 Hi, I'm Peter Adamson, and you're listening to the History of Philosophy podcast, brought to you with the support of King's College London and the Leverhulme Trust, online at www.historyofphilosophy.net. Today's episode, The Joy of Sects, Ancient Medicine and Philosophy. The ancient Egyptian practice of mummification was a lengthy and complex one, which took many weeks. The first step in the process was naturally making extra sure the person to be mummified was dead. Then the process of embalming began, which meant removing the body's internal organs. The abdomen would be emptied through an incision while the brain was extracted through the nose. Afterwards, these organs would be wrapped in bandages and popped into jars to be placed in the tomb with the mummified body. Now, I know what you're thinking. Yuck. It's a fair point, and one with which the ancient Greeks would have agreed. In classical Greek civilization, there was a firm taboo against the dissection of human bodies. Thus, Aristotle, for instance, did not extend his program of anatomical investigations, past fish and other animals, to include humans. Of course, battlefield injuries and so on occasionally provided a glimpse into the secret recesses of human bodies, but Greek science included no systematic investigation of human anatomy. Until, that is, the third century B.C. At the beginning of this century, ancient science as a whole received one of its greatest boons. You may recall from the episode that introduced Hellenistic philosophy that after Alexander the Great, the Greek-speaking world was split into three powers, the Seleucids in the east, the Macedonians in Greece and the Balkans, and the Ptolemies in Egypt. In about 300 B.C., Ptolemy I chose Alexandria as the site for an ambitious project, a library, which would gather together all the writings that could be found on all topics, and a so-called museum. The name refers to the muses in whose honor and with whose guidance activities in the museum would be conducted. Scholars and scientists would receive free lodging in the museum, along with a place to do research to collaborate and investigate. Alexandria thus became a center for intellectual inquiry, and it remained so until late antiquity. It was here, perhaps in the museum itself, that the first anatomical dissections of human bodies were carried out. We have no texts reporting on these dissections at first hand, but from later authors we know that the two main anatomists were named Herophilus and Erisistratus. It's an interesting question why these two boldly cut where no one had cut before. Certainly the protection of the Ptolemies themselves was a factor, and it's often speculated that the long-standing practice of organ removal in Egyptian funeral practices may have provided a precedent. If you can have your loved one's brain pulled out through their nostrils for the sake of a religious burial, it is perhaps less unthinkable to dismantle strangers in the name of science. But Herophilus and Erisistratus were culturally Hellenic, not Egyptian, and they would certainly not have been involved in any such local religious practices. Indeed, there is some ancient evidence that they left out that crucial first step in the mummification process, the part where you make sure the person is dead. Later authors tell us, with breathless dismay, that these Alexandrian anatomists dissected criminals who had been condemned to death while they were still alive. Whether or not this is true, there's no doubt that the doctors of Alexandria took a great leap forward in the understanding of the human body and of medicine as a whole. Perhaps the most dramatic advance was the discovery of the nervous system, and the realization that this system is distinct from the system of blood vessels. This showed that there are two major networks spread throughout the human body, one branching from the brain and spinal cord, the other branching from the heart. And that raised questions of far-reaching, and indeed philosophical, importance. How did these systems relate to other phenomena, like breathing and the motion of the muscles? What did these discoveries mean for our conception of human nature itself? If we have an immaterial soul, could we now give a more detailed account relating soul to these physical structures? Or should the human body be understood as a bewilderingly complex machine? After all, it has parts that function like everyday instruments already used by the ancients. The lungs, as Erisistratus pointed out, could be compared to a blacksmith's bellows, while the liver and bladder seemed to function like filters or strainers. The discoveries at Alexandria thus posed a challenge to philosophers, who would need to accommodate the new anatomy within the philosophical school traditions they followed. But of course, a conversation between medicine and philosophy had already been going on for centuries. Plato already mentions Hippocrates, whose supposed writings were incidentally probably gathered for the first time at the Library of Alexandria. We saw in a much earlier episode that the Hippocratic works are themselves of great philosophical interest. Plato and Aristotle may not have gone in