teorema Vol. XXXVI/2, 2017, pp. 19-30 ISSN: 0210-1602 [BIBLID 0210-1602 (2017) 36:2; pp. 19-30] 19 Another Failed Refutation of Scepticism Tom Stoneham and Ema Sullivan-Bissett RESUMEN Recientemente, Jessica Wilson ha elaborado una versión más sofisticada de la objeción según la cual el escepticismo cartesiano se auto-destruye. Wilson defiende que afirmar el escepticismo cartesiano conduce a un regreso vicioso imparable. La manera de evitarlo es no seguirle el juego al escéptico cartesiano, detener el regreso desde el principio, tras la aseveración garantizada de que hay un mundo externo. Aquí ofrecemos tres razones para decir que la objeción no funciona: primero, el escéptico no tiene por qué aceptar la caracterización de la tesis escéptica que da Wilson, con lo que no tiene por qué embarcarse en un regreso; segundo, incluso si el escéptico se comprometiera con un regreso, ello no socavaría el escepticismo de la manera que Wilson piensa; y tercero, el recurso al escepticismo sobre los estados mentales, que es necesario para generar los pasos segundo y sucesivos del regreso, no está justificado. PALABRAS CLAVE: escepticismo cartesiano, objeción de la auto-destrucción, escepticismo sobre los estados mentales. ABSTRACT Jessica Wilson has recently offered a more sophisticated version of the self-defeat objection to Cartesian scepticism. She argues that the assertion of Cartesian scepticism results in an unstable vicious regress. The way out of the regress is to not engage with the Cartesian sceptic at all, to stop the regress before it starts, at the warranted assertion that the external world exists. We offer three reasons why this objection fails: first, the sceptic need not accept Wilson's characterization of the sceptical thesis and thus need not start her regress; second, even if she did commit to the regress, it would not undermine scepticism in the way Wilson envisages; and third, the appeal to mental state scepticism which is necessary to generate the second and subsequent steps in the regress is not justified. KEYWORDS: Cartesian Scepticism; Self-defeat Objection; Mental State Scepticism. INTRODUCTION The Cartesian sceptic argues that we cannot, and therefore do not, know anything.1 A simplistic response is to say that this is self-defeating: 20 Tom Stoneham and Ema Sullivan-Bissett teorema Vol. XXXVI/2, 2017, pp. 19-30 either you know the sceptical claim and thus know something, rendering it false, or you do not know it and thus we have been given no reason to give up our dogmatism. The natural response to such an objection is to limit the scope of the sceptical claim to knowledge of the external world. This is usually done by showing that the sceptical argument, drawing upon the possibility that we are undetectably deceived about the external world, has this limitation built in. In slogan form: sceptical scenarios do not undermine our ability to know the sceptical claim.2 Jessica Wilson has recently offered a more sophisticated version of the self-defeat objection. She argues that the assertion of Cartesian scepticism results in an unstable vicious regress. The way out of the regress is to not engage with the Cartesian sceptic at all, to stop the regress before it starts, at the warranted assertion that the external world exists. In this short paper we offer three reasons why this objection fails: firstly, the sceptic need not accept Wilson's characterization of the sceptical thesis and thus need not start her regress; secondly, even if she did commit to the regress, it would not undermine scepticism in the way Wilson envisages; and thirdly, the appeal to mental state scepticism which is necessary to generate the second and subsequent steps in the regress is not justified. I. WILSON'S REGRESS Wilson begins by asking whether the external world exists, 'as it so concretely seems' [Wilson (2012), p. 668]. Perhaps not, she goes on, for the Cartesian sceptic says that we might be systematically deceived by an evil demon, or be brains in vats, in which case everything would seem to us exactly as it does seem, whilst all of our beliefs about the external world would be false. Before I meet the sceptic, I warrantedly assert that the external world exists. Then, I read Descartes' first Meditation and I come to have a sceptical attitude towards the truth of the proposition that the external world exists. Now all I can warrantedly assert is the claim that I am sceptical whether3 the external world exists: I cannot warrantedly assert that the external world does exist, nor can I warrantedly assert that the external world does not exist. This is the position of Wilson's Cartesian sceptic. Next I meet the mental state sceptic and she makes the same move as made by the Cartesian sceptic, she casts doubt on the warranted assertability of my current claim - the claim that I am sceptical whether the external world exists. So I come to have a sceptical attitude towards whether I have a sceptical attitude towards the proposition that the external world exists, and all I can warrantedly Another Failed Refutation of Scepticism 21 teorema Vol. XXXVI/2, 2017, pp. 19-30 assert is the claim that I am sceptical whether I am sceptical whether the external world exists, I cannot assert that I am sceptical whether the external world exists, nor can I assert that I am not sceptical whether the external world exists. The idea is that if by contemplation of