Note: this transcription was produced by automatic voice recognition software. It has been corrected by hand, but may still contain errors. We are very grateful to Tim Wittenborg for his production of the automated transcripts and for the efforts of a team of volunteer listeners who corrected the texts.
Peter Adamson: So we're going to be talking about the Trinity and what various medieval philosophers suggested as ways of understanding the Trinity. But before we get into that specific issue, I wanted to ask you something more general, which is about sameness and difference. And the reason I want to start with that is that the Trinity seems like it's really a problem of sameness and difference. We want to say that there are three persons in the divine God, and these three persons are somehow distinct from one another, but they're also somehow the same or identical because the Father and the Son and the Holy Spirit are all one God. Would you say that's a fair assessment of the problem?
Richard Cross: I would say that's a very fair assessment of the problem and the thought that there might be some notion of sameness that's distinct from the notion of identity is probably a rather odd thought. But it's a thought I think which a number of medieval philosophers had. And oddly enough, they by and large worked it out exactly in the context of thinking of the theological problem itself. So whereas we might come to that particular distinction between sameness and identity in a very different way, they came to it from that angle. And here's the thing in a nutshell: We might be inclined to think that sameness and identity are the same relationship, but it looks like there are common or garden cases where it might not be. And one example which crops up frequently in the literature, I forget who originated it, would be the example of a bronze statue. So it looks like we have one object there, the bronze statue. But in fact, there's something rather curious about it because we can melt the bronze down and the statue is destroyed. But the lump of bronze, it seems to be the same lump of bronze. So it turns out that the lump and the statue have different, as we might say, persistence conditions. And that suggests very strongly that they're non-identical because things which are identical have all the same properties. And these two things seem not to have all the same properties.
Peter Adamson: So the basic idea here, just to make sure I got this straight, is that just as the father and son are non-identical because they're different persons of the Trinity, yet the same because they're the same god, the idea is that the bronze statue is the same as the bronze it's made of, but it's not identical. And so presumably we can say the same thing about difference. So I'm different from you. And what that means is that we're different in the sense of not being the same, but we're also non-identical. So everything that's not the same as something else is non-identical. But the case of the bronze statue is sort of weird because the bronze is the same as the statue is made of, but it's also non-identical.
Richard Cross: That's exactly right. So you're quite right about the application in the divine case. So this has cropped up quite a bit in modern literature on the Trinity and how people have typically thought about it is something like this: We think there's one god and we think there are three persons and we think that somehow this one god entity is shared by the three persons. And if we just take one of the persons, let's say the father, and we take the god substance, I'm going to call it the divine essence because that's how theologians like to talk. The divine essence relative to the Father is as the bronze is relative to the statue. It's somehow a constituent of that person in the way that we might think of the bronze as constituting the statue. The difference is - and some people think this is a terrible wrinkle, even if you can make sense of the notion of sameness without identity - is that the divine essence, the one god entity, is supposed to be able to constitute three persons simultaneously, which we don't think of so much in the case of the statue, but the bronze is just constituting the statue.
Peter Adamson: Yeah, to use another example, which I find quite illuminating, that's mentioned in something that you wrote about this: A hand is the same as a fist made out of the hand, but it's not identical. How can we tell? Well, because sometimes my hand unclenches and it's no longer a fist. But we can't really say that the same thing happens in the case of god because, of course, there's never a time when God is the Son but not the Father or vice versa.
Richard Cross: Yes, that's exactly right. And the divine case is hard for another reason as well. If we think about the bronze and the statue, and we wonder what it is that distinguishes the bronze from the statue, we might think, well, it's what we might call a modal property. The bronze can be melted down and survive, and the statue not. And so it's a can-be kind of property. So people who are inclined to think that the bronze and the statue are in fact identical would be inclined to think that you couldn't have things differing merely by modal properties. Now, nobody thinks that the modal property is anything like a quality that is, as it were, super added to the lump. It just sounds like a different way of describing the same thing. But in the divine case, there's another difficulty which is analogous to that, which has got to do with divine simplicity. So a lot of theologians are inclined to think that, well, the three persons, since they're non-identical, must be distinguished by something. But theologians, after Augustine, are inclined to think that there's nothing in God that explains anything, that explains any of the predications we might want to make in God, other than the divine essence itself. So a bit like the modal property in the statue, it looks like, you know, you've got a difference without a difference. And they think that they can say that. And perhaps their case is no harder than the case of the statue and the bronze.
