O presente trabalho visa motivar e defender o disjuntivismo epistemológico, a tese de que a percepção é estado factivo e racionalmente fundado. Essa variação de disjuntivismo é apresentada como uma dissolução do paradoxo cético da subdeterminação. Diante do problema cético do sonho, o disjuntivismo epistemológico é tomado conjuntamente com uma concepção enactivista da percepção, cuja tese central é que estados perceptuais são constituídos pelas ações do agente no ambiente. A conjunção dessas duas teses promove uma concepção corporificada da racionalidade, segundo a qual estados percpetuais racionalmente fundados são obtidos pelo exercício de habilidades do indivíduo no ambiente. Essa tese é ameaçada pela intuição supostamente plausível de que indivíduos em cenários céticos poderiam ser racionais, ainda que não possuíssem meios corpóreos para interação com seu em torno. Argumenta-se contra essa intuição pela crítica à maneira como cenários céticos são concebidos. Por fim, aplica-se o enactivismo radical ao autoconhecimento, promovendo um meio termo entre um modelo perceptual de autoconhecimento e um modelo racionalista. / This work is intended to motivate and defend epistemological disjunctivism, the view that perception is a factive and rationally grounded state. This version of disjunctivism is presented as a dissolution of the underdetermination skeptical paradox. Facing the dream skeptical problem, epistemological disjunctivism is taken in conjunction with an enactive conception of perception, whose core thesis is that perceptual states are constituted by one’s actions in the environment. The conjunction of these two theses promotes an embodied notion of rationality, according to which rationally grounded perceptual states are achieved by the exercise of one’s abilities in the environment. That view is threatened by the apparently plausible intuition that individuals in skeptical scenarios could be rational even if they lacked the bodily means to interact with their surroundings. This intuition is defeated by a critique to the way skeptical scenarios are conceived. Lastly, radical enactivism is applied to self-knowledge, attaining a middle ground between the perceptual and the rationalist models of self-knowledge.

Au 20ème siècle, la position traditionnelle de l’épistémologie cartésienne a reçu de nombreuses critiques. La transparence de l’esprit et notre accès authentique à nos propres états mentaux sont couramment attaqués par les arguments selon lesquels nos jugements prétendument fondamentaux ne sont point infaillibles. Le problème de la « poule tachetée » proposé par Chisholm est ici un bon exemple. D’autres épistémologues ont proposé des scénarios où les cognitions fondamentales sont les victimes, soit des processus cognitifs étranges, soit des environnements défavorables. On a aussi constaté qu’il y a de cognitions fondamentales qui sont obscures ou fausses. Ces trois groupes d’objections faillibilistes ne sont pas irréfragables, mais il n’y a pas non plus de réponse systématique et suffisamment solide de la part de ceux qui défendent la thèse de l’infaillibilité fondamentale. Dans le présent travail, nous reconstruirons un modèle de l’intuition à l’inspiration des Regulae ad directionem ingenii. Nous réfuterons avec ce modèle la plupart des objections contemporaines, et proposerons en même temps une nouvelle interprétation des textes principaux de Descartes. / During the 20th century, the position of Cartesian epistemology has been much criticized. The transparency of the mind, as well as our authentic access to our own mental states, have been continuously attacked by arguments that attempt to reveal the fallibility of our putatively foundational cognitions. The famous problem of the speckled hen is representative; some epistemologists have also configured fictional scenarios where our foundational cognitions suffer from strange cognitive process or unfavorable epistemic environment, so that the relevant cognitions are no longer reliable, a fortiori infallible; others directly state that there are fundamental cognitions that are actually mistaken. These three groups of fallibilist objections are not flawless, but there are no systematic and sufficiently solid responses that defend the infallibility thesis either. In this dissertation, we shall reconstruct a model of intuition on the basis of Descartes’ Regulae ad directionem ingenii. The model will be used to refute most of the contemporary anti-Cartesian objections. It also provides a new interpretation of Descartes’ Meditations and other related texts.

