God and Ultimate Explanation
What troubles the philosophical atheist most is any defense of an explanatory principle ranging over a sufficiently wide numbers of categories such that naturalism becomes incapable of providing a principled explanation ender. Cosmological arguments down the ages have advocated many such explanatory principles, claiming only classical theism can satisfy the hunt for ultimate intelligibility.
For example, theistic thinkers from Aristotle to Aquinas to Liebniz have suggested the following categories of reality are such they require an extrinsic principle for their existence and intelligibility: changing things, qualitatively finite things, composite things, contingent things, etc. Thus, for thinkers like them, one must ultimately transcend these categories to arrive at some truly fundamental explanation, which can explain everything in front of it but can itself be explained internally. In other words, it means arriving at some reality that is unchanging, qualitatively infinite, absolutely simple, and has a necessary nature (say, in virtue of having an essence that is identical to its existence). That is, arriving at some reality where if we could grasp its essence, we could “just see” its necessary existence and perfect freedom.
The strongest objection to cosmological arguments is the brute fact objection, which denies that reality is completely intelligible and that everything that crucially demands an explanation has one. In other words, something can exist, it can make sense to ask why it exists, and yet nothing accounts for it. As Bertrand Russel once said of the universe, “…it’s just there, and that’s all.”1
Of course, I have had much to say about the costs of proposing brute facts – for my money, the epistemological costs of denying PSR are most unbearable – but set that aside. For I believe it is correct that the majority (even if not all) versions of cosmological arguments run implicitly on PSR. Ultimately, I don’t see this as problematic, because PSR is necessarily true. However, if I were to press atheism as far as I could, I would push the brute fat – sorry, funny typo; I meant, brute fact – objection as far as I could.
But here is something else to consider. If one believes everything has an explanation (either from another or through itself), then theism should be extremely appealing, because it offers a category of reality that could serve as self-explanatory: in fact, the only one that possibly could. However, even if one doesn’t think everything requires an explanation, almost everyone thinks we should explain things as far as we can. Especially if the argument from the atheist is that atheism can explain as much as theism, if it can simply be shown theism has greater explanatory depth and/or range, then a major “point score” has occurred for the theist apart from embracing any full-throated PSR.
In the former approach, one must establish that God could serve as, really, a self-explanatory fact, and PSR. That God is such that his nature could eliminate brute facts entirely.
In the latter approach, one must establish that something which crucially demands an explanation (for example, all space-time reality, or the entire cause-effect system of nature, or whatever), which inevitably lacks one on naturalism, can be given a deeper explanation by theism. All the better if one can propose theism as a more unified and simpler explanation, as well, which I believe is the case. Thus, even on the “theoretical virtue” account, theism should be preferred.
My position is both should be maintained. Certainly, I believe brute facts must be driven to extinction to escape absurdism and that only Classical Theism is up to the task. However, I also believe that any naturalistic account – in virtue of having to posit some fundamental reality that excludes classical theism (i.e., pure actuality) – will always have features that crucially require deeper explanation but cannot possibly find one (because, for the naturalist, this is their fundamental reality.)
From his famous BBC debate with Fr. Coppleston, summarized and quoted at “A Debate between a Critic & a Believer,” Philosophy Dungeon (blog), at https://philosophydungeon.weebly.com.