David Hilbert was one of the great mathematicians who expounded the centrality of their subject in human thought. In this collection of essays, Wilfried Sieg frames Hilbert's foundational work, from 1890 to 1939, in a comprehensive way and integrates it with modern proof theoretic investigations.

I argue against Schroeder's explanation of pragmatic encroachment on knowledge. In section 1, I introduce pragmatic encroachment and point out that an explanation of it should avoid Pascalian considerations. In section 2, summarize the key aspects of Schroeder's explanation of pragmatic encroachment. In section 3, I argue that Schroeder's explanation faces a dilemma: it either allows for an objectionable form of Pascalian encroachment or it fails to be a fully general explanation of pragmatic encroachment.

Wilfred Sieg and Dirk Schlimm. Dedekind's Analysis of Number: Systems and Axioms.

Wilfred Sieg. Mechanical Procedures and Mathematical Experience.

A survey of Euclid's Elements, this text provides an understanding of the classical Greek conception of mathematics and its similarities to modern views as well as its differences. It focuses on philosophical, foundational, and logical questions — rather than strictly historical and mathematical issues — and features several helpful appendixes.

The Federation of Belgian companies is a confederation which groups 36 branch associations covering 30. 000 individual firms. About 85 % are small and medium-sizedfirms occupying less than 50 employees. The VBO/FEB is the most important exponent of the high degree of affiliation on the employers' side. The process of decision making reflects the structure of the federation. The mandate is defined in the board of the VBO/FEB, composed by a representative ofeach branch association. This representative holds his mandate on (...) the basis of the deliberations held in the elected board of his association. The guiding principle is consensus, which is not synonymous of unanimity. When a consistent and representative majority emerges from the debate, the members holding another opinion join that majority in a spirit ofemployers' solidarity. The decision making process aims in this way to combine efficiency and democracy. This is particularly important for the VBO/FEB, as that organisation not only acts as a lobby but also as a social partner able to conclude agreements. In the Belgian system, social partners are consulted by the authorities, because of their representativeness. It must however be clear that they may not interfere with the political decisions which in our democratic system rest with government and parliament. (shrink)

We establish by elementary proof-theoretic means the conservativeness of two subsystems of analysis over primitive recursive arithmetic. The one subsystem was introduced by Friedman [6], the other is a strengthened version of a theory of Minc [14]; each has been shown to be of considerable interest for both mathematical practice and metamathematical investigations. The foundational significance of such conservation results is clear: they provide a direct finitist justification of the part of mathematical practice formalizable in these subsystems. The results are (...) generalized to relate a hierarchy of subsystems, all contained in the theory of arithmetic properties, to a corresponding hierarchy of fragments of arithmetic. The proof theoretic tools employed there are used to re-establish in a uniform, elementary way relationships between various fragments of arithmetic due to Parsons, Paris and Kirby, and Friedman. (shrink)

It is a remarkable fact that Hilbert's programmatic papers from the 1920s still shape, almost exclusively, the standard contemporary perspective of his views concerning (the foundations of) mathematics; even his own, quite different work on the foundations of geometry and arithmetic from the late 1890s is often understood from that vantage point. My essay pursues one main goal, namely, to contrast Hilbert's formal axiomatic method from the early 1920s with his existential axiomatic approach from the 1890s. Such a contrast illuminates (...) the circuitous beginnings of the finitist consistency program and connects the complex emergence of existential axiomatics with transformations in mathematics and philosophy during the 19th century; the sheer complexity and methodological difficulties of the latter development are partially reflected in the well known, but not well understood correspondence between Frege and Hilbert. Taking seriously the goal of formalizing mathematics in an effective logical framework leads also to contemporary tasks, not just historical and systematic insights; those are briefly described as “one direction” for fascinating work. (shrink)

Bobier argued that hope is necessary for practical deliberation. I will demonstrate that Bobier’s argument for this thesis fails. The problem is that one of its main premisses rests on a sufficient condition for hoping that is subject to counterexamples. I consider two ways to save the argument, but show that they are unsuccessful in doing so.

