Logic and psychology overlap in judgment, inference and proof. The problems raised by this commonality are notoriously difficult, both from a historical and from a philosophical point of view. Sundholm has for a long time addressed these issues. His beautiful piece of work [A Century of Inference: 1837-1936] begins by summarizing the main difficulty in the usual provocative manner of the author: one can start, he says, by the act of knowledge to go to the object, as the Idealist does; (...) one can also start by the object to go to the act, in the Realist mood; never the two shall meet. He is himself inclined to accept the first perspective as the right one and he has eventually developed an original version of antirealism which starts, not from considerations about the publicity of meaning, in the manner of Dummett, but from an epistemic standpoint, trying to search in a non-Fregean tradition of analysis of judgement and cognate notions a way of founding constructivist semantics. The present paper ploughes the same field. We concentrate on the significance, for Sundholm’s program, of the perspective that has been opened by Twardowski in his important essay on acts and products (1912. (shrink)

With a clear presentation, Ethics: Theory and Practice educates readers about ethical theory and has them apply what they learn to specific classic and contemporary moral problems (lying, cheating, establishing ethical business practices, honoring ethical obligations in medicine, etc.). Jacques P. Thiroux first wrote this text 1977 in order to educate readers about ethical theory and its applications in a way that beginning students could understand. The result was an accessible text that isn't too technical and doesn't plunge into (...) complex readings without sufficient background. The text is fully updated with global issues and non-Western ethical views. Keith W. Krasemann now continues Thiroux's efforts of making Ethical Ideas accesible to students. Besides updating the foundations of the text, Krasemann incoporates new and relevant material, most of which is often unique only to this text. (shrink)

The paper deals with the contributions of Jacques Herbrand to logic and philosophy in historical context.

The paper is a defense of a strict form of anti-realism, competing the "in principle" form defended by Michael Dummett. It proposes to ground anti-realism on the basis of two principles ("immanence" and "implicitness") and to develop the consequences of these principles in the light of sub-structural logics.

In recent decades we witnessed ongoing debates about the objectives of history education, with different underlying epistemological perspectives. This qualitative study explored prospective history teachers' beliefs about these objectives of history education. Prospective history teachers of six universities starting a teacher educational programme were invited to answer an open-ended questionnaire about history education. Six objectives were found: (1) memorising; (2) critical/explanatory; (3) constructivist; (4) perspective-taking; (5) moral; and (6) collective-identity objectives. Almost all prospective teachers mentioned several of these objectives. A (...) distinction between two epistemological perspectives on historical knowledge representation (factual or interpretive), was used as a framework for categorising the different objectives. More than half of the respondents mentioned objectives of history education that represent history as factual and objectives that represent history as interpretive. We propose that in actual practice most history teachers are combining epistemologically opposing objectives for pedagogical, political and religious motives. (shrink)

Standard epistemic logic actually formalizes folk-psychology. The problem of logical omniscience shows that this logic is not adequate in a cognitivist setting. In order to describe realistic information-processing believers, we need both an ontology of particulars and a hyper-intensional taxonomy of representations. From this point of view, sub-structural logics, which do not overlook the syntaxic details of the processing of information, are an interesting alternative to possible worlds semantics.

According to the realist, the meaning of a declarative, non-indexical sentence is the condition under which it is true and the truth-condition of an undecidable sentence can obtain or fail to obtain independently of our capacity, even in principle, to recognize that it obtains or that fails to do so.1 In a series of papers, beginning with “Truth” in 1959, Michael Dummett challenged the position that the classical notion of truth-condition occupied as the central notion of a theory of meaning, (...) and proposed that it should be replaced by the anti-realist (and intuitionistic) notion of assertability-condition. Taken together with normalization results obtained by Dag Prawitz, Dummett’s work truly opened up the anti-realist challenge at the level of proof-theoretical semantics.2 There has been since numerous rejoinders from partisans of classical logic, which were at times met with by attempts at watering down the anti-realist challenge, e.g., by arguing that anti-realism does not necessarily entail the adoption of intuitionistic logic. Only a few anti-realists, such as Crispin Wright and Neil Tennant, tried to look instead in the other direction, towards a more radical version of anti-realism which would entail deeper revisions of classical logic than those recommended by intuitionists.3 In this paper, which is largely programmatic, we shall also argue in favour of a radical anti-realism which would be a genuine alternative to the traditional anti-realism of Dummett and Prawitz. The debate about anti-realism has by now more or less run out of breath and we wish to provide it with a new lease on life, by taking into account the profound changes that took place in proof theory during the intervening years. We have in mind in particular the considerable development within Gentzen-style proof theory of non-classical, substructural logics other than intuitionistic logic, which seriously opens up the possibility that anti-realism, when properly understood, might end up justifying another logic, and the development of closer links between proof theory and computational complexity theory that has renewed interest in a radical form of anti-realism, namely strict finitism. (shrink)

