Is the universe eternal? With Professor Peter Adamson

Hello everyone. Hello and welcome to Blogging Theology again. Today, I'm delighted to talk again to Dr. Peter Adamson. You're most welcome, sir.

Hi, nice to be back. Good to see you. Peter appeared on Blogging Theology five months ago when he discussed the question, "What is Islamic philosophy?" It proved to be a very popular video, gaining over 31,000 views, and I'll put a link to it in the description below.

Peter is the host of the hugely popular History of Philosophy podcast, which appears as a book series with Oxford University Press, and I'll put a link to that as well. He teaches at the Ludwig Maximilian University of Munich, where he is Professor of Late Ancient and Arabic Philosophy. Peter's research has mostly concerned philosophy in the Islamic world and its Greek sources, and he has published and edited numerous books and written dozens of research articles in this area. He says his hobbies include writing podcasts, watching Buster Keaton movies, and writing more podcasts, as you do.

Today, Peter has kindly agreed to introduce us to a fascinating topic in Greek and Islamic philosophy: Is the world eternal? In his book, The Incoherence of the Philosophers, the famous Muslim theologian and philosopher Al-Ghazali attacks Ibn Sina's theories about the eternity of the universe. So, would you like to introduce us to the historical background and the philosophical issues, Peter?

Sure. So, let's just first of all clarify what we're talking about here. So, we're talking about the eternity of the universe. There are a couple of problems already here terminologically. We have the words "eternity" and "universe," so we need to think about what those two things mean. Neither of them is too puzzling, but it's still worth saying at the beginning.

Eternity in medieval philosophy is an ambiguous word because sometimes it means timelessly eternal. God is often thought to be timeless. This may come up again, actually, when we're talking about how the debate unfolds. So, something that's timelessly eternal, at a minimum, is something that's not changing ever, and it might be somehow beyond time. Like, maybe, for example, tensed language like past, present, and future verbs, verb tenses wouldn't apply to it. Not exactly clear how to think about this, but in a way, we can set all that aside because when we ask whether the universe is eternal, all we mean is, has it already existed forever?

There's a further issue about whether it will exist forever into the future, and although that's an interesting question, it's not really what they're debating in this context. What they're asking about is whether the universe has already existed forever, and by forever, I mean for an infinitely long time. Another way of putting this is that the universe doesn't have a beginning. So, it doesn't have a first moment in time. Right? So, that's the question as far as eternity goes.

The question as far as the universe goes is, you might think, well, anything other than God would be the universe. So, for example, it could be that the universe was radically different, like everything was made of cheese at some point or something, but that would still count as an eternal universe if this cheese universe had turned into our universe. But actually, what they're usually thinking in this context is that the universe has always existed pretty much in the way that it does now.

And in a medieval context, they're thinking about the Aristotelian universe, which means it's a sphere. The outside of the sphere is the so-called sphere of fixed stars. So, these are the stars that move together every night as you see them apparently moving over the earth. The earth in the middle, and in between, there are concentrically arranged further spheres on which are seated the planets. But actually, most of what's up there is not the visible planets and the stars. It's these sort of crystalline, perfect, indestructible spheres, which are see-through, so they're transparent. You can't actually see them. The only reason you can see them is because there are these visible stars heated upon them, and those move.

So, I sometimes compare this to looking at it's like your city. You're sitting inside a bunch of nested goldfish bowls, and on in each goldfish bowl, there's a gem situated which is rotating along with the goldfish bowl around the earth. Okay. And we could get more into the cosmology, but actually, that's not going to matter very much for the debate. It's going to matter a little, I think, as we move along and look at the arguments.

So, the question then, to sum up, is whether this spherical universe has always existed or whether it came into existence for the first moment in time. Maybe one other thing that's worth mentioning about the cosmology before we move on is the question of what's outside the external, outer, so-called outermost sphere with the fixed stars on it. And the answer is nothing. And when I say nothing, I don't mean empty space or void vacuum. So, we're not talking about don't think about outer space. I mean nothing, not even empty space.

Conceptually, what does nothing mean? Is it nothing a thing, or is it evidence of things? It's ambiguous. I don't want to go down that rabbit hole, but yeah, it is not an obvious concept philosophically. What do we mean by nothing? But, but, um, I don't, I say I don't want to pursue that line of thought, but just flag it as an issue. But I mean, really, all we need to bear in mind is that for an Aristotelian, there's no empty space outside the universe. So, the limits of reality are the edge of the cosmic spheres.

And one thing that was pointed out by Al-Ghazali, actually, in the debate is that this means that for an Aristotelian, there's a disjunction between time and space because time for them goes on and on and on back into the past. Right? So, there's no limit to time in the past. There's a limit to time, sort of going forward, which is the present moment, and we're keeping that, we're pushing the limit on as we keep moving towards the future. But there's no limit in the past, right? Because the universe has always existed. Whereas there is a limit in space, right? So, there's an edge to everything, which is the outermost sphere. Interesting.

Okay, so now, if we move on to the actual debate as it unfolded in antiquity, I think actually, an interesting fact about the antique debate is that the main driving force behind it is something that's not actually that important in medieval philosophy, although it does come up. And this is really an issue about exegesis and philosophical authority. So, by late antiquity, once Neoplatonism kind of comes to be the dominant way of doing philosophy, and we don't need to get into that except to say that like after Plato and Aristotle, there's a period where we have these various schools of philosophy that become dominant, especially Stoicism, but also Epicureanism and Skepticism. We call that Hellenistic philosophy. Then in late antiquity, Plato and Aristotle sort of edged them out as being the main sources.

And the philosophers of late antiquity have a problem whenever Plato and Aristotle seem to disagree about something. So, for example, Aristotle criticizes Plato's theory of forms very heavily. And so the Neoplatonists, who would like to use both Aristotle and Plato as authoritative sources, they have a problem. They have to figure out what to do about this. And they might say things like, "Oh, well, when Aristotle criticizes the theory of forms, what he's doing there is not criticizing the theory, but certain ways of understanding the theory." But there's some other way of understanding the theory according to which it's correct, which is a completely bogus reading of Aristotle, but it's the kind of thing they would say.

