Este artigo examina a sociedade utópica esboçada na Nova Atlântida de Francis Bacon. As interpretações modernas costumam afirmar que ela é, de modo geral, caracterizada por influências cristãs. Essa compreensão é questionada e uma interpretação alternativa é discutida. Bacon emprega um sistema complexo de indicações veladas, símbolos e alusões com "ambigiidades. Isso sugere que não há um único pano de fundo filosófico, religioso ou cultural para sua sociedade utópica. Portanto, eu sustento que a identidade social da Nova (...) Atlântida é baseada num sincretismo intercultural. (shrink)

Pela pena de homens de letras de Portugal e do Brasil, a aproximação cultural entre os dois países tornou-se um ideal pelo qual valia a pena lutar e que encontrou espaço adequado nas recentes sociedades republicanas de aquém e além-Atlântico. João de Barros e Olavo Bilac foram os arautos deste projecto que, exaltando os laços de uma comum identidade – história, tradição, cultura, raça – e neles se fundamentando, salvaguardadas as respectivas independências, pretendia criar, em conjunto com Angola, uma unidade (...) política de domínio do Atlântico Sul e de interlocutora forte na cena internacional. Neste sentido, deram corpo a uma verdadeira militância que iria encontrar na criação da revista Atlântida, patrocinada por altas entidades da política externa dos dois governos, a sua expressão de maior significado. (shrink)

This comprehensive account of the concept and practices of deduction is the first to bring together perspectives from philosophy, history, psychology and cognitive science, and mathematical practice. Catarina Dutilh Novaes draws on all of these perspectives to argue for an overarching conceptualization of deduction as a dialogical practice: deduction has dialogical roots, and these dialogical roots are still largely present both in theories and in practices of deduction. Dutilh Novaes' account also highlights the deeply human and in fact social nature (...) of deduction, as embedded in actual human practices; as such, it presents a highly innovative account of deduction. The book will be of interest to a wide range of readers, from advanced students to senior scholars, and from philosophers to mathematicians and cognitive scientists. (shrink)

Two periods in the history of logic and philosophy are characterized notably by vivid interest in self-referential paradoxical sentences in general, and Liar sentences in particular: the later medieval period (roughly from the 12th to the 15th century) and the last 100 years. In this paper, I undertake a comparative taxonomy of these two traditions. I outline and discuss eight main approaches to Liar sentences in the medieval tradition, and compare them to the most influential modern approaches to such sentences. (...) I also emphasize the aspects of each tradition that find no counterpart in the other one. It is expected that such a comparison may point in new directions for future research on the paradoxes; indeed, the present analysis allows me to draw a few conclusions about the general nature of Liar sentences, and to identify aspects that would require further investigation. (shrink)

A distinction often drawn is one between conservative versus revisionary conceptions of philosophical analysis with respect to commonsensical beliefs and intuitions. This paper offers a comparative investigation of two revisionary methods: Carnapian explication and ameliorative analysis as developed by S. Haslanger. It is argued that they have a number of common features, and in particular that they share a crucial political dimension: they both have the potential to serve as instrument for social reform. Indeed, they may produce improved versions of (...) key concepts of everyday life, for example those pertaining to social categories such as gender and race, which in turn may lead to social change. The systematic comparison of these two frameworks offered here, where similarities as well as differences are discussed, is likely to provide useful guidance to practitioners of both approaches, as it will highlight important aspects of each of them that tend to remain implicit and under-theorized in existing applications of these methodologies to specific questions. (shrink)

Formal languages are widely regarded as being above all mathematical objects and as producing a greater level of precision and technical complexity in logical investigations because of this. Yet defining formal languages exclusively in this way offers only a partial and limited explanation of the impact which their use actually has. In this book, Catarina Dutilh Novaes adopts a much wider conception of formal languages so as to investigate more broadly what exactly is going on when theorists put these tools (...) to use. She looks at the history and philosophy of formal languages and focuses on the cognitive impact of formal languages on human reasoning, drawing on their historical development, psychology, cognitive science and philosophy. Her wide-ranging study will be valuable for both students and researchers in philosophy, logic, psychology and cognitive and computer science. (shrink)

