress Elizabeth by showing her a trick mirror. A mere novelty, perhaps, but one that shows how competence in optics could be used to win over a potential patron. And it doesn't get more practical than that. The same combination of theoretical and applied interest can be found in Thomas Digis, whom D trained as a mathematician after Digis's father died while Digis was still young. Digis called D his mathematical father and enthusiastically embraced the family business. He wrote on theoretical mathematics, as in a 1571 treatise on the platonic solids, which castigates those who cannot appreciate such discussions as two-footed moles and toads, whom destiny and nature hath ordained to crawl within the earth and suck upon the muck. On the practical side, he advised on engineering projects and a military expedition to the Netherlands in 1585. The newly emerging discipline of artillery ballistics could benefit from the expertise of such a man. And so could the would-be imperial project of navigation. D envisioned a discipline he called hydrography, which would chart the tides, coastlines, and dangers that could befall mariners upon the seas. Waxing enthusiastic, as usual, he said that his discussion of the principles of this art aimed to stir the imagination mathematical and to inform the practice mechanical. But for navigation, the most important discipline was again a mathematical one, namely astronomy. So it was D's knowledge of the heavens and their use in navigation that got him involved in the attempt to find the Northwest Passage. This was a failure, as you probably know. Frobisher returned with no news of the hoped-for passage, though he did have a kidnapped Inuit man and plenty of mineral ore. D was appointed Privy Council as a commissioner for the assaying of ore from the Northwest, which sounds good until I tell you that the ore contained almost no precious metal. His name suffered by association with the debacle, but the story should not take away from D's standing as an astronomer. For example, both he and Digas wrote treatises about the comet, or new star, of 1577. Though these were independent texts, they were often published bound together. In these writings, the two men explored the phenomenon of parallax, which we talked about when looking at Copernican and post-Copernican astronomy in central Europe. While they had a shared understanding of the mathematics involved, their interests in the topic were strikingly different. Digas was among the first Englishmen, if not the first, to lend explicit support to Copernicus's heliocentrism. For him, the comet was interesting because it proved that the heavens beyond the moon were not unchanging, as claimed by Aristotelian cosmology. As he wrote, echoing D's link between mathematics and Plato, whoever wears these platonic, or to use a more accurate expression, mathematical wings, and heads upwards into the ethereal realm, leaving behind entirely the elemental regions, will see that the new star is much further away. But for D, parallax was of interest because it can be used to measure the distance of astronomical bodies in general, including the usual planets. And here we come to the parts of his natural philosophy that may seem more fanciful, because planetary distance was important to D in the context of astrology. As you know, astronomy and astrology had been closely associated since antiquity, and that was certainly still the case in D's work. It was because of, not in spite of, his astronomical expertise that he was called on to suggest the most favorable date for Elizabeth's coronation, and later on to reassure the government that the new star was not a sign of impending catastrophe. Oddly, that Cate Blanchett movie depicts D delivering precisely the opposite message to Elizabeth, which might sound like a pedantic complaint, but it's worth knowing that D invoked science to argue for an optimistic, expansionist, and militaristic British foreign policy, lining him with the more hawkish members of Elizabeth's circle. But let's get back to astrology and the reason D was interested in planetary distance. Like other astrologers, he believed that the stars have an influence on earthly bodies and events. Unlike other astrologers, he believed that precise calculations needed to be made concerning the distance of the stars from the surface of the Earth. This would introduce a considerable complicating factor, since typically a document like a horoscope would only register the observed position of the stars in the sky, not worrying about how far away they are. D had a theoretical reason for insisting on this, namely that he believed astral influence to be conveyed along rays that connect the stars to that which lies below them. The influence is stronger when the star spends a longer time above the affected place, strikes the place along a line that is closer to the perpendicular, and crucially, is nearer to the Earth in terms of height. Here, D was actually drawing on a range of medieval texts, notably Robert Grossetest, Roger Bacon, and a Latin work called On Rays, which presents itself as the translation of a treatise by the Muslim philosopher Akindi. But D's writings on astrology are paradigmatic of Renaissance science. We can see this from one of his most important treatises, even though it is certainly not one that is easy to understand, the Monas Hieroglyphica, published in 1564. It takes its name from a symbol, the monas, which combines several shapes that represent astrological signs and the four elements. In so doing, it captures in a single image, or as D puts it, teaches without words, the central claim of the work, which is that the celestial world above is powerfully connected to the elemental world below. You might remember that Tycho Brahe called alchemy terrestrial astronomy, and D made exactly the same point, saying that celestial astronomy is like a parent and teacher to inferior astronomy, meaning alchemy. There are resonances with parasalsis too, as in the following typical example of the numerology found in the monas. Speaking of the letter X, D observes that it is the 21st letter of the Latin alphabet, and graphically consists of four intersecting lines which represent the four elements. His further analysis invokes the three alchemical principles from parasalsis and the seven metals recognized in alchemy. You probably won't be surprised to hear that D also speaks of his enterprise as a kind of kabbalah, albeit that he distances himself from both Jewish kabbalah, which he saw as a mere exploration of the Hebrew language, and the Christian appropriation of that tradition as we've seen it in figures like Pico della Miranda. As we also might expect from D, the astrological and alchemical science is more purely mathematical. What he's really after is something like a mathematical language for describing the web of causal relations between the higher and lower realms. Also typical are his grand claims for the possibilities open to someone who masters that