332 thoughts on “Five Proofs”

1. keiths: The problem here is that you and KN are conflating two dichotomies: contingent/non-contingent and necessary/non-necessary.

   I don’t believe we are. non-contingent == necessary and non-necessary == contingent.

   contingent (i.e., non-necessary) / non-contingent (i.e., necessary) and necessary (i.e., non-contingent) / non-necessary (i.e., contingent)

   keiths: Necessary entities are those that must exist as a matter of sheer logic.

   It seems to me that you are confusing mental entities with ontological entities.

   For example, you appear to be arguing for the existence of any number of necessary beings. Yet the argument is that there is only one necessary being and can be only one necessary being.

2. walto,

   That all seems correct to me. It’s a terrible argument.

   Though you and I might have a philosophical disagreement about whether premises ought to be ‘obvious’ and what the ‘obviousness’ of a premise consists in.

   Quine once called logic ‘a theory of the obvious,’ if I recall correctly. I find that suggestive, but if so, the obviousness is of the inference, not of the premises.

   A few years ago I had the following worry about the nature of logical proofs. In a deductive argument, for it to be deductive, there can’t be any more information in the conclusion than can be found in the premises. The inferential steps consist of rearranging the information in the premises into the form of a conclusion. But if that’s right, then one can logically prove anything at all that one likes just as long as one builds into the premises the information that one wishes to see in the conclusion. (This is exceptionally clear in Kurt Gödel’s version of the ontological argument.)

   (And if the logical system that you’re using doesn’t allow you to rearrange the information in the right way, then you can always change the rules of the system. And as C. I. Lewis argued, the choice between logical systems can only be made on pragmatic grounds: what do you want the logical system to do? If you want it to establish the foundations of arithmetic, an extensional logic is sufficient; if you want it to express how humans reason, when they reason correctly, you will need an intensional logic. Hence the debate over material implication and strict implication, etc.)

   The only tricky part (and I think this is what you were responding to) is to decide on premises that are sufficiently “obvious” that they don’t stand in need of any further argument themselves.

   But the obviousness (or lack thereof) of a premise is entirely dependent on its inferential connection to other elements of one’s own conceptual scheme. There’s no conceptual-scheme independent way of establishing the obviousness or self-evidence of a premise. (This is another way of understanding the sense in which the Given is a Myth.)

3. Incidently, that waht is necessary is necessarily necessary is an axiom in the modal logics that i’ve seen. And it’s intuitive. Let the idea that X is a necessary object or P is a necessary truth be understood to mean that X exists in every possible world or P is true in every possible world. Now suppose that there is indded some object X that can be found in every single possible world. Isn’t it true that there is no possible world in which X does not exist in every possible world?

4. Mung: The necessary entity needs an explanation for it’s existence too, else the argument doesn’t hold water.

   That seems really problematic to me. What could be the explanation for the existence of a necessary being?

   The only thing I can think of is, “because it exists necessarily”.

   But that’s just a tautology, because you’re going to end up saying “the necessary being exists because it necessarily exists”. Since tautologies are vacuously or trivially true, you’re going to end up saying that there must exist a being that has a trivial or vacuous explanation.

   I mean, in a way there’s not much difference between “God’s existence explains God’s existence” and “there is no explanation for God’s existence” — not if explanations are supposed to be informative and not tautologies.

5. Incidently, that what is necessary is necessarily necessary is an axiom in the modal logics that I’ve seen. And it’s intuitive. Let the idea that X is a necessary object or P is a necessary truth be understood to mean that X exists in every possible world or P is true in every possible world. Now suppose that there is indeed some object X that can be found in every single possible world. Isn’t it true that there is no possible world in which X does not exist in every possible world?

6. Sorry about the double post. When I tried to fix the typos in the first one, I got the error message ‘You do not have permission to edit this post.’ When I tried again, I got a new comment instead.

7. keiths:

   The problem here is that you and KN are conflating two dichotomies: contingent/non-contingent and necessary/non-necessary.

   Mung:

   I don’t believe we are. non-contingent == necessary and non-necessary == contingent.

   That’s just an assertion, not an argument. I provided a counterexample:

   For example, you can conceive, perfectly coherently, of a situation in which there are two logically possible universes: one in which A is the non-contingent base on which everything else rests, and one in which B, an entity different from A, serves that role. Logic doesn’t mandate A over B, or vice-versa. Neither is necessary, but both are non-contingent. Their existence, or lack thereof, is just a brute fact, dependent on nothing else.

8. keiths:

   Necessary entities are those that must exist as a matter of sheer logic.

   Mung:

   It seems to me that you are confusing mental entities with ontological entities.

   Huh? How did you get that idea? Necessary entities, if any, necessarily exist — in reality. It’s pure ontology.

   For example, you appear to be arguing for the existence of any number of necessary beings. Yet the argument is that there is only one necessary being and can be only one necessary being.

   Again, where are you getting that? Where have I made an argument regarding the number of necessary beings?

9. Hi everyone,

   I’d like to respond to the skeptical comments by walto and Rumraket about Feser’s rationalist proof of the existence of God. I’ll also address keiths’s remarks on necessity, later on. (I’ll reply to Kantian Naturalist separately.)

   I happen to have a copy of Feser’s Scholastic Metaphysics (2014, editiones scholasticae). The following quotes are taken from pages 142 to 145.

   Premise 2 of Feser’s rationalist argument above went as follows:

   2. If PSR were not true, then things and events without evident explanation or intelligibility would be extremely common.

   How does Feser justify this premise in his book, Scholastic Metaphysics?