nÃo hà / This thesis aims facing the skeptical argument classic type from the contrastivist knowledge theory. The problem we will approach is when we accept the epistemic logic principle called closing principle. The principle states that knowledge is closed under implication and seems to regulate the way we expand our ordinary knowledge. Basically the closure affirms that for every epistemic subject S, target proposition p and logic Contrary q, If S knows that p and S knows that p logically implies q, so S knows that q. The problem arises when the contrary logic is a skeptical hypothesis, a hypothesis we can't know. Operating a modus tollens in the beginning closure a skeptic concludes logically that we can't know anything. To contextualize the skeptical problem contrastive solution problem that makes uses of closing we will show two theories treatment that will serve as preliminaries. The first is Fred Dretske's Relevant Alternatives Theory and the secondd is David Lewis' Contextualism. Dretske acknowledged accepting closure means surrendering to skepticism, for this reason tried to solve the problem rejecting the closing validity. The Closure rejection by Dretske, however, was considered ad hoc, therefore, unable to solve the problem. David Lewis contextualist solution, however, accepts the closure principle validity and seeks problem resolution by accusing the skeptic of misunderstand as to semantic term know. For Lewis, "knowledge" is an indexical term and , as such, undergoes contextual (semantic and epistemic) variations. Understand adequately the knowledge indexicality, for the contextualist, will show the paradox is only apparent. We will show Lewis theory advantages, but we will also show that it is unsatisfactory to solve skepticism problem. We will defend, finally, that the theory that best accommodates ordinary knowledge against skeptical arguments is Jonathan Schaffer's Contrastivism. The contrastivist theory will look to dodge the problem appealing to an epistemic revisionism. For Schaffer, the knowledge relation is essentially ternary and when we look at the skeptic puzzle by contrastivist bias we will perceive the problem is mitigated, that is, it is weakened in a most intuitive way than Dretske and Lewis theories. The contrastivist theory will defend, in an innovative way, that ordinary knowledge is compatible with skeptical doubt. / Esta tese tem por objetivo enfrentar um tipo clÃssico de argumento cÃtico a partir da teoria contrastivista do conhecimento. O problema que abordaremos surge quando aceitamos o princÃpio de lÃgica epistÃmica chamado princÃpio de fechamento. O princÃpio afirma que o conhecimento à fechado sob implicaÃÃo e parece regular o modo como expandimos nosso conhecimento ordinÃrio. Basicamente o fechamento afirma que para todo sujeito epistÃmico S, proposiÃÃo alvo p e contrÃria lÃgica q, se S sabe que p e S sabe que p implica logicamente q, entÃo S sabe que q. O problema surge quando a contrÃria lÃgica à uma hipÃtese cÃtica, uma hipÃtese que nÃo podemos conhecer. Operando um modus tollens no princÃpio de fechamento o cÃtico conclui logicamente que nÃo podemos conhecer qualquer coisa. Para contextualizar a soluÃÃo contrastivista do problema cÃtico que faz uso do fechamento apresentaremos o tratamento de duas teorias que nos servirÃo de preliminares. A primeira à a Teoria das Alternativas Relevantes de Fred Dretske e a segunda à o Contextualismo de David Lewis. Dretske reconheceu que aceitar o fechamento significa se render ao ceticismo, por esta razÃo tentou resolver o problema rejeitando a validade do fechamento. A rejeiÃÃo do fechamento por Dretske, entretanto, foi considerada ad hoc e, por isso, incapaz de resolver o problema. A soluÃÃo contextualista de David Lewis, entretanto, aceita a validade do princÃpio do fechamento e busca resolver o problema acusando o cÃtico de equivocar-se quanto à semÃntica do termo conhecer. Para Lewis o âconhecimentoâ à um termo indexical e, como tal, sofre variaÃÃes (semÃnticas e epistÃmicas) contextuais. Compreender adequadamente a indexicalidade do conhecimento, para o contextualista, mostrarà que o paradoxo à apenas aparente. Mostraremos as vantagens da teoria de Lewis, mas mostraremos tambÃm que ela à insatisfatÃria para resolver o problema do ceticismo. Defenderemos, por fim, que a teoria que melhor acomoda o conhecimento ordinÃrio frente aos argumentos cÃticos à o Contrastivismo de Jonathan Schaffer. A teoria contrastivista buscarà esquivar-se do problema apelando para um revisionismo epistÃmico. Para Schaffer, a relaÃÃo de conhecimento à essencialmente ternÃria e quando olharmos para o puzzle cÃtico pelo viÃs contrastivista perceberemos que o problema à mitigado, ou seja, à enfraquecido de um modo mais intuitivo do que as teorias de Dretske e Lewis. A teoria contrastivista defenderÃ, de maneira inovadora, que o conhecimento ordinÃrio à compatÃvel com a dÃvida cÃtica.

