This is the weekly Q & A blog post by our Research Professor in Philosophy, Dr. William Lane Craig.
Dear Dr. Craig,
I have been arguing with a friend that is an atheist. I am also an atheist or perhaps more correctly, an agnostic about Leibniz’s cosmological argument. In our argument, I have been defending the version of Leibniz’s cosmological argument in On Guard:
(1) Everything that exists 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 (or, as I put it to him, an unembodied mind with many of the classical properties of God that could have the additional properties of God).
(3) The universe exists.
(4) Therefore, the universe has an explanation of its existence.
(5) Therefore, the explanation of the existence of the universe is God.
Two of his objections trouble me. Consequently, I have three questions about Leibniz’s cosmological argument for you.
First, is it true that there is no contradiction between nothing (despite it not being a thing, or the quantum vacuum) having the potential to create a universe and the universe coming into existence uncaused starting with nothing?
Second, does one commit the fallacy of composition by claiming that because everything we observe has an explanation of its existence (presumably why we have the metaphysical principle at work here), the universe probably has an explanation of its existence? It seemed to me reasonable to inductively reason that on the basis of everything we observe having an explanation for existing, the universe probably does. But my friend points out that when we use inductive reasoning, we take a sample of separate things in a category and make a claim about that category of things in general. We do not take a sample of separate parts of one thing (in this case the universe) and make a claim about that one thing. Since all observable things are part of the universe, my friend said I was doing the latter (I had to concede the point, but suggested that maybe it hinged on whether we treat the universe as a category of all things or a composite of them).
Third, since it seems Leibniz’s cosmological argument is still alive in the academy, are there any authors that write about Leibniz’s cosmological argument you recommend for further reading?
If after sufficient research, Leibniz’s argument proves more plausibly true than false, than on the basis of it and the abductive argument for the historicity of Christ's resurrection, I'm prepared to take Pascal's Wager.
Thank you for reading my letter.
Dr. William Lane Craig’s Response
Good for you, John! There’s great gain to be had by betting on God and little or nothing to lose. I’m glad that you and your friend have been discussing these things. I hope I can nudge you to the point of decision.
Your first question is confusingly formulated and needs some disambiguating. As I explained in my dialogue with Lawrence Krauss on “Why Is There Something rather than Nothing?,” the word “nothing,” properly speaking, doesn’t refer to anything at all but is synonymous to “not anything.” In this sense, the phrase “nothing has the potential to create a universe” means “there is not anything that has the potential to create a universe,” just as “nothing has the potential to exceed the speed of light” means “there is not anything that has the potential to exceed the speed of light.” In this proper sense, the theist will say that there certainly is something that has the potential to create a universe, namely, God. Therefore, it is false that nothing has the potential to create a universe.
This sense is different, I suspect, from your friend’s confused claim that “nothing has the potential to create a universe.” He doubtless takes “nothing” to refer to a state of nothingness or non-being. But even in that improper sense, the claim is clearly false, since a state of nothingness has no properties, no potentialities, at all, since there is not anything to possess them.
Now your question is, is there a contradiction between the (false) claim “nothing has the potential to create a universe” and the (equally false) claim “the universe came into existence uncaused starting with nothing (i.e., not starting from anything)”? I can’t see any sort of contradiction or inconsistency between these two statements, properly understood. The first claim denies there is anything with the potential to create the universe; the second claim holds that the universe did not come from anything but rather came into being uncaused. So these claims seem perfectly compatible: the second claim is that the universe is uncreated, and the first claim is that there isn’t anything that even could create the universe. The first statement is just somewhat stronger than the second: the second asserts that the universe is uncreated while the first says that the universe cannot be created.
What I can’t see is any defeater here of the Leibnizian argument spelled out above. Your friend is merely asserting that the universe has no explanation of its existence. But, as Leibniz argued, there is just no reason to exempt the universe from premiss (1). (Recall “the taxicab fallacy”—arbitrarily dismissing the Principle of Sufficient Reason once one has arrived at one’s desired destination.)
As for your second question, you are absolutely correct to distinguish between arguing inductively and arguing by composition. These are very different modes of reasoning. One could argue inductively for the truth of premiss (1) on the grounds that the things we encounter in experience have explanations of their existence, without any reasoning at all about parts and wholes. The fact that the individual things we encounter are part of the universe is just irrelevant to the mode of reasoning employed.
The knock-out objection to your friend’s claim that (1) is the conclusion to reasoning by composition is the fact that (1) is a universal generalization. It states that, for any x, if x is an existent thing, then x has an explanation of its existence. It is not a statement about one thing and therefore cannot be the result of an inference from the parts of a thing to the whole thing.
In my case, I don’t arrive at the truth of (1) either inductively or via part-whole reasoning. Rather I think that premiss (1) is just an obvious metaphysical truth, once one thinks about it. If something exists by a necessity of its own nature, that explains why it exists, and if something exists contingently, then there must be some explanation outside it which explains why it exists rather than not.
The answer to your third question is a hearty “Yes!” I especially recommend the work of Alexander Pruss on this head, for example, his book The Principle of Sufficient Reason: A Reassessment (Cambridge: Cambridge University Press, 2006), or his long essay “The Leibnizian Cosmological Argument,” in The Blackwell Companion to Natural Theology, ed. Wm. L. Craig and J. P. Moreland (Oxford: Wiley-Blackwell, 2009).
I am excited about the prospect of your becoming a Christian!
This post and other resources are available on Dr. William Lane Craig's website: www.reasonablefaith.org
 Having said that, I’ll bet your friend is making the confused and contradictory claim that the universe came into existence uncaused and that nothingness caused the universe to come into being. That is, indeed, contradiction piled on confusion!