Doctor of Philosophy / This dissertation argues that if we are to respect the common sense perspective then Pyrrhonian scepticism can be neither avoided nor defeated. While Pyrrhonian scepticism can be diagnosed it cannot be cured, at least, so long as we take a non-revisionary attitude towards common sense. The fundamental reason for this is that Pyrrhonian scepticism derives from the application of norms of inquiry that constitute part of the content of common sense in unusual but not fanciful or impossible situations. Implicit in this dissertation is a distinction between Cartesian and Pyrrhonian scepticisms, and for present purposes these two scepticisms can be distinguished on two criteria. First, unlike Cartesian scepticism, Pyrrhonian scepticism is not global in its doubts. It is not global because it does not attempt to question our entitlement to entire domains of commitment, for instance commitments to anything beyond the content of our perceptions, all at once. Nor does Pyrrhonism attempt to deny the possibility of knowledge. Rather, Pyrrhonian scepticism questions our entitlement to one commitment at a time and is hence iterative rather than global. This leads to the second far more interesting criterion in that unlike its Cartesian cousin Pyrrhonian scepticism claims not to be revisionary of the common sense perspective. In fact Pyrrhonian scepticism represents itself as the common sense perspective under special conditions. On this reading Pyrrhonian scepticism is a form of common sense scepticism. The claim that Pyrrhonian scepticism is commonsensical calls for a clarification of in what exactly the common sense perspective consists, and its relationship to scepticism. Of particular interest in this regard is a position that has been called Common Sense Naturalism (CSN). CSN consists, in part, in three important claims. First, that we are constrained, both logically and psychologically, to take ourselves to have an entitlement to common sense. Second, that because we are thus constrained, we have an entitlement to those commitments that constitute the content of common sense. Third, that the content of common sense is inherently anti-sceptical. These three claims jointly warrant Page 5 Page 6 the conclusion that appeals to commitments to which we are commonsensically entitled can feature prominently in refutations of scepticism. I argue that CSN is incorrect in that even if we have an entitlement to our common sense commitments we have an equally valid entitlement to Pyrrhonian scepticism, as Pyrrhonian scepticism can be derived from the common sense perspective itself. I also argue that CSN is correct but misleading in suggesting that we are constrained, both logically and psychologically, to take ourselves to have an entitlement to the content of common sense. CSN is correct in that we are always forced to take ourselves to be entitled to some commonsensical commitments but overlooks the fact that the content of these commitments varies, becoming at times amenable to Pyrrhonian scepticism. In fact what we take to be commonsensical is sensitive to our mood at the time. This can be used to explain that feature of the phenomenology of scepticism according to which Pyrrhonian scepticism is a recurrent but not a constant problem. Presenting these arguments requires both that the nature of CSN be clarified (chapter 1), that the relationship between common sense and Pyrrhonian scepticism be established (Chapter 2). Finally, we must also provide an account of the content of common sense be given (Chapter 3) which provides warrant for continued inquisitive activities even after the emergence of Pyrrhonian scepticism from within common sense.