for human dissection, but both had things to say about human anatomy and other medical topics. The influence went the other way also. Aristotle, in particular, made a great impact on medical authors. For instance, Diocles of Caristus was a near-contemporary of Aristotle who emphasized the importance of the four humours, blood, phlegm, bile, and black bile. Following on suggestions in the Hippocratic corpus, Diocles understood health as a balance of these humours. While we don't find this elaborate humoral theory in Aristotle himself, he alludes to similar ideas. For example, when he describes people of a certain character as melancholic, the word comes from the Greek for black bile. Another figure influenced by Aristotle was Praxagoras, who provides a link to our Alexandrian investigators because he was the teacher of Herophilus. He made an influential, though incorrect, contribution to anatomy by defending a theory about the blood vessels and how they relate to respiration. For Praxagoras, the veins are full of blood, but the arteries are filled with breath, in Greek, pneuma. This is still the position we find in Aristotelis, and to some extent it goes back to Aristotle, who had emphasized pneuma as a kind of physical life force that pervades and sustains the body. Even in later authors, like Galen, who realized that the arteries contain blood, just like the veins, pneuma remains a vital substance, in every sense of the word vital. It becomes standard to assume that the nerves are allowing us to control our bodies through pneuma that passes along hollow channels within the nerves. Of course, to get to that theory, the Greeks first needed to discover nerves in the first place. Particularly important in this story is Herophilus, whose bad record regarding the humane treatment of criminals is balanced by his contributions in medical research. How he stands overall is perhaps a question we can set aside for a few years until we've reached John Stuart Mill and covered utilitarianism. It was he, Herophilus, not Mill, who distinguished between the sensory and motor nervous systems. His work survives in the very terminology of modern anatomy. For instance, he christened one part of our body the pineal gland because of its resemblance to a pinecone. Both he and his master Praxagoras also pioneered in medical diagnosis by laying great emphasis on the pulse. Much later in the Roman Empire, Galen still valued the pulse as one of the most important diagnostic indicators. Also important is the fact that Herophilus wrote on women's medicine in a treatise describing what makes someone a good midwife. Ancient medicine is one of the richest traditions for classical discussions of women, and, again, we see much later figures like Galen writing extensively on gynecology. Of course, anatomy and gynecology were only two strands in the ancient medical tradition. In the Hellenistic period, we also see authors contributing to pharmacology by transmitting lists of naturally occurring substances and recipes. These form the basis for many centuries of writing about drugs. There's another connection here to the Aristotelians, since drugs were often made of plants, and Aristotle's student Theophrastus literally wrote the book on that subject. Also important throughout classical medicine was the idea that doctors should not only heal the sick and wounded, but help the healthy to stay healthy by prescribing the right diet and exercise regime. All of which raises a pressing question. Whether the goal is healing the sick, or preserving health, how should doctors go about discovering the right therapies? This question provoked one of the most interesting debates in the ancient philosophy of science. Different doctors had very different ideas about how we make progress in our knowledge of medicine, and these ideas often interacted with, and were inspired by, more general philosophical discussions of knowledge. We know about these debates largely thanks to a figure I've mentioned several times already, Galen. He lived in the 2nd century AD, quite a bit later than the early scientists of Alexandria, but he can provide us with at least one thing that figures like Aristotelius and Herophilus do not. Extensively surviving writings about medicine. And when I say extensive, I mean it. You could start reading Galen right now and not finish until you are ready to be mummified yourself. He is the ancient Greek writer for whom we have the largest surviving body of work, despite the fact that a number of writings have been lost. He was astoundingly prolific, and is the source for most of what we know about pre-Galenic medicine. As with Aristotle, who is a similarly important source for the pre-Zakratics, this is something of a mixed blessing. Both Galen and Aristotle hardly ever report earlier thinkers' ideas without trying to score some point of their own. This makes their testimony unreliable and biased, but no less valuable, given that it is sometimes the only information we have. One of the debates that fascinated Galen was this one I've just mentioned, concerning what one might call medical epistemology. How is it that doctors discover their treatments? In several works on this subject, Galen