 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 historyoffilosophy.net. Today's episode, The Men Who Saw Tomorrow, Renaissance Magic and Astrology. When I was about 10 years old, I saw a documentary on television called The Man Who Saw Tomorrow, about the 16th century astrologer and soothsayer Michel de Notre Dame, also known as Nostradamus. It credited him with accurately predicting many historical events, from the French Revolution to the Kennedy assassination, and went on to suggest that he had also predicted a nuclear apocalypse in the decade to come. I was absolutely terrified, still today I can remember being unable to sleep, convinced that World War 3 had already been foreseen in the Renaissance. So I can imagine pretty well how people back in the Renaissance felt in the 1420s, when a number of astrologers warned of a great flood owing to a conjunction of Mars, Saturn, and Jupiter in the sign of Pisces. After the resulting panic proved to be unfounded, Martin Luther pointed out that, whereas the flood hadn't happened, there was a huge peasant uprising instead, of this no astrologer had breathed so much as a word. Nowadays, most people over the age of 10 chuckle at the idea that astrological predictions could be accurate, even if most of us also know our star signs and peek at the horoscopes in the newspaper now and again. But in the 15th and 16th centuries, as in antiquity and the Middle Ages, there was widespread, sincere belief in the efficacy of astrology and the closely related practice of magic. This conviction could be found at the highest echelons of society. You might recall that Christine de Pizan's father was a professor of astrology and went with his family to the court of Charles V, whom Christine called Roi-Hassologien. Predictions based on this science could enhance political legitimacy or have the reverse effect, which is why it was possible to get in serious trouble for predicting the death of rulers and popes. In a study of the use of astrology in Milan, the scholar Monica Azzolini has shown how members of the powerful Sforza family retained astrologers to advise them. When the sickly Giangagliazzo Sforza died prematurely in 1494, his doctors explained their failure to keep him alive in astrological terms. His modest lifespan was foretold in his nativity. Still, they did their best to ward off this fate, constantly consulting the stars, at one point delaying treatment until a conjunction of the moon with Mars had passed. But this noble patient's death was inevitable due to the terrible influence of the heavens. Besides which, Giangagliazzo refused to stop eating dangerous fruits like pears, plums, and apples. Had he also partaken of melon, the doctors would probably have considered it a suicide. We can see from this example that astrology was closely connected to medicine. To cast the horoscope of one's patient was like taking a medical history, and observation of the stars could influence both diagnosis and prognosis. This is illustrated well by the controversial notion of critical days, which goes all the way back to Hippocrates and Galen. Both ancient doctors asserted that there are pivotal junctures in the development of an illness, which fall on days 7, 14, and 20, when the patient will either take a turn for the worse, or begin to recover. Galen proposed that critical days are determined by the cycle of the moon, which is divided into periods of somewhat less than 7 days, which is why the third critical day is the 20th, and not the 21st. Unfortunately, his explanation of the astronomy governing this was not very convincing, in part because he failed to take account of variation in lunar cycles. So attempts were made to fix up the theory. Pietro d'Abbano, an enthusiast for medical astrology, suggested a more elaborate theory that matched the four humors to different plants, and he also tried to improve the mathematical rationale underlying the sequence of critical days. Girolamo Cardano was unimpressed by the Galenic account and said that when it comes to the study of the stars, one should listen not to Galen, but to Ptolemy and Hippocrates. This is what we might expect Cardano to say given his enthusiasm for both these ancient authors. He was deeply committed to the authoritative status of Ptolemy, who had written fundamental works in both astronomy and astrology. Cardano was deeply committed to astrology too. Curiously, he did not draw that much on astrology in his medical works or often discuss medicine in his astrological writings. Yet he was confident that astrologers like himself could predict important events, or at least explain in retrospect why they had happened, as with the outbreak of syphilis in Italy or the rise and fall of world religions. He foresaw a renovation of all religions, owing to an astral conjunction, and looking back into history, explained such events as the rise of Islam and the fall of Byzantium with reference to the stars. The events of an individual person's life could be explained in the same way. Cardano tells of an amazing feat he himself performed, when he correctly divined that a certain person he had never met must have eye troubles and a scar made by an iron weapon, all based solely on a nativity. A nativity, I should explain, is a horoscope based on the position of the planets, including the sun and moon, at the moment of a person's birth. Cardano was not the first to produce and analyze nativities, but he was the first to author a printed collection of them. He believed that such horoscopes foretold the eloquence of Petrarch, the learning of Trapezuntius, the theological acuity of Savonarola, and the brilliance and early