 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 I'll be doing an interview with Professor James Wilberding of the University of Bochum. Hi James. Hello. And today we're going to be talking about nature in Neoplatonism and especially in Plotinus and his student Porphyry. Maybe you could start by just talking a little bit about the issue in general, because people have a tendency to think of the Neoplatonists as being not very interested in natural philosophy. Why do they think that and to what extent is that true? Well maybe we should start by defining what natural philosophy actually is. And there's a lot to it, but I think we can capture the nature of natural philosophy just by saying something like it's the science of explaining motion and change in the sensible world. So that's going to encompass all sorts of things like celestial motions, elemental motions and elemental change, biological motions and changes including embryology. So this is something that you can see Aristotle doing, you can see Plato doing, and the Neoplatonists are interested in this too. But for them of course they have a special sort of approach to it, which is to explain these sensible motions and sensible changes as expressions of intelligible principles, so that these forms are actually at work in the sensible world. So you're right, it's generally said that the Neoplatonists aren't interested in this sort of thing. In fact in the big history of philosophy by Tzeller, this German academic, when you get to the section where he's describing Plotinus' natural philosophy, the subtitle is, Plotinus doesn't have a natural philosophy. I think at one point on the page it even says, Plotinus isn't interested in nature. Which is just... That would be one of the shorter sections in the book. Yeah, no, and it's outrageous really. But there's a reason people say this sort of thing, and that is unlike say Aristotle and Galen, who is also a Platonist, these were people who were doing empirical research, dissecting bodies, looking at the anatomy and drawing conclusions about that and bringing that into their philosophy. The Neoplatonists weren't doing any kind of comparable empirical research. And coupled with that is the fact that that's often pointed to, the Neoplatonists were often very focused on texts and on their textual tradition. So they're reading Plato, they're reading Aristotle, and by that I don't mean to suggest that they're just doing interpretation, because they were very concerned to show that Plato and to some extent Aristotle, what they were saying is true. And that often caused them to take these texts as springboards, one might say, to do their own philosophy, but under the rubric of interpreting a text. So there's all sorts of new developments that they get into. And that could also lead one to think, well, they're just sort of armchair philosophers who aren't interested in the sensible world at all. And in addition to that, one might say, even though they're interested in texts, and even though Aristotle wrote all of these biological texts, the Neoplatonists don't really spend much time on these biological texts. There's no commentary on his biological treatises. And that's going to be another thing that drives people to this conclusion. But I would be quick to point out, I think, that Plotinus and the Neoplatonists are very interested in the sensible world. And you can see that, for example, in how they developed Plato's theory of forms. Right. So let's turn to Plotinus, who's usually credited with being the founder of Neoplatonism. What does he think about, first of all, the natural world as a whole? I mean, how is it set up according to him? Right. So in many ways, it's very similar to Aristotle's. So you have an everlasting universe, which is a sphere with the Earth at its center. But it's very different from Aristotle's in several ways. So for one, obviously, Plotinus, as a Platonist, is following Plato and thinking of the sensible world as a living thing, as a composite of body and soul. And that's something that Aristotle never really says. Moreover, although Aristotle and Plotinus both think that the universe is everlasting, they have very different approaches to arguing for this conclusion. So Aristotle says, he argues from the nature of the constitution of the heavens. And he says there's this fifth body that doesn't have any contrary properties. And destruction is always caused by a contrary property. Therefore, this fifth body of the heavens is never going to be destroyed. Is the so-called ether, right? Yeah, this is the ether. And so that's going to be one argument for the everlastingness of the heavens and thus of the universe. And the other would be, say, arguing that motion can have no beginning and no end. So if there's motion at all, which there obviously is, then the universe must be everlasting. So those are Aristotle's arguments. But Plotinus has a different approach. He has these hypostases, which I'm guessing you covered in a previous podcast. Right, and several previous episodes, actually. OK, great. So you have this metaphysics of precession and reversion, starting from these principles, which, and it's difficult to talk about this, but we might say these principles always have existed and always will exist. It's a bit more difficult than that, as you've probably mentioned. But the idea is that the sensible cosmos is just a necessary product of these higher principles. So the sensible cosmos always has to exist. So that's it. Plotinus' standard argument for the everlastingness of the heavens. Just to make sure we get that point across, so the idea is that the physical cosmos necessarily flows forth from these higher principles the way light does from a light source or water from a fountain. So you can't have them without a physical cosmos. So it's basically nothing about the cosmos in its own right that would