Probably the most widespread argument for the existence of God today is the cosmological argument. (I discount the “Reformed epistemology” argument, which is not actually an argument that God exists but only that those who already believe in him should continue to do so.) According to the cosmological argument, we need explanations for everything, and then explanations for those explanations, which ultimately must come back to a First Explanation. In the more simplistic and less satisfying versions of this argument, the First Explanation is simply a first cause, a temporal beginning that sets the universe in motion. Such a first cause has little to do with the claims I’ve been making about value. But as I’ve noted a couple of times, the First Cause is hardly a proof of anything Godlike. After that first act of creation, the First Cause can just go home and ignore us and be ignored.

But things look rather different through if we view explanation more broadly, as Aristotle did. For among Aristotle’s four aitia, the so-called “four causes” that are really four explanations, is the “final” explanation: one explains a thing through its purpose, its telos, what it is for. And on the more sophisticated cosmological argument, not merely causes but purposes must go back to something: there must be a First Purpose of sorts, the telos of every other telos, an end to end all ends. The First Purpose, as opposed to the First Cause, is exactly an explanation of value; questions of “why should I do X?” will ultimately lead back to it. And if such an ultimate purpose exists, it takes the kind of guiding role in our lives that God would be expected to take.

C.S. Lewis’s moral argument for God’s existence claims that there is a basic universal human set of moral rules, and that this could not exist without a creator having put it there. I don’t think this argument works; differences in historically observed moral codes are far greater than Lewis takes them to be, and Lewis too readily conflates explanation at the level of value with the kind of causal explanation that evolution at least theoretically could provide. However, it seems to me that in his own confused way, Lewis is trying to get at something like the argument of the earlier weeks: to posit God as the explanation for real value. In that sense, it seems to me that Lewis’s argument, like the First Cause argument, turns out to be a confused version of the more sophisticated First Purpose argument.

Even Anselm’s ontological argument can be viewed in a somewhat similar light. Unlike the First Purpose and moral arguments, it is not exactly an attempt to explain the existence of value. But it does something parallel. It starts with an idea of value and goodness of a certain kind, observed by the mind, in the concept of a perfect being. This concept doesn’t make sense – so the argument goes – unless it exists in reality. The evaluative concept of a highest perfection, here, cannot be understood unless it turns out to really exist.

Whether the argument from design also follows a similar line of reasoning is more debatable. In a sense it works by conflating cause and purpose – by examining the purposes apparent in living beings and assuming those must be caused by an intelligent designer. But then it doesn’t really matter, because that is the one argument that – notwithstanding the arguments of intelligent design proponents – has been decisively refuted by empirical evidence. With the idea of evolution to explain the complexity of life on earth, we do not need an idea of God; of course there are gaps in evolutionary theory, as there are in any scientific theory, but they are much smaller than the gaps in any theory of divine design. Before Darwin, the design argument was by far the most compelling argument for God’s existence; now it is the least, and not because the others have gotten any stronger.

I tie together the proofs of God in this way because I want to get at the heart of the God question in philosophy – and I think that question ultimately comes down to the problem of bad and the problem of good. It is not that I necessarily buy any of the arguments discussed here, even the more sophisticated ones. The problem of suffering is too intractable – it’s at least as big a problem for those who believe in God as the problem of value is for those who don’t. But perhaps there is some sort of dialectical synthesis to be found in between?

Then, the HMS Beagle made its famous voyage to the Galàpagos Islands, where Darwin observed his famous finches. A huge variety of birds, each on different islands and looking dramatically different, each well suited to the conditions of its own island – but they all turned out biologically to be finches, closely related to each other and to the finches of distant South America. It seemed needlessly complex to suggest that God would create so many different birds in so many different places and yet make them all part of the same family. A more straightforward hypothesis was that the different finches had evolved from a common ancestor, by natural selection. God was no longer needed as a scientific hypothesis – and hasn’t been needed since.

In retrospect, the point that God was once a legitimate hypothesis seems obvious to me now. But when I encountered it, it came to me as something of a surprise, because I’m so used to living in a world where any attempt to find empirical evidence for God’s existence looks like a desperate grasping at straws. The worst of these is the “First Cause” version of the cosmological argument for God’s existence, that you need to have something setting the world in motion. Even if that argument works, it proves nothing like the existence of any God that has been ever worshipped. A mere First Cause is no more significant than any other cause. If God is a mere Divine Watchmaker who sets things in motion and then goes away and is no longer involved – as this hypothesis would suggest – then the universe with him is hardly different from the universe without him. This is not a God that matters.

Rather, nowadays, if you’re going to get rationally to anything like the traditional Abrahamic God, you need to keep science at arm’s length. This is one of the beauties of Anselm’s argument – it has nothing whatsoever to do with empirical evidence, it is 100% a priori, and therefore natural science simply can’t touch it. If it is wrong, its wrongness can and must be demonstrated without reference to natural science. The same seems to be true for ibn Rushd’s First Explanation cosmological argument when properly understood, though not for First Cause arguments in the usual sense. For here the question is not “what caused everything?” but “how can there be causation in the first place?” It is an explanation going much deeper. Unlike Anselm, it doesn’t necessarily get you to an omnipotent or omnibenevolent God; but it does seem to get you to something like the brahman of Śaṅkara’s or Rāmānuja’s Vedānta, a cosmic principle underlying everything, and such a principle does a lot to change the way we see the rest of the universe.

