The present note revisits the joint work of Leonard Goddard and Richard Routley on significance logics with the aim of shedding new light on their understanding by studying them under the lens of recent semantic developments, such as the plurivalent semantics developed by Graham Priest. These semantics allow sentences to receive one, more than one, or no truth-value at all from a given carrier set. Since nonsignificant sentences are taken to be neither true nor false, i.e. truth-value gaps, (...) in this essay we show that with the aid of plurivalent semantics it is possible to straightforwardly instantiate Goddard and Routley’s understanding of how the connectives should work within significance logics. (shrink)

Informal logic is a new sub-discipline of philosophy, roughly definable as the philosophy of argument. Contributors have challenged the traditional concept of an argument as a premiss-conclusion complex, in favour of speech-act, functional and dialogical conceptions; they have identified as additional components warrants, modal qualifiers, rebuttals, and a dialectical tier. They have objected that "soundness" is neither necessary nor sufficient for a good argument. Alternative proposals include acceptability, relevance and sufficiency of the premisses; conformity to a valid argument schema; conformity (...) to rules for discussion aimed at rational resolution of a dispute. Informal logic is a significant part of philosophy. (shrink)

Assertion plays a crucial dual role in Frege's conception of logic, a formal and a transcendental one. A recurrent complaint is that Frege's inclusion of the judgement-stroke in the Begriffsschrift is either in tension with his anti-psychologism or wholly superfluous. Assertion, the objection goes, is at best of merely psychological significance. In this paper, I defend Frege against the objection by giving reasons for recognising the central logical significance of assertion in both its formal and its transcendental role.

Wolff's German Logic 1713 was a text book for Philosophy Students for many years.

Frege's invention of the predicate calculus has been the most influential event in the history of modern logic. The calculus’ place in logic is so central that many philosophers think, in fact, of it when they think of logic. This book challenges the position in contemporary logic and philosophy of language of the predicate calculus claiming that it is based on mistaken assumptions. Ben-Yami shows that the predicate calculus is different from natural language in its fundamental semantic charac.

W. V. Quine was one of the most influential figures of twentieth-century American analytic philosophy. Although he wrote predominantly in English, in Brazil in 1942 he gave a series of lectures on logic and its philosophy in Portuguese, subsequently published as the book O Sentido da Nova Lógica. The book has never before been fully translated into English, and this volume is the first to make its content accessible to Anglophone philosophers. Quine would go on to develop revolutionary ideas about (...) semantic holism and ontology, and this book provides a snapshot of his views on logic and language at a pivotal stage of his intellectual development. The volume also includes an essay on logic which Quine also published in Portuguese, together with an extensive historical-philosophical essay by Frederique Janssen-Lauret. The valuable and previously neglected works first translated in this volume will be essential for scholars of twentieth-century philosophy. (shrink)

In spite of the fact that the Neyman-Pearson theory of testing is the official theory of statistical testing, most research publications in the social sciences use a pattern of inductive reasoning that is characteristic of Fisherian tests of significance. The exact structure and rationale of this pattern of reasoning is widely misunderstood. The goal of the paper is to describe precisely the pattern and its rationale, and to show that while it is far more cogent than Fisher's critics have (...) realized, it does not logically sustain the inferences it sanctions. (shrink)

Among Kant's innovations in the understanding of logic (‘general logic’) were his claims that logic had no content of its own, but was the form of the thought of any possible content, and that the unit of meaning, the truth-bearer, judgement, was essentially apperceptive. Judging was implicitly the consciousness of judging. This was for Kant a logical truth. This article traces the influence of the latter claim on Fichte, and, for most of the discussion, on Hegel. The aim is to (...) understand the relations among self-consciousness, reason and freedom in the idealist tradition. (shrink)

The logic of intentional verbs and constructions has been intensively studied over the last twenty years in different logical fields : pure logic, philosophy of logic, logic for AI and logic computer science. There is little interaction among these scientific communities. In this paper I shall bring together the more significant results which have been obtained and offer an up to date status quaestionis. I will reduce logical technicalities to a minimum. and lay emphasis on what is philosophically and ethically (...) significant in the recent formalizations of intentional verb and adverbs. (shrink)

In this paper I will investigate the possibility of completing a Positivist style account of demarcation. One reason for pursuing this project is that standard criticisms of Positivism do not have the bite against the demarcation project that they are often assumed to have. To argue this will be the burden of the first part of this paper. The other reason is that new research in logic has provided machinery not available to the Positivists; machinery that shows promise for solving (...) some of the technical problems faced by Positivists' account of demarcation. To argue this will be the burden of the second part of this paper. (shrink)

W. V. Quine was one of the most influential figures of twentieth-century American analytic philosophy. Although he wrote predominantly in English, in Brazil in 1942 he gave a series of lectures on logic and its philosophy in Portuguese, subsequently published as the book O Sentido da Nova Lógica. The book has never before been fully translated into English, and this volume is the first to make its content accessible to Anglophone philosophers. Quine would go on to develop revolutionary ideas about (...) semantic holism and ontology, and this book provides a snapshot of his views on logic and language at a pivotal stage of his intellectual development. The volume also includes an essay on logic which Quine also published in Portuguese, together with an extensive historical-philosophical essay by Frederique Janssen-Lauret. The valuable and previously neglected works first translated in this volume will be essential for scholars of twentieth-century philosophy. (shrink)

