← History of Philosophy Without Any Gaps
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- [00:12]
A
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@historyofphilosophy.net Today's episode will be an interview on medicine and science in Cartesianism with Gideon Manning, who is associate professor of history of Medicine and Humanities at the Cedars Sinai Medical center in Los Angeles. Hello, Gideon.
- [00:35]
B
Hi, Peter. Longtime admirer of the podcast. I'm glad to be here.
- [00:38]
A
Thank you very much. Nice to have you. Here in Jimich, we're going to be talking about medicine and Cartesianism in general, but let's start with Descartes himself. In a quote that you like to mention when you're writing about medicine, Descartes, he says, the preservation of health has always been the principal end of my studies, which sounds very emphatic. So can you elaborate on that?
- [00:59]
B
Sure, I'd be glad to. And it's true, I do like the site that. Although in all honesty, I think it's slightly a bit of an overstatement, I should say, especially when you start to try and look for that kind of content in Descartes. But maybe it'll help to give a broader view of medicine and philosophy in the period and then locate Descartes there and then say something more about his actual views about medicine. And when I think about medicine in the early modern period, I think the thing to emphasize is that true knowledge starts to become useful knowledge in the early modern period, at least in many quarters. It's not that it's philosophy that is. It's not that it's no longer about consolation or contemplation or beatitude or preparation for death. It remains all of those things. But one of the measures of true knowledge in the early modern period seems to become usefulness. The rubber hitting the road in terms of public goods, and in many cases, reclaiming our health when it's lost, preserving our health and even extending the length of our lives. Descartes, one of these people who really buys into that idea. Starting in 1637, his first publication, the Discourse on Method, Discourse 6, ends with a call to master nature, that true knowledge will do that for us, that he's going to provide that, and that the route to making us wiser and better able to deal with the world will be through medicine. But not the medicine he knew, not the medicine of his day, the medicine he plans to deliver to us. That starts in 1637. The quote you read comes from a letter to the Marquis of Newcastle in 1645, not quite 10 years later. But if you look for Descartes medical views. So now, stepping back from this more general commitment that Descartes seems to have about useful knowledge, if you look at his medical views, they find expression in a host of different ways. They find expression in his correspondence, where he indicates, for example, in 1639, when he is writing to Father Mersenne, his friend and confidant, he says that he's been working on medical issues and conducting anatomies for some 11 years. So the earliest evidence we have of Descartes interest in anatomical issues and medical questions starts around 1629, but it really does extend to the end of his life in 1650. And it includes these peaks of interest where there's more evidence of activity than at other times. For example, in 1633, at the moment he abandons one of his most systematic works of natural philosophy, he's approached by the University of Bologna to assume a position in theoretical medicine on their faculty. And that speaks to the kind of interest and the perception of him with respect to medicine. But he also, in his correspondence, offers medical advice, he tries to solve a host of medical problems he identifies. And if you think of one of the most famous versions of philosophy that he presents in the letter preface to the French edition of the Principles of philosophy in 1647, he presents Philosophy like a tree. The roots, metaphysics, the trunk, physics. And then the primary branches are mechanics, medicine and morals. It's right there really all along in his mature period, and I would even say it extends to an earlier period in his thinking.
- [04:38]
A
Speaking of mechanics and also of anatomy, which you've both mentioned, one of the first things that leaps to mind in terms of trying to connect his medicine to his philosophy, how he would have thought the human body works and how he would have integrated that into his mechanistic understanding of nature. How does he do that with respect to, for example, how specific organs work.