To me it’s been clear for a long time that any attempt to find God must go a priori, must not try to look in the empirical world. But looking back on Darwin’s story, it’s easier for me to realize that many people don’t see it that way. And that helps me understand contemporary views that have always struck me as a little curious. Not just the intelligent design movement, but the arch-materialistic atheists of contemporary analytic philosophy, like Paul and Patricia Churchland, who look at neuroscience and conclude that consciousness and free will don’t exist. They actually think that consciousness and free will are empirical hypotheses whose existence can be refuted with empirical evidence. Once upon a time, they, like God, might even have been exactly that.

MacIntyre notes that aitia, the Greek word usually translated simply as “cause,” also means “explanation” – as does its Arabic equivalent, illat. And Aristotle and ibn Rushd identify an aitia or illat as “that which explains, that which makes intelligible.” All of which suggests (MacIntyre doesn’t go quite this far) that we should render these phenomena as the “four explanations,” not the “four causes.” Then suddenly it makes sense that only one of these four (the efficient cause, the agency that brought a thing about) sounds like a cause to us – it’s the only one that is a cause in the way we understand the term. An “efficient cause” is just a cause; then there are formal, material and final explanations.

So to explain something means to be able to answer four questions about it: its form (what it is), its matter (what it’s made of), its cause (in a conventional sense), and its purpose (what it’s for). I don’t know if I think that these questions are exhaustive of explanation, but it seems reasonable enough to propose them as the questions one must ask of a thing in order to understand it. Understood this way, Aristotle now makes a lot more sense to me.

But perhaps more importantly, with this reading, I gain a new respect for the “First Cause” argument for God’s existence – with God now being understood as the First Explanation, not the First Cause. Rather, when we offer explanations of anything, those explanations in turn need explaining. Suppose we’re trying to explain a table in front of us. We ask:
What is it? It’s a table – but then what’s a table?
What is it made of? Wood – but then what is wood made of?
What produced it? A factory – but then what produced the factory?
What’s it for? Putting stuff on top of it – but then what’s the purpose of putting stuff on top of it?

Each such “but then” question can be answered, but the answer leads to a further question. Does this series of questions ever end? Aristotle and ibn Rushd, according to MacIntyre, consider the possibility that the series is simply infinite, that the explanations never stop. But if that’s the case, if there is an infinite chain of explanations, the infinite chain itself still needs to be explained. And explaining the series “can terminate only with a being, not itself a member of the series, which makes it the case that this particular series exists.” (MacIntyre, p. 53) That being must be a necessary being, not contingent or dependent on anything else; it must also be unchanging, and therefore immaterial. This much comes from Aristotle; ibn Rushd then identifies the being with the Abrahamic, monotheistic God.

Does this argument work? I’m skeptical, at the least. But here’s the reason I’m excited by all this: as with Anselm’s God, if this God exists, he (or she?) matters. He’s no longer just an empty First Cause, an ethically neutral Divine Watchmaker that creates the world and then wanders off to have a beer. He’s also the first formal and material explanation – so that in more than one sense, everything ultimately is God. More than that, he’s the first final explanation – so that God is the purpose of everything too. I doubt that all this is true. But if it were true, it would really matter – and that makes it worth investigating.

This is a simplified version of Anselm’s argument for the existence of God, often called the “ontological” argument. I’m not sure whether it really works; I’m inclined to say it doesn’t, although it’s hard to say where the logic goes wrong, especially in the more sophisticated version presented by Anselm himself.

Nevertheless, I consider it the best and most important of the proofs of God’s existence, even if it doesn’t work. Why? Because the God that it’s proving is actually God. A “greatest possible being” actually is likely to be omnipotent and omnibenevolent, a being that watches over us, intervenes in our affairs, and can tell us how we should and shouldn’t live our lives.

By contrast, most arguments for God’s existence are some variant on “cosmological” or “design” arguments – claiming only that the universe must be created by some intelligent entity or, more sparsely yet, some first cause that caused everything else to happen. But so what? If these arguments work, they don’t really matter all that much. The so-called God that they prove could just be some big thing that puts everything in motion and then goes away and ignores us, a “Divine Watchmaker.” And I don’t see that that makes any significant difference to our lives now. For that matter, they say nothing about the being’s goodness: Iris Murdoch quips that “a demon could have created the world.”

If Anselm’s argument works, it changes everything; if the cosmological or design arguments work, they change nothing, or almost nothing. Anselm’s argument doesn’t prove that God must have the historically specific qualities attributed to Him in any given tradition (such as becoming human in the person of Jesus); the God it proves could certainly be that worshipped by Jews, Muslims or Baha’is. But whichever tradition we associate Him with, this God is going to turn out a being that’s the best we can imagine – the most just, the most kind, the most powerful – and that’s the God whose existence, or lack of existence, actually matters.

EDIT: the last sentence of the first paragraph originally said “in thought as well as in reality,” which doesn’t quite get the sense of the point I was trying to convey.