Bolzano was the first to establish an explicit distinction between the deductive methods that allow us to recognise the certainty of a given truth and those that provide its objective ground. His conception of the relation between what we, in this paper, call "subjective consequence", i.e., the relation from epistemic reason to consequence and "objective consequence", i.e., grounding however allows for an interpretation according to which Bolzano advocates an "explicativist" conception of proof: proofs par excellence are those that reflect the (...) objective order of grounding. In this paper, we expose the problems involved by such a conception and argue in favour of a more rigorous demarcation between the ontological and the epistemological concern in the elaboration of a theory of demonstration. (shrink)

This paper can be read as an attempt at providing philosophical foundations to linear logic. The only plausible form of philosophical antirealism deals with practical feasibility rather than with effectivity in principle. The very notion of recognizability is ambiguous, audit has to be considered from a stricter perspective than currently done. The intuitionistic assertability conditions are to be reinforced. This change requires a move towards a frame in which the circumstances of the application of a logical rule can be specified. (...) Gentzen's sequential calculi provide such a frame, when some structural rules have been removed or limited. (shrink)

Ranging from Alan Turing’s seminal 1936 paper to the latest work on Kolmogorov complexity and linear logic, this comprehensive new work clarifies the relationship between computability on the one hand and constructivity on the other. The authors argue that even though constructivists have largely shed Brouwer’s solipsistic attitude to logic, there remain points of disagreement to this day. Focusing on the growing pains computability experienced as it was forced to address the demands of rapidly expanding applications, the content maps the (...) developments following Turing’s ground-breaking linkage of computation and the machine, the resulting birth of complexity theory, the innovations of Kolmogorov complexity and resolving the dissonances between proof theoretical semantics and canonical proof feasibility. Finally, it explores one of the most fundamental questions concerning the interface between constructivity and computability: whether the theory of recursive functions is needed for a rigorous development of constructive mathematics. This volume contributes to the unity of science by overcoming disunities rather than offering an overarching framework. It posits that computability’s adoption of a classical, ontological point of view kept these imperatives separated. In studying the relationship between the two, it is a vital step forward in overcoming the disagreements and misunderstandings which stand in the way of a unifying view of logic. (shrink)

Philosophy of Probability provides a comprehensive introduction to theoretical issues that occupy a central position in disciplines ranging from philosophy of ...

According to foundationalism, mathematical propositions form a complex objective structure we have to discover and in which each proposition depends for its truth on the propositions that precede and ground it. Proofs that only establish the truth of their conclusions are contrasted with proofs that give also the objective reason of that truth. Foundationalism claims that the cognitive resources required by these proofs are universally available. This paper tries to undermine that claim and to show that foundationalism is a dead (...) end. (shrink)

Bolzano fut le premier philosophe à établir une distinction explicite entre les procédés déductifs qui nous permettent de parvenir à la certitude d’une vérité et ceux qui fournissent son fondement objectif. La conception que Bolzano se fait du rapport entre ce que nous appelons ici, d’une part, « conséquence subjective », à savoir la relation de raison à conséquence épistémique et, d’autre part, la « conséquence objective », c’est-à-dire la fondation , suggère toutefois que Bolzano défendait une conception « explicativiste (...) » de la preuve : les preuves par excellence sont celles qui reflètent l’ordre de la fondation objective. Dans cet article nous faisons état des problèmes liés à une telle conception et argumentons en faveur d’une démarcation plus stricte entre la préoccupation ontologique et la préoccupation épistémologique dans l’élaboration d’une théorie de la preuve.Bolzano was the first to establish an explicit distinction between the deductive methods that allow us to recognise the certainty of a given truth and those that provide its objective ground. His conception of the relation between what we, in this paper, call “subjective consequence”, i.e. the relation from epistemic reason to consequence and “objective consequence”, i.e. grounding however suggests that Bolzano advocated an “explicativist” conception of proof : proofs par excellence are those that reflect the objective order of grounding. In this paper, we expose the problems involved by such a conception and argue in favour of a more rigorous demarcation between the ontological and the epistemological concern in the elaboration of a theory of proof. (shrink)