keep it in existence. It's the fact that it's caused by something that's always exercising causality. I think that's right. And that's maybe distinct from some of the things that happens with the hypostases, because if we say, well, the soul is a necessary emanation of the intellect, that's not quite right, because there's this moment of reversion where the soul is in some sense creating itself. But you don't really get that with the sensible cosmos. But that depends on how one thinks of nature and nature's relation to the sensible cosmos, which I guess we'll probably have time to get to eventually, I would think. But before we get to what he thinks about nature as a principle, I know that he wrote a treatise actually on this question about whether the cosmos is eternal, and you've written a translation and commentary on this treatise. So you would be the ideal person to tell us about it. So tell us about it. Perhaps, yeah. We'll see. Right, so like I said, Plotinus has these arguments that he provides in all sorts of treatises, so throughout his career for the everlastingness of the heavens. But to his credit, he kind of puzzles over this question of whether the sensible universe is always numerically identical. So whether it's the same sensible universe or whether it's more like Theseus' ship, that parts are being replaced and ultimately maybe we have a different sensible universe. And it's interesting that he puzzles over this question, because you could think he's already committed to this idea that the sensible universe is a composite of body and soul. So this question about the deochronic identities, the identity through time with the sensible universe, is very similar to our concerns about personal identity through time. And often people just are willing to say, well, the soul is identical through time, and that suffices. So why isn't Plotinus worried about them? Why isn't Plotinus satisfied by just saying that the soul is identical through time? The idea then would be that someone might worry, well, why am I the same person now as I was when I was five years old, because there's none of the same stuff in my body? Exactly. And then you might expect Plotinus to say, Plotinus of all people, should be the guy to say, well, you have the same soul, so who cares if your body has changed? And you're saying that that's not his answer, at least in the case of the cosmos. That's right, yeah. So he acknowledges that there's this fundamental thing about the sensible world, which is that everything's in flux. And just as in the case of you and me, we're losing parts, we consume food to regain these parts, but what we see is there isn't quite the harmony that we need to live forever, for the body and the soul to be joined forever. So Plotinus's concern seems to be that any time there's flux, that shows that the body and the soul aren't really having the kind of harmony that can last forever. So for him, it's not sufficient to just appeal to the soul, because as long as there's flux, he's concerned that maybe the body and soul will come apart, in which case maybe we would have cycles of a universe, something like the Stoics, perhaps, that it's there, and then it ceases, and then it starts again. And in fact, that is what happens to humans, right? So they lose a body, then their soul goes into a new body later on. Exactly. So we have this reincarnation or transmigration theory. Why doesn't that happen to the cosmos, then? Yeah, well, he argues that, similar to Aristotle, that the heavens are the thing that aren't subject to flux. And he's a bit of two minds about Aristotle's solution, because Aristotle, as he sees it, just posited this fifth body that solved all of these problems. And he didn't really think that that was well supported. And this is interesting, because this is also the constitution of the heavens question, it's one of the questions where Plato and Aristotle seriously disagree. Aristotle says the fifth body, Plato says it's mostly fire, but all four elements are there. And so this is an interesting sort of test to see how Neoplatonists deal with this sort of question, because generally, they like to bring them together. But in this particular case, Plotinus, for example, says, well, Aristotle isn't justified, I'm going to follow Plato. And indeed, one might say he has good reasons for doing so, because Aristotle maybe hasn't really proven that there's this fifth body. Okay, but that still seems like it doesn't answer the question, because now if he said that the heavens don't consist of a fifth element, which is indestructible, but rather of the four sublunary elements, it seems like the heavens, too, should be destroyed, just like our bodies are destroyed. Right. So the easy answer is off the table, namely Aristotle's. So he sticks to Plato's idea that all four elements are there. But again, he uses this as an opportunity to really investigate the constitution of the heavens. And he pushes Plato's answer in Aristotle's direction, and he ends up saying, well, yeah, it's mostly fire, but there's a very different kind of fire in the heavens. And this fire is almost immaterial, which means it's going to allow itself to create a kind of, to engage in a kind of harmonious relationship with soul, such that there won't be any flux, which is actually, he's in a good position, he's on good footing anyway, because it doesn't look like there's flux from the heavens, unlike in the sensible world. So really, he's just trying to support that through some kind of theory of the material of the heavens. It's almost like he thinks the heavens are some kind of intermediary or compromise between intelligible things and physical things, right? They're permanence and almost immaterial, but they're physical and are visible, for example, the way that sublunary bodies are. Yeah, that's right. And I think that's actually maybe more true than a lot