76 - R.J. Hankinson on Galen

Jim Hankinson, a leading expert on philosophical themes in Galen, joins Peter to discuss this greatest doctor of the ancient world.

• R.J. Hankinson, "Galen and the Best of all Possible Worlds," Classical Quarterly 39 (1989), 206-27.

• R.J. Hankinson, Galen. On the Therapeutic Method. Books I and II (Oxford: 1991).

• R.J. Hankinson, Galen. On Antecedent Causes (Cambridge: 1998).

• R.J. Hankinson (ed.), The Cambridge Companion to Galen (Cambridge: 2008).

• R. J. Hankinson, "Galen on the Limitations of Knowledge," in Galen and the World of Knowledge, ed. C. Gill, T. Whitmarsh and J. Wilkins (Cambridge:  2009), 206-42.

Note: this transcription was produced by automatic voice recognition software. It has been corrected by hand, but may still contain errors. We are very grateful to Tim Wittenborg for his production of the automated transcripts and for the efforts of a team of volunteer listeners who corrected the texts.

Peter Adamson: Perhaps we could just start by talking a little bit about who Galen was and his personality, which was rather interesting.

R.J. Hankinson: Yes, I suppose it was. We know quite a lot about Galen because he wrote voluminously and wrote a great deal about himself, always in a flattering light, as autobiographers typically will. He was born in 129 AD and died sometime early in the third century at the age of probably about 85. We don't know precisely when he died, but that's almost certainly when he did. He had a very long and enormously productive life. Roughly 10% of all that survives in Greek from classical and later times up to early medieval times is in fact the writings of Galen. Far more of Galen survives than anybody else and a great deal has been lost. There are a number of reasons for both of those facts. He was born in Asia Minor. He came from a relatively wealthy family, had a conventional upper-class education, which involved him traveling to various places and studying with leading philosophers of his time. First of all, in Pergamon, where he was born, and then in Smyrna, and then in Alexandria, which was still a major center of learning, particularly of medical learning. He moved to Rome for the first time in his early 30s, stayed there for three years, went back home, we're not quite sure why, although there's evidence that he left Rome in rather a hurry, and returned to Rome at the age of about nearly 40, and he stayed there as far as we know for the rest of his life. He moved in elevated circles. He became first of all one of the official physicians to the emperor, Marcus Aurelius's son Commodus, and then a physician to the emperor himself. He records numerous successful cures of Rome's upper crust in the 160s and 170s.

Peter Adamson: Unfortunately, Commodus survived his medical care.

R.J. Hankinson: Yes, yes, yes. History has some reason to regret that, I think. Galen is notably quiet about Commodus. He says very, very little about him anywhere in his surviving writings, which suggests that he wanted to really rather push that association under the rug for fairly obvious reasons.

Peter Adamson: Yeah, you can't blame him for that.

R.J. Hankinson: No, you couldn’t.

Peter Adamson: But we're going to be talking today not so much about his relationship to these historical figures, but about Galen and philosophy. And I guess Galen might be rather surprised to be included in a series of podcasts on the history of philosophy, because obviously he's not thought of as a philosopher. He's thought of as this giant in the history of medicine. And in fact, it's not just that he doesn't say anything about philosophy. He's sometimes really explicitly skeptical about philosophy. So he talks about topics like the nature of the soul or the nature of God, and says that he has nothing to say about these issues, or he hasn't gotten together a kind of dogmatic position about them. Why do you think he was so skeptical about those issues? And do you think that he would sort of mind being treated as a philosopher in some sense?