Doctor of Philosophy / This dissertation argues that if we are to respect the common sense perspective then Pyrrhonian scepticism can be neither avoided nor defeated. While Pyrrhonian scepticism can be diagnosed it cannot be cured, at least, so long as we take a non-revisionary attitude towards common sense. The fundamental reason for this is that Pyrrhonian scepticism derives from the application of norms of inquiry that constitute part of the content of common sense in unusual but not fanciful or impossible situations. Implicit in this dissertation is a distinction between Cartesian and Pyrrhonian scepticisms, and for present purposes these two scepticisms can be distinguished on two criteria. First, unlike Cartesian scepticism, Pyrrhonian scepticism is not global in its doubts. It is not global because it does not attempt to question our entitlement to entire domains of commitment, for instance commitments to anything beyond the content of our perceptions, all at once. Nor does Pyrrhonism attempt to deny the possibility of knowledge. Rather, Pyrrhonian scepticism questions our entitlement to one commitment at a time and is hence iterative rather than global. This leads to the second far more interesting criterion in that unlike its Cartesian cousin Pyrrhonian scepticism claims not to be revisionary of the common sense perspective. In fact Pyrrhonian scepticism represents itself as the common sense perspective under special conditions. On this reading Pyrrhonian scepticism is a form of common sense scepticism. The claim that Pyrrhonian scepticism is commonsensical calls for a clarification of in what exactly the common sense perspective consists, and its relationship to scepticism. Of particular interest in this regard is a position that has been called Common Sense Naturalism (CSN). CSN consists, in part, in three important claims. First, that we are constrained, both logically and psychologically, to take ourselves to have an entitlement to common sense. Second, that because we are thus constrained, we have an entitlement to those commitments that constitute the content of common sense. Third, that the content of common sense is inherently anti-sceptical. These three claims jointly warrant Page 5 Page 6 the conclusion that appeals to commitments to which we are commonsensically entitled can feature prominently in refutations of scepticism. I argue that CSN is incorrect in that even if we have an entitlement to our common sense commitments we have an equally valid entitlement to Pyrrhonian scepticism, as Pyrrhonian scepticism can be derived from the common sense perspective itself. I also argue that CSN is correct but misleading in suggesting that we are constrained, both logically and psychologically, to take ourselves to have an entitlement to the content of common sense. CSN is correct in that we are always forced to take ourselves to be entitled to some commonsensical commitments but overlooks the fact that the content of these commitments varies, becoming at times amenable to Pyrrhonian scepticism. In fact what we take to be commonsensical is sensitive to our mood at the time. This can be used to explain that feature of the phenomenology of scepticism according to which Pyrrhonian scepticism is a recurrent but not a constant problem. Presenting these arguments requires both that the nature of CSN be clarified (chapter 1), that the relationship between common sense and Pyrrhonian scepticism be established (Chapter 2). Finally, we must also provide an account of the content of common sense be given (Chapter 3) which provides warrant for continued inquisitive activities even after the emergence of Pyrrhonian scepticism from within common sense.

Há um consenso nos meios crítico e acadêmico de que Joaquim Maria Machado de Assis é o maior ficcionista brasileiro. Além da qualidade inegável, sua ficção é notável por sua dimensão, atingindo uma dezena de romances e mais de duzentos contos. Com esta união singular entre extensão e qualidade, a obra machadiana acumulou a maior fortuna crítica no Brasil e uma das maiores da literatura universal. Ainda assim, sua fortuna é a que mais cresce no Brasil. Diante de tamanha dedicação dos estudiosos, em que seria relevante a apresentação de mais uma dissertação sobre o Bruxo do Cosme Velho? Acreditando que, apesar do tamanho da investigação que já se fez sobre Machado, alguns dos aspectos cruciais da vida e da obra do escritor ainda não foram devidamente elucidados, este trabalho nasce com a intenção de contribuir para a diminuição dessa lacuna. Um desses aspectos é o conteúdo filosófico da ficção machadiana. Durante muitas décadas, a ideia de que Machado de Assis se