← Defenders Podcast
Loading summary
Transcript34 lines
- [00:04]
A
Welcome to Defenders, the teaching class of Dr. William Lane Craig. Today An Excursus on Natural Theology, Part 23. For more resources from Dr. Craig, go to reasonablefaith.org in our Excursus on Natural Theology, we've talked about a number of arguments for God's existence, such as the argument from contingency, the Kalam cosmological argument, the argument from the fine tuning of the universe, the moral argument. Today we turn to a new argument and the last that we'll be surveying in our class. And this is the ontological argument for God's existence. And we have a handout available for this if you need it, raise your hand and Marion will get a handout to you. For in the year 1078, a Benedictine monk by the name of Anselm, who later became the Archbishop of Canterbury, formulated a new and bold argument for the existence of God, which has now fascinated philosophers for a millennium. A year earlier, in 1077, Anselm had finished writing a treatise called the Monologium, in which he presented cosmological and moral arguments for God's existence. But Anselm was dissatisfied with the complexity of the case for theism that he had developed, and he wanted to find a single argument which would prove that God, with all of his attributes, in all of his greatness, exists. And he had pretty much given up on the task when he came upon the definition of God. Ah, thank you, Marian. The definition of God in Latin as aliquid quo nihil maeus cogitare posit. The Latin is so great. See, you can learn this phrase and impress your friends when they ask you for a definition of God. Ali quid posit. That is to say, God is something than which nothing greater can be conceived. Or in more idiomatic English, God is the greatest conceivable being. And Anselm argued that once in his treatise. Then that followed the Proslogium, that once you understand the definition of God, once you understand what God is, then you, if you've really understood it, will see that God must exist. Because if God did not exist, he would not be the greatest conceivable being. A greatest conceivable being must be an existent being, otherwise it wouldn't be the greatest. So God's existence is inconceivable for anybody who really understands the word God and understands what God is. And Anselm says that's why Psalm 14:1 says, the fool hath said in his heart there is no God, because if that person really understood the word God, then he would See that God must exist, and so he's a fool for saying that the greatest conceivable being does not exist. Now, Anselm's argument came to be known as the ontological argument, which is from the Greek word ontos, meaning being. It went on to assume a variety of different forms and has been defended by some of the greatest thinkers in the history of philosophy, for example, John Duns, Scotus, Rene Descartes, Benedict De Spinoza, Gottfried Wilhelm Leibniz, and so on. What is the common thread in all of these different versions of the argument that unites them and makes them ontological arguments? Well, I think the common thread among these various ontological arguments is that they all try to deduce the existence of God by from the very concept of God, together with some necessary truths. Proponents of the ontological argument in its various forms maintain that once we understand what God is, once you have an adequate conception of God, whether the greatest conceivable being or the most perfect being, or the most real being, then we will see that such a being must in fact exist. Now, this argument has tended to sharply polarize philosophers. For example, the 19th century German philosopher Arthur Schopenhauer characterized the ontological argument as a charming joke. And that opinion is certainly shared by many other philosophers today. On the other hand, the argument has been taken very seriously and in fact defended as sound by quite A number of 20th century philosophers who are of some prominence as well, notably Norman Malcolm, Charles Hartshorn and Alvin Plantinga. Since Plantinge's version of the argument is, I think, the most sophisticated and the most recent development of the argument, we'll use it as the springboard for our discussion of the ontological argument. Now in Plattinga's version of the argument, he appropriates the insight of Gottfried Wilhelm Leibniz that the ontological argument assumes that the concept of God is possible. That is to say, the argument assumes that the concept God or the greatest conceivable being is a coherent concept. Or using the semantics of possible worlds, it assumes that there is a possible world in which God exists. Now, for those who are unfamiliar with with the semantics of possible worlds, let me just say a word of explanation about this. Lest we be misled. When we talk about possible worlds, we do not mean planets or even other universes. Rather, a possible world is simply a maximal description of reality. It's a way reality might be. I think the easiest way to think about a possible world is as a huge conjunction of propositions, P and Q and R and s and so on. And these individual conjuncts, P, Q, R, S, are propositions which can be true or false. And a possible world is a conjunction which comprises every proposition, or it's contradictory so that it yields a maximal description of reality. Nothing is left out of such a description. And by negating different conjuncts or propositions, we can arrive at different possible worlds. So, for example, we could call W1 this description of the world, P and Q and R and S. But another description of the world would be W2, and that might be P and not Q and R and not S and so forth. W3 would be another possible world, and this might be not P and Q and not R and S and so forth, or W4, which could be not P and not Q and R and not S. These would continue being the range of possible worlds. Only one of these descriptions will be comprised of propositions or conjuncts, all of which are true and so is the true description of the way reality actually is. And that description we will dignify by saying it is the possible or it is the actual world. So one of these will have all true conjuncts and that will be the actual world. Now let me pause at this point and ask if there's any question of a comprehension type nature about what possible worlds are. Yes, Ben?
