POLISH JOURNAL OF PHILOSOPHY Vol. VI, No. 1 (Spring 2012), 89-99.
Critical Notices
Sextan Skepticism and Self-Refutation*
Renata Ziemińska University of Szczecin
Luca Castagnoli, Ancient Self-Refutation. The Logic and History of the Self- Refutation Argument from Democritus to Augustine, Cambridge: Cambridge University Press 2010, pp. XX+394. Hardback, ISBN 9780521896313.
Abstract. In his book Ancient Self-Refutation L. Castagnoli rightly observes that self- refutation is not falsification; it overturns the act of assertion but does not prove that the content of the act is false. He argues against the widely spread belief that Sextus Empiricus accepted the self-refutation of his own expressions. Castagnoli also claims that Sextus was effective in answering to the self-refutation charge. The achievement of the book is the discovery that in passages where Sextus seems to embrace the self- refutation of his expressions (PH 1.14-15), he does not use the term peritropé, technical for self-refutation, but the term perigraphé, which means self-bracketing. Self- bracketing is weakening one’s own thesis, but not overturning it. Castagnoli claims that Sextus embraces the self-bracketing of his expressions, but never accepts their self- refutation. However, Castagnoli is not right in saying that self-refutation is a shameful mistake for everybody. The mature skeptic cannot even think that self-refutation is wrong, because it would be a dogmatic view. Sextus seems to accept self-refutation at the end of Against the Logicians, where he presents the argument against proof and the metaphor of the ladder (M 8.480-1). Regardless of Sextus’ declarations, we have reason to think that he does not avoid self-refutation in a pragmatic sense. Self-bracketing of his position is not a consistent dialectical strategy, as Castagnoli writes, but the end of a rational discussion. Sextus avoids absolute self-refutation (we cannot falsify what he suggests), but he is unable to avoid pragmatic self-refutation (there is no way to assert his position without contradiction). This is the case even if Sextus refuses to assert his position.
* Translated into English by Agnieszka Ziemińska. Scientific work financed by funds for science in years 2009-2012 as a research project N N101 109137. 90 Critical Notices—Book Reviews—Notes on Books
The book written by Luca Castagnoli is about self-refutation in ancient philosophy. I focus on Sextus Empiricus, whose extant skeptical works are the main source of ancient self-refutation arguments (apart from Plato’s Theaetetus and Aristotle’s Metaphysics). Sextus Empiricus introduces peritropé (περιτροπή) as the technical term for self-refutation, presents some self-refutation arguments concerning other philosophers, reports some self-refutation arguments against skeptical statements, and appears to accept the self-refutation of his own statements. Contrary to previous scholars (Burnyeat, 1976a; 1976b; McPherran, 1987), Castagnoli claims that Sextus does not accept the self-refutation of his own statements, especially since self-refutation is a shameful mistake, just being caught in self-contradiction (p. 252). Additionally, according to Castagnoli, Sextus’ defense of the consistency of the Pyrrhonian outlook, i.e. his dialectical strategy of answering the self-refutation charge by non-assertion, is refined, coherent, mature and systematic (p. 308). Castagnoli adopts an initial, broad definition of the self-refutation argument as “any argument which aims at showing that (and how) something is ‘self-refuting’, i.e. refutes itself” (p. 3). Since Pyrrho, skeptics have been accused of self-refutation. Carneades is aware of the impending charge of self-refutation when he says (in Cicero’s account Ac. 2.IX.28) that he cannot accept the thesis “nothing is apprehensible,” despite its being the essence of his view. If he had accepted the thesis, he would either have contradicted himself or made an unauthorized exception. According to Aristocles (in Preparation for the Gospel by Eusebius of Cesarea), skeptics like Aenesidemus “require to give assent to no one, but they command to believe them; furthermore, although they say they know nothing, they refute everyone, as if they knew well” (Eus. PE 14.18.7). Most self- refutation arguments against skeptical theses are presented by Sextus himself, who after centuries of skeptical polemics tries to deal with this charge. A textbook example of using the self-refutation argument is rejecting Protagoras’ thesis that everything is true, and Xeniades’ thesis that everything is false. Sextus writes:
One cannot say that every appearance is true because of the ‘turning about’ (περιτροπής), as Democritus and Plato taught, speaking against Protagoras. For if every appearance is true, then even not every appearance’s being true, since it takes the form of an appearance, will be true, and thus every appearance’s being true will become false. (M 7.389-3902)
1 I quote as M8 and M7 the two books of: Sextus Empiricus, Against the Logicians transl. Richard Bett, Cambridge and New York: Cambridge University Press 2005; and Critical Notices—Book Reviews—Notes on Books 91
