The portrait above is of the famous German philosopher Gottfried Wilhelm Leibniz (1646-1716). One of the most important intellectuals in the history of Western philosophy, Leibniz, like Plato and Aristotle, made major contributions to multiple areas of human inquiry, including math, science, history, and philosophy. Among his achievements was an argument for God's existence based on a philosophical concept called contingency.
In metaphysics (the field of philosophy concerned with concepts such as space and time, substances, first causes, and what it means "to be"), one of the most important questions is, "Why is there something, rather than nothing?" Just consider that for a moment. You are reading this blog post using some kind of physical device, such as a phone, tablet, or computer. You're sitting on something like a chair or couch. You are a physical being with a body, brain, and soul, which allow you to be aware of your surrounding and to read and comprehend these words. All of this is able to take place because you live on a planet with an atmosphere in which you can survive, in a solar system that allows Earth to exist and produce life, in a galaxy that...and so on and so forth. Why does any of this exist?
When we think of absolute nothingness, the lack of any existing thing, physical or not, it seems reasonable to think that there could have been a set of circumstances in which nothing existed. No space, no time, no physical things, literally nothing. If that's the case, then why does something exist? The very fact of existence seems to call for an explanation.
Many will confuse the problem of contingency with the argument from the beginning of the universe, which I covered last week. Because of this, they will think that the problem posed by Leibniz is actually a scientific problem. This is mistaken because what we're looking for is not necessarily a cause for the existence of the universe but an explanation. Let me try to give an example. Think about the number 7. Does the number 7 exist? This is actually hotly debated among metaphysicians and mathematicians, but let's assume for the sake of argument that the number 7 exists. If it did exist, what would explain its existence? It wouldn't exist as a physical object. Instead, if it exists, the number 7 would have a nonphysical sort of existence. Would the number 7 exist only in some circumstances but not others? Evidently not. It seems like it would be the sort of thing that'd exist in all circumstances, in the same way that, no matter what, 2 and 2 will always add up to 4. If that's the case, then the number 7, if it exists, exists because of a necessity of its own nature. It exists because it's part of its nature to exist.
In the same way, we could ask the same question of spacio-temporal reality. Physical objects, such as human beings, trees, dogs, planets, and stars, seem to be contingent in their existence. That is, they could exist in some set of circumstances but not in others. Think about the various things that took place in order for your parents to meet, and you will realize just how contingent your existence is. The number 7, on the other hand, exists necessarily, that is, as a result of some necessity in its nature. Well, if the universe is contingent, then what explains that contingency? It seems like some external cause brought the universe into being. Here, we have the basic skeleton of the argument from contingency.
Here is the video from Reasonable Faith about this argument:
For reference, here is the syllogism:
Everything that exists has an explanation for its existence, either in the necessity of its nature, or in an external cause.
If the universe has an explanation for its existence, the explanation is God.
The universe exists.
Therefore, the explanation of the universe's existence is God.
The logic of this argument is more complex than what we've learned so far, so bear with me. If you read my post on logic, you may recognize that we did not learn how to translate every premise of this argument, in particular premise 1. If you read my post on the argument from the beginning of the universe, you may recognize that this argument contains the same claims about the characteristics of every member of a class, which is called universal quantification. This argument, then, builds on what we've already learned.
We also need to learn a particular proposition called a disjunction. In common English, we call this an either/or statement. In symbolic form, "or" is represented with the letter "v." Using our standard p and q, this is how a disjunction is written symbolically: p v q.
With this in mind, we can see that premise 1 includes a disjunction, namely, in that anything that exists can be explained in either the necessity of its own nature or an external cause. But premise 1 is also a conditional statement because an object's needing to be explained is conditioned on its existence. Here, however, it gets a little odd. I have written and rewritten this section a few times trying to break this argument down in a couple of different ways, and it's been slightly frustrating. But I think that I've finally figured this out. If you read the first premise carefully, you might notice that it includes two propositions in one statement, rather than one. The first is that "Everything that exists has an explanation for its existence." The second goes on to explain what that explanation might be. I was trying to symbolize this premise as only one proposition, but what if I thought of it as two propositions and, in fact, as conditionals? Let's rewrite the first premise as two premises like this:
Everything that exists has an explanation for its existence.
