An overview of different versions and applications of Lorenzen’s dialogue game approach to the foundations of logic, here largely restricted to the realm of manyvalued logics, is presented. Among the reviewed concepts and results are Giles’s characterization of Łukasiewicz logic and some of its generalizations to other fuzzy logics, including interval based logics, a parallel version of Lorenzen’s game for intuitionistic logic that is adequate for finite- and infinite-valued Gödel logics, and a truth comparison game for infinite-valued Gödel logic.

We present an interdisciplinary approach to study systematic relations between logical form and attacks between claims in an argumentative framework. We propose to generalize qualitative attack principles by quantitative ones. Specifically, we use coherent conditional probabilities to evaluate the rationality of principles which govern the strength of argumentative attacks. Finally, we present an experiment which explores the psychological plausibility of selected attack principles.

Vagueness is one of the most persistent and challenging topics in the intersection of philosophy and logic. At least five other noteworthy books on vagueness have been written by philosophers since 1991 [2, 6, 11, 12, 15]. A (necessarily incomplete) bibliography that has been compiled for the Arché project Vagueness: its Nature and Logic (2004-2006) of the University of St Andrews lists more than 350 articles and books on vagueness until 2005.1 Many new and interesting contributions have appeared since. The (...) book under review is much more than yet another addition to this prolific discourse. Nicholas Smith manages to tackle two different tasks that are potentially in tension. On the one hand, he provides a comprehensive, systematic and well written account of various approaches to vagueness that have been debated so far. On the other hand, Smith carefully explains and defends his own theory of vagueness, called fuzzy plurivaluationism. Given the complex and almost unsurmountably large amount of relevant literature and the fact that theories of vagueness based on fuzzy logic have almost universally been rejected by philosophers so far this is no simple feat. In the comments below, I will largely follow the structure of book. If along the way I cannot resist to make side remarks or even take issue with some of.. (shrink)

A general class of labeled sequent calculi is investigated, and necessary and sufficient conditions are given for when such a calculus is sound and complete for a finite -valued logic if the labels are interpreted as sets of truth values. Furthermore, it is shown that any finite -valued logic can be given an axiomatization by such a labeled calculus using arbitrary "systems of signs," i.e., of sets of truth values, as labels. The number of labels needed is logarithmic in the (...) number of truth values, and it is shown that this bound is tight. (shrink)

In the 1970s, Robin Giles introduced a game combining Lorenzen-style dialogue rules with a simple scheme for betting on the truth of atomic statements, and showed that the existence of winning strategies for the game corresponds to the validity of formulas in Łukasiewicz logic. In this paper, it is shown that ‘disjunctive strategies’ for Giles’s game, combining ordinary strategies for all instances of the game played on the same formula, may be interpreted as derivations in a corresponding proof system. In (...) particular, such strategies mirror derivations in a hypersequent calculus developed in recent work on the proof theory of Łukasiewicz logic. (shrink)

A uniform construction for sequent calculi for finite-valued first-order logics with distribution quantifiers is exhibited. Completeness, cut-elimination and midsequent theorems are established. As an application, an analog of Herbrand’s theorem for the four-valued knowledge-representation logic of Belnap and Ginsberg is presented. It is indicated how this theorem can be used for reasoning about knowledge bases with incomplete and inconsistent information.

Motivated by aspects of reasoning in theories of physics, Robin Giles defined a characterization of infinite valued Łukasiewicz logic in terms of a game that combines Lorenzen-style dialogue rules for logical connectives with a scheme for betting on results of dispersive experiments for evaluating atomic propositions. We analyze this game and provide conditions on payoff functions that allow us to extract many-valued truth functions from dialogue rules of a quite general form. Besides finite and infinite valued Łukasiewicz logics, also Meyer (...) and Slaney’s Abelian logic and Cancellative Hoop Logic turn out to be characterizable in this manner. (shrink)

The aim of this paper is to emphasize the fact that for all finitely-many-valued logics there is a completely systematic relation between sequent calculi and tableau systems. More importantly, we show that for both of these systems there are al- ways two dual proof sytems (not just only two ways to interpret the calculi). This phenomenon may easily escape one’s attention since in the classical (two-valued) case the two systems coincide. (In two-valued logic the assignment of a truth value and (...) the exclusion of the opposite truth value describe the same situation.). (shrink)