alinhara filosoficamente ao pessimismo foi hegemônica. Entretanto, muitas características da ficção machadiana, tais como o humour e a ironia, podem ser sinais de outra orientação filosófica: o ceticismo. A identificação entre Machado e ceticismo não é, entretanto, algo novo, mas durante a maior parte do tempo, a crítica identificou o ceticismo de Machado com a acepção popular do termo: descrença no campo metafísico e desengano no campo político-social. Este modo de ver o ceticismo acaba por aproximar o termo, e reaproximar Machado de Assis, ao pessimismo. Por outro lado, há algumas décadas, alguns estudiosos brasileiros começaram a verificar que a filosofia da ficção machadiana estaria de fato associada ao ceticismo, mas a outro tipo de ceticismo, o ceticismo pirrônico ou filosófico, iniciado com Pirro de Elis, filósofo grego que viveu entre 360 e 270 a.C., e estabelecido pelos escritos de Sexto Empírico, filósofo e médico do século 2. Fazendo jus à origem grega do termo skepticós, aquele que investiga, o ceticismo pirrônico prima não pela descrença, mas pela busca contínua da verdade. Esta busca se mantém indeterminada em virtude da limitação dos sentidos e do pensamento humanos. Não podemos alcançar a verdade das coisas, mas apenas descrever como elas aparentam. Esta impossibilidade não conduz o pirrônico ao pessimismo, o conduz, ao contrário, à tranquilidade, pois ele aceita a sua limitação, não fica se debatendo contra ela. Na ficção machadiana, o conselheiro Aires é o personagem cético por excelência, a começar pelo tão famoso tédio à controvérsia. Entretanto, apesar da semelhança entre a ficção de Machado de Assis e a filosofia cética, há um problema a ser enfrentado: como o escritor poderia ter criado um personagem tão próximo do pirronismo se Machado nunca chegou a ler uma página de Sexto Empírico? / Joaquim Maria Machado de Assis is the most important Brazilian fictionist, according to the critics and the academy. Together with its undeniable quality, his fiction is notable for its dimension, reaching ten novels and over two hundred short stories. Because of its unique union between quality and size, Machados work has garnered the biggest critical fortune among Brazilian writers and one of the greatest in literature all over the world. Still, his fortune is the fastest growing in Brazil. Faced with such dedication of the scholars, it would be relevant to present a new paper on the Warlock of Cosme Velho? Believing that some of the crucial aspects of his life and work have not been elucidated, despite of the size of the research that has been done on Machado, this work comes with the intention to contribute reducing this gap. One of these aspects is the philosophical content of Machado's fiction. For many decades, the idea that Machado de Assis is philosophically aligned with pessimism was hegemonic. However, many features of Machado's fiction, such as humour and irony, may be signs of other philosophical orientation: skepticism. However, the identification between Machado and skepticism is not something new. But during most of the time, the critics identified the skepticism of Machado with the popular sense of that word: disbelief concerning metaphysical dimension and disappointment concerning politics and social environment. This view of skepticism, however, approximates the term to pessimism; and reconnects Machado de Assis to it. Decades ago, some Brazilian scholars began to see that the philosophy of Machado's fiction was actually associated with skepticism, but another kind of skepticism, the Pyrrhonian or philosophical skepticism, which began with Pyrrho of Elis, a Greek philosopher who lived between 360 and 270 BC, and was established by the writings of Sextus Empiricus, philosopher and physician of the second century. True to the Greek origin of the term skepticos, the one who inquires, the Pyrrhonian skepticism is distinguished not by disbelief, but by its continual search for the truth. This search remains undetermined due to the limitation of human senses and thought. We cannot reach the truth of things, but only describe how they look. This failure does not lead the Pyrrhonian to pessimism, leads him instead to the tranquility, because he accepts his limitations and is not struggling against them. In Machado's fiction, counselor Aires is the skeptical character par excellence, starting with his famous aversion to controversy. However, despite the similarity between the fiction of Machado de Assis and skeptical philosophy, there is a problem to be faced: Machado had never read a single page from Sextus Empiricus. So, how could the writer created a so closed to the Pyrrhonism character?