This article offers a detailed analysis of Ilyenkov’s conception of the relationship between the logical and the historical. It posits that Ilyenkov, by overcoming the theoretical impasses of mainstream Soviet Marxism, was the first thinker to recognize the centrality of this relationship in dialectics. Through a brief overview of the official conception of Diamat, I explain that the latter broadly understood the relation of the logical and the historical in a rather superficial way. I then argue that Ilyenkov’s approach to (...) dialectics as the ascent from the abstract to the concrete, combined with his research orientation towards the method of Marx’s Capital and his reevaluation of Hegel’s philosophy led him to a much deeper understanding of the inner unity of the method of ascent from the abstract to the concrete and the relation of the logical and the historical. In reconstructing Ilyenkov’s analysis on this matter, I explain how the unfolding of the categories throughout the ascent from the abstract to the concrete is inextricably intertwined with the relation of the logical and the historical. Therefore, the article concludes by arguing that Ilyenkov’s analysis marks a significant advance in the understanding of dialectics in the history of Marxism, and a core aspect of this deeper understanding is his systematic approach to the relationship of the logical and the historical. (shrink)

In "Backward causation and the Stalnaker-Lewis approach to counterfactuals," Analysis 62 (2002): 191–97, Michael Tooley argues that if a certain kind of backward causation is possible, then a Stalnaker-Lewis style comparative world similarity account of the truth conditions of counterfactuals cannot be sound. Tooley’s target is one particular type of semantics, but, as I show, the significance of Tooley’s example goes well beyond its consequences for any one semantics for the conditional.

Let us assume that you are entrusted by UNESCO with an important task. You are asked to devise a universal logical language, a Begriffsschrift in Frege's sense, which is to serve the purposes of science, business and everyday life. What requirements should such a “conceptual notation” satisfy? There are undoubtedly many relevant desiderata, but here I am focusing on one unmistakable one. In order to be a viable lingua universalis, your language must in any case be capable of representing any (...) possible configuration of dependence and independence between different variables. For if such a configuration is possible in principle, there is no guarantee that it might not one day show up among the natural, human or social phenomena we have to study.But how are dependencies and independencies between variables expressed in our familiar logical notation? Every logician worth his or her truth-table knows the answer. Dependencies between two variables are expressed by dependencies between the quantifiers to which they are bound. For instance, inthe variable y depends on x, while inz depends on x but not on y, while u depends on both x and y.But how is the dependence of a quantifier on another one expressed in familiar logical languages? Obviously by occurring in its scope, indicated by the pair of parentheses following it. But the nesting of scopes is a transitive and antisymmetrical relation which allows branching only in one direction. Hence other kinds of structures of dependence and independence between variables are not representable in the received logical notation. Such previously inexpressible structures form the subject matter of what has been referred to as independence-friendly logic. (shrink)

: This essay presents aspects of the philosophy of nature of Nishida Kitarō (1870–1945) (Kyoto School) and its relation to the physics of his day. Which aspects of Einstein’s Theory of Relativity are treated in Nishida’s Logic of Field? Through exact explanations of the fundamental differences between physics and philosophy this essay aims to clarify the construction of logic in philosophy and physics while considering interdisciplinary aspects.

In 1942, before his duties began in the USA Navy, W.V. Quine lectured at the Free School of Sociology and Politics of São Paulo. He wrote up the lectures in Por.

In this short piece, I argue that Chimakonam’s Ezumezu logic bears methodological significance for African scholarship as a whole. If method rests on logic, and method accounts for the distinction of one knowledge output from another, then the formulation of a system of logic which can creditably be described as African, even if simply in cultural inspiration, would provide for methodological liberation of African scholarship trapped in western knowledge hegemony since colonial times. First, I discuss in simple terms the (...) theory of Ezumezu logic before showing its methodological significance. Keywords: Ezumezu, Logic, Chimakonam, African philosophy, Method. (shrink)

Brief note explaining the content, importance, and historical context of my joint translation of Quine's The Significance of the New Logic with my single-authored historical-philosophical essay 'Willard Van Orman Quine's Philosophical Development in the 1930s and 1940s'.

This edited collection provides the first comprehensive volume on A. J. Ayer’s 1936 masterpiece, Language, Truth and Logic. With eleven original chapters the volume reconsiders the historical and philosophical significance of Ayer’s work, examining its place in the history of analytic philosophy and its subsequent legacy. Making use of pioneering research in logical empiricism, the contributors explore a wide variety of topics, from ethics, values and religion, to truth, epistemology and philosophy of language. Among the questions discussed are: How (...) did Ayer preserve or distort the views and conceptions of logical empiricists? How are Ayer's arguments different from the ones he aimed at reconstructing? And which aspects of the book were responsible for its immense impact? The volume expertly places Language, Truth and Logic in the intellectual and socio-cultural history of twentieth-century philosophical thought, providing both introductory and contextual chapters, as well as specific explorations of a variety of topics covering the main themes of the book. Providing important insights of both historical and contemporary significance, this collection is an essential resource for scholars interested in the legacy of the Vienna Circle and its effect on ethics and philosophy of mind. (shrink)