Peter Adamson: But it does sound harder to me, because if you want to say that the divine essence explains Fatherhood, Sonhood, and Spirithood, that would be as if the bronze explained why it's a statue of a human, a statue of a horse, and a sphere or something.
Richard Cross: Yes, that's exactly right. And so some theologians in the Middle Ages thought that that really was just too mysterious, that you just couldn't have that amount of lack of an explanation. And so some theologians, starting really with Scotus and then people following him, thought that what you would have to say is that whatever distinguishes the divine persons from each other ought to be as real as the divine essences. So now we have some kind of complexity or composition, which is the price that gets paid. Still within the context of sameness with and without identity. But in this case, the non identities are explained, right, the distinctions are explained by additional properties or forms added on to or plugged into, as it were, the divine essence.
Peter Adamson: That's actually not that mysterious on the face of it. I mean, I'm a single human being, but I have more than one property, right? Yes. So I'm bald, I'm bearded, I'm a philosopher, to take sort of standard examples I like to use about myself. So I have these multiple properties and we don't have any difficulty with that. But I guess the difficulty is: what's the explanation for the different properties? So the explanation of my having a beard, whatever it is, it's not the same as the explanation of my being bald. That would be pretty strange, right? Because it would explain both why I have hair and why I don't have hair. Yes. And they're certainly not the same explanation of why I'm a philosopher. And you were saying that there are medieval theologians who wanted to say that it's the same explanation that explains why God is both a father and a son?
Richard Cross: Yes, though I think it's very controversial to think this. I think you might find this in Aquinas, for example, because the standard theological idea is that what's supposed to explain the distinctions between the persons is they're being related to each other in certain ways. That is to say that one is a father and the other is a son. And those are relational predicates. And then you make a very plausible move, which is that we shouldn't think of relations as anything like forms or properties, right? Super-added - they're just ways in which two things are towards each other. So Aquinas might well say, well, you know, the relation is nothing over and above the essence. And as soon as you made that move, you've got exactly the position that you were just describing, which Scotus thought was just absurd.
Peter Adamson: Because it doesn't do enough to explain the difference between the persons. It seems like in general, there's a Scylla and Charybdis kind of model here where, on the one hand, you don't want to violate divine simplicity. But on the other hand, you don't want to deny any real difference between the Trinity. And so is it would you say that it's generally the case that the different theological solutions flirt with one or the other of these two dangers to a greater or lesser extent?
Richard Cross: Yes, I would. I would say that very much. Historically, you find that the complete simplicity view largely in Western theologians after Augustine. I think the Eastern tradition generally was never as wedded to that. And so the Eastern tradition, for example, wants to make a distinction between the divine essence and what we might call, as they put it, things that surround the essence, which we might think of as divine attributes. So there's the divine essence somehow explaining the presence of a whole set of further additional, let's call them controversially 'form like' things that are features of the divine essence. The motivation behind this for the Eastern theologians, I mean, paradigm case Gregory of Nyssa back in the fourth century, was that we can know of God, and name of God, the things around the essence. But neither know nor name the essence itself. And Scotus, oddly enough, if you read him in his whole discussion of this, he picks up explicitly on an Eastern tradition in this case and thinks that - I really think if you pushed him, he would say that the Augustinian emphasis on complete divine simplicity was an aberration or a mistake. Basically he follows the Eastern theologians in thinking that we should distinguish between the essence and the attributes. Why? Among other things, because we should distinguish between the attributes themselves. There's got to be a distinction between God's wisdom and God's goodness because he doesn't see how wisdom could ever be identical to goodness.
Peter Adamson: Whereas some other theologians would say that's just an aspect of the limitation of human understanding that we think God's goodness and wisdom must be distinct. It's interesting there's a parallel to all this in the Islamic case because they don't obviously have the problem of the Trinity, but they do have this problem of divine attributes. But staying with the Christian tradition, since that's what I'm covering now in the podcast, let me ask you a bit more about Scotus because he's a thinker that you're very expert on. From what you've said so far about Scotus, it seems to me like the danger he's flirting with is going to be what might be called tri-theism. The idea that we've got three gods. We've succeeded in distinguishing the Father from the Son from the Holy Spirit. But oops, now there's three things instead of one or maybe it's even worse: Maybe there's four things like the three persons plus the divine essence. Maybe there's even seven things! Maybe there's the three persons, the property that individuates each of them plus the divine essence. Maybe we could go on. But anyway, more than one. So how does he seek to avoid that consequence?