Les sciences cognitives poursuivent un objectif fort ancien, qui consiste, sommairement dit, à décrire et à expliquer les comportements intelligents. Elles appliquent à cet effet des principes méthodologiques moins traditionnels, dont l'adoption définit ce qu'il est convenu d'appeler le "tournant cognitif". Je me propose ici d'exposer brièvement ces principes, de les illustrer par des exemples appropriés et d’en discuter la signification philosophique. Pour l’essentiel, j’ai mis en avant un domaine qui me semble particulièrement pertinent pour les philosophes: l'analyse de la (...) catégorisation, c'est-à-dire du processus par lequel un ensemble d'entités (stimuli sonores ou visuels, objets concrets ou abstraits) en vient à être classifié en catégories séparées, qui peuvent être de type perceptif (phonèmes, couleurs) ou conceptuel (espèces naturelles, types d'événements, catégories esthétiques et morales). (shrink)

Beth has tried to vindicate the kantian doctrine of mathematical intuition in the frame of contemporary logic. The paper proposes a critical evaluation of this attempt. The theory of mathematical intuition that is exposed in the Critic of Pure Reason is twofold: on one hand, the intuition of the "first principles", as it is analyzed in the Aesthetics, on the other hand, the intuition which is involved in the proofs, as it is analyzed in the Methodology. Contrasting with most defenders (...) of Kant, who try to show that the first kind of intuition remains, in some way, compatible with the non-euclidean geometries, Beth wants to defend the second kind of intuition, by suggesting that it is nothing else than the "instanciation" method, well-known in the predicate calculus. I show that this strategy of defending Kant is unsuccessful. (shrink)

W ciągu 30 lat dokonała się głęboka przemiana w relacji między Internetem a aktywnością naukową. Nastąpiło przesunięcie funkcji Internetu, który przestał być jedynie instrumentem współpracy akademickiej, a stał się również narzędziem używanym przez media społecznościowe, zezwalające na maksymalną dyfuzję irracjonalizmu i starego faktualizmu. Aby zrozumieć tę przemianę, należy ponownie zbadać mechanizmy zbieżności opinii. Wynika ona z istnienia wspólnego świata, który ukazuje nam te same fakty i determinuje nieustanną rewizję przekonań każdej osoby. W tym procesie asymptotycznej zbieżności opinii nie wymaga się (...) żadnej komunikacji między jednostkami. Oczywiście, jeśli fakty znane przez jednych są komunikowane innym, konwergencja znacznie przyspiesza, i to tak bardzo, że wiedzę musimy ująć jako rezultat zbiorowej aktywności, w której wymiana informacji jest jednym z jej istotnych źródeł. Z jednej strony takie poznawcze współdziałanie wydaje się naturalne i łatwe do implementacji. Biorąc pod uwagę właściwości informacji, które przechowujemy, nawet jeśli je udostępniamy, to dzielenie się informacją przestaje być przedmiotem zwykłych trudności związanych ze współpracą. Z drugiej strony takie współdziałanie jest produktywne z samej natury: współpraca między kimś, kto zna φ, i kimś, kto wie, że φ implikuje ψ u obydwu jako mających wiedzę ψ, której żaden z nich nie posiadał przed wymianą informacji. Wczesny Internet pozwolił na ekstremalną intensywność tej informacyjnej współpracy. Obecnie mamy do czynienia z odmienną sytuacją. Poszczególne wyznaczniki rosnącej porowatości między naukowcami a opinią publiczną wzmocniły rolę wymiany. Nie jest to już wymiana informacji, lecz wymiana opinii. Stronniczość tkwiąca w naturze ludzkiej, a szczególnie potwierdzenie tej stronniczości, prowadzi do odwrócenia relacji między faktami a opiniami. Szukamy faktów potwierdzających podzielane przez nas opinie, wątpiąc w te, które ich nie określają, i tworzymy fakty do potwierdzenia tego, o czym jesteśmy przekonani. Dlatego przechodzimy od współdziałania do przynależności, dzieląc Internet na homogeniczne grupy wyznawców. (shrink)

