PORCHAT ON EXTERNAL WORLD SCEPTICISM

Invited contribution for Towards Skepticism: Neo-Pyrrhonism and its Critics, (ed.) P. Smith, (Dordrecht, Holland: Springer). PORCHAT ON EXTERNAL WORLD SCEPTICISM DUNCAN PRITCHARD University of California, Irvine [email protected] ORCID: 0000-0002-5997-0752 ABSTRACT. In his ‘Scepticism and the External World’, Oswaldo Porchat offered a compelling diagnosis of what is problematic about external world scepticism. In outline, he claimed that far from this scepticism representing the true critical spirit of philosophy, whereby doubt is extended to its maximal scope, it instead uncritically turns on contentious claims in the philosophy of mind. While broadly sympathetic to this critique, I argue that it nonetheless misses out an important feature of external world scepticism, which is that this is really two radical sceptical arguments in disguise. While these two sceptical arguments are overlapping, they are nonetheless distinct and either can be used to motivate the radical sceptical conclusion. Porchat’s diagnosis, I contend, only targets what is problematic about one of these radical sceptical arguments. I draw out this distinction by comparing how epistemological disjunctivism and Wittgensteinian hinge epistemology responds to external world scepticism. KEYWORDS: Epistemological Disjunctivism; Epistemology; Hinge Commitments; Porchat, Oswaldo; Radical Scepticism; Wittgenstein, Ludwig. 2 1. INTRODUCTORY REMARKS I must confess that prior to being engaged on this project, I hadn’t actually read any of Oswaldo Porchat’s work. Of course, I had heard of him, as his work is widely admired. But I’m not a classicist, and I always thought of Porchat as being a classicist (or at least a philosopher mainly writing on Ancient Greek thought anyway), which put him just outside my remit. For while I have dabbled in the epistemology of ancient Greece, particularly with regard to sceptical and ethical themes, I would never count myself as a specialist in this regard. The invitation to write on Porchat’s work was thus accepted with some trepidation. I felt that this was an excellent opportunity to come to know the works of an important thinker, but I was also hesitant that I had anything significant to say about those works, given their subject matter. Having worked my way through many of his fascinating papers, however, I now think there is at least one weighty aspect of Porchat’s ouevre that I could usefully comment upon. This is his magisterial commentary on external world scepticism in ‘Scepticism and the External World.’1 As we will see, there is much that I agree with in terms of Porchat’s treatment of external world scepticism. Indeed, his writing strikes me as ahead of its time. For example, Michael Williams’s hugely influential book on external world scepticism, Unnatural Doubts: Epistemological Realism and the Basis of Scepticism¾which, completely independently, makes many of the core points that Porchat makes in this paper (first published in 1986)¾doesn’t appear until 1991.2 As we will also see, however, I want to suggest that there is a crucial point that Porchat misses. In particular, I will be arguing that ‘external world scepticism’ is in fact two logically distinct (albeit overlapping) sceptical problems. Moreover, recognising this fact is crucial to offering a complete diagnosis of external world scepticism. If that’s right, then even despite Porchat’s great insight into this philosophical difficulty, there is nonetheless something vital that he overlooked. Before proceeding, I want to make an important procedural point. Porchat is fairly unusual in that his views altered quite extensively over his lifetime. (These shifts are very nicely explained by Plino Smith in the introduction to this volume). Thus when I critique this work of Porchat, I am effectively critiquing a particular viewpoint expressed by Porchat around the time of this paper. The relevance of this is not that I think the distinction 3 between the two underlying arguments for external world scepticism that I claim he overlooks is found elsewhere in his oeuvre, as I’m fairly confident that it isn’t. The point is rather that Porchat’s views on scepticism, at least when considered as a whole, are admittedly more complex than I present them here. It seems clear to me, however, that any attempt to situate Porchat’s stance in ‘Scepticism and the External World’ within his overall writings on scepticism would be well beyond the scope of a single paper. Accordingly, I will not attempt it. As a result, the reader should take my remarks to be largely confined to this particular presentation of Porchat’s views.3 2. PORCHAT ON EXTERNAL WORLD SCEPTICISM Porchat begins his discussion of external world scepticism by interrogating what he terms the “methodological suspension of judgement about the external world” (108).4 This is core to the project of external world scepticism, as it needs to be coherent to undertake such a suspension in order for the project to get underway. And yet, as Porchat argues, it isn’t at all clear what this ‘externality’ amounts to, much less that it is coherent for the external world to be, as he puts it, “placed in brackets” (108) in this way. Interestingly, Porchat describes the philosophical commitment to this methodological suspension as akin to something like ideology: “This methodological stance has become so habitual and seems so natural to us that we do not envisage, at first glance, how one could adopt any other without falling into naive and very little critical dogmatism. This way of seeing things has become so ingrained in our philosophical tradition that many philosophies do not even dwell on considering and clarifying it, let alone discussing it.”5 (108) Put another way, philosophers don’t wish to be seen to be dogmatic, so their critical spirit ironically leads them to uncritically accept something that would be utterly alien (indeed, as we will see, incomprehensible) to the folk, which is to bracket the existence of a world that is external to them. That the suspension is purely methodological is, of course, Descartes’ innovation. It has the useful result that one doesn’t need to actually suspend one’s belief in the external world (which may well be psychologically impossible). One only needs to do it from a purely methodological perspective. This is usually how the crucial contrast between Pyrrhonian 4 scepticism—which is of course an ethical position, in that it represents a way of life—and Cartesian scepticism is often understood. For the Pyrrhonian, scepticism is by