Since their inception, the Perspectives in Logic and Lecture Notes in Logic series have published seminal works by leading logicians. Many of the original books in the series have been unavailable for years, but they are now in print once again. This volume, the fifteenth publication in the Lecture Notes in Logic series, collects papers presented at the symposium 'Reflections on the Foundations of Mathematics' held in celebration of Solomon Feferman's 70th birthday (The 'Feferfest') at Stanford University, California in 1988. (...) Feferman has shaped the field of foundational research for nearly half a century. These papers reflect his broad interests as well as his approach to foundational research, which emphasizes the solution of mathematical and philosophical problems. There are four sections, covering proof theoretic analysis, logic and computation, applicative and self-applicative theories, and philosophy of modern mathematical and logic thought. (shrink)

The past 20 years have seen dramatic rises in suicide rates in the United States and other countries around the world. These trends have been identified as a public health crisis in urgent need of new solutions and have spurred significant research efforts to improve our understanding of suicide and strategies to prevent it. Unfortunately, despite making significant contributions to the founding of suicidology – through Emile Durkheim’s classic Suicide (1897/1951) – sociology’s role has been less prominent in contemporary efforts (...) to address these tragic trends, though as we will show, sociological theories offer great promise for advancing our understanding of suicide and improving the efficacy of suicide prevention. Here, we review sociological theory and empirical research on suicide. We begin where all sociologists must: with Durkheim. However, we offer a more comprehensive understanding of Durkheim’s insights into suicide than the prior reviews provided by those in other disciplines. In so doing, we reveal the nuance and richness of Durkheim’s insights that have been largely lost in modern suicidology, despite being foundational to all sociological theories of suicide – even those that have moved beyond his model. We proceed to discuss broadly acknowledged limitations to Durkheim’s theory of suicide and review how more recent theoretical efforts have not only addressed those concerns, but have done so by bringing a larger swatch of sociology’s theoretical and empirical toolkit to bare on suicide. Specifically, we review how recent sociological theories of suicide have incorporated insights from social network theories, cultural sociology, sociology of emotions, and sociological social psychology to better theorize how the external social world matters to individual psychological pain and suffering. We conclude by making explicit bridges between sociological and psychological theories of suicide; by noting important limitations in knowledge about suicide – particularly regarding the roles of organizations, inequality, and intersectionality in suicide – that sociology is well situated to help address. (shrink)

Zuerst im 2CV, dann im umgebauten VW-Bus: Das Zürcher Fotografenpaar Margrit und Ernst Baumann, 1929 bzw. 1928 geboren, begann in den 1950er-Jahren rund um den Erdball zu reisen. Ihre Fotografien publizierten sie in Zeitschriften und Zeitungen wie Stern, Neue Zürcher Zeitung oder Das gelbe Heft und brachten so die Welt in die Wohnzimmer. Kosmopolitan und neugierig kamen sie zu Motiven mit Seltenheitswert: Farbporträts von Che Guevara gehören ebenso dazu wie Reportagen über die letzten Kopfjäger im ecuadorianischen Urwald. Ein Schwerpunkt dieser (...) reich bebilderten Doppelmonografie ist ihre Reise entlang der “Panamericana” 1957-1959, die Süd- und Nordamerika verbindet. Sie fotografierten Reportagen, Porträts und Landschaftsbilder und drehten den wohl ersten Farbfilm über den legendären Verkehrsweg. Dieser Film und ein Filporträt über die beiden Fotografen sind dem Buch auf DVD beigefügt. Das Buch präsentiert Funde aus ihrem Fotoarchiv - viele Bilder erstmals im Originalausschnitt - sowie Publikationen in Zeitschriften. Der Historiker und Schriftsteller Wilfried Meichtry erzählt vom ereignisreichen Leben des Paars, das sich zeitlebens als journalistische Handwerker verstanden hat. Der Fotohistoriker Markus Schürpf ordnet ihr Werk in die Foto- und Pressegeschichte ein, Nadine Olonetzky verfasst Begleittexte zu den Bildern. Eine Entdeckung in der Schweizer Fotogeschichte. (shrink)

Wilfried Sieg. Formal Systems, Church Turing Thesis, and Gödel's Theorems: Three Contributions to The MIT Encyclopedias of Cognitive Science.