And one of the main points of tension or apparent points of tension between Plato and Aristotle is our question whether the universe is eternal. Right? Because in a dialogue which people don't read that much anymore in, like, universities, but which was absolutely one of the most important dialogues in late antiquity and the Middle Ages, and the Middle Ages, certainly the most important dialogue for Plato in terms of its influence, this is called the Timaeus. And it's an account of a divine craftsman called a demiurge in Greek. Long time to learn to pronounce that word, but it's demiurge.

Yeah, well, I mean, it's a demiourgos in Greek. You can do whatever you want with it. I usually say demiurge in English. Yeah, yeah. So, the demiurge is a god that creates the physical cosmos. Yes. Not to be identified with the god understood in the Western, not the god of Islam, we go to Christianity, go to Judaism. This is some other kind of configuration of the deity. It's not identified simply with our understanding of God. That's right, for sure. Although one reason why the Timaeus is so popular in the Middle Ages is that it seems to be one of the pagan philosophical works that comes closest to affirming the creationist, you know, religious assumptions. Yeah. So, at least you've got this creator God. Right? Yeah.

But one thing that it looks like may be different between the Timaeus God and the Abrahamic God is that this God seems to be creating the universe out of some pre-existing stuff. Again, very difficult to interpret whatever, what Plato's talking about there. But Aristotle implies that Plato was just talking about creating the universe from pre-existing matter. So, you have some unformed matter, and then the demiurge comes along and imposes form on it. Notice, by the way, that takes us back to the question of what do we mean by talking about the universe? Yes, because according to that story, so as a kind of like superficial, at least, reading of the Timaeus might give you the idea that there's some unformed matter which is eternal and it's just kind of sitting there waiting for the demiurge to do something with it, and then the demiurge comes along and makes it into a universe. You might also think the fact that he's called a craftsman, because that's that Greek word, implies something like a carpenter. Right? So, the idea of making it out of making the universe out of pre-existing matter, the way a carpenter would make a table out of wood, is kind of, yeah.

In any case, there's a passage in the Timaeus where Plato explicitly raises the question, or has his main character, Timaeus, explicitly raise the question, whether the universe has a beginning or not. So, he says, "Is it, does it have a beginning, or did it come to be?" And the Greek words here are important. So, he says, "Does it have a beginning?" An arche. Okay. Yes, which is a word that lives on in English in words like architect. That's the chief architect. Yes. Um, so, techne is craft, and arche is chief or beginning or principle. Yes. And then when he says, "Has it come to be?" he uses the word gegonen. So, that just means "has come to be." Yeah. You'll see in a second why I'm sort of dwelling on the Greek words.

So, so it looks like, and then Timaeus in the dialogue says, "It has come to be." So, it looks like he's explicitly affirming that the universe came to be with the first moment in time. Which would be okay, except that Aristotle is even more explicit that the universe is eternal. Yes. And he even uses the eternal motions of the heavens in his proof for God's existence. So, again, that's kind of a long story, but the basic idea is that it's impossible that a body be the generating power that gives rise to an infinite motion. So, if the heavens have already been moving infinitely for an eternal period of time, that must mean that they have an incorporeal cause, and that would be God. Right?

So, on the face of it, looks like you've got this clash between Plato on the one hand, Aristotle on the other. Plato thinks the universe is not eternal. Aristotle thinks it is. And these are our two main authorities. So, we don't really want them to disagree. So, that's like a central problem that drives the eternity debate in antiquity. Gosh.

Yeah, so moving on to, um, the Islamic philosophers. Ibn Sina, of course, he's known in the West as Avicenna, if I pronounce that correctly. But his Arabic name is Ibn Sina, and he was the author of a numerous work, a hugely influential philosopher, and controversial for many people. And this is the work, The Metaphysics of Healing, which is perhaps relevant to your discussion. But Al-Ghazali, in his volume, The Incoherence of the Philosophers, offers a sustained, relentless, and ruthless critique of Ibn Sina's views. Which I'll, obviously, invite you perhaps to elucidate. What is the argument about why is Al-Ghazali so critical of Ibn Sina and so on? And then I have a question about this whole issue, um, toward later on, perhaps.

Right. Okay. So, actually, let's first fill in just a bit of the story between where we just left Plato and Aristotle and these guys, because the arguments against the eternity of the world that are circulating in the Islamic world actually stem to some extent from the late ancient context. So, what happens there is that most of the Neoplatonists want to say that the universe is eternal. So, even though they're playing this, they agree with Aristotle. Right? So, they need to offer a reading of Plato according to which he also thinks the universe is eternal. And this is actually why I mentioned the Greek words.

So, when, so there's a Plato, a Neoplatonist named Proclus, who says, well, when the Timaeus says that the universe has an arche, it doesn't mean that the universe has a temporal beginning. It means that it has a principle or a cause, like a first principle, because, as I said, arche can mean that too. And when it says that the universe has come to be, gegonen, what it means is that the universe is in kind of flux, is changing all the time, as opposed to the divine source, which is unchanging.

And then a late ancient Neoplatonist, who was also a Christian, named John Philoponus, attacked this reading of the Timaeus. Said, no, no, the Timaeus is to be taken kind of literally, or at its, you know, at the first blush reading, saying that the universe does begin. And furthermore, there are all kinds of arguments we can give to show that the universe had must have had a first moment in time. And he has arguments to show that the idea of past eternity is impossible. And we can maybe get into that. But anyway, his arguments against the eternity of the universe are then transmitted into Arabic, and they were already known before Ibn Sina and Al-Ghazali.

So, actually, when Al-Ghazali is attacking Ibn Sina, he's able to draw on some of the same kinds of arguments that have been given against the eternity of the universe already in antiquity by Philoponus, and then by some Arabic-speaking philosophers before Ibn Sina. And in fact, I mean, people often suggest that that a kind of definitive feature of philosophy in the Islamic world is that all the philosophers believe that the universe is eternal and all the theologians think it isn't. So, we have this kind of paradigmatic debate between Ibn Sina and Al-Ghazali. But they kind of extrapolate from that to think, well, all of the philosophers think the universe is eternal, all the theologians think it's not eternal. That's not true.