I examine the theory of consequentia of the medieval logician, John Buridan. Buridan advocates a strict commitment to what we now call proposition-tokens as the bearers of truth-value. The analysis of Buridan's theory shows that, within a token-based semantics, amendments to the usual notions of inference and consequence are made necessary, since pragmatic elements disrupt the semantic behaviour of propositions. In my reconstruction of Buridan's theory, I use some of the apparatus of modern two-dimensional semantics, such as two-dimensional matrices and (...) the distinction between the context of formation and the context of evaluation of utterances. (shrink)

The paper argues that much of the difficulty with making progress on the issue of the normativity of logic for thought, as discussed in the literature, stems from a misapprehension of what logic is normative for. The claim is that, rather than mono-agent mental processes, logic in fact comprises norms for quite specific situations of multi-agent dialogical interactions, in particular special forms of debates. This reconceptualization is inspired by historical developments in logic and mathematics, in particular the pervasiveness of such (...) dialogical conceptions in the early days of logic in ancient Greece. The multi-agent, dialogical perspective then allows for the formulation of compelling 'bridge principles’ between the relation of logical consequence and dialogical normative principles, something that is notoriously difficult to achieve in a mono-agent setting pertaining exclusively to thought and belief. The upshot is also that the truth-preserving rules of logic generally do not have a primary normative bearing on mono-agent mental processes, and in this sense the paper sides with Harman's critique of the idea that logic has a normative import for thought and belief. (shrink)

This book presents novel formalizations of three of the most important medieval logical theories: supposition, consequence and obligations. In an additional fourth part, an in-depth analysis of the concept of formalization is presented - a crucial concept in the current logical panorama, which as such receives surprisingly little attention.Although formalizations of medieval logical theories have been proposed earlier in the literature, the formalizations presented here are all based on innovative vantage points: supposition theories as algorithmic hermeneutics, theories of consequence analyzed (...) with tools borrowed from model-theory and two-dimensional semantics, and obligations as logical games. For this reason, this is perhaps the first time that these medieval logical theories are made fully accessible to the modern philosopher and logician who wishes to obtain a better grasp of them, but who has always been held back by the lack of appropriate ‘translations' into modern terms.Moreover, the book offers a reflection on the very nature of logic, a reflection that is prompted by the comparisons between medieval and modern logic, their similarities and dissimilarities. It is thus a contribution not only to the history of logic, but also to the philosophy of logic, the philosophy of language and semantics.The analysis of medieval logic is also relevant for the modern philosopher and logician in that, being the unifying methodology used across all disciplines at that time, logic really provided unity to science. It thus presents a unified model of scientific investigation, where logic plays the aggregating role. (shrink)

What does it mean to say that logic is formal? The short answer is: it means (or can mean) several different things. In this paper, I argue that there are (at least) eight main variations of the notion of the formal that are relevant for current discussions in philosophy and logic, and that they are structured in two main clusters, namely the formal as pertaining to forms, and the formal as pertaining to rules. To the first cluster belong the formal (...) as schematic; the formal as indifference to particulars; the formal as topic-neutrality; the formal as abstraction from intentional content; the formal as de-semantification. To the second cluster belong the formal as computable; the formal as pertaining to regulative rules; the formal as pertaining to constitutive rules. I analyze each of these eight variations, providing their historical background and raising related philosophical questions. The significance of this work of ?conceptual archeology? is that it may enhance clarity in debates where the notion of the formal plays a prominent role (such as debates where it is expected to play a demarcating role), but where it is oftentimes used equivocally and/or imprecisely. (shrink)

