I started working on an examination of Feser's book, and dropped the ball after chapter 2. I've been feeling guilty about that, so I'm now getting back to the project.
Chapter 3 opens very strangely, with a story about St. Thomas Aquinas putting an uppity nun in her place. I suppose it shouldn't surprise me; of course one of Feser's goals is to support the patriarchal order. After effusive praise of Aquinas, which left a bad taste in my mouth given the way it started, Feser spends several pages talking about how pathetically the New Atheists have misinterpreted Aquinas.
It takes him an astonishingly long time to get from ranting about how horrible the misinterpretations are to actually mentioning what he thinks they get wrong. Eventually, he points out that Aquinas intended to give a priori arguments (for the existence of God and various other things), and that many of the criticisms given by the New Atheists seemed to be treating them as empirical. Naturally, he ignores the (extremely likely) possibility that the New Atheists in question, mostly good followers of Hume, think no argument for the existence of anything can be a priori, and so are attempting to be as charitable as possible by interpreting Aquinas in a way that isn't automatically doomed. But if they have ignored the a priori features of the argument, I will not.
Still, before actually explaining how he thinks the arguments work, Feser digresses to spend some time describing his view of God. He says that he follows Aquinas in believing that the properties we attribute to God should be understood "analogically." To take one of the big examples, God is not literally a person "in the sense of being one individual thing among others who reasons, chooses, has moral obligations, etc." But God is somehow close enough to being a person for that to be the best way to describe Him. This notion of "analogical" properties seems to have the potential for endless abuse, and that potentiality, at least, is actualized in Feser; he freely uses the "analogical" nature of the properties to deflect problems, while dropping it when he wants to make specific claims derived from the alleged properties of God. The primary use of "analogical" properties in chapter 3 is to deal with one of the questions everybody has when reaching the end of one of Aquinas' "five ways" of proving the existence of God; even if the proof shows that something exists, why think that's God? The "analogical" properties enable Feser to be sufficiently vague about the properties of God to make drawing that connection much easier.
So, Feser's arguments for God:
1 (attributed to St. Augustine). There must be forms, and in some cases they can't exist solely in material things, nor could they exist solely in human minds. But Plato's proposal that they exist in a separate realm also doesn't work. So they must exist in an eternal and infinite mind. Given that God has only an "analogical" mind, I'm not sure that this is actually different from Plato's proposal. It's not surprising that someone with a neo-Platonist background would have proposed this. This argument also obviously depends on the success of the arguments against nominalism and conceptualism. Some of those were discussed in the previous chapter (and as I indicated in my examination of that chapter, I was not impressed), while some are discussed later in the book and will be examined as they come up.
2. (attributed to Aquinas). The unmoved mover, or perhaps better the unchanged changer. Feser says that Aquinas would grant that an infinite sequence of causes is possible if the causes are what he calls "accidentally ordered." According to Feser, Aquinas is instead arguing from the impossibility of an infinite "essentially ordered" series. In an essentially ordered series, each member depends on a previous member for its continued existence. This requires that each member of the series be simultaneous. I'm not sure that making it simultaneous makes the infinite series any more impossible, but perhaps more importantly it is far from clear to me that there's any reason to suppose there are such things. His examples of essential ordering involve chains of causes that extend through space, so if they truly are simultaneous, they would appear to violate relativity.
He could answer that relativity is only a scientific theory, and he's doing metaphysics, and he does after all largely dismiss evolution, but I doubt he would want to dismiss relativity as cavalierly. I think it's more likely that he'd say the examples are only for sake of illustration; the real simultaneous causes are also all in the same places, and so no violation of relativity. But if so, he needs to work a lot harder to prove that there are such simultaneous causes; he can't just say it's obvious. And if I'm wrong and he would instead prefer to reject relativity, then I can only say I find that line unpromising.
In the discussion of this argument, Feser also begins to address the traditional question of why we should think the unmoved mover is anything like the traditional conception of God. It has to be the special kind of thing which wouldn't require further explanation. And it seems that for Feser, and plausibly for Aquinas, the explanations which stop such regresses, which require no further explanation, are logical/metaphysical ones. So, in essence, this depends on something like the conception of God mentioned in the previous argument; God imposes the logical/metaphysical order. Perhaps God is the logical/metaphysical order? Probably not; Feser isn't that much of a neo-Platonist. But the unmoved mover has to be the mind (well, the "analogical" mind) that contains the forms, the one we encountered in the previous argument. So if that's God (big if!), the unmoved mover argument does get us to God.
In any event, Feser roundly mocks his New Atheist opponents for being so thick as to think God could require some further explanation. I've already mentioned what I think is really going on; to reiterate; I suspect that none of them think logic can move anything (for the very good reason that it can't), so they try to interpret Aquinas as proposing a prime mover that would actually be capable of moving things. But the sorts of things which actually can move other things do invite further regress. Feser seems to argue that his foes are morons because they reject arguments as obviously flawed when they would work fine if further metaphysical principles, which also seem obviously flawed to them, were accepted. I admit that this doesn't look as foolish to me as it does to Feser.
