 Hi, I'm Peter Adamson and you're listening to the History of Philosophy podcast brought to you with the support of Kings College London and the Leverhulme Trust, online at www.historyofphilosophy.net. Today's episode, Pythagorean Theorems, Iamblichus. Before he became the last pagan ruler of the Roman Empire, Julian the Apostate was a philosophy student, so don't ever let anyone tell you that studying philosophy isn't a good career move. One of Julian's teachers particularly impressed him with the following anecdote. It seems that a philosopher named Maximus invited this teacher to attend a ritual at the temple of the goddess Hecate. Incense was burned, a hymn was chanted. As Maximus performed these rites, the statue of the goddess that presided over the temple seemed to come to life. It smiled, and then laughed. At Maximus's command, torches held in the statue's hands burst spontaneously into flame. Julian's teacher regarded all this as mere trickery, but Julian himself reacted differently. He left town to travel to the city of Ephesus, where he might sit at the feet of this wonder-working philosopher. About a decade later, Julian would take the purple, and for a brief time, the religious and philosophical ideas of pagans like Maximus would become the basis for imperial policy. It was a last chance for Christians to be persecuted, and for the old gods to be venerated as divine patrons of Rome. However much he may have impressed Julian, Maximus was a mere footnote in the history of pagan Neoplatonism. His ideas, to the extent that we know about them, closely followed those of a far more influential thinker who was also much admired by Julian, Iamblichus. By the time of his death in 325, a few years before the birth of Julian, Iamblichus had set the tone for all subsequent pagan Platonists. It was the spirit of Iamblichus, more than Plotinus, that presided in both Athens and in Alexandria, the two main centers of Platonist philosophy in late antiquity. His philosophy was resolutely pagan. He introduced complex, even baroque, modifications to the simpler system of Plotinus, in order to make room for the many divinities recognized in pagan worship. He argued for the efficacy, indeed the absolute necessity, of the practice of theurgy, ritual activities that allow the gods and goddesses to reveal themselves in our world, as Hecate did at the behest of Maximus. Soon, the light of pagan philosophy would be extinguished by the new wind of Christianity that was blowing with ever greater force across the Mediterranean, but for a couple of centuries it sputtered on, fed mostly by the fuel of Iamblichus's particularly pious brand of pagan Platonism. Iamblichus hailed from Syria and the city now called Qinn-e-Srin. He was well-born and could supposedly trace his family back to royal forebears. Syria would have been a place of upheaval during his childhood. When he was born it was Roman territory, but the Persians invaded and rampaged through the area in the year 256. Any trauma he may have experienced has left no traces in his writings, though it is often said that Neoplatonic philosophy offered an escape from the uncertain world of late antiquity and it doesn't get much more uncertain than having Persians suddenly invade your country. Iamblichus eventually set up a school in Apamea, also in Syria, so that he is strongly associated with this eastern province of the empire. However, he may have traveled abroad to study with his fellow Syrian, Porphyry. Just as Socrates had taught Plato and Plato-Aristotle, so Plotinus taught Porphyry and Porphyry Iamblichus. And just like Aristotle, Iamblichus reacted critically to the writings of his teacher and of his teacher's teacher. As we have seen, the idea that Plotinus founded a new tradition called Neoplatonism is itself built on rather shaky foundations. He reacted, often critically, to previous Platonists without seeing himself as initiating a new philosophical movement. In fact, Iamblichus changed Platonism just as much as Plotinus had done. Perhaps most important was his advice about how to study Platonic philosophy. Iamblichus laid down an order of reading for Plato's works, which included twelve dialogues, beginning with those he took to focus on ethics, the Alcibiades as a kind of introduction to Plato and then the Gorgias and Phaedo. The student should then graduate to theoretical philosophy, covering philosophy of language with the Cratylus, theory of knowledge with the Theaetetus, and so on. The last dialogues to be studied were the Timaeus and the Parmenides, which, for Iamblichus, contained the whole of Plato's thought, the Timaeus teaching us about nature and the Parmenides about theology. But all the dialogues could be mined for insights about the gods. The Middle Platonists, Plotinus and Porphyry, were certainly pagan believers, who referred to their metaphysical principles not only as intellect or the One, but also as gods. And they would have agreed with Iamblichus that the dialogues taught their readers about theology. But with Iamblichus, we have something new. No longer is pagan religion simplified and rationalized