Citations of:
Add citations
You must login to add citations.


Intratheoretical logical pluralism is a form of meaninginvariant pluralism about logic, articulated recently by Hjortland :355–373, 2013). This version of pluralism relies on it being possible to define several distinct notions of provability relative to the same logical calculus. The present paper picks up and explores this theme: How can a single logical calculus express several different consequence relations? The main hypothesis articulated here is that the divide between the internal and external consequence relations in Gentzen systems generates a form (...) 

Starting from certain metalogical results, I argue that firstorder logical truths of classical logic are a priori and necessary. Afterwards, I formulate two arguments for the idea that firstorder logical truths are also analytic, namely, I first argue that there is a conceptual connection between aprioricity, necessity, and analyticity, such that aprioricity together with necessity entails analyticity; then, I argue that the structure of natural deduction systems for FOL displays the analyticity of its truths. Consequently, each philosophical approach to these (...) 

This paper presents an overview of the methods of hypersequents and display sequents in the proof theory of nonclassical logics. In contrast with existing surveys dedicated to hypersequent calculi or to display calculi, our aim is to provide a unified perspective on these two formalisms highlighting their differences and similarities and discussing applications and recent results connecting and comparing them. 

The discussions which follow rest on a distinction, first expounded by Husserl, between formal logic and formal ontology. The former concerns itself with (formal) meaningstructures; the latter with formal structures amongst objects and their parts. The paper attempts to show how, when formal ontological considerations are brought into play, contemporary extensionalist theories of part and whole, and above all the mereology of Leniewski, can be generalised to embrace not only relations between concrete objects and objectpieces, but also relations between what (...) 

A theory of definitions which places the eliminability and conservativeness requirements on definitions is usually called the standard theory. We examine a persistent myth which credits this theory to Le?niewski, a Polish logician. After a brief survey of its origins, we show that the myth is highly dubious. First, no place in Le?niewski's published or unpublished work is known where the standard conditions are discussed. Second, Le?niewski's own logical theories allow for creative definitions. Third, Le?niewski's celebrated ?rules of definition? lay (...) 

The focus of this paper are Dummett's meaningtheoretical arguments against classical logic based on consideration about the meaning of negation. Using Dummettian principles, I shall outline three such arguments, of increasing strength, and show that they are unsuccessful by giving responses to each argument on behalf of the classical logician. What is crucial is that in responding to these arguments a classicist need not challenge any of the basic assumptions of Dummett's outlook on the theory of meaning. In particular, I (...) 

John Cook Wilson (1849–1915) was Wykeham Professor of Logic at New College, Oxford and the founder of ‘Oxford Realism’, a philosophical movement that flourished at Oxford during the first decades of the 20th century. Although trained as a classicist and a mathematician, his most important contribution was to the theory of knowledge, where he argued that knowledge is factive and not definable in terms of belief, and he criticized ‘hybrid’ and ‘externalist’ accounts. He also argued for direct realism in perception, (...) 

Two different kinds of multipleconclusion consequence relations taken from Shoesmith and Smiley and Galatos and Tsinakis or Nowak, called here disjunctive and conjunctive, respectively, defined on a formal language, are considered. They are transferred into a bounded lattice and a complete lattice, respectively. The properties of such abstract consequence relations are presented. 

Logical pluralism as a thesis that more than one logic is correct seems very plausible for two basic reasons. First, there are so many logical systems on the market today. And it is unclear how we should decide which of them gets the logical rules right. On the other hand, logical monism as the opposite thesis still seems plausible, as well, because of normativity of logic. An approach which would manage to bring a synthesis of both logical pluralism and logical (...) 

The logic of assertive graphs is a modification of Peirce’s logic of existential graphs, which is intuitionistic and which takes assertions as its explicit object of study. In this paper we extend AGs into a classical graphical logic of assertions whose internal logic is classical. The characteristic feature is that both AGs and ClAG retain deepinference rules of transformation. Unlike classical EGs, both AGs and ClAG can do so without explicitly introducing polarities of areas in their language. We then compare (...) 

We are reliable about logic in the sense that we byandlarge believe logical truths and disbelieve logical falsehoods. Given that logic is an objective subject matter, it is difficult to provide a satisfying explanation of our reliability. This generates a significant epistemological challenge, analogous to the wellknown BenacerrafField problem for mathematical Platonism. One initially plausible way to answer the challenge is to appeal to evolution by natural selection. The central idea is that being able to correctly deductively reason conferred a (...) 

This article offers an overview of inferential role semantics. We aim to provide a map of the terrain as well as challenging some of the inferentialist’s standard commitments. We begin by introducing inferentialism and placing it into the wider context of contemporary philosophy of language. §2 focuses on what is standardly considered both the most important test case for and the most natural application of inferential role semantics: the case of the logical constants. We discuss some of the (alleged) benefits (...) 

The Linda paradox is a key topic in current debates on the rationality of human reasoning and its limitations. We present a novel analysis of this paradox, based on the notion of verisimilitude as studied in the philosophy of science. The comparison with an alternative analysis based on probabilistic confirmation suggests how to overcome some problems of our account by introducing an adequately defined notion of verisimilitudinarian confirmation. 





I sketch an application of a semantically antirealist understanding of the classical sequent calculus to the topic of mathematics. The result is a semantically antirealist defence of a kind of mathematical realism. In the paper, I begin the development of the view and compare it to orthodox positions in the philosophy of mathematics. 

