Gödel's modal ontological argument is the centerpiece of an extensive examination of intensional logic. First, classical type theory is presented semantically, tableau rules for it are introduced, and the Prawitz/Takahashi completeness proof is given. Then modal machinery is added to produce a modified version of Montague/Gallin intensional logic. Finally, various ontological proofs for the existence of God are discussed informally, and the Gödel argument is fully formalized. Parts of the book are mathematical, parts philosophical.

Ever since Saul Kripke and others developed a semantic interpretation for modal logic, 'possible worlds' has been a much debated issue in contemporary metaphysics. To propose the idea of a possible world that differs in some way from our actual world - for example a world where the grass is red or where no people exist - can help us to analyse and understand a wide range of philosophical concepts, such as counterfactuals, properties, modality, and of course, the notions of (...) possibility and necessity. This book examines the ways in which possible worlds have been used as a framework for considering problems in logic and argument analysis. The book begins with a non-technical introduction to the basic ideas of modal logic in terms of Kripke's possible worlds and then moves on to a discussion of 'possible for' and 'possible that'. The central chapters examine questions of meaning, epistemic possibility, temporal logic, metaphysics, and impossibility. Girle also investigates how the idea of a possible world can be put to use in different areas of philosophy, the problems it may raise, and the benefits that can be gained. (shrink)

The new edition of this widely used and respected textbook includes three new chapters on conditional logic. Other chapters have been revised and updated, making the second edition a fully comprehensive introduction to modal logics and their application. Unlike most modal logic textbooks, which are both forbidding mathematically and short on philosophical discussion, Modal Logics and Philosophy focuses on showing how useful modal logic can be as a tool for formal philosophical analysis. In Part 1, the reader is introduced to (...) some standard systems of modal logic and provided with a series of exercises that encourage proficiency in manipulating these logics. Girle emphasizes possible world semantics for modal logics and its formal method, Jeffrey-style truth-trees, in which standard truth-trees are extended in a simple and transparent way to take possible worlds into account. Part 2 explores the applications of modal logic to philosophical issues such as truth, time, processes, knowledge and belief, and obligation and permission. (shrink)

This textbook places emphasis on showing how useful a tool modal logic can be for formal philosophy, metaphysics, temporal reasoning, epistemics, the analysis of action and processes and ethical reasoning. Moving beyond propositional logic and predicate logic, modal logic gives the power to articulates and explore with precision philosophical arguments concerning possibility and necessity that are essential concepts in thought. This textbook is intended as an introductory study of modal logics with philosophy. In part 1 the reader is introduced to (...) some standard systems of modal logic, emphasis being on world semantics for modal logics. Part 2 explores modal logic applications to profound philosophical issues. (shrink)

The new edition of this widely used and respected textbook includes three new chapters on conditional logic. Other chapters have been revised and updated, making the second edition a fully comprehensive introduction to modal logics and their application. Unlike most modal logic textbooks, which are both forbidding mathematically and short on philosophical discussion, Modal Logics and Philosophy focuses on showing how useful modal logic can be as a tool for formal philosophical analysis. In Part 1, the reader is introduced to (...) some standard systems of modal logic and provided with a series of exercises that encourage proficiency in manipulating these logics. Girle emphasizes possible world semantics for modal logics and its formal method, Jeffrey-style truth-trees, in which standard truth-trees are extended in a simple and transparent way to take possible worlds into account. Part 2 explores the applications of modal logic to philosophical issues such as truth, time, processes, knowledge and belief, and obligation and permission. (shrink)

In this paper I argue that, given three popular modern doctrines which are combined in some accounts of modality, the outcome is equivalent to a suitably demythologised metaphysics of Parmenides. Prior has some anticipatory comment on the possible outcomes. © 2011 Elsevier B.V., All rights reserved.

In this paper we compare central elements of Dialogue Logic and Belief Revision theory. Dialogue Logic of the Hamblin/Mackenzie style, or Formal Dialectic, contains three main features. First, there is a rule governed interaction between dialogue participants—the minimal case being two participants. Second, each participant has a commitment store which changes as the dialogue progresses. Third, the changes in the commitment store are governed by rules for additions and withdrawals of material. Withdrawal of material is one major source of difficulty (...) in proposing rules for commitment store change. The classic Belief Revision theory is the AGM theory. AGM theory is a theory about ideal rational believers who change their sets of beliefs by either expansion or contraction. Contraction is a major source of difficulty in belief revision theory. We claim that the commitment stores of dialogue logic include, in a sense, the belief sets of belief revision theory. Further, withdrawal and contraction are essentially the same process. We consider various kinds of withdrawal and contraction, and show how approaches to these processes illuminate certain of the formal fallacies. (shrink)