English summary: Does pastoral care require ethical competence in order to fulfil its task properly? And, conversely, to what extent does ethical reflection require feedback from pastoral experience in order to remain true to life and of practical relevance? Wilfried Sturm examines the way hospital pastors deal with ethical challenges and conflict situations in neonatal clinics and enquires into the insights that can be gained from them for the relationship of pastoral care and ethics. German description: Braucht Seelsorge ethische (...) Kompetenz, um ihrem Auftrag gerecht zu werden? Inwiefern bedarf umgekehrt die ethische Reflexion der Ruckkopplung an seelsorgerliche Erfahrung, um lebensnah und praxisrelevant zu bleiben? Wilfried Sturm untersucht den Umgang von Klinikseelsorgerinnen und -seelsorgern mit ethischen Herausforderungen und Konfliktsituationen in der Fruh- und Neugeborenenmedizin und fragt, welche Einsichten sich daraus fur das Verhaltnis von Seelsorge und Ethik gewinnen lassen. (shrink)

It is a popular thought that emotions play an important epistemic role. Thus, a considerable number of philosophers find it compelling to suppose that emotions apprehend the value of objects and events in our surroundings. I refer to this view as the Epistemic View of emotion. In this paper, my concern is with a rivaling picture of emotion, which has so far received much less attention. On this account, emotions do not constitute a form of epistemic access to specific axiological (...) aspects of their objects. Instead it proposes that they are ways of taking a stand or position on the world. I refer to this as the Position-Taking View of emotion. Whilst some authors seem sympathetic to this view, this it has so far not been systematically motivated and elaborated. In this paper, I fill this gap and propose a more adequate account of our emotional engagement with the world than the predominant epistemic paradigm. I start by highlighting the specific way in which emotions are directed at something, which I contrast with the intentionality of perception and other forms of apprehension. I then go on to offer a specific account of the valence of emotion and show how this account and the directedness of emotions makes them intelligible as a way of taking a position on something. (shrink)

Herbrand's Theorem, in the form of $$\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle-}$}}{\exists } $$ -inversion lemmata for finitary and infinitary sequent calculi, is the crucial tool for the determination of the provably total function(al)s of a variety of theories. The theories are (second order extensions of) fragments of classical arithmetic; the classes of provably total functions include the elements of the Polynomial Hierarchy, the Grzegorczyk Hierarchy, and the extended Grzegorczyk Hierarchy $\mathfrak{E}^\alpha $ , α < ε0. A subsidiary aim of the paper is to show (...) that the proof theoretic methods used here are distinguished by technical elegance, conceptual clarity, and wide-ranging applicability. (shrink)

This essay presents a novel approach to specifying the meaning of the concept of populism, on the political position it occupies and on the nature of populism. Employing analytic techniques of concept clarification and recent analytic ideology critique, it develops populism as a political kind in three steps. First, it descriptively specifies the stereotype of populist platforms as identified in extant research and thereby delimits the peculiar political position populism occupies in representative democracies as neither inclusionary nor fascist. Second, it (...) specifies on this basis analytically–normatively the particular stance towards liberal representative democracy (in particular towards popular sovereignty and democratic legitimacy) that unifies populism’s political position and explains how populist politics can be compelling for democratic citizens. The normative core (populist ideology) turns out to require no more than two general principles of legitimizing political authority by elections. Surprisingly, it does not need a separate anti-pluralist or exclusionary commitment: it entails it. Third, this normative model allows a response to a contested question in the theoretical discussion, namely, whether populism (properly specified) can be democracy-enhancing. The article defends the negative answer in virtue of the normative core alone and does so as much vis-à-vis a minimal (purely electoral) as vis-à-vis a normatively ambitious (liberal) conception of democracy. The reconstruction of the normative core of populist ideology enables a novel argument to show that populism is incompatible with the continued democratic legitimation of political authority even in the normatively most austere conception of ‘electoral democracy’, not just with ‘liberal democracy’. Assuming a normatively more ambitious concept of democratic legitimation in terms of political autonomy, the model also produces an extremely direct argument showing that populists cannot fulfil their promise of ‘taking back control’ over political decision-making to the population. (shrink)