And others who thought the universe was at a beginning in time, that it wasn't eternal? Well, actually, no. Al-Farabi does, does seem to, I mean, there's a little bit of unclarity about this, but it seems that Al-Farabi thought the universe was eternal, and Ibn Sina did, and Averroes also. Known as the Philosopher. Yeah, yeah. These are the three most famous Aristotelians in the universe in the Islamic world. Islamic world, not to be confused with the universe. So, because they're famous, there's a kind of easy assumption which is that all of the so-called philosophers, all of this is what we talked about last time, right? So, there's this contrast between Kalam, if you have these Greek-inspired philosophers, and these Quran-inspired theologians. And people who assume that all of the philosophers, the philosophers are adherents of the eternity of the universe. But actually, that's not true.

The first philosopher who's making significant use of Greek works is Al-Kindi. He argues explicitly against the eternity of the universe using arguments from Philoponus. A Jewish philosopher at the same time as Ibn Da'ud does exactly the same thing. Around the same time, you have Abu Bakr al-Razi, who's not an Aristotelian or a Platonist, but he's a Platonist in a way, and he's very influenced by Galen. Because he's a doctor, he also rejects the eternity of the universe. And you can kind of go on from there and talk about other philosophers like Miskawayh, who's a contemporary of Ibn Sina. So, actually, I don't think that it's true that even among the philosophers there was a kind of orthodoxy about this.

You say, I mean, in his book, The Incoherence of the Philosophers, which we'll come to in a second, appears to suggest that Greek philosophers did believe in the eternity. He seems to have this generalized view that Greek philosophers did believe in the eternity of the universe. And you're saying, actually, that's wrong. With Al-Ghazali, basically, as a matter of fact, just got it wrong. In fact, there were some prominent ones who did, but most didn't. Yeah. And in fact, I mean, when he uses the word "philosopher" or the word "philosophy," father, actually, I mean, that's a little bit misleading because what he really means is just Ibn Sina. So, he says, "The philosophers say," and then he, oh, what he's always doing there is either giving a view of Ibn Sina's or an argument that you could give on behalf of Ibn Sina. But he's often saying, "The thing is, some philosophers would have strongly disagreed." In particular, like Al-Kindi would have strongly disagreed that the universe... So, so actually, this is a, um, kind of symptom of something you mentioned before, which is just the powerful influence of Ibn Sina. So, once he comes along, he kind of pushes everyone else out and makes it hard to see that there's a difference between being a philosopher and being an Avicennan, a follower of Ibn Sina. That but actually, it's, I mean, it's a historical matter, it's important to distinguish those two things. Right?

But in any case, that, I mean, for us, I guess, in this conversation, the more important issue is, given that it wasn't kind of automatic that Ibn Sina would have would endorse the eternity of the universe, why did he? That's a good point. Yes. And one obvious answer, which might apply to Al-Farabi and Averroes, would be, well, they know that Aristotle believed in the eternity of the universe, and they are Aristotelians, like, they're more committed to Aristotle's authority than maybe some of the other Arabic-speaking philosophers were. And so they kind of feel like they have to go along with him on this. But actually, I don't think that's a very good explanation in the case of Ibn Sina. It would be a good explanation in the case of Averroes, because he's like a died-in-the-wool, hardcore. But in Ibn Sina, he's like, very proud of the fact that he always reconsiders every issue, thinks about whether he agrees with Aristotle. He's often critical of Aristotle. He's not usually rude about Aristotle, but he definitely disagrees with him on a number of points. And if he hadn't been philosophically convinced that the universe is eternal, he wouldn't have said it was just to go along with Aristotle. I think that's clear. Yeah. Yeah.

So, to understand why he thinks the universe is eternal, we need to say something about his views on God. And I think we might have touched on this in the previous conversation, but just as a quick reminder, he proves that God exists by showing that there's a necessary existence. Oh, God, right? So, the idea is, everything we see is contingent. It can't, it can't be that contingent things come to be without having a necessary cause. So, there's this necessary cause. There's only one such necessary cause, that's God. That's how he kind of gets his philosophical theology going. And when he says that God is necessary, he wants to say not just that God necessarily exists, which everyone would agree with in this culture, right? So, God doesn't just happen to exist. Right? God has to exist. Yeah. Um, it, but furthermore, Ibn Sina wants to say that everything about God is necessary.

So, here's a reason why you might think that if you're Ibn Sina, or a reason why he did think this. Suppose that there's something about God that's not necessary. So, for example, suppose that he may create the universe, but may not. Like, it's sort of up to him to decide. Or indeed, suppose that the universe isn't eternal. Said that for a while, he wasn't creating the universe, and then suddenly he is. Hmm. Right? So, like, on Tuesday, he's not creating the universe, but on Wednesday, he is. So, that would mean that there's something contingent about God. There's something about God that may or may not be the case, and it turns out not to be the case at first, and then to be the case later. He's first, he's not a creator, then he is a creator. So, now, Ibn Sina would say, "Well, let's explain why this happens." It can't be due to God himself or God's nature or essence, because if it were due to God's nature, then of course it would follow automatically from his nature. So, it would always be true of him, and it would necessarily be true of him. Right? Because, so, if you imagine that God creates the universe essentially or necessarily from his nature, that would be like water being wet. Right? So, water can't not be wet. It's always wet. Similarly, if God's essentially guaranteed to create the universe, then he would always be creating it.

Of course, this is the implication that God has no freedom, no free will, so to speak. He's compelled. He's a necessity. He's necessitated to act. That's exactly. You're kind of skipping ahead to his objection there. Yes. That's but that's you're right, that's exactly because always worry.

