De Cock and Kerre, in considering Poincaré paradox, observed that the intuitive notion of "approximate similarity" cannot be adequately represented by the fuzzy equivalence relations. In this note we argue that the deduction apparatus of fuzzy logic gives adequate tools with which to face the question. Indeed, a first-order theory is proposed whose fuzzy models are plausible candidates for the notion of approximate similarity. A connection between these structures and the point-free metric spaces is also established.

Poincaré in a 1909 lecture in Göttingen proposed a solution to the apparent incompatibility of two results as viewed from a definitionist perspective: on the one hand, Richard’s proof that the definitions of real numbers form a countable set and, on the other, Cantor’s proof that the real numbers make up an uncountable class. Poincaré argues that, Richard’s result notwithstanding, there is no enumeration of all definable real numbers. We apply previous research by Luna and Taylor on Richard’s (...) paradox, indefinite extensibility and unrestricted quantification to evaluate Poincaré’s proposal. We emphasize that Poincaré’s solution involves an early recourse to indefinite extensibility and argue that his proposal, if it is to completely avoid Richard’s paradox, requires rejecting absolutely unrestricted quantification: Richard’s paradox provides a context in which paradox seems inescapable if unrestricted quantification is possible. In proposing his solution to the apparent conflict between Richard’s and Cantor’s results, Poincaré employs temporal expressions whose exact meaning he does not clarify. We suggest an interpretation of these expressions in terms of order of availability and briefly discuss its explanatory power in topics like paradoxes, limitation theorems and indefinite extensibility. (shrink)

In 1905, Richard discovered his paradox of definability, and in a letter written that year he presented both the paradox and a solution to it.Soon afterwards, Poincaré endorsed a variant of Richard?s solution.In this paper, I critically examine Richard?s and Poincaré?s ways out.I draw on an objection of Peano?s, and argue that their stated solutions do not work.But I also claim that their writings suggest another way out, different from their stated solutions, and different from the (...) orthodox Tarskian approach.I argue that this second solution does not prevent the return of the paradox. (shrink)

A central theme in the foundational debates in the early Twentieth century in response to the paradoxes was to invoke the notion of the indefinite extensibility of certain concepts e,g. definability (the Richard paradox) and class (the Zermelo-Russell contradiction). Dummett has recently revived the notion, as the real lesson of the paradoxes and the source of Frege's error in basic law five of the Grundgesetze. The paper traces the historical and conceptual evolution of the concept and critices Dummett's argument (...) that the proper lesson of the paradoxes is that set theory is a theory of indefinitely extensible domains. (shrink)

A central theme in the foundational debates in the early Twentieth century in response to the paradoxes was to invoke the notion of the indefinite extensibility of certain concepts e,g. definability and class. Dummett has recently revived the notion, as the real lesson of the paradoxes and the source of Frege's error in basic law five of the Grundgesetze. The paper traces the historical and conceptual evolution of the concept and critices Dummett's argument that the proper lesson of the paradoxes (...) is that set theory is a theory of indefinitely extensible domains. (shrink)

When Henri Poincaré reviewed the then competing theories of electrodynamics in the 1890s, he required their compatibility with two principles of mechanical origin—the reaction principle and the relativity principle. Historians of relativity theory have usually focused on the relativity principle and neglected or misinterpreted Poincaré’s concern with the reaction principle. In particular, most of them have interpreted his crucial article of 1900 on “Lorentz’s theory and the principle of reaction” as an attempt to save this principle by assuming (...) an electromagnetic momentum in addition to the momentum of matter. The purpose of this article is to dismiss this interpretation and show that Poincaré had the opposite intention as he spelled out the paradoxical consequences of Lorentz’s violation of the reaction principle. In doing so, he formally introduced a quantity that could later be interpreted as a genuine electromagnetic momentum, developed a fundamentally new understanding of Lorentz’s transformations in relation with the relativity principle and identified the paradoxes that Einstein would later solve by assuming the inertia of energy. (shrink)

In (Weaver 2021), I showed that Boltzmann’s H-theorem does not face a significant threat from the reversibility paradox. I argue that my defense of the H-theorem against that paradox can be used yet again for the purposes of resolving the recurrence paradox without having to endorse heavy-duty statistical assumptions outside of the hypothesis of molecular chaos. As in (Weaver 2021), lessons from the history and foundations of physics reveal precisely how such resolution is achieved.