death of Pico della Mirandola. Regarding Vesalius, whom he much admired, he wrote that Mercury in trine with Jupiter and Venus in quadrature indicate wonderful genius and eloquence as related to his art. Cardano courted controversy by also publishing the Nativity of Jesus Christ. This appalled Cardano's many critics. One of them said it was impious audacity to suggest that the stars might rule over the Savior himself. But Cardano denied that devotion to astrology equates to a belief in astral determinism. Rather, it tells us about the conditions that will prevail, which is useful precisely so that we may be prepared for them. He gives the example of knowing that there will be a heat wave and bringing a flock of sheep to a cool place so they will not die. As with medicine and other areas of the humanist movement, the Renaissance approach to astrology often involved an attempt to purify the discipline from medieval accretions, especially those from the Islamic world. Cardano wanted to make astrological practice authentically Ptolemaic and free it from the influence of Abu Ma'shar, al-Khabisi, and other scientists of the Islamic world, whom he called a crowd of idiots. Agostino Nifo took a similar view. For him, Abu Ma'shar was a prince among the fabulous who had distorted Ptolemy's original teachings. These Ptolemy purists rejected such practices as using astrology to make specific decisions, for instance when to marry, or whether to make a journey. This technique of interrogations, which played a significant role in Arabic astrology, was not even mentioned by Ptolemy. And for good reason, said Cardano, since they are magical and unworthy not only of a Christian but also of a good man. Another disputed point was planetary conjunctions, such as the one invoked in that prediction about the flood. Abu Ma'shar spoke extensively about their effects and invoked them to explain religious and political upheaval. As already mentioned, Cardano followed suit, but the idea was criticized by other authors. Among these, none was more critical than Pico della Mirandola. Our recent interview guest, Darben Nicholas Hasse, has written that conjunction theory was a main target of Pico's Disputations Against Judicial Astrology, published posthumously because he was still at work on it when he died. Pico is relentless in his attacks on astrologers of the Islamic world, who made mistakes and also misread Ptolemy. Charging the 11th century astrologer Ibn Uredwan with one such misinterpretation, he demands, what do you hallucinate, barbarian? Pico's formidable intelligence and historical knowledge is brought to bear to cast doubt on astrology as a science. It was not, he points out, even discussed by such ancient authorities as Pythagoras, Plato, Aristotle, Seneca, Cicero, and the Church Fathers. Apparent counterexamples, like a work ascribed to Aristotle called Secret of Secrets, are, correctly, argued by Pico to be inauthentic. If astrologers get things right occasionally, this is simply a matter of chance, because the stars simply have no influence on particular people or events. Which is not to say that they are entirely without influence, that would be an untenable claim given the obvious effect of the sun on climate and of the moon on the tides. But their effect is, says Pico, general, and affects all equally, promoting the natural cycle of life and not, for instance, the progress of a disease in an individual patient. Pico seems to have had several reasons for writing this polemic. The diatribe against the so-called Arabs and their distortion of ancient science is, of course, a well-worn humanist trope. At a philosophical level, the thing that bothers him above all would seem to be the deterministic implications of astrology. As we just saw with the example of Cardano, some embraced the art of astral prediction without supposing that the stars determine everything. Pico, though, was convinced that astrology is incompatible with the Christian commitment to free will. In this he found an ally in Savonarola, another man who railed against astrology. Their attitude was shared by the historian and political thinker Guicardini. Along the same lines as Pico, he noted that astrologers may seem to be more successful than they really are because people only remember it when predictions come out true. Of course, when astrologers did get it wrong, their opponents were ready to pounce, as when the medical writer Giovanni Mainardi told the story of a doctor managing to heal someone whose death had been foretold by a stargazer. In some cases, the infective could get personal. One critic cruelly asked, if Cardano was such a brilliant astrologer then, why didn't you keep the axe from your son's neck? Yet Pico's disputations also provoked numerous defenses of astrology, for example, by Lucio Bellanti and Giovanni Pontano. Often, such defenses used the same tactic we found in Nifo and Cardano of blaming all problematic aspects of astrology on the Arabic tradition, so as to preserve the authoritative status of the Greeks. Moderate views were also proposed, as by the Platonist cosmologist Francesco Patrizzi. Like Cardano, he rejected determinism, but retained such astrological ideas as the malicious nature of Mars and Saturn, and favorable nature of Jupiter and Venus. In common with other learned defenders of astrology in the 16th century, he warned his readers not to confuse superstitious and irreligious practices with the properly scientific discipline that explores the causal influences of the stars on our world, especially the influences more subtle than what we can see in the obvious cases of the Sun and the Moon. Ironically, another