as a philosophical system. Rather, there is a perfect fit between the systematic and the sacred. Iamblichus multiplies transcendent entities by invoking complex rules of causation. What was a single level in Plotinus, like intellect, will be divided and then subdivided into many intellective gods that play different metaphysical roles. This results especially from Iamblichus' principle that between two causes that have different natures, we must postulate another cause that shares features of both. For instance, he assumes that if we have immaterial gods who transcend the cosmos, and also the physical cosmos itself, there must be a kind of entity which shares aspects of both. These will be the stars, or heavenly gods, which share in both the divine nature of the immaterial gods and the physical nature of bodies. For Iamblichus, this provides a philosophical rationale for ascribing divinity to the heavens, a welcome result given that pagan religion involved worshipping the planets and stars. Iamblichus refers to these additional mediating entities as means, the way that 3 is the mean term between 1 and 5. The use of mathematical language is no accident. Taking a leaf from the middle Platonists, Iamblichus sees Plato as a venerable branch growing from even more ancient roots. Like Plutarch and others, he assumes that a primordial wisdom has been passed down not only in Greek culture, but also in Egypt and further east. Within Hellenic literature, he sees Pythagoras as the foremost figure and as a forerunner of Plato's teachings. Thus, Iamblichus would describe himself as a Pythagorean as much as a Platonist. Listeners with exceptionally good memories may recall that I mentioned Iamblichus all the way back in episode 4 as a source for legends about Pythagoras speaking to bears, having a thigh made of gold, and so on. In that episode, I also promised to get to Iamblichus one day. Sorry for the long wait. Iamblichus so esteemed Pythagoras that he wrote an enormous series of Pythagorean books, including the Surviving Life of Pythagoras, which I was using in that episode, and Treatises on the Philosophical Significance of Mathematics. Being a Pythagorean, Iamblichus believed that mathematics, no less than the Platonic dialogues, could be mined for insight about transcendent divinities. But in keeping with his idea of an ancient wisdom received by many cultures, he looked beyond Plato and Pythagoras. As we saw when looking at Plutarch, Hellenic pagans were happy to absorb Egyptian gods into their pantheon, and even to identify certain Egyptian gods with certain Greco-Roman divinities. So, naturally, Iamblichus identified Egypt as a source of great insight. This particular tributary of the stream of antique knowledge flowed above all through the body of works ascribed to thrice-great Hermes, a divinity who was both the Greek god Hermes and the Egyptian god Thoth. They record Hermes's own education from a character named Poimandres, and the lessons he gives to his own disciples, including the god Asclepius. The text reads more like a sacred or mystical work than a philosophical treatise, but it resonates strongly with Platonist philosophical doctrine. For instance, the opening passage of the first book tells of an intellective first god who gives rise to a logos, a word or reason. We've already seen this idea in Platonists like Philo of Alexandria. That's no coincidence since the text emerged contemporaneously with Middle Platonism. What Iamblichus saw as an inspired and ancient source of Platonic truths was in fact itself derived from the Platonist tradition. The same goes for an equally important source used by Iamblichus, the Chaldean oracles, named for their supposed origin in the eastern land of Chaldea. Produced in the 2nd or 3rd century AD, the oracles present a visionary description of the universe and its causes. In this system, the transcendent causes of Platonist metaphysics are personified as divine characters. A first mind and a secondary intellect are referred to as father gods, with the soul being associated with Hecate, the same goddess who obligingly smiled and laughed for the philosopher Maximus. Of course, Iamblichus could have found this kind of metaphysical system, with or without the mythical trappings in any number of Platonist texts. The reason he constantly alludes to the oracles and the works of Hermes is that their supposed pedigree proved the venerable and sacred roots of Pythagorean and Platonic teaching. Later Neoplatonists will invoke the antiquity of pagan belief and its supposed appearance in Egyptian and Eastern cultures as a proof of its superiority over the far younger faith of the Christians. Furthermore, these texts provided the pagans with scriptures that could compete with the Bible. But Iamblichus, unlike his master Porphyry, was not unduly concerned by the Christians. He worried more about newfangled innovations among his fellow pagans. They should turn to texts like the oracles to learn the authentic ritual practices. Even when Iamblichus gave his attention to more mundane philosophical topics, he kept his eyes turned towards