Dedekind’s structuralism is a crucial source for the structuralism of mathematical practice—with its focus on abstract concepts like groups and fields. It plays an equally central role for the structuralism of philosophical analysis—with its focus on particular mathematical objects like natural and real numbers. Tensions between these structuralisms are palpable in Dedekind’s work, but are resolved in his essay Was sind und was sollen die Zahlen? In a radical shift, Dedekind extends his mathematical approach to “the” natural numbers. He creates (...) the abstract concept of a simply infinite system, proves the existence of a “model”, insists on the stepwise derivation of theorems, and defines structure-preserving mappings between different systems that fall under the abstract concept. Crucial parts of these considerations were added, however, only to the penultimate manuscript, for example, the very concept of a simply infinite system. The methodological consequences of this radical shift are elucidated by an analysis of Dedekind’s metamathematics. Our analysis provides a deeper understanding of the essay and, in addition, illuminates its impact on the evolution of the axiomatic method and of “semantics” before Tarski. This understanding allows us to make connections to contemporary issues in the philosophy of mathematics and science. (shrink)

What is the cash value of Richard Rorty’s philosophy and politics of religion? This paper analyzes the political promise of Rorty’s shift from atheism to anticlericalism in the last decade of his life. It seeks to deliver primarily a concise summary of this shift, and of its transformative motivation. Then a critique of this shift is followed by the suggestion of a friendly amendment: its extension towards a pragmatic pluralism. The outlined Rortyan conception of a serene, and, at the same (...) time robust, politics of religion is proposed as a promising answer to the question of how secular liberal citizens should react to the “return of the gods.”. (shrink)

Religious sects and their practices have become highly topical in the recent past in Germany. The call for criminal sanctions in order to tackle actual or presumed misconduct is becoming louder and louder. The author, a criminal law professor, analyses the present discussion and puts it into a constitutional law perspective. Any civil society that aims to optimise the scope of the personal freedoms of its members must withstand the temptation of creating a special regime of criminal law rules just (...) to combat religious sects and their practices. Criminal law has tobe applied uniformly in the whole society. Therfore, criminal sanctions can only be handed out, when practices infringe intolerably with the individual' s rights protected by the law. (shrink)

In this paper we give a new and comparatively simple proof of the following theorem by Girard [1]:“If ∀x∈ ${\cal O}$ ∃y∈ ${\cal O}$ ψ(x,y) (where the relationψ is arithmetic and positive in Kleene's ${\cal O}$ ), then there exists a recursive DilatorD such that ∀α≧ω∀x∈ ${\cal O}$ <α∃y∈ ${\cal O}$ (...) modification of Girard's system in [1]) we construct in a uniform way for each ordinalα a derivation Tα of the formula ∀x ∈ ${\cal O}$ <α∃y∈ ${\cal O}$ ψ(x, y), and then defineD immediately from the family (Tα)α∈On. Especially we set D(α):=Kleene-Brouwer length of (Tα). (shrink)

Thema der vorliegenden Arbeit ist der dialektische Gehalt der wichtigsten bildungstheoretischen Abhandlungen des padagogischen Theoretikers Josef Derbolav. Ergebnis der zum grossten Teil immanent durchgefuhrten Analyse ist der Aufweis, dass Derbolav die dialektische Fassung didaktischer, anthropologischer und handlungstheoretischer Prinzipien aufgrund metaphysischer Denkstrukturen nicht oder nur teilweise gelingt. Inwieweit einige dieser Prinzipien dialektisches Potential enthalten konnten, zeigt der Verfasser anhand der Entwicklung eines eigenen, an der hermeneutischen Philosophie orientierten dialektischen Standpunktes.".