Most paradoxes of self-reference have a dual or ‘hypodox’. The Liar paradox (Lr = ‘Lr is false’) has the Truth-Teller (Tt = ‘Tt is true’). Russell’s paradox, which involves the set of sets that are not self-membered, has a dual involving the set of sets which are self-membered, etc. It is widely believed that these duals are not paradoxical or at least not as paradoxical as the paradoxes of which they are duals. In this paper, I argue that (...) some paradox’s duals or hypodoxes are as paradoxical as the paradoxes of which they are duals, and that they raise neglected and interestingly different problems. I first focus on Richard’s paradox (arguably the simplest case of a paradoxical dual), showing both that its dual is as paradoxical as Richard’s paradox itself, and that the classical, Richard-Poincaré solution to the latter does not generalize to the former in any obvious way. I then argue that my argument applies mutatis mutandis to other paradoxes of self-reference as well, the dual of the Liar (the Truth-Teller) proving paradoxical. (shrink)

This paper seeks to question the position of ZF as the dominant system of set theory, and in particular to examine whether there is any philosophical justification for the axiom of foundation. After some historical observations regarding Poincare and Russell, and the notions of circularity and hierarchy, the iterative conception of set is argued to be a semi-constructvist hybrid without philosophical coherence. ZF cannot be justified as necessary to avoid paradoxes, as axiomatizing a coherent notion of set, nor on pragmatic (...) grounds, and should be replaced by a system allowing non-well-founded sets. (shrink)

The key philosophic concepts - wholeness and duality - are analyzed on the basis of general scientific and vision ideas of H. Poincaré. His cellular structure with full set of topological invariants (cycles) can be considered as a model of dual arrangement of the World. The World is seen as a multidimensional process, consisting not of parts, but of local processes, adjoining each other. It is demonstrated, that a set of cycles at each structural level not only resolve paradoxes (...) of wholeness and development, but represents a recommencing process, which reproduces its own environment. The wholeness – world is considered as a duality of flows and potentials, which arrange and produce absolutely different structures, being closely conjugated, as cycles and co-cycles within the whole. Thestreams are structured and coordinated towards decrease of structural level dimensions: from the general to the particular, from the concrete to the abstract, from the depth to the surface. This is the direction of differentiation of the whole. Potentials are coordinated in the opposite direction, with increase of dimension, through structural elements of higher dimensions. The world is gathered, integrated, joined, specified through stresses; differentiated parts tend to scatter, connections between them strain and turn them back to their whole. A penetration of the scientist into more complicated processes turns out to be a movement within a closed multidimensional surface (closed manifold), enriched with new dimensions with inclusion of new processes. Those concrete examples illustrate importance of Poincaré duality theorem for closed manifolds. (shrink)

The key philosophic concepts - wholeness and duality - are analyzed on the basis of general scientific and vision ideas of H. Poincaré. His cellular structure with full set of topological invariants (cycles) can be considered as a model of dual arrangement of the World. The World is seen as a multidimensional process, consisting not of parts, but of local processes, adjoining each other. It is demonstrated, that a set of cycles at each structural level not only resolve paradoxes (...) of wholeness and development, but represents a recommencing process, which reproduces its own environment. The wholeness – world is considered as a duality of flows and potentials, which arrange and produce absolutely different structures, being closely conjugated, as cycles and co-cycles within the whole. Thestreams are structured and coordinated towards decrease of structural level dimensions: from the general to the particular, from the concrete to the abstract, from the depth to the surface. This is the direction of differentiation of the whole. Potentials are coordinated in the opposite direction, with increase of dimension, through structural elements of higher dimensions. The world is gathered, integrated, joined, specified through stresses; differentiated parts tend to scatter, connections between them strain and turn them back to their whole. A penetration of the scientist into more complicated processes turns out to be a movement within a closed multidimensional surface (closed manifold), enriched with new dimensions with inclusion of new processes. Those concrete examples illustrate importance of Poincaré duality theorem for closed manifolds. (shrink)

" Vivid . . . immense clarity . . . the product of a brilliant and extremely forceful intellect." — Journal of the Royal Naval Scientific Service "Still a sheer joy to read." — Mathematical Gazette "Should be read by any student, teacher or researcher in mathematics." — Mathematics Teacher The originator of algebraic topology and of the theory of analytic functions of several complex variables, Henri Poincare (1854–1912) excelled at explaining the complexities of scientific and mathematical ideas to lay (...) readers. Science and Method, written in 1908, has been appreciated by a wide audience of nonprofessionals and translated into many languages. It defines the basic methodology and psychology of scientific discovery, particularly in regard to mathematics and mathematical physics. Drawing on examples from many fields, it explains how scientists analyze and choose their working facts, and it explores the nature of experimentation, theory, and the mind. 1914 edition. Translated by Francis Maitland. (shrink)

The Principle of Indifference is a central element of the ‘classical’ conception of probability, but, for all its strong intuitive appeal, it is widely believed that it faces a devastating objection: the so-called (by Poincare´) ‘Bertrand paradoxes’ (in essence, cases in which the same probability question receives different answers). The puzzle has fascinated many since its discovery, and a series of clever solutions (followed promptly by equally clever rebuttals) have been proposed. However, despite the long-standing interest in this problem, an (...) important assumption, necessary for its generation, has been overlooked. My aim in this paper is to identify this assumption. Since what it claims turns out to be prima facie problematic, I will urge that the burden of proof now shifts to the objectors to PI; they have to provide reasons why this assumption holds. (shrink)

