René Descartes - Meditation #5 - The Ontological Proof of God's Existence

Well, some triangles have right angles, and some don't, right? Like, um, you know, equilateral, uh, I don't know, some other... Some triangles don't have right angles. Whatever. Now, we're on Meditation 5, by Rene Descartes. Very quickly, though, here's a recap of what happened in the first four meditations. In Meditation 1, Descartes doubts away all of his beliefs. In Meditation 2, he concludes that he can know for certain that he exists, and that he's a thinking thing. Meditation 3, he offers that proof of the existence of God. That's the one that involves formal reality and objective reality and the idea of God in his mind that could only have come from God. Then, in Meditation 4, he confronts the problem of error. That is, he concluded that God exists, this all-perfect being, but the problem is, it seems like Descartes makes mistakes, and that's incompatible with the existence of God. Then he has a resolution to that problem, and the resolution, basically, is that the error comes from Descartes, uh, misusing the perfect mental faculties that God has given him. Okay, that brings us to Meditation 5. The main thing that happens in Meditation 5 is that we get a different proof for the existence of God. This is a very famous type of proof for the existence of God. Descartes gives us his own version of it. This type of proof is called an ontological proof. The word ontological just means having to do with existence, and all the proofs for the existence of God, or attempted proofs for the existence of God, have to do with existence. So, this is not a particularly helpful label. In order to understand this proof, we need to understand the notion of an essence, or, as Descartes sometimes calls it, a nature. The essence of something is a list of the qualities, or features, of that kind of thing that are essential. That is, that the thing has to have, it must have, in order to be the kind of thing that it is. Take, for example, a cat. Is being grumpy part of the essence of cathood? No. Because, although many cats are grumpy, maybe most cats are grumpy, there are some non-grumpy cats. Grumpiness is not essential to being a cat. It's not part of the essence. The same thing goes for, like, being stinky. Is being stinky part of the essence of cathood, or being a cat? No, because some cats are stinky and some cats aren't, and the non-stinky cats are still cats. But, being a mammal is part of the essence of being a cat. Because you need to be a mammal in order to be a cat. If you're not a mammal, you're definitely not a cat. Okay, so cats are the kind of thing that we discover in the world. Like, we look around us and we see cats in some places. But then there's the kinds of things that we don't discover in the world, like triangles. Triangles, as you may remember, are two-dimensional, three-sided polygons. And they don't exist. There aren't any triangles in the world, at least not in our universe. You've never seen a triangle. This is a bunch of ink on a piece of glass, right? The ink has three dimensions. The ink is made up of little particles and they have a certain amount of depth, right? But a triangle is supposed to be just two-dimensional. It has no depth at all. And all of the lines are perfectly straight. This is a drawing of a triangle. This is not a triangle. There are no triangles. You've never seen a triangle. We just stipulated, or made up, the idea of a triangle. We made it up. We decided, okay, it's going to be the polygon with three sides and we're going to call it a triangle. Even though we made it up, triangles have essences, just like cats have essences. Having a right angle... Let's say that this triangle has a right angle. Having a right angle is not part of the essence of being a triangle, because, well, some triangles have right angles and some don't, right? Like, you know, equilateral... I don't know, some other... Some triangles don't have right angles. Whatever. They're still triangles too. But having three sides, that is part of the essence of being a triangle. So the important thing to keep in mind here is that stipulated kinds, things that we just make up, we make up the idea of a triangle, we stipulate it, they have essences too. That's important. This proof for the existence of God, it requires some claims about God's essence. Instead of explaining how the proof goes, though, let's just read what Descartes says. This happens on A.T. 65. That was it. That was a proof of the existence of God. Did you catch it? When I teach this material in an actual physical classroom, what happens is that I'll ask the class, does everyone understand the proof? And some of them will say, And other students who definitely do not understand what just happened because it was very fast and very condensed will look around and see that there's other students who seem to understand what's going on and so they'll just keep their mouths shut. Don't do that. Don't live your life pretending like you know what's going on and hoping that no one is going to stare at you or notice you or notice that you're faking it. Don't fake it. That's not a way to live your life. It'll eat you up inside and you'll die alone. So let's just try to explain what happened in those three sentences. Let's start by looking at a geometrical proof or a proof having to do with triangles. One, having three sides is part of a triangle's essence. Okay, so we've never experienced triangles. We didn't find them in the world. We just stipulated the definition of a triangle and this is part of that definition, right? A