   Are there any good positive arguments for PSR? One important argument is a variation on the empirical argument for PC [the principle of causality, which Feser defines on p. 107 as the principle that whatever changes, or comes in to being, or is composite, or contingent, or merely participates in being, has a cause]. Considered as an inductive generalization, PSR is as well-supported as any other. For one thing, we tend to find explanations when we look for them, and even when we don’t we tend to have reason to think there is an explanation but one which, for whatever reason (e.g. missing evidence), we don’t have evidence. For another thing, the world simply doesn’t behave the way we would expect it to if PSR were false (Pruss 2009, p. 32). Events without explanation would surely be occurring constantly and the world would simply not have the intelligibility that makes science and everyday common sense as successful as they are. This would be a miracle if PSR were not true. (pp. 142-143)

   Premise 4 of Feser’s rationalist argument went as follows:

   4. If PSR were not true, then we would be unable to trust our own cognitive faculties.

   Here’s how Feser justifies it:

   One can argue that anyone who denies PSR would, if he is consistent, also have to deny other things he would not deny or even could not coherently deny… Denying PSR, Pruss notes, entails radical skepticism about perception. For if PSR is false, there might be no reason whatsoever for our having the perceptual experiences we have. In particular, there might be no correlation at all between our perceptual experiences and the external objects and events we suppose cause them. Nor would we have any grounds for claiming that such a radical disconnect between our perceptions and external reality is improbable. For objective probabilities depend on the objective tendencies of things, and if PSR is false then events might occur in a way that has nothing to do with any objective tendencies of things. Hence one cannot consistently deny PSR and be justified in trusting the evidence of sensory perception, nor the empirical science grounded in perception.…

   We also suppose that our cognitive faculties track truth and standards of rational argumentation, rather than leading us to embrace conclusions in a way that has no connection to truth or logic. But if PSR is false, we could have no reason for thinking that any of this is really the case. For all we know, what moves or causes us to assent to a claim might have absolutely nothing to do with the deliverances of our cognitive faculties, and our cognitive faculties themselves might in turn have the deliverances they do in a way that has nothing to do with truth or standards of logic. We might believe what we do for no reason whatsoever, and yet it might also falsely seem, one again for no reason whatsoever, that we do believe what we do on good rational grounds. Now this would apply to any grounds we have for doubting PSR as much as it does to any other conclusion we might draw. Hence to doubt or deny PSR undercuts any ground we could have for doubting or denying PSR. The rejection of PSR is self-undermining… To reject PSR is to undermine the possibility of any rational inquiry. (pp. 143-144)

   Premise 4 of Feser’s rationalist argument went as follows:

   6. Furthermore, there is no principled way to deny the truth of PSR while generally accepting that there are genuine explanations in science and philosophy.

   Here’s how Feser justifies it:

   Some philosophers have taken the view that there can be genuine scientific explanations, including scientific explanations, even if PSR is false.… The idea is that we can explain at least some phenomena in terms of laws of nature, those laws in terms of more fundamental laws, and perhaps these in terms of some most fundamental set of laws. The most fundamental laws would, however, lack any explanation. That the world is governed by them would just be an unintelligible “brute fact.”

   But it is far from clear that this is coherent. Suppose I told you that the fact that a certain book has not fallen to the ground is explained by the fact that it is resting on a shelf, but that the fact that the shelf has not fallen to the ground has no explanation at all but is an unintelligible brute fact. Have I really explained the position of the book? It is hard to see how… The “explanation” the shelf provides in such a case would be completely illusory.…

   By the same token, it is no good to say: “The operation of law of nature C is explained by the operation of law of nature B, and the operation of B is explained by the operation of law of nature A, but the operation of A has no explanation whatsoever and is just an unintelligible brute fact.” (pp. 144-145)

   I hope that the foregoing quotes shed light on Feser’s thinking. He is not simply making gratuitous assertions; rather, he is deploying reductio ad absurdum arguments against the critics of PSR, in order to show them that if they deny PSR, they’ll have to give up trusting the veridicality of their perceptions, the overall reliability of their cognitive processes, and the ability of science to provide genuine explanations.

   For me, however, the most dubious premises of Feser’s argument were premises 19 and 24, which need a lot more work, in my humble opinion.

   19. A necessary being would have to be purely actual, absolutely simple or noncomposite, and something which just is subsistent existence itself.

   24. Something which is purely actual, absolutely simple or non-composite, and something which just is subsistent existence itself must also be immutable, eternal, immaterial, incorporeal, perfect, omnipotent, fully good, intelligent, and omniscient.

   Premise 19 is not self-evident, because it is far from clear that a necessary being would have to be “existence itself.” All that follows is that it could not be a composite of essence and existence, which means that such a Being would have to be identical to its own act of existence – which is quite different from saying that such a Being would have to be Existence itself. Feser makes a similar fudge in his book Aquinas (Oneworld Publications, Oxford, 2009), where he draws upon an argument put forward by Aquinas in his De Ente et Essentia:

   If essence and existence were not distinct, they would be identical; and they could be identical only in “something whose quiddity is it very act of existing … such that it would be subsistent existence itself” (DEE 4). That is to say, something whose essence is its existence would depend on nothing else (e.g. matter) for its existence, since it would just be existence or being. (p. 30)

   Sorry, but that last part doesn’t follow. From “X’s essence its X’s existence” we cannot legitimately infer: “X’s essence its Pure Existence.” So Feser needs to do some extra work on Premise 19. It seems to me that if he wants to prove the uniqueness of God, he’d be better off appealing to God’s infinitude rather than His being identical with Pure Existence. That takes us to Premise 24.

   Premise 24 needs work, as well. It simply doesn’t follow that something which is subsistent existence itself is intelligent, let alone omniscient.

   Of course, one way in which Feser might argue for this conclusion is by appealing to the Scholastic principle (Thomistic Thesis 2) that whatever is limited, is limited by its potential rather than its actual properties; hence a purely actual Being (like the Uncaused Cause) would have to be unlimited. But I’m not at all sure that this principle is correct. Consider a triangle. It’s limited, by virtue of its size and shape. Those are actual rather than potential properties. Hence actual properties can be self-limiting, after all.

   Perhaps one could argue instead that while actual properties can be self-limiting, it is only because of the way they constrain one another. Hence a Being Whose essence is simple and Which is not defined by a multiplicity of properties could not be self-limiting and would therefore have to be unlimited. I don’t know; I’m just making a proposal here.

   I’d now like to respond to some comments made by readers above.

   walto

   Neither 2 nor 3 is obvious and ought to be put as a premise. 4 is not obvious and does not follow from anything above it. I agree with 5, but it should be acknowledged that it’s an axiom, i.e., a premise that can’t really be defended (except maybe by noting the success of an entire system–that one has chosen to accept). 6 (again) is neither obvious nor follows from anything above it. Finally, 8 wouldn’t follow even if all the premises above it were true. The only premises in there that are OK are 1 and 7 and none of the inferences is valid.

   I hope I’ve shown that premises 2, 4 and 6 are capable of being justified. Premise 3 is obvious enough to me: I don’t know why walto would contest it. Premise 8 follows because Feser has just put forward three converging arguments for the truth of PSR, any one of which would suffice to demonstrate 8.

   Rumraket writes:

   It is far from clear to me why it must be the case that if there are some things that have no explanation, things without explanation must be extremely common.