We explore different ways to generalize Hintikka’s classic game theoretic semantics to a many-valued setting, where the unit interval is taken as the set of truth values. In this manner a plethora of characterizations of Łukasiewicz logic arise. Among the described semantic games is Giles’s dialogue and betting game, presented in a manner that makes the relation to Hintikka’s game more transparent. Moreover, we explain a so-called explicit evaluation game and a ‘bargaining game’ variant of it. We also describe a (...) recently introduced backtracking game as well as a game with random choices for Łukasiewicz logic. (shrink)

We present an interdisciplinary approach to argumentation combining logical, probabilistic, and psychological perspectives. We investigate logical attack principles which relate attacks among claims with logical form. For example, we consider the principle that an argument that attacks another argument claiming A triggers the existence of an attack on an argument featuring the stronger claim A ∧ B. We formulate a number of such principles pertaining to conjunctive, disjunctive, negated, and implicational claims. Some of these attack principles seem to be prima (...) facie more plausible than others. To support this intuition, we suggest an interpretation of these principles in terms of coherent conditional probabilities. This interpretation is naturally generalized from qualitative to quantitative principles. Specifically, we use our probabilistic semantics to evaluate the rationality of principles which govern the strength of argumentative attacks. In order to complement our theoretical analysis with an empirical perspective, we present an experiment with students of the TU Vienna ( n = 139) which explores the psychological plausibility of selected attack principles. We also discuss how our qualitative attack principles relate to well-known types of logical argumentation frameworks. Finally, we briefly discuss how our approach relates to the computational argumentation literature. (shrink)

We introduce a game for Gödel logic where the players’ interaction stepwise reduces claims about the relative order of truth degrees of complex formulas to atomic truth comparison claims. Using the concept of disjunctive game states this semantic game is lifted to a provability game, where winning strategies correspond to proofs in a sequents-of-relations calculus.

Cognitive impenetrability (CI) of a large part of visual perception is taken for granted by those of us in the field of computational vision who attempt to recover descriptions of space using geometry and statistics as tools. These tools clearly point out, however, that CI cannot extend to the level of structured descriptions of object surfaces, as Pylyshyn suggests. The reason is that visual space – the description of the world inside our heads – is a nonEuclidean curved space. As (...) a consequence, the only alternative for a vision system is to develop several descriptions of space–time; these are representations of reduced intricacy and capture partial aspects of objective reality. As such, they make sense in the context of a class of tasks/actions/plans/purposes, and thus cannot be cognitively impenetrable. (shrink)

An adequate theory of rights ought to forbid the harming of animals to promote trivial interests of humans, as is often done in the animal-user industries. But what should the rights view say about situations in which harming some animals is necessary to prevent intolerable injustices to other animals? I develop an account of respectful treatment on which, under certain conditions, it’s justified to intentionally harm some individuals to prevent serious harm to others. This can be compatible with recognizing the (...) inherent value of the ones who are harmed. My theory has important implications for contemporary moral issues in nonhuman animal ethics, such as the development of cultured meat and animal research. (shrink)

Value capture occurs when an agent’s values are rich and subtle; they enter a social environment that presents simplified — typically quantified — versions of those values; and those simplified articulations come to dominate their practical reasoning. Examples include becoming motivated by FitBit’s step counts, Twitter Likes and Re-tweets, citation rates, ranked lists of best schools, and Grade Point Averages. We are vulnerable to value capture because of the competitive advantage that such crisp and clear expressions of value have in (...) our private reasoning and our public justification. There is, however, a price. In value capture, we take a central component of our autonomy — our ongoing deliberation over the exact articulation of our values — and we outsource it. And the metrics to which we outsource usually engineered for the interests of some external force, like a large-scale institution’s interest in cross-contextual comprehensibility and quick aggregability. That outsourcing cuts off one of the key benefits to personal deliberation. In value capture, we no longer adjust our values and their articulations in light of own rich experience of the world. Our values should often be carefully tailored to our particular selves or our small-scale communities, but in value capture, we buy our values off the rack. In some cases – like decreasing CO2 emissions – the costs of non-tailored values are outweighed by the benefit of precise collective coordination. In other cases, like in our aesthetic lives, they are not. This suggests that we should want different values suited to different scales. We should want value federalism. Some values are perhaps best pursued at the largest-scale level, others at smaller scales. The problem occurs when we exhibit an excess preference for the largest-scale values – when we consistently let the universal metrics swamp our quieter interests. (shrink)