fact about the essence of triangles is part of the definition of triangles. It's having three sides. Step two, all polygons with three sides have three angles. This is just sort of a straightforward fact of geometry. If you're a polygon and you have three sides, then you have three angles. That's supposed to be just a straightforward fact of geometry. Step three, therefore, these three dots mean therefore, having three angles is part of a triangle's essence. Okay, this just follows from one and two, right? If having three sides is part of a triangle's essence and everything with three sides has three angles, then having three angles is part of a triangle's essence. And by part of a triangle's essence, we just mean it's a necessary part. It must be the case that if you're a triangle, you have three angles. And then step four, therefore, a triangle necessarily has three angles. Right? Necessarily just means must be. It must be that a triangle, if something is a triangle, it has three angles. Okay, this proof works. We just stipulated this. This is a straightforward fact of geometry. This follows from one and two. And this, step four, this follows from three and just sort of the nature of an essence, what an essence is. An essence is the essential or necessary qualities of a thing. That's a perfectly good proof having to do with triangles. The proof for the existence of God, as you're about to see, the one that Descartes gives in Meditation 5, works just like this. Here's what to look out for. The proof for the existence of God is apparently going to work in exactly the same way. So it's really hard to see how this proof could work so well and this proof for the existence of God could somehow fail. Here's the proof. Having all of the perfections is part of God's essence. This is just the stipulated definition of God. God is just defined for Descartes and we're just making up the definition in the same way that we make up the definition of a triangle. God is just going to be defined as the creature, the potential creature, that has all of the good things. Perfection just means a thing that it's good to have. So God has all of those qualities, all the good things, like being nice and being strong and powerful and being knowledgeable, knowing all the facts. God has all of these qualities maxed out. Any quality that it's good to have, God has it and has it to the maximum degree. Having all of the perfections is part of the essence of God. Yeah, that just comes from the definition of God the same way that having three sides comes from the definition of a triangle. And just like we could know this fact about the essence or the definition of a triangle without ever experiencing a triangle, we can know this fact about the definition or the essence of God without ever experiencing God. It's just stipulated. Step two, existence is a perfection. This is supposed to be a straightforward fact about perfections. That is, existing is a good thing. Existence is a quality that some things have and other things don't and it's good to exist, so existence is a perfection. Existence is one of those things like being all-powerful or all-knowing or kind or whatever. Existence is one of those perfections. That's step two. Just like this fact about all polygons with three sides having three angles is supposed to be just a straightforward fact of geometry, this is supposed to be just a straightforward fact about what's perfect. Step three, therefore, these three dots are just shorthand for therefore, therefore, existence is part of God's essence. Existing, being a real thing in the universe, is an essential feature of God. This is just supposed to follow from one and two in the same way that the fact that having three angles is part of a triangle's essence is just a straightforward conclusion that follows from one and two. So, here we are. Existence is part of God's essence. God has all the perfections. Existence is one of the perfections. So, God has existence. Essentially. Necessarily. And that gives us four. Therefore, God necessarily exists. Step four is just supposed to follow from step three and the nature of an essence. Necessarily just means it must be. God must exist. God necessarily exists. God does, therefore, exist. That's the proof for the existence of God. It's called the ontological proof. Descartes, by the way, wasn't the first philosopher to come up with a proof like this. It had been around for a while. I don't actually know who is credited with being the first person to come up with this proof for the existence of God. And probably that person who's credited with it wasn't really the person who was really the first person to come up with it. But anyway, this is a very famous proof for the existence of God. It might seem too easy, like it was too quick. But the thing is, this proof works. This is a good geometrical proof. So, either there's an important difference between this proof and this one, or God exists. One thing that's been said in response to the ontological proof, this is something that was pointed out by a philosopher called Gaunilo. He was a contemporary of Descartes. That is, he lived at the same time as Descartes. He just said, look, this is too powerful of a proof. It seemingly can prove that many, many, many things exist that don't exist. The example that Gaunilo gave was of a perfect island. We just make up the definition of a perfect island as an island that has all of the perfections, and then existence is a perfection, so existence is part of the essence of this island, so this perfect island exists, necessarily. That seems crazy. We