This is the weekly Q & A blog post by our Research Professor in Philosophy, Dr. William Lane Craig.
I have a couple of questions regarding the Leibnizian Cosmological Argument I am wondering if you could help me sift through. In your book reasonable faith you state, “Premise one is a modest version of the Principle of Sufficient Reason. It circumvents the typical objections to strong versions of that principle. For one merely requires any existing thing to have an explanation of its existence. This premise is compatible with there being brute facts about the world.” What are an example of some of these brute facts about the world that this premise would be compatible with? As Christians we hold the belief that nothing can exist apart from God. For a Christian how can we possibly hold this position? So how can premise one be compatible with there being brute facts? You go on to say, “What premise one preludes is that there could exist things which just exist inexplicably”. Isn’t saying something is a brute fact the same thing as saying something exists without any explanation? If I were to say the universe exists as just a brute fact, would this not be the same as saying the universe exists without any explanation? I feel a bit confused on this, if you could explain the difference between the two distinctions that would be great.
My second question relates to the universe existing by a necessity of its own nature. For the universe to exist by a necessity of its own nature, wouldn’t it have to be unchanging? For everything we see in the universe involves incessant change, at least on the molecular and atomic level. Would the fact that the universe is always changing give us good grounds for thinking the universe does not exist by a necessity of its own nature? I am just wondering if that would be a good argument against the necessary existence of the universe.
God bless you,
Dr. William Lane Craig’s Response
For the benefit of readers who are unfamiliar with G. W. Leibniz’s version of the cosmological argument, let’s lay out my formulation of the argument in Reasonable Faith, p. 106:
1. Anything 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.
3. The universe exists.
4. Therefore, the universe has an explanation of its existence. (from 1, 3)
5. Therefore, the explanation of the existence of the universe is God. (from 2, 4)
Your question, Austin, is about (1), which I call “a modest version of the Principle of Sufficient Reason” which “circumvents the typical objections to strong versions of that principle.” Leibniz’s own formulation of the Principle of Sufficient Reason in his treatise The Monadology was very strong: "no fact can be real or existent, no statement true, unless there be a sufficient reason why it is so and not otherwise." Notice that for Leibniz every fact, every true statement, must have an explanation. That entails that there are no brute facts, that is, facts without explanation. By contrast, as I explain in Reasonable Faith, my more modest formulation of the Principle “merely requires any existing thing to have an explanation of its existence. This premiss is compatible with there being brute facts about the world” (p. 107). My version of the Principle denies that there are beings which exist without any explanation. That’s all I need for the argument to go through.
You ask, “For a Christian how can we possibly hold this position?” You seem to think that if the weak version of the Principle is true, then the strong version is not true. That doesn’t follow. If you also believe the stronger claim that not only every being has an explanation of its existence but also that every fact has an explanation why it is so and not otherwise, that’s fine. You just don’t need to defend so strong a claim in order for the argument to succeed.
You ask, “What are an example of some of these brute facts about the world that this premise would be compatible with?” Well, typically they will be facts involving quantum indeterminacy. People who think that quantum indeterminacy is real and not just in your mind think that there is no explanation why, for example, a radioactive isotope decayed precisely at time t rather than earlier or later than t. As a causally indeterminate event, the isotope’s decaying at t has no explanation. So far as the cosmological argument is concerned, it makes no difference, and so there’s just no need to go down the rabbit trail arguing about this. What matters is whether the isotope itself has an explanation of its existence, which it certainly does.
Or consider statements about free choices of the will. There is no explanation of the fact that Jones freely chose to call his wife. For a free choice must be causally undetermined by factors outside the agent himself. But obviously Jones himself (not to mention his wife) does not exist without an explanation of his existence. Even if the fact that Jones freely called his wife has no explanation, there are no unexplained beings in this scenario.
More recondite examples are available (see my discussion in “The Cosmological Argument,” in Philosophy of Religion: Classic and Contemporary Issues, ed. P. Copan and C. Meister [Oxford: Blackwell, 2007], pp. 83-97). For example, what about the Big Contingent Conjunctive Fact (BCCF) comprised of all the contingent facts there are: p & q & r & s &. . . .? Does the BCCF have an explanation? The question is controversial. For if the explanation of the BCCF states a contingent fact, then it, too, must have a further explanation, which is impossible, since the BCCF includes all the contingent facts there are. But if the explanation states a necessary fact, then the fact explained by it must also be necessary, which is impossible, since the BCCF is contingent. Therefore, not every fact can have an explanation. There’s just no need for the defender of the Leibnizian cosmological argument to take a stand on this question. For what matters is that there are no beings that exist without an explanation of their existence, regardless of whether there is an explanation why the BCCF is true.
You respond, “Isn’t saying something is a brute fact the same thing as saying something exists without any explanation?” Not at all! As the above examples illustrate, there can be facts which have no explanation why they are so and not otherwise, even if everything that exists has an explanation of its existence. (Lest you say that facts exist, see my response in footnote 21 of the chapter in Reasonable Faith: “A fact may be taken to be a true proposition. As abstract objects independent of sentences, propositions exist necessarily, if they exist at all. What is contingent about them is their truth value (whether they are true or false). So the proposition exists by a necessity of its own nature, while its truth value may or may not have an explanation.”) So brute facts furnish no counterexample to my modest version of premiss (1).
You ask, “If I were to say the universe exists as just a brute fact, would this not be the same as saying the universe exists without any explanation?” Right, because then you would be saying that there’s no explanation why the universe exists. To say that premiss (1) is compatible with there being brute facts is not to say that it’s compatible with any or every fact’s being brute. Any fact asserting “x exists” will not be brute, if (1) is true.
So the key distinction to keep straight here is between things and facts. Things are beings that exist; facts are true propositions. A mea culpa: I would have been clearer had I called the Leibnizian argument “the argument from contingent beings” rather than “the argument from contingency.”
As to your second question, “For the universe to exist by a necessity of its own nature, wouldn’t it have to be unchanging?” I see no reason to think so. A necessarily existing being can have contingent properties. It could change with respect to those properties, while remaining unchanged in its existence. God, for example, can exist necessarily and yet exist in time, so as to change in knowing what time it is now. As for a good argument for why the universe is not a necessary being, look again at Reasonable Faith, pp.108-110.