In this work we propose a labelled tableau method for Łukasiewicz infinite-valued logic Lω. The method is based on the Kripke semantics of this logic developed by Urquhart [25] and Scott [24]. On the one hand, our method falls under the general paradigm of labelled deduction [8] and it is rather close to the tableau systems for sub-structural logics proposed in [4]. On the other hand, it provides a CoNP decision procedure for Lω validity by reducing the check of branch (...) closure to linear programming. (shrink)

In this work we propose a labelled tableau method for ukasiewicz infinite-valued logic L . The method is based on the Kripke semantics of this logic developed by Urquhart [25] and Scott [24]. On the one hand, our method falls under the general paradigm of labelled deduction [8] and it is rather close to the tableau systems for sub-structural logics proposed in [4]. On the other hand, it provides a CoNP decision procedure for L validity by reducing the check of (...) branch closure to linear programming. (shrink)

We define a family of intuitionistic non-normal modal logics; they can be seen as intuitionistic counterparts of classical ones. We first consider monomodal logics, which contain only Necessity or Possibility. We then consider the more important case of bimodal logics, which contain both modal operators. In this case we define several interactions between Necessity and Possibility of increasing strength, although weaker than duality. We thereby obtain a lattice of 24 distinct bimodal logics. For all logics we provide both a Hilbert (...) axiomatisation and a cut-free sequent calculus, on its basis we also prove their decidability. We then define a semantic characterisation of our logics in terms of neighbourhood models containing two distinct neighbourhood functions corresponding to the two modalities. Our semantic framework captures modularly not only our systems but also already known intuitionistic non-normal modal logics such as Constructive K and the propositional fragment of Wijesekera’s Constructive Concurrent Dynamic Logic. (shrink)

The aim of this work is to develop a declarative semantics for N-Prolog with negation as failure. N-Prolog is an extension of Prolog proposed by Gabbay and Reyle, which allows for occurrences of nested implications in both goals and clauses. Our starting point is an operational semantics of the language defined by means of top-down derivation trees. Negation as finite failure can be naturally introduced in this context. A goal-G may be inferred from a database if every top-down derivation of (...) G from the database finitely fails, i.e., contains a failure node at finite height.Our purpose is to give a logical interpretation of the underlying operational semantics. In the present work we take into consideration only the basic problems of determining such an interpretation, so that our analysis will concentrate on the propositional case. Nevertheless we give an intuitive account of how to extend our results to a first order language. A full treatment of N-Prolog with quantifiers will be deferred to the second part of this work. (shrink)

In this paper we focus on theorem proving for conditional logics. First, we give a detailed description of CondLean, a theorem prover for some standard conditional logics. CondLean is a SICStus Prolog implementation of some labeled sequent calculi for conditional logics recently introduced. It is inspired to the so called “lean” methodology, even if it does not fit this style in a rigorous manner. CondLean also comprises a graphical interface written in Java. Furthermore, we introduce a goal-directed proof search mechanism, (...) derived from the above mentioned sequent calculi based on the notion of uniform proofs. Finally, we describe GOALDUCK, a simple SICStus Prolog implementation of the goal-directed calculus mentioned here above. Both the programs CondLean and GOALDUCK, together with their source code, are available for free download at. (shrink)

Fuzzy logics are many-valued logics that are well suited to reasoning in the context of vagueness. They provide the basis for the wider field of Fuzzy Logic, encompassing diverse areas such as fuzzy control, fuzzy databases, and fuzzy mathematics. This book provides an accessible and up-to-date introduction to this fast-growing and increasingly popular area. It focuses in particular on the development and applications of "proof-theoretic" presentations of fuzzy logics; the result of more than ten years of intensive work by researchers (...) in the area, including the authors. In addition to providing alternative elegant presentations of fuzzy logics, proof-theoretic methods are useful for addressing theoretical problems and developing efficient deduction and decision algorithms. Proof-theoretic presentations also place fuzzy logics in the broader landscape of non-classical logics, revealing deep relations with other logics studied in Computer Science, Mathematics, and Philosophy. The book builds methodically from the semantic origins of fuzzy logics to proof-theoretic presentations such as Hilbert and Gentzen systems, introducing both theoretical and practical applications of these presentations. (shrink)

Product logic Π is an important t-norm based fuzzy logic with conjunction interpreted as multiplication on the real unit interval [0,1], while Cancellative hoop logic CHL is a related logic with connectives interpreted as for Π but on the real unit interval with 0 removed (0,1]. Here we present several analytic proof systems for Π and CHL, including hypersequent calculi, co-NP labelled calculi and sequent calculi.