If Protagoras was right, claiming that every opinion is true, it would mean that his opponents’ opinion is also true (see Plato Theaetetus, 171A). Making that statement actually refutes it. The same is the case with Xeniades’ thesis. “For if all appearances are false and nothing is true, ‘Nothing is true’ is true… And so Xeniades…has been brought round to the opposite of his thesis” (M 7.399, see M 8.55). According to M. Burnyeat, a self-refuting thesis is a “thesis falsified by its own content” (Burnyeat 1976, p. 59). Castagnoli does not agree with this reading of the concept of self-refutation. In his opinion there is no falsification3 here because self-refutation does not give an objective proof of the falsity of the thesis; it does not rule out that what is stated in it is the case (p.100). Self-refutation does not concern the thesis in abstracto (p. 285), but the act of speech by a person who decides to make a statement like “Everything is false.” Such a person is forced to accept the opposite thesis. If she states that nothing is true, then in the act of uttering this statement she assumes that her saying is true, and has to admit that at least one truth exists, which is contradictory to her initial thesis (p.119). Self- refutation overturns the act of assertion but does not prove that the stated thesis (the content of the act of assertion) is false. Of course, on a pragmatic level this discredits the thesis itself and is a reason to dismiss it. Until now, at least two types of self-refutation have been distinguished: absolute (the statement is falsified because of its content, for instance, “Nothing is true”) and pragmatic (the statement is falsified because of the way it is presented, for example, “I present a proof that there is no proof”). Castagnoli shows that in the strict sense it is not the theses (contents) that are self-refuting, but the acts of stating those theses. Therefore there is no absolute self-refutation, but only pragmatic. Saying Nothing is true is self- refuting not because of its content, but because of its assertion as true. If the sentence was said as a joke or an expression of feelings, there would be nothing self-refuting about it. It seems a thesis is absolutely self-refuting only when it is self-contradictory (Castagnoli does not want to call such cases self-refutation). Self-refutation is a situation in a discussion when the act of stating thesis p is contradictory to the content of the statement, and the person stating p is
as PH: Sextus Empiricus, Outlines of Scepticism transl. by Julia Annas, Jonathan Barnes, Cambridge and New York: Cambridge University Press 2000. 3 “in neither case do ancient self-refutation arguments prove, or aim to prove, the falsehood of the thesis which incurs defeat: the thesis cannot survive dialectical scrutiny, and in some cases does not ever bear articulating, but typically the self- refutation argument does not exclude the possibility that what is expressed is the case” (s.355-356). 92 Critical Notices—Book Reviews—Notes on Books forced to accept not-p. In every case of self-refutation “the person who states that p ends up admitting that not-p in the act of, or as a consequence of, stating that p” (p. 173). Self-refutation is a type of dialectic argument against some acts of making a statement. However, what Castagnoli does not mention is that, it is possible, in a secondary sense, to talk about self- refuting theses if in typical situations the act of stating them leads to self- refutation. Castagnoli rightly notes that the anti-skeptical arguments reported by Sextus have the structure of dilemmas. One side of the dilemma leads to self-refutation, but the other opens the possibility of escaping it. Such is the structure of the stoic counterarguments against the skeptical thesis that no cause, sign, proof, or criterion of truth exists. “The dogmatists typically reply by asking how on earth the skeptic declares that nothing is a criterion. For he says this either without a criterion or with a criterion. And if it is without a criterion, he will become untrustworthy; but if it is with a criterion, he will be turned about (περιτραπήσεται), and in saying that nothing is a criterion he will agree to employ a criterion for the purpose of showing this” (M 7.440). Self-refutation is expressed in the words: “he will be turned about,” which are a translation of one of the forms of peritropé. In accordance with the previous reconstruction of the concept of self- refutation, the quoted argument does not lead to the falsification of the thesis that no criterion exists. The thesis No criterion exists is not self- contradictory. This thesis is self-refuting only when it is stated as rational (based on reasons) and true. Sextus later claims that skeptics are not in the habit of defending theses they believe in (M 7.443). Therefore he chooses the first horn of the dilemma, where self-refutation is avoided by choosing the option of being “untrustworthy.” Sextus concedes that this option “does not deserve faith,” but he does not seem afraid of the consequences of such a choice. Castagnoli argues against the widely spread belief that Sextus accepted self-refutation.4 For instance, McPherran (1987, p. 290-1) writes that Sextus Empiricus was ready to “accept—and even embrace—the charge of self- refutation.” According to Castagnoli, self-refutation is an embarrassing, dialectic sin everyone should avoid (one not only looses the battle but is also ridiculed). Nobody would like to be caught making this mistake (p. 251, 354). Castagnoli claims that
Sextus never accepts, and so much the less embraces, the dogmatic charge of self-refutation; what is interpreted by McPherran and many others as an
4 “I will take this acceptance of self-refutation (peritrope) as a defining character of Pyrrhonian skepticism as I understand it” (Fogelin, 1994, p. 4). “At all events they [sc. the Pyrrhonists] happily embraced self-refutation” (Hankinson, 1995, p. 18). Critical Notices—Book Reviews—Notes on Books 93