- [04:59]
B
Like the heart or the brain? That's a great question. My own view about this is that Descartes really becomes the Descartes we know, this extremely ambitious natural philosopher with a program that extends to all of nature. That happens when he's writing the Treatise on Man, which is the 18th chapter of Le Monde. And that's a work that starts in 1630 and is abandoned, as I mentioned in passing, in 1633. The reason that work is so important is because Descartes turns his attention from technical questions in mathematics and specific issues with respect to light. And its transmission and astronomical phenomena to human beings and to animals and really to living things more generally. And when he does that, the approach seems to involve a supposition. And then pushing that supposition as far as he possibly can. So the supposition is that the body is like a machine. And he's going to try and explain as much as he possibly can in mechanical terms. So drawn on the language of engineering and mechanics. And in doing that, anatomy is just one of the ways that he exploits the knowledge of his time and then expands on the mechanical character of the body and its functions. So you mentioned the heart, and this is actually a special one for Descartes. So he reads Harvey's work, which is published in 1628, about the motion of the heart and the circulation of the blood. And though I don't think he needs Harvey for his project, he sees it as a fantastic test case for the strategy he wants to adopt and the supposition he wants to exploit. And he develops an account of cardiac motion that differs from Harvey and one that Descartes very proud of and defends throughout his life. Come the 16, late 1640s, he begins work on something that is eventually published called the Description of the Human Body. And there he says that without a good account of the motion of the heart, you can't really know anything in medicine, in theoretical medicine. So that account is, I guess, I would say, mechanical. It's a little gray at the margins. But the idea is that you're going to be able to explain what the body does, how the heart pumps blood, the motion of that blood through the body and even its contribution to our cognitive activity, at least to some extent, purely in mechanical terms, like a hydraulic system, basically. I think that's exactly right. The tendency is to think of Descartes as thinking of the body as a machine. And then we imagine these kinematic machines. But in fact, it's a lot of blood and guts. It really is a vascular system with things moving through it, blood, animal spirits, material substances. And that's true of the cardiovascular system. But also I would try to suggest the brain and the nerves as well are vascular systems.
- [08:14]
A
So he thinks there's fluid running through the nerves.
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B
Right.
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A
So it's basically just like the heart pumping blood through the body. The brain is pumping something. Nervous system.
- [08:23]
B
This is a good question. Right. So this issue about whether or not the blood or the brain pumps the way the heart pumps, it's not resolved, I think, until much later, and thanks to not Descartes himself, but some of his Cartesian physicians like Regius Henricius Regius, who is a disciple initially, but then goes on to get Descartes into real problems in Utrecht where he taught. And that led to Descartes first condemnation, but leaving that issue for another podcast. The real point in my mind about the brain and the nerves is that it is like a cardiovascular system and it actually draws on, by analogy, much of what Descartes learns, not only from our view, but from reading and his own experimental work with living things.
- [09:11]
A
Actually, there's something else I wanted to ask you about, and this might be a bit of an invitation to speculate, so I apologize for that, but it's not so clear to me from what you were just saying, whether the idea is that he's doing this in anatomical research and he's thinking, oh, this is all basically mechanical, this is a hydraulic system, so therefore I should be a mechanist in my natural philosophy. Or is it more that he has mechanist presuppositions in his natural philosophy and he just forces all the observations to fit? In other words, what's doing the work? Is it the natural philosophy, mechanism theory, or is it the anatomy?
- [09:49]
B
I think the least kind interpretation of Descartes, and one that has a long history, is that he is effectively committed to mechanism and these preconceived ideas about what has to be vindicated in medicine and in anatomy and physiology more generally. And then he just starts hammering every square peg he can find into the round hole. But I think that's unfair. It's unfair for a number of reasons, not least because Descartes is engaged himself in anatomical dissection. He's interested in the causal implications of his anatomical experiments, vivisections in particular. He is trying to substantiate speculation, and certainly it is one. And he calls it a supposition, in fact fact, that the body could be a machine. And remember what he's pushing against. He's pushing against an entire tradition, whether Aristotelian. So the two big names in the period that finds life to be something more than a material phenomenon. If he couldn't explain anything mechanically, the supposition would have very little value and it would convince no one. We could debate about the extent to which his explanations are successful, and I think some are more successful than others. But to my mind, we have to think of him as engaged in a kind of back and forth. It's about learning from the bodies he experiments with. It's about reading the books of anatomy and medicine more generally, and extracting and drawing on novel facts of the period, like the circulation of the blood. And it's about commitments that come in a sort of more unified way from his natural philosophy. If I could just give one specific example that I have in mind. At one point, when he's disputing with someone about the movement of the heart and the circulation of the blood, a physician named Plumpius, who's a fascinating figure in his own right, Descartes appeals to the laws of his mechanics to account for what he expects we would find in. In an experiment about the motion or the pulse, the motion of the arteries. And you can take that as mere hand waving. But I think it's more than that, because I think what Descartes is showing is that the kind of account he would give about the cause of the pulse is consistent with the kind of account he would give of the tides. They actually there's great parity between the two. So does that mean it's just all supposition? I don't think so. I think it means he's appealing to certain epistemic virtues that scientific explanations can have, one of which is unity, another which is simplicity.