language. Just as one can use knowledge of optics to manipulate light with mirrors, so the scientist can manipulate elemental bodies by understanding and manipulating astral rays, so as to imprint the rays of any star much more strongly upon any matter subjected to it than nature itself does. As I say, this is all to some extent familiar from other Renaissance scientists, mathematicians, and Platonists we've discussed before, like Pico, Ficino, Agrippa, and Paracelsus, all of whom were, as we've seen, available to D right there on the shelves of his library. But what comes next is going to sound more extravagant. As we can see from his book catalog, D had a long-standing interest in angels. For example, he consulted the works of the Pseudo-Dionysius, which included a treatise called The Celestial Hierarchy, an application of Neoplatonic metaphysics to the angelic realm, and he already speaks of contacting the angels during the time when he was writing his chief mathematical treatises. Nonetheless, we have to recognize a shift in his career, and indeed life, in the early 1580s, when he began to engage in serious consultation with so-called scryers. These were not scientists, but individuals who were, supposedly, gifted by nature with the ability to contact the angels. After initial dealings with a man named Barnabas Sol, D started to perform so-called actions with Edward Kelly. Kelly would quite literally look into a crystal ball and describe what he saw and what was said to him by the figures who appeared, while D took notes. It was in part under Kelly's influence that D abandoned England in 1584, going to central Europe to join the Polish aristocrat, Albert Laski, then on to Prague in an effort to win the support of Emperor Rudolf II. D's family suffered greatly as a result, from the lengthy travel and precarious economic situation, but the worst was still to come. We know from D's diaries that his wife Jane was often furious at the hold Kelly had over D, so one can only imagine how she felt when the following happened. Kelly told D that the angels wanted the two men to sleep with each other's wives, which they apparently went on to do. From our point of view, it's almost irresistible to see Kelly as a con man who exploited D's credulity in his desperate search to find something just as elusive as the Northwest Passage a shortcut to divine truth. But we should perhaps try to resist at least a little bit. Kelly himself sometimes warned D that they could be communicating with demons pretending to be angels, and on one occasion actually produced a book by Agrippa to point out that the so-called angels were plagiarizing from his works. This might have been just a canny strategy on Kelly's part to provoke D into reassuring him about the authenticity of the angelic revelations, or it may be that Kelly himself believed, or half-believed, that they were contacting some kind of supernatural force, and was himself uncertain about the nature of this contact. Thanks to our recent episode on Shakespeare's Macbeth and witchcraft, we are in a good position to appreciate such worries. As we learned, the 16th century was a time when belief in the possibility of communicating with spiritual beings was widespread, indeed nearly universal. Even skeptics tended to argue merely that while witchcraft is real, it is nearly impossible to prove. In this cultural context, it was not at all strange that one worry confronting D, and perhaps Kelly, was that they were unwittingly conversing with demons instead of angels. Effectively, D was worrying that he really was guilty of witchcraft, but he convinced himself otherwise, just as he convinced himself that Kelly was a genuine scryer. Both men, and apparently Jane D too, when complaining about her husband's activities, used the word kosiner, meaning a fraudster. Certainly, it was a pressing concern that the human scryer might be a kosiner. This was D's eventual verdict on his first informant, Barnabas Saul. But even worse was the possibility that the supernatural beings themselves could be kosiners. D's angelic conversations have, as you might imagine, raised questions about his place in the history of science. One reaction might be simply to lament the way that this sophisticated mathematician turned his back on serious research and succumbed to superstition. One of the leading scholars of D's thought, Nicholas Cluly, takes more or less this line. He says that Kelly drew D away from more sober scientific work, and comments, The greatest irony of D's career is that his attempts to get progressively closer to the truths of nature in fact led to a progressive distancing from nature. But as other scholars have noted, this may underestimate the extent to which interest in angels and magical practices were already on display in D's earlier career. It's not as if he was a hard-headed mathematician before he met Kelly and a wild-eyed magician afterward. Cluly himself stresses that D's intellectual ambition was always the same. He wanted to probe the depths of divine wisdom. It's just that he made a catastrophic mistake about which methods were best suited for reaching that goal. But I think that the consistency across D's career is deeper than that. It's not only that he had the same broad objective throughout, it's also that he operated with a stable theory of knowledge. This is a theory he could have found in other broadly Platonist authors of the Renaissance, like Agrippa. D shared his understanding of natural philosophy as a serious, but also a relatively low-ranking science, which studies the earthly realm of the four elements. Natural magic too has its place here. Higher up is the combined art of astronomy and astrology, and higher still is direct concourse with the divine realm. Similar methods could be used at the different levels, which is why it would have made sense to D when Kelly's angels outlined a complex language of symbols, not unlike the one explored in D's own Monos Hieroglyphica. This was supposedly a direct revelation of the original language of Adam, the first man. Through Kelly then, D could behold truths that were merely glimpsed from the perspective of the lower sciences. He said as much himself, writing to the emperor Rudolph II, I found that neither any man living nor any book I could yet meet with all was able to teach me those truths I desired and longed for. Which is why he instead chose to make intercession and prayer to the giver of wisdom and all good things. Of course, we would draw a sharp distinction between a mathematical empirical natural philosophy on the one hand, and on the other hand, talking to angels in a crystal ball. But for D, these were just lower and higher steps on the same ladder, which means that he would consider it a step down as we turn to the more conventional achievements in natural philosophy made in Renaissance Britain by men like Thomas Lineker and Thomas Harriot, which we'll be talking about next time here on The History of Philosophy Without Any Gaps.