Preference is a basic notion in human behaviour, underlying such varied phenomena as individual rationality in the philosophy of action and game theory, obligations in deontic logic (we should aim for the best of all possible worlds), or collective decisions in social choice theory. Also, in a more abstract sense, preference orderings are used in conditional logic or non-monotonic reasoning as a way of arranging worlds into more or less plausible ones. The field of preference logic (cf. Hansson [10]) studies (...) formal systems that can express and analyze notions of preference between various sorts of entities: worlds, actions, or propositions. The art is of course to design a language that combines perspicuity and low complexity with reasonable expressive power. In this paper, we take a particularly simple approach. As preferences are binary relations between worlds, they naturally support standard unary modalities. In particular, our key modality ♦ϕ will just say that is ϕ true in some world which is at least as good as the current one. Of course, this notion can also be indexed to separate agents. The essence of this language is already in [4], but our semantics is more general, and so are our applications and later language extensions. Our modal language can express a variety of preference notions between propositions. Moreover, as already suggested in [9], it can “deconstruct” standard conditionals, providing an embedding of conditional logic into more standard modal logics. Next, we take the language to the analysis of games, where some sort of preference logic is evidently needed ([23] has a binary modal analysis different from ours). We show how a qualitative unary preference modality suffices for defining Nash Equilibrium in strategic games, and also the Backward Induction solution for finite extensive games. Finally, from a technical perspective, our treatment adds a new twist. Each application considered in this paper suggests the need for some additional access to worlds before the preference modality can unfold its true power.. (shrink)

The most widely used attractive logical account of knowledge uses standard epistemic models, i.e., graphs whose edges are indistinguishability relations for agents. In this paper, we discuss more general topological models for a multi-agent epistemic language, whose main uses so far have been in reasoning about space. We show that this more geometrical perspective affords greater powers of distinction in the study of common knowledge, defining new collective agents, and merging information for groups of agents.

1 Logic in philosophy The century that was Logic has played an important role in modern philosophy, especially, in alliances with philosophical schools such as the Vienna Circle, neopositivism, or formal language variants of analytical philosophy. The original impact was via the work of Frege, Russell, and other pioneers, backed up by the prestige of research into the foundations of mathematics, which was fast bringing to light those amazing insights that still impress us to-day. The Golden Age of the 1930s (...) deeply affected philosophy, and heartened the minority of philosophers with a formalanalytical bent. As Brand Blanshard writes in Reason and Analysis (1964) – I quote from memory here, to avoid the usual disappointment when re-reading an original text. (shrink)

Transition systems can be viewed either as process diagrams or as Kripke structures. The rst perspective is that of process theory, the second that of modal logic. This paper shows how various formalisms of modal logic can be brought to bear on processes. Notions of bisimulation can not only be motivated by operations on transition systems, but they can also be suggested by investigations of modal formalisms. To show that the equational view of processes from process algebra is closely related (...) to modal logic, we consider various ways of looking at the relation between the calculus of basic process algebra and propositional dynamic logic. More concretely, the paper contains preservation results for various bisimulation notions, a result on the expressive power of propositional dynamic logic, and a de nition of bisimulation which is the proper notion of invariance for concurrent propositional dynamic logic. (shrink)

Understanding human behaviour involves "why"'s as well as "how"'s. Rational people have good reasons for acting, but it can be hard to find out what these were and how they worked. In this Note, we discuss a few ways in which actions, preferences, and expectations are intermingled. This mixture is especially clear with the well-known solution procedure for extensive games called 'Backward Induction'. In particular, we discuss three scenarios for analyzing behaviour in a game. One can rationalize given moves as (...) revealing agents' preferences, one can also rationalize them as revealing agents' beliefs about others, but one can also change a predicted pattern of behaviour by making promises. All three scenarios transform given games to new ones, and we prove some results about their scope. A more general view of relevant game transformations would involve dynamic and epistemic game logics. Finally, our analysis describes and disentangles matters: but it will not tell you what to do! (shrink)

Met als uitgangspunt de theorie en wijsbegeerte van het wettenrecht wordt een inzicht gegeven in de ontwikkeling van recht en staat in de 20e eeuw.

Current dynamic epistemic logics often become cumbersome and opaque when common knowledge is added for groups of agents. Still, postconditions regarding common knowledge express the essence of what communication achieves. We present some methods that yield so-called reduction axioms for common knowledge. We investigate the expressive power of public announcement logic with relativized common knowledge, and present reduction axioms that give a detailed account of the dynamics of common knowledge in some major communication types.

Natural languages are vehicles of information, arguably the most important, certainly the most ubiquitous that humans possess. Our everyday interactions with the world, with each other and with ourselves depend on them. And even where in the specialised contexts of science we use dedicated formalisms to convey information, their use is embedded in natural language. This omnipresence of natural language is due in large part to its flexibility, which is almost always a virtue, sometimes a vice. Natural languages are able (...) to carry information in a wide variety of ways, about a seemingly unlimited range of topics, which makes them both efficient and versatile, and hence useful in almost every circumstance. But sometimes, when pinpoint precision is what counts, this versatility can get in the.. (shrink)

Keuze van artikelen uit het werk van de Vlaamse filosoof over wetenschap, milieu, en medische en biologische ethiek.