In this work we develop goal-directed deduction methods for the implicational fragment of several modal logics. We give sound and complete procedures for strict implication of K, T, K4, S4, K5, K45, KB, KTB, S5, G and for some intuitionistic variants. In order to achieve a uniform and concise presentation, we first develop our methods in the framework of Labelled Deductive Systems [Gabbay 96]. The proof systems we present are strongly analytical and satisfy a basic property of cut admissibility. We (...) then show that for most of the systems under consideration the labelling mechanism can be avoided by choosing an appropriate way of structuring theories. One peculiar feature of our proof systems is the use of restart rules which allow to re-ask the original goal of a deduction. In case of K, K4, S4 and G, we can eliminate such a rule, without loosing completeness. In all the other cases, by dropping such a rule, we get an intuitionistic variant of each system. The present results are part of a larger project of a goal directed proof theory for non-classical logics; the purpose of this project is to show that most implicational logics stem from slight variations of a unique deduction method, and from different ways of structuring theories. Moreover, the proof systems we present follow the logic programming style of deduction and seem promising for proof search [Gabbay and Reyle 84, Miller et al. 91]. (shrink)

The logic of Conditional Beliefs has been introduced by Board, Baltag, and Smets to reason about knowledge and revisable beliefs in a multi-agent setting. In this article both the semantics and the proof theory for this logic are studied. First, a natural semantics forCDLis defined in terms of neighbourhood models, a multi-agent generalisation of Lewis’ spheres models, and it is shown that the axiomatization ofCDLis sound and complete with respect to this semantics. Second, it is shown that the neighbourhood semantics (...) is equivalent to the original one defined in terms of plausibility models, by means of a direct correspondence between the two types of models. On the basis of neighbourhood semantics, a labelled sequent calculus forCDLis obtained. The calculus has strong proof-theoretic properties, in particular admissibility of contraction and cut, and it provides a decision procedure for the logic. Furthermore, its semantic completeness is used to obtain a constructive proof of the finite model property of the logic. Finally, it is shown that other doxastic operators can be easily captured within neighbourhood semantics. This fact provides further evidence of the naturalness of neighbourhood semantics for the analysis of epistemic/doxastic notions. (shrink)

We present logic programming style “goal-directed” proof methods for Łukasiewicz logic Ł that both have a logical interpretation, and provide a suitable basis for implementation. We introduce a basic version, similar to goal-directed calculi for other logics, and make refinements to improve efficiency and obtain termination. We then provide an algorithm for fuzzy logic programming in Rational Pavelka logic RPL, an extension of Ł with rational constants.

In this paper we propose a conditional logic called IBC to represent iterated belief revision systems. We propose a set of postulates for iterated revision which are a small variant of Darwiche and Pearl''s ones. The conditional logic IBC has a standard semantics in terms of selection function models and provides a natural representation of epistemic states. We establish a correspondence between iterated belief revision systems and IBC-models. Our representation theorem does not entail Gärdenfors'' Triviality Result.