admission of self-refutation is best reconstructed as a refined dialectical tool that Sextus used against the dogmatic charges of inconsistency and self- refutation. I shall also suggest that this tool could be used by an ancient Pyrrhonist without any need for dubious external supports, ad hoc justifications or philosophical bluffs. (p. 252)
So, according to Castagnoli Sextus does not accept the self-refutation of his own position and Sextus is effective in avoiding the charge. The ground for the standard reading is those passages in which Sextus clearly writes that the Skeptic’s5 words are self-cancelling and that this is not a problem, but the consequence of the skeptical position. “Just as the phrase ‘Everything is false’ says that it too, along with everything else, is false (and similarly for ‘Nothing is true’), so also ‘In no way more’ says that it too, along with everything else…cancels itself along with everything else. And we say the same for the other Sceptical phrases…Sceptics utter their own phrases in such a way that they are implicitly cancelled by themselves” (PH 1.14-15). Sextus writes that the Skeptic’s statements resemble sentences like “Everything is false” or “Nothing is true,” which are the clearest examples of self-refutation. He also compares the Skeptic’s words to purgatives. They “can be destroyed by themselves, being cancelled along with what they are applied to, just as purgative drugs do not merely drain the humours from the body but drive themselves out too along with the humours” (PH 1. 206). What is Castagnoli answer to those passages? Castagnoli is not bothered by the quoted passages from Outlines of Scepticism because the important finding of his book is that in those passages Sextus does not use the word peritropé or verb peritrépein, technical for self-refutation, but a different word, perigraphé (or verbs perigráphein, simperigráphein), which means “self-cancellation” or better yet “self-bracketing” (p. 252-253). Peritropé and perigraphé refer to two kinds of self-elimination; peritrepein and perigraphein are two kinds of enairein (p. 275). According to Castagnoli, the Skeptic indeed embraces the self-elimination or self-cancellation of his statements, but not their self- refutation. On this reading, skeptical statements supposed to express appearances and not stated as true are immune to self-refutation (only asserting some thesis as true later enables its self-refutation). The Skeptic’s theses could be charged with self-refutation when interpreted dogmatically. But when they
5 The term “Skeptic” with capital “S” refers to the representative of the kind of skepticism described in Sextus’ texts. Similarly, the term “Dogmatist” with capital “D” refers to Sextus’ opponent. In ancient philosophy Dogmatism does not have such a pejorative connotation as today. A Dogmatic is a person who accepts any judgment as true, that is has any belief (cf. Pellegrin, 2010, p. 125). 94 Critical Notices—Book Reviews—Notes on Books are interpreted as an expression of phenomena, as Sextus wishes, they do not state anything and thus cannot be self-refuted (p. 267). So, according to Castagnoli Sextus’ non-assertion discourse is effective in avoiding the self- refutation charge. Castagnoli suggests that the metaphor of “self-bracketing” is the key to grasping the status of skeptical statements. As he writes, the word perigraphé was used to mark a cancellation by the copyist or reviser, usually by bracketing. Bracketing supposedly shows that those statements should not be interpreted dogmatically, but their content should stay. It is not a final removal of the content, but a guideline that it should not be treated as real (p. 269). Bracketing is not reversing the thesis, like in self- refutation, but only weakening it. Besides, Castagnoli stresses, bracketing is a defense strategy that Sextus is using against the charge of self-refutation; it is not self-refutation itself. The picture of Sextan skepticism is definitely fuller after Castagnoli’s book. It is clear now that Sextus Empiricus does not say about his own statements that they are self-refuting. It is natural that he uses some milder term, a euphemism, to describe his own dialectical situation. However, using two different words does not entail any practical difference in meaning (after all, both terms mean self-elimination) and does not entail that Castagnoli’s interpretation is in fact effective in absolving Sextus from the self-refutation charge. Castagnoli is not right in saying that self-refutation is a shameful mistake for everybody (p. 251). It is so only for people accepting some logical rules within the dogmatic game. The mature Skeptic cannot even think that self-refutation is wrong: to do so would be to accept the dogmatic viewpoint. Thus, she can be indifferent about it (and can even use it in therapy). Such an attitude seems to be taken by Sextus at the end of Against the Logicians, where he presents the arguments against proofs and the metaphor of the ladder (M 8.463-481). Burnyeat and McPherran claim that there is a pragmatic self-refutation there and that the initial thesis (no proof exists) is falsified by the way it is presented in the form of a proof. It is possible to agree with Castagnoli that there is no falsification here, but it is hard to agree that Sextus in this passage considers self-refutation to be a mistake and successfully avoids the self-refutation charge.