   Imagine the following being true: 99.9999999999999999999 (insert any finite number of 9’s here)% of all things have an explanation. Then it seems to me it would be exceptionally rare for things to have no explanation. This is entirely compatible with the world we observe.

   Feser isn’t arguing that if there are some things that have no explanation, things without explanation must be extremely common; rather, he’s arguing that (i) if there are some things that have no explanation, things without explanation could be extremely common, and that (ii) we could never have rational grounds for believing that things without explanation are not (in fact) extremely common. That was the point of his reductio arguments.

   Finally, keiths writes:

   Contingent entities are those that depend on something else for their existence. Non-contingent entities don’t depend on anything else for their existence.

   Necessary entities are those that must exist as a matter of sheer logic. Non-necessary entities are those who existence is not mandated by logic alone.

   While necessary entities must be non-contingent,* it isn’t true that non-contingent entities must be necessary.

   Sorry, keiths, but that’s not how philosopher define either contingency or necessity. A contingent entity is one which doesn’t have to exist, and which is therefore capable of non-existence. A necessary entity is one which does have to exist, and which is therefore incapable of non-existence.

   Your definition of contingency is what I would call dependency. A denier of PSR would assert that there are some beings which are contingent, yet independent. They just hang upon nothing, as it were.

   Your definition of necessity is too narrow, since the only form of necessity it allows for is logical necessity. There are, however, other forms of necessity recognized by philosophers: ontological (or metaphysical) necessity, nomological necessity, physical necessity, and so on. Hope that helps.

10. Hi Kantian Naturalist,

    I’d now like to address your criticisms of the Five Proofs put forward by Feser.

    1. The Aristotelian proof assumes an Aristotelian conception of change, which can hardly be taken for granted. With that assumption in place, the Aristotelian argues that there must be a pure activity or pure actuality. But there’s no reason to think that pure actuality has any of the attributes assigned to God, such as personality or will. Even Aristotle, who thought of pure actuality as an unmoved mover by virtue of being thought thinking itself, did not think that the unmoved mover had personality or will.

    Let me note for the record that Feser is not a theistic personalist. I’m sure he would heartily disagree with the notion that the Unmoved Mover has “personality,” although he would ascribe intellect and will to the Unmoved Mover. In that sense, and that sense only, would he describe God as personal.

    In my opinion, Aristotle’s concept of change isn’t needed for the argument to work. All we need to grant is that there are beings whose nature contains a mixture of “ises” and “isn’ts,” which means that they are incompletely actualized. (This would be true even in an Einsteinian “block time” universe, in which change never happens.) If we then argue that any incompletely actualized being requires some other being to explain its actualization, then we are led to a fully switched on, unactualized Actualizer.

    To see why such a Being would be intelligent, one needs to go along with Aristotle’s view of what the intellect does: abstract universals from particulars. And for Aristotle, whatever is particular possesses some underlying potency, which limits it to the here-and-now. Universal concepts are free from such limitations. A purely actual Being could contain universals within itself (at least implicitly).

    Aquinas clarifies the underlying thinking in his Summa Theologica I, q. 75, art. 2:

    …[I]f the intellectual principle contained the nature of a body it would be unable to know all bodies. Now every body has its own determinate nature. Therefore it is impossible for the intellectual principle to be a body. It is likewise impossible for it to understand by means of a bodily organ; since the determinate nature of that organ would impede knowledge of all bodies; as when a certain determinate color is not only in the pupil of the eye, but also in a glass vase, the liquid in the vase seems to be of that same color.

    Aristotle’s God, being free of bodily limitations, would therefore be capable of receiving the universal forms of all things.

    Back to your remaining arguments.

    2. The Neoplatonic proof only requires that there be simples (non-composite beings). It doesn’t show that there must be one simple. A plurality of non-composite beings would do just as well, as far as that argument is concerned.

    Fair point. However, Plato and his Neoplatonic followers also asserted that Being, Goodness, Truth and Unity are transcendentals. For the Neoplatonists, there could not be two perfect unities. Since an absolutely simple being would constitute a perfect unity, it follows that there can only be one such being. I’m just sketching the argument here: it seems to me that what’s being presupposed in Feser’s argument for God’s unity is that an absolutely simple being would have to be Being Itself.

    3. The Augustinian proof relies on the assumption that there are real universals, and that real universals can only exist as ideas in the divine mind. But are there real universals? One would first have to settle the debate between nominalism, realism, and conceptualism about universals before establishing a proof for the existence of God on that basis. Since the proof of God’s existence depends on realism about universals, one cannot appeal to God in order to settle that debate without begging the question.

    Feser says quite a lot about the debate between nominalism, realism and conceptualism about universals, in his book, Scholastic Metaphyscs (2014). Very briefly: “If we say that our concepts and general terms reflect nothing extra-mental or extra-linguistic, then we shall have to provide an account of how they are formed in a way that makes no reference to mind-independent and language-independent universal essences. But this is not possible.” (p. 225)

    Feser, by the way, is a moderate realist, not a Platonist. He writes: “Moderate realism, then, is moderate, insofar as it involves no commitment to the metaphysical and epistemological baggage of Platonism. There are, for the moderate realist, no such things as mind-independent abstract objects… Moderate realism is realist insofar as, unlike Lockean conceptualism, it takes essences really to exist in individual things themselves, so that even though the essences are universal only as abstracted by the intellect, the conceptual product of this abstractive activity has a foundation in a mind-independent reality.” (p. 227)

    There’s a lot more in Feser’s book, but due to constraints of space, I’ll stop there.

    4. The Thomistic proof correctly shows that there must be a necessary being, but as with the first and second proofs, nothing there establishes that the necessary being must have any (let alone all) of the divine attributes.

    Once again, Feser argues that the divine attributes can be deduced from the fact that a necessary Being cannot be a compound of essence and existence and must therefore be Pure Existence. I think the last part of his argument is over-hasty, however, for reasons explained in my post above.

    5. The rationalist proof assumes a very strong version of the principle of sufficient reason, but why should that be granted? There’s lacuna between “for all facts, there is an explanation of that fact” and “there is one explanation for all facts”. In fact one cannot derive the latter statement from the former in first-order symbolic logic without committing a formal logical fallacy. Hence anyone who accepts that there is an explanation for each fact should not infer that there is one explanation for all facts. And without that latter claim this proof also fails.

    The rationalist proof assumes a very modest version of the Principle of Sufficient Reason. It merely says that there is an adequate explanation for any state of affairs S. It doesn’t say “a determining explanation,” which guarantees the occurrence of S.