of people want to admit. I mean, what we saw, for instance, in Aristotle is you have this sensible world, and then you have these heavens, which are always moving and in some sense, you know, divine. And then beyond that, beyond the heavens, you get this unmoved mover. And it's the same with Plotinus, actually. You have the sensible world, which is subject to flux, and then you have the heavens, which are divine in some sense. And just beyond that, you seem to get something like the intellect. Okay, so he has a good kind of physical story, we might say, about why the world is everlasting. On the other hand, he does have this world soul, and yet he also invokes nature as a principle. And in fact, he wrote a whole treatise about nature. What's then the relationship between the world soul and nature? Right. So the world soul is distinct from the hypostasis soul, insofar as the hypostasis soul is completely in the intelligible world, we might say. But the world soul is engaged in the sensible world. And what Plotinus does is basically say, well, the world soul, similar to, say, human souls, consists of two parts, we might say. And there's going to be the part that is actively at work in the sensible world and in matter, and that's nature, the lower part. But he also reserves an upper part of the world soul that remains in the intelligible world. So in some sense, nature is just the lower part of the world soul. It's almost like another bridging principle then from the intelligible to the physical realm, right? Because it has a foot in both realms, as it were. That's right, yeah. That's interesting. So what kinds of things does he use nature to explain as opposed to the world soul? I mean, that's a question. To what extent the world soul is responsible for explaining anything directly and not by means of nature. It seems that nature is the one that's really doing the work in the natural world. And I think it's pretty much explaining almost everything, one might say. I mean, again, I mentioned at the start that there's this interesting biological development in the theory of forms. So for example, well, it's actually not even clear in Plato whether there's a form of human being. Young Socrates in the Parmenides seems to have his doubts. Maybe in the Timaeus there is one. But even in the Timaeus, Plato describes how these generated gods construct the human body. And it's not clear that they're doing this because they have knowledge of the form of human being, for example. They just seem to be troubleshooting and trying to come up with a good plan for a human being. In Plotinus, the theory of forms takes a decidedly biological turn. So there are forms for all sorts of living things, humans, dogs, oxen, presumably even snakes, even plants there are forms of. And what happens with these forms is as they're handed down, so they start in intellect, they're handed down to soul. And ultimately they're handed down to nature, which is at work in the sensible world. And at each time they're handed down, they become more pluralized and more particularized, such that by the time you get to the level of nature, you don't have the form of human being. You have a whole variety of forms corresponding to all. So for example, in the case of a human being, all of the parts of the human body. And these are going to be the things that actually do the work in the sensible world and create the human body. And it's almost like all the humans who ever exist are kind of unfolding of the possible content of the form of man or something. That's right. Yeah. So at one point, Plotinus investigates this idea of whether there are forms of individuals. And this is of course a very controversial question that he engages with. But I think the soundest reading of his response to that question is to say, at the level of nature, there is this form of Socrates, say, insofar as at the level of nature, you're going to have a principle of his snub nose and his bulging eyes and all of these other features. But then all of these together, even if we count all of these principles together as the form of Socrates, this is just one possibility within the form of human being. So the idea is, well, how many human beings would it take to instantiate the form of human beings? His answer seems to be a lot. Loads. Yeah, loads. So as many as fit into the great year, is what he says. The great year being how long it takes for all the heavenly bodies to realign to their starting position. Right. Exactly. Okay. I guess one thing that's become very clear from all this then is that the Neoplatonist, or at least Plotinus, he is interested in the physical world, but he always approaches these questions about natural philosophy with the principles of his general philosophy in mind. For example, the idea that there are intermediaries between higher things and lower things and that you have a kind of gradual emanation of multiplicity from a more unified set of principles. I want to turn now to his student Porphyry and talk about one other text, which again you've worked on. And this is a text about embryology, in other words, the nature and generation of the human fetus. And I guess this is a rather surprising thing to find a Neoplatonist working on. Can you tell us a little bit about the prehistory of this and maybe why he would have been interested in it? Right. So I don't actually think it's a very surprising thing for a Neoplatonist to be interested in. The embryology was always a top-off in ancient philosophy, and you can find the very earliest philosophers working on it and the very latest philosophers working on it. I suppose one of the issues, which is, I mean, there were a number of issues that were central, but one that maybe we could focus on is whether just the man provides a seed for the embryo, or whether both parents are, so whether there's a female seed. And there are lots of