the gods. As a student of Porphyry, he knew better than to neglect his Aristotle, and like Porphyry, he was particularly interested in the logical works. He wrote a commentary on Aristotle's categories, now lost but known indirectly through later commentators. His ideas here make an interesting contrast to both Porphyry and Plotinus. For Porphyry, the categories was relevant only to physical things, and analyzed certain terms in our language insofar as they applied to such things—a useful, albeit limited, ambition. Plotinus, by contrast, had extensively attacked the categories, trying to expose them as an inadequate attempt to classify reality. Plotinus preferred the set of concepts called the greatest kinds in Plato's dialogue the Sophist, which we discussed a while back in an interview with Fiona Lee. These five kinds—being, rest, motion, sameness, and difference—are the true anatomy of reality, used by Plotinus to describe the intelligible world of intellect. In a characteristically bold move, Iamblichus instead gave a so-called intellectual interpretation of Aristotle's categories. Rejecting Porphyry's peacemaking suggestion that the categories were limited to the humble things of the physical cosmos, Iamblichus insisted that all ten categories could be applied also to the intelligible divine world. I'll mention just one example of how this worked. In discussing the category of substance, Aristotle said that substances alone can change in their properties. For instance, a giraffe can go from being hungry to being not hungry, whereas non-substantial properties like the giraffe's hunger are incapable of this. Iamblichus has no quarrel with Aristotle's claim, but as always he wants us to raise our minds to a higher level. Intelligible substance, he says, is like this too. The difference is that it can have two contrary properties at the same time. Ironically, he gives the very example Plotinus had used. Intellect partakes of the greatest kinds of the sophist, so that it is both moving and at rest, both the same as and different from itself. And likewise for all the categories, each of which applies to physical things in one way and to the intelligible in another, more exalted way. Iamblichus' critical attitude towards Plotinus is even more obvious when he turns to one of Plotinus' most distinctive doctrines, the undescended soul. As you'll remember, Plotinus believed that every soul remains connected to the intelligible realm at all times. Even now, as you listen to this podcast, some part of you is communing with the forms. It's a cheerful proposal, but Iamblichus is having none of it, and subsequent Platonists unanimously side with him against Plotinus. He raises obvious objections, for instance that if we are already connected to intellect all the time, and if intellectual contemplation is the ultimate fulfillment and happiness for mankind, then we are all always fulfilled and happy, whether we know it or not. This is not only rather weird, but means that there is no reason for us to try to improve ourselves through philosophy. After all, we're already perfectly happy. Iamblichus makes other objections that are more distinctively, well, Iamblichian. Because he has populated his metaphysical hierarchy with many more kinds of entity than Plotinus, he does not believe that the human soul is continuous with pure intellect. There are not only lower divinities, like the heavenly gods we've already mentioned, but also lesser supernatural beings like demons and heroes, better than humans but worse than gods. Again, Iamblichus postulates these beings to ensure that philosophical doctrine and pagan religious belief match perfectly, but he also has a more principled reason. Heroes and demons are possible kinds of beings, and if they didn't exist, then their absence would leave a kind of gap in the metaphysical scheme. Iamblichus's mean terms provide continuity between different levels of the scheme, a point that also applies to the soul itself. It is quintessentially a mean between the bodily and the immaterial. Whereas Plotinus often seems to make the soul nothing but a subject of attention, turned either up towards intellect or down towards body, Iamblichus emphatically gives soul its own distinctive nature. His verdict is that Plotinus's optimism led him to violate this nature by putting the soul beyond its proper station. This of course leaves us with a problem. If we are not always already in touch with intellect, how can we make contact? The problem is especially pressing for Iamblichus since he is so insistent that the intelligible things are not just forms, but gods. If we cannot access the intelligible, there will be not just philosophical frustration, but dire religious consequences. Iamblichus's answer is that we reach the gods through the ritual practices described in the Chaldean oracles and admired by Julian, the practices of theurgy. Literally theurgy means god-making. It applies to a wide range of exercises and undertakings including the animation of statues described at the beginning of this episode. Divination of various kinds was also theurgic, as