its nature a limited enterprise as one needs to be able to live one’s scepticism, and to live one needs to have some commitments (the issue is how extensive these need to be).6 For the methodological scepticism that Descartes envisages, however, there is no such restriction, as we are not now thinking of scepticism as an ethical stance but rather as a methodology; a radical form of doubt that is going to expose the true foundations of our commitments.7 If this radical doubt leads us to conclude that we are unable to determine these foundations, then scepticism now becomes a paradox rather than a position. That is, it is highlighting fundamental contradictions in our own conceptual scheme with regard to such questions as the scope of our knowledge. There is no longer a sceptic, as such—i.e., someone who occupies a radical sceptical position (which is likely impossible, given the radical nature of the doubt involved)—but rather a sceptical argument that motivates this radical sceptical paradox.8 This methodological feature of Cartesian scepticism is thus meant to explain how Cartesian sceptical doubt can be universal, thus ensuring that this is a form of scepticism which is (as we now describe it) radical. Note that Porchat’s concern with Cartesian scepticism is not directly with the universality of doubt in play, than with the coherence of the notion of an external world, the doubt of which is meant to arise as a consequence of this radical doubt. We will return to this point. Now, one might think that understanding the external/internal distinction in play in external world scepticism is relatively straightforward. Here is Porchat: ““External world” seems immediately to oppose “internal world” and, despite the spatial connotations of these expressions, such a distinction and opposition seem to immediately refer us, if we wish to use modern terminology, to the distinction and opposition between mental and non-mental, between the human mind (whatever the expression “mind” may designate) as an “internal universe” and everything that is not part of it, that is, the reality “outside the mind”, the world.” (117) In short, the ‘internal’ is one’s inner mental life, while the ‘external’ is everything outside of that mental life, including one’s body, other people, physical objects, and so on. This has an interesting consequence, as Porchat notes, that the ‘place’ where the (methodological) doubting takes place—where one weighs up the reasons for and against the existence of an external world—must be within the inner realm: 5 “For by saying that we doubt the existence of an external reality, or that we suspend judgement on it, or that we are seeking reasons to justify our belief in it, or even just proclaiming that we have them, we are also at the same time ipso facto presupposing that, if we once again allow ourselves a spatial metaphor, the place where these various operations take place is our mind, a kind of “internal universe” that is contrasted with a world that we conceive of as “external” and entirely other than it, only in relation to which this “exteriority” is defined.” (117) The problem, however, is that this distinction is now revealed to be bringing with it a kind of epistemic priority, with the inner realm being the ‘location’ of the doubt, and the external realm as being the object of the doubt.9 Of course, Descartes ultimately wants to cast doubt on the inner realm too, but the point is that in working towards that (even) more radical form of doubt he has already bought into a philosophical picture that must give epistemic priority to the inner realm of the mind over the external realm. Here is Porchat on this point: “[…] the mind […] as what is given and not problematised, while the world, conversely, as what is not given, since it is, or can be, problematised. And the very vocabulary of exteriority already suggests such problematisation and invites it. Indeed, precisely because it presupposes¾and is opposed to¾a given “interiority”, the notion of exteriority emerges, so to speak, already fraught with problematicity, and the possibility promptly insinuates itself of questioning the reality of this “exteriority”.” (118) Porchat’s point, I take it, is that once we accept this distinction, then we have already made a deep concession to the Cartesian radical sceptical project, for the distinction itself invites scepticism about the external world by in effect treating our beliefs about this realm, in contrast to our beliefs in the inner realm, as inherently epistemically problematic. Moreover, Porchat argues that this distinction buys into a conception of the mind that is so radically opposed to our ordinary conception that it ought to at least be subject to greater critical scrutiny. We’ve already noted the point that our bodies are external to us on this conception of the internal/external distinction. But consider now what one must be referring to when one uses the pronoun ‘I’ on this conception? “[…] it also seems undeniable that, every time we express one of those procedures of problematising the existence of the “external” world, we are presupposing that the referentiality of the pronoun “I”, certainly a necessary ingredient of our linguistic formulations and used to talk about that doubt or suspension of judgement or inquiry or belief, refers primarily to our mind. Indeed, having distinguished between the mind and the body and problematised the body, it is to the former that the pronoun then immediately refers, thereby signifying the completion of a rupture between the self and the body proper. The body, which we may believe we “have”, thus appears as something other than truly our 6 self, as being part of, not this, but rather, the world that is “outside of us” and in which, for that very reason, we seem also to say that we, in some way, are not.” (118) Construing the inner realm such that our bodies are external to us thus leads to a conception of the self that is alienated from one’s own body. And yet this goes entirely against our commonsense conception of the self as embodied. We are now in a position to understand Porchat’s fundamental problem with Cartesian scepticism about the external world. This is that it represents itself as a radical form of doubt that literally has everything in its cross-hairs, and yet when we look closer at the mechanics of this form of scepticism we see that it is implicitly trading on philosophical theses that are at least controversial, but which are nonetheless not themselves subject to radical doubt. Here is Porchat: “[…] I am defending the thesis that