The interface of logic and philosophy is diverse, and has always been so. Understanding the interplay raises issues on which some philosophers have strong a priori views. My own preference as a working logician is to proceed by actual history of ideas, something still largely to be written for modern logic. I shall present a few lines connecting logic and philosophy around the theme of implication and consequence, and show how rich the agenda is as it keeps evolving with contributions (...) from many disciplines. This is a light survey paper, but I supply references for readers who want to see more of the nitty-gritty details. (shrink)

Over the past decades, logicians interested in rational agency and intelligent interaction studied major components of these phenomena, such as knowledge, belief, and preference. In recent years, standard ‘static’ logics describing information states of agents have been generalized to dynamic logics describing actions and events that produce information, revise beliefs, or change preferences, as explicit parts of the logical system. Van Ditmarsch, van der Hoek & Kooi 2007, Baltag, van Ditmarsch & Moss 2008, van Benthem, to appear A, are up-to-date (...) accounts of this dynamic trend (the present paper follows Chapter 9 of the latter book). But in reality, concrete rational agency contains all these dynamic processes entangled. A concrete setting for this entanglement are games – and this paper is a survey of their interfaces with logic, both static and dynamic. Games are intriguing also since their analysis brings together two major streams, or tribal communities: ‘hard’ mathematical logics of computation, and ‘soft’ philosophical logics of propositional attitudes. Of course, this hard/soft distinction is spurious, and there is no natural border line between the two sources: it is their congenial mixture that makes current theories of agency so lively. (shrink)

Many cognitive activities are irreducibly social, involving interaction between several different agents. We look at some examples of this in linguistic communication and games, and show how logical methods provide exact models for the relevant information flow and world change. Finally, we discuss possible connections in this arena between logico-computational approaches and experimental cognitive science.

Proof, Computation and Agency: Logic at the Crossroads provides an overview of modern logic and its relationship with other disciplines. As a highlight, several articles pursue an inspiring paradigm called 'social software', which studies patterns of social interaction using techniques from logic and computer science. The book also demonstrates how logic can join forces with game theory and social choice theory. A second main line is the logic-language-cognition connection, where the articles collected here bring several fresh perspectives. Finally, the book (...) takes up Indian logic and its connections with epistemology and the philosophy of science, showing how these topics run naturally into each other. (shrink)

This monograph deals with the aboutness of language.

Retornando al modelo dialógico del discurso racional de la antigüedad, describimos a la lógica como el estudio del flujo general de la información: inferencia, observación y comunicación. Mostramos cómo esta perspectiva aúna ideas de la lógica estándar, la filosofía, la lingüística, la informática y la teoría de juegos.

This collection of papers from the workshop serves as the initial volume in the new series Texts in Logics and Games—touching on research in logic, mathematics, computer science, and game theory. “A wonderful demonstration of ...

Paperback. This volume finds its origin in a colloquium on Logic and Argumentation, held in June 1994 in Amsterdam and sponsored by the Royal Netherlands Academy of Arts and Sciences. The papers included have been selected for the role they can play in illuminating current thinking about the various kinds of relations between logic and argumentation.Aiming to provide some background to the academic endeavour of exploring the connections between logic and argumentation this volume offers the reader some representative specimina of (...) current thinking about this subject. (shrink)

This article discusses the meanings of “creativity”—tvorchestvo—as we encounter it in Georges Florovsky’s thought, first and foremost in his magnum opus Ways of Russian Theology (1937). Tvorchestvo had by this time become a key concept in Russian pre-revolutionary and later émigré thought. It is associated above all with Nikolai Berdyaev’s philosophy, but it also plays an important role in Sergei Bulgakov’s philosophy of economy. In both cases, it stands for the human response to divine creation. Moreover, and somewhat less famously, (...) it was also an epistemological concept in the religious idealism of Vladimir Solovyov as well as in Russian neo-Kantianism (Fyodor Stepun), where it stood for the active, synthetic faculty of our minds. Florovsky, meanwhile, used it as a description of how we should relate to the patristic heritage, but also to history more generally: Our attitude should be “creative,” active, as well as both backward- and forward-looking. This “return to the Fathers” was a central component of Florovsky’s neopatristic program, but, interestingly, in order to conceptualize this return, Florovsky took over a concept from traditions that his own approach otherwise firmly criticized. By analyzing Florovsky’s use of tvorchestvo, this article addresses the broader question as to the differences and parallels between the neopatristic movement and the legacy of the Russian Renaissance (Silver Age). (shrink)

Evert van der Zweerde’s book is the most recent result of the author’s long-time study of Russian philosophy and Russian philosophical culture. The latter concept has been one of Zweerde’s main con...

In the post-Soviet context, various cyclical models of recurrent Russian “Times of Troubles” have become increasingly popular. This perspective emerged first in Soviet dissident circles, who used it as a means to expose as mistaken the Soviet belief in continual historical progress on Russian soil. In post-Soviet Russia this critical approach has been continued by members of the “Akhezier circle,” the economist Egor Gaidar, and others. Meanwhile it was given an affirmative, conservative reinterpretation by Aleksandr Panarin, according to whom Russia (...) has always managed to overcome its phases of devastating Westernization and state collapse. This idea of Russian history has become influential; even Vladimir Putin has talked about Russia as a strong state able to survive various “Times of Troubles” from the early seventeenth century to the early post-Soviet period. It also figures prominently among members of the neoconservative Izborsk Club. This article analyzes different conceptions of Russian history as cyclical and their prominent place in the prevailing civilizational discourse of post-Soviet Russia. By means of postcolonial perspectives, this discourse is seen on the one hand as an attempt to question and reject Western hegemony, attempts that on the other hand nevertheless seem unable to liberate themselves from a normative dependence on the West. (shrink)

This book is a philosophical enquiry into the educational consequences of Spinoza’s political theory. Spinoza’s political theory is of particular interest for educational thought as it brings together the normative aims of his ethical theory with his realistic depiction of human psychology and the ramifications of this for successful political governance. As such, the book aims to introduce the reader to Spinoza’s original vision of civic education, as a project that ultimately aims at the ethical flourishing of individuals, while being (...) carefully tailored and adjusted to the natural limitations of human reason. This author-meets-critics includes scholars in philosophy, education and Spinoza studies. (shrink)