As I explained in my last posts (one, two), I’m expecting good things from the upcoming dialogue between Sean Carroll and William Lane Craig. Here, I’ll look at a species of the cosmological argument for the existence of God known as the contingency argument.
Before all that: Sean has linked to my previous post about this debate. Just to be clear, I don’t think Sean needs much advice. I’m really using these posts as an excuse to discuss Carroll’s ideas. He knows the arguments, knows the cosmology, has a clear idea about what naturalism is and how to defend it, and is an excellent public speaker. Carroll’s arguments are interesting and relevant, and Craig’s response won’t be anything as basic as “here’s a Grammar 101 lesson on using terms of negation and indefinite pronouns.”
Long post ahead. The short story: Carroll needs to make clear his objection to the Craig’s version of the principle of sufficient reason. In particular, why think that the universe is an exception (perhaps the only exception) to the general trend that things exist for a reason?
Craig’s Version of the Argument
The cosmological argument for the existence of God has been defended through the ages by a who’s who of thinkers: Plato, Aristotle, Al-Kindi, Ibn Sina, Al-Ghazali, Maimonides, Aquinas, Scotus, Spinoza, Leibnitz, … Of course, it has also been critiqued, most famously by Hume and Kant. The debate continues. Craig’s version of the contingency argument goes like this.
- Everything that exists has an explanation of its existence (either in the necessity of its own nature or in an external cause).
- If the universe has an explanation of its existence, that explanation is God.
- The universe exists.
It follows from these premises that God exists (homework). Note that this argument has nothing to do with whether the universe has a beginning.
Some atheists (Lawrence Krauss in particular) object to the second premise, thinking that God is just crowbarred in, an ad hoc assumption. But premise 2 has its own argument:
4. Since the universe is the totality of space, time, matter and energy (i.e. that’s the sense of universe being used here), the cause of the universe must be spaceless, timeless, and immaterial.
5. The most plausible immaterial kind of thing that could cause a universe is a mind.
6. A spaceless, timeless, and immaterial mind that causes the universe deserves to be called God.
Premise 5, in turn, has its own argument based on the causal effeteness of abstract entities. If you want to go after premise 2, you need to deal with this argument. Krauss didn’t.
Getting slightly ahead of myself, Carroll seems to object to Premise 1. This premise is a version of the infamous Principle of Sufficient Reason (PSR). It is a mild version, applying only to things, not to all (contingent) truths. Craig argues for premise 1, or at least that the universe is not an exception to premise 1, as follows.
It would be arbitrary for the atheist to claim that the universe is the exception to the rule. Merely increasing the size of the object to be explained, even until it becomes the universe itself, does nothing to remove the need for some explanation of its existence.
Alexander Pruss has advanced arguments for a version of the PSR along these lines. (I’m paraphrasing, dangerously).
8. If the universe could exist without explanation, then it would be inexplicable why just anything couldn’t exist without explanation. In other words, why is only the universe an exception to premise 1?
9. Universal principles are simpler than principles that apply to an arbitrary subset. The simplest explanation of fact that contingent things typically have explanations is that all contingent things have explanations.
Let’s consider with what Carroll’s response might be, as gleaned from this reply to an op-ed piece by Paul Davies.
“[A]t first glance, it seems plausible that there could be [an] answer to the question of why the laws of physics take the form they do. But there isn’t. At least, there isn’t any as far as we know, and there’s certainly no reason why there must be. The more mundane “why” questions make sense because they refer to objects and processes that are embedded in larger systems of cause and effect. … The universe (in the sense of “the entire natural world,” not only the physical region observable to us) isn’t like that. It’s not embedded in a bigger structure; it’s all there is. We are lulled into asking “why” questions about the universe by sloppily extending the way we think about local phenomena to the whole shebang. What kind of answers could we possibly be expecting? … [The correct possibility seems to be] that’s just how things are. There is a chain of explanations concerning things that happen in the universe, which ultimately reaches to the fundamental laws of nature and stops. This is a simple hypothesis that fits all the data; until it stops being consistent with what we know about the universe, the burden of proof is on any alternative idea for why the laws take the form they do.”
Let’s break it down. Lurking in the background of this entire discussion is this question: what makes an explanation an ultimate explanation? What is it about this explanation that makes another iteration of “and why?” out-of-bounds? Carroll’s argument seems to be:
10. Chains of explanations have to end somewhere.
11. Once we arrive at a simple explanation that fits all the data, there is nothing to be gained by going any further. Such an explanation should be considered an ultimate “stopping-point” explanation.
12. The fundamental laws of nature are just such an explanation for the physical universe.
13. Thus, we should consider the fundamental laws of nature to be the ultimate explanation of the universe.
Carroll’s formula of “simplicity + fits the data” needs a closer look. (more…)