R.J. Hankinson: Oh, no, I don't think he would have minded at all. In fact, I think he would have welcomed it. I think for all the same reasons that Galileo insisted on being given the title court philosopher when he moved to Florence in 1610. But no, he did certainly did think of himself as a philosopher. He wrote two books about his own books, in one of which he categorizes the books that he wrote into a variety of different categories, some purely medical. But a great many of them are explicitly concerned with philosophers and philosophical questions, not least logic, in which he was extremely interested and quite influential, but also works on Plato's moral philosophy, for instance, which haven't survived. And he certainly did think of himself as a philosopher; he wrote a very short piece which does survive called “The Best Doctor is Also a Philosopher.” And he means that quite literally. He thinks that unless you cultivate the philosophical skills of logic, physics in the sense of natural science, and ethics, you can't hope to become a successful practical or theoretical doctor. And as I say, he takes that very seriously. But you're right, of course, that he does evince considerable skepticism about what he would certainly have thought of as speculative metaphysics. Indeed, he uses the term theoretical, theoreticae, to mean something rather like speculative in the derogatory sense. These are certain sorts of questions, as you mentioned, the nature of God, not God's existence – he's perfectly convinced that the universe is run by a benevolent deity. And so not the soul's existence, which of course is a matter of triviality in Greek, but questions as to what these things actually are, their substance or essence. Galen thinks those questions can't reasonably hope for a solution, which is of a sort that meets his relatively rigorous criteria. So his skepticism, if you want to put it that way, about metaphysical questions, is derived from a serious methodological commitment, which can be expressed in roughly the following way. Galen is certainly not averse to theoretical constructions in science and in medicine and so on, but he's absolutely convinced that for them to have any hope of validity, they have to be answerable to what Quine would have called the tribunal of experience. That's to say, they have to be empirically testable. And his main reason for rejecting what he takes to be hopelessly speculative metaphysics is there's just no way of answering the question empirically. And one of the questions that he relegates to this no-man's land of speculative metaphysics is the question much debated among ancient philosophers as to whether there's a void, and in particular, whether there's a void outside the ordinary structure of the universe, which is a view held by the Stoics. And Galen says, well, there's no way we can tell that unless you send somebody to the edge of the universe and they take a look at it. And until you can do that, you might as well just stop talking about these things.

Peter Adamson: You have to apply for funding.

R.J. Hankinson: Exactly, yes. That's exactly right. So there are a number of questions which he just thinks are empirically unanswerable, and because empirically unanswerable, uninteresting.

Peter Adamson: I guess that would make sense of the fact that although he doesn't have views about the metaphysical nature of the soul, for example, he does have views about the soul insofar as the soul is empirically detectable. So he has another work called something like that, the powers of the soul are dependent on the mixtures of the body.

R.J. Hankinson: That's right.

Peter Adamson: And I guess his idea there would be, although you can't tell for sure what the soul is by looking at people or animals, you can tell that what the soul does somehow depends on the body, because for example, when people get drunk, you can see that it affects their psychological capacities. Is that basically the idea?

R.J. Hankinson: Yes, well, that's one of his key examples, of course. The impact of various psychotropics. And also, even more generally, he thinks that the sort of diet, the sort of regimen you adopt has an effect on, for instance, how bad-tempered you might be. And he thinks this is determinable. And as a result of that, at the very least, he's committed to the view that certain mental attributes are at the very least influenced by and may possibly be reducible too, in some sense – although he's very careful not to express any firm view on that – to physiological features of the body, roughly speaking, your internal makeup, the makeup that he conceptualizes in terms of the four humors, which are typologically linked with the four elements of Greek four-elements theory and with the four basic qualities, hot, cold, wet, and dry, which all looks pretty theoretical in a certain sense it is, but Galen himself is quite convinced that he had empirical, good empirical grounds for supposing that this was in fact the case, and that psychological properties were dependent upon or at the very least heavily influenced by states of physiology.

Peter Adamson: And when he says that the best doctor has to be a philosopher, is that because as a philosopher that you find out things like the four-element theory and that that underlies what the doctor is doing?

R.J. Hankinson: Yes, that's certainly the reason why he thinks you have to know a good deal about physics, about natural philosophy. He does think that you can be a successful practicing doctor with, roughly speaking, empirical knowledge, but he thinks you can't really understand what's going on and hence hope to make advances both in theoretical understanding and by extension in treatment, unless you have a thorough understanding of the physical basis of the body and hence of what can go wrong with it. So that is the reason why he thinks that you need to have a background in physics. He thinks you need to have logic for two reasons, so that you can understand consequence, in other words, so that you can recognize and construct valid arguments, and also equally importantly, perhaps more importantly, so that you can unmask the falsehoods of the charlatans.

Peter Adamson: Of which there were plenty, according to Galen.

R.J. Hankinson: Of which almost everybody other than him was guilty of, according to Galen. And finally ethics, he says, a rather splendid passage that you can't possibly hope to make any serious advance in matters like this unless you're extremely hardworking, industrious, he uses the word philoponus, and you can't have that virtue if your life is devoted to pleasures of various sorts, if you are overly addicted, as he puts it, to food, drink and sex, so you need to have the philosophical virtue of ethical restraint in order to have enough time to actually do a decent job of things.