Explication is the conceptual cornerstone of Carnap’s approach to the methodology of scientific analysis. From a philosophical point of view, it gives rise to a number of questions that need to be addressed, but which do not seem to have been fully addressed by Carnap himself. This paper reconsiders Carnapian explication by comparing it to a different approach: the ‘formalisms as cognitive tools’ conception. The comparison allows us to discuss a number of aspects of the Carnapian methodology, as well as (...) issues pertaining to formalization in general. We start by introducing Carnap’s conception of explication, arguing that there is a tension between his proposed criteria of fruitfulness and similarity; we also argue that his further desideratum of exactness is less crucial than might appear at first. We then bring in the general idea of formalisms as cognitive tools, mainly by discussing the reliability of so-called statistical prediction rules, i.e. simple algorithms used to make predictions across a range of areas. SPRs allow for a concrete instantiation of Carnap’s fruitfulness desideratum, which is arguably the most important desideratum for him. Finally, we elaborate on what we call the ‘paradox of adequate formalization’, which for the Carnapian corresponds to the tension between similarity and fruitfulness. We conclude by noting that formalization is an inherently paradoxical enterprise in general, but one worth engaging in given the ‘cognitive boost’ it affords as a tool for discovery. (shrink)

Argumentation is important for sharing knowledge and information. Given that the receiver of an argument purportedly engages first and foremost with its content, one might expect trust to play a negligible epistemic role, as opposed to its crucial role in testimony. I argue on the contrary that trust plays a fundamental role in argumentative engagement. I present a realistic social epistemological account of argumentation inspired by social exchange theory. Here, argumentation is a form of epistemic exchange. I illustrate my argument (...) with two real-life examples: vaccination hesitancy, and the undermining of the credibility of traditional sources of information by authoritarian politicians. (shrink)

The thought of François Jullien has made valuable contributions to contemporary philosophy, primarily by enriching the interpretation of certain classic themes through the uniqueness of ancient Chinese wisdom. This approach has revealed aspects that Western philosophy, with its metaphysics focused on being, has overlooked. Among these aspects, Jullien has drawn attention to how a series of resources of what could be called ‘Christian thought’ have remained unthought-of, at least from a philosophical perspective. The central question of this research is whether (...) this Christian logic represents just another resource, among several, that Jullien has utilized in his intellectual work, or if it also constitutes one of the fundamental sources of his own work and the beginnings of possible de-coincidence from the philosophy of being. The conclusions indicate a notable and indispensable presence of these Christian notions in his argumentative proposal, albeit without resorting to faith. This study will begin by reviewing the main theses of the French philosopher and, at the same time, will describe how he has been relating and discussing them with Christian doctrine. (shrink)

Kaum ein Buch hat so viele und so kontroverse Reaktionen verursacht wie Simone de Beauvoirs "Das Andere Geschlecht". Der Sammelband gibt einen Einblick in die aktuelle internationale Beauvoir-Debatte und die Art und Weise wie das fünfzigjährige Jubiläum des "Anderen Geschlechts" gefeiert wurde. Die Autorinnen versuchen die verschiedenen Grundthemen von Beauvoirs Werk, wie Geschlecht und Körper (D. Lamoureux, M. Couillard, M. L. Femenías), Gleichheit und Differenz (S. Kruks, Y. Raynova, S. Bainbrigge), Ausschluss und Anerkennung (D. Bergoffen, S. Moser), Verantwortung und Engagement (...) (F. Rétif, N. Bauer, K. Arp, Dauphin, C. Gater), aus der Perspektive der Gegenwart neu zu beleuchten. Darüber hinaus enthält der Band biographische (K. Vintges, B. Weisshaupt) und bibliographische Beiträge, die ihn zu einem Nachschlagewerk und zu einer Dokumentation der gegenwärtigen Beauvoirforschung werden lassen. Aus dem Inhalt: Françoise Rétif: Zur Aktualität von Simone de Beauvoir oder die Dialektik des Engagements - Nancy Bauer: First Philosophy, "The Second Sex", and the Third Wave - Debra Bergoffen: Simone de Beauvoir and Jean-Paul Sartre: Woman, Man and the Desire to be God - Elaine Stavro-Pearce: Transgressing Sartre: embodied situated subjects in "The Second Sex" - Susanne Moser: Subjekt und Anerkennung: Zum Problem des Ausschlusses von Frauen und Weiblichkeit im" Anderen Geschlecht" - Diane Lamoureux: Der Paradox des Körpers bei Simone de Beauvoir - Marie Couillard: Die Lesbierin bei Simone de Beauvoir und Nicole Brossard - María Luisa Femenías: Beauvoir revisited: Butler and the "gender" question - Sonia Kruks: Panopticism and Shame: Reading Foucault through Beauvoir - Yvanka B. Raynova: Für eine postmoderne Ethik der Gerechtigkeit: Simone de Beauvoir und Jean-François Lyotard - Kristana Arp: Moral obligation in Simone de Beauvoir's "The Ethics of Ambiguity" - Susan Bainbrigge: The Impact of Simone de Beauvoir's "universel singularisé" on the Politics of Representation and the Representation of Politics - Sandrine Dauphin: From Socialism to radical Feminism: Militant foundations in Simone de Beauvoir's Writings - Claudia Gather: Simone de Beauvoir, eine Klassikerin der feministischen Soziologie? - Karen Vintges: Beauvoir's autobiography: "autofiction" or selftechnique? - Brigitte Weisshaupt: Simone de Beauvoir und Jean-Paul Sartre. Eine Anmerkung - Susanne Moser/Yvanka B. Raynova: "50 Jahre 'Das andere Geschlecht'": Zur internationalen Konferenz in Paris (19.-23.01.1999). (shrink)