- [12:40]
A
Yeah. Okay, so this is kind of cliche, right? That there's the rationalists and the empiricists, and Descartes, the arch rationalist, maybe, along with Spinoza. And he's not like the scientists who.
- [12:53]
B
Overrun Britain like Bacon and the members.
- [12:56]
A
Of the Royal Society, whoever else we might think of. They're empiricists, so they're doing experimental science, whereas Descartes is figuring out everything in his armchair. This is of course, the kind of vision we get from the Meditations.
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B
Right.
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Just thinking in his study.
- [13:12]
B
Right.
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A
But you have a version of Descartes which is much more sensitive to empirical evidence, and presumably he would be willing to revise overall natural theories in response to evidence. Could we go that far?
- [13:26]
B
So I think that's true. It's one of these things where how far can you bend before you break? I think Descartes endurance is a lot greater than the rest of us. He would go much farther in bending before he broke. That much is true. And what that means is he's going to revise fewer of his views than the rest of us. At the same time, though, I think it's the case that Descartes views do change over time. And how do we account for that? It's because of the experiments and the care he took in many parts of his natural philosophy. One point worth, I think, making is that he withheld a number of his views from print because he didn't think he had engaged in enough observation and experiment. That's true of the account of the human being and the principles of philosophy. It's true of the treatise on man, it's true of the description of the human body. These are places where Descartes is aware that you have to resolve issues in experimentally through observation before you can resolve them completely. Even I want to say two other things, if that's okay. Peter. Right. So one thing is that even in a work like the Meditations, by the time you get to Meditation 6, there's a lot of knowledge about the body, for example, that comes in, the phantom limb is mentioned. And that's a phenomenon that had only been clearly articulated for about 50 or 60 years at that point, Right. Descartes is showing his awareness of novel facts as they've been developed in the.
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A
Science and medicine of his time.
- [15:04]
B
But the other point I guess I would make is that Descartes is a figure who can be approached from many different angles and sides. If you think back to the tree of philosophy that he articulates, that actually provides us not fewer than five different ways to approach him. We could approach him through his metaphysics from the roots. And if I think if we do that, then I think we're really going to be prone to see the stark ontology of matter versus the mind or the soul. If we approach him through the physics, that's going to give us a slightly different picture and one that's still pretty austere about the way the world is. But if we approach from the branches, from morals or mechanics or medicine, at that point we're not just talking about bodies, we're talking about full blooded human beings. These are cases where in medicine it's about the health of, yes, the body, but really the human being, with all sorts of teleology included. In mechanics, we're talking about modifying the world for human ends, building artifacts to serve our interests. Teleology again, but the human being, and also in morals, it's not just about the good of the body. So my own tendency is to approach Descartes from the medicine, from the branch, and see what shakes out. And to get back to that first question you had about where medicine fits in things, my sense is, at first glance, you don't see very much of it. It doesn't seem to live up to that statement he made to Newcastle or the one he offers in Discourse six. But I think as you start to scratch the surface, you find it more and more Whether it's in the correspondence where he's giving people medical advice, or in the passions of the soul, where he's developing, finally, his physiology, more detail than in any other work, or whether it's in the meditations, where he's drawing on extensive knowledge that not everybody would have about the body and the nerves.
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A
What about in the other direction? Really talking about what the medicine means for the philosophy, but what about what the philosophy means for actual medical treatments? So if I go to Descartes seeking medical advice, or maybe even the Cartesians in general, because some of them are practicing doctors, right, do they actually have different therapies that they're going to recommend.
