Thursday, September 6, 2012

Rebutting the Leibnizian Cosmological Argument for God Part 1

This is part 1 in my attack on the Leibnizian cosmological argument.
  1. Rebutting the Leibnizian Cosmological Argument for God Part 1
  2. Rebutting the Leibnizian Cosmological Argument for God Part 2
The Argument

In this article I’ll rebut the Leibnizian cosmological argument (LCA) for the existence of God. There are many forms of the LCA, but for starters I’ll refer to this one as used by one popularized by Christian apologist William Lane Craig. I’ll also taking a bit from Maverick Christian’s blog article on the Leibnizian cosmological argument which (among other things) tries to present more defensible versions of the LCA.

  1. Everything that exists has an explanation of its existence, either in the necessity of its own nature or an external cause.
  2. The universe exists.
  3. If the universe does have an explanation for its existence, that explanation is God.
  4. Therefore, the universe has an explanation of its existence (from 1 and 2).
  5. Therefore, the explanation for the existence of the universe is God (from 3 and 4).

The principle of sufficient reason (PSR) says that everything (of a certain class) has a reason/explanation. The PSR comes in many forms, but the version this version of the LCA uses is premise 1. Premise 1 is also the weakest part of the argument, and the one I’ll attack in my series on the LCA. My alternate hypothesis is this: the universe exists eternally, with no explanation and no external cause of its existence. Still, let’s briefly discuss the other premises.

Premise 2

Pretty obviously true; no sensible atheist would deny this. By “the universe” the LCA means all of physical reality. The universe clearly exists.

Premise 3

In another version of the LCA (and in my opinion a more defensible one), Maverick Christian has “If the universe does have an explanation for its existence, that explanation is a transcendent personal cause,” and let’s call that the “weak premise 3” and let “If the universe does have an explanation for its existence, that explanation is God” be the “strong premise 3.” The weakened version of premise 3 is just in case the atheist insists on not having God as an explanation. Some terminology intro:

What does it mean to exist by the necessity of its own nature? A thing’s existence being metaphysically necessary means it is impossible for it to not exist (whereas contingent things both could exist and could have failed to exist, e.g. my own existence is contingent) and thus metaphysically necessary things exist in all possible worlds (where a possible world is a complete description of the way reality is or could have been like; thus “all bachelors are unmarried” is true in all possible worlds whereas there are possible worlds with different physical laws than ours, hence science’s need for empirical investigation). Some philosophers and mathematicians think that abstract objects like numbers exist necessarily.
Some consider “it is not the case that torturing infants just for fun is morally right” is a metaphysically necessary truth. Why can’t the universe’s existence be necessary? To quote from the blog:
There doesn’t appear to be any physical part of physical reality that is metaphysically necessary (e.g. stars and planets are contingent and indeed at one point they failed to exist; there are also no molecules that couldn’t fail to exist) and with that in mind consider the following argument from subtraction. Is a universe with only a thousand physical things possible? It seems so. How about a hundred? Sure. How about ten? How about five, four, three, two, and one? How about none? It seems like there is some possible world where no physical reality at all exists. (Notably, if nothing existed at all, this would fit in with the PSR since if literally nothing exists then there isn’t anything to explain.)
Maverick Christian argues further for the non-necessary nature of the universe’s existence, but I think this is enough to render the necessary existence of physical objects implausible. Why think “If the universe does have an explanation for its existence, that explanation is a transcendent personal cause” is true? To quote:
If we go the explanatory route of some external cause of the universe, an external cause of all physical reality would have to be nonphysical, and there are only two sorts of things we know of that could fit requirement: abstract objects (like numbers) and unembodied minds (e.g. God, if he exists). But abstract objects can’t cause anything. So the only viable candidate for a nonphysical cause seems to be a personal cause.

Not only am I prepared to grant that the weak premise three is probably true, I’ll even endorse the strong version. Why? Premise 3 is most charitably understood as a material conditional. In philosophy and logic, a material conditional takes the form of “If p, then q” and it is equivalent to “It is not the case that p is true and q is false.” Thus what determines the truth of a material conditional is the truth of p and q as follows:

  p    q     If p, then q
TT T
TF F
FT T
FF T

In the second line of the table where p is true (T), and q is false (F), the material conditional is false; otherwise the material conditional is true. This might sound odd, but a true material conditional is often good enough for deductive arguments like this, because when p is true, then q is true as well (since q can’t be false when p is true). Notice also from the table above that whenever p is false, the “If p, then q” material conditional is true. So by believing p is false one is accepting the material conditional, and thus when “If the universe has an explanation of its existence, that explanation is God” is a material conditional, by believing “the universe has an explanation of its existence” to be false (I’ll argue the universe has no explanation, that it is eternal and uncaused), I would be accepting premise (3) as true. Another way to look at it is this: I think it’s very likely that if atheism is true, the universe has no explanation of its existence (if atheism is true, it seems most likely that the universe is eternal and uncaused), but “If atheism is true, then the universe has no explanation of its existence” is logically equivalent to “If the universe has an explanation of its existence, then God exists” which is pretty close to the neighborhood of the strong premise 3.

So we can reject the argument’s conclusion by denying the universe has an explanation of its existence (a strategy I’ll defend more later) and while that means we must accept premise 3 as true, that’s hardly a fatal problem for atheism. So let this be a lesson: just because an argument is unsound, doesn’t mean that every premise is false. I propose that the universe has no explanation of its existence; it’s not metaphysically necessary, but neither does it have any external cause. This entails accepting the third premise, but we still avoid the conclusion.

But can’t an atheist believe the universe has an explanation? An atheist could, but at his peril. The universe does not plausibly exist necessarily, and an external cause of all physical reality will have to be something nonphysical. Once you go there (a nonphysical entity/force causing the physical universe to exist) by my lights you’ve already admitted some kind of supernatural force creating the universe, whether it be a deity or something else entirely. This would be conceding far too much to the theist than is warranted.

What’s worse, the only nonphysical entities in the metaphysical literature are unembodied minds and abstract objects (like numbers), but abstract objects can’t cause anything, leaving a transcendent (nonphysical) personal cause as the only known viable explanation. Yes, one could say maybe there’s a better explanation nobody’s ever thought of, but conceding that the universe has an explanation of its existence and that the best known explanation is a transcendent personal cause is again conceding far too much than is warranted (not to mention, as Maverick Christian points out in his LCA article, bare possibility of a better unknown alternative isn’t enough to reject an explanation; we wouldn’t reject the big bang theory because maybe there’s a better theory nobody’s ever thought of). Indeed, that the universe has an explanation of its existence and that the best known explanation is a transcendent personal cause—and that a transcendent personal cause is the only known viable explanation—would unavoidably constitute at least some degree of evidential support for a creator deity. So if the goal is to prevent the LCA from being evidence for theism, conceding an external cause of the physical universe is a terrible way to go. The atheist should avoid this if there is a better atheistic alternative, and I think there is.

What we’ve got so far

Some ill-advised moves for the atheist are:

  1. Saying that the universe’s existence is metaphysically necessary.
  2. Conceding that the physical universe has an external cause of its existence.

The first option is implausible, and the second grants too much evidential merit to theism that we don’t need to give it. Theists offer a number of arguments for their claim that the universe has an explanation of its existence, and I’ll argue that the arguments fail to present a convincing case for the third premise in my next entry, Rebutting the Leibnizian Cosmological Argument for God Part 2.