Cartesian scenarios, I am moved to scepticism about the truth of the proposition that the external world exists, then via that same contemplation, I ought also to be moved to scepticism about whether I am sceptical whether the external world exists. But why stop there? Now the mental state sceptic mounts the same attack on my new assertion, and so it goes on, ad infinitum: To start: A (the external world exists) At step 1 (after my encounter with the external world skeptic): A (S (the external world exists)) and Not-A (the external world exists) and Not-A (not-the external world exists) At step 2 (after my encounter with the mental state skeptic): A (S (S (the external world exists))) and Not-A (S (the external world exists)) and Not-A (not-S (the external world exists)) At step 3 (after another encounter with the mental state skeptic): A (S (S (S (the external world exists)))) and Not-A (S (S (the external world exists))) and Not-A (not-S (S (the external world exists))) [Wilson (2012), p. 670] What is to be done? Well, Wilson claims that the regress is 'psychologically vicious – it is rationally confounding – and so it must be stopped' [Wilson (2012), p. 671]. She also claims that the stopping place we suggest must be a principled one ('we cannot just draw the line at the 39th step' [Wilson (2012), p. 671]). As an aside, we wonder why we could not draw the line at the 39th step? This does not need to be arbitrary: perhaps it is impossible for humans to understand claims with more than a certain level of iterated logical operators, and this hits at the 39th step. If that were right, we would have the principled stopping place Wilson desires. The suggestion here is not that this is right, that humans really are 22 Tom Stoneham and Ema Sullivan-Bissett teorema Vol. XXXVI/2, 2017, pp. 19-30 only able to understand up to 39 iterations, much more would need to be said to make that claim remotely plausible. Rather our point is that there might be a step at which humans are unable to understand, and if this step were identifiable, this would provide a stopping place just as principled as Wilson's but which comes later than the one she recommends. Thus a stopping point after the first step need not be arbitrary. However, we disagree with the claim that an assertion of the Cartesian sceptic's position starts one on this regress. Rather, the Cartesian need not assert the problematic first step that supposedly makes her position objectionable. Second, even if Wilson is right about the first step, the sceptic should not treat the resulting regress as an objection. Third, Wilson has not made the case that Cartesian scepticism about mental states is coherent and there are reasons to deny that it is, so the regress might even be stopped at the second step. We detail these three lines of response in the next three sections. II. AVOID THE REGRESS: ASSERT WHAT YOU DO NOT KNOW Wilson claims that 'as a result of contemplation of the Cartesian scenarios', one might become sceptical about whether the external world exists [Wilson (2012), p. 668]. I am a Cartesian sceptic, and I assert that I am sceptical whether the external world exists, where being sceptical whether p consists in having a distinctive propositional attitude towards p (presumably one which is inconsistent with both believing p and believing not-p). This is bad news since this assertion leads to a rationally confounding, vicious, unstable regress. So here is the first option for the Cartesian sceptic: state your position without asserting that [you are] sceptical whether the external world exists. We take it that this is not an ad-hoc patch, rather, the conclusion of the Cartesian sceptic's argument is not that one ought to be sceptical about the external world existing, it is that one cannot know whether the external world exists (or some ordinary knowledge proposition which entails the external world existing). If the argument is sound and the premises known, then the Cartesian sceptic knows that she cannot know whether the external world exists.4 While concentrating on another issue in a footnote, Wilson nicely makes the obverse of the move we are making: Another Failed Refutation of Scepticism 23 teorema Vol. XXXVI/2, 2017, pp. 19-30 The distinction between Cartesian and Pyrrhonian scepticism is often more specifically posed in terms of knowledge or some other 'pro-attitude' required for knowledge (such that, e.g., the Cartesian skeptic maintains, while the Pyrrhonian skeptic denies, that we can know that we cannot know whether the external world exists). In order to remain neutral about what epistemic state is at issue in the meta-level claim, I couch the distinction in terms of the warranted assertability (or not) of scepticism about the objectlevel claim [Wilson (2012), p. 670, fn. 7]. Here the phrase 'scepticism about the object-level claim' must refer to 'that we cannot know whether the external world exists', which is exactly what we think the Cartesian should be claiming, not that she is in the mental state of doubting whether the external world exists.5 For the sake of exposition, we will say that the Cartesian sceptic's position is that I know that I do not know whether the external world exists (rather than I cannot know). Since my being unable to know whether p entails my not knowing whether p, we think this move is permissible. Let us then start afresh with what the Cartesian sceptic