Neste trabalho, desenvolvemos uma discussão sobre a relação entre ceticismo e filosofia no idealismo alemão, notadamente em Hegel. Em particular, no interessa o papel que essa relação desempenha no problema da autodeterminação racional, problema que, a nosso ver, é central para o projeto de filosofia moderna adotado pelos autores do idealismo alemão, e de grande importância para a sua compreensão. Pretendemos mostrar como a confrontação dos autores deste período com os céticos, em particular com Hume, Schulze, Maimon e Sexto Empírico, desempenha um papel central na formação de suas concepções sobre a filosofia, sobre tarefa desta e sobre como ela poderia realizar essa tarefa apenas pela incorporação do ceticismo. Mais do que isso, visamos a mostrar como a confrontação com o ceticismo será fundamental para o desdobramento da concepção que os idealistas alemães têm da autodeterminação racional já que seria como resposta ao ceticismo que eles veriam a necessidade de desenvolver mais profundamente essa concepção do que os seus predecessores haviam o feito o que ajudaria a explicar porque, de um projeto crítico baseado na determinação dos limites do entendimento humano, passamos para filosofias segundo as quais toda filosofia tem que e só pode começar pelo absoluto. Esperamos contribuir para a compreensão desses importantes filósofos do idealismo alemão, bem como para a compreensão do ceticismo, mostrando como essas duas formas de filosofia podem se enriquecer mutuamente por meio do debate em torno do problema da autodeterminação racional. / In this work, we attempt to discuss the relationship between skepticism and philosophy in german idealism, specially in Hegel. We are particularly interested in the role this relationship plays in the problem of rational self-determination, which, as we see it, lies at the core of the project of modern philosophy adopted by the authors of german idealism, and is of great importance for their comprehension. We aim to show how the confrontation of authors of this period with the skeptics, in particular with Hume, Schulze, Maimon and Sextus Empiricus, has an important role in the constitution of their conceptions of philosophy, its task and how it could accomplish said task. Moreover, we will attempt to show that the confrontation with skepticism is fundamental for the development of the conception of rational self-determination held by the german idealists, since it is as an answer to skepticism that they find it necessary to develop this conception further than it had been done by their predecessors which would help explain why, from a critical project of determining the limits of human understanding, we go to philosophies to which all philosophies must start with the absolute. We hope to contribute to the comprehension of these important philosophers of german idealism, as well as to the comprehension of skepticism, by showing how these two forms of philosophy can mutually enrich each other through the debate around the rational self-determination problem.

