Structural completeness properties are investigated for a range of popular t-norm based fuzzy logics—including Łukasiewicz Logic, Gödel Logic, Product Logic, and Hájek's Basic Logic—and their fragments. General methods are defined and used to establish these properties or exhibit their failure, solving a number of open problems.

In the last few decades many formal systems of fuzzy logics have been developed. Since the main differences between fuzzy and classical logics lie at the propositional level, the fuzzy predicate logics have developed more slowly (compared to the propositional ones). In this text we aim to promote interest in fuzzy predicate logics by contributing to the model theory of fuzzy predicate logics. First, we generalize the completeness theorem, then we use it to get results on conservative extensions of theories (...) and on witnessed models. (shrink)

This paper addresses the ontological status of the body in the context of bodily practices in body-oriented disciplines, such as sport training, dance, and physiotherapy. Following Descartes’, Huss...

This monograph presents a general theory of weakly implicative logics, a family covering a vast number of non-classical logics studied in the literature, concentrating mainly on the abstract study of the relationship between logics and their algebraic semantics. It can also serve as an introduction to algebraic logic, both propositional and first-order, with special attention paid to the role of implication, lattice and residuated connectives, and generalized disjunctions. Based on their recent work, the authors develop a powerful uniform framework for (...) the study of non-classical logics. In a self-contained and didactic style, starting from very elementary notions, they build a general theory with a substantial number of abstract results. The theory is then applied to obtain numerous results for prominent families of logics and their algebraic counterparts, in particular for superintuitionistic, modal, substructural, fuzzy, and relevant logics. The book may be of interest to a wide audience, especially students and scholars in the fields of mathematics, philosophy, computer science, or related areas, looking for an introduction to a general theory of non-classical logics and their algebraic semantics. (shrink)

Shows how different forms of skepticism can lead to remarkably different moral and political implications.

In this book, Petre Petrov argues that Soviet ideology, in the form in which it solidified during the Stalinist period, should not be seen as a member of a known political ideology. Rather, Soviet ideology is its own kind of political ideology, whose original life calls for an innovative conceptual treatment.

Objectivity, as one of the key attributes of science, has become an indispensable part of its ethos and a central theme of the philosophy of science. As such, it has been a subject of philosophical reflection by a number of authors. In our project – in which both philosophers of science and scientists participate – we examine the concept of objectivity in the natural sciences with the tools of experimental philosophy. We aim to identify specific operational dimensions of objectivity, those (...) with which current scientist actually work, thus making them accessible for further theoretical analysis and research. In this text, we present results from the first, qualitative phase of our research based on in-depth interviews and focus groups with scientists working in the Czech Republic. Further, we confront this empirical data with theoretical notions of objectivity. We also present other findings from the research and formulate hypotheses for the research’s subsequent phases. (shrink)

A simple complete axiomatic system is presented for the many-valued propositional logic based on the conjunction interpreted as product, the coresponding implication (Goguen's implication) and the corresponding negation (Gödel's negation). Algebraic proof methods are used. The meaning for fuzzy logic (in the narrow sense) is shortly discussed.

We are thankful to Gerhard Schurz for his response (Schurz 2023) to our paper (Spelda et al. 2023). Spelda et al. (2023) shows how a variant of no-regret learning called meta-induction (Schurz 2008; 2019) can be used for optimal selection from available political alternatives and, as a result, also for increasing voter competence that has come under attack from mis/disinformation. Since our paper takes a first step in applying meta-induction to long-standing issues in Democratic Theory (e.g., the usefulness of jury (...) theorems for justifying democracy), we are grateful to Gerhard Schurz for highlighting some of the conditions that need to be met for the development of practical applications. (shrink)

Can one extend crisp Peano arithmetic PA by a possibly many-valued predicate Tr(x) saying "x is true" and satisfying the "dequotation schema" $\varphi \equiv \text{Tr}(\bar{\varphi})$ for all sentences φ? This problem is investigated in the frame of Lukasiewicz infinitely valued logic.

Die 1922 in Der jüdische Student im Berliner Verlag Ferdinand Ostertag publizierte Schrift Die Idee der Zerstreuung und Widersammlung bei den Propheten war die erste Veröffentlichung von Hans Jonas. Zur Zeit der Verfassung des Textes war Jonas Mitglied in der 1906 gegründeten jüdischen Studentenvereinigung Maccabaea, der er vom Herbst 1921 bis Frühjahr 1923 angehörte. Der Staat Israel existierte noch nicht, das heutige Staatsgebiet stand seit dem Zusammenbruch des Osmanischen Reiches 1920 unter britischem Mandat.