So, and, and I mean, Al-Ghazali would say is well, God does it by free will. But what did Ibn Sina would say is well, look, either God generates the universe through himself, in which case he'd have to do it essentially, the way that water is wet, or there would have to be some other factor involved. Some other cause would come along and make God create the universe. Like, for example, that makes it sound very much a matter of compulsion, but it could also be something like circumstances change, and it becomes better for the universe to exist than not to exist. Right? But whatever it is that happens that makes God generate the universe, it would be some kind of cause that's being exerted on God, and then God would have a cause, which we rule out.

So, what you just said is exactly Al-Ghazali's response to that. But before we maybe get into that and talk about the response, I think it's worth kind of dwelling on the internal logic of what Ibn Sina is saying. So, Ibn Sina, what Ibn Sina is saying is, God is necessary, and what that means is that everything about God is necessary, not just that God exists, and that he's powerful and knowing and good and all the things that we want to ascribe to God, but God cannot take actions that are non-necessary. Right? Because if he did, then there'd have to be some causal influence being brought to bear on him, which explains why he's doing it. Because he might not have done it, right? So, it's like it's contingent, right? Sometimes they compare this to, to a set of scales that need to be preponderated to do one thing rather than another. So, whatever it is that kind of comes along and puts its thumb on the scale to make God create, that would be a cause that's exerting some kind of influence over God, and that's what he wants to rule out. And actually, that's that's very, very intuitive, right? Yes. And very logical. I mean, I, I would, I raise this question later on, but I do want to just observe here that both of these individuals, Ibn Sina and Al-Ghazali, are self-identified as Muslims. And this is, they're not identified, I think, primarily as philosophers or but as Muslims. So, I just raise that point because it links into a question I'm going to ask about the Quran, basically, and what it says, which may or may not be referred to very much in these conversations, anyway. But anyway, I just wanted to point out we are talking about the interlocutors of both Muslims. They're not just secular Hellenistic philosophers. That's right.

And although, but you're right that Ibn Sina, when he gives this whole argument, he might like throw in a quotation from the Quran at the end and say something like, "Oh, that's why it says that God is powerful in the Quran." But, but the whole thing that what's generating it is a philosophical argument. Definitely.

Okay, so maybe now we can get to Al-Ghazali's response, which is very complicated, but at the core of it is definitely the idea you mentioned before. So, what Al-Ghazali wants to do is to say that God is capable of doing something contingent, and that is important to him because he wants God to have free will. And to him, free will means being able to choose between alternatives that are genuinely open. Actually, Ibn Sina has anticipated this objection. So, he says that, he says that God is free or is at least willing. But what he then does is he interprets that to mean that there's nothing external compelling God to act. So, he says, "Well, we can say that God is freely willing to generate the universe or emanate the universe because nothing's making him do it." So, he's free in the sense of being free from compulsion.

Al-Ghazali thinks that that's not good enough, and that freedom needs to mean literally choosing between genuinely open alternatives. And he says, "Well, actually, in a way, the Aristotelians should be committed to this too." Because let's consider again the size of the universe. So, the universe is however big it is, right? As we saw, it has these limits. There's nothing outside it. Well, surely it could be like one inch bigger or one inch smaller. So, it looks like God is making choices between genuine alternatives there, and he could have made it bigger, he could have made it smaller, but he chooses to make it that size.

Right? Actually, the book you showed us, The Incoherence of the Philosophers, yeah, there we go. That's a translation. Michael Mamura recommended by most people. It's a standard text. He's actually got the parallel Arabic and in English translation. It's very readable and contains all these arguments and relentless arguments that Al-Ghazali deploys in attacking Ibn Sina. But it doesn't seem to quote the Quran very much. We'll come back to this. And even mention Ibn Sina by name. I don't know if maybe I missed that, but I couldn't see Ibn Sina mentioned by name in the text. Yeah, he mentions him eventually when he accuses him of heresy, okay, being an apostate, actually, by upholding these doctrines.

But what I was going to mention is that in Averroes, the Aristotelian commentator I mentioned before, he wrote a work called The Incoherence of the Incoherence. Yes, yes. And in that, he says, "Oh, it's actually not true that the universe could be an inch bigger." Because the universe is like perfectly designed in this providential way, so that all the heavens move in exactly the right way. And if anything were even slightly different, everything would kind of go berserk. So, like, the heavenly influence on the lower world where we live would be disrupted if the universe was even slightly different.

Another nice argument that Al-Ghazali gives is, if the universe is going around like this, couldn't it also have gone around like this backwards? Or if the universe is like this, couldn't it be like that? Yes. And even Ibn Sina says these things are all meaningless because, like, up is just like wherever the North Pole is. So, if the North Pole were over here, that would be up. Right? So, you so you get these nice kind of space-time analogies that are raised. But I mean, what he's really after is, he he explicitly wants to say that God can choose between two genuinely open alternatives. That's this point. And in fact, he even gives a nice example which anticipates something we associate with Latin medieval philosophy, the so-called Buridan's ass case, where a donkey is between two bales of hay, yes, and has to choose between them.

So, his, so Al-Ghazali gives the example of, um, someone offers you two dates, like, not not a date like a date to go out to dinner in a movie, but, uh, yeah, with the little fruit, dried fruit, right? And he says, well, if someone offers you two dates and they look exactly the same, and you would like one, and he, and the person says, "You can only take one," then you wouldn't just kind of sit there looking at them forever. What was a good reason to take one rather than the other? You just pick one. And so, what, so Al-Ghazali brings us up because he thinks that one of the arguments against the eternity of the universe would be that there's no rational basis on which God could choose the first moment of the universe. And it's sort of again, the same kind of thought, like, well, there has to be some cause or reason that's bringing God to create now rather than earlier. Um, and, uh, it was always response to that as well. If you want to create a universe, you have to do it at a specific time. So, God just chooses a time, and that's rational, just as it would be rational to choose one of the two dates to eat. Wow. Very interesting.

What other arguments does, uh, Al-Ghazali deploy to refute the idea of the eternity of the universe?

