v. 1. On the twelfth century theories of fallacy.--v. 2. The origin and early development of the theory of supposition.

v. 1. General introduction, the works on logic -- v. 2. The metaphysics, semantics in Aristotle's strategy of argument.

Paperback. This volume is a new interpretation of Plato's earlier and later Theory of Ideas, starting from a detailed analysis of the dialogue, The Sophist.The way in which Plato announces his novel Metaphysics has been puzzling scholars for a long time. Did Plato really introduce Change into the Transcendent World and thus abandon his Theory of Unchangeable Forms?Many of Plato's commentators have claimed that the use of modern techniques of logico-semantical analysis can be a valuable aid in unravelling this problem, (...) as well as other difficulties Plato raised and attempted to solve. In this commentary, Plato's own logico-semantical approach to metaphysical problems is followed. (shrink)

Building on the recent scholarship of Bonnie Kent, Christian Trottmann, and especially L.M. de Rijk, this volume gathers together studies by other specialists on Odonis, covering his ideas in economics, logic, metaphysics, ethics, natural ...

The strong connection between the two and its development into the Middle Ages form a major subject of this volume.Other themes featuring in this book are Plato ...

Professor de Rijk's interest here is in the views on reality put forward by the medieval thinkers from Boethius to William of Ockham, but especially in the 12th-14th centuries, the period from Abelard onwards.Theology was naturally a key influence, but sematic theories - the philosophical theories on how terms signify, or how a name has its meaning and how this is affected by its context - were fundamental as the starting point of ontological speculation. The categories formulated in order (...) to differentiate various types of context and their impact on the semantics of the verb esse, 'to be', and its related forms. De Rijk's aim is to understand how these medieval thinkers interpreted reality according to their own semantic views, and to see how their own particular concerns - for instance William of Ockham's application of the 'principle of parsimony' to ontology - shaped the nature of their thought. (shrink)

Wijsgerige bezinning op de rol en betekenis van religie in het debat over normen en waarden.

Bundel inleidende colleges op pre-kandidaatsniveau.

L. M. de Rijk, born at Hilversum (Nederland) November, 6 1924, is Professor Emeritus of Ancient and Medieval Philosophy at the University of Leiden, and Honorary Professor at the University of Maastricht. A complete bibliography of his writings up to 1999 is available in: Maria Kardaun and Joke Spruyt (eds.) - The winged chariot. Collected essays on Plato and Platonism in honour of L. M. de Rijk - Leiden, Brill, 2000. pp. XV-XXVI. I made some corrections, updated the (...) bibliography and omitted the publications in Dutch. (shrink)

This modern, advanced textbook reviews modal logic, a field which caught the attention of computer scientists in the late 1970's.

We consider some modal languages with a modal operator $D$ whose semantics is based on the relation of inequality. Basic logical properties such as definability, expressive power and completeness are studied. Also, some connections with a number of other recent proposals to extend the standard modal language are pointed at.

In this paper back-and-forth structures are applied to the semantics of natural language. Back-and-forth structures consist of an event structure and an interval structure communicating via a relational link; transitions in the one structure correspond to transitions in the other. Such entities enable us to view temporal constructions (such as tense, aspect, and temporal connectives) as methods of moving systematically between information sources. We illustrate this with a treatment of the English present perfect, and progressive aspect, that draws on ideas (...) developed in Moens & Steedman (1988), and discuss the role of rich ontologies in formal semantics. (shrink)

For an arbitrary similarity type of Boolean Algebras with Operators we define a class ofSahlqvist identities. Sahlqvist identities have two important properties. First, a Sahlqvist identity is valid in a complex algebra if and only if the underlying relational atom structure satisfies a first-order condition which can be effectively read off from the syntactic form of the identity. Second, and as a consequence of the first property, Sahlqvist identities arecanonical, that is, their validity is preserved under taking canonical embedding algebras. (...) Taken together, these properties imply that results about a Sahlqvist variety V van be obtained by reasoning in the elementary class of canonical structures of algebras in V.We give an example of this strategy in the variety of Cylindric Algebras: we show that an important identity calledHenkin's equation is equivalent to a simpler identity that uses only one variable. We give a conceptually simple proof by showing that the first-order correspondents of these two equations are equivalent over the class of cylindric atom structures. (shrink)