An arithmetical interpretation of dynamic propositional logic (DPL) is a mapping f satisfying the following: (1) f associates with each formula A of DPL a sentence f(A) of Peano arithmetic (PA) and with each program α a formula f(α) of PA with one free variable describing formally a supertheory of PA; (2) f commutes with logical connectives; (3) f([α] A) is the sentence saying that f(A) is provable in the theory f(α); (4) for each axiom A of DPL, f(A) is (...) provable in PA (and consequently, for each A provable in DPL, f(A) is provable in PA). The arithmetical completeness theorem is proved saying that a formula A of DPL is provable in DPL iff for each arithmetical interpretation f, f(A) is provable in PA. Various modifications of this result are considered. (shrink)

The paper presents a particular example of a formula which is a standard tautology of Łukasiewicz but not its general tautology; an example of a model in which the formula is not true is explicitly constructed. Analogous example of a formula and its model is given for product logic.

This paper is a contribution to the study of the rôle of disjunction inAlgebraic Logic. Several kinds of (generalized) disjunctions, usually defined using a suitable variant of the proof by cases property, were introduced and extensively studied in the literature mainly in the context of finitary logics. The goals of this paper are to extend these results to all logics, to systematize the multitude of notions of disjunction (both those already considered in the literature and those introduced in this paper), (...) and to show several interesting applications allowed by the presence of a suitable disjunction in a given logic. (shrink)

Axiomatic set theory with full comprehension is known to be consistent in Łukasiewicz fuzzy predicate logic. But we cannot assume the existence of natural numbers satisfying a simple schema of induction; this extension is shown to be inconsistent.

The paper deals with the problem whether there can exist indeterminate identity. If one accepts Evans’s argument, then statements about indeterminate identity can be true, but only those, in which at least one of the singular terms does not refer determinately. One does not have to explain all vagueness as semantic, i.e. as indeterminacy of meaning, because some such statements can be true on account of indeterminacy of reality. This can be shown in the particular quantum case introduced by Lowe (...) concerning the identity of an absorbed and emitted electron. The singular terms within the identity statements in this example are to be understood in the way pointed out by Abasnezhad and in the manner Barnes and Williams take names in statements of identity between Kilimanjaro and one of the precise aggregates of particles of which the mountain consists: One of the names refers indeterminately. This indeterminacy is of the kind belonging to indefinite descriptions. The issue of individuality on quantum level can be understood using resources of structural realism of James Ladyman. (shrink)

The article is a critical systematic presentation of R. M. Hare's ethical concepts and doctrine as outlined in his books The Language of Morals (1952) and Freedom and Reason (1963). The theory merits attention for many reasons, yet it appears to suffer from some weaknesses; the chief among them being the lack of explanation for the source of binding force of moral principles.

This article identifies the assumption of responsibility as a basic need of human beings and applies the concept specifically to older people with dementia or Alzheimer's disease. It suggests a two‐level concept of responsibility, based on the approach of discourse ethicist Karl‐Otto Apel, as a promising approach to recognizing human diversity while at the same time respecting people's equal rights to participate in discourse. This concept can serve as a theoretical starting point for the construction of individually adapted types of (...) responsibility. Furthermore, the article describes practical ideas (primarily the practice of doll therapy) that can enable people with dementia or Alzheimer's disease to assume responsibility. Direct communication and a reflective, sensitive consideration of each individual case are identified as important prerequisites for the inclusion of elderly people with dementia. (shrink)

[Anthony Kenny: Thomas on the Human Spirit].

The paper discusses one of the central problems of contemporary formal semantics — counterexamples to the predictions of the theory of binding (due to N. Chomsky). In particular, the author addresses cases of the so-called coreferential readings of reflexive pronouns which are standardly predicted to receive only the bound reading. The author examines theories of T. Reinhart and I. Heim and suggests an extension ofthe latter theory in order to enable it to account for the aforementioned readings of reflexive pronouns.