Yeah, so some of the arguments involve infinity in interesting ways. Yes. So, and this had always been one of the biggest problems with the thesis of the eternity of the universe. This is a subject that is of great interest in in contemporary philosophy, you know, what is infinity? And different kinds of infinity. I know it sounds counter-intuitive, but when you actually hear the arguments, there are different kinds of infinity. Not all infinities are the same. And so it's become a fascinating discourse in contemporary, uh, uh, philosophy about the nature of that. But I've always found it a baffling concept, the other idea of infinity, but it is elusive, I think, to to many people.

So, I interrupted you. No, no, that you're right. I mean, that is, in fact, one of the things that I'm really fascinated by with the whole eternity debate is that it raises these, I mean, you might not care about the eternity of the universe, especially because, you know, modern physics, you might think, has already kind of given us the answer or something like the answer. So, why are we interested in this? I think actually the main reason it's interesting is that it bears on a whole bunch of other issues, like the nature of free will. So, for example, that question, is an agent free because nothing's compelling the agent to act, which has been seen as a view of freedom, or as an agent free because the agent is choosing between genuinely open possibilities, which is, was always view of freedom. That is something that philosophers still debate. And this is one of the earliest clear contrasts between those two conceptions of freedom. Or here, you have people thinking about, like, the nature of infinity and what kinds of infinity are possible and what kinds of infinity aren't possible. Yes.

So, what, and one of the problems with the, um, thesis that the universe is eternal had always been that it seems hard to believe that the universe has already existed for an infinite period of time, because one way of putting this would be, well, if the universe has already had existed eternally, then an infinite amount of time must already have elapsed. Yes. But you can't finish, yeah, anything, right? So, how did we get to the end of this infinity to get to the present moment? And what the Aristotelians would say is, well, that's kind of the wrong way of thinking about it. So, don't think about it as an infinite past that's already finished elapsing. Think of it more like, start from the present moment and go back. And now I'm willing to say, well, any number you you mention to me, I'm willing to say that the universe has already existed for that number of years. So, you say a billion years? I say, yes, it's already as a two or a billion years. A trillion years? Sure. 10 trillion? Sure. Right? And you just, you can go as high as you want. And so, the infinity involved is more like the infinity of the finite numbers, which is not absurd.

Mm-hmm. Um, but we really get started getting into more like technical and interesting issues about infinity with another argument that Al-Ghazali gives. And here, um, this is why I mentioned before the thing about the nested spheres. So, remember I said that there are some spheres that are closer to Earth that have planets on them? Yes. And then there's the outermost sphere with the fixed stars is going around once a day, right? And the Earth is staying still in the middle. That's the cosmology. So, these these planetary spheres are rotating at different speeds. So, let's just say for the sake of argument that, like, the sphere of Mars moves twice as fast as the sphere of Jupiter. Or, and what I mean by that is just that it goes, it it rotates around the earth twice every time Jupiter does it once. Yeah. Okay. Obviously, that's not the right math. Astronomers know that Mars doesn't go around you're twice as fast as Jupiter. But the point is that it's different. Their speeds of rotation around apparent rotation around the Earth are different.

So, now, Al-Ghazali says, "Okay, so let's say the universe has existed for an infinity of time." Well, that means that Mars has gone around the earth an infinite number of times, and so has Jupiter. But since Mars is moving twice as fast, or is rotating around us twice as often, the sphere of Mars has formed an infinite number of circuits around the Earth that's twice as large as the infinite number of circuits that Jupiter has performed. So, we've got twice infinity and once infinity. So, two infinities, one of which is double the other. And then, Al-Ghazali says, "That's absurd." Yes. Because infinity is infinity. You can't double infinity. Now, on modern mathematical intuitions, that's not the case anymore. Yeah. But you can see that, like, something's interesting is happening there where someone's like thinking about whether you can do things like multiplying infinity by a finite number, in this case, with two, right? So, that's pretty interesting.

Another argument he gives is that, um, the philosophers are trying to get out of the the commitment to what they think of as an actual infinity, like that thing about an actual infinity of time actually elapsing so we can get to the present moment. And they get around that by saying, well, don't think about it that way. Think about going backwards. Don't think about going forwards from an infinitely remote time. Think about going backwards to just ever higher finite numbers of elapsed years in the past. So, Al-Ghazali says, "Well, there's something else they're committed to which will land them with an actual infinite number of things that exist right now." Which is the immortality of the human soul. This is kind of from left field, right? Yes. He says, rightly, that the philosophers, I.E. Ibn Sina, are committed to the immortality of the soul. So, that means that every time someone dies, their soul survives. So, let's think about how many humans there are that have already been. Well, the universe, as we've said, for an Aristotelian is always the same. And the species of animals and plants are all the same. The human species has always existed. The universe of the plain universe. So, that means that the number of humans who have already lived and died is infinitely large. Gosh. And that means that there's an infinity of souls hanging around somehow now. Wow. So, so that gives you an actual infinity, which is something that the Aristotelians should want to rule out. That's a brilliant argument, actually. Yes. It's extraordinary.

I, I'm going to bring this in now because, um, in reading Al-Ghazali's arguments in The Incoherence of the Philosophers, there it is again. Do you recommend it? It's actually a fascinating read. Never seen. Every time someone buys one of the books, you should, you should try to demand, you know, five percent of the profit. Well, yeah, maybe I, I should. I'm interested to see if anyone does, but I hope they do, because it's worth having in one's library. But Al-Ghazali never seems to quote from the Quran as an authority to settle matters with his Muslim interlocutors like Ibn Sina, but he relies on purely rational arguments to refute them. My question is, why doesn't Al-Ghazali simply quote the Quran to settle his dispute with Ibn Sina? For example, and this is to do with the eternity of the universe, particularly, God says in the Quran, "God has created the heavens and the earth to manifest the truth." That's Quran 45:22. And he also says, "God says, 'We did not create heaven and earth and everything between them for no to no purpose.'" There is that is the opinion of those who disbelieve. That is 38:27. But I think that seems pretty clear that God did create the universe. It wasn't eternal. And here we have two people identifying as Muslims whose ultimate authority is God and His word. I'm just wondering why they didn't appeal to authority. It's not a fallacious argument if the authority is God, surely, because He is omniscient, to settle this dispute. So, why didn't they just short-circuit all this and go straight to God himself for the answer?