For the dogmatic philosophers think that the argument maintaining that there is no demonstration is turned about by itself (περιτρέπεσθαι), and determines demonstration by the very means by which it does away with it. Hence, setting themselves against the skeptics, they say: ‘the person who says that demonstration is nothing says that demonstration is nothing either with the use of a bare and undemonstrated assertion, or by demonstrating this with an argument. And if it is with the use of a bare assertion, none of those receiving Critical Notices—Book Reviews—Notes on Books 95
the demonstration will believe him, since he is using a bare assertion, but he will be stopped by the opposite assertion, when someone says that there is demonstration. But if it is by demonstrating that there is no demonstration (their words), he has right away agreed that there is demonstration; for the argument that shows that there is no demonstration is a demonstration of there being demonstration’. (M 8.463-464)
Sextus answers this destructive retort in four phases. The first phase is an attempt to throw the burden of proof at the Dogmatist, the second is a refusal to accept the conclusion of the argument, and the third is an attempt to treat the argument against proof as an exception. McPherran (1987, p. 301) considers all three of those phases to be weak, while Castagnoli sees the second one as already successful (he assumes that it is enough to refuse to accept one’s own conclusion to avoid self-refutation). The final and most important phase of Sextus’ defense consists in the reference to the metaphors of purgatives and the ladder. McPherran thinks that in the final phase Sextus simply accepts self-refutation while Castagnoli sees it as a final defense against it:
Just as purgatives after driving the fluids out of bodies eliminate themselves as well, so too the argument against demonstration, after doing away with all demonstration, can cancel itself as well. And again, just as it is not impossible for the person who has climbed to a high place by a ladder to knock over the ladder with his foot after his climb, so it is not unlikely that the skeptic too, having got to the accomplishment of his task by a sort of step-ladder—the argument showing that there is not demonstration—should do away with this argument. (M 8.480-481)
The metaphor of the ladder presents self-refutation as a natural and acceptable process and not as a mistake which is shameful and should be avoided. Castagnoli does not notice this and tries to use his distinction between self-refutation and self-bracketing in understanding AAP. According to Castagnoli AAP is not self-refuting because it is not a proof (a skeptic only reports her own impressions, see p. 286), and Sextus brackets this argument like all the other skeptical statements. If AAP is not a proof then its conclusion cannot refer to it. “The self-bracketing of AAP that Sextus accepts and embraces has as its result the expunction of AAP from the set of the alleged proofs” (p. 291). According to Castagnoli, only interpreted as a proof (dogmatically) does AAP refer to itself and is self- refuting. A Skeptic who does not treat any of her arguments as valid, and brackets them all, is not in danger of self-refutation. The self-bracketing of all her statements protects her from self-refutation. Castagnoli fails to present skepticism in a dialectical context. He relieves the Skeptic of all dialectical duties. When someone states something during a discussion, she accepts her thesis as true and is obliged to defend and justify it. For instance, in Sextus’ reading, Protagoras’ thesis 96 Critical Notices—Book Reviews—Notes on Books that everything is true, stated as true or defended against the opponent, is self-refuting. Castagnoli writes that Protagoras’ thesis turns out to be weak when it is submitted to dialectical scrutiny (because Protagoras, after presenting his thesis, cannot say that his opponent is wrong; p. 66). Meanwhile, when it comes to the Skeptic’s theses, Castagnoli, following Sextus, accepts their self-bracketing, which consists in the lack of accepting them as true and in the refusal to defend them. It is a dialectic evasion which cannot be accepted as a consistent dialectical strategy (as Castagnoli accepts it (p. 252)), but as the end of rational discussion. The Skeptic could be asked what the goal of her discourse is. If she states something as true then her conclusion against proofs is self-refuting and she contradicts herself; if she is only practicing a persuasive therapy, she is outside rational discourse; if she argues dialectically on the basis of the doctrines and rules endorsed by other philosophers, she