Résumé. En trente ans, le rapport d’Internet à l’entreprise scientifique a changé. Nous sommes passés d’un instrument de collaboration scientifique à un dispositif de réseaux sociaux qui assure la plus large diffusion à l’irrationalisme et à l’alt-factualisme. Pour comprendre ce changement, il convient de réexaminer les mécanismes de la convergence des opinions. La première source de cette convergence est l’existence d’un monde commun, qui nous expose aux mêmes faits et qui détermine par révision successive des croyances de chacun, sans que (...) la moindre communication soit requise, une convergence asymptotique des opinions, et ce quelles que soient les croyances de départ. Naturellement, si les faits connus par les uns sont communiqués aux autres, cette convergence s’accélère considérablement, si bien que nous devons considérer la connaissance comme le résultat d’une activité collective, et l’échange d’informations comme l’une de ses sources nécessaires. D’une part, cette coopération épistémique est naturelle et facilement implémentable : en vertu des propriétés caractéristiques de l’information, qui est un bien que nous conservons lorsque nous le donnons, le partage informationnel est exempt des difficultés qui affectent généralement la coopération. D’autre part, cette coopération est intrinsèquement productive : la collaboration entre celui qui sait que φ et celui qui sait que φ implique ψ met chacun des deux agents en possession de la connaissance de ψ, qui n’était pourtant détenue par personne avant l’échange. L’internet des débuts donne à cette coopération informationnelle une ampleur inégalée. La situation actuelle est différente. Un certain nombre de facteurs, dont la porosité croissante entre les scientifiques et le large public, ont mis au premier plan l’échange, non des informations factuelles, mais celui des opinions. Les biais notoires de la psychologie humaine, au premier rang desquels le biais de confirmation, tendent à inverser le rapport entre les faits et les opinions. On cherche les faits confirmant les opinions entretenues, on met en doute les faits récalcitrants et l’on crée des faits corroborants. En bref, on passe d’une problématique de la coopération à une logique de l’affiliation, segmentant l’internet en groupes doxastiques homogènes. (shrink)

RésuméSelon K. Gödel, les restrictions méthodologiques des constructivistes sont aberrantes, et le point de vue réaliste est beaucoup plus fécond: il est hi‐même parvenu à ses résultats logiques fondarnentaux en donnant une place à la notion de vérite, qui n'est pas de type combinatoire. Le premier théorème d'incomplétude est hi‐même un argument décisif en faveur du réalisme, si l'on accepte le principe d'«accessibilité» en vertu duquel nous pouvons décider de toutes les propriétés de nos constructions intellectuelles. Par ailleurs, il existe (...) un large spectre d'arguments permettant de statuer sur un énoncé indécidable dans un système formel. La thèse mécaniste, selon laquelle l'intelligence humaine peut être pensée sans distorsion significative sur le modèle d'une machine de Turing, est donc inacceptable.SummaryAccording to K. Gödel, the methodological restrictions of the constructivists are aberrant, and the realist point of view is much more fruitful. He reached these fundamental logical results himself by making place for a non‐cornbinatorial notion of truth. The first incompletness theorem is itself a decisive argument in favor of realism, provided that the principle of «accessibility» is accepted, by virtue of which we are capable of determining all the properties of our intellectual constructions. Moreover, there are numerous arguments that permit the evaluation of an undecidable statement in a formal system. The mechanistic thesis, according to which the functioning of the human mind, without significant distorsion, can be compared to a Turing machine, is now unacceptable.ZusammenfassungNach Gödel sind die methodologischen Einschränkungen der Konstruktivisten irrig, und er hält den realistischen Standpuukt für viel fruchtbarer. Er selbst erreichte seine grundlegenden logischen Ergebnisse dadurch, dass er Platz machte für einen nichtkombinatorischen Begriff der Wahrheit. Das erste Unvollständigkeitstheorem ist selbst ein entscheidendes Argument zugunsten des Realismus, sofern das «Zugänglichkeitsprinzip» akzeptiert wird, wonach wir fähig sind, alle Eigenschaften unserer intellektuellen Konstruktionen zu bestinmen. Zudem gibt es zahlreiche Argumente, die die Beurteilung einer unentscheidbaren Aussage in einem formalen System erlauben. Die mechanistische These, nach welcher das Funktionieren des menschlichen Geistes ohne wesentliche Verzerrung mit einer Turingmaschine verglichen werden kann, ist heute nicht mehr annehmbar. (shrink)