Yeah, right. That's a good question. I think there's a couple of reasons. So, one reason has to do with the project of The Incoherence of the Philosophers. Because all these works, so that, I mean, the words in Arabic in the title are *tahafut*, I mean, that's what's being translated here as incoherence, but it means something more like stumbling, right? Or places where the philosophers tried to maybe go forward too quickly and lost their way. That's what *tahafut* means. So, that is already a clue to what he's trying to do in the work in general, which is to show that their arguments don't work kind of for internal reasons, right? So, actually, although he could quote the Quran, and of course, in some sense, you're right, that his motive is because he thinks the Quran is inconsistent with the eternity of the universe, right? Actually, that's just not the point. The point is that these arguments actually don't work in and of themselves, right? So, it's an internal critique. That's the point of the book. And so quoting the Quran would be maybe something you might do to kind of set the context of the debate, but it wouldn't have to be, it wouldn't be part of the debate because the debate is about whether Ibn Sina's arguments work.

I mean, another way of thinking about that would be, suppose that you could mount a philosophical argument for a thesis which is inconsistent with the Quran, and the argument works, right? On its own terms. Rather, yeah, or it's like a proof. So, I mean, imagine it's like a mathematical proof, right? So, for example, suppose the Quran said that the diagonal of a square is commensurable with the sides. Which it does not. It's not right. So, I mean, of course, it doesn't say that. But imagine that it did. Would that be bad news for the Quran, or would it be bad news for geometry? Right? Yeah. Okay. Well, so here you might think, well, actually, if philosophy or reason proves that the universe is not eternal, and the Quran says that it is, is that bad for Islam, or is it bad for reason? Or what? Like, and, and so, I think one, one thing that's going on is Al-Ghazali, as a rational theologian, doesn't want to accept that reason or rational proofs might be inconsistent with the Quran, right? Because he, he wants to have reason and the Quran. So, that's one reason he's arguing on purely rational grounds. He wants to, in a way, um, avoid seeding the ground of rational argument to the philosophers, by which he means Ibn Sina. So, that's one reason.

Another reason, though, is that actually, if the lines you quoted from the Quran just now, Ibn Sina would say, "What are you talking about? I think that's true. God creates the universe. He creates it eternally." That's what creation is. So, in fact, he's, Ibn Sina says the theologians have this idea that creation means something used to not exist and then it started existing. And he says, basically, he doesn't put it this way, but he basically says that's that's a childish way of understanding what creation means. Creation means being a cause for something's existence, which means being a cause for its existence, whatever it exists, right? Making it exist and maintaining it in existence. So, it's not like God creates and then it's like, "Okay, I'm done, and now I can go on vacation." God creates the universe all the time, constantly, in every moment. And given that, and actually the theologians would agree with that, that the universe is permanently dependent on God. So, what Ibn Sina would say is, "Well, given that we agree that the universe depends causally on God at every moment when it exists, why are you additionally insisting that it had to start?" Because we agree that what God does is he creates the universe by maintaining its existence whenever it exists. Whether it's existed for an infinity of time or not is kind of irrelevant to whether God creates the universe, because God's creating the universe all the time, causing it to exist.

Well, I mean, I'm in a position to argue for the Quran in this sense. It just seems to me the Quran doesn't actually teach or indicate the eternity of the universe. It says it's created. So, I suppose in theory, Ibn Sina could be right because he's arguing from contingency. The universe is contingent. Doesn't necessarily happen to be finite. I guess I can see that. Ontologically dependent. But the Quran doesn't teach the eternity of the universe. Aristotle taught the eternity of the universe. So, he seems to be getting his concept from Aristotle rather than the Quran. The Quran doesn't naturally, it seems to me, teach that. Aristotle does. So, he's not really coming from the Quran. Therefore, the critique is, he's not being Islamically correct in his understanding of the universe in that sense. Right?

So, what I think what Ibn Sina would say, at least, is that the Quran teaches the radical dependence of the universe on God. That's not disputed. And he thinks, and he's got that in his system. Right? He has the universe being radically dependent on God eternally. Yeah. Um, and I, I guess he would also, by the way, say that the, the Quran teaches some things about God that are inconsistent with the idea that the universe is not eternal. For example, that God is perfectly wise. So, God is perfectly wise. Why is he kind of hanging around for an infinity of time and then only sort of randomly, arbitrarily deciding to create the universe on Wednesday, right? So, so this, or, and in part, and the other thing is the argument I gave before. So, he would say the Quran teaches the unchallengeable supremacy of God as a first cause who has no cause. And he says, well, if there, if God isn't creating the universe eternally, then is creating it with a first moment of time, which means there's some cause that has been brought to bear on him that makes him do that, as we said before. So, actually, I guess he would say, I mean, he's not really in the business of Quranic commentary. Not he, very occasionally, very, very occasionally, and usually in a pretty tendentious fashion, I think. So, I don't know which, I don't want to suggest that he's got a lot at stake in how to interpret the Quran, right? But if you pushed him on this, he would say he would certainly say that he's still being a good Muslim. And then he would say, "Well, if you want to know what the Quran means, because we all agree it needs to be interpreted, then the best way to resolve debates about what..."

It means would be to do some philosophy and find out what is actually true. By the way, that's even more explicitly said by Imrish later on, the commentator I've mentioned a few times. He actually wrote a work saying that the best interpreters of the Quran are the philosophers because they can check any interpretation against demonstration, and demonstrations can't be false. So, for example, if you can demonstrate the universe is not eternal, or sorry, if you can demonstrate that it is eternal, then you can't give any reading of the Quran that involves the Quran's claiming that the universe is not eternal.