is really committed to, and see how an alternative regress based on this might work. To start: A (the external world exists) This is my position before I engage with the Cartesian sceptic, I warrantedly assert that the external world exists, presumably on the basis of my perceptual evidence. After I engage with the Cartesian sceptic, I move to the claim that I do not know whether the external world exists. This is the position of the Cartesian sceptic. At step 1 (after my encounter with the external world sceptic): A (~K (the external world exists)) Note that, as a result of engaging with the Cartesian sceptic, I can move to step 1 without asserting that I am sceptical whether the external world exists. I am not asserting that I have a mental state of scepticism but that whatever mental states I have do not constitute knowledge. Now let us try to start an equivalent regress. The former regress got started via the claim that any reasons one has for moving from the first line to step 1, should also function as reasons for one moving from step 1 to step 2, so the conclusion at step 2 should have the same form. Thus: 24 Tom Stoneham and Ema Sullivan-Bissett teorema Vol. XXXVI/2, 2017, pp. 19-30 At step 2 (after my encounter with the mental state sceptic): A (~K (~K (the external world exists))) At step 3 (after my second encounter with the mental state sceptic): A (~K (~K (~K (the external world exists)))) At step 4 (after my third encounter with the mental state sceptic): A (~K (~K (~K (~K (the external world exists))))) Is this 'an unstable iteration of psychological attitudes' [Wilson (2012), p. 671]? Surely not. At step 1 I certainly no longer assert what I asserted previously, but nor do I assert its negation. Instead I assert a different proposition, namely that I do not know what I previously asserted, and similarly for each further step. This looks like the defeasibility of warranted assertability in action. Consider an analogy: We consider some data and assert theory A. Then we consider some more data and no longer assert A but instead assert (incompatible) theory B. Then we consider some more data and no longer assert B but instead assert (incompatible) theory C. And thus does science progress. The apparent instability that Wilson perceives comes from framing each sceptical claim as the positive assertion that I possess certain mental states, namely sceptical attitudes. That does seem to lead to all sorts of muddles which it might be good to stop. But in fact, at each step what the sceptic concludes, and thus asserts, is merely a negative claim about the epistemic status of what came before: it is not known. III. EMBRACE THE REGRESS: IT NEED NOT BE STOPPED In this section we suggest that should the Cartesian sceptic wish to assert that she is sceptical whether the external world exists, and granting to Wilson that that starts a vicious regress, this does not constitute an objection to such a sceptic. Let us grant to Wilson that at step 1, having engaged with the Cartesian sceptic, my position is now that I am sceptical whether the external world exists. Let us also grant that this assertion results in a rationally confounding regress. I realise that the sequence is unbounded and I will not be able to reach a stable belief. Here is our first point about this: my being unable to reach a stable belief is only an objection to the Cartesian Another Failed Refutation of Scepticism 25 teorema Vol. XXXVI/2, 2017, pp. 19-30 sceptic if what she is up to is trying to persuade me to accept a theory. But, as we saw in section two, the Cartesian is only trying to tell me that I cannot (and so do not) have knowledge whether the external world exists (and, if you allow the move to mental state scepticism, that I cannot (and so do not) have knowledge of the mental state I am in). So we learn from Wilson that claiming that I am sceptical whether the external world exists means that I cannot have a stable belief system. But that point does not undermine the Cartesian sceptic's claim that knowledge of a certain sort is impossible! To be sure, the consequence of engaging with the Cartesian sceptic and moving to the first step is psychologically disastrous. But that is acceptable for the sceptic: if it turns out that there is no stable position of scepticism, so what? There is no stable position of non-scepticism either, because the sceptic can still argue that the move to the first step is rationally required. So, even if we grant for the sake of argument that the sceptic's end place is the claim that I am sceptical whether the external world exists, and we grant that this leads the sceptic into a regress, thus undermining the warrant of her conclusion, this is not yet an objection to the sceptic's position. We see no reason why the sceptic would not simply throw up her hands and say 'OK, there is no warranted position of scepticism, but there is no warranted position of non-scepticism either! Contemplation of the sceptical scenario made I know whether the external world exists unassertable. Now I learn that so too is the claim that I am sceptical whether the external world exists. That clearly does not help the non-sceptic, the path to madness has already begun'.6 Why think that all vicious regresses should be stopped, that the sight of an impending regress should lead us to reject the argument for the first step? One might be persuaded that it is