can't just prove the existence of islands by making up some definitions. The point is, there's got to be something wrong here. This just seems way too powerful of a type of proof. I believe that Descartes actually, not in the Meditations, but responded to this by suggesting that you can't just have some of the perfections. You can't have a thing that's like an island, so it's not like an all-perfect entity. It just has a few perfections that you add into the definition, like existence or whatever. It either needs to be an all-perfect thing, an all-perfect creature that's all-powerful and all-knowing and all-good, or it can't have any of the perfections or something like that. I think Descartes responds in that way. One problem that occurs to me, I'm sure that other people have thought of this before, but this just came into my mind, is that that response is a little in tension with what Descartes says in Meditation I, when he raises the possibility of a malicious demon. The whole idea of a malicious demon is a creature that has at least one of the perfections maxed out, that is, omnipotence, it's all-powerful, but it lacks another perfection, that is, it's not all-good. It's a malicious creature that is as powerful as God. That was the suggestion from Meditation I, that such a creature like that might exist. And it seems like, in responding to Gaunilo, Descartes is assuming that actually such a creature couldn't exist. Anyway, another famous response to this ontological proof, many philosophers take this to be the decisive response, that is, it shows that this proof really doesn't work, although it looks like it comes from Immanuel Kant. Kant was a Prussian philosopher who lived, I think, from 1724 to 1804 or something like that. His point was, this premise, premise number two, is just false. Whereas it's true that all polygons with three sides have three angles, it's just not true that existence is a perfection. The suggestion that Kant made was that existence is not even a predicate. Like, existence isn't even a property of things. Well, here's an example. So, take the following sentence. I don't know. Kim smokes. Kim, I'm thinking of Kim Kardashian. I don't know if she smokes cigarettes. I assume she doesn't, actually, from what I know about her. But anyway, this sentence, it has a subject and a predicate. Kim smokes. Kim is the subject, and then the predicate says something about her. It says that she's a smoker. Then take this sentence. Kim exists. It looks like this sentence is just like this sentence. You've got a subject and a predicate. There's the subject, Kim, and then Kim has some quality or feature or there's something about her that we can say, namely, that she exists. These look, on the surface, like they work the same way. Kant's point is that that's an illusion. Really, the sentence, Kim exists, is not picking out a subject and then saying something about that subject. Rather, you should understand this sentence as being fundamentally structured in the following way. There exists a Kim, or there exists something and that thing is Kim, or whatever. That's what's really going on with this sentence. The idea is that existence is not a quality of something. It's the precondition for having any qualities at all. So, Kant wants to suggest that this premise is false. Anyway, the point of this video is not to really attack this argument that Descartes gives in Meditation 5. Rather, the point is just to get the argument out, to draw it out of the text and explain what's going on in the Fifth Meditation. So, let's just go back to those three sentences that I read before and I'm going to read them again. And what I want you to do this time is see that I'm not lying. See that this proof is really in there. Here's the text one more time. Certainly, the idea of God, or a supremely perfect being, is one which I find within me, just as surely as the idea of any shape or number. Okay, actually, I'm not going to read through the whole thing yet. We're going to pause there. That's got all the ingredients that we need for premise one. Having all of the perfections is part of God's essence, right? A supremely perfect being. Descartes says, just like I've got the idea of the essence of a triangle or the nature of a triangle, I have the idea of a triangle in my mind, so too I have the idea of God in my mind, and that idea is the idea of an all-perfect being. Okay. Then he says, and my understanding that it belongs to his nature, God's nature, that it belongs to his nature, that he always exists, is no less clear and distinct than is the case when I prove of any shape or number that some property belongs to its nature. Existence is part of God's essence. Descartes skipped over step two here, right? Or sort of meshed in with step three, but what he's saying there is just that, look, just like I prove that triangles or numbers have certain properties or features, I can straightforwardly prove that existence is part of God's essence. Hence, even if it turned out that not everything on which I have meditated in these past days is true, I ought still to regard the existence of God as having at least the same level of certainty as I have hitherto attributed to the truths of mathematics. That's the conclusion. God exists, and he can know that with as much confidence as he knows that triangles have three angles. That's meditation five. In meditation six, Descartes is going to prove that the physical world around him exists, and then he's going to prove that the mind is distinct from the body, and then he's going to be done, then the meditations are over.