Everything that has an explanation for its existence is explained by either the necessity of its own nature or an external cause.
This will help to clarify the structure of the second (now the third) premise. Anyway, how do we symbolize this? Remember that, because these premises claim something about all the members of a class, they will take the structure: "For any x, if px, then qx." Therefore, we can symbolize these premises by using E to mean "exists," P to mean "has an explanation for its existence," N to mean "the necessity of its own nature," and C to mean "external cause." Here are the premises:
(x) Ex->Px
(x) Px->Nxv Cx
For the third premise ("If the universe has an explanation for its existence, the explanation is God."), notice that the first half of the statement, or the antecedent, claims that the universe has an explanation. Using u for "the universe," we can see that the antecedent is just Pu. That is easy enough. What about the second half (the consequent)? This is an entirely new proposition, so we need a new letter for it. Let's call it G. How does G fit into all of this? Again, this took some thinking, but I think that the best way to understand this is to say that G entails that Cu. Here, again, perhaps the best thing to do is to split the premise into two premises. Let me list those:
If the universe has an explanation for its existence, then the explanation is an external cause.
If the explanation for the existence of the universe is an external cause, then the explanation is God.
Applying the symbols we already have, here are the symbolized premises:
Pu->Cu
Cu->G
Thank the Lord, premise 3 is easy! It's just Eu. Let's put the whole argument together now:
(x) Ex->Px
(x) Px->Nxv Cx
Pu->Cu
Cu->G
Eu
Therefore, G
Notice that, once the first proposition is granted, the argument moves like a straight line through every other premise by the rule of inference, modus ponens. Just to illustrate this more easily, let's look at another example, this time with p, q, and r.
p->q
q->r
p
Therefore, q
Therefore, r
Whew, we're finally done with the logic of this argument! I promise that this is as bad as it gets. Again, I encourage you to take notes if you want to retain this information and really dive deep into the logic of this argument.
With the logic of the argument laid out, we can see that, though a bit complex, the argument is valid. Now, let's move on the soundness of the argument. Again, the video does most of this for me, so I'll start by simply listing the support for each premise:
Premise 1: Everything that exists has an explanation for its existence, either in the necessity of its nature, or in an external cause.
This is called the principle of sufficient reason. It is one of the most important metaphysical principles, first espoused by Leibniz. The argument assumes this principle, more or less, but it is persuasive in that it is intuitive. It seems right to say that nothing that exists exists without some reason for its existence, whatever that reason is and even if we have a hard time discovering that reason.
Premise 2: If the universe has an explanation for its existence, the explanation is God.
This premise tends to take people by surprise. It seems to come out of nowhere, and people tend to think, "Why in the world would you think a thing like that?" In other words, it seems to just assume without reason that God is the explanation. The support for this premise, however, is quite powerful. Two arguments can be made for it:
When we reflect on the fact that the universe is a contingent thing, as opposed to a necessary thing, then we have to reflect on what type of being could be its cause. Once we analyze the nature of that cause, God seems like the only plausible candidate for a cause.
The premise is logically equivalent to the statement that "if God does not exist, then the universe has no explanation for its existence." Many very prominent atheists, such as the atheist philosopher Bertrand Russell, inadvertently agreed with the second premise by arguing that the universe's existence had no explanation. Thus, logically speaking, atheists agree with premise 2.
Premise 3: The universe exists.
Here we are.
Can any of these premises be denied cogently? Strangely enough, the first premise is by far the most controversial premise, since the principle of sufficient reason is still hotly debated today. That being said, this seems to me to be an example of the silliness of academics. I'm not sure if I just haven't read much of the debate, but I don't find much support for denying the principle of sufficient reason. Surely, there's more reason to support it than not.
The debate over the truth of the principle of sufficient reason seems, to me, to boil down to a debate about whether any so-called brute facts exist. A brute fact is an object for whom no explanation exists. It just exists. Remember that, above, we distinguished between an object that exists contingently and one that exists necessarily. The principle of sufficient reason essentially covers these two alternatives; for any object that exists, either that object could have failed to exist or must exist because of its nature. If one wants to object to the principle of sufficient reason, then, one must show that there exists some object for whom neither of these two alternatives could apply and (this is important) that we could know that about this object. This leads, in my mind, to three major problems with objecting to the principle.