Peter Adamson: Maybe we could then move on to one of the advances he did make, which concerns human anatomy and in fact animal anatomy more generally. I think this is maybe his greatest achievement in medicine, although maybe you'll disagree with me about that, and this is his demonstration that what the Stoics had called the ruling faculty – so the part of your soul that is in charge of your movements, your thoughts, your desires, things like that – that that's seated in the brain rather than the heart. So can you talk a bit about how he showed this?

R.J. Hankinson: Well yes, and I think you're right to say that, that's certainly one and probably the greatest of all of his achievements and a lasting one at that. Of course this has been a long-standing dispute, both among doctors and among philosophers, as to the location of the ruling faculty, as you say, the seat of consciousness and the part that's responsible for voluntary motions and things of that sort. Of course, Galen is by no means the first person to say that it rests in the brain, it's already there in Plato, or at least the rational soul is there in Plato.

Peter Adamson: And he thought Hippocrates thought so.

R.J. Hankinson: And he thought Hippocrates thought so too. Of course the Hippocratic question is a major question.

Peter Adamson: You mean who wrote the Hippocratic treatises?

R.J. Hankinson: Who wrote the Hippocratic treatises, whether any of them are attributable to historical Hippocrates or not. Galen had very strong views about that, he wrote extensive commentaries on Hippocrates, he saw himself as being the true heir to Hippocrates. And of course, partly as a result of his own predilections, he picks and chooses among the texts that survived under Hippocrates's names: this one clearly can't be genuine because it has the wrong views, and so on. So he does choose texts of Hippocrates which do lean towards, and in some cases actively endorse, encephalocentrism, the idea that the brain is the seat of the ruling faculty. But of course Aristotle famously had thought that the heart was, as indeed did the Stoics. Now the crucial interim discovery here was made in Alexandria in the third century BC by a great doctor called Herophilus, who was the first to distinguish between the motor and the sensory nervous system on the basis of detailed anatomical investigation and probably also vivisection and very likely human vivisection too. And that's of course an enormous breakthrough. And Herophilus was committed to the view that the brain was the center of these things. So Galen isn't an innovator in that sense, but in his first visit to Rome, when he was trying to make a name for himself, he undertook a series of extremely high-profile public demonstrations of animal vivisection in which he undertook to show various things by means of careful sectioning of the spinal cord and ligation and severing of various parts of the nervous system. He was able to show, for instance, that various sorts of paralysis are induced by different sections in the spinal column. And most vividly of all, and this is a story he recounts on more than one occasion, Galen was responsible for the discovery of the recurrent laryngeal nerve, that's the nerve that innervates the voice box, and showed by means of a very careful experiment where you lay open the nerve in the neck and are able to pinch it off. If you pinch it off, the animal that you're working on, typically an unfortunate pig – Galen says pigs are very good for this sort of thing because they have very loud voices, and what's more, their expressions don't show pain so it's not as upsetting to the audience as using monkeys is, for instance.

Peter Adamson: But it's upsetting to the pig.

R.J. Hankinson: It's pretty upsetting to the pig as well as one could tell. And you just pinch off this very tiny nerve and suddenly the pig stops screaming and then you let it go again and it starts screaming. And of course that shows something, Galen thought quite rightly, very striking about neural transmission. But most importantly, he thought that, and this is of course part of the empirical side of the demonstration of the centrality of the brain, he could also show, simply by dissection, that the nervous system starts from and ramifies from the cortex. That it branches out, and he uses the imagery of branching of trees and so on. And he just thinks that it's obvious that what something ramifies from is going to be the center of control of that system, if there is one. So that's roughly why he thinks he's got something more than a viable hypothesis, why he thinks he's got something close to a demonstration or a proof. And he uses the language of demonstration.

Peter Adamson: And of course all of that obeys the empirical strictures that you were talking about before.

R.J. Hankinson: Exactly, yes.

Peter Adamson: There is something kind of more complicated here though, right, which is that as a follower of Plato, he recognises a three-part soul. So there's the rational soul, there's the spirited soul, and there's the appetitive or desiring soul. And he doesn't think that all three of those faculties or parts of the soul are seated in the brain, does he?