    By the way, Feser certainly does not leap from the premise, “For all facts, there is an explanation of that fact” to the unwarranted conclusion, “There is one explanation for all facts.” Rather, the point of PSR is simply to assert that for any fact, there must be something (or things) which is adequate to explain it. That’s all. The inference to a Being Who explains all states of affairs is made only after it is shown that such a Being is Existence Itself.

    I hope that sheds some light on Feser’s thinking. Please bear in mind that I don’t have a copy of Feser’s latest new book yet. Hopefully Mung can fill in any gaps that I’ve left in my explanation of the arguments he puts forward. Cheers.

11. vjtorley: Premise 2 of Feser’s rationalist argument above went as follows:

    2. If PSR were not true, then things and events without evident explanation or intelligibility would be extremely common.

    That seems almost certainly false.

    According to PSR, there is not a single exception.
    According to premise 2, if PSR is false, then exceptions should be abundant.

    The implication: if a single exception exists, then exceptions must be abundant.

    And that seems absurd.

12. vjtorley: Feser isn’t arguing that if there are some things that have no explanation, things without explanation must be extremely common; rather, he’s arguing that (i) if there are some things that have no explanation, things without explanation could be extremely common, and that (ii) we could never have rational grounds for believing that things without explanation are not (in fact) extremely common. That was the point of his reductio arguments.

    Thank you for putting some more meat on premise 2. I still see problems with it through.

    “(i) if there are some things that have no explanation, things without explanation could be extremely common”

    All you need to respond with here is “they also could be extremely rare”. You don’t establish a trend or principle by merely mentioning one among several mere logical possiblities.
    As it stands, Feser seems to be saying that because they COULD be extremely common, we SHOULD believe they are extremely common. That’s simply invalid logic.
    The very same thinking can be turned right on it’s head: Because they COULD be extremely rare, we SHOULD believe they are extremely rare.

    ” and that (ii)we could never have rational grounds for believing that things without explanation are not (in fact) extremely common.”

    Sure we could, we could simply observe that they are extremely rare, but nevertheless not absolutely without precedent.

    One could argue that things like conscious experience, the values of the physical constants, and the very existence of causality, or the universe itself, are counterexamples that throws the PSR into doubt.

    If Feser is willing to draw from general scientific observations(as he does), empirical support in favor of the PSR, then that very thing can be turned against him, since it seems to be the case that we have in fact discovered things for which no
    “account” is even possible. One of those could be the particular qualities of conscious experience (like the “redness experience” of red), which is held by some to be fundamentally irreducible and inexplicable even in princple.

13. Kantian Naturalist: A few years ago I had the following worry about the nature of logical proofs. In a deductive argument, for it to be deductive, there can’t be any more information in the conclusion than can be found in the premises. The inferential steps consist of rearranging the information in the premises into the form of a conclusion. But if that’s right, then one can logically prove anything at all that one likes just as long as one builds into the premises the information that one wishes to see in the conclusion.

    That’s theology in a nutshell.

14. vjtorley,

    Here’s a worry about Feser’s interpretation of the PSR. Feser is willing to treat the PSR as an empirical generalization. More precisely, it’s a meta-induction over the history of empirical inquiry. (We can treat it as a meta-induction because it’s an induction about induction.) But as a meta-induction, it’s vulnerable to Hume-style (as well as Goodman-style) worries about induction.

    We can put this as follows: just because looking for explanations for empirical phenomena has been successful in past acts of inquiry, there’s no guarantee that it will continue to be successful in future acts of inquiry.

    Here’s how Peirce understands the PSR, in response to Humean worries:

    every fact of a general or orderly nature calls for an explanation; and logic forbids us to assume in regard to any given fact of that sort that it is of its own nature absolutely inexplicable. This is what Kant calls a regulative principle, that is to say, an intellectual hope. The sole immediate purpose of thinking is to render things intelligible; and to think and yet in that very act to think a thing unintelligible is a self-stultification. … True, there may be facts that will never get explained; but that any given fact is of the number, is what experience can never give us reason to think; far less can it show that any fact is of its own nature unintelligible. We must therefore be guided by the rule of hope, and consequently we must reject every philosophy or general conception of the universe, which could ever lead to the conclusion that any given general fact is an ultimate one. We must look forward to the explanation, not of all things, but of any given thing whatever.

    Notice that Peirce calls the PSR “the rule of hope”. That seems right to me. We may certainly hope that it will, and surely that intellectual hope or faith sustains the practice of empirical inquiry. I’m not contesting that! But that seems far too slender a reed upon which to hang any deductively valid argument showing that God must exist, which is how Feser seems to treat it.

15. vjtorley: Feser says quite a lot about the debate between nominalism, realism and conceptualism about universals, in his book, Scholastic Metaphysics (2014). Very briefly: “If we say that our concepts and general terms reflect nothing extra-mental or extra-linguistic, then we shall have to provide an account of how they are formed in a way that makes no reference to mind-independent and language-independent universal essences. But this is not possible.” (p. 225)

    I disagree with Feser entirely on this specific point: Wilfrid Sellars shows exactly how this is not only possible but in fact the case!

16. Vincent,

    Like many words, ‘contingent’ and ‘necessity’ have multiple meanings. I am using the meanings best suited to the current discussion.

    A contingent entity cannot serve as the ultimate basis on which everything else rests, precisely because it is contingent in the sense of ‘dependent’. Here’s the Merriam-Webster definition for that sense of the word:

    4 : dependent on or conditioned by something else · Payment is contingent on fulfillment of certain conditions. · a plan contingent on the weather

    As for ‘necessity’, we are talking about logical necessity here (and metaphysical necessity, since it’s a superset of logical necessity). We aren’t talking about nomological or physical necessity.

    Given that logical necessity and dependent contingency are the appropriate senses of the words for the purposes of this discussion, take another look at my assertions:

    While necessary entities must be non-contingent,* it isn’t true that non-contingent entities must be necessary.

    For example, you can conceive, perfectly coherently, of a situation in which there are two logically possible universes: one in which A is the non-contingent base on which everything else rests, and one in which B, an entity different from A, serves that role. Logic doesn’t mandate A over B, or vice-versa. Neither is necessary, but both are non-contingent. Their existence, or lack thereof, is just a brute fact, dependent on nothing else.

    *And even that is debatable, depending on a nuance we can discuss later, if necessary.

17. vjtorley:

    Let me note for the record that Feser is not a theistic personalist. I’m sure he would heartily disagree with the notion that the Unmoved Mover has “personality,” although he would ascribe intellect and will to the Unmoved Mover. In that sense, and that sense only, would he describe God as personal.