the sceptical problematisation of the world, conceived as “external,” actually rests, despite the sceptics’ claim to have universally suspended judgement on all opinions and doctrines, on a particular philosophical option, that is, on some form of philosophy of mind, in the broadest sense that this expression can be given.” (120) If that’s right, then that dramatically undermines the plausibility of Cartesian scepticism. For one thing, the universal doubt, if applied to the contentious philosophical theses in play, would thereby undermine the very project of radical doubt. In short, the project is in danger of imploding under the contradictory pressure of its own commitments. For another, Cartesian scepticism cannot possibly present us with a paradox if it is ultimately turning on the acceptance of contentious philosophical claims that are utterly alien to our ordinary ways of thinking. The putative fundamental sceptical tension, it seems, is not within our own commonsense epistemic concepts but rather arises out of the uncritical acceptance of dubious philosophical theses. If so, then the result is not paradox, but merely the philosophical irrelevance of Cartesian scepticism. 3. THE VEIL OF PERCEPTION AND EPISTEMOLOGICAL DISJUNCTIVISM That Cartesian scepticism ultimately implicitly turns on contentious philosophical theses is these days not that controversial in contemporary epistemology (though as I remarked 7 earlier, Porchat was arguably ahead of his time in this regard). As noted above, Williams (1991) brought this idea into the philosophical mainstream with aplomb, and in the process he (independently) made many of the same critical claims that we have seen Porchat make. The first point I should make is thus my general agreement with the stance that Porchat takes in this regard. Nonetheless, I think there is something important missing from his diagnosis of where Cartesian scepticism goes awry.10 In particular, I want to suggest that Cartesian scepticism is really trading on two faulty philosophical pictures, where either one of them, if allowed, would suffice to generate the envisaged sceptical threat. If that’s right, then there are really two putative sceptical paradoxes in play (albeit overlapping sceptical paradoxes, rather than being completely distinct from each other). That means that any diagnosis of where Cartesian scepticism goes wrong that attends only to the inherent failings of just one of the underlying philosophical pictures has missed something important. Let’s begin with what I think Porchat has got right. The idea of interiority, and the associated conception of exteriority, that he has flagged is certainly highly problematic. Porchat follows most commentators in expressing this thesis in primarily metaphysical terms, in the sense that it leads to a ‘veil of perception’ that problematizes our relationship to the external world. In particular, it entails that our experiences are not directly of the world at all, but rather reside in a completely distinct ‘internal’ realm that is metaphysically disconnected from the ‘external’ world. Once that picture is in place, then it is relatively straightforward to generate the radical sceptical worry about our ability to know truths concerning this external realm. After all, if our experiences are disconnected from the external world in this way, then how can they provide us with epistemic access to it? The underlying (and dubious) metaphysical picture thus generates the negative epistemological consequences that lead to radical scepticism. While I think that is broadly correct, I would add that there is a second, more specific, veil that this faulty philosophical picture generates that is epistemic rather than metaphysical in nature. Let’s call it the ‘veil of perceptual reasons’. As I have put it elsewhere, what is being committed to here is the insularity of reasons thesis, such that it is in the nature of reasons, including our perceptual reasons, that they cannot entail truths about the world.11 In particular, the perceptual reasons one has, even in the best case scenario when one is in direct cognitive contact with reality in the general manner that one supposes, 8 cannot be any better than the reasons one has when one is in a corresponding ‘bad’ case where one is undetectably radically deceived, such as a radical sceptical scenario. The point is that the contentious philosophy of mind that leads to the metaphysical veil also generates the further epistemic veil too. But it is this latter veil, if granted, that has the most disturbing sceptical consequences, as it entails that one’s reasons must fall short of the world. Accordingly, it is now hard to see how one can have rational support for one’s beliefs about the external world. In particular, that it seems to you as if you have hands is the kind of perceptual reason that you would share with your counterpart in a radical sceptical scenario where your hands are lacking (e.g., the famous ‘brain-in-a-vat’ radical sceptical scenario), and so is allowed on this ‘insulated’ conception of reasons. But if that’s the only kind of rational basis that one can have, then what rational basis can you possibly have for thinking that you have hands rather than simply ‘vat-hands’ (i.e., merely the kind of experience of hands that someone who is envatted might have)? The answer, of course, is none at all. Radical scepticism now starts to look irresistible. Following the work of John McDowell (e.g., 1995), I’ve argued that the way to resist this sort of faulty philosophical picture that generates radical scepticism is to embrace what I call epistemological disjunctivism.12 Epistemological disjunctivism rejects this picture by making the case for the existence of factive reasons; in particular, the factive perceptual reason that one sees that p. Our ordinary language is shot-through with appeals to factive reasons. In the normal case, where there is no specific reason for doubt (one sees the target object clearly, one is not in possession of defeaters, and so on), it would be entirely natural to offer as rational support for your knowledge of what you see by saying that you can see that this is the case. Indeed, it would be very odd to qualify your rational basis by giving only the nonfactive reason that it seems to you as if this is the case, given that the conditions are good are in this manner. For example, your boss phones you up at work and is sceptical when you say that a colleague is in her office, as she assumes that this colleague takes the opportunity to be absent when she is away. Since