A construction principle for natural deduction systems for arbitrary, finitely-many-valued first order logics is exhibited. These systems are systematically obtained from sequent calculi, which in turn can be automatically extracted from the truth tables of the logics under consideration. Soundness and cut-free completeness of these sequent calculi translate into soundness, completeness, and normal-form theorems for natural deduction systems.

In The Case for Animal Rights, Tom Regan argues that although all subjects-of-a-life have equal inherent value, there are often differences in the value of lives. According to Regan, lives that have the highest value are lives which have more possible sources of satisfaction. Regan claims that the highest source of satisfaction, which is available to only rational beings, is the satisfaction associated with thinking impartially about moral choices. Since rational beings can bring impartial reasons to bear on decision making, (...) Regan maintains that they have an additional possible source of satisfaction that nonrational beings do not have and, consequently, the lives of rational beings turn out to have greater value.. (shrink)

Анотація. У статті проаналізовані досягнення Соціального Вчительства Католицької Церкви, репрезентовані працями Лева ХІІІ, Пія ХІ, Пія ХІІ, Івана Павла ІІ, що розкривають змістовні характеристики поняття «принцип субсидіарності», його роль і значення в системі християнських цінностей. Принцип субсидіарності робить можливими такі взаємовідносини в соціальному житті, коли спільнота вищого порядку не втручається у внутрішнє життя спільноти нижчого порядку, перебираючи на себе належні тій функції; заради спільного добра, спільного блага вона надає їй у разі потреби підтримку й допомогу, узгоджуючи у такий спосіб її (...) взаємодію з іншими соціальними структурами. Принцип субсидіарності скеровує соціальну практику на утвердження спільного блага в людському співтоваристві. Поширення і застосування принципу субсидіарності протистоїть небезпеці «одержавлення» суспільства та найзагрозливіших проявів колективізму, обмежує абсолютизацію влади, бюрократизацію державних і соціокультурних структур, стає одним із гарантів дотримання прав і свобод громадян своєї країни. (shrink)

In her BBC Reith Lectures on Trust, Onora O’Neill offers a short, but biting, criticism of transparency. People think that trust and transparency go together but in reality, says O'Neill, they are deeply opposed. Transparency forces people to conceal their actual reasons for action and invent different ones for public consumption. Transparency forces deception. I work out the details of her argument and worsen her conclusion. I focus on public transparency – that is, transparency to the public over expert domains. (...) I offer two versions of the criticism. First, the epistemic intrusion argument: The drive to transparency forces experts to explain their reasoning to non-experts. But expert reasons are, by their nature, often inaccessible to non-experts. So the demand for transparency can pressure experts to act only in those ways for which they can offer public justification. Second, the intimate reasons argument: In many cases of practical deliberation, the relevant reasons are intimate to a community and not easily explicable to those who lack a particular shared background. The demand for transparency, then, pressures community members to abandon the special understanding and sensitivity that arises from their particular experiences. Transparency, it turns out, is a form of surveillance. By forcing reasoning into the explicit and public sphere, transparency roots out corruption — but it also inhibits the full application of expert skill, sensitivity, and subtle shared understandings. The difficulty here arises from the basic fact that human knowledge vastly outstrips any individual’s capacities. We all depend on experts, which makes us vulnerable to their biases and corruption. But if we try to wholly secure our trust — if we leash groups of experts to pursuing only the goals and taking only the actions that can be justified to the non-expert public — then we will undermine their expertise. We need both trust and transparency, but they are in essential tension. This is a deep practical dilemma; it admits of no neat resolution, but only painful compromise. (shrink)