- [10:05]
B
Okay. This has always been the argument for God that I've had the hardest time wrapping my head around. So I just want to be sure that I'm clear so far. So this is different than the multi world hypothesis because we're not saying each of these are actual worlds out there somewhere. We're saying we're talking about one single actual world. And these are all the different ways it could have been, although only one of them is correct. So it's completely different than the multi world.
- [10:31]
A
Right? This is different than the multiverse hypothesis or the many worlds hypothesis in cosmology or quantum physics here. As I say, just think of these worlds as descriptions, just big conjunctions like Ben Jones exists, Cindy Fox exists, Bryant Wright exists, William Craig exists. That's all this is. It's just a big description. And the description that is true is the actual world.
- [11:04]
B
Okay, okay, I got that.
- [11:05]
A
Yeah. Taylor, in order to get rid of a possible world as a possible world is the only way that we can do that, to find a contradiction within. That's a good question, and I'll say something about that in a minute. These propositions obviously have to be compossible. They have to be able to both be true in the same world. Right. Otherwise that's an impossible world. So that's not a possible world. But they also need to be possible in and of themselves. The proposition itself needs to be possible, and I'll say something about that in a moment. So you need to have both, each conjunct being possible in itself and then you need their combination to be possible to be a possible world as well. Brad, that's exactly what I, I was going to ask. What do you mean by possible? What are the underlying assumptions of possible? Yes, okay, this is a really good question. And it's probably impossible to define it. No, you can't use that because it's a sort of primitive concept. But the idea would be actualizable or realizable. This is something that really could exist, really could be actual. Does that help? Given maybe the laws of physics of. No, no, not the laws of physics. That would. Okay, Brad, good question. There are different types of modality, aren't there? And one of these would be what we might call physical modality. And Brad says that something would be physically possible if it's consistent with the laws of nature and be physically impossible if it contradicts the laws of nature. But that's a fairly narrow kind of modality. There are things which might not be physically possible, but they're still logically possible. And so the kind of modality that is at play here, Brad, is again this sort of ill defined type of modality called broadly logical modality. So we're talking about broadly logical possibility and necessity. And again, what does one mean by that? One means that something is broadly logically possible if it's actualizable or realizable. If it could really be real, then that will be something that's broadly logically possible. Sometimes this is called metaphysical possibility and necessity, that's another label. But it's still the same idea, is that it's something that's realizable. Yes, Bob.
- [13:53]
C
Bill, as you will probably remember, I've never thought this was a very good argument. One of the. And we'll get down to. I guess my core complaint is that other so called possible worlds are not possible. Okay? There's only one world possible and that's this one. The only way you could get another world would be to get a creator as a theist, you and I, to do that. Well, to try to get God to make another possible world, say that had an orange sky instead of a blue sky, or which one of us didn't exist or did exist, I would say is imaginative and fanciful. In other words, just because you can imagine, which is what these philosophers is doing. These other worlds doesn't mean there's any way that any other world but this one could possibly be a reality. So that's why I would never evoke this argument.