Genealogical anxiety is the worry that the origins of beliefs, once revealed to be influenced by “irrelevant” factors such as personal histories and circumstances of upbringing, will undermine or cast doubt on those beliefs. Discussions on these irrelevant influences in the epistemological literature have so far primarily focused on their contingency. But there is another issue that merits further examination: the fact that epistemic environments condition beliefs suggests that epistemic agency is significantly curtailed. I present a model of belief-forming processes (...) that highlights how networks of attention and trust/distrust influence these processes. The model suggests that, while there is a lot happening beyond our control that shapes what we come to believe, we still retain some degree of agency to the extent that we can rewire our networks of attention and trust/distrust. I conclude that, surprisingly, genealogical anxiety may in fact increase agency insofar as it may encourage critical resistance. (shrink)

The paper investigates the propriety of applying the form versus matter distinction to arguments and to logic in general. Its main point is that many of the currently pervasive views on form and matter with respect to logic rest on several substantive and even contentious assumptions which are nevertheless uncritically accepted. Indeed, many of the issues raised by the application of this distinction to arguments seem to be related to a questionable combination of different presuppositions and expectations; this holds in (...) particular of the vexed issue of demarcating the class of logical constants. I begin with a characterization of currently widespread views on form and matter in logic, which I refer to as 'logical hylomorphism as we know it'—LHAWKI, for short—and argue that the hylomorphism underlying LHAWKI is mereological. Next, I sketch an overview of the historical developments leading from Aristotelian, non-mereological metaphysical hylomorphism to mereological logical hylomorphism (LHAWKI). I conclude with a reassessment of the prospects for the combination of hylomorphism and logic, arguing in particular that LHAWKI is not the only and certainly not the most suitable version of logical hylomorphism. In particular, this implies that the project of demarcating the class of logical constants as a means to define the scope and nature of logic rests on highly problematic assumptions. (shrink)

It is well known that reductio ad absurdum arguments raise a number of interesting philosophical questions. What does it mean to assert something with the precise goal of then showing it to be false, i.e. because it leads to absurd conclusions? What kind of absurdity do we obtain? Moreover, in the mathematics education literature number of studies have shown that students find it difficult to truly comprehend the idea of reductio proofs, which indicates the cognitive complexity of these constructions. In (...) this paper, I start by discussing four philosophical issues pertaining to reductio arguments. I then briefly present a dialogical conceptualization of deductive arguments, according to which such arguments are best understood as a dialogue between two participants—Prover and Skeptic. Finally, I argue that many of the philosophical and cognitive difficulties surrounding reductio arguments are dispelled or at least further clarified once one adopts a dialogical perspective. (shrink)

