Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The identification and analysis of epistemic principles have enabled significant gains in the study of skepticism in recent decades; this does not mean that we are near a consensus about which principles should be accepted. Taking p for any proposition that we normally accept to be known, like here is a hand , and h for a skeptical scenario such p is not true, but just a illusion projected in my mind , the skeptical argument can be formalized as follows: (1) If S knows that p, then S knows that ~h; (2) S doesn t know that ~h, then (3) S doesn t know that p. The first chapter of this text presents a comprehensive analysis of this argument, where is pointed out that its cogency can be defended from a valid version of the epistemic closure principle. The second chapter deals with the antiskeptical strategy advocated by Fred Dretske, which attempts to refute the skeptic arguing against its first premise, by rejecting the closure principle. At the end of this chapter, it is argued that the Dretske's arguments fail to fulfill their goal, collapsing in the face of relevant objections. Finally, the third chapter examines the answer to the skeptic presented by Peter Klein. Based on a more sophisticated understanding of the epistemic closure principle, Klein suggests that the skeptic cannot build a plausible argument for (2). It is argued that this analysis of the problem is adequate and resists criticism of his objectors. / A identificação e a análise de princípios epistêmicos têm possibilitado ganhos significativos no estudo do ceticismo nas últimas décadas; contudo isso não significa que estejamos próximos de um consenso sobre quais princípios devam ser aceitos. Entendendo p como qualquer proposição que geralmente admitiríamos saber, como aqui há uma mão , e h como algum cenário cético incompatível com a verdade de p, tal como p não é verdade mas apenas uma ilusão projetada em minha mente , o argumento cético é comumente assim formalizado: (1) Se S sabe que p, então S sabe que ~h; (2) S não sabe ~h, logo, (3) S não sabe que p. O primeiro capítulo desta dissertação é destinado à análise detalhada das premissas desse argumento, onde é apontado que sua cogência pode ser mantida a partir da defesa de uma versão válida do princípio de fechamento epistêmico. O segundo capítulo trata da estratégia anticética defendia por Fred Dretske, que busca refutar o ceticismo atacando sua primeira premissa, rejeitando o princípio de fechamento. Ao término deste capítulo, é defendido que os argumentos de Dretske falham no cumprimento de seu objetivo, sucumbindo frente a importantes objeções. Finalmente, no terceiro capítulo, discorre-se sobre a resposta para o cético apresentada por Peter Klein. Partindo de uma compreensão mais sofisticada do princípio de fechamento epistêmico, Klein sinaliza que o cético não consegue construir um argumento plausível para (2). Defende-se que essa análise do problema é adequada e resiste às críticas de seus objetores.

History is descriptive. Epistemology is conceived as normative. It appears, then, that a historical approach to epistemology, like historical epistemology, might not be epistemically normative. In our context here, epistemology is not a systematic theory of knowledge, truth, or justification. In this thesis I approach epistemic justification through the vantage point of practice of science. Practice is about reasoning. Reasoning, conceived as the human propensity to order perceptions, beliefs, memories, etc., in ways that permit us to have understanding, is not only about thinking. Reasoning has to do with our actions, too: In the ordering of reasoning we take into account the desires of ourselves and others. Reasoning has to do with tinkering with stuff, physical or abstract. Practice is primarily about skills. Practices are not mere groping. They have a form. Performing according to a practice is an activity with a lot of plasticity. The skilled performer retains the form of the practice in many different situations. Finally, practices are not static in time. Practices develop. People try new things, some of which may work out, others not. The technology involved in how to go about doing things in a particular practice changes, and the concepts concerning understanding what one is doing also may change. This is the point where history enters the picture. In this thesis I explore the interactions between history, reasoning, and skills from the viewpoint of a particular type of epistemic justification: a priori justification. An a priori justified proposition is a proposition which is evident independent of experience. Such propositions are self-evident. We will make sense of a priori justification in a context of regarding science as practice, so that we will be able to demonstrate that the latter accommodates the normative character of science.

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Il est souvent arrivé que, par le passé, les scientifiques affirment l'existence d'objets inobservables dont ils rejettent aujourd'hui l'existence. Quelle leçon tirer de ce fait ? On est tenté d'en conclure que les méthodes qu'emploient les scientifiques pour connaître l'inobservable ne sont pas fiables, de sorte que cette connaissance serait située hors de leur portée. Cette thèse identifie et rejette deux présupposés qui conduisent à cette conclusion, à savoir que la méthode de l'hypothèse serait la seule manière de produire des connaissances des inobservables, et que cette méthode se déploierait de manière instantanée. Si, au contraire, les modalités concrètes de l'activité expérimentale et la dimension diachronique de la recherche théorique sont prises en compte, chacun de ces deux présupposés doit être rejeté comme abstrait. La connaissance des effondrements théoriques passés légitime alors la croyance en la vérité des théories actuelles. / History of science presents us with numerous cases in which scientists conclude that an unobservable entity previously posited as real actually does not exist. What the lesson is to be drawn from this fact ? One is tempted to draw the conclusion that the methods employed by scientists to produce knowledge of unobservable objects are not reliable: gaining this knowledge would be beyond their reach. This thesis identifies and rejects two presuppositions that lead to this conclusion: that the method of hypothesis is the only way to produce knowledge of unobservables and that it can be employed in an instantaneous manner. On the contrary, if the concrete modalities of the experimental activity and the diachronical dimension of theoretical research are taken into account, each of these two presuppositions appear to be too abstract and should be rejected. Knowledge of past theoretical collapses then legitimates the belief in the truth of current scientific theories.

No description available.

Först presenteras metafysisk funktionalism. En Ramseysats för smärta spelar en central roll som en implicit definition av ett mentalt tillstånd över sensorisk input och beteendemässig output. Därefter presenteras reliabilismen som en teori om kunskap. Några allmänna kunskapsteoretiska problem, samt några av reliabilismens problem presenteras. De mest relevanta problem är följande: fallet med en elak demon, klärvoajans samt Mr. Truetemp, och generalitetsproblemet. En formell och schematisk presentation ges för reliabilism som en teori för kunskap, eller möjligen tillskrivande av kunskap, och processreliabilism som en teori för epistemiskt rättfärdigande. Därefter exponeras strukturella likheter mellan funktionalism och processreliabilism. Det får anses plausibelt att det råder ett nära släktskap mellan dessa teorier då Ramseysatser för rättfärdigade trosföreställningar presenteras. Dessa analyseras sedan utifrån möjliga fall. Med ny teoretisk bakgrund prövas reliabilismens problem ånyo inom ett funktionalistisk ramverk. Nya sätt att bemöta problemen presenteras genom en analys av det Kinesiska Rummet. Det svårlösta generalitetsproblemet kan ses som ett frameproblem och hanteras med hjälp av enveloping. / Firstly, a presentation of metaphysical functionalism. A Ramsey sentence plays a central role as an implicit definition of a mental state over sensory input and behavouristic output. A presentation of reliabilism as a theory of knowledge. A summary of some general epistemological problems and some specific to reliabilism; the main ones are the evil demon, clairvoyance and Mr. Truetemp, and the generality problem. A formal and schematic presentation of reliabilism as a theory of knowlege, or possibly knowlege attribution, and process reliabilism as a theory of belief justification. Structural similarities between functionalism and process reliabilism are exposed. A close kinship between these two theories seems plausible because of the possibility to present Ramsey sentences for justified beliefs. These Ramsey sentences are then analysed over possible cases. This new theoretical background, warrents another look at problems for reliabilism. New ways to counter these problems are presented via an analysis of the Chinese Room. The elusive genrality problem is seen as a frame problem and treated using enveloping.