- RBrad
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Re: PSR retorsion argument
Sorry it took me a little while to respond. One way of putting it would be that if we hold PSR is false, then there is no reason why the deliverances of our cognitive faculties couldn't be brute facts. To quote from Feser:
In short, either everything has an explanation or we can have no justification for thinking that anything does. No purported middle ground position, on which some things have genuine explanations while others are “brute facts,” can coherently be made out. If there really could be unintelligible “brute facts,” then even the things we think are not brute facts may in fact be brute facts, and the fact that it falsely seems otherwise to us may itself be yet another brute fact. We could have no reason to believe anything. Rejecting PSR entails the most radical skepticism -- including skepticism about any reasoning that could make this skepticism itself intelligible.
And if you want to say, "PSR isn't true for everything, but it is true for our faculties," then you would have to give some reason for holding this position. In other words, if PSR doesn't hold, why should it hold for this one specific domain that includes your faculties?
Last edited by RBrad (6/18/2016 12:01 am)
- Johannes
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Re: PSR retorsion argument
Actually, the last quote from Feser does not explicitely state the retorsion argument, since it can be understood as referring only to external reality, not to the operation of our intellect. Even in this restricted understanding, the argument is not cogent because it is empirically evident that there are things that are not brute facts. Realism is first, rationality is second. Stating that you cannot be sure that anything is rationally explainable unless you presuppose that everything is rationally explainable is against realism.
The quote from Feser which makes the retorsion argument explicit is the first, which I repeat below with some formatting and emphasis, followed by my comments. Briefly, I find the argument unsound.
Feser wrote:
Consider that whenever we accept a claim we take to be rationally justified,
- we suppose not only that we have a reason for accepting it (in the sense of a rational justification) but
- [we suppose] also that this reason is the reason why we accept it (in the sense of being the cause or explanation of our accepting it).
- We suppose that it is because the rational considerations in favor of the claim are good ones that we are moved to assent to the claim.
- 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.
Reading so far, any lucid person will retort that he does not suppose but knows all that. But let's continue with the quote:
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, once again for no reason whatsoever, that we do believe what we do on good rational grounds.
The flaw in the argument is that it is based only on rationality while leaving out realism. Realism is first, rationality is second. It is a matter of mere realism that:
1. In general, there are domains of reality within which facts have a rational explanation. You do not need to hold PSR to know that, if you pull the trigger of a gun, your action is the reason why the gun fires.
2. In particular, the rational operation of our intellect is one of those domains of reality. A hypothetical mathematician Matt does not need to hold PSR to know that:
- he has a reason for accepting a theorem (in the sense of a rational justification, in this case a valid demonstration),
- his perception that there is a valid demonstration is the reason why he accepts the theorem (in the sense of being the cause or explanation of his accepting it),
- it is because he perceives that the demonstration is valid that he is moved to hold the theorem as true,
- his cognitive faculties track truth and standards of rational argumentation, rather than leading him to embrace conclusions in a way that has no connection to truth or logic.
Thus, Matt would probably find the claim that, if PSR is false, he could have no reason for thinking that any of this is really the case, either outrageous or amusing, in any case prompting him to, most rationally, terminate any dialogue with the person making the claim, just as I would have done with Parmenides upon hearing him state that movement was illusory. Seriously, claiming that unless you hold (I) that reality is thoroughly ontologically rational (i.e. rationally explainable) you cannot really hold (II) that your intellect is operationally rational, was a true Parmenidean moment for Feser.
Moreover, since the rationale for going from (I) to (II) is not immediately clear to me, I will work a bit on it. Starting with the standard definition of PSR [1]:
PSR: For every fact F, there must be an explanation why F is the case.
and expanding fact F = {entity X exists, event E occurs, proposition P is true} [2]
PSR.x: For every entity X, if X exists, then there is a sufficient explanation for why X exists.
PSR.e: For every event E, if E occurs, then there is a sufficient explanation for why E occurs.
PSR.p: For every proposition P, if P is true, then there is a sufficient explanation for why P is true.
I will try to go from (I) to (II) by way of PSR.e, with event E being "Matt accepts theorem T as true" and its explanation being: "Matt perceived that the demonstration of the theorem was valid." Now enter RBrad and tells Matt: "=smallIf there really could be unintelligible brute facts, then even the things we think are not brute facts may in fact be brute facts, and the fact that it falsely seems otherwise to us may itself be yet another brute fact. Thus, unless you hold PSR, you cannot be sure that you accept theorem T as true because you perceive that its demonstration is valid. You might accept it as true for no reason whatsoever, and yet falsely believe that you accept it on good rational grounds. Furthermore, neither can you be sure that you accepted each step of its demonstration as correct because you perceived it as such."