describes three major so-called sects, the rationalists, the empiricists, and the Methodists. Two weeks ago, we already met an empiricist, the great skeptic philosopher Sextus Empiricus. As I mentioned, the empiricus part refers to the fact that he was an empiricist doctor. He was a rough contemporary of Galen, but the empiricist sect went back much further than either of them. It was founded in the mid-third century BC by a student of Herophilus named Philinus, who was followed by another doctor, Serapion. As their name implies, these empiricists believed that the source of our medical knowledge is experience, in Greek empyrea. Though it may seem obvious that experience should play an important role in developing medical theories, the empiricists put the point in a way that was controversial indeed. They claimed that we need only use experience, and that in fact no theory is required. Opposed to them were the so-called rationalists, sometimes referred to as dogmatists. They did not necessarily reject the importance of experience entirely, but insisted that any doctor worthy of the title would also have an understanding of the underlying causes of illness and health. The humoral account, already mentioned, would be a classic case of a rationalist theory. A disease like melancholy, for instance, would be explained by an excess of black bile, which could be treated by combating that imbalance. Since black bile is cold, one might apply warming drugs in hopes of a cure. At first blush, it seems that the rationalists and empiricists would thus have offered very different treatments. But Galen explicitly says that they did not. Rather, they would prescribe the same drugs and other treatments, recommend the same kind of diet, and so on. The disagreement rather concerned method and justification. The empiricists would thus recommend the same drug, not because it is warming and thus counterbalances the cold of black bile, but simply because in our experience, people who have presented these sorts of symptoms tended to recover after ingesting this drug. So, whereas the rationalists point to hidden causes and underlying principles, the empiricists stick to what is readily observable, or as they put it, evidence. They try to match symptoms that are evident to the senses with remedies that have been observed to relieve those symptoms in the past. The rationalists complain that it is hard to see, in that case, how anyone could ever make any progress in medicine. In fact, there seems to be a paradox lurking here. We are just following what our predecessors did, but how did they arrive at the remedies they found effective? The empiricists offered several answers to this question. For one thing, useful therapies can be discovered by good luck. Also, one may have a sudden inspiration or hunch about something that could work, and try it out. If it is successful, it can be tried again in the future, and may ultimately prove itself a reliable therapy. Finally, the empiricists speak of a method they call transition to the similar. For instance, we may observe that it helps to apply cold to a thigh which is red and swollen, we might then naturally apply cold to a red and swollen arm. The empiricists' disdain for rationalist theories may seem, from our perspective, to have been well-founded. After all, rationalist explanations, such as the humoral theory, were not in fact true. On the other hand, the empiricists rejected much of what we would recognize as good scientific practice. For instance, they denied the need for anatomical research, repeating their mantra that one should attend to what is evident, which does not include things hidden inside the body. Rather optimistically, they suggested that anything useful to be learned about anatomy had probably already been discovered. We now think of natural sciences, like medicine, as empirical, but this first group of thinkers to use the name empiricists were not interested in discovering underlying causes, as we assume science should do. Indeed, there is a family resemblance between medical empiricism and ancient skepticism. Galen compares the empiricists to the original skeptic, Pyro, and I don't need to repeat yet again that Sextus was an empiricist doctor. For the same reasons, the empiricists stand in contrast to the pioneers of Alexandria. For instance, Eris Sistertus once weighed a bird, stopped feeding it for some time, then weighed it again, along with the excrement it had produced in the meantime. He found that this total weight at the end was less than the bird's original weight, showing that some matter had been lost through invisible emanations from the bird's body. This was careful observation, but in the service of a rationalist theory about causes. Galen agreed with Eris Sistertus and the rationalists that a good doctor should understand the underlying causes of things. For Galen, this often meant attending to the purposes of nature. He followed Aristotle in believing that natural things, like bodily organs, have goal-directed functions. In a lengthy work called On Natural Faculties, Galen argued against Eris Sistertus that bodily organs do not work like mechanical parts—filters, bellows, and pumps—but