The next Vox Apologia is on the cosmological argument for the existence of God, and I happen to have some ready-made notes on it from back when I taught a course that included it as a topic, so I've decided I might as well post them and submit it as an entry. These notes were last modified September 21, 2001, so they may not reflect my current thought. I'm not editing them at all. Also, I should say that my presentation depends heavily on William Rowe's work, most importantly the short article he wrote for introductory courses that appears in Reason and Responsibility, ed. Feinberg and Shafer-Landau, with one reference to the other text we used in that course, Jan Cover and Rudy Garns's Theories of Knowledge and Reality (abbreviated TKR).
It�s easy to get lost in the details of the cosmological argument. This handout focuses on the main structure of the argument while sorting through the details of each part.
The argument relies heavily on the Principle of Sufficient Reason (PSR), which requires and explanation for any actual thing or any fact. William Rowe�s criticism of the argument amounts to saying that we have no reason to believe PSR. I will save this discussion for the end. For now, let�s take it to be a reasonable principle (if for no other reason than to see what follows).
Given PSR, there are two kinds of beings -- dependent beings and self-existent beings. Dependent beings would be just about anything you come across in ordinary experience and lots more -- rocks, trees, houses, people, stars, electrons, etc. For something to be a self-existent being, its own nature has to provide the explanation for why it exists. God has traditionally been offered as a good candidate for a self-existent being, since traditional theology has always taken God to be necessary and self-existent.
The argument first shows that it cannot be that there are just dependent beings, even if they go infinitely back into the past. Samuel Clarke, G.W. Leibniz, and others who endorse this argument will be perfectly happy to concede that dependent beings have always existed, with no beginning, with each explained by earlier dependent beings. They can then still ask why there are any dependent beings at all. This infinite series into the past does not answer that question, which leaves us having to offer another solution -- there must be some being that is not dependent, and that being can provide the answer to the question why there are any dependent beings. If PSR is true, then this is in fact the only kind of answer that would do the trick.
Here is a valid argument that reflects this kind of reasoning:
(1) every being is either dependent or self-existent
(2) not every being can be a dependent being therefore, there is some self-existent being
If PSR is true, then (1) is true, because the only other possibility would be for a being to be without explanation, and PSR rules that out. Similarly, if PSR is true, (2) is true, since there is no way to explain why there are dependent beings by simply adding more dependent beings. Some other kind of being needs to exist, and the only other kind of being is a self-existent being. The conclusion logically follows (disjunctive syllogism -- see TKR 20).
Objection: a collection of dependent beings isn�t itself a dependent being
Response: but that doesn�t mean it doesn�t need explanation. Why is there such a collection? Why are there any dependent beings? If PSR is true, we still need an explanation for that.
David Hume�s Objection: explaining the parts is all you need to explain the whole
Response: Hume sees no difference between these two things:
explaining all the dependent beings by explaining each dep. being
explaining all the dep. beings by explaining why there are any
But there is a difference between those two kinds of explanation. Just doing the first doesn�t explain why there are any dependent beings.
Objection: Doesn�t Hume�s objection give us an account of why we might think that the Universe itself is self-existent? Then the conclusion of the argument is true, but it doesn�t give us anything like the traditional theistic God.
Response Part 1: Suppose that is right. This commits us to a certain view about the universe, namely that it is the sort of thing that couldn�t fail to exist. It means it is false to say that there might not have been a universe. This is certainly not a conclusive argument, but many philosophers want to avoid this conclusion.
Response Part 2: Suppose you are comfortable with that conclusion. Do we really have an explanation for why there are any dependent beings at all? Being self-existent simply because your parts are all explained still doesn�t give an explanation of why there are any such parts. The traditional conception of God explains it more fully. It's God�s nature to exist. God is the sort of thing that has to exist, but God is also viewed as a creator. Would we see the universe as a creator in the same way? It's hard to see how, which might leave us thinking that the universe as a whole doesn�t serve as the kind of explanation that God does.
William Rowe: What�s wrong with having just one brute fact -- something with
absolutely no explanation -- and what if that fact is just the existence of dependent beings? Then there�s no reason why any dependent beings exist. The question is meaningless (like the question of where the universe is or when the timeline is). This would mean that PSR is right about individual beings but not for the whole.
Theist: Don�t we sort of assume it all the time? It seems intuitively true.
Rowe: That doesn�t mean it�s right. We�re often wrong about principles that seem right.
Theist: But don�t claims that seem intuitively true deserve the benefit of the doubt unless we can come up with good reason to think they�re false?
Rowe: If it�s intuitively true, then why do many philosophers doubt it?
Theist: They don�t have any evidence to doubt it. They just claim that they don�t have any evidence for it.
Rowe: It�s called begging the question when you assume a premise that guarantees what you�re trying to prove, and there�s no reason to believe PSR, so the argument begs the question. Don�t assume anything that will guarantee what you want to prove.
Theist: Since it seems intuitive, and we rely on it all the time, why not assume that it�s true? That�s completely independent of the God issue, so it�s not begging the question. In fact, to dismiss a principle that seems intuitively true (and we also happen to rely on) without argument just because you want to resist the conclusion that God exists seems to be begging the question the other way. If you deny PSR because you don�t believe in God, isn�t that just as bad? So you are doing exactly what you accuse the theist of doing. You deny the principle to avoid theism, and the theist affirms the principle to prove theism.