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

This PhD thesis provides an extended evaluation of evolutionary debunking arguments in meta-ethics. Such arguments attempt to show that evolutionary theory, together with a commitment to robust moral objectivity, lead to moral scepticism: the implausible view that we lack moral knowledge or that our moral beliefs are never justified (e.g. Joyce 2006, Street 2005, Kahane 2011). To establish that, these arguments rely on certain epistemic principles. But most of the epistemic principles appealed to in the literature on evolutionary debunking arguments are imprecise, confused or simply implausible. My PhD aims to rectify that. Informed by debates in cutting-edge contemporary epistemology, Chapter 1 distinguishes three general, independently motivated principles that, combined with evolution, seem to render knowledge of robustly objective moral facts problematic. These epistemic principles state that (i.) our getting facts often right in a given domain requires explanation - and if we cannot provide one, our beliefs about that domain are unjustified; (ii.) higher-order evidence of error undermines justification; and (iii.) for our beliefs to be justified, our having them must be best explained by the facts they are about. Chapters 2-4 develop and critically assess evolutionary debunking arguments based on those principles, showing that only the one inspired by (iii.) succeeds. Chapter 2 investigates the argument that evolution makes explaining why we get moral facts often right impossible. I argue that Justin Clarke-Doane's recent response (2014, 2015, 2016, 2017) works, yet neglects an issue about epistemic luck that spells trouble for robust moral objectivity. Chapter 3 discusses the argument that evolution provides higher-order evidence of error regarding belief in robustly objective moral facts. I show that such an argument falls prey to Katia Vavova's (2014) self-defeat objection, even if evolutionary debunkers tweak their background view on the epistemic significance of higher-order evidence. Chapter 4 develops the argument that evolution, rather than robustly objective moral facts, best explains why we hold our moral beliefs. I offer a systematic, comprehensive defence of that argument against Andreas Mogensen's (2015) charge of explanatory levels confusion, Terrence Cuneo's (2007) companion in guilt strategy, and David Enoch's (2012, 2016) appeal to deliberative indispensability. Chapter 5 brings everything together. It investigates whether robust moral objectivity survives the worry about epistemic luck raised in Chapter 2 and the explanatory challenge developed in Chapter 4. Making progress, however, requires a better idea of how we form true, justified beliefs about and acquire knowledge of robustly objective moral facts. Since it offers the most popular and best-developed epistemology of robustly objective morality, my inquiry in Chapter 5 focuses on contemporary moral intuitionism: the view that moral intuitions can be the source of basic moral knowledge. I argue that its success is mixed. While moral intuitionism has the conceptual tools to tackle the problem of epistemic luck from Chapter 2, it cannot insulate knowledge of robustly objective moral facts against the sceptical worry raised by the evolutionary debunking argument developed in Chapter 4. Thus, evolutionary theory, together with a commitment to robust moral objectivity, does lead to a form of unacceptable moral scepticism.

Há geralmente duas maneiras de se estudar o ceticismo de Hume: aproximando-o dos céticos pirrônicos, apesar dos seus protestos, ou aproximando-o dos acadêmicos, seguindo a recomendação do próprio autor. Entretanto, existe outra maneira de compreendermos o seu ceticismo, que consiste em avaliar em que medida Hume se aproxima de cada escola cética, e em que sentido se distancia delas. Para este propósito, nada melhor do que tentar compreender o ceticismo de Hume comparando as suas concepções com as de outros céticos do período em que ele viveu. A tese tem por finalidade realizar este confronto, a fim de contribuir para a interpretação do ceticismo moderno e sugerir uma maneira de aproximá-lo do ceticismo de Hume. / In general, there are two ways to study Humes skepticism: comparing his ideas to Pyrrhonic skeptic, in spite of his disapproval, and comparing him to academic philosophers, following the authors recommendations. However, there is another way to interpret Humes skepticism, namely, evaluating how he differs from Pyrrhonic and academician philosophers. The better approach is to compare Humes skepticism to other skepticss conceptions of Humes age. The main goal of the present thesis is put in evidence these approaches to understanding modern skepticism and, specifically, a way to compare it to Humes skepticism.