Vague language and corresponding models of inference and information processing is an important and challenging topic as witnessed by a number of recent monographs and collections of essays devoted to the topic. This volume collects fifteen papers, the majority of which originated with talks presented at the conference "Logical Models of Reasoning with Vague Information ", September 14-17, 2009, in Čejkovice, that initiated a EUROCORES/LogICCC project with the same title. At least two features set the current volume apart from other (...) texts: first, the interdisciplinary nature of the topic is nicely reflected by the wide range of interests of the authors, who include philosophers, linguists, logicians, as well as mathematicians and computer scientists. Secondly, all the papers are accompanied by comments written by other authors and a few outside experts. These comments and corresponding replies by the authors document the very lively ongoing debate on adequate models of vague language. (shrink)

Recent discussions in the just war literature suggest that soldiers have a duty to assume certain risks in order to protect the lives of all innocent civilians. I challenge this principle of risk by arguing that it is justified neither as a principle that guides the conduct of combat soldiers, nor as a principle that guides commanders in the US military. I demonstrate that the principle of risk fails on the first account because it requires soldiers both to violate their (...) strict duty of obedience and loyalty and to exceed their special obligations to protect their fellow comrades, the state, the state's constituents and other protected civilians. I then illustrate that the principle of risk fails on the second account since it conflicts with the commander's primary obligation to protect and promote the welfare and lives of his or her soldiers. I conclude by arguing that we cannot reasonably expect soldiers and commanders to adhere to the principle of risk until there is a radical, institutional-level transformation of militaristic goals, values, strategies, policies, warrior codes and expectations of service members in the US Armed Forces. (shrink)

Монографія "Функціональність релігії: український контекст".

This classic and controversial book examines the roots of the idea of virtue, diagnoses the reasons for its absence in modern life, and proposes a path for its recovery.

A selection of speeches and essays from the author's second decade as president of Yale University.

Стаття С. Присухіна «Іван Павло ІІ про логіку діалогу між Католицькою Церквою та ісламом» присвячена філософськобогословським напрацюванням Папи Римського Івана Павла ІІ щодо аналізу змістовних характеристик поняття «діалог між католицизмом і ісламом», а також логіки його здійснення в непростому й суперечливому сьогоденні.

The goal of this study was to determine whether it is possible to teach children with serious decoding problems four text comprehension strategies in listening contexts. The subjects were 9-11 year old students from special schools for children with learning disabilities. All the students were very poor at decoding; half of the group were also poor listeners, whereas the other half consisted of normal listeners. The experimental children were trained in strategies of clarifying, questioning, summarising and predicting through a combination (...) of reciprocal teaching and direct instruction. The results indicated significant programme effects on a strategic listening comprehension test. A transfer effect on general listening comprehension and general reading comprehension tests was not found. The poor listeners within the experimental group did not perform better than the normal listeners. (shrink)

Games have a complex, and seemingly paradoxical structure: they are both competitive and cooperative, and the competitive element is required for the cooperative element to work out. They are mechanisms for transforming competition into cooperation. Several contemporary philosophers of sport have located the primary mechanism of conversion in the mental attitudes of the players. I argue that these views cannot capture the phenomenological complexity of game-play, nor the difficulty and moral complexity of achieving cooperation through game-play. In this paper, I (...) present a different account of the relationship between competition and cooperation. My view is a distributed view of the conversion: success depends on a large number of features. First, the players must achieve the right motivational state: playing for the sake of the struggle, rather than to win. Second, successful transformation depends on a large number of extra-mental features, including good game design, and social and institutional features. (shrink)

The current debate over aesthetic testimony typically focuses on cases of doxastic repetition — where, when an agent, on receiving aesthetic testimony that p, acquires the belief that p without qualification. I suggest that we broaden the set of cases under consideration. I consider a number of cases of action from testimony, including reconsidering a disliked album based on testimony, and choosing an artistic educational institution from testimony. But this cannot simply be explained by supposing that testimony is usable for (...) action, but unusable for doxastic repetition. I consider a new asymmetry in the usability aesthetic testimony. Consider the following cases: we seem unwilling to accept somebody hanging a painting in their bedroom based merely on testimony, but entirely willing to accept hanging a painting in a museum based merely on testimony. The switch in intuitive acceptability seems to track, in some complicated way, the line between public life and private life. These new cases weigh against a number of standing theories of aesthetic testimony. I suggest that we look further afield, and that something like a sensibility theory, in the style of John McDowell and David Wiggins, will prove to be the best fit for our intuitions for the usability of aesthetic testimony. I propose the following explanation for the new asymmetry: we are willing to accept testimony about whether a work merits being found beautiful; but we are unwilling to accept testimony about whether something actually is beautiful. (shrink)