can show the problems of the philosophers, but cannot propose any alternative self- contained position. In first case her position is self-refuting, in the second case her position is uninteresting, in the third case she has no position at all and that is why it cannot be the subject of discussion. The Skeptic’s dialectical evasion becomes clear in the light of the distinction between mature and developing skepticism. This distinction was introduced by Bailey (1990) and Thorsrud (2009). McPherran (1987) presented skepticism not as a thesis but as a process developing over time. Bailey noticed that a mature skeptic has radically different views than a developing one. The first one rejects all beliefs, arguments and rules, which can be illustrated as throwing away the ladder. A developing skeptic must have many beliefs, follow the law of non-contradiction and accept the conclusions of some correct arguments in order to climb to the top of the ladder. Castagnoli does not use this distinction (only in note 82 (p. 278) does he mention the mature and the developing skeptic) and assumes, like Hankinson, that the right form of skepticism is the mature skepticism, after throwing away the skeptical ladder. However, it seems that this interpretation is inadequate in regard to the content of Sextus’ texts. If skepticism is restricted to just the mature form, then skepticism becomes a form of irrationalism (suspending logical rules), and thus it becomes impossible to explain why the works of Sextus Empiricus are a collection of sophisticated, rational arguments. If we are to judge skepticism in a rational discussion, then only the skeptic from before throwing away the ladder, that is the developing skeptic, is able to take part in the discussion and only such skepticism can be judged in a rational way. The metaphor of the ladder, which is climbed and later thrown away, suggests that skepticism is a process of thinking that develops over time and has at least two phases: climbing the ladder and throwing it away. The Critical Notices—Book Reviews—Notes on Books 97 arguments gathered in Sextus’ work are the steps of the ladder and the self- refutation of one’s own arguments is throwing the ladder away. After throwing away the ladder all those arguments do not hold much value, but they do remain a therapeutic means and a guide for those adepts of skepticism who are at the bottom of the ladder. The mature skeptic does not really accept any arguments or logical rules. She also does not claim anything. She is no longer a participant in the discussion, one who seeks truth with the help of rational arguments.6 Throwing away the ladder represents an escape from discussion, an inability to justify one’s standpoint, and the entering into the phase of esoteric wisdom. When analyzing self-refutation, it is useful to take into consideration the situation of the developing skeptic, not only the mature one. The developing skeptic cannot refuse to accept the conclusions of her arguments. And when she accepts the argument against proof, she is in danger of self-refutation. Not without reason is the argument against proofs found at the very end of Against the Logicians. It seems to be the clearest example of skeptical argumentation which ends in self-refutation and the skeptic is left with no choice but to throw away the ladder, that is, to suspend judgments about the rules of rational discourse. I agree with McPherran that the mature skeptic after throwing away the ladder embraces the self-refutation of her own words. She has no reason to treat self-refutation as a mistake any more. This weakens the Castagnoli thesis that between peritropé and perigraphé there is a basic difference. The difference seems to consist in nothing more than the presuppositions of Skeptical and Dogmatic discourse. It seems there is no difference in content, like when the same word is spoken by a Skeptic and by a Dogmatic. For someone taking the non-assertion discourse as skeptical fantasy, the difference is close to nothing. By using a different term, Sextus wanted to distinguish the mature skeptic from a regular Dogmatic who falls into self-refutation because of carelessness and for whom self-refutation is an embarrassment. Instead of reversing the thesis, he talks about bracketing it (because it was never accepted). Instead of peritropé there is perigrafé.7 In both cases it is rejecting one’s own words. The Skeptic, unlike a regular debater, does it without waiting for a retort; she outruns her interlocutors and eliminates her own statements. But there is no reason why the mature skeptic should be ashamed of self-refutation and could not embrace the self-refutation of her own position.