the colleague is sitting right in front of you, wouldn’t you defend your knowledge claim by saying that you can see that she is present at the office? And wouldn’t it be odd if you instead said that it merely seems to you that she is present, as if there were some reason to doubt what you see? 9 If factive reasons are rooted in our ordinary epistemic practices in this way, then the onus is on the person who wishes to advocate for the insularity of reasons thesis, and the related veil of perceptual reasons, to offer grounds for their position. I will spare the reader the details, as they aren’t salient to our discussion, but suffice it to say that when one looks closer at the argumentative basis for the insularity of reasons, it rests on very slender considerations indeed.13 What is salient to our discussion is that epistemological disjunctivism is offering an undercutting treatment of the form of radical scepticism that trades on this faulty philosophical picture.14 That is, what looked like a bona fide paradox—i.e., whereby a genuine and fundamental tension has been exposed in our thinking in this domain—turns out to instead trade on dubious philosophical theses masquerading as commonsense. The paradox is thus undercut, as it turns out to be illusory.15 This general approach to radical scepticism should remind us of Porchat’s own strategy in this regard, as it is essentially the same. Of course, there is no definitive way of knowing whether Porchat would be happy with epistemological disjunctivism, specifically, as a way of unpicking the faulty veil of perception philosophical picture, but we can at least say that it is entirely in the spirit of his views in this regard. In particular, epistemological disjunctivism resists the metaphysical (and thus epistemic) split between the ‘internal’ and the ‘external’ world, such that our reasons end up in the former realm and thereby completely divorced from the latter realm. Instead, it offers us a conception of reasons, including perceptual reasons, such that they can be genuinely world-involving. And that’s just the kind of picture we would expect to be left with once we have rejected the contentious philosophy of mind that Porchat identifies as being in the background of external world scepticism.16 4. THE UNIVERSALITY OF RATIONAL EVALUATION AND WITTGENSTEINIAN HINGE EPISTEMOLOGY If Cartesian external world scepticism only turned on a commitment to the veil of perception and thus the associated insularity of reasons thesis, then all we would need to resolve it would be epistemological disjunctivism. Combining Porchat’s overarching diagnostic critique of external world scepticism with the more detailed critique of the 10 insularity of reasons thesis offered by epistemological disjunctivism would thus suffice to offer a satisfying undercutting response to external world scepticism. Unfortunately, matters are not quite so simple. The reason for this is that there are actually two faulty philosophical pictures in play in Cartesian scepticism. They are overlapping philosophical pictures, and so it is sometimes hard to set them apart. And yet they are ultimately distinct. Moreover, that they are ultimately distinct is philosophically important because the (undercutting) rejection of the one philosophical picture doesn’t thereby ensure that you are rid of the other philosophical picture too. The first picture, as we have seen, is associated with the veil of perception and leads to the insularity of reasons thesis. Porchat correctly identifies the importance of this philosophical picture to external world scepticism. The second picture is the idea, core to Cartesian scepticism as we noted above, that one could, in principle at least, coherently undertake rational evaluations that are universal, in the sense that they target all of one’s commitments all at once, even if only in a purely methodological spirit. It is only if this is coherent that it can be possible to undertake the project of radical, universal, doubt that Descartes envisages. Elsewhere, I have called this thesis the universality of rational evaluation thesis.17 On the face of it, this claim can seem completely harmless. Why shouldn’t one be able to extend the scope of one’s doubt without limit, to the extent that one doubts everything? Of course, there might be psychological limitations on actual doubt of this kind—something that Pyrrhonians are acutely aware of— but insofar as the doubt is purely theoretical in nature, as Descartes suggests (it is doubt in the study only, and not also doubt in the street, to paraphrase Hume), then these psychological limitations don’t gain a purchase. All that matters is that the universal doubt is coherent and then the Cartesian project is up-and-running, and on the face of it there don’t seem to be any in-principle considerations that could limit the scope of such purely theoretical doubt. And yet, as we will see, the universality of rational evaluation thesis is every bit as philosophically dubious as the insularity of reasons thesis. Although the universality of rational evaluation thesis runs alongside the veil of perception picture that underpins the very idea of an ‘external’ world, it is not the same. This point gets obscured because Descartes begins his project with the radical doubt and is thereby led to his conception of an external world that embodies the veil of perception. So one might naturally think that the latter flows directly from the former. There is certainly an 11 overlap of ideas here, in that one needs radical sceptical scenarios to motivate the veil of perception idea, and the desire to exclude those scenarios is effectively an expression of the universality of rational evaluation thesis. (We will return to this claim below). That would suggest that it is really the universality of rational evaluation thesis that is the underlying faulty philosophical picture in play here, and not the veil of perception (much less the insularity of reasons thesis). If so, then Porchat’s diagnosis of external world scepticism gets it all wrong. But that is not the conclusion that we should draw. In fact, the defective insularity of reasons thesis and the defective universality of rational evaluation thesis are able to motivate radical scepticism independently of each other (even if, in practice—as in the case of Descartes—the one is often used to motivate the other). Consider first how one might go directly from the insularity of reasons thesis to radical scepticism without first passing through the universality of rational evaluation thesis. Once one