There are several formal systems for persuasive dialogue. Dialogue systems are multi-Agent systems, and this contrasts with the general lack of any agency in standard logics other than in the case of epistemic and deontic logics. Dialogue systems have been called logics. A logic usually has a semantics and a proof system, and questions of soundness and completeness arise. Any dialogue conducted according to the rules of a dialogue logic is a complex process. Dynamic Logic is a logic of processes, (...) with a possible world semantics. This paper is a preliminary exploration of transforming the dialogues of dialogue logic into complex Dynamic Logic processes with emphasis on semantic models. The transformation gives rise to many questions, three of which are discussed. Dialogue logic includes commitment sets which behave in a way similar to belief sets and undergo changes during any dialogue. There are issues as to the relationship between belief and commitment, and whether the logics of belief change apply to commitment stores. There is also the issue of the logical nature of the evaluation of dialogues as legal or illegal. (shrink)

INTRODUCTION TO LOGIC is a combined text and workbook for students beginning their study of logic. The workbook style allows students to proceed at their own pace, checking their progress in the end-of-chapter exercises. The text covers propositional logic and predicate logic with identity, the focus being on arguments. The methods of proof are truth-tables and truth-trees in the style of Jeffrey. This text is suitable for students of philosophy, computer science, mathematics and science in general.

Jan Łukasiewicz’s analysis of Aristotle’s syllogism drew attention to the nature of syllogisms as conditionals rather than premise-conclusion arguments. His further idea that syllogisms should be understood as theorems of an axiom system seems a step too far for many logicians. But there is evidence to suggest that Aristotle’s syllogism was to regularise some of the steps made in ‘dialogue games.’ This way of seeing the syllogism is explored in the framework of modern formal dialogue systems. A modern formal syllogistic (...) game, DLSyll, is set out and analysed in use. (shrink)

It has been argued that consciousness might be what differentiates human from machine mentality. What then is consciousness? We discuss consciousness, particularly perception accounts of consciousness. It is argued that perception and consciousness are distinct. Armstrong's account of consciousness is rejected. It is proposed that perception is a necessary but not sufficient condition for consciousness, and that there is a distinction to be drawn between consciousness and self-consciousness. Consciousness is tightly linked to attention and to certain sorts of knowledge. Implications (...) for machine consciousness and machine attention are discussed. (shrink)

L'objet chez Duchamp n'est ni la chose ni la matière : c'est un concept artistique. L'objet duchampien fait disparaître la signification habituelle d'une chose quotidienne sous un nouveau titre. Sur la base de cette définition de l'objet duchampien, nous développons trois hypothèses : l'objet ou le mensonge pictural, ce qui n'est pas l'objet ou la chose elle-même, et l'idée de l'objet duchampien ou la chose indirecte. À travers l'esthétique et la méthode de Duchamp, nous en venons à conclure que l'objet (...) duchampien est mensonge pictural et chose indirecte. Car Duchamp profite du mensonge, au sens de Platon, qui ne se réalise que dans l'art, et il présente méthodiquement la chose quotidienne comme chose indirecte. (shrink)

While previous work has highlighted the possible impacts of undertaking emotionally challenging research, it is only recently, particularly within the UK with the 2028 Research Excellence Framework focus on research culture, that this subject is starting to gain senior leadership attention. Funded by the UK Research and Innovation, Researcher England, Enhancing Research Culture fund. We undertook an in-depth study involving researchers across topics and disciplines in the humanities and social science, with the objectives of establishing: the impacts of studying emotionally (...) challenging topics on researchers, what they currently found helpful in preventing and/or coping with these impacts, and what additional support they wanted. In this paper we report on findings related to the latter two objectives to provide insight into how future research projects could be ethically designed to minimize distress, secondary and vicarious trauma in researchers. We then use these findings to formulate an innovative strategic institutional response to researcher wellbeing and emotionally challenging studies that can be implemented in three stages: Bronze, which is focused on awareness raising and the development of policies and guidance that are built into ethical procedures; Silver, involving the establishment of training, clear referral pathways, and (funded) Researcher Wellbeing Plans - including regular academic supervision, team working, and extra time in workloads to undertake wellbeing interventions - built into the design of projects; and Gold, a wholistic institutional response where, in addition to the above, policies, processes, practices and culture are proactively attentive to the prevention of and provision for distress relating to emotionally challenging research. (shrink)