    He’s a Christian, right? If so, he presumably ascribes love to God. Christianity rings pretty hollow if you deny John 3:16.

18. Kantian Naturalist: A few years ago I had the following worry about the nature of logical proofs. In a deductive argument, for it to be deductive, there can’t be any more information in the conclusion than can be found in the premises. The inferential steps consist of rearranging the information in the premises into the form of a conclusion. But if that’s right, then one can logically prove anything at all that one likes just as long as one builds into the premises the information that one wishes to see in the conclusion.

    Isn’t this more like a worry about rationality itself? There is a solution to the problem, but you probably prefer to squirm.

19. KN,

    A few years ago I had the following worry about the nature of logical proofs. In a deductive argument, for it to be deductive, there can’t be any more information in the conclusion than can be found in the premises. The inferential steps consist of rearranging the information in the premises into the form of a conclusion. But if that’s right, then one can logically prove anything at all that one likes just as long as one builds into the premises the information that one wishes to see in the conclusion.

    Why is that a “worry”? It’s just another way of stating the well-known fact that arguments can be valid without being sound. Premises matter; you need valid inferences and true premises to reach a sound conclusion.

20. I can prove that Queen Elizabeth is a hamster:

    P1. Elizabeth II is the Queen of England.
    P2. Queens are monarchs.
    P3. All monarchs are hamsters.

    C: Queen Elizabeth is a hamster.

    Valid but not sound.

21. Somehow I just knew that if I googled that conclusion, I would get at least one hit:

22. @keiths
    Heh, you ruined it. The solution is indeed to pay attention that you have sound premises, not just valid chain of inferences. Not sure though if KN believes that soundness is determinable. Maybe he thinks the concept of soundness is as incoherent as PSR.

23. Erik: Isn’t this more like a worry about rationality itself? There is a solution to the problem, but you probably prefer to squirm.

    No, it’s not a problem about rationality itself. It’s a feature of deductively valid arguments. Rationality is not limited to deductively valid arguments.

24. vjtorley: Your definition of contingency is what I would call dependency. A denier of PSR would assert that there are some beings which are contingent, yet independent.

    Then keiths quotes a definition from Merriam-Webster’s which confirms this.

    keiths: 4 : dependent on or conditioned by something else · Payment is contingent on fulfillment of certain conditions. · a plan contingent on the weather

25. How many Angels can dance with a pin-head?

26. Mung likes attention. There’s no limit as far as he’s concerned.

27. Richardthughes:
    How many Angels can dance with a pin-head?

    Simple…all of them… 😉

28. I find this OP confusing (not Mung’s fault) and some comments even more confusing or even disturbing… I’m going to stay out of this…

29. Thanks for your comments, Vincent. I’ll comment on a few of them now, and maybe take up more of them later.

    vjtorley: One can argue that anyone who denies PSR would, if he is consistent, also have to deny other things he would not deny or even could not coherently deny… Denying PSR, Pruss notes, entails radical skepticism about perception. For if PSR is false, there might be no reason whatsoever for our having the perceptual experiences we have. In particular, there might be no correlation at all between our perceptual experiences and the external objects and events we suppose cause them. Nor would we have any grounds for claiming that such a radical disconnect between our perceptions and external reality is improbable. For objective probabilities depend on the objective tendencies of things, and if PSR is false then events might occur in a way that has nothing to do with any objective tendencies of things. Hence one cannot consistently deny PSR and be justified in trusting the evidence of sensory perception, nor the empirical science grounded in perception.…

    We also suppose that our cognitive faculties track truth and standards of rational argumentation, rather than leading us to embrace conclusions in a way that has no connection to truth or logic. But if PSR is false, we could have no reason for thinking that any of this is really the case. For all we know, what moves or causes us to assent to a claim might have absolutely nothing to do with the deliverances of our cognitive faculties, and our cognitive faculties themselves might in turn have the deliverances they do in a way that has nothing to do with truth or standards of logic. We might believe what we do for no reason whatsoever, and yet it might also falsely seem, one again for no reason whatsoever, that we do believe what we do on good rational grounds. Now this would apply to any grounds we have for doubting PSR as much as it does to any other conclusion we might draw. Hence to doubt or deny PSR undercuts any ground we could have for doubting or denying PSR. The rejection of PSR is self-undermining… To reject PSR is to undermine the possibility of any rational inquiry. (pp. 143-144)

    The main problem here is the undefined use of “might.” For example, from

    Possibly, there is no correlation between our perceptual experiences and the external world

    or

    There might be no reason whatsoever for our having the perceptual experiences we have.

    one CANNOT correctly infer that

    We are not justified in trusting the evidence of sensory perception, nor the empirical science grounded in perception.

    Propositions can be justified even if it’s possible that everything that is reasonable to believe is false.

    The excerpted paragraphs above are chock full of that sort of confusion. This diagnosis isn’t particularly new or deep; I’m just pointing out the quite comment fallacy of confusing metaphysical with epistemic possibility. That is, if one says It might be the case that the world is flat, one could mean, either

    (1) Possibly, the earth is flat; or
    (2) For all I know, the earth is flat.

    But while (1) is true, (2) is false. Many epistemologists hold that perceptual experiences provide some sort of prima facie warrant, so that every such experience could be misleading without it following that nobody is justified in believing anything. In such a case, people who are justified would nevertheless be wrong. Thus the falsity of PSR does NOT entail radical skepticism about perception. That claim is simply the result of one or more fallacious inferences.

    With respect to premise (3), the claim that science and common sense generally don’t find and never expect to find things, properties or events without explanations, I repeat that it doesn’t seem obvious to me and seems certainly to contradict the most popular interpretation of quantum mechanics.

30. Thanks too, vincent, for your fleshing out of premise (2), which you did a nice job on. FWIW, I don’t think Rum’s response of

    All you need to respond with here is “they also could be extremely rare”. You don’t establish a trend or principle by merely mentioning one among several mere logical possiblities.

    is on point. Feser’s not trying to establish a trend. But, IMO the entire argument gets muddled, by the use of “explanation” in the first place. It’s a term with one foot in the causal world and another in epistemology. Spinoza plays on that ambiguity throughout his Ethics.

31. Erik,

    @keiths
    Heh, you ruined it. The solution is indeed to pay attention that you have sound premises, not just valid chain of inferences. Not sure though if KN believes that soundness is determinable. Maybe he thinks the concept of soundness is as incoherent as PSR.