recognises the distinction between these two theses, then this task is relatively straightforward. Yes, you need to consider scenarios where one is undetectably and radically in error, but you don’t need to suppose that such scenarios generate any doubt (even of the methodological kind). All you need is the very fact that such scenarios exist and can be used to generate the thought that one’s reasons must be common to both the ‘good’ case where everything is fine and the ‘bad’ case where one is undetectably deceived. That suffices to ensure that the veil of perceptual reasons has fallen, and radical scepticism will now start to look irresistible.18 Going in the other direction, one can motivate radical scepticism by appeal to the universality of rational evaluation thesis without in the process appealing to the insularity of reasons thesis. This is, in fact, exactly what contemporary formulations of radical scepticism in terms of what is known as the ‘closure’ principle do. The idea behind such a closure principle is that if one undertakes a competent deduction from one’s knowledge, and forms a belief on this basis, then one thereby has knowledge of the deduced proposition.19 So construed, the principle looks utterly anodyne. If I know that Paris is the capital of France, and I thereby competently deduce that Madrid is not the capital of France, then surely I can come to know the deduced proposition. The radical sceptical import of this principle is that much of our everyday knowledge entails the denials of radical sceptical hypotheses. Accordingly, it should be the case that we can come to know these denials via closure-style inferences from our everyday knowledge. If 12 I know that I am in California, for example, then using this principle I can come to know that I am not a brain-in-vat on Alpha Centauri. Conversely, however, once it is granted (as it usually is) that it is impossible to know the denials of radical sceptical hypotheses, then it follows, via closure, that we can’t possibly have the everyday knowledge either. In short, because I can’t know that I’m not a brain-in-a-vat on Alpha Centauri, it follows that I cannot know that I am in California either. And what goes for this everyday claim will apply to a wide range of one’s beliefs (one just needs to vary the radical sceptical scenario in play to generate the target result). As we will see in a moment, one needs to have the universality of rational evaluation thesis in the background in order to use the closure principle in this way to generate radical scepticism. Notice, however, that there is no appeal here to the insularity of reasons thesis, much less is there any metaphysical claim about the veil of perception. In particular, there is no claim being made that one’s rational support is the same regardless of whether one is in the good case or the radical sceptical bad case. All that is required to motivate the argument is that one is unable to know that one is not the victim of a radical sceptical argument.20 Accordingly, if one tried to diagnose what is driving this type of sceptical argument by appealing to the veil of perception, then one would be missing the target. For the same reason, it would not be very wise to try to resolve this form of radical scepticism by appealing to epistemological disjunctivism; for example by arguing that we can know the denials of radical sceptical scenarios after all, via closure-style inferences from our everyday perceptual knowledge that is supported by factive reasons.21 That one can have factive reasons in support of one’s knowledge is one thing; that one can legitimately employ those factive reasons to come to know that one is not the victim of a wholesale—and by definition undetectable—deception is something altogether different. So what then is the right way to respond to closure-based radical scepticism? I think the answer lies in Wittgenstein’s fascinating final notebooks, published posthumously as On Certainty.22 Wittgenstein’s overarching goal in these notebooks is to demonstrate the incoherence of the universality of rational evaluation thesis. In particular, he argues that once we understand the structure of rational evaluation properly, then we realise that the very idea of universal rational evaluations—even of the Cartesian methodological kind—is simply incoherent. This is an undercutting response to this form of radical scepticism, as it proceeds by showing that the putative radical sceptical paradox (in our terminology, the closure-based 13 version) is treating a contentious philosophical thesis (the universality of rational evaluation thesis) as if it were part of our natural ways of thinking within this domain. Once the contentious philosophical thesis is removed, however, the putative paradox is revealed as illusory. Wittgenstein achieves this result by showing how what it means to be a rational subject at all—someone who makes moves within the space of reasons; who doubts, believes, offers reasons, and so on¾is to have an overarching certainty in the veracity of one’s worldview. It is only if this certainty is in place—a certainty that is rooted in action rather than reasons—that one is able to even acquire a worldview in the first place. It follows that this overarching certainty cannot be itself rationally grounded, as it is what needs to be in place in order for rational evaluations to take place.23 It is thus essentially arational. Intriguingly, Wittgenstein further argues that this overarching certainty in one’s worldview manifests itself in a complete certainty in specific commonsense claims, such as that one has hands (OC, §1), what one’s name is (OC, §425), and the language that one is speaking (OC, §158). The idea is that such commonsense certainties reflect the overarching certainty in the worldview because doubt here would ‘drag everything with it and plunge it into chaos.’ (OC, §613) That is, to doubt these everyday commonsense certainties is effectively to thereby doubt the overarching certainty in the worldview, and that’s why they inherent the properties of the overarching certainty. In particular, they are part of the arational framework against which rational evaluation takes place. These framework arational certainties are these days known as a hinge commitments, following a metaphor used by Wittgenstein. (OC, §341-44) 24 In the same vein, I refer to the overarching certainty one has in the general veracity of one’s worldview as the über hinge commitment. 