occult science, magic, was defended in very similar terms by none other than Pico della Mirandola. In the list of conclusions he intended to defend at Rome, he distinguished between natural magic and magic that invokes powers of darkness. The latter is rightly condemned by the Church, while the former is permitted, and can be based upon universal theoretical foundations. Indeed, magic is the noblest part of natural science. For Pico, the correct approach lies in the study of the Jewish mystical tradition he calls Kabbalah, so that magical powers may be discovered in Hebrew words or Kabbalistic numerology. He also approves of the ancient Greek Orphic hymns as an important body of magical teachings and draws a parallel between them and the Hebrew tradition, just as the hymns of David miraculously serve a work of the Kabbalah, so the hymns of Orpheus serve a work of the true, permitted, and natural magic. In his list of propositions, Pico also draws connections between magic and astrology. This suggests that he may have at first looked favorably on astrological science but changed his mind later, leading him to write his Disputations in order to debunk the pretensions of the astrologers. But the great Renaissance proponent of the links between magic and astrology was Pico's older friend, Marsilio Ficino. One of Ficino's most remarkable and controversial works, The Three Books on Life, has been called by another of our interview guests, Denny Obichaux, a handbook for helping scholars and philosophers stay healthy, live long lives, and bask in the heavens' glow. The first of the three books offers largely conventional medical advice, based on the principle that aging is caused by gradual loss of the body's moisture and the vital heat that nourishes that moisture. But as the work goes on, Ficino delves increasingly into astrology and magic. In Book 2, he describes two extreme ways of life, one associated with Saturn and characterized by relentless pursuit of contemplative knowledge, the other associated with Venus and involving the pleasures of the flesh. Both have a pernicious effect on health, but the Saturnian lifestyle is preferable, because as Ficino wittily remarks, the wisdom attained through Saturn secures one an eternal life, whereas the sexual delights of Venus give life to someone else. Ficino saw himself as having a Saturnian personality, something he explained by the fact that Saturn was entering Aquarius when Ficino was born in October of 1433. Thus, he is intellectually gifted, but also moody, given to melancholy. He can at least comfort himself with the thought that all the great men who have ever excelled in art have been melancholic. Like Cardano, Ficino holds that knowledge of astrology helps us to shape our futures rather than telling us of an inescapable fate, so our actions can prolong our lifespan, and Ficino tells us how, explaining that one may use knowledge of one's astral nature to choose beneficial diet and medical treatment. He mentions with approval the theory of critical days and the progress of a feverish illness, and explains that the vital spirit that courses through the body responds especially to the power of mercury, since spirit is mostly air, and mercury is associated with this element. Straightforwardly magical practices like the wearing of talismans are also discussed. Here, Ficino is somewhat skeptical. While such instruments may do some good, this is probably more because of the innate powers of the stones and metal than the shapes into which they have been carved. Standard medical treatment is more reliable than something like a magic ring. The modern reader is apt to think that Ficino's moderate skepticism is not nearly skeptical enough, but he offers a well-considered theory to explain magical phenomena. To see why it is plausible, consider magnetism. All the way back in the time of the pre-Socratics, philosophers had already been interested in this phenomenon. Thales of Miletus said that the magnet must have a soul in it, presumably because it can move of its own accord toward metal. But of course, neither the Greeks nor the medieval had any understanding of magnetic force. For them, it was an occult power, in the sense that its working is hidden. The same can be said of other puzzling natural phenomena, like the power of stingrays to stun their victims. Belief in magic can be seen as an extrapolation from these cases. An object like a talismanic stone may have an occult power of its own, which it acquired while forming in the earth, thanks to the influence of the stars. If magic is simply the manipulation of such natural powers, then there is nothing wrong with it, any more than it would be wrong to use a magnet. As Cardano would later say, magic is nothing unless you place it as part of either medicine or natural philosophy, and understood in this way, magic is no more illicit than carpentry. Furthermore, Ficino has a way to explain how the hidden or occult forces work, namely that the whole universe is held together by bonds of sympathy. He tells us that the third book of his treatise On Life developed out of his commentary on Plotinus, which explains his use of the sympathy theory. Plotinus too invoked this originally stoic concept to explain a range of natural phenomena, including even human vision. For both Plotinus and Ficino, the idea has a pleasing affinity with Pythagoreanism too. Ficino illustrates it with the case of two string instruments which vibrate in sympathy with one another. Very appropriately, considering that this podcast episode is being released on Valentine's Day, Ficino also integrates his account of magic with his theory of