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B
Than I would have gotten 30 years.
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A
Earlier from a Galenic doctor? And are those differences grounded in Cartesian philosophy?
- [17:38]
B
So that's a really great question. One thing to always keep in mind in the background is it's not always clear to me how much medicine could do for you prior to the 19th century. There's a serious placebo effect, and maybe people really went to doctors just to be told it's going to be okay in the end, and that was enough. Descartes own strategies here, he picks and chooses from the extant materia Medica tradition around him. But if I can think in terms of his kind of ontology from his physics, right, you're going to imagine that there are going to be maybe three ways to go. There's going to be caring for the body through bodily interventions. Then maybe there's going to be some kind of psychosomatic stuff, right? Caring for the body through the mind. And then finally, there might be some instances in which you care for the mind through the body. Okay. And you would be inclined to think that Descartes is not going to have all of those because the body's a machine and health would seemingly be just about the machine of the body. I think that's actually a very complicated issue. But one thing that we find is that Descartes offers medicine in all these varieties. That is, he advises Blaise Pascal when he sees him get a lot of bed rest and have a lot of soup. It's like the advice your mom would give her, right? When he talks to Princess Elizabeth in their correspondence about her sadness, he encourages her to direct her attention to uplifting, beautiful things and those kind of medical interventions. Chaud has a really big idea about medical care and what it can be like. He took his stand against some traditional techniques of intervention, like phlebotomy. He wasn't a great fan, and on his deathbed he resisted it to the very end.
- [19:38]
A
That's a good call on his part.
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B
Yeah. It turns out YOLO again, you know, stepping back. There are ways in which phlebotomy is not so crazy.
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A
Just maybe we should explain. Phlebotomy is draining blood, right?
- [19:48]
B
That's right. So you do it in specific veins and you know, the sort of. The instrument of the surgeon was the knife, the lance to cut open the body to do this. But I'm not going to defend phlebotomy except to say, look, you knew how much you were getting, you would see how much was taken out. It was in a way a quasi quantitative kind of intervention. And if you had a fever over the long term, it wouldn't be great for you to lose a lot of blood. But if you lose some blood, your blood pressure is going to go down and your fever will actually go down. So there's something to be said for phlebotomy. Not quite what was said in the period.
- [20:26]
A
Okay. Still, folks, do not try this at home. We're not recommending.
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B
Exactly. I remember what I said, you're not going to get a lot of help.
- [20:35]
A
Yeah, let me go back to just a little bit to something you were talking about a moment ago, which is the psychosomatic element of the therapy. I think that's rather surprising because if there's anything Descartes famous for, it's dualism, Right. We actually call it Cartesian dualism. So this idea that the soul and the body are completely different kinds of substances, you would think that would take psychological phenomena completely out of the realm of medicine or natural philosophy as a whole. Is that not the case?
- [21:05]
B
So again, I think that's a complicated question to answer because of the way I read Descartes Medicine, my sense, and also because he incorporates some aspects of the soul. If you think about the principles of philosophy that builds from a kind of first philosophy or metaphysics, general principles of how nature works and what we know and so on, all the way to the human being at the end. There's some incorporation of the soul in natural philosophy, not unlike you would find in a scholastic textbook, traditional Aristotelian stuff. And the fact that Descartes medicine in practice incorporates all these kinds of interventions suggests that he's got a pretty broad minded view that some parts of the mind will really matter in the world and the body will have an impact on it. And I think that's vindicated in all sorts of ways in his psychology. At the same time, the interpretations and choices that Descartes early Readers make as they advocate for his position and develop his view. They limit Descartes in all sorts of ways. I think that the kind of image we have of Descartes now is a byproduct of that early reception. Choices are made by different Cartesian physicians to emphasize one kind of medical intervention over another. Sort of just treating the body alone or emphasizing the role of the mind and controlling the body and vice versa in the case of whether or not the mind is part of nature. So a naturalistic view of the mind. My sense is that moment where Descartes is read as putting the mind into the realm of metaphysics in its entirety, at least in label comes in 1665, when Louis de La Forge is the first one to try to extend Descartes philosophical position by finally writing a work all about the mind, dedicated just to the mind. Treaties on the mind and its functions. And he calls the work a work of metaphysics. To my mind, that's the first time you get that kind of view. But still, even La Forge is interested in mind body interaction. He's a physician. He is responsible for illustrations that are published posthumously with Descartes Treatise on Man. He writes a long commentary to that work. He's still interested in these different kinds of medical interventions.