Há um consenso nos meios crítico e acadêmico de que Joaquim Maria Machado de Assis é o maior ficcionista brasileiro. Além da qualidade inegável, sua ficção é notável por sua dimensão, atingindo uma dezena de romances e mais de duzentos contos. Com esta união singular entre extensão e qualidade, a obra machadiana acumulou a maior fortuna crítica no Brasil e uma das maiores da literatura universal. Ainda assim, sua fortuna é a que mais cresce no Brasil. Diante de tamanha dedicação dos estudiosos, em que seria relevante a apresentação de mais uma dissertação sobre o Bruxo do Cosme Velho? Acreditando que, apesar do tamanho da investigação que já se fez sobre Machado, alguns dos aspectos cruciais da vida e da obra do escritor ainda não foram devidamente elucidados, este trabalho nasce com a intenção de contribuir para a diminuição dessa lacuna. Um desses aspectos é o conteúdo filosófico da ficção machadiana. Durante muitas décadas, a ideia de que Machado de Assis se alinhara filosoficamente ao pessimismo foi hegemônica. Entretanto, muitas características da ficção machadiana, tais como o humour e a ironia, podem ser sinais de outra orientação filosófica: o ceticismo. A identificação entre Machado e ceticismo não é, entretanto, algo novo, mas durante a maior parte do tempo, a crítica identificou o ceticismo de Machado com a acepção popular do termo: descrença no campo metafísico e desengano no campo político-social. Este modo de ver o ceticismo acaba por aproximar o termo, e reaproximar Machado de Assis, ao pessimismo. Por outro lado, há algumas décadas, alguns estudiosos brasileiros começaram a verificar que a filosofia da ficção machadiana estaria de fato associada ao ceticismo, mas a outro tipo de ceticismo, o ceticismo pirrônico ou filosófico, iniciado com Pirro de Elis, filósofo grego que viveu entre 360 e 270 a.C., e estabelecido pelos escritos de Sexto Empírico, filósofo e médico do século 2. Fazendo jus à origem grega do termo skepticós, aquele que investiga, o ceticismo pirrônico prima não pela descrença, mas pela busca contínua da verdade. Esta busca se mantém indeterminada em virtude da limitação dos sentidos e do pensamento humanos. Não podemos alcançar a verdade das coisas, mas apenas descrever como elas aparentam. Esta impossibilidade não conduz o pirrônico ao pessimismo, o conduz, ao contrário, à tranquilidade, pois ele aceita a sua limitação, não fica se debatendo contra ela. Na ficção machadiana, o conselheiro Aires é o personagem cético por excelência, a começar pelo tão famoso tédio à controvérsia. Entretanto, apesar da semelhança entre a ficção de Machado de Assis e a filosofia cética, há um problema a ser enfrentado: como o escritor poderia ter criado um personagem tão próximo do pirronismo se Machado nunca chegou a ler uma página de Sexto Empírico? / Joaquim Maria Machado de Assis is the most important Brazilian fictionist, according to the critics and the academy. Together with its undeniable quality, his fiction is notable for its dimension, reaching ten novels and over two hundred short stories. Because of its unique union between quality and size, Machados work has garnered the biggest critical fortune among Brazilian writers and one of the greatest in literature all over the world. Still, his fortune is the fastest growing in Brazil. Faced with such dedication of the scholars, it would be relevant to present a new paper on the Warlock of Cosme Velho? Believing that some of the crucial aspects of his life and work have not been elucidated, despite of the size of the research that has been done on Machado, this work comes with the intention to contribute reducing this gap. One of these aspects is the philosophical content of Machado's fiction. For many decades, the idea that Machado de Assis is philosophically aligned with pessimism was hegemonic. However, many features of Machado's fiction, such as humour and irony, may be signs of other philosophical orientation: skepticism. However, the identification between Machado and skepticism is not something new. But during most of the time, the critics identified the skepticism of Machado with the popular sense of that word: disbelief concerning metaphysical dimension and disappointment concerning politics and social environment. This view of skepticism, however, approximates the term to pessimism; and reconnects Machado de Assis to it. Decades ago, some Brazilian scholars began to see that the philosophy of Machado's fiction was actually associated with skepticism, but another kind of skepticism, the Pyrrhonian or philosophical skepticism, which began with Pyrrho of Elis, a Greek philosopher who lived between 360 and 270 BC, and was established by the writings of Sextus Empiricus, philosopher and physician of the second century. True to the Greek origin of the term skepticos, the one who inquires, the Pyrrhonian skepticism is distinguished not by disbelief, but by its continual search for the truth. This search remains undetermined due to the limitation of human senses and thought. We cannot reach the truth of things, but only describe how they look. This failure does not lead the Pyrrhonian to pessimism, leads him instead to the tranquility, because he accepts his limitations and is not struggling against them. In Machado's fiction, counselor Aires is the skeptical character par excellence, starting with his famous aversion to controversy. However, despite the similarity between the fiction of Machado de Assis and skeptical philosophy, there is a problem to be faced: Machado had never read a single page from Sextus Empiricus. So, how could the writer created a so closed to the Pyrrhonism character?