- [14:44]
A
We've been around this block before, Bob, and I think you just don't get it in terms of what. What you're expressing is a kind of logical fatalism where everything that is true is necessarily true and there are no possibilities. So on your view, it's impossible, for example, that God might have refrained from creating the world, or it's impossible that Peter not deny Christ three times, or it's impossible that the second person of the Trinity take on a human nature one second later than he did in Mary's womb. And those just seem to be utterly implausible sorts of assertions and would really deny God's freedom. It would mean that God has no logical possibilities either. So as long as we're not conceiving of these things as actual worlds someplace, but simply as ways the world could have been, surely there are contingencies, there are possibilities, and, and some of these concern God himself. And if you deny that, you land in a kind of logical fatalism, even concerning God, where everything that happens, happens necessarily. And that to me just seems obviously mistaken and also theologically pernicious. It would make evil necessary, for example.
- [16:19]
C
Well, those are not my attitudes, and I don't think that they necessarily flow from my position. I don't see how that flows, how a logical fatalism flows from.
- [16:29]
A
But Bob, you said there's only one logically possible world, this one.
- [16:35]
C
Well, now, I don't know what you mean by logically possible.
- [16:38]
A
Right.
- [16:39]
C
That's why I said logic is of this world.
- [16:41]
A
So, yeah, see, that's why I said. I don't think you get it here. The idea is, as I said to Brad, that we're talking here about something that's realizable, actualizable. This reality could be that way, and freedom on God's part would surely necessitate.
- [17:01]
C
Of course, my God has the freedom to create any world he wanted. But the fact is he did not. That's what I'm saying. And any of these other worlds, he did not do that. For various reasons known only to him and his sovereignty, he chose not to do that. Now, I can imagine, what if he did? What if he didn't? But see, that's fanciful to me and, and not really based in reality.
- [17:23]
A
These other worlds are not real. That's right. But they are ways. The world could have been. And I think you want to admit that. I mean, you want to say God has the freedom to do differently, but he could have done differently.
- [17:38]
C
I would say they could not have been because he chose not to do it, and therefore they could not have been. Had he chose to do it, then, yes, it would be reality.
- [17:47]
A
All right, let's go to Dennis here, and then we'll go to Cindy.
- [17:49]
D
My understanding of this is that it's just a concept for philosophical discourse, and it is to answer the what ifs of your debate opponent. Because otherwise it would not be possible to argue the ontological argument unless you could answer the what ifs. You know, if your debate opponent says, well, how can you say there is a maximally great being if, you know, if the world could have made itself or something like that, if we lived in a universe where things popped into existence out of nothing and we could demonstrate that, then that would, you know, we wouldn't be able. I'm saying what a debate upon it might say about that. It answers the what if.
- [18:34]
A
It seems to me that whether in debate or even just in your own thinking, we entertain possibilities all the time. This is especially true when we deliberate about what we're going to do. And we think that there are real possibilities that we have the freedom to actualize or not. And possible worlds, as you say, is just a way of conceptualizing this. I look at it as a sort of heuristic device. It plays the same role that diagrams do in mathematics textbooks. They simply are ways of representing it. So to say that something is possible, like it's possible that Christ could have been born one second later to represent that. You say there's a possible world in which Christ was born one second later. And it's just a visual aid, if you will, of thinking about possibilities and necessities. And it's a very helpful heuristic device. Because many of these questions would be very difficult to entertain and think about without these sort of illustrations.
- [19:46]
D
It's a way of considering counterfactuals.
- [19:49]
A
Those play a role in this, too. That's right, counterfactuals. Like you said, if I were rich, then I would do this or that. Those involve possible worlds. That's right. Okay, let's have Cindy weigh in here. Wait, we're going to get you the microphone so we can all hear.
- [20:06]
E
I'm just wondering if it's not the use of worlds which is tangible, causing confusion. I mean, it's possible that God created this planet or our existence without mongooses. He didn't, but he could have. And I think that would be an example of a possible world. But is it because we're using that word that it's causing confusion? Because we're not thinking of it as a concept anymore. We're trying to put reality into it.
- [20:37]
A
Yeah, that's absolutely right. And that was why I said, when we talk about possible worlds, we don't mean planets or universes. We just mean a description. I mean, just think of this list, and these are just propositions. It's a big, long conjunction of everything that's true or false. That's what it is. And you call that a world, and then one of those is true. One of these conjunctions has all true conjuncts in it, and you call that one the actual world. So it's just a description.
- [21:12]
E
To you, it's a world. To me, it's a possibility.