R.J. Hankinson: No, he doesn't. He adopts a version of Plato's tripartite view of the soul. So he thinks that, as you say, the spirited part is located in the heart. And in some sense the appetites are centralized in the liver, although he doesn't think of the liver as being, for instance, an alternative seat of consciousness. It's not that when you feel hungry and you recognise the fact that you feel hungry, that's all going on in the liver. There's something going on in the liver, roughly speaking the basic nutritive drive. It's being registered as a conscious fact in the brain. Now his reasons for thinking this, these are quite interesting too. In the course of a long work called “On the Doctrines of Hippocrates and Plato,” in which he tries to show both that Plato and Hippocrates had gotten things pretty much right about all important things and hence were in agreement with one another, he allows explicitly that he doesn't have a proof of the same degree of convincingness for the location of the appetites in the liver, as he does for the location of the center of voluntary control that's in the brain, because he can't show on the basis of telling experiments and interventions that you can intercept, as it were, the appropriate messages.

Peter Adamson: Squeeze my liver, I stop being hungry.

R.J. Hankinson: Well, the equivalent would be doing something with the system of veins, which of course you can do all sorts of things with, but they don't seem to have any direct effect on whether the animal's hungry or not.

Peter Adamson: Or angry.

R.J. Hankinson: No, that would be the arterial system, of course, from the heart. So he's well aware that he's on much shakier ground there, which I think does him some credit. He doesn't make the evidently false claim that he can demonstrate in some sense that the liver is responsible for desires. He takes a rather more roundabout route, and it would take too long to go into how he tries to do it. But I think it's intriguing in the sense that one sort of axiom, which I vaguely alluded to in connection with the nervous system, is the idea that if some organ is the origin of a ramifying system, then there's reason to suppose that it is in some sense in control of what goes on in that system. And he knew on the basis of his very extensive and detailed anatomical knowledge that the system of veins, as opposed to the arteries, really does look as though it branches out from the liver, from the vena cava and so on. And equally, the arterial system branches out from the aorta and appears to start in the heart. Well, you've got the pulmonary system and so on, which is a bit of an issue, but in general that's the way things look. And for this reason, he thought of these as being two separate systems, each being responsible for the transmission of different sorts of stuff into the body. And in particular, the venous system is responsible for the transmission of metabolized nutrition. That's really what it does. And that's the fundamental sense in which he thinks that the liver is the location of desires, because it's the liver, as it were, that responds to the need for nutrition and for pushing nutrition around. So it's almost a kind of behavioral criterion, if you like.

Peter Adamson: Of course, he's taking desire for food and drink as being some kind of primary example of desire.

R.J. Hankinson: Exactly, yes. And fundamentally somatic, even though, of course, they have, as I mentioned before, obviously, conscious correlates. You know you feel hungry and things like that.

Peter Adamson: I guess one thing that really struck Galen in all of these experiments and investigations is how cunningly put together animal bodies and human bodies are. And so he became very convinced that animals, and maybe also plants and other things in the world, but certainly the things he was dealing with as a doctor, were what we might say are teleologically put together. In other words, they seem to be purposive, they seem to be put together with some kind of final end in mind. And this is interesting because although he thought of himself as a follower of Plato and Hippocrates, here we seem to have a really important point of agreement between him and Aristotle. So can you say something about how his teleological commitments relate to Aristotle's philosophy of nature?

R.J. Hankinson: Yes. Galen was a great admirer of Aristotle. He thinks that he's one of the great men of the past, although seriously and culpably mistaken about the location of mental activity and so on. Although as he says, well, it's not really Aristotle's fault because they haven't done enough anatomy then to really know these things. His people nowadays saying that sort of thing, he says, are completely...

Peter Adamson: Stoics, for example.

R.J. Hankinson: Stoics and of course, Peripatetics as well – Aristotelians, of whom there are quite a large number around at the time. These people are just being willfully ignorant, he thinks. Yes, the relationship with Aristotle's teleology is, I think, quite interesting, because as I say, he's a great admirer of Aristotle. He quotes extensively from Aristotle's biology, in particular Parts of Animals, as you might expect, which is a text about, among other things, the teleological organization of animal structures. In detail, if you like, the detailed structure of Galen's teleological account of biological structures is very Aristotelian, although he goes a good deal further than Aristotle in some quite interesting ways. I may have to say something about that in a moment. But the overall inspiration is Platonic because Galen is quite convinced that the universe is under the control of, and indeed the structural result of, direct intervention by a creator god, who he calls in obvious imitation of Plato, the demiurge, the artisan, creator god. Of course, there's no trace of that whatsoever in Aristotle. His reasons for thinking that are basically design-argument reasons. He thinks that, and of course this is a view that was held in the 17th, 18th, and early 19th centuries, that the more closely you look at the structures of things, the more obvious it is that these can't be the result of chance or can't be the result of some kind of strange agglomeration of useful characteristics because the more closely you look, the more finely tuned the mechanisms seem to be. So he's a Platonist in that sense, but as I said, the fine structure is very much Aristotelian with additions. But since he's committed to the view that there is a creator god of enormous intelligence and benevolence, he's much more concerned than Aristotle is to try to give an adaptive answer to the question why certain structures are in the body. So where Aristotle of course famously and very usefully will say sometimes, well a particular organ isn't there for any reason at all, it's just a material consequence of other things which do have teleological purposes, Galen's inclined to think that that can't be the case. No serious craftsman would have done that kind of thing.