desirable that vicious regresses are stopped, but it is only the case that they rationally ought to be stopped if they violate some norm of reasoning, such as the principle of non-contradiction. The reason for blocking an argument which commits us to contradictions is a logical rule, whereas the reason (if we have one) for blocking Wilson's regress is psychological: it is confounding of our ability to reason. This means that any reason for stopping before step 1 is merely pragmatic. We do not see how something's being rationally confounding is supposed to gain traction with the Cartesian sceptic. At most, it seems to us, Wilson has shown that scepticism leads to madness, a regress of unstable attitudes, but this is a far cry from showing that Cartesian scepticism is wrong. It shows only that we have pragmatic reasons to pretend 26 Tom Stoneham and Ema Sullivan-Bissett teorema Vol. XXXVI/2, 2017, pp. 19-30 we can refute the Cartesian sceptic, even though we cannot. Perhaps if one's objective was not to refute the sceptic but merely to find adequate grounds within one's rational practices to continue with such practices despite the sceptical arguments, then this would suffice.7 But then, contrary to its advertisement, Wilson's regress would not be an argument against scepticism but an argument for dogmatism as usual. IV. BLOCK THE REGRESS: REJECT SCEPTICISM ABOUT MENTAL STATES In the preceding two sections we have argued that the regress is not threatening to Cartesian scepticism, firstly by showing that the Cartesian sceptic should not accept the formulation of step 1 in terms of a state of doubting and that when correctly formulated, the resulting regress is not vicious, and then by showing that even if she did accept step 1, the vicious nature of the regress would not undermine scepticism but support it. We now turn to step 2 and show that the appeal to sceptical scenarios at this stage does not achieve the mental state scepticism Wilson requires. Wilson takes the application of sceptical scenarios to one's mental states to be obvious and suggests that Descartes himself accepted the possibility of mental state scepticism. She provides the following two quotations to support this interpretation of Descartes: '[M]any people do not know themselves what they believe, since believing something and knowing that one believes it are different acts of thinking, and the one often occurs without the other' [Discourse on Method, cited in Wilson (2012), p. 669, fn. 3; AT VI 23]; 'For experience shows that those who are the most strongly agitated by their passions are not those who know them best' [Passions, cited in Wilson (2012), p. 669, fn. 3; AT XI 349-350]. However, it is not clear from this material that Descartes did accept the possibility of mental state scepticism. The quotations provided only suggest that Descartes noted the difference between having the belief that p, and having the second order belief that one believes that p, and that these states are independent. Furthermore, Descartes clearly did not accept mental state scepticism. After the cogito Descartes vows to meditate and 'subtract anything capable of being weakened [...] so that what is left at the end may be exactly and only what is certain and unshakeable' [AT VII 25; (1984), p. 17]. After this subtraction, we get an 'I' who 'understands some things, who affirms that this one thing is true, denies everything else, desires to know more, is unwilling to be deceived, imagines many things even involunAnother Failed Refutation of Scepticism 27 teorema Vol. XXXVI/2, 2017, pp. 19-30 tarily, and is aware of many things which apparently come from the senses? Are not all these things just as true as the fact that I exist, even if I am asleep all the time, and even if he who created me is doing all he can to deceive me?' [AT VII 28-29; (1984), p. 19]. It is hard to reconcile this with mental state scepticism, but this is precisely what Wilson's mental state sceptic needs: I must be sceptical about my attitude of being sceptical whether the external world exists. We need to be persuaded that someone who accepts Cartesian scepticism about the external world should also accept Cartesian scepticism about mental states. What exactly does the mental state sceptic say to us at step 2? The first level sceptic has just argued (let H be the sceptical hypothesis and P the external world proposition): ~K(~H), (~K(~H)→ ~K(P)), therefore ~K(P).8 Where could the mental state sceptic's deceiver get traction on this? Which one of the premises might be a deception brought on by an evil demon? Suppose the first: if this is a deception then K(~H), and I could only know that I am not being undetectably deceived about the external world if such deception was impossible or ruled out by something else I know, such as the existence of a benign God. The problem now is that the mental state sceptic has to create a scenario in which I am undetectably deceived that undetectable deception is possible.9 So the mental state sceptic must address the second premise and show that it is possible that, appearances to the contrary, ~(~K(~H)→~K(P)) and thus it is possible I am deceived about the second premise. That deception requires a scenario in which the possibility of undetectable deception about P does not undermine knowledge that P, which is, of course, hardly a sceptical scenario. V. CONCLUSIONS In this paper, we have