love, which we discussed in an earlier episode. The whole cosmos does have a unifying love or sympathy, but there is a particular bond between things that have relevant similarity. Love is itself a magician, says Ficino, because an act of magic is the attraction of one thing by another in accordance with a certain natural kinship. This is why, according to Ficino, people of the same star sign are apt to fall in love with one another. It's also why planets are linked to certain bodily constitutions, material substances, colors, and so on, and why there can be a science for studying and exploiting such resonances. Again, these are entirely natural powers and effects, like the magnet. If love is a magician, then nature herself is a sorceress. But Ficino knew that he was treading on dangerous ground, and wrote an apology to explain why he had written so much about magic. He imagines critics complaining, Marsilio is a priest, isn't he? Indeed he is. What business then do priests have with medicine or, again, with astrology? Another will say, what does a Christian have to do with magic or images? In his own defense, he protests that he only ever practices natural magic, as opposed to seeking concourse with demons. Not that he doubts the existence of demons. They are regularly invoked in the Platonist literature Ficino knows so well, with the most famous example being the divine voice of warning heard by Socrates, as mentioned in the Platonic dialogues. A somewhat more recent source was our old friend Michael Psaros, whose work on demons was translated by Ficino. Following Psaros, Ficino distinguished demons into various types, classified in terms of their connection to different elements and planets. These resonances explain why astral magic can summon demons, or induce them to influence our world. But the fact that we can do this doesn't mean that we should. Even enthusiasts for magic often disavowed demonology, like Giammatisto della Porta, whose treatise Natural Magic appeared in several editions beginning in 1558. The title is carefully chosen. To engage in natural magic is precisely to avoid techniques that involve demons, and instead to follow the lead of noble investigators of occult forces, like Pythagoras and Plato. If such reassurances were designed to keep della Porta out of trouble with the authorities, they didn't work. His book was placed on the index of prescribed books by the papal inquisition, and unsurprisingly so, given that it discussed such things as the Witch's Solve, a potion that allows witches to teleport to black sabbaths. To be fair though, della Porta discussed the Witch's Solve in order to provide a naturalist account of something that only seemed like magic or witchcraft. The potion affects the imaginations of those who imbibe it, and makes them think they have been elsewhere. This detail fits with an emerging picture of Renaissance attitudes towards the occult sciences, namely that a sober, scholarly approach would explain some magical phenomena while rejecting others in a display of sound scientific skepticism. Hence, Pico embraced magic but turned against astrology. Ficino thought Taliesin's work, but probably only because of the metal they're made of, and even Cardano admitted that astrology was a merely probable art. This is why his own predictions were sometimes wrong, in one case happily so. He forecast regular illnesses for his daughter, but she enjoyed good health. Even the most skeptical thinkers had to allow some scope for the supernatural, as we can see from the case of Pietro Pompanazzi. His work On Incantations from 1556 is a splendid example of debunking, which shows how apparently magical effects can be explained without recourse to magic. You might remember that in the interview with Dag Hasse he told us about how Pompanazzi undermined the story of a miraculous appearance of Saint Celestine, which put an end to torrential rainfalls. Pompanazzi was also unimpressed by the use of demonology to heal illnesses. Do the demons carry with them boxes, satchels, and bags full of plaster, like surgeons and apothecaries? But even Pompanazzi had to admit that genuine miracles do sometimes occur. These are not brought about by human magicians but by God, and they are beyond the power of human reason to explain. From this we can see that these skeptically-minded philosophers had to tread just as carefully as the believers in magic and astrology. The happy and orthodox medium was to accept that some things are beyond our ken, while steering clear of demonology, astral determinism, or tracing the rise of religion or incarnation of Christ to the effect of the stars. The authoritative response was similarly ambiguous. Papal bands were placed on only some forms of magic, de la parta was put on trial but not convicted, and he managed to get his treatise on magic taken off the index through some judicious revision for a further edition. Much depended on who was pope at any given time. When Inquisitor-General Michela Ghislieri took the post in 1565, that heralded a time of repression, but half a century later Campanella found himself conducting a magical seance with Pope Urban VIII to ward off his death by astral influence, a story that embarrassed the pope once it got out. So you could get away with a lot at some points during the Renaissance, while at other points the popes were more dangerous even than melons. The key thing was to know which lines not to cross, a task at which the protagonist of our next episode failed miserably. Giordano Bruno, victim of Renaissance Italy's most notorious act of persecution. That's here next time on The History of Philosophy Without Any Gaps.