Existence of God (part 2)
Transcript of William Lane Craig's Defenders 2 class.
Excursus: Natural Theology
§ I. Contingency Argument
We began last time by looking at a new section on natural theology or arguments for the existence of God that do not appeal to God’s special revelation. We started off with the Argument from Contingency that Leibniz developed. It was very simple and goes something like this:
1. Everything that exists has an explanation of its existence.
2. If the universe has an explanation of its existence, that explanation is God.
3. The universe exists.
And we saw that from the premises it follows that:
4. The universe has an explanation of its existence.
5. That explanation is God.
This is a logically airtight argument – the conclusion follows according to the rules of logic. The only question is the truth of the premises. Premise 3 is undeniable for any sincere inquirer after truth, so the question is premises 1 and 2 – are these more plausibly true than false?
Necessity and Contingency
At first blush, premise 1 seems open to a very obvious objection. The skeptic might say, “If everything that exists has an explanation of its existence, what about God? God exists, according to you Christians at least, so it would follow that God has an explanation of his existence. But that is impossible – there can’t be something higher than God that explains why God exists. By definition, God is the greatest being, so it is impossible for God to have an explanation of his existence. Therefore, premise 1 must be false.” And if the Christian or the theist says that God just exists with no explanation of his existence, the skeptic would then say, “Why not just stop with the universe? That is, the universe just exists inexplicably. If you can say God exists without an explanation, then why can’t you just say the universe can exist without an explanation? Why go to God?” Thus, we reach a stalemate between the theist and the atheist at this point.
How might one respond to that objection? The objection is, in fact, based upon a misunderstanding of what Leibniz meant by “an explanation.” In Leibniz’ view, there are two kinds of things. On the one hand, there are things that exist necessarily. On the other hand, there are things which are produced by some external cause. Let me explain this.
First of all, things which exist necessarily simply exist by a necessity of their own nature. It is impossible for them not to exist. They must exist. What would be examples of things like that? Many mathematicians think that numbers and sets and other mathematical objects exist in this way. If these things exist, they just exist necessarily by a necessity of their own nature. There isn’t any cause of the existence of these mathematical entities; they just exist by a necessity of their own nature.
By contrast, things that are caused to exist by something else don’t exist necessarily. They exist because something else has produced them in being. Examples would be things like chairs and people and planets and galaxies. These all have causes of their existence that explain why they exist.
So, when Leibniz says everything that exists has an explanation of its existence, the explanation may be found either in the necessity of the thing’s own nature or else in an external cause.1
So premise 1 could actually be reworded or expanded more perspicuously (precisely) in this way:
1. Every existing thing has an explanation of its existence, either in the necessity of its own nature or in an external cause.
Once we understand the premise in its fullness, then the objection that we are considering falls immediately to the ground because, in this case, God does have an explanation of his existence, namely, God exists by the necessity of his own nature. God exists necessarily – it is impossible for him to fail to exist. Even the atheist recognizes that it is impossible for God to have an external cause – it is impossible for God to be caused by something outside of him. The explanation of God’s existence must be that he exists simply by a necessity of his own nature.
So Leibniz’s argument is really an argument for the existence of God as a necessary, uncaused being. It connects very nicely with the section we did on the attributes of God where we talked about God’s aseity (or self-existence) and necessity. Leibniz’s argument is precisely for the concept of an uncaused and necessary being. Therefore, far from undermining Leibniz’s argument, the atheist objection to premise 1 actually clarifies and magnifies who God is. If God exists, he is a necessarily existing, uncaused being.
Question: Can you give an example, other than God, for something that would exist necessarily?
Answer: As a Christian, I think that God is, in fact, the only necessarily existing being. So I think he is unique in that sense. But I can say to you that certain philosophers have thought that things like numbers exist necessarily. Others have said things like propositions exist necessarily. A proposition is the information content of a sentence. For example, the sentence “Snow is white” and the sentence “Der Schnee ist weiß” are two different sentences. They have no words in common, and they aren’t even in the same language, but they both express the same proposition, namely that snow is white. So some philosophers would say that propositions exist necessarily. Others would say properties exist necessarily. Things like the brownness of the dog, or the hardness of the surface of the table are necessary entities. There are all sorts of entities that philosophers have identified as existing necessarily. Obviously, these are rather exotic sorts of entities, but that is simply because by the nature of the case most things we are familiar with in the physical world don’t exist necessarily. So I am sorry that the examples are exotic, but that’s just the nature of the case.
Followup: I agree with this – I see God is just because he is. I can’t see that for anything else. For example, in the case for numbers, you have to have something to count. If I were to count 1, 2, 3, I would need something to count.