Peter Adamson: So something like hair, for example.

R.J. Hankinson: Exactly, yes. He produces a teleological account of why it's a very good thing to have eyelashes, among other things. Eyebrows stop the sweat dripping into your eyes, which is a good thing, and eyelashes stop small insects flying in. And he also argues that it's clearly right and clearly beneficial and clearly teleologically well organized for men to have facial hair but women not to. And that's because women work indoors so they don't need protection from the elements in the same way. He also says having a large and impressive beard would lend an undue air of augustness to the female physiognomy, something that would not be in accord with their essentially frivolous styles.

Peter Adamson: So beards make one look dignified.

R.J. Hankinson: Dignified and philosophical.

Peter Adamson: This might be an appropriate time to tell the listeners that both Jim and I have beards.

R.J. Hankinson: Yes indeed. And I'm pretty sure Galen must have had one too.

Peter Adamson: Or he wouldn't have said that.

R.J. Hankinson: He wouldn't have said that, yes, exactly.

Peter Adamson: So maybe one last question just quickly because we're running out of time. I think one interesting thing about Galen is that he lives at a time where there's a lot going on in the history of Platonism and he seems to be very unusual as a Platonist. So while other people are coming up with these highly metaphysical, highly speculative versions of Platonism, he has this, what you might think of as a down-to-earth kind of Platonism, which draws more on the Timaeus arguably than other dialogues of Plato but certainly draws on the Republic as well. And also tries to weave together Plato with Hippocrates. So is there anything you can say to explain that? Is it just because he was a doctor and so he came at Plato from a kind of medical direction rather than a speculative metaphysical direction?

R.J. Hankinson: Well I think it's partly that. I think he does tell us something about his philosophical education. As I said earlier, he studied with leading representatives of all the major schools, Stoic, Epicurean, Aristotelian and Platonist, and found all of them wanting in some degree. Found them in particular all to be too closely wedded to the doctrines of the master. And in a number of places he says, I belong to no sect, I'm not a sectarian. And indeed you shouldn't be a sectarian because it's a sort of servile attitude to take. That's not to say that the great men of the past haven't said things that were right. But you shouldn't just suppose that they were right because they were said by great men of the past. And so in that sense he's a sort of eclectic. He thinks, he even finds on occasion things to be said in favor of some Stoic views, in particular on logic, although only up to a point. He's almost universally dismissive of Epicureanism because he thinks atomism is a non-starter as a physical doctrine.

Peter Adamson: And he doesn't like their rejection of teleology either.

R.J. Hankinson: And he doesn't like rejection of teleology either. So I think he is, he's certainly not a representative Platonist. And it's certainly a mistake in a sense to label him I think as a Platonist if by that you think of something like an orthodox middle Platonist of the early imperial period, someone like Alcinous or something like that. So because of the strict rejection of speculation. And because he's not interested in system-building in the way that the Platonists of the time and of course in succeeding centuries were almost obsessively interested in building a system that will somehow include everything within it in some grand structural scheme. Galen's not interested in that at all. As we've said he does think that the universe is under the control of a providential god, but he thinks that that's empirically determinable. And he doesn't think you can say anything much more about God than that. God's substance is going to be a mystery. Just in the same way, as you started out by saying, the substance or essence or real nature, if you like, of the soul is also a mystery. He thinks that it's clearly materially effectable. For that reason it's quite likely to be material, but he thinks you can't rule out the Platonist view that the rational soul is immaterial and immortal. He just thinks you can't establish it either. And so you might as well not bother.

Peter Adamson: And in fact these are precisely the other figures I'm going to be getting onto in the next episode but first let me thank Jim very much for coming on and showing us that the best ancient doctor was also a philosopher.