As regards cognitive capacities, the point of view of classical Artificial Intelligence has been much challenged by the so-called emergentist point of view. This paper attempts to outline,on the basis of logical considerations dealing with practical feasibility, a general theory of incompressible unfolding that is consonant with an old Leibnizian stance rather with the contemporary theory of complexity. I defend a variant of emergentism according to which any process that leads to endow a system with cognitive capacities is such an (...) incompressible unfolding. (shrink)

Im Hinblick auf den Herbrand'schen Satz für die Prädikatenlogik der ersten Stufe und auf die Lehre vom Beweisverfahren mit Rechenautomaten, die daraus folgt, wird ein Beweis als komputazional synthetisch bezeichnet, wenn er sich auf Objekte bezieht, die im erwiesenen Satz nicht erwähnt sind. Die mathematischen Beweise sind aber auch synthetisch in einem begrifflichen Sinne: die Kontrolle oder die Begrenzung der angewandten Begriffe — die sogenannte Methodenreinheit — ist im allgemeinen unerreichbar.

Im Hinblick auf den Herbrand'schen Satz für die Prädikatenlogik der ersten Stufe und auf die Lehre vom Beweisverfahren mit Rechenautomaten, die daraus folgt, wird ein Beweis als komputazional synthetisch bezeichnet, wenn er sich auf Objekte bezieht, die im erwiesenen Satz nicht erwähnt sind. Die mathematischen Beweise sind aber auch synthetisch in einem begrifflichen Sinne: die Kontrolle oder die Begrenzung der angewandten Begriffe — die sogenannte Methodenreinheit — ist im allgemeinen unerreichbar.

We generalize the concept of a cooperative non-transferable utility game by introducing a socially structured game. In a socially structured game every coalition of players can organize themselves according to one or more internal organizations to generate payoffs. Each admissible internal organization on a coalition yields a set of payoffs attainable by the members of this coalition. The strengths of the players within an internal organization depend on the structure of the internal organization and are represented by an exogenously given (...) power vector. More powerful players have the power to take away payoffs of the less powerful players as long as those latter players are not able to guarantee their payoffs by forming a different internal organization within some coalition in which they have more power.We introduce the socially stable core as a solution concept that contains those payoffs that are both stable in an economic sense, i.e., belong to the core of the underlying cooperative game, and stable in a social sense, i.e., payoffs are sustained by a collection of internal organizations of coalitions for which power is distributed over all players in a balanced way. The socially stable core is a subset and therefore a refinement of the core. We show by means of examples that in many cases the socially stable core is a very small subset of the core.We will state conditions for which the socially stable core is non-empty. In order to derive this result, we formulate a new intersection theorem that generalizes the KKMS intersection theorem. We also discuss the relationship between social stability and the wellknown concept of balancedness for NTU-games, a sufficient condition for non-emptiness of the core. In particular we give an example of a socially structured game that satisfies social stability and therefore has a non-empty core, but whose induced NTU-game does not satisfy balancedness in the general sense of Billera. (shrink)

The thymus has been an enigmatic organ for centuries. Its true function was revealed only in 1961 when it was shown to be responsible for the proper development of the immune system. This finding has revolutionized the science of immunology and has led to a better understanding of the mechanisms involved in resistance to infections and of the pathogenesis of autoimmune and immunodeficiency diseases.