In this paper we propoee a logic programming language which supports hypothetical updates together with integrity constraints. The language makes use of a revision mechanism, which is needed to restore consistency when an update violates some integrity constraint. The revision policy adopted is based on the simple idea that more recent information is preferred to earlier one. We show how this language can be used to represent and perform several types of defeasible reasoning. We develop a logical characterization of the (...) language in a three-valued conditional logic, by introducing a completion construction. We show that the operational semantics is sound and complete with respect to the completion construction. (shrink)

Taste as Experience puts the pleasure of food at the center of human experience. It shows how the sense of taste informs our preferences for and relationship to nature, pushes us toward ethical practices of consumption, and impresses upon us the importance of aesthetics. Eating is often dismissed as a necessary aspect of survival, and our personal enjoyment of food is considered a quirk. Nicola Perullo sees food as the only portion of the world we take in on a (...) daily basis, constituting our first and most significant encounter with the earth. Perullo has long observed people's food practices and has listened to their food experiences. He draws on years of research to explain the complex meanings behind our food choices and the thinking that accompanies our gustatory actions. He also considers our indifference toward food as a force influencing us as much as engagement. For Perullo, taste is value and wisdom. It cannot be reduced to mere chemical or cultural factors but embodies the quality and quantity of our earthly experience. (shrink)

In the historical context of a crisis in biological psychiatry, psychedelic drugs paired with psychotherapy are globally re-emerging in research clinics as a potential transdiagnostic therapy for treating mood disorders, addictions, and other forms of psychological distress. The treatments are poised to soon shift from clinical trials to widespread service delivery in places like Australia, North America, and Europe, which has prompted ethical questions by social scientists and bioethicists. Taking a broader view, we argue that the ethics of psychedelic therapy (...) concerns not simply how psychotherapies are different when paired with psychedelic drugs, but how psychedelic therapies shape and are shaped by different values, norms, and metaphysical commitments. Drawing from the published literature and interviews with seven psychedelic therapists working in clinical trials in the United States, Germany, Switzerland, and Australia, this article opens the black box of the treatments to consider the values and informal debates currently animating the therapies. Considering questions of patient autonomy, mechanisms of therapeutic action, and which therapies are best suited to pair with psychedelic substances, we examine the ethics of psychedelic therapy as an emergent form of life. To bring this form of life out in fuller relief, we conclude by comparing and contrasting it with ayahuasca use in Amazonian shamanism. (shrink)

This chapter deals with one of the common fallacies in Western philosophy, inappropriate appeal to authority (IAA). IAA has many different facets. At its core, it is a fallacy that assumes that because someone is an authority, we should listen to that person. The problem with IAA is that it ignores content in favor of credentials and power. There are a few different ways in which IAA can occur. IAA seems to be the result of a flaw in human thinking. (...) Social cognitive theory, a theory that helps explain human action, notes that humans tend to act like each other. The tendency to listen to authorities who are not authorities explains why celebrities are able to sell us stuff. The important thing to remember about IAA is that it is not just a fallacy that comes up in arguments that do not matter. (shrink)

Methexiology is not a particular theory, but rather a general philosophical orientation. Therefore, in Methexiology: Philosophical Theology and Theological Philosophy for the Deification of Humanity, Nicolas Laos elucidates the significance of methexiology for the study of ontology, epistemology, ethics, philosophical psychology, theory of justice, philosophy of history, and philosophy of religion. Laos argues that, faced with the modern and the postmodern crises of meaning, we need a new myth, a new spiritual formula, for the resacralization of humanity and the cosmos, (...) without restoring defunct totems, without using tales as "cheap" substitutes for the lack of a life-giving myth, and without negating history. In his Methexiology, Laos studies the "genealogy" of the modern and the postmodern crises of meaning, and, based on his new interpretation of classical Greek philosophy and Hesychasm, proposes methexiology as a way of overcoming the crises of meaning and as a way of resacralizing humanity and the cosmos through a new metaphysically grounded humanism. (shrink)