The incompleteness theorems constitute the mathematical core of Gödel’s philosophical challenge. They are given in their “most satisfactory form”, as Gödel saw it, when the formality of theories to which they apply is characterized via Turing machines. These machines codify human mechanical procedures that can be carried out without appealing to higher cognitive capacities. The question naturally arises, whether the theorems justify the claim that the human mind has mathematical abilities that are not shared by any machine. Turing admits that (...) non-mechanical steps of intuition are needed to transcend particular formal theories. Thus, there is a substantive point in comparing Turing’s views with Gödel’s that is expressed by the assertion, “The human mind infinitely surpasses any finite machine”. The parallelisms and tensions between their views are taken as an inspiration for beginning to explore, computationally, the capacities of the human mathematical mind. (shrink)

Hilbert's finitist program was not created at the beginning of the twenties solely to counteract Brouwer's intuitionism, but rather emerged out of broad philosophical reflections on the foundations of mathematics and out of detailed logical work; that is evident from notes of lecture courses that were given by Hilbert and prepared in collaboration with Bernays during the period from 1917 to 1922. These notes reveal a dialectic progression from a critical logicism through a radical constructivism toward finitism; the progression has (...) to be seen against the background of the stunning presentation of mathematical logic in the lectures given during the winter term 1917/18. In this paper, I sketch the connection of Hilbert's considerations to issues in the foundations of mathematics during the second half of the 19th century, describe the work that laid the basis of modern mathematical logic, and analyze the first steps in the new subject of proof theory. A revision of the standard view of Hilbert's and Bernays's contributions to the foundational discussion in our century has long been overdue. It is almost scandalous that their carefully worked out notes have not been used yet to understand more accurately the evolution of modern logic in general and of Hilbert's Program in particular. One conclusion will be obvious: the dogmatic formalist Hilbert is a figment of historical (de)construction! Indeed, the study and analysis of these lectures reveal a depth of mathematical-logical achievement and of philosophical reflection that is remarkable. In the course of my presentation many questions are raised and many more can be explored; thus, I hope this paper will stimulate interest for new historical and systematic work. (shrink)

Dedekind's mathematical work is integral to the transformation of mathematics in the nineteenth century and crucial for the emergence of structuralist mathematics in the twentieth century. We investigate the essential components of what Emmy Noether called, his ‘axiomatic standpoint’: abstract concepts, models, and mappings.

Wilfried Sieg and John Byrnes. AnModel for Parallel Computation: Gandy's Thesis.

ArgumentIn 1877, a young mathematician named Joseph Boussinesq presented amémoireto theAcadémiedes sciences which demonstrated that some differential equations may have more than one solution. Boussinesq linked this fact to indeterminism and to a possible solution to the free will versus determinism debate. Boussinesq's main interest was to reconcile his philosophical and religious views with science by showing that matter and motion do not suffice to explain all there is in the world. His argument received mixed criticism that addressed both his (...) philosophical views and the scientific content of his work, pointing to the physical “realisticness” of multiple solutions. While Boussinesq proved to be able to face the philosophical criticism, the scientific objections became a serious problem, thus slowly moving the focus of the debate from the philosophical plane to the scientific one. This change of perspective implied a wide discussion on topics such as instability, the sensitivity to initial conditions, and the conservation of energy. The Boussinesq debate is an example of a philosophically motivated debate that transforms into a scientific one, an example of the influence of philosophy on the development of science. (shrink)