First, if a brute fact does exist, then it would seem to undercut what seems like an intuitive (practically undeniable) metaphysical insight, that objects exist either contingently or necessarily. If we could know that an object is a brute fact, then it seems like we'd be at a complete loss as to whether its existence is merely possible or necessary, especially given the fact that, if we knew whether it were either, we'd then be able to determine its explanation. To me, this seems to make the very concept of a brute fact somewhat incoherent, since its very existence would remove the possibility of knowing much more at all about the object or the nature of its existence.
Second, it seems to me that to deny the principle of sufficient reason on the basis of the existence of brute facts is self-defeating. That is, the objection would actually affirm the principle simply by adding a third alternative. Why is that? If one were to ask, "Why does object x exist?" then the answer, "X is a brute fact," is an explanation! So it seems to me that to claim that brute facts exist is consistent with the principle of sufficient reason; therefore, it does not undermine it.
Third, if brute facts did exist, it doesn't seem to me like we could know it. The principle of sufficient reason seems to me to entail that all objects have an explanation for their existence, even if it is difficult at times to discover that explanation. This is why atheists find it hard to explain the existence of the universe; if God does not exist, then no other cause seems to suffice, so they instead deny the principle of sufficient reason. Mere lack of knowledge is not a reason to deny the principle, especially given that, if we think about what kind of object a brute fact might be, it seems like we would not be able to know much about the object in the first place. The problem here becomes unsustainable; the less we know about the object, the less certain we can be that it isn't explained by either an external cause or necessity. But, if the object is a brute fact, the less we'd know about the object! Because of this, even if brute facts exist, I am not sure that we could be certain enough that they exist in order to deny the principle of sufficient reason.
These three responses are my own reflection on the first premise; I will admit that I have not read much in this area and am not very familiar with the particulars of the debate about the principle of sufficient reason among philosophers. These responses, however, seem to me to be reasonable, and I'd be curious how philosophers who deny the first premise would respond to them.
I will be honest that I've not heard an argument against the second premise, and it seems absurd to deny the third premise, so I'll leave those alone.
I'll close this post with a couple of points about the strengths of the argument from contingency. When William Lane Craig wrote his book On Guard, which was a shorter work on apologetics for lay Christians, he was questioned for beginning his section on natural theology with the argument from contingency. The argument is infamous for being very abstract, given how metaphysical it is. Dr. Craig responded by arguing that it is good to start with the argument because it gets people thinking about the deep questions of life. When you sit back to reflect on the nature of existence, why something exists at all, you're invited to consider questions that take us to timeless themes such as existence, meaning, and purpose. As Dr. Craig recognizes, the argument from contingency is invaluable in getting us to think deeply about these all-important questions. I believe that that is one strength of the argument. Even if you find this material difficult to grasp, don't despair. Just ask yourself, "Have I ever really thought about how amazing it is that things exist?" At the end of the day, that's what Leibniz wanted us to reflect on.
I also think that the argument from contingency is an invaluable introduction to philosophical reflection and key philosophical concepts. In teaching the argument now for a couple of years, I've found it invaluable as a tool for helping students to begin thinking philosophically, and I've seen students get really excited about apologetics because of the argument from contingency. This is why I love the argument, because it reminds me of what I love about philosophy.
Finally, I'm convinced that this argument is good. It's primary strength, in my opinion, is that it is grounded in such intuitive premises. Unless you are in the ivory tower, the principle of sufficient reason will probably seem obviously true to you, once you grasp it. The second premise is agreed upon by theist and atheist alike, and the third premise is so obviously true that you'd be irrational to reject it! From such intuitive premises, we see that God exists. This is a particular strength of the argument.
Phew! We made it. That was a lot harder than I thought it would be. If you've made it this far, I commend and congratulate you. The argument from contingency is a beast, but it rewards those who stick with the challenge of understanding it. I hope that you found this argument both interesting and edifying. Next week, we'll discuss the argument from the fine-tuning of the universe. This is another fascinating argument based on recent scientific research. Tune in next week for that post!
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