Since at least the 1980s, the role of adversariality in argumentation has been extensively discussed within different domains. Prima facie, there seem to be two extreme positions on this issue: argumentation should never be adversarial, as we should always aim for cooperative argumentative engagement; argumentation should be and in fact is always adversarial, given that adversariality is an intrinsic property of argumentation. I here defend the view that specific instances of argumentation are adversarial or cooperative to different degrees. What determines (...) whether an argumentative situation should be primarily adversarial or primarily cooperative are contextual features and background conditions external to the argumentative situation itself, in particular the extent to which the parties involved have prior conflicting or else convergent interests. To further develop this claim, I consider three teloi that are frequently associated with argumentation: the epistemic telos, the consensus-building telos, and the conflict management telos. I start with a brief discussion of the concepts of adversariality, cooperation, and conflict in general. I then sketch the main lines of the debates in the recent literature on adversariality in argumentation. Next, I discuss the three teloi of argumentation listed above in turn, emphasizing the roles of adversariality and cooperation for each of them. (shrink)

In The Enigma of Reason, Mercier and Sperber (M&S) present and defend their interactionist account of reason. In this piece, I discuss briefly the points of agreement between M&S and myself and, more extensively, the points of disagreement, most of which pertain to details of the evolutionary components of their account. I discuss in particular the purported modular nature of reason; their account of myside bias as an optimum/adaptation; and the claim that reason thus construed must be an individual‐level and (...) not a group‐level adaptation. In the final section, I offer brief considerations on an alternative account of reasoning, where the focus is on how sociocultural environments may tune the social production and evaluation of arguments. (shrink)

This volume, the first dedicated and comprehensive companion to medieval logic, covers both the Latin and the Arabic traditions, and shows that they were in fact sister traditions, which both arose against the background of a Hellenistic heritage and which influenced one another over the centuries. A series of chapters by both established and younger scholars covers the whole period including early and late developments, and offers new insights into this extremely rich period in the history of logic. The volume (...) is divided into two parts, 'Periods and Traditions' and 'Themes', allowing readers to engage with the subject from both historical and more systematic perspectives. It will be a must-read for students and scholars of medieval philosophy, the history of logic, and the history of ideas. (shrink)

I argue that the medieval form of dialectical disputation known as obligationes can be viewed as a logical game of consistency maintenance. The game has two participants, Opponent and Respondent. Opponent puts forward a proposition P; Respondent must concede, deny or doubt, on the basis of inferential relations between P and previously accepted or denied propositions, or, in case there is none, on the basis of the common set of beliefs. Respondent loses the game if he concedes a contradictory set (...) of propositions. Opponent loses the game if Respondent is able to maintain consistency during the stipulated period of time. The obligational rules are here formalised by means of familiar notational devices, and the application of some game-theoretical concepts, such as (winning) strategy, moves, motivation, allows for an analysis of some crucial properties of the game. In particular, the primacy of inferential (syntactic) relations over semantic aspects and the dynamic character of obligations are outlined. (shrink)

El propósito del presente escrito es hacer un análisis de algunas defensas universalistas sobre el segundo argumento de Z13 el cual niega que el universal pueda ser forma y, de esta manera, que pueda ser substancia primera. El análisis tiene dos momentos: en el primero se sostiene que, basado en la evidencia textual de Z, hay una premisa falsa y esto conduce a que la estructura general de uno de los principales argumentos universalistas sea inconsistente. El segundo momento del análisis (...) consiste en mostrar una serie de distinciones importantes no trazadas del segundo argumento que conducen, nuevamente, a que el argumento universalista no sea consistente. (shrink)

In describing numerosity as “a kind of ersatz number,” Clarke and Beck fail to consider a familiar and compelling definition of numerosity, which conceptualizes numerosity as the cognitive counterpart of the mathematical concept of cardinality; numerosity is the magnitude, whereas number is a scale through which numerosity/cardinality is measured. We argue that these distinctions should be considered.