The aim of this dissertation is to provide a critique of the idea that skepticism was the driving force in the development of early modern thought. Historian of philosophy Richard Popkin introduced this thesis in the 1950s and elaborated on it over the next five decades, and recent scholarship shows that it has become an increasingly accepted interpretation. I begin with a study of the relevant historical antecedents—the ancient skeptical traditions of which early modern thinkers were aware—Pyrrhonism and Academicism. Then I discuss the influence of skepticism on three pre-Cartesians: Francisco Sanches, Michel de Montaigne, and Pierre Charron. Basing my arguments on an informed understanding of both ancient Greek skepticism and some of the writings of these philosophers, I contend that it is inaccurate to predominantly characterize Sanches, Montaigne, and Charron as skeptics. To support his thesis about the singular influence of skepticism on early modern thought, Popkin says that René Descartes’ metaphysical philosophy was formed as a response to a skeptical threat and that Descartes ultimately conceded to the force of skepticism. He also argues that David Hume was a Pyrrhonist par excellence. I disagree with Popkin’s claims. I argue that Descartes was not as deeply affected by skepticism as Popkin suggests and that it is inaccurate to characterize Hume as a Pyrrhonist. By offering this critique, I hope to make clear to the readers two things: first, that Popkin’s thesis, though it is both enticing and generally accepted by many scholars, is questionable with regard to its plausibility; second, that the arguments I present in this dissertation reveal that further research into the role of skepticism in early modern philosophy is in order.

The following inquiry pursues two interlinked aims. The first is to understand Wittgenstein's idea of non-foundational certainty in the context of a reading of On Certainty that emphasizes its Pyrrhonian elements. The second is to read Wittgenstein's remarks on idealism/radical skepticism in On Certainty in parallel with the discussion of rule-following in Philosophical Investigations in order to demonstrate an underlying similarity of philosophical concerns and methods. I argue that for the later Wittgenstein, what is held certain in a given context of inquiry or action is a locally transcendental condition of the inquiry or action in question. In On Certainty, Wittgenstein's analysis of the difference between knowledge and certainty forms the basis of his critique of both Moore's "Proof" and radical skepticism. This critique takes the shape of rejection of a presupposition shared by both parties, and utilizes what I identify as a Pyrrhonian-style argument against opposed dogmatic views. Wittgenstein's method in this text involves describing epistemic language-games. I demonstrate that this is consistent with the rejection of epistemological theorizing, arguing that a Wittgensteinian "picture" is not a theory, but an impressionistic description that accomplishes two things: (i) throwing into relief problems with dogmatic theories and their presuppositions, and (ii) describing the provenance of linguistic and epistemic practices in terms of norms grounded in convention. Convention, in turn, is not arbitrary, but grounded in the biological and social natures of human beings--in what Wittgenstein calls forms of life. Thus there is a kind of naturalism in the work of the later Wittgenstein. It is a naturalism that comes neatly dovetailed with Pyrrhonism--a combination of strategies traceable to Hume's work in the Treatise. I read Hume as someone who develops the Pyrrhonian method to include philosophy done "in a careless manner," and argue that Wittgenstein adopts a similar method in his later works. Finally, I explain the deference to convention in the work of both Hume and Wittgenstein by reference to a passage in Sextus' Outlines, on which I provide a gloss in the final chapter of this work.