- [23:43]
A
One of the things that we might also associate with Descartes Cartesian dualism, to give it its official title, is that we gain access to the mind through introspection. So the cogito.
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B
Right.
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A
So I think, therefore I am. So it's me being aware that I'm thinking.
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B
Right.
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A
And what you're saying, I think suggests.
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That there might also be a route.
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A
Via which we could access other people's minds.
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B
Right.
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A
Let's say he's talking to Elizabeth about her problems and he says you need to engage in the following kind of stuff, psychological therapy as well as whatever.
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B
You might need to do to your body.
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A
That certainly suggests that he thinks he knows what's going on in her mind.
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B
Right.
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A
From a third person perspective.
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B
Right.
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A
So would it be fair to say that this kind of scientific approach makes it possible to access other people's minds in a scientific way?
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B
I'm pausing for a long time because I think this is a tricky question to answer.
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A
You keep saying all the questions are tricky.
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B
Maybe it's because Eitan Descartes and both puzzling and fascinating all at once here. I would say that he approaches these issues to the extent he does without much fanfare. He doesn't seem to doubt the existence of other minds at any point. He Seems in fact immune to the kind of skepticism that you just mentioned, being so naturally present, given his views about introspection and our access to ourselves. And that's puzzling. It's puzzling because at some places, for example, in his correspondence with more in the 1640s, more basically says, how do you know children have minds? And for that matter, how do you know anybody does? And it's a concern that basically hits a brick wall with Descartes. Again, look at the meditations. Get the external world back in meditation six, where are other human beings? When do they come back? Maybe meditation three, when God's there. But that's not quite the thing you're talking about.
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A
That's just him and God.
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B
Yes, there's me and God. And so you would think there needs to be a meditation seven that reclaims more of the world and the things we know in it. So I'm not exactly answering your question directly. What I'm saying is that it has an unstable place in Descartes. The first Cartesian to take this idea seriously and to really run with it is Cordur Moi, who sees in the language argument a robust answer to this kind of question about other minds. Descartes, though, as I said, he tends to just not go there. Does medicine provide an avenue? Or does his willingness to think of the mind as part of nature provide an avenue in his assumption? I think all along is that it's a we, not an I. Obviously not in his most skeptical moment, but otherwise, and I'll confess that I've written about this a little bit, which is to say that I have this idea that if the question is, are there Cartesian zombies? Are there these bodies that look like us and act like us, but somehow don't have minds? To the extent Descartes going to have an answer, his answer is going to be that God made bodies, human bodies with minds, and God doesn't deceive us. And God's not going to change the way in which he acts in the world. Part of the evidence of that comes from the Bible. Descartes, he's not going to doubt that. But I think to the extent he's going to have an answer, it's not going to be one that makes him immune to. Are you looking at me thinking right now, Peter, that what I'm saying makes sense? Or are you actually thinking about your lunch? I'm not going to be able to figure out the answer to that. And neither is Descartes, but he's not going to have that kind of global Skepticism about whether or not you're a zombie.
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A
Because God wouldn't do that.
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B
God put me in handful of zombies. Exactly. I don't think God would do that.
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A
And just to double check, what you mean with the language argument that Cordemar uses is just that if other creatures are using language, I can infer from that they must be possessed of a rational soul.
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B
It's that. Yeah, it's the argument that appears in the discourse on method and that gets challenged and developed in different ways over the course of Descartes life. But that's right, that genuine language use is to limit to what we can explain mechanically. So you'll remember I said Descartes engages in a kind of supposition. All right, let's assume bodies really are machines or artifacts of some that act because of the way their parts operate together. How much can I explain? How far can I push that? Given his matter theory, given the kind of machines and artifacts he could draw on as analogies and so on, Descartes went remarkably far, at least to his own satisfaction for sure. But the limit, the place where he thought he could not go was genuine language use that is meaningful, coherent, knowing what you mean when you say it.