6 It is hard to agree that the mature skeptic is still seeking the truth (see Perin, 2010, p. 31). 7 Hankinson noticed it, but he took it as a minor verbal difference: “Hence he [sc. The Sceptic] can be perfectly happy about the self-refuting (or as Sextus prefers to say, self-cancelling) nature of his expressions, or phonai” (Hankinson, 1995, p. 299). 98 Critical Notices—Book Reviews—Notes on Books
Castagnoli’s thesis is a curious alternative to the traditional interpretation, but the verbal difference between peritropé and perigrafé does not mean that Sextus at the end of Against the Logicians treated self- refutation as a shameful mistake and that he really managed to avoid self- refutation, even if he tried. It seems that Sextus, who earlier tried to avoid self-refutation by being particularly careful in presenting his arguments, at the end of Against the Logicians touches the limits of rational argumentation and embraces self-refutation. For the mature skeptic it does not really matter whether she accepts or avoids self-refutation (after refusing to accept any rules of rational thinking). The mature skeptic is outside the dialectical context and any reasonable discussion of her position is pointless (because she has no independent position at all). If we want to rationally asses the skeptical position, we should keep the standpoint of the developing skeptic. She, at the top of skeptical ladder, definitely does not have any opportunity to avoid self-refutation (she has rational and dialectical obligations), so she can only accept it and then throw away the ladder. It is a pity that Castagnoli neglected the position of the developing skeptic as not a fully skeptical one. In fact the developing stage of skepticism is the only version where skeptical arguments are treated seriously. Yet they are the treasury of the skeptical position and the most important thing we are interested in. Castagnoli rightly observed that ancient self-refutation was pragmatic, described in a dialectical context, the context of discussion between philosophical positions. I miss this context in his analysis of Sextus’ position. When we put Sextan conclusions, like “There is no valid proofs” into dialectical context, asserting them is immediately self-refuting.At the end of his book Castagnoli admits that the Skeptic “is unable to defend his own position without the further implication that he is thereby committed to his adversary’s” and is unable “to engage in serious dialectic and stand by his thesis facing opposition” (p. 316). Sextus avoids the absolute self-refutation of his position (we cannot falsify what he suggests) but, against Castagnoli’s reading, he is unable to avoid the pragmatic self-refutation (there is no way to assert his position without contradiction). This refers to Sextus’ suggested general position (no thesis is ever rationally preferable to its contradictory) and to the particular theses his position consists of (there is no justified belief, no rational criterion of truth, no valid proof). When we assert them in a rational discussion, trying to give some reason for them, they end up being self- refuting. Also, Sextus’ claim that he has no beliefs cannot be asserted without self-refutation: if Sextus asserts that he believes nothing (PH 1.13), he presupposes that he believes that he believes nothing, thus denying the spoken statement. The content of his statement is in conflict with the act of assertion. Sextus can repeat that he asserts nothing, but this is not an Critical Notices—Book Reviews—Notes on Books 99 argument but the end of discussion. That is why not only self-refutation, but also non-assertion is a dialectical disaster. Sextus’ strategy of non-assertion does not seem to be effective in answering the charge of self-refutation of his philosophical position.
References
Bailey, A. (1995). Pyrrhonean Scepticism and the Self-Refutation Argument. The Philosophical Quarterly, 40, 27-44. Burnyeat, M. F. (1976a). Protagoras and Self-Refutation in Plato’s Theaetetus. The Philosophical Review, 85, 172-195. Burnyeat, M. F. (1976b). Protagoras and Self-Refutation in Later Greek Philosophy. The Philosophical Review, 85, 44-69. Fogelin, R. (1994). Pyrrhonian Reflections on Knowledge and Justification. Oxford: Oxford University Press Hankinson, R. J. (1995). The Sceptics. London and New York: Routledge,. McPherran, M. (1987). Skeptical Homeopathy and Self-refutation. Phronesis, 32, 290-328. Pellegrin, P. (2010). Sextus Empiricus. In R. Bett (Ed.), The Cambridge Companion to Ancient Scepticism. Camgridge: Cambridge University Press. Perin, C. (2010). The Demands of Reason. An Essay on Pyrrhonian Scepticism. Oxford University Press. Sextus Empiricus (2005). Against the Logicians (R. Bett Trans.). Cambridge and New York: Cambridge University Press. Sextus Empiricus (2000). Outlines of Scepticism (J. Annas, J. Barnes Trans.). Cambridge and New York: Cambridge University Press. Thorsrud, A. (2009). Ancient Scepticism. Berkeley and Los Angeles: University of California Press.