arguments on both sides, but maybe one of the strongest arguments on each side would be for the two-seed theory. If you have two seeds, you can easily explain why the offspring sometimes resembles the mother, because you have these formal principles provided by the seed. The problem with the two-seed theory, though, is if you say that the mother has a seed, then the man seems superfluous. And that, among other things, is what led Aristotle to say that there's in fact only one seed. And it's interesting, because if one follows this early tradition, one can find medical philosophers and physicians always sort of asserting the two-seed theory. So Hippocrates and Galen are both on the two-seed side. But Aristotle is a strong proponent of the one-seed theory, and all of the Neoplatonists just follow Aristotle. When you say that the man would be superfluous, do you mean the woman could literally get pregnant just by herself, or do you mean that the man wouldn't do anything to explain the presence of a human being? I think I meant, in some sense, the former. Of course, all that really means is that more explanation is needed as to why this female seed is not sufficient to create an offspring all by itself. So what happens then is, even with the two-seed theorists, say Galen, you get this female seed, but it's still inferior in some sense to the male seed, because it can't be self-sufficient. And Porphyry goes for the one-seed theory. Right. And this is interesting, and this maybe goes back to this question that we started with as to why people don't view Neoplatonists as actually being interested in the empirical tradition, because not only does Porphyry follow Aristotle's one-seed theory, he doesn't even really think of this as a problem. He doesn't even investigate the two-seed theory, unlike, say, Aristotle, who argues extensively for the one-seed theory, and unlike Galen, who argues extensively against Aristotle. Porphyry just assumes it as if it were obvious. And he doesn't really seem to engage with any texts of Galen, and he does sort of cite some Hippocrates, but not much. That's interesting. So these are very obvious things for him to have been looking at if he's thinking about embryology. Right. And he just goes straight back to Aristotle the whole time? Yeah, although he's not really focusing on texts of Aristotle either. Like I said, it's not clear that they had access to all of the biological texts of Aristotle. But he does sort of take the starting point of the one-seed theory, and thus he's confronted with this problem of explaining maternal resemblance, which all one-seed theorists are. So what does he think the woman contributes to the process of forming the embryo then? Yeah, exactly. So he needs to account for maternal resemblance in some other way, and he has an ingenious way of explaining this. So basically, he sees embryology as, as I would put it, a kind of empirical instantiation of precession and reversion. So the emission of the seed is a form of precession, in that the father is creating an image of himself, and through these form principles that are contained in the seed. But as we see with reversion, something needs to, it needs to somehow come back to its source. And it can't go back to the male, because the male is no longer in the picture. So it has to basically revert to the female. So what Porphyry says is that there's no female seed, but the seed reverts and, as it were, is actualized by the mother's soul. And this is what's going to account for the maternal resemblance. And what's interesting here is he has another piece of evidence on his side, which we wouldn't really perhaps today regard as a piece of evidence, but there's this phenomenon that's often called idioplasty. Have you heard of this? It's funny from you. Right. And so a famous, so basically the phenomenon of idioplasty is this, and this was, I should emphasize at the start, this was widely agreed to obtain in antiquity, and even way past antiquity. And maybe we should also reassure listeners that this is not true, so the prospect that you're about to hold out. Right, so don't try this at home, basically. But the view was that whatever the mother, and curiously it's only just the mother, whatever the mother is looking at, and in some cases thinking of, at the moment of conception, this will have a very visible impact on the appearance of the offspring. So Seranus gives a very unfortunate example of a mother who looked at a monkey while having intercourse and ended up with a monkey-like offspring. Oh dear. Yes. So this is, as I said, it's a phenomenon which is a very real explanations in ancient embryology. And Porphyry seems uniquely positioned to explain it. And his explanation is, well, this just shows not only that the mother is influencing the form, the appearance of the offspring, but that she's not doing it through seed. She has to be doing it through her soul. Right. Actually, you could almost say that he's got a more feminist take on embryology than Aristotle because he actually has the woman doing quite a lot, doesn't he? Exactly. In fact, he twice refers to the female as the demiurge of the offspring, where Aristotle had reserved that term exclusively for the male. And does he have in mind the divine craftsman of the Timaeus there, who's called the demiurge? Or does he just mean that it has some kind of making function? Demiurge means craftsman, right? Exactly. So demiurge means craftsman. I'm not sure he's explicitly trying to make a link to the Timaeus, but I think anytime you use that word, anytime a Neoplatonist used that word, of course he's aware that the demiurge is in the picture. And speaking of explicitly making links, I'll now encourage you to listen again next time when I will be looking at Porphyry more generally. But for now, I'd like to thank James very much for coming on the podcast. Thank you for having me, Peter.