A tese defende a ideia de que uma compreensão adequada da suspensão cética de juízo (epokhé) pressupõe o estudo dos textos de Sexto Empírico que, direta ou indiretamente, abordam o problema da concepção pirrônica da linguagem ou discurso (lógos), e também daqueles que fornecem elementos para a compreensão da posição sextiana acerca da linguagem cotidiana das pessoas comuns. Os primeiros capítulos lidam com a conhecida distinção entre as assim chamadas interpretações rústica e urbana da filosofia pirrônica. A seguir, o texto discute o problema do lógos quando considerado a partir de uma perspectiva pirrônica, onde uma nova argumentação em favor da interpretação rústica é desenvolvida, baseada na ideia de um percurso cético. No quarto capítulo, é examinada a noção de phainómenon e sua relação com o lógos cético, através da formulação de uma interpretação mais geral do ceticismo antigo e do seu discurso fenomênico. O quinto e último capítulo procede então a uma avaliação da força filosófica tanto da filosofia pirrônica como da neopirrônica / The dissertation defends the idea that an adequate understanding of the sceptical suspension of judgement (epoché) presupposes the study of the Sextus Empiricus texts which, either directly or indirectly, address the problem of the pyrrhonian conception of language or discourse (lógos), and also the study of those texts that provide elements for the understanding of the Sextian position about the everyday language of common people. The first chapters deal with the well-known distinction between the so-called rustic and urbane interpretations of the pyrrhonian philosophy. In the sequence, the dissertation discusses the problem of the lógos, as viewed from a pyrrhonian perspective, also by developing a new argument in favor of the rustic interpretation, based upon the idea of a sceptic path. Subsequently, the notion of phainómenon and its relation to the sceptic lógos are analyzed through a general approach to ancient scepticism. The fith and last chapter proceeds to an avaluation of the philosophical strength of both the pyrrhonian and neopyrrhonian philosophies

Orientador: Marcus Vinicius da Cunha / Banca: Luiz Henrique de Araújo Dutra / Banca: Paula Ramos de Oliveira / Banca: Vera Teresa Valdemarin / Banca: Ana Raquel Lucato Cianflone / Resumo: O presente trabalho analisa as concepções filosóficas de John Dewey, tomando como principal referência o livro The quest for certainty: a study of the relation of knowledge and action, publicado em 1929, no qual o autor propõe utilizar o método das ciências experimentais no campo das ciências humanas, em especial para o exame dos juízos morais. Nesse livro, Dewey defende o rompimento da dicotomia entre teoria e prática e atribui caráter probabilístico aos conhecimentos advindos da investigação científica, tomando como exemplo a mecânica quântica. Os referenciais metodológicos empregados na análise do discurso deweyano advêm da nova retórica, teoria proposta por Chaïm Perelman e Lucie Olbrechts-Tyteca em Tratado da argumentação. O objetivo do trabalho é mostrar a proximidade entre Dewey e o ceticismo, tomando por base as concepções de Pirro de Élis sistematizadas por Enesidemo e Sexto Empírico, bem como desenvolvimentos recentes dessa filosofia. A intenção mais ampla do trabalho é contribuir para a discussão de teses que divergem em relação ao tema focalizado nesta pesquisa: de um lado, as que responsabilizam o ceticismo deweyano pelos males da educação contemporânea, e, de outro, as que atribuem a Dewey a origem de importantes progressos na pedagogia. / Abstract: The present study analyses the philosophical conceptions of John Dewey presented in the book The quest for certainty: a study of the relation of knowledge and action, published in 1929, in which the author proposes to use the method of experimental sciences in human sciences, specially to the examination of moral judgments. In this book, Dewey defends the disruption of the dichotomy between practical and theory and attributes a probabilistic character to the scientific inquiry knowledge, citing as an example the quantun mechanics. The methodology adopted to analyze deweyan discourse is the new rhetoric, based upon Treatise of argumentation by Chaïm Perelman and Lucie Olbrechts-Tyteca. The objective of the this work is to show to the proximity between Dewey and the skepticism, having as a basis the conceptions of Pyrrho from Élis systematized by Aenesidemus and Sextus Empiricus, as well as recent developments of this philosophy. The work also intends to contribute for the discussion of theses which diverge on the theme of this work: on the one hand, the ones that blame Dewey's skepticism for the harmfulness of contemporary education; and, on the other, those which attribute the origin of important progress in pedagogy to Dewey. / Doutor