Richard Cross: So in other words, the worry is that we've secured non-identity, but the price we paid is non-sameness. So here he appeals to something, a very different philosophical issue, and it's the theory of universals. That what we're trying to preserve in the divine case is that there's one divine substance and that self-identical entity is a constituent of three persons. Now, Scotus thinks that there's no other case where you would have three substance-like things, persons, constituted by one and the same substantial unit, right? In this case, God or the God entity, whatever we're going to call it. So Scotus accepts the view that there are shared universals, that is to say, I'll give you an example: a shared humanity that somehow explains how we are all human, a shared dogness that somehow explains how all dogs are dogs. But he doesn't think that in the creaturely case, that item, humanity, dogness, whatever it might be, has numerical unity. He thinks it has some other kind of unity, let's call it specific unity, that falls short of numerical unity. And so, of course, what we now can say in the divine case is, 'aha, here's something that seems to be a shared property that has itself numerical unity and identity, which wouldn't be the case for creatures.' Now, why would one think all of these things? He thinks we ought to posit such universals in the case of creatures because he thinks he needs an explanation or a ground for the fact that, say, all human beings resemble each other in certain salient ways. He thinks resemblance couldn't be a primitive property. He thinks that it couldn't have numerical unity because if it did, there really would be some sense in which we were all the same thing, because we would be in exactly the kind of relationship that the divine persons are. And self-evidently, we're not. And here's the argument: the divine persons aren't capable of doing distinct things because their actions somehow are all fundamentally attributed to or explained by the numerically singular divine essence, whereas we palpably can do different things. He thinks that the divine persons all share the same mental life. It's a rather curious thing, but it's a very common theological view because fundamentally their mental lives are the mental life of the divine substance entity, where it's clear we don't have shared mentality or shared activity.
Peter Adamson: Right. But isn't it still the case that the Father begets the Son and the Son doesn't beget the Father? So isn't that something the Father can and does do that the Son can't do? I mean, the Son doesn't beget himself.
Richard Cross: Yes, that's true. And Scotus has a very crafty solution to this. He thinks that... I'm not sure how good a solution this is actually. I mean, he thinks that all three persons share exactly the same causal powers. So the Son, like the Father, has a causal power to beget the Son. And there's a necessary block on the Son's ever exercising that causal power because that would make him a self-cause and nothing's a self-cause. But he has the power.
Peter Adamson: He has a necessarily unrealizable power. That does sound like Scotus. Okay, that's all good. The only thing is I'm not really seeing how that saves him from tri-theism because in fact the comparison to universals exacerbates my worry. So if we take you, me, and Buster Keaton, we've got three human beings. We're the same because we're all humans. But the whole point is that we're not the same human being and therefore we're not identical. So how does the comparison to universals help him say that the persons are non-identical but still the same? Because if we have three humans, we have both non-identity and non-sameness. So the universal comparison seems to actually suggest that there are three things rather than one thing.
Richard Cross: So the universals thing is only an analogy. And some theologians do talk about things like universals in this context. I don't think Scotus ever uses that word for the divine essence because his preferred word for what we nowadays would label universals is 'things which are common.' And what happens to things which are common is that they get shared out in different ways. And so the idea is that human nature gets shared out by being somehow divided up into numerically many instantiations. Whereas the divine essence doesn't get divided up in this way. So on a purely technical point, well, we should say the analogies are something that's common and not something that's universal. But I still see the force of the worry. And I think at that point, Scotus would go right back to where we started from. I think, 'aha, well, here we have a case where there's a relationship between the divine essence and the divine person that is akin to the relationship between the bronze and the statue.' And so we've got sameness between the essence and the person secured. And we simply iterate that.
Peter Adamson: I see. So it's like he wants to use the comparison to universals to explain the diversity or the non identity, but he wants to use the comparison to the bronze and the statue to get the sameness. So if you could hold those two things together in your head at the same time, then you've got the Trinity.
Richard Cross: Yes. Well, I think he had a capacious head. He could hold it all together quite nicely.