This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work. This work is in the public domain (...) in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant. (shrink)

Este texto introduz a tradução do discurso de intitulado "Sobre os números transfinitos" ("Über transfinite Zahlen"), proferido por Henri Poincaré em 27 de abril de 1909, na Universidade de Göttingen. Após uma breve apresentação do pensamento do autor acerca dos fundamentos da aritmética, procura-se citar os aspectos mais relevantes da chamada crise dos fundamentos da matemática, para então introduzir a reformulação do conceito de predicatividade aventada no referido discurso sobre números transfinitos, contribuição compreendida como um recurso teórico necessário para (...) a superação dos paradoxos relativos à teoria dos conjuntos. Com isso, pretende-se evidenciar o papel central do texto publicado nesta edição para o desenvolvimento da concepção matemática de Henri Poincaré. This article provides an introduction to the translation of the lecture entitled "On transfinite numbers" ("Über transfinite Zahlen"), given by Henri Poincaré at the University of Göttingen on April 27, 1909. Following a short presentation of Poincaré's views on the foundations of arithmetic, it identifies the aspects of the so-called crisis of the foundations of mathematics that are most relevant for understanding his reconstruction of the concept of predicativity, which is intended to be a theoretical resource that may overcome the paradoxes of set theory. In doing so, the article highlights the central role of this text in the process of maturation of Poincaré's views on the foundations of mathematics. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:January 22, 2009 (8:41 pm) G:\WPData\TYPE2802\russell 28,2 048red.wpd russell: the Journal of Bertrand Russell Studies n.s. 28 (winter 2008–09): 127–42 The Bertrand Russell Research Centre, McMaster U. issn 0036-01631; online 1913-8032 YABLO’S PARADOX AND RUSSELLIAN PROPOSITIONS Gregory Landini Philosophy / U. of Iowa Iowa City, ia 52242–1408, usa [email protected] Is self-reference necessary for the production of Liar paradoxes? Yablo has given an argument that self-reference is not necessary. (...) He hopes to show that the indexical apparatus of self-reference of the traditional Liar paradox can be avoided by appealing to a list, a consecutive sequence, of sentences correlated one-one withnaturalnumbers.Yabloopens his “Paradox without Self-Reference” (Analysis, 1993) with the assumption that there is a sequence such that: Snz: “(;k)(k > n.!. True Sk)” Each sentence on Yablo’s list is supposed to be correlated one-one with number n. Each sentence is supposed to say that for every natural number kz greater than n, the k-th sentence on the list is not true. By comparing Yablo’s construction to an analogous construction with early Russellian propositions, we show that Yablo has failed to generate a paradox. 1. vicious circularity in yablo’s paradox S elf-reference has been taken to be the source of paradoxes. Poincaré and Russell are commonly associated with this thesis. In an amusing passage, the mathematician Jourdain recalls something of the dialogue between them: Nearly all mathematicians agreed that the way to solve these paradoxes was simply not to mention them; but there was some divergence of opinion as to how they were to be unmentioned. It was clearly unsatisfactory merely not to mention them. Thus Poincaré was apparently of the opinion that the best way of avoiding such awkward subjects was to mention that they were not to be mentioned. But [as Russell put it] “one might as well, in talking to a man with January 22, 2009 (8:41 pm) G:\WPData\TYPE2802\russell 28,2 048red.wpd 128 gregory landini 1 Philip Jourdain, The Philosophy of Mr. B*rtr*nd R*ss*llz (London: Allen & Unwin, 1918), p. 77. Russell is quoted from “Mathematical Logic as Based on the Theory of Types” (1908), LK, p. 63. 2 “On ‘Insolubilia’ and Their Solution By Symbolic Logic”, in B. Russell, Essays in Analysis, ed. Douglas Lackey (London: Allen & Unwin, 1973), p. 196. 3 I believe that this is Russell’s view in 1906. See Gregory Landini, “Russell’s Separation of the Logical and Semantic Paradoxes”, Revue internationale de philosophie 58 (2004): 257–94 (issue titled “Russell en héritage / Le centenaire des Principes”, ed. Philippe de Rouilhan). a long nose, say: ‘When I speak of noses, I except such as are inordinately long’, which would not be a very successful eTort to avoid a painful topic.”1 Poincaré maintained that one should exclude the oTending cases and therebyavoid“viciouscircles”ofself-referencewhichgenerateparadoxes. Russell objected: We may illustrate this by what M. Poincaré says concerning Richard’s paradox. Having Wrst put E = “all numbers deWnable in a Wnite number of words” we arrive at a paradox, due, says M. Poincaré, to our having included a number only deWnable in a Wnite number of words by means of E. This vicious circle he proposes to avoid by deWning E as “all numbers deWnable in a Wnite number of words without mentioning Ey”. To the uninitiated, this deWnition looks more circular than ever.2 Russell held that some paradoxes such as those of classes require, in order to exclude oTending cases without mentioning them, a “reconstruction of logical Wrst principles”. Others, such as Richard’s, are to be dismissed because they involve confused and viciously circular notions of “deWnability ”.3 Is self-reference necessary for paradoxes? The question is not well crafted. There are quite diTerent notions ofz “self-reference” involved in paradoxes. The self-reference involved in the Liar “This sentence is false” is provided by an apparatus of indexicals. This apparatus is quite distinct from the self-reference involved in Russell’s early ontology of propositions (as mind- and language-independent states of aTairs). This is an ontological self... (shrink)