were such religious customs as the chanting of hymns and apparently meaningless words of power, the sacrifice of animals, the use of artifacts like sacred stones, and so on. Iamblichus was forced to defend the efficacy and integrity of theurgy, and hence of religion as he understood it, against questions posed by his own master, Porphyry. We saw last time how Porphyry was led by his inquisitive and somewhat skeptical instincts to reject animal sacrifice. He also wrote a more general work questioning the tenets of theurgy. Adopting a tone rather like that of Plato, criticizing the Homeric myths, Porphyry complained that many theurgic practices seem inappropriate to the gods. In some rituals, for instance, one would utter obscenities or display effigies of the male genital organs. At other times, the theurgist might aim commands or threats at the gods. Above all, Porphyry could not see how the physical actions of theurgy could affect the transcendent and immaterial gods. In reply, Iamblichus composed a work usually called On Mysteries, the title given to the treatise by the Renaissance philosopher Marsilio Ficino, who also translated it into Latin. I hereby promise to get to Ficino someday, too. It will be another long wait. In On Mysteries, Iamblichus responds to Porphyry that we are not forcing the gods to do anything with our theurgic practices. Rather, the gods are present everywhere at all times in the cosmos. The ritual just allows their presence and influence to become manifest. The apparently obscene and repellent practices noted by Porphyry are merely symbolic and, when interpreted rightly, need offend nobody. The ritual sacrifice is indeed inappropriate to the highest, purely immaterial gods, but it is effective for communing with the gods within the cosmos, those heavenly divinities again. In addition to fending off these objections, Iamblichus makes a spirited case, pun intended, on behalf of the religious practices. It is theurgy and theurgy alone that allows us to communicate with the intelligible gods. When Porphyry objects that the theurgist seems to be trying to pull the gods down to his own physical level, Iamblichus replies, no, the theurgist is trying to purify his own soul, and the souls of others, so that they may rise up to the gods. This is a shocking claim. Platonists, beginning with Plato himself, had always been trying to achieve likeness to God, to borrow the famous phrase used in Plato's Theaetetus. But from Aristotle down to Plotinus, it had always been understood that the path to this goal was philosophy. Iamblichus is the first Platonist to seriously question this rather smug philosophical claim. At one point, he sarcastically remarks that Porphyry is slipping away into philosophy, which makes philosophy sound distinctly second-rate in comparison to the sacred activities of the theurgist. This aspect of On Mysteries has alarmed some readers. The great scholar E.R. Dodds called the work a manifesto of irrationalism, and even some historians of philosophy who have great respect for Plotinus get impatient with the religious and ritualistic proclivities of Iamblichus and subsequent pagan neoflatanists. But we should note that Iamblichus's argument for the necessity of theurgy is itself philosophical. He bases himself ultimately on an idea familiar even from Aristotle, that every possible kind of being must be expressed in reality. It is anything but irrational for Iamblichus to follow this to its logical conclusion by positing mean terms between different kinds of entities so that the entire fullness of being will be realized. One consequence is that human souls must occupy a much lower rank than the exalted gods of the intellectual realm and have a distinctive activity that falls far short of divine intellectual activity, whatever Plotinus might think. Iamblichus seems to make an exception for certain so-called pure souls. They occupy yet another mean between normal human souls and the gods. These pure souls belong to men like Pythagoras and Plato who have been granted a direct insight into the gods. But for the rest of us, theurgy is indispensable. It is the only way for a soul to transcend its own limitations by availing itself of divine assistance. Thus, the real goals of theurgy are purification and assent, not making the statues smile or divining the future. If Iamblichus did use theurgy to predict future events, he may have discovered the good news that he had managed to set the agenda for the last generations of pagan philosophers in antiquity. The bad news was that these would indeed be the last generations. Christianity was on the rise, and pagan thinkers would be increasingly embattled. The next great Plotinus thinker we'll consider refers in one work to the destruction of his home, and it has been speculated that it may have been wrecked by Christians in anti-pagan violence. We can't be sure about this, which shows that nowadays we can't even tell the past, never mind telling the future. Nonetheless, I'll risk predicting that you'll want to join me as I look at Proclus, next time on the History of Philosophy, without any gaps.