Answer: I appreciate that. You are getting into the question whether numbers exist or not. Let me just say that there are a good number of philosophers in the history of thought who disagree with that. They think that even if there are not three concrete objects, like three pebbles or three stars or three atoms, they would say nevertheless the number 3 exists. This is because mathematical truths are necessary – for example, “2+1=3” is a necessary truth. So they would say that numbers are abstract, necessarily existing things. Again, these are exotic and strange examples. But that just underlines the fact that the things with which we have daily intercourse are physical, contingent things that have external causes. So when you look for examples of necessary beings, you are looking at rather unusual sorts of things.2
Question: Can you give some examples of why the universe can’t be necessarily existing?
Answer: We will talk about that later on. Hang on to that question.
Question: Sam Harris and Richard Dawkins like to bring up the question of “How do you explain where God came from?” Do you think they don’t understand this, or they are deliberately trying to fool the masses?
Answer: I am quite convinced that they don’t understand it. You have to grasp that a person can be a specialist with a profound knowledge of his narrow area of specialization and yet have a superficial grasp of things outside his area of expertise. I am sure these fellows have never even thought about the difference between necessary being and contingent being. Once you understand the idea of something that exists by a necessity of its own nature, the question of “Where did God come from?” or “What’s the cause of God?” becomes just a lame question. It becomes obviously misconceived. I think it is just that they are ignorant of these distinctions.
Question: I believe that is the point of God’s name being “I AM.” He is the only one that can say “I AM.”
Answer: Historically, that has been the Bible verse that theologians have used to connect with this idea of God as a necessary being. Thomas Aquinas would quote Exodus 3:14, “Tell them I AM that I AM.” “I AM has sent you.” This expresses God’s self-existent, necessary being. So you are absolutely right – that is the point of contact between the biblical tradition and this philosophical tradition.
Question: It seems to me that explaining God’s existence is far more difficult than proving his existence. The answer that something exists, namely God, simply because it has to – that seems a bit glib to me. What if God never created anything at all? Now how are you going to explain his existence? Also, this concept of propositions or mathematical objects existing independent of some other intelligence of some type, that seems way over the top to me. That means we are kind of surrounded by the number 4 just kind of out there.
Answer: I have sympathy with your view about the nature of numbers. That is the view I tend to as well. But I am just using this as an illustration to say that a good many people did and do think that numbers exist necessarily in this way. Even if there were no universe at all, as you say, if there were no realm of concrete objects, no matter, no energy, you would still have these necessarily existing mathematical truths and numbers and so forth. Similarly, with respect to God, I would appeal to your thought experiment actually in support of this. Even if there were no contingent objects, no physical objects, no space, no time, no matter, no energy, God would still exist by a necessity of his own nature. He simply exists because he is a logically necessary being whose non-existence is impossible.
Followup: How can you say God is logically necessary? Let’s say you had an atheist here asking, “How is he logically necessary?” There could be nothing. Didn’t Leibniz start with the idea “Why is there something rather than nothing?” There could be nothing – isn’t that a possibility? A logical possibility – not God, not anything?
Answer: Boy, these are deep questions that you are asking! Leibniz did start off with that question – why is there something rather than nothing? But the conclusion to which Leibniz was driven is that, in fact, it is impossible that nothing exists. There must be a necessary being. What is correct to say is that there is no strict, logical contradiction in saying nothing exists. You are not uttering an explicit contradiction. But when philosophers talk about necessity and possibility, they are not talking about what is called “strict logical necessity (or possibility),” they are talking about what is called “broadly logical necessity (or possibility).”3 Some examples might serve to bring this out. There is no explicit contradiction in talking about an unmarried bachelor, as there would be if you said he is a married, unmarried man – that would be explicitly contradictory. But nevertheless, there is no such thing as a married bachelor – that is broadly logically impossible. Or to give another example, the statement “The Prime Minister is a prime number” doesn’t involve a logical contradiction. There is no self-contradiction. But nevertheless, there is no possible world in which the Prime Minister is a prime number because prime numbers are not the sort of things that can be office holders in a political system. You can’t have a Prime Minister who is a prime number. So there are all kinds of necessary truths the negation of which is not a strict logical contradiction. So don’t be misled by thinking that because there is no strict logical contradiction in saying “Nothing exists,” that means it is really possible for nothing to exist. If this argument is right, in fact it is impossible in this broadly logical sense that there be nothing. There has to be something necessarily existing. I hadn’t planned on getting into this deeply, but when you ask questions, obviously, you begin to unearth a lot of these profound concepts.