    Having flounced, KN is in the awkward position of not responding to me, so we may never get to hear why the soundness/validity distinction is a “worry” for him when it’s obvious and unproblematic for everyone else.

32. Mung,

    Where did you get the odd ideas I pointed out in this comment?

    You really, really need to work on your reading comprehension.

33. Ditto for this comment of yours:

    vjtorley: Your definition of contingency is what I would call dependency. A denier of PSR would assert that there are some beings which are contingent, yet independent.

    Then keiths quotes a definition from Merriam-Webster’s which confirms this.

    keiths: 4 : dependent on or conditioned by something else · Payment is contingent on fulfillment of certain conditions. · a plan contingent on the weather

    It’s a refutation, not a confirmation. Vincent’s claim is that I’m talking about dependency, not contingency. The Merriam-Webster definition refutes that.

    Again: learn to read for comprehension, Mung.

34. Feser’s actual “proofs”:

    1) I’m insecure
    2) I’m illogical
    3) I’m gullible
    4) I’m angry
    5) I’m an idiot

35. Robin:
    Feser’s actual “proofs”:

    1) I’m insecure
    2) I’m illogical
    3) I’m gullible
    4) I’m angry
    5) I’m an idiot

    So…you are Feser… I could have sworn you were Rober Byers…

    BTW: If you have “poofs” issues, it is best to see a gasstrologyst as their “poofs” are one of their specialties…

    Here is a link to one:

    https://www.youtube.com/watch?v=FdghRwWfaOQ

36. walto: t, IMO the entire argument gets muddled, by the use of “explanation” in the first place. It’s a term with one foot in the causal world and another in epistemology. Spinoza plays on that ambiguity throughout his Ethics.

    I’d hardly want to accuse Spinoza and Feser of the same error; that does Feser far too much honor and credit.

    Spinoza’s error was to conflate causation and inference, because distinguishing between what is the case (in our explanation of causes) and what should be the case (in our understanding of reasons) requires being able to make sense of the causes/reasons distinction. Spinoza conflated reasons and causes, on the one hand assimilating logic and reasoning to mechanism, and on the other hand endowing mechanism with the strict necessity of deductive inference. He did so because he thought that the only way of making sense of normativity required teleology, and teleology is inconsistent with a mechanistic universe comprehensible through (17th-century) mathematics alone. But given the nearly total absence of biology and sociology in Spinoza’s day, it’s astonishing that he came as close to the truth as he did.

    Apart from that, you’re quite right to distinguish between metaphysical possibility and epistemic possibility, or put otherwise, between truth and justification. (Would you align those distinctions in that way, though?) One can be adequately justified in believing something that is, for all one can tell, false. (Geocentrism, spontaneous generation, phlogiston theory, and ether theory all come to mind.) The logical possibility of ~x doesn’t mean that one isn’t justified in believing x. Whether one is justified in believing x depends on what evidence is available to you at the time.

    In any event, there’s just no argument here that abandoning the PSR, whether in the demanding version of the rationalists or the ‘rule of hope’ version of the pragmatists, has anything to do with our trust in our cognitive abilities.

37. vjtorley,

    Hi Vincent

    Do you think that Feser has brought forth any real new ideas not pre existing in Aquinas’s works.

38. Hi everyone,

    I’d like to respond to a few comments. Before I continue, I’d like to point out that Feser’s lengthy argument, posted online by Mung, contained three separate arguments for the Principle of Sufficient Reason (PSR), which I spelt out at length in a comment above, quoting from Feser’s Scholastic Metaphysics to elucidate the underlying logic. In a nutshell, the arguments were as follows:

    2. If PSR were not true, then things and events without evident explanation or intelligibility would be extremely common.

    4. If PSR were not true, then we would be unable to trust our own cognitive faculties.

    6. Furthermore, there is no principled way to deny the truth of PSR while generally accepting that there are genuine explanations in science and philosophy.

    In order to rebut Feser’s arguments for PSR, you need to refute all three arguments, not just the first.

    Having made that point, I’d now like to address some specific criticisms that were made of Feser’s arguments.

    Neil Rickert,

    According to premise 2, if PSR is false, then exceptions should be abundant.

    The implication: if a single exception exists, then exceptions must be abundant.

    And that seems absurd.

    This is a criticism of the argument which is summarized in Feser’s premise 2 of his Rationalist Proof for God’s Existence> However, it leaves the arguments summarized in premises 4 and 6 untouched.

    If I understand Feser aright, he seems to be arguing as follows. First, he makes a rhetorical argument. Suppose that things really could happen for absolutely no reason. Why should that be a rare occurrence? Why should events which happen for no reason be so hard to find? And yet they are.

    Second, we can bolster Feser’s case here by recasting it in Bayesian terms. On the hypothesis that PSR is false, the probability that we should live in a world where events which happen for no reason are either very rare or non-existent would seem to be quite low: such events must just as well be very common. But on the hypothesis that PSR is true, the probability that we should live in a world where events which happen for no reason are either very rare or non-existent is 100%. Hence the lawfulness of the cosmos counts as evidence which favors PSR. (Of course, that doesn’t necessarily make it true. If one happens to believe that the prior probability of PSR is very, very low, then one will have to collect a massive amount of evidence for PSR before belief in the principle becomes rationally warranted.)

    I imagine an evolutionist might attempt to reply to Feser’s argument by distinguishing: on the hypothesis that PSR is false, the probability that any given world (in the multiverse) should be one where events which happen for no reason are either very rare or non-existent would indeed be very low. However, the probability that we should live in a world where events which happen for no reason are either very rare or non-existent would actually be very high, because a world in which events which happened for no reason were very common would likely be fatal to life. Such a world would be too dangerous to live in: there’d be too many accidents. Hence life-friendly worlds have to be ones where PSR has very few exceptions.

    However, the argument assumes that life is inherently fragile: in other words, it assumes that life-forms themselves need to be stable over time, and that instability threatens their very existence. But if PSR is false, that claim may be untrue. Plants, animals and people might all suddenly sprout new body parts or lose old ones, in a world where PSR didn’t hold.

    Rumraket,

    As it stands, Feser seems to be saying that because they COULD be extremely common, we SHOULD believe they are extremely common. That’s simply invalid logic.

    The very same thinking can be turned right on its head: Because they COULD be extremely rare, we SHOULD believe they are extremely rare.

    See my comments above, in response to Neil Rickert. I think Feser is implicitly appealing to Bayesian reasoning here. In any case, the logic underlying premises 4 and 6 of Feser’s argument (which I sketched out, above) still needs to be addressed.