Ancient Greek philosophical schools are said to share a common structure in their ethical theories which is characterized by a eudaimonistic teleology based in an understanding of human nature. At first glance, the skepticism of Sextus Empiricus as described in the Outlines of Pyrrhonism seems to fit into this model insofar as he describes the end of the skeptic as ataraxia, a common account of the expression of human happiness. I argue that this is a misunderstanding of Sextus’s philosophy for several reasons. “The end of skepticism” cannot be eudaimonistic or teleological in the way that other ancient ethical theories are typically understood; moreover, ataraxia is not an end derived from a theory about human nature. For these reasons, the skeptical way of life is radically different than the ethical theories proposed by other schools. I argue that this difference is a result of the character of the skeptical enterprise which involves the implicit rejection of norms in both the epistemological and the ethical spheres.

Made available in DSpace on 2014-06-11T19:31:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-08Bitstream added on 2014-06-13T18:42:13Z : No. of bitstreams: 1 costalopes_v_dr_arafcl.pdf: 362341 bytes, checksum: ae0f2fc12d277eed0383947607fbc4c0 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O presente trabalho analisa as concepções filosóficas de John Dewey, tomando como principal referência o livro The quest for certainty: a study of the relation of knowledge and action, publicado em 1929, no qual o autor propõe utilizar o método das ciências experimentais no campo das ciências humanas, em especial para o exame dos juízos morais. Nesse livro, Dewey defende o rompimento da dicotomia entre teoria e prática e atribui caráter probabilístico aos conhecimentos advindos da investigação científica, tomando como exemplo a mecânica quântica. Os referenciais metodológicos empregados na análise do discurso deweyano advêm da nova retórica, teoria proposta por Chaïm Perelman e Lucie Olbrechts-Tyteca em Tratado da argumentação. O objetivo do trabalho é mostrar a proximidade entre Dewey e o ceticismo, tomando por base as concepções de Pirro de Élis sistematizadas por Enesidemo e Sexto Empírico, bem como desenvolvimentos recentes dessa filosofia. A intenção mais ampla do trabalho é contribuir para a discussão de teses que divergem em relação ao tema focalizado nesta pesquisa: de um lado, as que responsabilizam o ceticismo deweyano pelos males da educação contemporânea, e, de outro, as que atribuem a Dewey a origem de importantes progressos na pedagogia. / The present study analyses the philosophical conceptions of John Dewey presented in the book The quest for certainty: a study of the relation of knowledge and action, published in 1929, in which the author proposes to use the method of experimental sciences in human sciences, specially to the examination of moral judgments. In this book, Dewey defends the disruption of the dichotomy between practical and theory and attributes a probabilistic character to the scientific inquiry knowledge, citing as an example the quantun mechanics. The methodology adopted to analyze deweyan discourse is the new rhetoric, based upon Treatise of argumentation by Chaïm Perelman and Lucie Olbrechts-Tyteca. The objective of the this work is to show to the proximity between Dewey and the skepticism, having as a basis the conceptions of Pyrrho from Élis systematized by Aenesidemus and Sextus Empiricus, as well as recent developments of this philosophy. The work also intends to contribute for the discussion of theses which diverge on the theme of this work: on the one hand, the ones that blame Dewey’s skepticism for the harmfulness of contemporary education; and, on the other, those which attribute the origin of important progress in pedagogy to Dewey.