Overdoing Democracy is an important contribution to the literature on (deliberative) democracy, as it offers a sobering diagnosis of the risks and pitfalls of (overdoing) democracy in the form of internal critique. But the book does not go far enough in its diagnosis because it is not sufficiently critical towards some of the basic assumptions of deliberative conceptions of democracy. In particular, Talisse does not sufficiently attend to the inevitable power struggles in a society, where different groups and individuals must (...) protect their own (often conflicting) interests instead of working towards a ‘common good.’ In this essay, I contrast two different visions of democracy and politics, one based on ideals of consensus and cooperation, and another on the inevitability of perennial conflict. I then briefly present an alternative to deliberative conceptions of democracy that has gained traction in recent decades, known as agonism. Next, I offer a short reconstruction of Talisse’s proposal, and finally I sketch a critical assessment of some of his main claims and assumptions from an agonistic perspective. (shrink)

Can arguments change minds? Philosophers like to think that they can. However, a wealth of empirical evidence suggests that arguments are not very efficient tools to change minds. What to make of the different assessments of the mind-changing potential of arguments? To address this issue, we must take into account the broader contexts in which arguments occur, in particular the propagation of messages across networks of attention, and the choices that epistemic agents must make between alternative potential sources of content (...) and information, which are very much influenced by perceptions of reliability and trustworthiness. Arguments can change minds, but only under conducive, favourable socio-epistemic conditions. (shrink)

In the scholarship on medieval logic and semantics of the last decades, Ockham’s theory of supposition is probably the most extensively studied version of such theories; yet, it seems that we still do not fully understand all its intricacies. In this paper, I focus on a phrase that occurs countless times throughout Ockham’s writings, but in particular in the sections dedicated to supposition in the Summa logicae: the phrase ‘denotatur’. I claim that an adequate understanding of the role of the (...) concept of denotatur within Ockham’s supposition theory shall yield a deeper understanding of the theory as a whole. Here, I first examine a few uses of the term ‘denotatur’ and its variants by other authors. I then turn to Ockham: first I briefly mention some uses of the term in contexts other than his theory of supposition. Following that, I focus on his supposition theory, in particular on how ‘denotatur’ allows him to deal with two crucial puzzles, namely the supposition of empty terms and the supposition of terms in false affirmative propositions. The treatment of these two puzzles suggests that Ockham’s theory of supposition must be understood as a theory chiefly intended for the generation of the meanings of propositions. (shrink)

In Bad Beliefs, Levy presents a picture of belief-forming processes according to which, on most matters of significance, we defer to reliable sources by relying extensively on cultural and social cues. Levy conceptualizes the kind of evidence provided by socio-cultural environments as higher-order evidence. But his notion of higher-order evidence seems to differ from those available in the epistemological literature on higher-order evidence, and this calls for a reflection on how exactly social and cultural cues are/count as/provide higher-order evidence. In (...) this paper, I draw on the three-tiered model of epistemic exchange that I have been developing recently, which highlights the centrality of relations of attention and trust in belief-forming processes, to explicate how social and cultural cues provide higher-order evidence. I also argue that Levy’s account fails to sufficiently address the issue of strategic actors who have incentives to pollute epistemic environments for their benefit, and more generally the power struggles, incentives, and competing interests that characterize human sociality. Levy’s attempted reduction of the political to the epistemic ultimately fails, but his account of social and cultural cues as higher-order evidence offers an insightful perspective on epistemic social structures. (shrink)

We investigate the philosophical significance of the existence of different semantic systems with respect to which a given deductive system is sound and complete. Our case study will be Corcoran's deductive system D for Aristotelian syllogistic and some of the different semantic systems for syllogistic that have been proposed in the literature. We shall prove that they are not equivalent, in spite of D being sound and complete with respect to each of them. Beyond the specific case of syllogistic, the (...) goal is to offer a general discussion of the relations between informal notions—in this case, an informal notion of deductive validity—and logical apparatuses such as deductive systems and (model-theoretic or other) semantic systems that aim at offering technical, formal accounts of informal notions. Specifically, we will be interested in Kreisel's famous 'squeezing argument'; we shall ask ourselves what a plurality of semantic systems (understood as classes of mathematical structures) may entail for the cogency of specific applications of the squeezing argument. More generally, the analysis brings to the fore the need for criteria of adequacy for semantic systems based on mathematical structures. Without such criteria, the idea that the gap between informal and technical accounts of validity can be bridged is put under pressure. (shrink)