    If Feser is willing to draw from general scientific observations (as he does), empirical support in favor of the PSR, then that very thing can be turned against him, since it seems to be the case that we have in fact discovered things for which no “account” is even possible. One of those could be the particular qualities of conscious experience (like the “redness experience” of red), which is held by some to be fundamentally irreducible and inexplicable even in principle.

    This is an interesting argument. I must confess that qualia strike me as very, very odd. However, I’m not at all persuaded that no explanation can be given for qualia, even in principle. After all, they are related to one another: the color orange, which is next to red on the spectrum, is also the spectral color whose qualia are most similar to those for the color red. Why should this be so, if qualia are radically inexplicable?

    Kantian Naturalist,

    Here’s a worry about Feser’s interpretation of the PSR. Feser is willing to treat the PSR as an empirical generalization. More precisely, it’s a meta-induction over the history of empirical inquiry. (We can treat it as a meta-induction because it’s an induction about induction.) But as a meta-induction, it’s vulnerable to Hume-style (as well as Goodman-style) worries about induction.

    We can put this as follows: just because looking for explanations for empirical phenomena has been successful in past acts of inquiry, there’s no guarantee that it will continue to be successful in future acts of inquiry.

    I share your worries about induction. Indeed, I’m so concerned about it that I think positing the existence of a God Whose wisdom is unlimited and Who wants to be known by His rational creatures is the only way to solve the problem. I’ve written an article on this point here:

    Does scientific knowledge presuppose God? A reply to Carroll, Coyne, Dawkins and Loftus.

    In any case, I don’t think Feser is treating PSR as a meta-induction over the history of empirical inquiry, as you put it. Instead, he’s using a Bayesian argument, as I construe it (see my remarks to Neil Rickert above).

    In any case, your criticism of Feser’s underlying logic doesn’t address premises 4 and 6 in his Rationalist proof, which I consider to be much deeper and more insightful arguments.

    I disagree with Feser entirely on this specific point: Wilfrid Sellars shows exactly how this is not only possible but in fact the case!

    That sounds interesting.Would you care to elaborate?

    keiths,

    He’s a Christian, right? If so, he presumably ascribes love to God. Christianity rings pretty hollow if you deny John 3:16.

    Feser is indeed a Christian: he’s a conservative Catholic philosopher. And yes, he believes that God loves us. However, he also believes that God’s love is more unlike our own than like it: God’s love, for instance, is not a feeling, as human love often is. God’s love for an individual simply means that He wants what is ultimately best for that individual. That’s all.

    While necessary entities must be non-contingent,* it isn’t true that non-contingent entities must be necessary.

    For example, you can conceive, perfectly coherently, of a situation in which there are two logically possible universes: one in which A is the non-contingent base on which everything else rests, and one in which B, an entity different from A, serves that role. Logic doesn’t mandate A over B, or vice-versa. Neither is necessary, but both are non-contingent. Their existence, or lack thereof, is just a brute fact, dependent on nothing else.

    What you’re arguing here is that the nature of an independent Being (or Uncaused Cause) remains undetermined, if PSR does not hold and brute facts are possible. And I would agree that you’re quite right, if you grant those assumptions. However, Feser doesn’t. The real question that needs to be addressed is: suppose PSR is true, what follows regarding the nature of God? What can we deduce about Him?

39. Hi walto,

    I’d now like to address your criticism of Feser’s premise 4:

    The main problem here is the undefined use of “might.” For example, from

    Possibly, there is no correlation between our perceptual experiences and the external world

    or

    There might be no reason whatsoever for our having the perceptual experiences we have.

    one CANNOT correctly infer that

    We are not justified in trusting the evidence of sensory perception, nor the empirical science grounded in perception.

    I think you have a valid point here. However, I think your criticism overlooks this passage in Feser’s argument:

    Nor would we have any grounds for claiming that such a radical disconnect between our perceptions and external reality is improbable. For objective probabilities depend on the objective tendencies of things, and if PSR is false then events might occur in a way that has nothing to do with any objective tendencies of things.

    I think Feser’s argument is of the following form, where premise 1 serves merely to introduce premise 2:

    1. If PSR is false, then there might be no reason whatsoever for our having the perceptual experiences we have.

    2. What’s more, if PSR is false, then it is not at all improbable that our perceptions will fail to correspond to reality.

    3. We are justified in trusting the evidence of sensory perception only if it is in fact improbable that our perceptions will fail to correspond to reality.

    4. Hence by 2 and 3, we are not justified in trusting the evidence of sensory perception if PSR is false.

    5. But the scientific enterprise is unwarranted unless we are justified in trusting the evidence of sensory perception.

    6. Hence if PSR is false, the scientific enterprise is unwarranted, which is absurd.

    You also write:

    With respect to premise (3), the claim that science and common sense generally don’t find and never expect to find things, properties or events without explanations, I repeat that it doesn’t seem obvious to me and seems certainly to contradict the most popular interpretation of quantum mechanics.

    Physicist David Albert has a very pertinent here, in his scathing review of Lawrence Krauss’s A Universe from Nothing:

    Relativistic-quantum-field-theoretical vacuum states — no less than giraffes or refrigerators or solar systems — are particular arrangements of elementary physical stuff. The true relativistic-quantum-field-­theoretical equivalent to there not being any physical stuff at all isn’t this or that particular arrangement of the fields — what it is (obviously, and ineluctably, and on the contrary) is the simple absence of the fields! The fact that some arrangements of fields happen to correspond to the existence of particles and some don’t is not a whit more mysterious than the fact that some of the possible arrangements of my fingers happen to correspond to the existence of a fist and some don’t. And the fact that particles can pop in and out of existence, over time, as those fields rearrange themselves, is not a whit more mysterious than the fact that fists can pop in and out of existence, over time, as my fingers rearrange themselves. And none of these poppings — if you look at them aright — amount to anything even remotely in the neighborhood of a creation from nothing.

    If he’s right, then quantum mechanics in no way undermines Feser’s premise (3) in his Rationalist Proof for the existence of God.

40. vjtorley: This is a criticism of the argument which is summarized in Feser’s premise 2 of his Rationalist Proof for God’s Existence> However, it leaves the arguments summarized in premises 4 and 6 untouched.

    For me, reasons exist within human culture and communication. But events are not so constrained. So why should there be a required connection between reasons and events?

    The whole idea of the PSR seems obviously foolish.

41. My posts keep getting moved to Guano for no reason. Therefore, PSR is false.

42. Neil Rickert: The whole idea of the PSR seems obviously foolish.

    Is that a brute fact?