In many logics dealing with information one needs to make statements not only about cognitive states, but also about transitions between them. In this paper we analyze a dynamic modal logic that has been designed with this purpose in mind. On top of an abstract information ordering on states it has instructions to move forward or backward along this ordering, to states where a certain assertion holds or fails, while it also allows combinations of such instructions by means of operations (...) from relation algebra. In addition, the logic has devices for expressing whether in a given state a certain instruction can be carried out, and whether that state can be arrived at by carrying out a certain instruction.This paper deals mainly with technical aspects of our dynamic modal logic. It gives an exact description of the expressive power of this language; it also contains results on decidability for the language with arbitrary structures and for the special case with a restricted class of admissible structures. In addition, a complete axiomatization is given. The paper concludes with a remark about the modal algebras appropriate for our dynamic modal logic, and some questions for further work. (shrink)

We introduce a notion of bisimulation for graded modal logic. Using this notion, the model theory of graded modal logic can be developed in a uniform manner. We illustrate this by establishing the finite model property and proving invariance and definability results.

In many logics dealing with information one needs to make statements not only about cognitive states, but also about transitions between them. In this paper we analyze a dynamic modal logic that has been designed with this purpose in mind. On top of an abstract information ordering on states it has instructions to move forward or backward along this ordering, to states where a certain assertion holds or fails, while it also allows combinations of such instructions by means of operations (...) from relation algebra. In addition, the logic has devices for expressing whether in a given state a certain instruction can be carried out, and whether that state can be arrived at by carrying out a certain instruction. This paper deals mainly with technical aspects of our dynamic modal logic. It gives an exact description of the expressive power of this language; it also contains results on decidability for the language with 'arbitrary' structures and for the special case with a restricted class of admissible structures. In addition, a complete axiomatization is given. The paper concludes with a remark about the modal algebras appropriate for our dynamic modal logic, and some questions for further work. The paper only contains some sketchy examples showing how the logic can be used to capture situations of dynamic interest, far more detailed applications are given in a companion to this paper (De Rijke [33]). (shrink)

Peirce algebras combine sets, relations and various operations linking the two in a unifying setting. This paper offers a modal perspective on Peirce algebras. Using modal logic a characterization of the full Peirce algebras is given, as well as a finite axiomatization of their equational theory that uses so-called unorthodox derivation rules. In addition, the expressive power of Peirce algebras is analyzed through their connection with first-order logic, and the fragment of first-order logic corresponding to Peirce algebras is described in (...) terms of bisimulations. (shrink)

This article argues in favour of voluntary active euthanasia in human beings on the grounds that we (society in general) perform euthanasia on valued companion animals when their suffering is considered great. I argue that suffering is a morally relevant criterion that should be considered in all cases (human and animal) of euthanasia. I further argue that human beings possess autonomy, a morally relevant difference to companion animals, that allows them to reason about their futures in a way that animals (...) cannot, which gives us more reason to grant euthanasia, if requested autonomously by terminally ill patients who are experiencing extreme suffering. I consider objections around the sanctity of human life and sufficient palliation. I argue that neither of these objections give sufficient reason to deny competent human beings euthanasia if autonomously requested. (shrink)

IT is well known that the art of logic (logica or diale(c)tica) knew a remarkable flourishing period during the twelfth century. In the first half of the century its main centres in Paris were: the School of Notre DameI, of St. Victor2, of the Petit Pont3 and of Mont Ste Geneviève4. The present paper aims to offer some new evidence from the manuscripts on the teaching of logic as given in the School of Mont Ste.