Peter Adamson: Right. Actually, that that leads me to a more general question about the Trinity, which is something that's always fascinated me about the subject, which is that all of these philosopher theologians, not only in the medieval period, but in late antiquity already with Augustine and Boethius. And after the medieval period. There's so many discussions about the Trinity and they're trying to make sense of the Trinity in some way. But on the other hand, it's also supposed to be, at some level, a mystery. And so something that always strikes me about it is that not always, but most of the time, what they want to do is explain the Trinity to a very high degree, but leave something unexplained so that it can remain mysterious. Is that what Scotus is trying to do? So is there anything that he thinks remains somehow beyond our comprehension about the Trinity? Or does he really think that he can give a rational account of what the Trinity is and why we should believe in it?
Richard Cross: He said he thinks that there's no mysterious third, as it were, leftover. I think he's got he thinks got the whole thing mapped out very nicely. He thinks he's done it just by using a metaphysical apparatus that is just part of his general toolkit for analysis of the material world. So he thinks he's got a theory of, let's say, the kinds of substance there could be that's maximally general, that uses the same analytical tools at the divine level and the creaturely level. And I think he thinks he's just got the whole thing licked.
Peter Adamson: So another slightly different question, though, it's one thing to give a rational account of the Trinity, and it's another to tell us that God is a Trinity. So maybe we can make a distinction here between how we discover that God is a Trinity, namely through Revelation, and then whether we can use reason to account for that. Would he say that we could use reason to discover that God is a Trinity, or is that something we only know through Revelation?
Richard Cross: Well, in most medieval theologians thought it was something you only knew through Revelation, and you can understand why they might think that. There were some who thought that, you know, rational reflection on some aspect of the created world could lead you to an argument in favour of the doctrine of the Trinity. The famous example is 12th century theologian Richard of Saint Victor, who started from, well, the datum that God was love. Suppose you could get that datum by rational reflection and not by revelation. He then thought you could show that love requires something, an object - that gets you two persons, and that perfect love requires those two objects themselves being united in their love for a third object, and that exhausted the kinds of love there were. So that would get you the three objects that you need to make this relationship work. And Scotus doesn't accept that argument. He does have some - he has some other rather bizarre arguments about the kinds of production that there could be. Scotus thinks that we could share about God that he's supremely perfect, and he thinks that amongst great-making or perfection inducing properties is being productive. So he thinks that you might want to say God's necessarily productive. The most perfect kinds of production would be something which resulted in something that was equal to yourself, supposing especially that you were an infinite being like God's supposed to be. And he thinks that there are necessarily just two kinds of production. One that is automatic and not the result of desire, and another which is, whether automatic or not, the result of desire. That gives us two kinds of production. He calls them natural and voluntary. And the most perfect being would be the most perfectly productive. That is to say, would produce an image of itself by natural production and an image of itself by voluntary production. And hey, presto, that gets you three!
Peter Adamson: So the Father is the producer, the Son is the thing produced naturally, and the Holy Spirit by voluntary action.
Richard Cross: And again, you'll notice that he's got that just from reflection on what he takes to be necessary metaphysical structures that we can just glean by observing the world.
Peter Adamson: Do you think that that was controversial? Did other people react to philosophers like Scotus by saying, 'hang on a second, you're trying to explain too much about this with reason?'
Richard Cross: No, I don't think they minded that. A lot of them did mind about the distinctions between, let's say, the divine essence and the attributes or the divine essence and the distinguishing personal properties. A lot of them minded about that because they've been taught, I think, from Augustine onwards, that you really shouldn't posit that much distinction in God. I think Scotus could quite reasonably talk to them. 'Well, really, if you can't have that much distinction in God, how on earth are you going to have three persons?'
Peter Adamson: So he'd basically just push back and say, 'yeah, you're insisting on simplicity so much that you're going to ruin the doctrine of the Trinity by saying that there's identity between the persons and not just sameness.'
Richard Cross: That's exactly right. And it was clearly controversial even when he was alive in Oxford around 1300. He first of all states that there must be this kind of distinction in God between the essence and the distinguishing properties. And he says something like, I forget the exact words. 'You can doubt it or you like, but that it's so, my intellect has no doubt.' A couple of years later, he puts forward exactly the same view and he says, 'I propose without asserting it and in default of any better view that...' and then he says exactly the same thing that he'd said earlier.
Peter Adamson: So he's started to have second thoughts.
Richard Cross: No, he hasn't. He's just covering his back. When he gets to he gets to Paris in about 1304, he states the same thing again, but not so assertively as 'I don't doubt it' and not so hesitantly as 'I don't assert it.' He asserts it without really trumpeting it.
Peter Adamson: But he thinks that the whole time?
Richard Cross: All the time - he doesn't see any alternative.