- [28:47]
A
Kind of like you cannot build a machine that could.
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B
No machine could do that. It would always be limited to the number of parts it had and the number of inputs and outputs it had. Whereas for him, he thought language was a and reason, I guess you might say, but as expressed through language, it's a universal instrument and no machine could do that. Given the kind of matter theory he had, given the kind of view of machines that he could draw.
- [29:12]
A
Okay, yeah, I guess maybe the jury is still out on whether machines can produce meaningful language.
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B
I think that's right. And I'm not convinced they can. Yeah, not yet.
- [29:22]
A
Okay, that may be going too far in the direction of the future from Descartes. Maybe I could ask you one last thing though, which is to look more at his immediate impact or maybe his impact over the next 150 years. So obviously there's the spread of Cartesianism all across Europe that we're talking about in the podcast as well. How far does his influence reach, at least with respect to medicine? So if we're talking about, say the middle of the 18th century, would it still be fair to talk about Cartesian medicine at that point? Or is it really only something that happens in the 17th century?
- [29:58]
B
Let me talk about his reception starting actually on his death and then move forward from there. I know it's a lot of ground to cover, but I'll try. So I said at the outset that one of the general things to keep in mind is that knowledge is meant to be useful in the 17th century to many, and Descartes fully embraces that idea. So when he dies in 1650 at the age of 54, it was actually a kind of reductio Adams for his natural philosophy, for his system. That is, his followers couldn't believe that he had died and thought it could only have happened because of some external intervention. Whereas others said, look, how smart could he really have been? He died at 54. When Descartes had talked in various places, including to the Catholic natural philosopher, Kendall McDigbee, the Englishman, he said, I can't make us immortal, said Descartes, but maybe 500 years, 54 falls pretty short of that, right? So there's an immediate kind of strike against his medicine, even though it's certainly influential in his immediate aftermath. And in fact, it's Cartesian physicians who really champion his philosophy into the universities. They're the ones who press it in. It's not the metaphysicians or the theologians, it's the Cartesian physicians. If you jump not even to the 19th century, when some of Descartes manuscripts related to medicine are rediscovered and published, but to today, my sense is that in fact Descartes, it's less the real Descartes that matters, as tends to happen with any figure over a long period of time. It's a kind of mythical figure. And in medicine, Descartes is often brought up to reclaim what the historian of medicine, Anne Harrington, calls this kind of fantasy of a pre modern time where we weren't fixated on just the body and we cared for the whole person and so on. So that myth of Descartes is quite present. Think about the funding that you get at hospitals or in research. There's the mental stuff in psychiatry that doesn't get anywhere near as much as the body stuff. That division is attributed, often even still in the literature, to Descartes. At the same time, though, and again, imagine something like neuroscience work, like Damasios, Descartes, Serra, right. Descartes is presented. It's not the real Descartes that's in that book. It's a version of Descartes and his dualism that's used to prop up a different approach today. If we really look at Descartes, and this is something that I think has come out in the conversation a little bit, he's not just interested in the body on the one hand, totally distinct from the mind. If you approach him from those branches and from medicine, you see a Descartes who sees the soul or mind really functioning and behaving in many respects with and through the body. And that's a different picture than the one we so often find in medicine today when it refers to Descartes. In some ways he's a really holistic thinker about health and medical care and provides a better model today than the mythical one that's so often appealed to.
- [33:18]
A
Okay, great. Speaking of holism, we are going to be going on to look at the whole of 17th century philosophy and beyond, not just Descartes and in general not just the famous people. I think next time we're going to be talking about skepticism in the 17th century, although it's hard to be sure. For now though, I'll thank Gideon Manning very much for coming on.
- [33:37]
B
Thanks very much, Peter.
- [33:39]
A
And please join me as we continue to move on through the 17th century here on the history of philosophy without any gaps.