Le savant et la science -- Le raisonnement mathématique -- La mécanique nouvelle -- La science astronomique.

" Vivid . . . immense clarity . . . the product of a brilliant and extremely forceful intellect." — Journal of the Royal Naval Scientific Service "Still a sheer joy to read." — Mathematical Gazette "Should be read by any student, teacher or researcher in mathematics." — Mathematics Teacher The originator of algebraic topology and of the theory of analytic functions of several complex variables, Henri Poincare (1854–1912) excelled at explaining the complexities of scientific and mathematical ideas to lay (...) readers. Science and Method, written in 1908, has been appreciated by a wide audience of nonprofessionals and translated into many languages. It defines the basic methodology and psychology of scientific discovery, particularly in regard to mathematics and mathematical physics. Drawing on examples from many fields, it explains how scientists analyze and choose their working facts, and it explores the nature of experimentation, theory, and the mind. 1914 edition. Translated by Francis Maitland. (shrink)

THE VALUE OF SCIENCE INTRODUCTION The search for truth should be the goal of our activities; it is the sole end worthy of them. Doubtless we should first bend our efforts to assuage human suffering, but why ? Not to suffer is a negative ...

"Science et méthode" de Henri Poincaré. Mathématicien, physicien et philosophe français (1854-1912).

This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in (...) the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant. (shrink)

During his lifetime, Henri Poincaré published three major philosophical books which achieved great success: "La science et l'hypothèse" (1902), "La valeur de la science" (1905) and "Science et méthode" (1908). After his death in 1913, a fourth volume of his philosophical works was published by his heirs as "Dernières pensées" (1913). The four books constitute the core of Poincaré's philosophic works and were given an ovation by scientific and general public. Around 1919, Gustave Le Bon wrote to (...) class='Hi'>Poincaré's widow. As the director of the "Bibliothèque de Philosophie Scientifique at Flammarion", he asked her permission to publish a second posthumous volume. "L'Opportunisme scientifique" was intended to be the fifth and final volume of Poincaré's philosophical writings. Louis Rougier had elaborated the project, with the collaboration of Gustave Le Bon, and the approval of the philosopher Émile Boutroux and his son Pierre. Because of the reservations of the mathematician's heirs, this book was never published and Dernières pensées remained his last philosophical book. Nevertheless Poincaré's correspondence - which is kept in the Poincaré Archives at University Nancy 2 - contains a large amount of documents concerning the project, its justification and the discussions between Louis Rougier and the mathematician's heirs. The aim of this book is to restore this episode, which gives some crucial informations about editorial practices of Poincaré and about the posterity of his philosophic thinking. (shrink)

"Dernières pensées" de Henri Poincaré. Mathématicien, physicien et philosophe français (1854-1912).

"La Valeur de la Science" de Henri Poincaré. Mathématicien, physicien et philosophe français (1854-1912).

On the nature of mathematical reasoning -- Mathematical magnitude and experience -- Non-Euclidian geometries -- Space and geometry -- Experience and geometry -- Classical mechanics -- Relative and absolute motion -- Energy and thermodynamics -- Hypotheses in physics -- Theories of modern physics -- Probability calculus -- Optics and electricity -- Electrodynamics -- The end of matter.

Here is an accurate and readable translation of a seminal article by Henri Poincaré that is a classic in the study of dynamical systems popularly called chaos theory. In an effort to understand the stability of orbits in the solar system, Poincaré applied a Hamiltonian formulation to the equations of planetary motion and studied these differential equations in the limited case of three bodies to arrive at properties of the equations' solutions, such as orbital resonances and horseshoe orbits. Poincaré wrote (...) for professional mathematicians and astronomers interested in celestial mechanics and differential equations. Contemporary historians of math or science and researchers in dynamical systems and planetary motion with an interest in the origin or history of their field will find his work fascinating. (shrink)