43. Mung: Is that a brute fact?

    There are no brute facts.

44. vjtorley,

    I have to say, I really don’t understand any of Feser’s arguments. (And why give us three if one of them were adequate?)

    Let us call “the strong PSR” as saying that every fact must have an explanation. (I’m going to put it this way to indicate how Kantian I am about these things.) Notice the every-must structure to this claim. This makes it a priori, because no a posteriori judgment can justify an every-must claim.

    (Up to this point Leibniz and Kant agree. Their divergence lies in the ground this a priori claim. Needless to say I agree with Kant against Leibniz and with Peirce against Kant: the PSR is a metalinguistic explication of the norms built into our actual but contingent epistemic practices of empirical inquiry. It allows us to say what one must be doing in order for us to build testable models of phenomena as we do.)

    But returning to the strong PSR, what precisely is the connection between the principle that there must be an explanation for every fact and our trust in our cognitive abilities, and in particular our perceptual apparatus?

    For one thing, we don’t actually trust our perceptions — not naively, anyway. We know that what we can perceive is relative to our capacities for bodily movement, and the kinds of sensory receptors that we happen to have, and what we are prepared to expect in our environment. We know that we are prone to hallucinations and optical illusions. Even “veridical” perception is not about being perceptually open to the very nature of reality; it’s about reliably tracking, from one’s embodied and embedded position, the affordances that comprise one’s situation.

    If the strong PSR were false, then not every fact would have an explanation. What then? Only this: that it is possible, for any fact, that it cannot be explained. There are ‘brute facts’. But which facts are brutish? That can only be determined as a result of at least trying to explain them! For it only after inquiry has failed that we can then say, “Ah, this must be one of those brutish facts! Sorry to have wasted your time!”

    In short, rejecting the strong PSR means only that there is no guarantee that inquiry will always be successful.

    And what does that to do with the veridicality of perception, understood above (based on the phenomenology of perception itself) as just our ability to reliably track affordances in our perceptual situation relative to our embodied and embedded orientation in the world?

    So far as I can tell, absolutely nothing at all.

45. Kantian Naturalist: Let us call “the strong PSR” as saying that every fact must have an explanation.

    Feser isn’t arguing for strong PSR. He doesn’t refer to “facts” at all.

    Kantian Naturalist: 5. The rationalist proof assumes a very strong version of the principle of sufficient reason, but why should that be granted? There’s lacuna between “for all facts, there is an explanation of that fact” and “there is one explanation for all facts”.

    That’s not Feser’s argument.

46. Kantian Naturalist: I have to say, I really don’t understand any of Feser’s arguments.

    At least you are not alone…

47. Mung: Feser isn’t arguing for strong PSR. He doesn’t refer to “facts” at all.

    Perhaps he doesn’t use the word “facts,” but as you put it, “everything is intelligible or has an explanation for why it exists and has the attributes it has.” If there’s a difference between that and the concept of a fact, I don’t quite see it. Care to elaborate?

    (Besides, putting the PSR in terms of ‘every fact must have an explanation’ is pretty much standard in how I was taught this stuff. If Feser’s version of the PSR is non-standard, that ought to be made explicit.)

48. … the argument of this chapter by no means requires acceptance of everything that has historically been defended under the label “rationalism” … It is “rationalist” only in the sense that it rejects the idea that there are or could be any inexplicable “brute facts”, but instead takes reality to be intelligible through and through. That is to say, its rationalism consists merely in its commitment to the principle of sufficient reason.

    But it is important to emphasize that even here, the argument by no means requires acceptance of everything that has been defended in the name of PSR.

49. vjtorley: 2. What’s more, if PSR is false, then it is not at all improbable that our perceptions will fail to correspond to reality.

    I’d deny that. If perceptions provide prima facie evidence, they may be said to provide prima facie probability. I don’t see the connection between probability and PSR claimed here. As Rumraket said above explanations may be around in the vast majority of (baseball-sized) cases, maybe even in all of THOSE.

    Which leads to the quantum physics response. I’m certainly not in any position to go toe-to-toe with any physicist on this matter, but it’s my understanding that the majority of physicists hold that what happens in the slit test simply cannot be explained. Period.

    I mean, I happen to like Bohm myself, and he says that there really is some explanation, but we haven’t found it. However, that view is widely derided among experts, I understand. The claim was that scientists would not abide the falsity of PSR; that you have found one guy who disagrees with the consensus is hardly apposite here. The truth is that it was scientists who found themselves in the position of having to convince nearly everybody else on the matter of quantum indeterminism.

    Furthermore, what is the “everything” that’s supposed to have an explanation according to Feser is supposed to consist of? Suppose someone agrees that every event has a cause. Is Feser a physicalist with respect to the mind-body problem? When asked for the cause of my laughing earlier this evening, will he point to a state of my central nervous system? If not, does he hold that there is some endless chain of mental causes? If he holds that persons are the cause of free actions, what’s the cause of this or that person, a sperm cell conjoining with an egg? Does that put one back in the physical realm?

    Anyhow, I’m not sure either what explanations are supposed to be or what the everything that is supposed to have them is supposed to consist of.

50. walto,

    I mean, I happen to like Bohm myself, and he says that there really is some explanation, but we haven’t found it. However, that view is widely derided among experts, I understand.

    Yes, with the objection being that Bohm’s view requires faster-than-light causal interactions between separated physical entities.

    The claim was that scientists would not abide the falsity of PSR; that you have found one guy who disagrees with the consensus is hardly apposite here. The truth is that it was scientists who found themselves in the position of having to convince nearly everybody else on the matter of quantum indeterminism.

    True, although determinism is rescued under the Many Worlds Interpretation of QM. Under MWI, all outcomes are realized deterministically, with the indeterminism being only apparent, depending on which world an observation happens to take place within.

    But at that point Feser’s argument runs into the difficulty you warned against earlier:

    But, IMO the entire argument gets muddled, by the use of “explanation” in the first place. It’s a term with one foot in the causal world and another in epistemology.

    Within any given world, there’s no explanation for the particular result yielded by a quantum measurement, even though the entire multi-world framework is unfolding deterministically.

    Furthermore, what is the “everything” that’s supposed to have an explanation according to Feser is supposed to consist of? Suppose someone agrees that every event has a cause. Is Feser a physicalist with respect to the mind-body problem?

    Given his Thomistic leanings, he’s probably a hylemorphic dualist. Vincent, can you confirm?