presented Wilson's regress argument against Cartesian scepticism and offered three avenues of response. We first suggested that the Cartesian sceptic can get to her desired conclusion without having to go via the assertion that she is sceptical whether the external world exists. This generates an alternative regress which is not unstable and may not even get started. Next, we argued that if the Cartesian sceptic does want to assert that she is sceptical whether the external world exists, she can go ahead and do so. Wilson argues that the regress generated by the assertion that one is sceptical whether the external world exists must be stopped. We countered that that assertion is not one the Cartesian need 28 Tom Stoneham and Ema Sullivan-Bissett teorema Vol. XXXVI/2, 2017, pp. 19-30 make, and if she does make it, whatever regress it leads to is not in need of stopping. Finally, we argued that Wilson is too quick at step 2 and that hypotheses of deception do not generate the mental state scepticism she needs at that point. So, yet another attempt to show that we should reject Cartesian scepticism because it is somehow self-defeating fails. Department of Philosophy Sally Baldwin A University of York Heslington, YO10 5DD, UK E-mail: tom.stoneham@york.ac.uk Department of Philosophy European Research Institute University of Birmingham Edgbaston, B15 2TT UK E-mail: e.l.sullivan-bissett@bham.ac.uk ACKNOWLEDGMENTS Tom Stoneham acknowledges the support of the Chinese Ministry of Education's Foreign Cultural and Educational Scholars Project. Ema Sullivan-Bissett acknowledges the support of the European Research Council (Grant agreement: 616358). Both authors are grateful to the Mind and Reason research group at the University of York, and an anonymous referee for this journal, for comments and discussion on an earlier version of this paper. NOTES 1 We define a Cartesian sceptic as one who appeals to the possibility of massive deception, either by an evil demon, an evil scientist, or some other scenario. We assume that this sceptic offers such a possibility as the premise of an argument which concludes with a sceptical claim. Paul Noordhof has pointed out an alternative: the sceptic may want contemplation of the sceptical scenario to cause uncertainty, doubt, and confusion, thereby undermining the epistemic status of what the subject believes. Setting aside the correctness of the assumption that knowledge requires an absence of uncertainty, it seems that this sceptic is more of an epistemological bully than a philosophical opponent, so we will not address him in what follows. 2 This is one point where the Cartesian and Pyrrhonian sceptic differ. Another is over the propositional attitudes a sceptic ought to have. As Sextus Empiricus puts the Pyrrhonist view: Another Failed Refutation of Scepticism 29 teorema Vol. XXXVI/2, 2017, pp. 19-30 When we say, Sceptics do not hold beliefs, we do not take 'belief' in the sense in which some say, quite generally, that belief is acquiescing in something; for Sceptics assent to the feelings forced on them by appearances. [Outlines I.13; (2000), p. 6]. 3 Throughout we follow Wilson in using the language of knowing whether (rather than knowing that). We assume that to know whether p is to either know p or know ~p, such that if p is true, knowing that p and knowing whether p are equivalent. Someone in a state of ignorance about p will therefore express themselves as wanting to know whether p. But an observer who knows p is true might express this as their wanting to know that p, because the only way for them to know whether p would be by knowing that p. 4 It might be pointed out that Descartes' solution to the sceptical problem involves, in Meditation II, a commitment to knowing of himself that he is doubting, which seems to support Wilson's reading of the conclusion of the Cartesian arguments. Given that Descartes' use of sceptical arguments is methodological, we should distinguish the conclusion of the argument – which he does not accept – from the mental state he is in after running through the arguments. He has an apparently sound argument to the conclusion that he cannot know anything about the external world. He does not want to accept the conclusion, so the appropriate state of mind is temporary, methodological doubt ('dubitare' was the Stephanus translation of Sextus' 'aporia'). Doubt is thus not the conclusion of the sceptical arguments Descartes provides but their effect upon him, an effect he introspects in Meditation II. 5 Yuval Avnur makes a similar point by distinguishing a Practicing Sceptic, who doubts, from a Theoretical Sceptic, who 'holds that we should be Practicing sceptics' [Avnur (2016, p. 81]. Our Theoretical sceptic merely asserts that she cannot know and leaves the normative claims to the prescriptively inclined. 6 A Pyrrhonian sceptic would be one who achieved tranquillity, not insanity, when faced with this problem. So at best Wilson has converted the Cartesian sceptic to Pyrrhonism. 7 Thanks to Christopher Jay for this point. 8 We follow Duncan Pritchard in opting for the modus ponens formulation of the sceptic's argument here [(2002), p. 217]. 9 Relativizing the deceptions to subject matters, viz. my mental states and the external world, makes clear that step 2 requires additional arguments over and above what was needed for step 1. 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