Let A be a formula without implications, and Γ consist of formulas containing disjunction and falsity only negatively and implication only positively. Orevkov and Nadathur proved that classical derivability of A from Γ implies intuitionistic derivability, by a transformation of derivations in sequent calculi. We give a new proof of this result , where the input data are natural deduction proofs in long normal form involving stability axioms for relations; the proof gives a quadratic algorithm to remove the stability axioms. (...) This can be of interest for computational uses of classical proofs. (shrink)

This article presents a critical qualitative study of two opinion articles, written by two eminent scholars (Jürgen Habermas and Timothy Snyder), on the German government’s hesitant arms supply for Ukraine during the first phase of the Russian war of aggression in 2022. The main aim of the article is the uncovering of the discursive practices of critique performed by two major public intellectuals. This case study thus allows insights into the simplistic representation of the Russo-Ukrainian war in German elite media (...) discourse. The analysis focuses on actor representations and topic limitations and manipulations in the two op-eds. It is shown that both Habermas and Snyder use characteristic ways of social actor representations in their texts which exhibit their allegiances. Furthermore, both of them limit and change topics at the meso- and macro-levels of their texts in order to make their arguments sound. In closing, the critical potential of linguistic discourse analysis is shortly addressed by arguing that the context sensitive application of the categories for analyzing discourse can uncover the internal norms to which authors orient which makes them open for a critical analysis. (shrink)

That reality, and in particular the (dynamic) objects of signs, are independent of our thoughts or other representations is a crucial thesis of Peirce’s realism. On the other hand, his semiotics implies the claim that all reality and all real objects are real for us only because of the signs we use. Do these two claims contradict, even exclude, each other? I will argue that both Peirce’s metaphysics and his semiotics provide a natural via media: a structural account of the (...) openness of processes, featuring transitive relations, connects process ontology implicit in his evolutionary metaphysics and the relational, quasi-inferential features embodied in interpretational sequences of signs. It is shown that Peirce’s notion of a sign, its normative role and his account of the directional force of objects implies a sort of logical causality that supports the unity of objects. In this way sign sequences are able to relate flexibly sign use with contextually specified independent objects. That is to say, relational properties of object-oriented chains of interpretations provide sign users with a flexible, fallibilistic instrument able to capture by contingent identity relations (teridentity) of the identity of objects in changing situations. (shrink)

The way physics and other parts of science work can be explained in the framework of radical constructivism. However, this constructivist view itself shows that a uniquily accepted epistemology, constructivism or any other, would not be an advantage for the developmentof science. Unlike physics some parts of science successfully use constructivist concepts inside their theories. Because this is the case particularly in learning theory, constructivist ideas can help to improve physics teaching.

This essay ist based on Heinrich Rombach's conception of structural phenomenology, a conception not yet widely known in philosophy and not at all known in sociology. The implications for the social sciences of this conception are explicated, related to the well-known positions of Max Weber, Alfred Schütz, Thomas S. Kuhn, and then linked to the current methodological discussion in the field of sociology in West Germany. The resulting promising new possibilities for basic questions of theory construction in the social sciences, (...) but especially in sociology, are detailed and clarified with respect to the possibility and necessity of the various movements and conceptions of plurality, perspectivity and consciousness of cognition levels. (shrink)

Introducing the perplexed reader to a philosophy requires both a comprehensive understanding of the philosophy in question and a rigorous simplifying strategy. But clarity and accessibility come at a price: one has to cut down on complicated and perhaps unresolved lines of thought and arguments, stratifying the development of theoretical positions into a coherent and accessible narrative. This review will address both the success of this book as an introduction and, rather unjustly, those more complex topics that have been left (...) out and might be of interest to readers of this journal.First of all, let me say that Cornelis de Waal’s Peirce: A Guide for the Pexplexed is a very good introduction to Peirce’s.. (shrink)

G. Jäger gave in Arch. Math. Logik Grundlagenforsch. 24 , 49-62, a recursive notation system on a basis of a hierarchy Iαß of α-inaccessible regular ordinals using collapsing functions following W. Buchholz in Ann. Pure Appl. Logic 32 , 195-207. Jäger's system stops, when ordinals α with Iα0 = α enter. This border is now overcome by introducing additional a hierarchy Jαß of weakly inaccessible Mahlo numbers, which is defined similarly to the Jäger hierarchy. An ordinal μ is called Mahlo, (...) if every normal-function f : μ → μ has regular fixpoints. Collapsing is defined for both Mahlo and simply regular ordinals such that for every Mahlo ordinal μ out of the J-hierarchy Ψμα is a regular σ such that Iσ0 = σ. For these regular σ again collapsing functions Ψσ are defined. To get a proper systematical order into the collapsing procedure, a pair of ordinals is associated to σ and α, and the definition of Ψσα is given by recursion on a suitable well-ordering of these pairs. Thus a fairly large system of ordinal notations can be established. It seems rather straightforward, how to extend this setting further. (shrink)