25 Since one’s hinge commitments are essentially arational, they are also thereby unknown. Notice, however, that it is not as if one’s hinge commitments are unknown in the sense that one is ignorant of them. The point is rather that it is in the nature of hinge commitments that they are not in the market for knowledge. That one fails to know one’s hinge commitments does not therefore reveal a cognitive deficiency on one’s part. Indeed, one is no more cognitively deficient for failing to know one’s hinge commitments than one is lacking in imaginative capacity in being unable to conceive of a circle-square.26 14 Naturally, this is not the place to mount a full defence of the Wittgensteinian conception of hinge commitments.27 My point is rather that Wittgenstein is engaging with the specific version of the radical sceptical problematic that presently concerns us. For if it is in the very nature of what is to be a rational subject that one has arational hinge commitments, then the very idea of universal rational evaluations is simply incoherent. It is, instead, a dubious philosophical thesis masquerading as commonsense. Accordingly, this version of the radical sceptical ‘paradox’ is shown to be illusory. Notice, however, that Wittgenstein is not responding to this form of radical scepticism by claiming that we do know the denials of radical sceptical scenarios. The point is rather that we should resist the idea that in order to have rationally grounded everyday knowledge that we must be able to also know the denials of radical sceptical hypotheses. To know the denials of radical sceptical scenarios would, after all, involve a fully general rational evaluation of our commitments, as it would require reasons for thinking that our worldview is not fundamentally in error. In short, it would involve gaining rational support for the über hinge commitment, which as we have seen is impossible. Rational evaluation is rather by its nature local. This means that the fact that we are unable to know the denials of radical sceptical scenarios doesn’t impact on our knowledge of everyday claims.28 What is significant for our purposes is that this undercutting treatment of the aspect of radical scepticism that turns on the universality of reasons thesis is entirely independent of the undercutting treatment of the aspect of radical scepticism that turns on the insularity of reasons thesis. In fact, one can see this point in action by simply reflecting that neither diagnosis entails the other. Perhaps rational evaluations are by their nature local and yet perceptual reasons are nonetheless insular? Nothing in the former excludes the latter. Going in the other direction, perhaps perceptual reasons can be factive and yet universal rational evaluations are entirely coherent? Again, nothing in the former excludes the latter. The crux of the matter is that just as we have two distinct motivations for radical scepticism in play here, so we have two distinct diagnostic treatments of this problem. If we want to fully undercut the problem posed by radical scepticism, then it is imperative that we attend to both of its aspects. Would Porchat have been amenable to Wittgensteinian hinge epistemology, and in particular to this distinction between the two sources of radical scepticism? Unlike epistemological disjunctivism, the answer is ‘probably not’. For one thing, it seems clear that 15 he regards the metaphysical diagnosis he offers of external world scepticism in terms of the veil of perception as being fundamental. But there is also a second reason to think he would be resistant to this Wittgensteinian picture, which is his critical remarks on what he terms ‘justificationism’ in his ‘Common Knowledge and Scepticism’ (Porchat 1986a), which was written around the same time as ‘Scepticism and the External World’ (Porchat 1986b). Justificationism is, roughly, the idea that knowledge should be supported by justification— i.e., should be underpinned by reasons. Porchat rejects such a view, arguing that allowing that there can be bona fide knowledge that is not rationally supported is a key move in resisting radical scepticism. I think that this is a mistake, as it involves making a major concession to radical scepticism that is not required, as Wittgenstein shows.29 For if Wittgenstein is right that it is in the nature of rational evaluation that it turns on a framework of arational certainty, then it follows that not all of our commitments could be rationally grounded. But the proper conclusion to draw from this is not to concede that some of our knowledge is not rationally grounded, but rather to embrace the fact that one inevitably has some fundamental commitments that are not in the market for knowledge at all. As Wittgenstein demonstrates, while this can initially look like a concession to radical scepticism, it is in fact a key part of what is required to resist the philosophical picture that radical scepticism turns on, whereby universal rational evaluations (whether negative, in the case of radical scepticism, or positive, in the case of tradition anti-sceptical arguments) are coherent.30 At any rate, even if Porchat would not endorse this two-pronged diagnosis of radical scepticism, I think we can be confident that he would embrace the style of anti-scepticism that it represents, whereby we unpick the sceptical problematic by showing how it turns on contentious philosophical claims masquerading as commonsense.31 16 REFERENCES Barnes, J. (1982). ‘The Beliefs of a Pyrrhonist’, Proceedings of the Cambridge Philological Society 208, 1-29. Burnyeat, M. (1980). ‘Can the Skeptic Live his Skepticism?’, Doubt and Dogmatism: Studies in Hellenistic Epistemology, (eds.) J. Barnes, M. Burnyeat & M. Schofield, ch. 3, Oxford: Clarendon Press. ¾¾ (1982). ‘Idealism and Greek Philosophy: What Descartes Saw and Berkeley Missed,’ Philosophical Review 91, 3-40. Cassam, Q. (2007). The Possibility of Knowledge, Oxford: Oxford University Press. Coliva, A. (2015). Extended Rationality: A Hinge Epistemology, London: Palgrave Macmillan. —— (2022). Wittgenstein Rehinged, London: Anthem. Fine, G. (2021). Essays in Ancient Epistemology, Oxford: Oxford University Press. Fogelin, (1994). Pyrrhonian Reflections on Knowledge and Justification, Oxford: Oxford University Press. Frede, M. (1984). ‘The Sceptic’s Two Kinds of Assent and the Question of the Possibility of Knowledge’, Philosophy in History: Essays on the Historiography of Philosophy, (eds.) R. Rorty, J. B. Schneewind & Q. Skinner, ch. 11, Cambridge: Cambridge University Press. McDowell, J. (1995). ‘Knowledge and the Internal’, Philosophy and Phenomenological Research 55, 877-93. McGinn, M. (1989). Sense