Question: You always use the examples of married bachelors or Prime Ministers’ not being prime numbers, but I am curious if anyone has ever objected to that by saying, “A married man’s name is ‘Bachelor’” or “The Prime Minister is a member of a group called the Prime Numbers.” What do you say to people who object to this in such a ridiculous way?
Answer: What I would say is that they are not understanding the example. When you talk about a prime number, you are referring to numbers like 3, 5, 7 or 11, you are not talking about members of a club. Obviously, human beings belonging to a club called the Prime Numbers could be the prime minster. But that is just irrelevant, you are not dealing with the example.
Question: Since the concept of a necessary being is so hard to explain by way of examples, couldn’t it be easier to do so via a deductive argument? Such as saying that anything that exists through causality has to originally been caused by something that exists of its own nature otherwise nothing could exist?
Answer: Yes, I think that is fair. Your argument is saying that you look at things that have external causes and that, ultimately, you have to get back to a first, uncaused cause which simply exists by the necessity of its own nature and isn’t caused by anything else. You can deduce that. But what that will involve you in, though, is arguing against the possibility of an infinite regress of explanations. Why does the chain of explanations have to have an end? Why can’t it just go back and back and back and never have a final member? You would have to deal with that. Thus, I would prefer to do it this way, so as to avoid those types of infinite regress arguments. But if it helps you to grasp the idea of a being that exists by a necessity of its own nature, then, yes, this is a good way to think of it. It would be the being that terminates the series of contingent explanations and is the ultimate reality that explains why anything at all exists.
[Q&A: Just a comment about how an idealist redefines the word “exists” as meaning “being in the mind of God.” Dr. Craig just leaves this comment to the side]4
Question: [A long comment about how most people don’t think about the consequences of how it is we have the objects all around us.]
Answer: Fair enough! That is what we are trying to get folks to do – to think about “Why does anything at all exist?” – such as these things around us. I don’t think the difficulty here is grasping the idea of things that have external causes. That seems to me to be fairly easy to understand – a thing exists because it has a cause that produced it. If there is anything that is difficult to understand, it would be this idea of things that exist by the necessity of their own nature. And I am not sure what more to say about that than to give these examples that I’ve given and to say that this is a thing which is uncaused and which simply has a nature which is such that if this being is possible then it exists. It exists necessarily and cannot fail to exist. Notice in offering this premise 1, maybe there isn’t anything like that! We are not committing ourselves in saying that there is a necessary being yet. So the atheist can’t really object to it on that basis. Maybe everything that exists is what exists by an external cause. So in offering premise 1 in this expanded way, we are simply saying there are two ways of existing, necessarily or contingently, and everything that exists does so one way or the other. Really, that is all that is being said here.
Question: Hasn’t there been a history of denial of the category of “necessary” being applied to existence in philosophy?
Answer: Yes, although that seems to have been overtaken by now. Certain skeptics in the past, like David Hume, thought that whereas truths could be necessary (for example, “2+1=3” is necessary), they didn’t think that beings could be necessary. But these folks were ignoring this great Platonic tradition that says there are all kinds of things that exist necessarily. And I think in contemporary philosophy, you almost never hear anybody object to the idea of a thing’s being necessary in its existence. This would be a thing that exists in every possible world, and these old Hume-like skeptical doubts don’t seem to be voiced anymore. It does seem to be a coherent idea.
We’ve got to the point now that we understand premise 1 as saying that everything that exists is one of two types – either it exists contingently and has a cause that explains why it exists or it exists necessarily by its own nature. That is what premise 1 says.
A Defense For Premise (1)
Now the question is, what defense might be offered for premise 1? Why think that premise 1 is true? Let me share an illustration from the philosopher Richard Taylor that I find very persuasive in favor of thinking premise 1 is true. Taylor says, imagine you are walking through the woods on a hike and you come across a translucent ball lying on the forest floor. You would naturally wonder where that ball came from – what is the explanation of its existence? If your hiking buddy said to you, “Don’t worry about it – it just exists, inexplicably!,” you would think either that he was crazy or that he wanted you to keep on moving. But you wouldn’t take seriously the idea that this ball just exists without any explanation of its existence. Now suppose that the ball, instead of being the size of a basketball, were the size of an automobile.5 Merely increasing the size of the ball would not do anything to remove or satisfy the demand for an explanation of its existence, would it? Suppose it were the size of a house? Same problem! Suppose it were the size of a planet or a galaxy? Same problem! Suppose it were the size of the entire universe? Same problem! Merely increasing the size of the object does not do anything to remove or satisfy the demand for an explanation of its existence. And so I think it is very plausible to think that everything that exists has an explanation of why it exists.