- [21:15]
A
That's fine. That's fine. It's a possible world, right? Yeah. In the Zangmeister video that Zangmeister is developing right now for the ontological argument, the way he's chosen to portray possible worlds in order to avoid this misunderstanding is very clever. Rather than using circles or globes that look like worlds, he uses doors. And he shows how you open one door, and inside there's unicorns and pink elephant and open another door, and there's something else in there. And I thought that's very nice, because it avoids this idea of universes or multiverse, that kind of thing. All right, some other question about this concept. Yes, Steve, at this point in the discussion, do any of those P's and Q's and, you know, R's, does that include, you know, God's existence? Yes. Yes, quite definitely, Steve. I mean, now, we haven't gotten to that yet, but let's let R equal the proposition God exists. Okay, so in W1, that proposition is true. Right? Because it says r. But in W3, that proposition is false because it says not. Rich. So here we have a case where in possible world one, God exists, but in possible world three, God does not exist. So. That's quite right. It's a maximal description of reality. So it will include propositions like God exists. Yeah.
- [23:00]
F
Okay, Travis, how with the ontological argument, do you stay on track with it being ontological? Because I think if you. If you go to the world saying everybody thinks of it as a physical world, if you go to say God exists, like, for instance, in a world, design can't exist without a designer, therefore it's God. But then you have the Design argument or like if you go into cosmological with there's a universe and not nothing, then you have the cosmological argument. So how. I think, I think one of the biggest difficulties that I've seen with ontological is that it's difficult to stay strictly philosophical.
- [23:37]
A
Uh huh. Well, I hope that when we look at the premises of planning his argument that that will help us to stay on track because he lists the steps very explicitly. And the way the argument moves is that if it's possible that God exists, then God does exist. And that will be the move that it makes from the, from the mere possibility of God's existence. It will follow that God actually does exist. So that's how it will reason and we'll see whether or not that's a good argument. Okay, Any other comprehension type question before we close? Yes, Mark. I thought you said earlier that Anselm was saying that God is the greatest conceivable being. And then I looked up what I had written translation from Anselm and it said greater than can be conceived. Did I hear that wrong? God is that than which nothing greater can be conceived. Okay, that was his definition. Aliquid quo nihil mae us cogitari posit that than which nothing greater can be conceived. Or more idiomatically, a greatest conceivable being. That's what God is. If you could conceive of something greater than God, then that would be God. So by definition Anselm says God is the greatest conceivable being. Kate Taewon. So the conceivability
- [25:14]
E
limits God.
- [25:17]
A
Yes, insofar as if the concept of God is incoherent, then God cannot exist. If the concept of God is like the concept of a married bachelor, then God cannot exist. So that's the insight that I mentioned that Leibniz had. Leibniz said the argument is assuming that the concept of God is a coherent concept. It assumes that the concept of God is. Is possibly instantiated. That there's a possible world in which God exists is true.
- [25:59]
E
What I'm trying to say is conceivability
- [26:03]
A
is a human element.
- [26:07]
E
So basically that is the limitation of who.
- [26:13]
A
All right, now let's. Here I want to go back to what Bob said because he made a distinction, I think that is a nice one, between what we can imagine and what we can conceive. We're not saying that God is the greatest imaginable being because that would be limited to human imagination. But the idea of greatest being conceivable is the idea of a being which it is logically impossible for there to be something greater than it. And there is a difference between imaginability and conceivability. For example, I can conceive mathematically of a thousand sided polygon. I can think of a geometrical figure that has a thousand sides. It's not difficult to conceive, but I can't imagine such a thing. I can't form any kind of visual image of a thousand sided polygon. So that would be an example of something that's conceivable even though it's unimaginable. So we're not saying that God is limited by human imagination, but simply that God is the logically greatest being that can exist. And if that concept is incoherent, then God cannot exist. So we'll see how that actually plays a very, very crucial role in the argument. All right, well, let's have a benediction and we will close our class today. And now, may the God in whom nothing greater can be conceived go with you this week and fill your lives with a sense of his greatness, his majesty and his glory through Jesus Christ our Lord. Amen. The copyright for the content of this recording is held by Dr. Paul William Lane Craig. For more go to reasonablefaith.
- [28:11]
C
Org.