have innate powers, for instance the power to digest food or expel waste. Another treatise, On the Usefulness of the Parts, extols the well-designed functioning of all bodily organs. When we study the hidden causes of health and disease, Galen argued, we are uncovering the exquisite design of nature itself. For him, nature is itself a sort of craftsman, and in this respect like the divine craftsman, or demiurge, described by his hero Plato in the dialogue Timaeus. Galen also accepts other distinctively rationalist ideas, for instance the humoral theory, never missing a chance to remind us that this theory goes back to his other hero Hippocrates. On the other hand, Galen wants to emphasize that he is not simply a rationalist. A good doctor must also pay close attention to experience, both the findings of others and what one can discover for oneself. Thus, he suggests that the best method is a kind of fusion of the rationalist and empiricist approaches. By contrast, he finds nothing to value in a third sect of doctors, the Methodists. We're particularly unfortunate in being so dependent on Galen for our knowledge of this sect. He can barely mention the Methodists without resorting immediately to mockery and invective, so his evidence is even more biased than usual. Still, it is clear that the method of the Methodists did make a difference with respect to their actual medical practice. To understand why, we need to turn to the grandfather of this third sect, Asclepiodes. He came to Rome from his home Bithynia in modern-day Turkey in the late 2nd century BC. Like Greek philosophers who turned up in Rome at about this time, he had a great impact. An admirer of Asclepiodes was a court doctor under Augustus, for instance. His medical theory is reminiscent of ancient atomism and resonates with Epicurean descriptions of the human body, such as we find in Lucretius. For Asclepiodes, the body is made up of tiny particles. Disease results when these particles cluster in such a way as to block appropriate motions in the body or scatter so that things flow too freely. Other authors followed Asclepiodes in thinking that this theory was preferable to the four-humor idea of the Hippocratic and Aristotelian traditions. In particular, two figures of the 1st century BC, Themeson and Thessalus, adopted the ideas of Asclepiodes in a radically simplified form. This was Methodism. According to the Methodists, all bodily disorders come about because of one of three conditions, either a blockage, a flux, or a mixture of blockage and flux. They identified a limited number of certain so-called commonalities, specific types of blockages or fluxes that were revealed by evident signs like inflammation or a leaking of fluid like pus or phlegm. Because the range of commonalities they recognized was relatively small, they thought it was easy to remember both them and the appropriate remedy in each case. Gellin is outraged to report that the Methodists believed anyone can learn to be a doctor in just a few months. Reversing a famous Hippocratic aphorism, they declared that life is long, but the art is short. One of the things that most annoys Gellin about Methodism is their refusal to offer medical therapies that are tailored to each patient. Gellin was, after all, a doctor for the rich and powerful. I've mentioned previously that he attended Marcus Aurelius and his son, and part of his professional self-image was that his patients would receive a kind of bespoke treatment, one just right for their bodily condition, their location, the season of the year, and so on. This is another idea he finds in Hippocrates, in such texts as Ayres, Waters, Places, which studies the effect of one's environment on one's health. It was embraced by both rationalists and empiricists, who would have taken account of a patient's circumstances in considering which previous experiences would be relevant to them. Only the Methodists had neither time for, nor interest in, such niceties. Perhaps the everyday medicine dispensed on the streets and in the houses of Roman society was more like what the Methodists offered than what Gellin could promise, but Gellin would triumph as far as the future of medical literature was concerned. One reason his works are so voluminously preserved is that he was so cherished by later doctors. Gellin was almost synonymous with medicine in the medieval Greek, Latin, and Arabic traditions, like Aristotle with philosophy. And for good reason. Gellin not only fused together the methods of the various sects into a more sophisticated hybrid, but drew connections between medicine and philosophy in a way that was unprecedented. He was also a master of medical techniques, such as pharmacology, surgery, and dissection. These skills enabled him to prove once and for all that the Stoics and Aristotelians were wrong. Our soul's ruling faculty is not in the heart, but in the brain. How did he do this, and where exactly does he fit in the ancient philosophical tradition? To find out, I'll be interviewing one of the world's leading experts on philosophy in Gellin. It would make me sick if you missed my discussion with Jim Hankinson. Next time on The History of Philosophy Without Any Gaps.