Question: It seems like you can make that argument in the context of the forest where the ball seems out of place. When you get all the way to the universe, you are outside of the context of the ball seeming out of place.
Answer: That forms a nice segue to the next point that I am going to talk about. Let me try to address this question in that respect.
Objection: Universe Has No Explanation
Sometimes atheists will say, about premise 1, that this premise is true of everything in the universe but it is not true of the universe as a whole – which sounds kind of like this last question, where it is true of the ball in the forest but it is not true of the ball if it is the whole universe itself. Everything in the universe has an explanation of its existence but the universe itself just has no explanation of its existence.
This response commits what one contemporary philosopher has aptly called the “taxi cab fallacy.” This is based upon a remark by the 19th century atheist philosopher Arthur Schopenhauer. Schopenhauer pointed out that you cannot dismiss this principle enunciated in premise 1 like a hack when you have arrived at your desired destination. That would be arbitrary. You cannot say that everything has an explanation of its existence and then suddenly exempt the universe from this demand. That would be simply arbitrary. It would be arbitrary to say that the universe is an exception to premise 1.
Recall that Leibniz does not make God the exception to premise 1. So this isn’t special pleading for God. The premise on Leibniz’s view has universal applicability – it even applies to God! But it would be arbitrary for the atheist to say that the principle is true until you get to the universe and suddenly think you can dismiss it like a taxi cab because you have arrived at the universe. In fact, the illustration of the ball shows that merely increasing the size of the object until it becomes the size of the universe as a whole doesn’t do anything to remove the need for an explanation. That is, in effect, what the atheist is saying – that when the object is very, very big, then it doesn’t need an explanation.
Also notice how unscientific this response to the argument would be. Modern cosmology, which is the study of the large scale structure of the universe, is devoted precisely to an explanation of the existence of the universe. The whole project of cosmology is to explain why the universe exists. So that attitude toward premise 1 would actually cripple science – it would cripple the field of cosmology.
Trying to say that this applies to everything in the universe but not to the universe as a whole is simply arbitrary and unjustified. They would have to have some sort of justification for suddenly exempting the universe.
One way to think about it is this: this premise 1 is not a physical principle like the law of gravity or the laws of thermodynamics that operate in the universe; rather this is a metaphysical principle that applies to all things that exist – to being as being. Therefore, it simply supersedes or transcends any sort of distinction like “in the universe” or “of the universe as a whole.”6
Question: Shrink your example down to the very small world of atoms and quarks and things. The quantum mechanics field has been a playground for all sorts of strange and unproductive theological commentary. What are your comments on things coming in and out of existence like quarks and photons?
Answer: The argument would imply that merely shrinking the size of an object would not exempt it from needing an explanation of its existence either. I think that is quite correct. The closest you would have to something that looks unexplained would be these so-called virtual particles which can come out of the vacuum temporarily and then disappear back into the vacuum within a certain limit of time. But what you need to understand in this case is that the vacuum is not nothing – the vacuum is a sea of fluctuating energy endowed with a rich physical structure governed by physical laws. So it does constitute an explanation of these virtual particles. They are fluctuations of the energy within the vacuum. So it simply is not true that these things, if they exist, exist without any explanation of their existence. They do have an explanation for their existence.
Question: If we boil it all down, I believe that God always existed, and he is the Creator. Atheists may choose to believe that molecules and atoms always existed based strictly on nothing, but that is the side they choose to believe. There is no evidence to that fact. I cannot imagine an atheist wanting to argue about this if he doesn’t believe in God anyway.
Answer: Let me say this to answer the last part of your question. There are different kinds of atheists. There are the really hardcore types, and you are right – you can argue with them until you are blue in the face, and they wouldn’t be persuaded. But on the other hand, I meet lots of students whose atheism is very nominal or are struggling and searching. Or, for example, when I have spoken in the former Soviet Union or in China where they absorbed a kind of doctrinaire atheism from their Marxist propagandists, this atheism isn’t very deeply held or held with great conviction. In a case like that, an argument like this can dislodge them from their atheism. This view that there is a God who is the explanation of why everything exists really can make a difference in helping them to come to faith. So the Holy Spirit can use this.
To summarize, what I have basically argued is that premise (1) has a kind of self-evidence about it when you think about it, think about examples of things. And it is arbitrary to try to exempt the universe – that represents the taxi cab fallacy, of thinking you can just dismiss this metaphysical principle when you get to the universe. And, moreover, this would actually cripple science, because science seeks to find an explanation of the existence of the universe in modern cosmology. For those reasons, I think premise (1) is more plausibly true than false, and what the atheist would have to come up with is a justification for thinking the universe is an exception to premise (1).7
7 Total Running Time: 34:42