Thomas Bradwardine makes much of the fact that his solution to the insolubles is in accordance with Aristotle's diagnosis of the fallacy in the Liar paradox as that of secundum quid et simpliciter. Paul Spade, however, claims that this invocation of Aristotle by Bradwardine is purely "honorary" in order to confer specious respectability on his analysis and give it a spurious weight of authority. Our answer to Spade follows Bradwardine's response to the problem of revenge: any proposition saying of itself (...) that it is false says more than does Bradwardine's proposition saying of it that it is false, and so follows from that other proposition only in respect of part of what it says, and not simpliciter. (shrink)

Au cours des dernières décennies, les travaux portant sur les pratiques humaines réelles ont pris de l'importance dans différents domaines de la philosophie, sans pour autant atteindre une position dominante. À ce jour, ce type de tournant pratique n'a cependant pas encore pénétré la philosophie de la logique. En première partie, j'esquisse ce que serait (ou pourrait être) une philosophie de la logique centrée sur l'étude des pratiques, en insistant en particulier sur sa pertinence et sur la manière de la (...) conduire. En deuxième partie, j'illustre cette approche centrée sur les pratiques au moyen d une étude de cas : le rôle joué par les langages formels en logique, en particulier dans les pratiques des logiciens. Ma thèse est que les langages formels jouent un rôle opératoire fondamental dans le travail des logiciens en tant que technologie pratique du crayon et du papier, génératrice de processus cognitifs - et qui plus spécifiquement vient contrebalancer certains de nos schémas cognitifs « spontanés » peu adéquats à la recherche en logique (ainsi que dans d'autres domaines). Cette thèse sera appuyée sur des données empiriques venant de la recherche en psychologie du raisonnement. Avec cette analyse j'espère montrer qu'une philosophie de la logique centrée sur l'étude des pratiques peut être fructueuse, en particulier si elle est complétée par les réflexions méthodologiques nécessaires. (shrink)

In recent years, substructural approaches to paradoxes have become quite popular. But whatever restrictions on structural rules we may want to enforce, it is highly desirable that such restrictions be accompanied by independent philosophical motivation, not directly related to paradoxes. Indeed, while these recent developments have shed new light on a number of issues pertaining to paradoxes, it seems that we now have even more open questions than before, in particular two very pressing ones: what (independent) motivations do we have (...) (if any) for restrictions on structural rules, and what to make of the plurality of new logics emerging from these restrictions, i.e. how to ‘choose’ among the different options. In this paper, we address these two questions from the perspective of a dialogical conception of logic that we've been advocating in recent years. We will argue that dialogical interpretations of structural rules, that is, as rules determining specific properties of the dialogues in question, provide a conveniently neutral framework to adjudicate between the different substructural proposals that have been made in the literature on paradoxes. (shrink)

It is often remarked that first-order Peano Arithmetic is non-categorical but deductively well-behaved, while second-order Peano Arithmetic is categorical but deductively ill-behaved. This suggests that, when it comes to axiomatizations of mathematical theories, expressive power and deductive power may be orthogonal, mutually exclusive desiderata. In this paper, I turn to Hintikka’s :69–90, 1989) distinction between descriptive and deductive approaches in the foundations of mathematics to discuss the implications of this observation for the first-order logic versus second-order logic divide. The descriptive (...) approach is illustrated by Dedekind’s ‘discovery’ of the need for second-order concepts to ensure categoricity in his axiomatization of arithmetic; the deductive approach is illustrated by Frege’s Begriffsschrift project. I argue that, rather than suggesting that any use of logic in the foundations of mathematics is doomed to failure given the impossibility of combining the descriptive approach with the deductive approach, what this apparent predicament in fact indicates is that the first-order versus second-order divide may be too crude to investigate what an adequate axiomatization of arithmetic should look like. I also conclude that, insofar as there are different, equally legitimate projects one may engage in when working on the foundations of mathematics, there is no such thing as the One True Logic for this purpose; different logical systems may be adequate for different projects. (shrink)