The problem with this is that Matt is not an observer of the event, but has personally lived it, going through the demonstration and accepting the theorem after seeing that the demonstration was valid and because of that. Therefore to introduce the possibility of doubt for Matt amounts to question the soundness of his perception of his own mental states, to posit his utter disconnection from his internal reality. This is way further than denial of PSR, and therefore the claim that holding PSR, i.e. (I) is a prerequisite for holding (II) is an unwarranted extrapolation.
So, while the general claim that, unless you hold that there is an explanation for everything, you cannot be certain that there is an explanation for anything, is unsound due to mere realism, the specific claim that you cannot even be certain that your intellect is operationally rational is an extreme case thereof, and will not take you anywhere. (Or maybe it will, as one of the possible actions that Matt will take upon hearing your claim may explain, in compliance with PSR, the prompt arrival of two hefty guys carrying a straightjacket.)
[1]
[2]
- Johannes
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Re: PSR retorsion argument
I will try to formalize my objection to the PSR retorsion argument. Its flaw resides in the break from realism implied in the leap from questioning the intelligibility of the ultimate facts to questioning the accuracy of any rational being in his perception and retention of facts, both external and internal, and his rational processing of those facts.
Viewing a rational being as a self-aware fact perceiver, retainer and rational processor, its operations are (with "->" denoting data flow in a data flow diagram, not the implication logical connective):
As perceiver: Fact (external or internal) -> Perception -> Mental representation of fact.
As retainer: Mental representation of fact remains identical to itself along time.
As rational processor, arguing/explaining: Facts -> Operation according to rules of logic -> Conclusion/Explanation.
The construction of an argument/explanation, the perception thereof as valid, and the acceptance of a conclusive/explanatory fact because its respective argument/explanation is perceived as valid, are all internal facts, specifically events. Turning now to Feser's claims in the first post, doubting that...
it is because the rational considerations in favor of the claim are good ones that we are moved to assent to the claim
... when you perceive clearly that you are assenting to the claim because you perceive that the argument for it is sound, means that your perception of internal facts might be utterly defective. Or if the assent was in the past, it might be your retention of such facts. Or both. Similarly, doubting that...
our cognitive faculties track truth and standards of rational argumentation
... means you might be not only a defective rational processor but also a defective internal fact perceiver or retainer, since you would swear you checked the correctness of each and every step of the argument.
Realistically and rationally, your mental representation of an internal fact F1, specifically an event consisting of your assenting to a claim because you perceive that the argument for it is sound, is itself an internal fact F2, a virtual entity, which is explained by your past perception of internal fact F1. Now Feser wants you to think that, if PSR is false, F2 (your mental representation of event F1) might be a brute fact, and not really explained by your past perception of event F1, which actually never occurred. The problem is that if a PSR denier should allow the PSR retorsion argument to instill in him doubts on his basic accuracy as fact perceiver, retainer and rational processor, his later acceptance of PSR would not be sufficient to clear those doubts, since reality might perfectly be thouroughly rationally explainable while he might still be an utterly defective fact perceiver, retainer and rational processor! Thus, if you allow the PSR retorsion argument to throw you down the hole of doubting your own intellectual faculties, then you cannot get out of that hole by just accepting PSR. Which shows clearly that you should not have allowed the PSR retorsion argument to throw you down that hole in the first place, the reason for the argument's unsoundness being that it implies the denial of not only PSR but also of basic realism.
Thus, assuming your basic accuracy as fact perceiver, retainer and rational processor is (at least an essential component of) a sound foundation for building your whole intellectual edifice, but radically doubting that accuracy and assuming just PSR is not.
Notably, your latest quote from Feser illustrates most clearly the break from realism implied in the PSR retorsion argument:
If there really could be unintelligible “brute facts,” then even the things we think are not brute facts may in fact be brute facts, and the fact that it falsely seems otherwise to us may itself be yet another brute fact. We could have no reason to believe anything.
If, while in a forest, you believe that those ever-closer howls are unintelligible brute facts, and act in accordance to that belief by not taking any precautionary measures, you will promptly be eaten by the wolfs that explain the howls. So, you have the strongest reason to believe that the howls are not brute facts.
As the PSR retorsion argument implies a radical break from realism into pure rationality, its formulation can be described as a true Cartesian moment for Feser (and not "Parmenidean" as I wrote in my previous post, which I cannot edit now probably due to its length).
Last edited by Johannes (6/21/2016 12:19 am)
- RBrad
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Re: PSR retorsion argument
I think you might be misunderstanding Feser's argument. Thanks for the discussion though.
Last edited by RBrad (6/19/2016 10:25 pm)
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