Books by Daniel Durante Pereira Alves
PPGFIL-UFRN, 2022
Livro de Introdução à lógica, de autoria coletiva, distribuição livre e edição dinâmica, baseado ... more Livro de Introdução à lógica, de autoria coletiva, distribuição livre e edição dinâmica, baseado no livro forallx: Calgary.
Para que servem o bem, a beleza, o amor? Para que serve a felicidade? Para nada. Para absolutamen... more Para que servem o bem, a beleza, o amor? Para que serve a felicidade? Para nada. Para absolutamente nada. A filosofia é tão imprestável quanto as melhores coisas da vida, tão inútil quanto a felicidade, ou uma brincadeira de criança, ou um rabisco na areia deixado por alguém que passou raspando um graveto no chão sem olhar para trás. O impulso que nos move até ela é o mesmo que empurra o alpinista mais um passo para cima, ou os namorados mais um centímetro para perto, ou as crianças para mais um salto na corda. Este pequeno livro não é um tratado de filosofia, mas apenas um convite à alegria de pensar e especular sobre o mundo a nossa volta. Seu autor é um filósofo que não só acha inútil a filosofia, como além disso está aqui em suas horas vagas, divertindo-se com temas sérios, e convidando você a divertir-se também com reflexões filosóficas imprestáveis, porque a utilidade só é valor para o que não se basta.
The main objective of this PhD Thesis is to present a method of obtaining strong normalization vi... more The main objective of this PhD Thesis is to present a method of obtaining strong normalization via natural ordinal, which is applicable to natural deduction systems and typed lambda calculus. The method includes (a) the definition of a numerical assignment that associates each derivation (or lambda term) to a natural number and (b) the proof that this assignment decreases with reductions of maximal formulas (or redex). Besides, because the numerical assignment used coincide with the length of a specific sequence of reduction - the worst reduction sequence - it is the lowest upper bound on the length of reduction sequences. The main commitment of the introduced method is that it is constructive and elementary, produced only through analyzing structural and combinatorial properties of derivations and lambda terms, without appeal to any sophisticated mathematical tool. Together with the exposition of the method, it is presented a comparative study of some articles in the literature that also get strong normalization by means we can identify with the natural ordinal methods. Among them we highlight Howard[1968], which performs an ordinal analysis of Godel’s Dialectica interpretation for intuitionistic first order arithmetic. We reveal a fact about this article not noted by the author himself: a syntactic proof of strong normalization theorem for the system of typified lambda calculus λ⊃ is a consequence of its results. This would be the first strong normalization proof in the literature. (written in Portuguese)
Papers by Daniel Durante Pereira Alves
Disagreement over what exists is so fundamental that it tends to hinder or even to block dialogue... more Disagreement over what exists is so fundamental that it tends to hinder or even to block dialogue among disputants. The various con- troversies between believers and atheists, or realists and nominalists, are only two kinds of examples. Interested in contributing to the intelligibility of the debate on ontology, in 1939 Willard van Orman Quine began a series of works which introduces the notion of ontological commitment and proposes an allegedly objective criterion to identify the exact conditions under which a theoretical discourse signals an assumption of existence. I intend to present the concept of ontological commitment and the Quinean criterion, to expose and evaluate some of the many criticisms to which the criterion has subject and to situate it in the context of Quine’s philosophy. As a product of such analyses, I hope to contribute to the discussion on the application and relevance of the notion of ontological commitment.
Much of the ontology made in the analytic tradition of philosophy nowadays is founded on some of ... more Much of the ontology made in the analytic tradition of philosophy nowadays is founded on some of Quine's proposals. His naturalism and the binding between existence and quantification are respectively two of his very influential metaphilo-sophical and methodological theses. Nevertheless, many of his specific claims are quite controversial and contemporaneously have few followers. Some of them are: (a) his rejection of higher-order logic; (b) his resistance in accepting the intensional-ity of ontological commitments; (c) his rejection of first-order modal logic; and (d) his rejection of the distinction between analytic and synthetic statements. I intend to argue that these controversial negative claims are just interconnected consequences of those much more accepted and apparently less harmful metaphilosophical and methodological theses, and that the glue linking all these consequences to its causes is the notion of extensionality.
Analyzing the position of two philosophers whose views are recognizably divergent, W. O. Quine an... more Analyzing the position of two philosophers whose views are recognizably divergent, W. O. Quine and M. Dummett, we intend to support a striking point of agreement between them: the idea that our logical principles constitute our principles about what there is, and therefore, that logic is metaphysics.
Disagreements over what exists are so basic that they tend to hinder or even block the dialog bet... more Disagreements over what exists are so basic that they tend to hinder or even block the dialog between antagonists. The various disputes between believers and atheists, or realists and nominalists are only two kinds of examples. Interested in contributing to the intelligibility of the debate on ontology, W. V. Quine in 1939 began a series of works in which he presents the notion of ontological commitment and proposes a supposedly objective criterion to identify the exact conditions under which a theoretical discourse signals an assumption of existence. I intend to present the concept of ontological commitment and the quinean criterion, to present and evaluate some of the many criticisms that the criterion received and to situate it in the context of the philosophy of Quine. As a product of these analyses, I hope to contribute to the reflection on the relevance and philosophical place of the notion of ontological commitment.