The empirical study of belief is emerging at a rapid clip, uniting work from all corners of cognitive science. Reliance on belief in understanding and predicting behavior is widespread. Examples can be found, inter alia, in the placebo, attribution theory, theory of mind, and comparative psychological literatures. Research on belief also provides evidence for robust generalizations, including about how we fix, store, and change our beliefs. Evidence supports the existence of a Spinozan system of belief fixation: one that is automatic (...) and independent of belief rejection. Independent research supports the existence of a system of fragmented belief storage: one that relies on large numbers of causally isolated, context-sensitive stores of belief in memory. Finally, empirical and observational data support at least two systems of belief change. One system adheres, mostly, to epistemological norms of updating; the other, the psychological immune system, functions to guard our most centrally held beliefs from potential inconsistency with newly formed beliefs. Refining our under- standing of these systems can shed light on pressing real-world issues, such as how fake news, propaganda, and brainwashing exploit our psychology of belief, and how best to construct our modern informational world. (shrink)

In recent years much research has been undertaken regarding the feasibility of the human uterine transplant as a treatment for absolute uterine factor infertility. Should it reach clinical application this procedure would allow such individuals what is often a much-desired opportunity to become not only social mothers, or genetic and social mothers but mothers in a social, genetic and gestational sense. Like many experimental transplantation procedures such as face, hand, corneal and larynx transplants, UTx as a therapeutic option falls firmly (...) into the camp of the quality of life transplant, undertaken with the aim, not to save a life, but to enrich one. However, unlike most of these novel procedures – where one would be unlikely to find a willing living donor or an ethics committee that would sanction such a donation – the organs to be transplanted in UTx are potentially available from both living and deceased donors. In this article, in the light of the recent nine-case research trial in Sweden which used uteri obtained from living donors, and the assertions on the part of a number of other research teams currently preparing trials that they will only be using deceased donors, I explore the question of whether, in the case of UTx, there exist compelling moral reasons to prefer the use of deceased donors despite the benefits that may be associated with the use of organs obtained from the living. (shrink)

Blaise Pascal est le penseur radical des limites et des contradictions de l'homme, ni ange ni bête. Contrairement à ce qu'en prétend l'orgueil de toute une modernité, la raison ne peut pas tout ; mais contrairement au désespoir du fanatisme, la raison n'est pas sans force. Jusqu'où alors peut-elle s'exercer? Pour Pascal, la philosophie ne saurait faire l'économie de la question de Dieu, Elle doit donc croiser la théologie. Mais comment vont se nouer l'ordre de l'esprit et celui de la (...) charité? Pascal produit ainsi une analyse critique de la philosophie comme telle, de ses capacités et de ses limites, que le présent ouvrage se donne pour tâche de clarifier. Que peut la philosophie? Mais qui décide de ce qu'elle peut, et surtout de ce qu'elle ne peut pas? Comment s'établissent alors ses rapports avec la théologie? Ce que Pascal nous invite ainsi à penser, c'est toujours à la fois la misère et la grandeur de la philosophie. (shrink)

Dans son dernier cours au Collège de France, Michel Foucault nous parle d'un oubli, plus fondamental à ses yeux que le fameux "oubli de l'être", ou plus précisément d'une négligence ; une négligence dont la philosophie est responsable, ce qui est d'autant plus paradoxal qu'il concerne précisément la vie philosophique. "Je voudrais, en tout cas, suggérer simplement que s'il est vrai que la question de l'être a bien été ce que la philosophie occidentale a oublié et dont l'oubli a rendu (...) possible la métaphysique, peut-être aussi la question de la vie philosophique n'a-t-elle pas cessé d'être, je ne dirais pas oubliée, mais négligée ; elle n'a pas cessé d'apparaître comme en trop par rapport à la philosophie, à la pratique philosophique, à un discours de plus en plus indexé au modèle scientifique" Cette négligence a une histoire. Car le problème de la vie philosophique a été posé dans toute sa radicalité dans l'Antiquité ; il n'était pas complètement oublié à l'époque moderne, comme en témoigne l'oeuvre de Spinoza ; mais à partir du moment "où la philosophie est devenue un métier de professeur, c'est-à-dire au début du XIXème siècle", elle a évacué du champ des problèmes pertinents, des problèmes "sérieux", cela même qui pourtant lui avait donné son horizon et sa raison d'être : la possibilité de définir une vie philosophique, c'est-à-dire une vie juste, une vie bonne, une "vraie vie". (shrink)