Well, you say even Avicenna would have viewed himself as a good Muslim. But, uh, Al-Ghazali clearly didn't view him as a good Muslim, or Muslim at all. It seems, uh, you mentioned briefly earlier on that Al-Ghazali, um, tacked him, to use the Islamic expression, declared him to be a non-Muslim. And that's just not a theoretical judgment; that has legal, real-world, existential consequences. Now, of course, Ibn Sina had died long before Al-Ghazali, so Ibn Sina was in no risk of any action taken against him, of course. But he did declare him to be a non-Muslim. And why did he declare him to be a non-Muslim? And there's a very radical, radical, it's a very, very serious thing to do. Yeah.

And it's actually not just serious; it's also kind of unprecedented. Because, um, yeah, there's so someone who's done some good work on this is Frank Griffel, who's at Yale University. And he wrote a book called, in German, uh, about apostasy in Islam. Where he argues that because this moment where Ghazali accuses Ibn Sina of being an apostate is kind of a, like a step that hadn't been taken before in Islamic culture. Um, and in fact, in general, I think people have this sort of assumption about medieval philosophy in general, and Islamic medieval philosophy in particular, that there must have been like a lot of political or social or legal pressure on philosophers to conform to certain views, and that they would get killed if they stepped out of line or thrown in jail. But actually, that seems to have been not, not only is that an exaggeration, but it seems to be the reverse of the truth, isn't it? It's an orientalism that we have in, in the West, about, um, Islamic societies.

I'm reading, uh, Edward Said's book, *Orientalism*, at the moment. And, uh, extraordinary. Well, it's such a fun book to read. Uh, it investigates many of these, um, uh, mistaken conceptions of the Muslim world throughout history and today, of course, that, uh, uh, Western occidentalists have had. So this is another one, uh, which unfortunately is still quite common today. Yeah, I agree. And this is one of them. So, in fact, there really aren't any medieval philosophers in the Islamic world who were put in prison or put to death or in general harassed for their philosophical views. There's one philosopher who's a bit later than him who was executed, but that seems to be because he got into a political intrigue with members of Saladin's family, had him put to death. In any case.

Um, so what Ghazali does there is, at the end of *The Incoherence of the Philosophers*, he says that because Ibn Sina taught certain things that are inconsistent with Islam, he's effectively become an apostate. And the, uh, the penalty for that could be death. Um, I mean, apostate would usually mean someone who's converted from Islam to another religion, like Christianity, say, or like says they no longer accept the prophecy of Muhammad or something like that. But of course, Ibn Sina never said anything like that. He said things like the universe is eternal. Um, and he taught some other things that, that Ghazali thought were inconsistent with the Quran or with Islam. For example, um, Ibn Sina didn't accept bodily resurrection. He thought that we live on after death, but only as immaterial souls, as I was talking about before. So I agree, of course. Yeah, immortality was always straight from Hellenistic philosophy. Yeah, yeah, yeah. Right.

So on this basis, and some other, for other theses that Ibn Sina advanced, Al-Ghazali thought that he had effectively broken with Islam. But of course, as you said, this is not really an efficacious judgment on Ghazali's part, because Ibn Sina was already dead. I guess that what Ghazali was thinking is he was sort of laying down a marker: anyone who comes along and agrees with Ibn Sina about any of this can effectively be killed. Yes, legally. But in fact, I mean, Ghazali was extremely influential, and still is, as a theologian. But even after Ghazali says this, it doesn't seem to have any effect, really. So there are numerous philosophers in the century or two following who come along and just agree with Ibn Sina about all kinds of things, including the nature of the soul, the eternity of the world, whatever. Um, and even people who don't agree with him, they deal with the question kind of in the same way that Ghazali had in the first part of *The Incoherence* before he gets to this accusation of apostasy at the end. In other words, they kind of take apart the arguments and they think, okay, well, you know, like, are there good arguments against the eternity of the world? For the eternity of the world? What about all this infinity stuff? It gets very complicated, blah, blah, blah, blah. And you don't get the sense that, um, you certainly don't get the sense that it's, uh, like a topic that can no longer be rationally discussed. To the contrary, you have, you know, huge theological philosophical works that have, you know, 100-page long discussions of the eternity of the world, like weighing up the arguments for and against. So it just is something that gets more and more attention as it goes along.

But just, you know, I mean, you mentioned Averroes' response to *The Incoherence of the Philosophers*, *The Incoherence of the Incoherence*, somewhat conversely, called it. And then you mentioned all these other philosophers in the centuries after who continue to, uh, entertain the ideas of the, in terms of the universe. I was going to ask you, just how influential was Al-Ghazali's, uh, critique of Ibn Sina? It seems what you're saying wasn't influential at all, that people continued, these philosophers continued to argue, um, for the, for the eternity of the world. The impression I get, you know, as a layman, was of Al-Ghazali's supreme, dominant field. That you're saying, in fact, that maybe that's mistaken. There was actually quite a diverse range. Yeah, I think, I think he's influential as, certainly his arguments against the eternity of the world are influential. I think the idea that we're going to be able to stop people from saying this kind of thing by getting someone to come along and kill them all if they do that, that didn't happen, for sure. In part because, like, who's supposed to do that? So there's no established church in the Islamic world in the way that there is in Christian Europe, where there's no Pope, there's no bishops, right? Basically, what you've got is religious scholars and jurists, and then secular, um, you know, princes and warlords. And I just sort of what caused you that is at this very time, uh, or perhaps later on, after Al-Ghazali, who died in 1111 of the Common Era, there was a thing called the Inquisition. The Spanish Inquisition, but there was a, uh, other inquisitions, uh, uh, founded by the, the Catholic Church. But there was no, apart from one brief moment, uh, much earlier, to do with the Mu'tazilites or whatever, um, where they enforce orthodoxy on everyone, uh, you know, the createdness of the Quran and so on. That seems to be an exceptional episode in Islamic history, that there was no, normally there was no Inquisition kind of lurking, keeping everyone in check. In fact, there was quite open discourse, in contrast to the situation in Catholic Europe. Yeah, that's right.