3. (Also Aquinas). The first cause. Feser again condemns his opponents for failing to see that the argument is that ordinary things must be caused, while God is a special kind of thing. And, again, it all comes down to the idea that ultimate explanation must trace back to logic/metaphysics. It is part of God's essence to exist, while the existence of other things does not come from their essence, but must be explained by their being caused by further things. Again, I'm sure his New Atheist opponents think it makes sense to ask what caused God because they reject Feser's theories about essences; if there are such things as essences at all, they are not the sort of things that could cause something to exist. Since they assume pure logic can't account for God's existence, the New Atheists think some other explanation is needed, and point out that it's no easier to find a non-logical explanation of God's existence than an explanation for the universe existing without God. And they are, of course, right. Further, given what murky and mysterious things essences are, the New Atheists wonder how it is supposed to be so obvious that if there are any such things, there couldn't be some which aren't god-like but which suffice to explain the universe. Again, as with the previous argument, Feser will say that since what's needed is a logical/metaphysical explanation, this requires the forms in the supreme mind (analogical mind, remember!)
For what it's worth, according to the modal theories of David Lewis, the universe necessarily exists. So that theory gives us the kind of logical/metaphysical explanation of everything Feser wants, without God. I'm sure Feser rejects the Lewis metaphysics, but I have to say that I find them more plausible than Feser's.
4. (Also Aquinas). The argument from design. I reconstruct Feser's version in this way: there must be non-Humean laws of nature to explain the regularities we observe, and the only way there could be such laws of nature is if there were a divine mind legislating them (again, we go back to the first argument, the idea that the forms, this time those which give things their causal properties, must be in at least an "analogical" mind). Of course I reject the need for non-Humean laws of nature, and I remain unconvinced that Feser would really have found God even if I had to grant this infinite and eternal "analogical" mind. But here I think Feser is especially unfair to his New Atheist opponents. As usual, he mocks them for asking for an explanation for God, but here I think it is unusually clear that they are being quite reasonable given their assumptions, and Feser needs a lot more argument and less mockery to displace those assumptions.
Feser explicitly draws an analogy between the way human intentions can lay out plans for something that hasn't actually happened and how God's mind is supposed to plan out the universe. Now, we actually know quite a bit about human minds, and the way human minds produce design and order is itself a process that involves the operation of the laws of nature. In asking for an account of God, the New Atheists are asking for something that can be found for the examples of minds we're familiar with. Now, it's true that Feser's God is supposed to be the source of the laws of nature, existing outside them, but there is a serious cost to trying to deflect the New Atheist demands by appealing to that. Feser says that it's obvious that minds are the sort of things that can impose order because we know of minds that do that, but the minds we know of that do that are the law of nature obeying minds. It is not particularly clear what it means for something to be a mind that does not obey the laws of nature; certainly we've never encountered such a thing. And if the laws of nature are a kind of order which could, of course, not themselves be produced by laws of nature, to conclude that they must be produced by a mind, when in every other respect the explanation of their existence must be totally different from any of our normal explanations (since our normal explanations always use the laws of nature, and so couldn't explain them), is an incredibly huge jump. Sure, it's only an "analogical" mind, but again Feser only seems to bring up the "analogical" feature when he has trouble. If he were really serious about it (like Hume's character Philo in the Dialogues Concerning Natural Religion), it would be harder to find fault with his position, but of course his view would also have few, if any, consequences.
Ultimately, Feser is correct that the arguments for the existence of God he gives depend heavily on his Aristotelian/Thomistic metaphysics, and fail horribly without those background assumptions. Conversely, if the Aristotelian/Thomistic metaphysical principles are granted, the arguments have considerable force, though I'm still inclined to doubt that what they establish is a particularly Christian God. However, Feser's metaphysics are widely rejected, for an assortment of reasons, some of them quite good. Some of them have been discussed already, and more will be if I get to the remaining chapters. I also don't think there's any excuse for the way Feser treats opponents who clearly think his metaphysical theories are false as if they were simply ignoring the obvious. I am most familiar with Dennett, and Feser's criticisms of Dennett on this score are quite egregious, insofar as Dennett's work contains extensive development of theories of mind incompatible with the Thomistic account. Dennett doesn't think Feser's story of forms in the supreme mind makes sense because he thinks he has overwhelming reason to believe minds don't work the way Feser's theory requires them to. Dennett could be wildly wrong about minds (he isn't, but that point is debatable), but given Dennett's theory of mind, it is as reasonable for him to dismiss the Thomistic arguments as it is for Feser, with his radically different theory of mind, to embrace them.
I remembered this, but I also tracked down the citation. The index of On the Plurality of Worlds is as wonderfully clear and informative as the rest of it, telling me that "nothing, possibility of" is discussed on pages 73-4, where, as I remembered, Lewis indicates that it is not possible for there to be nothing. He also denies that this is an explanation of why there is something, and I agree with him about that, but his standards of explanation would also rule out most of Feser's explanations. Lewis also notes that David Armstrong's very different modal theory has the same consequence. I believe Carnap's may as well, though I can't seem to find my copy of Meaning and Necessity, and I doubt the index of that would be as helpful anyway.