Excursus on Natural Theology (Part 5): Argument from Contingency
March 17, 2023Argument from Contingency
It may seem strange to have begun an excursus on natural theology by arguing that we don’t really need arguments for the existence of God in order to believe rationally and even know that God exists. But we’ve seen that, in fact, arguments for God’s existence are not necessary because God can be known to exist in a properly basic way through the self-authenticating witness of the Holy Spirit.
But to say that arguments for God’s existence are not necessary in order to know that God exists is not to say that there are not also arguments that are sufficient for the knowledge of God. In fact, I would agree with Alvin Plantinga that even though belief in God is properly basic, still there are arguments that are sufficient to warrant belief in the existence of God.
Today we want to begin to look at some of these arguments for God’s existence. The first argument is the argument from contingency. Sometimes this is called the Leibnizian cosmological argument. I discuss this argument in my book On Guard and also in a deeper way in my book Reasonable Faith. We’ll be looking this morning at the version as it is laid out in On Guard.
I have always been impressed by the mystery of the existence of the universe. I remember as a boy looking up at the stars at night and wondering: where did all of this come from? It just seemed to me that there had to be an explanation for why all of this exists. Little did I realize that my boyhood question as well as its answer had been reflected upon by philosophers for centuries, even millennia. For example, Gottfried Wilhelm Leibniz (who was a polymath of tremendous genius of 18th century Europe, the co-discoverer of the calculus) stated that, in his words, “The first question which should rightly be asked is, ‘Why is there something rather than nothing?’” That is to say, why does anything at all exist? Leibniz believed that this is the most basic question that anyone can ask.
I must say, I agree with Leibniz on this score– logically this is the very first question which ought to be asked. Before we ask, “Why did the universe begin to exist?” or “Why is the universe fine-tuned for our existence?,” the most fundamental question is “Why is there anything at all?” This is clearly the beginning point.
Two centuries after Leibniz, Martin Heidegger, who was a very famous German 20th century metaphysician, wrote this: “Why are there beings rather than nothing? That is the question. Clearly it is no ordinary question. ‘Why are there beings, why is there anything at all, rather than nothing?’ – obviously this is the first of all questions.” That is where we will begin our survey of arguments for God’s existence with this most fundamental question of all: why does anything at all exist?
Leibniz came to the conclusion that the answer is to be found not in the universe of created things but rather in a transcendent cause of the universe, in God. God, he said, exists necessarily and is the explanation for why anything else exists.
We can put Leibniz’s argument in the form of a very simple series of premises which are on your outline.
1. Every existing thing has an explanation of its existence, either in the necessity of its own nature or in an external cause.
2. If the universe has an explanation of its existence, that explanation is God.
3. The universe is an existing thing.
4. Therefore, the explanation of the existence of the universe is God.
This is a logically airtight argument. That is to say, if the three premises are true, then the conclusion follows necessarily. It doesn’t matter if you don’t like the conclusion. It doesn’t matter if you have other objections to God’s existence. If you think that those premises are true, then you’ve got to accept the truth of the conclusion as well. Anyone who wants to reject the conclusion has got to say that at least one of those three premises is false.
But which one will he reject? Clearly, premise (3) is undeniable for any sincere seeker after truth. Obviously the universe exists! Therefore, the skeptic is going to have to deny either premise (1) or premise (2). So the whole question with regard to this argument comes down to this: are these two premises more plausible than not? Are they more plausibly true or are they more plausibly false? Well, let’s look at each one of them in turn.
Premise (1)
First, every existing thing has an explanation of its existence, either in the necessity of its own nature or in an external cause. You will notice that Leibniz makes a distinction here between two types of being. The first type is things that exist by a necessity of their own nature (a necessary being). This is the idea of a being which cannot fail to exist. It is something the non-existence of which is impossible. What would be an example of a necessary being? Very many mathematicians think that mathematical entities are necessary in this way – things like numbers, sets, propositions, things of that sort. Even those who are anti-realists – who don’t think that mathematical objects really exist – nevertheless recognize that if they do exist, then they exist necessarily. If the number 1 exists in any possible world, then it exists in every possible world. It would be impossible for the number 1, for example, to just contingently exist – to exist in this world but not in some other possible world. Even those who don’t believe in the existence of mathematical entities like numbers, sets, and geometrical figures still recognize that if they exist at all, they exist necessarily. These kinds of things are not caused to exist by something else. They simply exist by a necessity of their own nature, and it is impossible for them to fail to exist.
The other type of thing would be things that exist contingently. That is to say, they are contingent beings. Contingent beings are things that exist, but don’t have to exist. It is possible for them to fail to exist. They exist but their existence isn’t necessary; they could have failed to exist. This is the case with the world of objects around us – things like people, chairs, planets, galaxies, and so forth. These things exist, but they are not necessary in their being. We can imagine a possible world in which any or all of those things fail to exist. These kinds of things, if they exist, have explanations outside of themselves for why they exist. They don’t exist by a necessity of their own nature. If, for example, a unicorn exists in this world, there must be some explanation for why it exists rather than not exist. There are lots of possible worlds in which there are no unicorns. If a unicorn does exist, there needs to be some sort of explanation apart from the nature of a unicorn that would explain why the unicorn actually exists rather than is a mere possibility.
So when Leibniz says that everything that exists has an explanation of its existence, that explanation could be one of two sorts. The explanation could be that it exists by a necessity of its own nature. Or the explanation could be that it has a cause outside of itself that produces it in being. If God exists, God is a being that would exist by a necessity of his own nature. It is impossible for God to be caused by anything else. If God were to be caused by something else, then there would be something greater than God and therefore God wouldn’t be God. So by the very concept of God, God cannot be something that would be caused to exist by something else. If there is a God, then, he would exist necessarily. Leibniz’s argument is driving us toward a very powerful concept of God, namely, the idea of a metaphysically necessary being – a being that exists by a necessity of its own nature--not merely a contingent being that happens to exist, but a necessarily existing being.
What reason might be offered for thinking that premise (1) is true? I think when you reflect on it, there is a kind of obviousness about the premise. If something exists contingently – say, if there is a unicorn rather than no unicorn –, then there needs to be some sort of explanation for why one of those alternatives is actualized rather than the other. Why does the unicorn actually exist rather than not when its non-existence is possible?
Richard Taylor, who was a prominent 20th century American philosopher, gives a wonderful illustration for this. He says, imagine you are walking through the woods and you suddenly come upon a translucent ball lying on the forest floor. You would naturally wonder why it exists. How did it come to be there? If your hiking buddy said to you, “Forget about it! It just exists inexplicably! There is no explanation of its existence,” Taylor says you wouldn’t accept that. You’d think that the guy was either joking or just wanted you to keep moving. But it is obvious that there would be some kind of an explanation for why that ball exists.
Notice that merely increasing the size of the ball, say, until it is the size of an automobile, does nothing to explain its existence. Or making it even bigger to the size of a house. Same problem. Suppose it is the size of a planet. Same problem. Suppose it is the size of a galaxy. Same problem. Suppose it is the size of the entire universe. Same problem. Merely increasing the size of the object does nothing to provide or remove the need for an explanation for its existence.
If you have the sense that finding a ball in the woods requires an explanation for its existence, that, I think, will lead inevitably to saying that bigger and bigger objects (even the universe itself) will have to have an explanation of its existence because merely increasing the size of the ball does nothing to either provide or remove the need for an explanation of its existence.
With that we will close today. I will take up next time some atheist responses to premise (1) to try to exempt the universe from this principle.