I mean, I, I think actually the, the failure of what you're calling, what you're referring to there, from the 9th century, the *mihna*, where they tried to enforce the, the belief in the, um, createdness of the Quran, the fact that that was a complete disaster, maybe warned later political leaders from trying the same thing. We shouldn't, by the way, um, sort of paint too rosy a picture here. So, for example, if someone comes along and tries to convert Sunnis to Shiites in an area that's controlled by Sunnis, that could definitely get them in trouble. Yeah, yeah. Right. But so this is much more of a limited claim. So the point is that in general, it doesn't seem like political defense of orthodoxy was a constraint on philosophical inquiry in the Islamic world, the way that it actually was in the Latin Christian world. Although even there, probably wasn't as efficacious a form of mind control as that they were hoping and is often thought. Um, but in terms of like the, the, the, uh, influence of Ghazali on the, the actual debate, um, he, these are certainly works that continue to be read. So, for example, there's an episode from the early Ottoman period where two Ottoman scholars were given, were kind of like invited to perform in a contest where they judged whether Ghazali's arguments against Ibn Sina were good or not, right? And the, and the Sultan gave a prize to the person who gave the best evaluation. Wonderful. Yeah. And, um, I think, I think the guy wins a horse and a robe or something like that. 19th century or earlier? This must be something like that. That's a good question. I think it's something like 15th century. Yeah, very long time. Yeah, it's fairly early in the Ottoman period, right? Um, so, uh, so that's that's pretty cool. Um, also in the, in the area where Ibn Sina is active, which is Muslim Spain, you have quite a few discussions of the eternity of the eternity of the world. And not just by Ibn Rushd. And something that I find interesting and intriguing and kind of hard to explain is that there seems to be an emerging consensus in the Islamic Spanish context where people say, actually, the arguments for, against the eternity of the world are not really, um, decisive. Yeah. So you can argue, so Maimonides, in particular, the great Jewish philosopher, who's originally from Islamic Spain, but then moves with his family when he's young and winds up in Cairo. He, uh, he says, well, there's, there's arguments for the eternity of the world and against the eternity of the world, but none of them actually prove anything. They're just kind of maybe rhetorically convincing or dialectically convincing. So he says that the best strategy is to sh, is to prove that God exists on the assumption that the universe is eternal and on the assumption that it's not eternal, and you can get the same result either way. Um, so basically, you can use Aristotle's argument for God assuming the world is eternal, or you can say more quickly that if the universe was created and with the first moment in time, then God must have created it. And either way, you get God. So it doesn't matter, in a sense. There's a big scholarly controversy about what Maimonides' view actually was about this, but like, at least superficially, what he's saying is, well, it's hard to tell, but it doesn't matter because you can show that God exists either way. Another, um, Spanish Muslim philosopher named Ibn Tufayl, in a really interesting work called *Hayy ibn Yaqzan*, does the same thing. So he says, well, let's prove it with both assumptions. And this kind of, what you might call a kind of compromise view or ironic view, like, well, let's not try to figure it out, let's just show that God would have to exist either way. That's something that then got, um, kind of passed on to the Latin tradition, and Thomas Aquinas takes that position as well. So he says that they argue, yeah, so he says that the arguments for and against the eternity of the world, the rational arguments, are not decisive. We know from the Bible that the universe was created with a first moment in time because the Book of Genesis. Philosophically, you can't tell. Right, right. So the only way to know would be through revelation. Yes. Yeah.

Well, um, conclusion then, Peter. What are you working on at the moment? Anything, um, that we might expect to be published soon? Um, yeah, actually, um, so one thing it has a lot to do with what we were talking about with the, um, kind of response to Ghazali. So in the 12th and 13th centuries, so I've been running a project, uh, that's funded by the German Research Council, the DFG, Deutsche Forschungsgemeinschaft, uh, which is, uh, called "The Heirs of Avicenna." Heirs like H-E-I-R-S. So the sort of looking at the legacy of Ibn Sina and the 12th and 13th centuries. And we're producing a series of source books, which translate chunks of arguments on a whole range of different issues, including the eternity of the world, where Ibn Sina's views were debated by philosophers, kind of starting with Ghazali and then going on for the next couple of hundred years. Um, I mean, actually, they keep debating it for much more than 200 years, but this is the period we're looking at. So we're producing, uh, three volumes worth of, um, of source books, where we're translating lots of material from all the different authors who were alive then, and basically trying to point out that there's a kind of parallel development to what we see in with Latin scholasticism in Europe, where there's this massive argument-rich, very technical, very interesting body of philosophical literature which most people don't know about. And hopefully will make it accessible with the source books. So that's something that's coming. In German, though? No, no, in English. Or English. So the German Research Council is sponsoring you to do something in English? No, that's very open-minded. That's, uh, I didn't expect. We wouldn't do that. Oxford and Cambridge, we wouldn't produce something and then do it in Spanish or something. We would, it would only be in English. Um, I used to write in Latin at Oxford. Yeah, this is true. This is true. Uh, yes, past is a better analogy. Well, I think there's a, um, I think there's a rule here at my university that you can, you can submit your work in German, English, or Latin. Really? Can you hear church bells in the background? Are these university church bells? No, that's just my local church. Okay. I think it was just some medieval thing. Um, well, gosh, in Latin as well, even today. Um, so, well, thank you very much indeed, Peter, for your time, your expertise, your erudition, and your entertaining insights. Uh, it's fascinating. So I actually do recommend *The Incoherence of the Philosophers* by Al-Ghazali, in this translation, particularly Michael Marmura. I think it's the, uh, uh, the Brigham Young University Press, which, uh, I was going to say bizarrely, but I think they're the Mormon press. Um, so, but nevertheless, they are, um, mainstream, uh, publishers and do a lot of these. And you can read more of, uh, Ibn Sina, although he's known in the West as something slightly different, some of these points about the eternity of the world and so on in his *Metaphysics*, in that volume, translated by the same guy and published by the same press. So thank you again, Peter, for your time. Really appreciate. Thank you. Thanks for having me on again. Until next time.