Die Utopien sind tot, es leben die Utopien. In diesem Buch wird die Utopie sozialer Gerechtigkeit entwickelt. INhaltlich besteht es in dem Dreischritt, (1) aus im Alltag von jedermann hin und wieder geauSSerten situativen Urteilen das gemeinsame Grundverstandnis von Gerechtigkeit zu destillieren, (2) anhand dieses Gelanders die bedeutendsten zeitgenossischen Theoretiker sozialer Gerechtigkeit akribisch zu lesen und in konstruktiver Absicht zu kritisieren, um (3) in ersten Ansatzen eine gerechtere Zukunftsgesellschaft zu skizzieren, deren quer zu tradierten Ideologien liegendes System sich ethischer Sozialismus (...) nennen lieSSe. (shrink)

This book advances a new interpretation of Hart's penal philosophy. Positioning itself in opposition to current interpretations, the book argues that Hart does not defend a mixed theory of punishment, nor a rule-utilitarian theory of punishment, nor a liberal form of utilitarianism, nor a goal and constraint approach. Rather, it is argued, his penal philosophy is based on his moral pluralism, which comprises two aspects: value pluralism and pluralism with respect to forms of moral reason. It is held that this (...) means, on the one hand, that criminal law has an irreducible complexity due to the compromises it makes to accommodate competing values, and on the other hand, that there need not be one single justification of punishment. This original interpretation is not based only on Hart's key volume on the subject Punishment and Responsibility, but on a careful reading of his complete works. The book will be a valuable resource for academics and researchers interested in Hart's philosophy, the philosophy of law and criminal law. (shrink)

Die Suche nach historischen Quellen für die Leibniz’sche Philosophie scheint zunächst unerschöpflich. Durch alle in diesem Band versammelten Arbeiten wird der Einfluss der Philosophie des Aristoteles auf das Leibniz’sche Denken näher umrissen. Ein wesentliches Ziel ist es hierbei, einen Beitrag zur Analyse dieser philosophischen Beziehung zu leisten und zu zeigen, dass auch Aristoteles’ Philosophie nach Ansicht unserer Autoren entscheidend zum Verständnis des Leibniz’schen Denkens beiträgt. Die Texte befassen sich mit wesentlichen Themen der Leibniz’schen Logik und Metaphysik, z. B. mit den (...) Grundbegriffen „Monade“ (und deren „Körperhaftigkeit“), „Entelechie“, „Nous“, mit dem Problem der Individuation (Individuum, Atomismus, Einheit), mit den substanziellen Formen, mit der Wissenschaft im Allgemeinen und der Technik, mit der Transformation der Logik, mit den Prinzipien (nämlich denjenigen des zureichenden Grundes, der Individuation und der Notwendigkeit), mit Zukunft und Kontingenz sowie Vergänglichkeit, mit der Theorie der syllogistischen Folgerung, usw. Diese Themen werden stets in der Gegenüberstellung von Leibniz und Aristoteles behandelt – sie zeigen daher, wie Leibniz aristotelische Thesen übernahm, veränderte oder kritisierte. The search for the historical sources of Leibniz’s philosphy initially seems to be unending. All the essays in this volume outline more clearly the influence of Aristotle’s philosophy on Leibniz’s thought. In this context a fundamental aim is to contribute to the analysis of this philosophical relationship and to demonstrate that Aristotle’s philosophy, in the opinion of our authors, plays a decisive role in the understanding of Leibniz’s thought. The texts address fundamental themes of Leibniz’s logic and metaphysics, e.g. the basic concepts of ‘monads’ (and their ‘corporality’), ‘entelechy’ and ‘nous; the problem of individuation (individual, atomism, unity); substantial forms; knowledge in general, and technology; the transformation of logic; principles (namely those of sufficient grounds, of individuation and of necesssity); future and contingency and transientness; the theory of syllogistic deduction, etc. These themes are regularly considered in the comparison between Leibniz and Aristotle – they demonstrate how Leibniz took over, treated or criticised Aristotelian theses. (shrink)