and Certainty: A Dissolution of Scepticism, Blackwell, Oxford. Moyal-Sharrock, D. (2004). Understanding Wittgenstein’s On Certainty, London: Palgrave Macmillan. Moyal-Sharrock, D., & Pritchard, D. H. (2024). Wittgenstein on Knowledge and Certainty, Cambridge: Cambridge University Press. Porchat, O. P. (1986a). ‘Common Knowledge and Scepticism’, Manuscrito 9, 143-59. ¾¾ (1986b). ‘Scepticism and the External World’, Analysis 4, 75-109. ¾¾ (1987a). ‘Common Knowledge and Scepticism’, Crítica 1, 57-77. ¾¾ (1987b). ‘Scepticism and the External World’, Discourse 16, 33-68. ¾¾ (1991). ‘On What Appears’, Revista Latinoamericana de Filosofía 17, 195-229. ¾¾ (1993). Vida Comum e Ceticismo (Common Life and Scepticism), São Paulo, Brazil: Editora Brasiliense. ¾¾ (2003). ‘The Madness Argument’, Manuscrito 26, 11-43. Pritchard, D. H. (2005). ‘The Structure of Sceptical Arguments’, Philosophical Quarterly 55, 37-52. ¾¾ (2012). Epistemological Disjunctivism, Oxford: Oxford University Press. ¾¾ (2015). Epistemic Angst: Radical Skepticism and the Groundlessness of Our Believing, Princeton, NJ: Princeton University Press. —— (2017). ‘Wittgenstein on Hinge Commitments and Radical Scepticism in On Certainty’, Blackwell Companion to Wittgenstein, (eds.) H.-J. Glock & J. Hyman, 563-75, Oxford: Blackwell. ¾¾ (2018a). ‘Epistemic Angst’, Philosophy and Phenomenological Research 96, 70-90. ¾¾ (2018b). ‘Unnatural Doubts’, Skepticism: Historical and Contemporary Inquiries, (eds.) G. A. Bruno & A. Rutherford, 223-47, London: Routledge. ¾¾ (2021a). ‘Ignorance and Inquiry’, American Philosophical Quarterly 58, 111-23. ¾¾ (2021b). ‘Ignorance and Normativity’, Philosophical Topics 49, 225-43. 17 (2022). ‘Hinge Commitments and Common Knowledge’, Synthese, [Online First, DOI: 10.1007/s11229-022-03647-5]. ¾¾ (2023). ‘In Defence of Closure’, New Perspectives on Epistemic Closure, (eds.) M. Jope & D. H. Pritchard, 113-30, London: Routledge. ¾¾ (2024). ‘Beliefs, Delusions, Hinge Commitments’, Synthese [DOI: https://doi.org/10.1007/s11229-024-04703-y]. Ribeiro, B. (2002). ‘Is Pyrrhonism Psychologically Possible?’, Ancient Philosophy 22, 319-31. Schönbaumsfeld, G. (2016). The Illusion of Doubt, Oxford: Oxford University Press. Stough, C. (1984). ‘Sextus Empiricus on Non-Assertion’, Phronesis 29, 137-64. Strawson, P. F. (1985). Skepticism and Naturalism: Some Varieties, New York: Columbia University Press. Stroll, A. (1994). Moore and Wittgenstein on Certainty, Oxford: Oxford University Press. Stroud, B. (1984). The Significance of Philosophical Scepticism, Oxford: Clarendon Press. Vogt, K. (2015). ‘Why Ancient Skeptics Don’t Doubt the Existence of the External World: Augustine and the Beginnings of Modern Skepticism’, Roman Reflections: Studies in Latin Philosophy, (eds.) G. D. Williams & K. Volk, ch. 13, Oxford: Oxford University Press. Williams, M. (1988). ‘Scepticism Without Theory’, Review of Metaphysics 41, 547–88. ¾¾ (1991). Unnatural Doubts: Epistemological Realism and the Basis of Scepticism, Oxford: Blackwell. Williamson, T. (2000). Knowledge and its Limits, Oxford: Oxford University Press. Wittgenstein, L. (1969). On Certainty (=OC), (eds.) G. E. M. Anscombe & G. H. von Wright, (trans.) D. Paul & G. E. M. Anscombe, Oxford: Blackwell. Wright, C. J. G. (2004). ‘Warrant for Nothing (and Foundations for Free)?’, Proceedings of the Aristotelian Society (supp. vol.) 78, 167-212. ¾¾ 18 NOTES This was originally published as Porchat (1986b). See also Porchat (1987b; 1993, 12-65). It is reproduced in this volume as chapter 6. The reader should also consider Porchat’s ‘Common Knowledge and Scepticism’ (reproduced in this volume as chapter 5), which was written around the same time as ‘Scepticism and the External World’, and hence contains some overlapping ideas. This paper was originally published as Porchat (1986a) and subsequently reprinted Porchat (1987a; 1993). 2 Plino Smith has pointed out to me that Porchat was ahead of his time in other respects too. For example, he anticipates the neo-Pyrrhonism of Fogelin (1994) with his own formulation of this stance, which first appears in Porchat (1991). (This paper is reprinted as chapter 7 in this volume). 3 The exception to this—as noted in endnote 1—is ‘Common Knowledge and Scepticism’ (Porchat 1986a), which was written around the same time as ‘Scepticism and the External World’ (Porchat 1986b), and which contains some similar themes. See also endnote 16. 4 All page numbers refer to the version of Porchat’s works that feature in this volume. 5 See also this passage: “The “methodological suspension of judgement on the external world” has become something like the basic and indisputable axiom of philosophical methodology to which I referred at the beginning. And, in this way, methodological scepticism has become an omnipresent paradigm, sometimes a hidden paradigm, but always at least presupposed. And presupposed in complete ignorance of its origins, as if it were not the historical result of a particular philosophical stance, built on a very particular style of argumentation.” (111) 6 For some useful discussions of the ‘liveability’ of Pyrrhonian scepticism, see Burnyeat (1980), Barnes (1982), Frede (1984), Stough (1984), Williams (1988), and Ribeiro (2002). 7 For some useful discussions on the contrasts between Pyrrhonian and Cartesian scepticism, see Burnyeat (1982), Williams (1988), Vogt (2015), and Fine (2021, ch. 13). Intriguingly, Porchat rejects the popular view that early modern scepticism is fundamentally different to ancient Greek scepticism. Indeed, he argues that the basic ideas behind the ‘veil of perception’ that come to the fore in the early modern period in the works of empiricist philosophers like Locke can also be found in ancient Greek sceptical thought. See, for example, his critical discussion of Rorty (130 & ff.). 8 For an important contemporary text that made this idea of radical scepticism as a paradox particularly vivid, see Stroud (1984). See also Williams (1991). 9 This point about epistemic priority in the context of external world scepticism is also one of the animating themes in Williams (1991). 10 Although I cannot get into this here, this lacuna is also present in Williams (1991). See Pritchard (2018c). 11 See, especially, Pritchard (2015, passim). 12 See, especially, Pritchard (2012; 2015, part 3). 13 If the reader wants the fuller story, then they should consult Pritchard (2012, passim; 2015, part 3). 14 For discussion of undercutting treatments of putative paradoxes, see Pritchard (2015, part 1). For discussion of related notions as applied to our thinking about putative (radical sceptical) paradoxes, see Williams (1991, ch. 1) and Cassam (2007, passim). See also endnote 15. 