É bem conhecida a divergência entre as posições de Gottlob Frege e Bertrand Russell com relação a... more É bem conhecida a divergência entre as posições de Gottlob Frege e Bertrand Russell com relação ao tratamento semântico dado a sentenças contendo termos singulares indefinidos, ou seja, termos singulares sem referência ou com referência ambígua, tais como 'Papai Noel' ou 'o atual rei da França' ou ' 1 0 ' ou ' √ 4'. Para Frege, as sentenças da linguagem natural que contêm termos indefinidos não formam de-clarações e portanto não são nem verdadeiras nem falsas. Já para as sentenças da matemática, Frege defende que elas precisam ser corrigidas através da convenção forçada de uma referência não ambígua. Russell, por outro lado, aceita os termos indefinidos e propõe, através de sua teoria das descrições definidas, uma maneira de avaliar as sentenças em que eles ocorrem; e Quine amplia a teoria de Russell para abranger também os nomes com problemas de referência. Na prática da mate-mática são comuns os termos singulares indefinidos, sem referência, tais como ' 1 0 ', ou com referência ambígua, tais como ' √ 4'. Apesar de não haver uma sistematiza-ção rigorosa desta situação entre os matemáticos, há, no entanto, um conjunto de regras convencionais que tradicionalmente costumam ser aplicadas no tratamento matemático dos termos indefinidos. Nossa proposta é tomar a convenção matemá-tica como inspiração e modelo para apresentar uma interpretação semântica formal para as descrições definidas e os nomes e utilizá-la como um argumento que favo-rece a abordagem de Russell relativamente à de Frege.
Besides answering the title question, my purpose with this essay is to present the outlines of an... more Besides answering the title question, my purpose with this essay is to present the outlines of an alternative way that has been proposed by some thinkers, on how our conception of science could be modified, so that it would help us to solve our main problems. In order to do that, I begin explaining what I see as the most fundamental characteristics of hegemonic scientific rationality, namely atomism and the axiomatic method. Then I present some known issues of this conception of science, showing its relations with these fundamental characteristics. Such problems are as much epistemological and methodological, closed to the knowledge itself, as much as they are ethical and related to its consequences. Then I set that the strong interconnection of these two types of problems can be better explained when we understand science in a instrumental way, as a response to a former interest for manipulation and control. Finally, based on the recognition of this contingent and socially constructed character of scientific knowledge, I answer the title question and indicate some possible methodological modifications to scientific practice that have been proposed in recent years. In particular, I present those that were labeled of complexity, transdisciplinarity, and methodological pluralism, indicating some issues and possible lines of research that these approaches raise.
Parece um fato bastante trivial que quando uma teoria científica se torna obsoleta, por ter sido ... more Parece um fato bastante trivial que quando uma teoria científica se torna obsoleta, por ter sido substituída por outra, isto não tem nenhuma consequência para os objetos técnicos compatíveis com a teoria antiga. Pretendo, neste ensaio, responder à questão bem menos óbvia de por que isto se dá. Como subproduto, apresento uma defesa da teoria da ciência de Thomas Kuhn. Para tanto, inicio mostrando como a teoria de Kuhn foi motivada por considerações sobre a história da ciência. Em seguida, defendo um pressuposto sobre como se dá a relação entre ciência e tecnologia. Continuo apresentando uma distinção entre conteúdo factual e conceitual na ciência. Por fim utilizo esta distinção e o pressuposto sobre a relação entre ciência e tecnologia para elaborar tanto a resposta à questão título quanto concluir o argumento em defesa da teoria da ciência de Kuhn.
Este ensaio propõe que o método da análise de conceitos, na versão apresentada por John Wilson, s... more Este ensaio propõe que o método da análise de conceitos, na versão apresentada por John Wilson, seja o principal método para o ensino da Filosofia no ensino médio e trata de algumas questões que o emprego do método envolve, principalmente a questão da possibilidade de tratamento dos principais problemas filosóficos a revelia dos textos dos próprios filósofos que os estudaram ao longo da história. O ensaio defende que esta é uma abordagem perfeitamente possível para a filosofia no ensino médio.
Este artigo, de divulgação, trata da relação entre ciência e determinismo. Procura explicar o mod... more Este artigo, de divulgação, trata da relação entre ciência e determinismo. Procura explicar o modo como o conhecimento científico, ainda que aumente nosso poder de manipulação e controle sobre a natureza, não será jamais instrumento para fortalecer pretensões deterministas e fatalistas.
Ciência & Educação (Bauru), 2013
Talks by Daniel Durante Pereira Alves
Quine was one of the greatest philosophers of the twentieth century. Some of his ideas are among ... more Quine was one of the greatest philosophers of the twentieth century. Some of his ideas are among the most influential in the analytic tradition of philosophy. His version of naturalism and the link between existence and quantification are two good examples. But Quine is also a very controversial philosopher, and many of his more specific negative theses do not have many supporters today. Some of them are the rejection of higher order logics; the rejection of modal first-order logic; the rejection of the analytic-synthetic distinction. I intend, in favor of Quine, defend the coherence of his philosophical conceptions, arguing that his most controversial positions are mere consequences of his most influential ones. Whoever accepts the influential ones should also accept the controversial ones. Furthermore, I intend, now against Quine, to argue that his most influential theses are less defensible than they appear to be. To this end I intend to show that attachment to these theses forced him to reduce the importance of his notion of ontological commitment and to adopt a position of ontological indifference.
Analyzing the position of two philosophers whose views are recognizably diver- gent, W. O. Quine ... more Analyzing the position of two philosophers whose views are recognizably diver- gent, W. O. Quine and M. Dummett, we intend to support a striking point of agreement between them: the idea that our logical principles constitute our principles about what there is, and therefore, that logic is metaphysics.
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Books by Daniel Durante Pereira Alves
Papers by Daniel Durante Pereira Alves
Talks by Daniel Durante Pereira Alves