This article provides an analysis—within the framework of Radical Construction Grammar—of how become developed into a copula ‘become’ out of an original sense ‘arrive’, and wax, originally ‘grow’, also came to be used as a copula ‘become’. Importantly, it explains why these verbs successfully became fully productive copulas in a very short period of time. It is argued that this happened after a pre-copular stage had reached a cognitive threshold value. The occurrence of this threshold is related to the fact (...) that the copular constructions featuring become and wax were not the end result of a single diachronic lineage of constructions (i.e. one construction developed out of another one, one at a time). Instead, the copularization of these verbs was the result of an interaction between lineages of constructions, belonging to two groups: (i) constructions involving become or wax, which gradually changed and interacted with each other; (ii) constructions involving already existing copulas, notably weorđan ‘become’, which provided a generally productive analog upon which the newly emerging copulas could graft. Generally, the article calls attention to the importance of multiple source constructions and thresholds in understanding grammaticalization processes and productivity. (shrink)

Uniform infinite bases are defined for the single-conclusion and multiple-conclusion admissible rules of the implication–negation fragments of intuitionistic logic and its consistent axiomatic extensions . A Kripke semantics characterization is given for the structurally complete implication–negation fragments of intermediate logics, and it is shown that the admissible rules of this fragment of form a PSPACE-complete set and have no finite basis.

On the Notion "Type of Language" Petr Sgall It is well known that the high frequency of terminological vagueness and confusion has been a serious obstacle ...

We give a brief introduction to the axiomatization of temporal logics. Branching continuations are shortly presented thereafter and the possibility of their clear syntactical axiomatization in a Hilbert-style system is investigated as last. Some basic preliminary observations and suggestions, how such axiomatization could start, are presented.

Substructural logics extending the full Lambek calculus FL have largely benefited from a systematical algebraic approach based on the study of their algebraic counterparts: residuated lattices. Recently, a nonassociative generalization of FL has been studied by Galatos and Ono as the logic of lattice-ordered residuated unital groupoids. This paper is based on an alternative Hilbert-style presentation for SL which is almost MP -based. This presentation is then used to obtain, in a uniform way applicable to most substructural logics, a form (...) of local deduction theorem, description of filter generation, and proper forms of generalized disjunctions. A special stress is put on semilinear substructural logics. Axiomatizations of the weakest semilinear logic over SL and other prominent substructural logics are provided and their completeness with respect to chains defined over the real unit interval is proved. (shrink)

Drawing on current debates at the frontiers of economics, psychology, and political philosophy, this book explores the challenges that arise for liberal democracies from a confrontation between modern technologies and the bounds of human rationality. With the ongoing transition of democracy's underlying information economy into the digital space, threats of disinformation and runaway political polarization have been gaining prominence. Employing the economic approach informed by behavioral sciences' findings, the book's chief concern is how these challenges can be addressed while preserving (...) a commitment to democratic values and maximizing the epistemic benefits of democratic decision-making. The book has two key strands: it provides a systematic argument for building a behaviorally informed theory of democracy; and explores how scientific knowledge on quirks and bounds of human rationality can inform the design of resilient democratic institutions. Drawing these together, the book explores the centrality of the rationality assumption in the methodological debates surrounding behavioral sciences as exemplified by the dispute between neoclassical and behavioral economics; the role of rationality in democratic social choice; behaviorally informed paternalism as a response to the challenge of irrationality; and non-paternalistic avenues to increase the resilience of the democratic institutions towards political irrationality This book is invaluable reading for anyone interested in behavioral economics and sciences, political philosophy and the future of democracy. (shrink)

This paper is a contribution to Mathematical fuzzy logic, in particular to the algebraic study of t-norm based fuzzy logics. In the general framework of propositional core and Δ-core fuzzy logics we consider three properties of completeness with respect to any semantics of linearly ordered algebras. Useful algebraic characterizations of these completeness properties are obtained and their relations are studied. Moreover, we concentrate on five kinds of distinguished semantics for these logics–namely the class of algebras defined over the real unit (...) interval, the rational unit interval, the hyperreals , the strict hyperreals and finite chains, respectively–and we survey the known completeness methods and results for prominent logics. We also obtain new interesting relations between the real, rational and hyperreal semantics, and good characterizations for the completeness with respect to the semantics of finite chains. Finally, all completeness properties and distinguished semantics are also considered for the first-order versions of the logics where a number of new results are proved. (shrink)