15 Compare an overriding response to a radical sceptical paradox. This would involve granting that it is a genuine paradox—i.e., that there really is a fundamental tension in our ordinary ways of thinking within the relevant domain being exposed by the radical sceptic¾but which contends, nonetheless, that there are independent grounds to reject one of the horns of the paradox. See also the references in endnote 14. 16 In his very helpful comments on an earlier version of this paper, Plino Smith¾who is, of course, an expert on Porchat’s work¾agreed that Porchat would likely be inclined to endorse epistemological disjunctivism, had he ever encountered it. He did note a caveat in this regard, however, which is the remarks that Porchat makes in the ‘sister’ paper to ‘Scepticism and the External World’, which is ‘Common Knowledge and Scepticism’ (see endnote 1). For in that work Porchat offers the intriguing suggestion that part of the response to radical scepticism should be to resist the idea that knowledge always requires justification, and thus rational support. With that in mind, it isn’t entirely clear that Porchat would be willing accept that perceptual knowledge, even in paradigmatic cases, is always rationally supported, whether by factive reasons or otherwise. My own view here is that ‘Common Knowledge and Scepticism’ makes a philosophical misstep in this regard that is not present in ‘Scepticism and the External World’ (which is why the latter paper is the more interesting philosophical work). Granting that knowledge can be had outside of the space of reasons is a considerable concession to radical scepticism, particularly if, as Porchat’s ‘Scepticism and the External World’ ably demonstrates, this form of radical scepticism trades on dubious metaphysical claims that we would be wise to reject out of hand. Far better, then, to keep knowledge within the space of reasons and meet the radical sceptical challenge headon, without making such far-reaching concessions. 1 19 See, especially, Pritchard (2015, passim). In Pritchard (2015, part 1) I call this way of arguing for radical scepticism underdetermination-based radical scepticism, as it makes essential appeal to what is known in epistemology as an underdetermination principle (as opposed to the closure principle that we are about to encounter). 19 Strictly speaking¾since this is a diachronic rather than a synchronic epistemic principle¾one also needs to add that one retains one’s knowledge of the entailing proposition throughout the competent deduction (though I take it that this is implied). For an early defence of this way of thinking about closure as a competent deduction principle (this principle had previously been understood in a much cruder fashion), see Williamson (2000, 117). For further articulation and defence of this epistemic principle, see Pritchard (2023). 20 Of course, one reason one might offer to explain why one cannot know the denials of radical sceptical hypotheses would appeal to the insularity of reasons thesis. The point, however, is that we don’t need to appeal to this thesis in order to explain this claim. Indeed, as we will see in a moment, it can be true that we are unable to know the denials of radical scepticism without this involving any claim at all about the insularity of reasons (or related claims about the veil of perception). For further defence of the idea that Cartesian radical scepticism is in fact ultimately two distinct radical sceptical arguments, see Pritchard (2005; 2015, part 1). 21 Note that I am not suggesting that this style of anti-scepticism is not to some extent defensible—indeed, I explore its merits in Pritchard (2012). My point is rather that it isn’t getting to the heart of the matter. What we need instead is what I term a ‘biscopic’ resolution of radical scepticism, one that reflects its dual nature. See Pritchard (2015) for details. (See Pritchard (2018) for the short version). 22 Wittgenstein (1969). Henceforth, ‘OC’. 23 Wittgenstein describes this as a visceral kind of certainty, one that is “animal”, “primitive.” (E.g., OC §395, §475) Relatedly, he also emphasises the primacy of action in this regard, approvingly quoting Goethe in this respect: “In the beginning was the deed.” (OC §396) 24 With the corresponding epistemology known as hinge epistemology. Naturally, the version of hinge epistemology that I offer here is my own. For some of the key texts on hinge epistemology, see Strawson (1985), McGinn (1989), Williams (1991), Stroll (1994), Moyal-Sharrock (2004; 2021), Wright (2004), Coliva (2015; 2022), and Schönbaumsfeld (2016). For my own views in this regard, see Pritchard (2015, passim; 2018b). For a recent survey of this literature, see Pritchard (2017) and Moyal-Sharrock & Pritchard (2024). 25 See Pritchard (2015, part 2). 26 I argue for the particular conception of ignorance in play here—such that ignorance is not merely lack of knowledge but rather has a normative element (roughly, that one fails to be aware of something that one ought to be aware of)—in Pritchard (2021a; 2021b). 27 If one wants to read the full defence, see Pritchard (2015, passim). See also Moyal-Sharrock & Pritchard (2024, part 2). 28 Note that this doesn’t mean that the closure principle is at fault in this formulation of the putative radical sceptical paradox. The point is rather that the closure principle doesn’t have application to our commitments to hinge commitments. In brief, this is because this principle concerns the acquisition of what I term knowledge-apt (or ‘K-apt’ for short) beliefs on the basis of competent deductions, and our hinge commitments, while beliefs in the folk sense, are not K-apt beliefs. See Pritchard (2015, part 2; 2024). 29 See also my related comments in endnote 16. 30 If one ignores my exegetical caveat in the opening remarks, and thereby considers Porchat’s work as a whole, then there is a third reason to think that he would reject Wittgensteinian hinge epistemology. This is that in a late work, ‘The Argument from Madness’ (Porchat 2003, and reprinted as chapter 14 in this volume), Porchat actually endorses a kind of Cartesian universal doubt. I am grateful to Plino Smith for alerting me to this point. 31 I am extremely grateful to Plino Smith for very detailed and useful comments on an earlier version. This paper was written while a Senior Research Associate of the African Centre for Epistemology and Philosophy of Science at the University of Johannesburg. 17 18