Art can be addressed, not just to individuals, but to groups. Art can even be part of how groups think to themselves – how they keep a grip on their values over time. I focus on monuments as a case study. Monuments, I claim, can function as a commitment to a group value, for the sake of long-term action guidance. Art can function here where charters and mission statements cannot, precisely because of art’s powers to capture subtlety and emotion. In (...) particular, art can serve as the vessel for group emotions, by making emotional content sufficiently public so as to be the object of a group commitment. Art enables groups to guide themselves with values too subtle to be codified. (shrink)

De Interpretatione is among Aristotle's most influential and widely read writings; C. W. A. Whitaker presents the first systematic study of this work, and offers a radical new view of its aims, its structure, and its place in Aristotle's system. He shows that De Interpretatione is not a disjointed essay on ill-connected subjects, as traditionally thought, but a highly organized and systematic treatise on logic, argument, and dialectic.

Because factory-farmed meat production inflicts gratuitous suffering upon animals and wreaks havoc on the environment, there are morally compelling reasons to become vegetarian. Yet industrial plant agriculture causes the death of many field animals, and this leads some to question whether consumers ought to get some of their protein from certain kinds of non factory-farmed meat. Donald Bruckner, for instance, boldly argues that the harm principle implies an obligation to collect and consume roadkill and that strict vegetarianism is thus immoral. (...) But this argument works only if the following claims are true: all humans have access to roadkill, roadkill would go to waste if those who happen upon it don’t themselves consume it, it’s impossible to harvest vegetables without killing animals, the animals who are killed in plant production are all-things-considered harmed by crop farming, and the best arguments for vegetarianism all endorse the harm principle. As I will argue in this paper, each claim is deeply problematic. Consequently, in most cases, humans ought to strictly eat plants and save the roadkill for cats. (shrink)

This is a reply to Elisabeth Camp's and Elijah Millgram's probing discussions of "Games and the Art of Agency", in a symposium in Journal of Ethics and Social Philosophy. Millgram argues that games cannot function as a guide to life, because they are too different from life. Games are limited in a special way: in life, we deliberate about what goals we want to take on, but in games, the goals are fixed and given to us. Camp argues that there (...) is nothing particularly special about games, because the fluidity of agency is all over ordinary life too - games are just like ordinary life. I respond to Millgram: we do deliberate about our ends, in games, when we aesthetically reflect on which games to play. And I respond to Camp: games are distinctive in the way they regulate how our reasons flow across the game/life border. To respond to these criticisms, I add some substantial new features to my account of the motivational structure of game-play. (shrink)

C. S. Lewis takes us on a profound journey through both heaven and hell in this engaging allegorical tale. Using his extraordinary descriptive powers, Lewis introduces us to supernatural beings who will change the way we think about good and evil.

The Statesman is Plato's neglected political work, but it is crucial for an understanding of the development of his political thinking. In some respects it continues themes from the Republic, particularly the importance of knowledge as entitlement to rule. But there are also changes: Plato has dropped the ambitious metaphysical synthesis of the Republic, changed his view of the moral psychology of the citizen, and revised his position on the role of law and institutions. In its presentation of the statesman's (...) expertise, the Statesman modifies, as well as defending in original ways, this central theme of the Republic. (shrink)

C. S. Lewis sets out to persuade his audience of the importance and relevance of universal values such as courage and honor in contemporary society.

'Original and provocative . . . engagingly written. (C Fred Alford) counters Levinas's notorious obscurity with a goodly dose of transparency' - John Lechte, Macquarrie University Abstract and evocative, writing in what can only be ...