In this dissertation, we explore and illustrate the concept of ranked sparsity, a phenomenon that often occurs naturally in the presence of derived variables. Ranked sparsity arises in modeling applications when an expected disparity exists in the quality of information between different feature sets. Its presence can cause traditional model selection methods to fail because statisticians commonly presume that each potential parameter is equally worthy of entering into the final model - we call this principle "covariate equipoise". However, this presumption does not always hold, especially in the presence of derived variables. For instance, when all possible interactions are considered as candidate predictors, the presumption of covariate equipoise will often produce misclassified and opaque models. The sheer number of additional candidate variables grossly inflates the number of false discoveries in the interactions, resulting in unnecessarily complex and difficult-to-interpret models with many (truly spurious) interactions. We suggest a modeling strategy that requires a stronger level of evidence in order to allow certain variables (e.g. interactions) to be selected in the final model. This ranked sparsity paradigm can be implemented either with a modified Bayesian information criterion (RBIC) or with the sparsity-ranked lasso (SRL). In chapter 1, we provide a philosophical motivation for ranked sparsity by describing situations where traditional model selection methods fail. Chapter 1 also presents some of the relevant literature, and motivates why ranked sparsity methods are necessary in the context of interactions. Finally, we introduce RBIC and SRL as possible recourses. In chapter 2, we explore the performance of SRL relative to competing methods for selecting polynomials and interactions in a series of simulations. We show that the SRL is a very attractive method because it is fast, accurate, and does not tend to inflate the number of Type I errors in the interactions. We illustrate its utility in an application to predict the survival of lung cancer patients using a set of gene expression measurements and clinical covariates, searching in particular for gene-environment interactions, which are very difficult to find in practice. In chapter 3, we present three extensions of the SRL in very different contexts. First, we show how the method can be used to optimize for cost and prediction accuracy simulataneously when covariates have differing collection costs. In this setting, the SRL produces what we call "minimally invasive" models, i.e. models that can easily (and cheaply) be applied to new data. Second, we investigate the use of the SRL in the context of time series regression, where we evaluate our method against several other state-of-the-art techniques in predicting the hourly number of arrivals at the Emergency Department of the University of Iowa Hospitals and Clinics. Finally, we show how the SRL can be utilized to balance model stability and model adaptivity in an application which uses a rich new source of smartphone thermometer data to predict flu incidence in real time.

Thesis (Ph. D.)--Ohio State University, 2006. / Full text release at OhioLINK's ETD Center delayed at author's request

The aim of the present study is to develop a solution to the problem of skepticism about the external world ("skepticism", for short), inspired primarily by Hume's "skeptical solution" to the problem of skepticism about induction, but also by epistemological externalism and Wittgenstein's discussion of skeptical doubts in On Certainty. The author accepts certain elements in P. F. Strawson's interpretation of Hume and Wittgenstein, but rejects the "psychological" argument against skepticism which Strawson ascribes to the two philosophers. The problem of skepticism is understood as that of showing that we can know what we in common sense claim to know about external objects, despite skeptical arguments to the contrary. A "moderate" skepticism is accepted, according to which it is possible that we are globally mistaken in our beliefs about external objects, and it is argued that there is in fact no conflict between this moderate skepticism and common sense. A distinc-tion is drawn between two types of "strong" skepticism, which does conflict with common sense: prescriptive skepti-cism, the recommendation to abandon our common sense ways of forming beliefs, by suspend-ing judgement or in other ways; and theoretical skepti-cism, the thesis that we can have no rational grounds for our beliefs about external objects. An argument against prescriptive skepticism is devel-oped, according to which each of three possible forms of prescriptive skepticism is unacceptable. An externalist argument against theoreti-cal skepticism is developed, according to which it is suffi-cient for knowledge that one is in fact not globally mis-taken, whether or not one has grounds for believing this to be the case. It is argued that this variant of externalism constitutes a form of natu-ralistic epistemology, and that it as such fills a gap in Quine's argument for the natu-ralization of epistemology. An interpretation of On Certainty is defended, according to which Wittgen-stein accepts a form of moderate skepticism and presents an argu-ment against strong skep-ticism similar to Hume's.