In the paper the following questions are discussed: What is logical consequence? What are logical constants? What is a logical system? What is logical pluralism? What is logic? In the conclusion, the main tendencies of development of modern logic are pointed out. 

I finished my undergraduate degree at Monash University and joined Charles Hamblin’s seminar at the University of NSW in March, 1968. Phil Staines from the University of Newcastle joined at the same time, and Vic Dudman was an established member. Hamblin’s book Fallacies would be published in 1970, but the seminar discussions rarely concerned fallacies. This may have been because Hamblin had been working for so long and so closely with those ideas that he was now ready to turn elsewhere. (...) 

A good argument is one whose conclusions follow from its premises; its conclusions are consequences of its premises. But in what sense do conclusions follow from premises? What is it for a conclusion to be a consequence of premises? Those questions, in many respects, are at the heart of logic (as a philosophical discipline). Consider the following argument: 1. If we charge high fees for university, only the rich will enroll. We charge high fees for university. Therefore, only the rich (...) 

This paper examines causal theories of reference with respect to how plausible an account they give of nonphysical natural kind terms such as ‘gene’ as well as of the truth of the associated theoretical claims. I first show that reference fixism for ‘gene’ fails. By this, I mean the claim that the reference of ‘gene’ was stable over longer historical periods, for example, since the classical period of transmission genetics. Second, I show that the theory of partial reference does not (...) 

The semantics of noun phrases (NPs) is of crucial importance for both philosophy and linguistics. Throughout much of the history of the debate about the semantics of noun phrases there has been an implicit assumption about how they are to be understood. Basically, it is the assumption that NPs come only in two kinds. In this paper we would like to make that assumption explicit and discuss it and its status in the semantics of natural language. We will have a (...) 

According to logical inferentialists, the meanings of logical expressions are fully determined by the rules for their correct use. Two key prooftheoretic requirements on admissible logical rules, harmony and separability, directly stem from this thesis—requirements, however, that standard singleconclusion and assertionbased formalizations of classical logic provably fail to satisfy :1035–1051, 2011). On the plausible assumption that our logical practice is both singleconclusion and assertionbased, it seemingly follows that classical logic, unlike intuitionistic logic, can’t be accounted for in inferentialist terms. In (...) 

This thesis compares the concepts presented in the Seventeenth Discussion of alGhazali's Tahafut alFalasifa with concepts currently being discussed in the field of quantum physics. Written as an attack on the neoPlatonic and Aristotelian thinking which challenged the orthodox theology of Medieval Islam, Tahafut alFalasifa questions the understanding of physical reality forwarded by the philosophers of alGhazali's times. The Seventeenth Discussion in particular, with its aim of proving the possibility of miracles, questions the acceptance of notions such as necessary causality (...) 

Since at least the 1938 publication of Hans Reichenbach’s Experience and Predication , there has been widespread agreement that, when discussing the beliefs that people have, it is important to distinguish contexts of discovery and contexts of justification. Traditionally, when one conflates the two contexts, the result is a “genetic fallacy”. This paper examines genealogical critiques and addresses the question of whether such critiques are fallacious and, if so, whether this vitiates their usefulness. The paper concludes that while there may (...) 

Logic is usually thought to concern itself only with features that sentences and arguments possess in virtue of their logical structures or forms. The logical form of a sentence or argument is determined by its syntactic or semantic structure and by the placement of certain expressions called “logical constants.”[1] Thus, for example, the sentences Every boy loves some girl. and Some boy loves every girl. are thought to differ in logical form, even though they share a common syntactic and semantic (...) 

Inferentialism is the conviction that to be meaningful in the distinctively human way, or to have a 'conceptual content', is to be governed by a certain kind of inferential rules. The term was coined by Robert Brandom as a label for his theory of language; however, it is also naturally applicable (and is growing increasingly common) within the philosophy of logic. 

✤ It is the characterization of those forms of reasoning that lead invariably from true sentences to true sentences, independently of the subject matter. 

Since Kaplan : 81–98, 1979) first provided a logic for contextsensitive expressions, it has been thought that the only way to construct a logic for indexicals is to restrict it to arguments which take place in a single context— that is, instantaneous arguments, uttered by a single speaker, in a single place, etc. In this paper, I propose a logic which does away with these restrictions, and thus places arguments where they belong, in real world conversations. The central innovation is (...) 

En los trabajos publicados bajo el título general de ‘Lógica informal’ a lo largo de las últimas décadas es admitida la ausencia de una teoría con un grado generalizado de aceptación; lo mismo ocurre con respecto a la metodología. Bajo la hipótesis de que bajo estas circunstancias sería oportuno contar con alguna precisión en lo que se refiere al objetivo principal de la investigación, examinaré algunas caracterizaciones de la lógica informal que aparecen en artículos especializados recientes. Me orienta el propósito (...) 



It is argued, on the basis of ideas derived from Wittgenstein's Tractatus and Husserl's Logical Investigations, that the formal comprehends more than the logical. More specifically: that there exist certain formalontological constants (part, whole, overlapping, etc.) which do not fall within the province of logic. A twodimensional directly depicting language is developed for the representation of the constants of formal ontology, and means are provided for the extension of this language to enable the representation of certain materially necessary relations. The (...) 



The aim of this paper is show a global strategy for defining and connecting logical criteria. Three partial criteria are distinguished: transparency for expressions, topic neutrality for consequence relation, and universality for theories. A global criterion is suggested, and proved to be fulfilled by classical and intuionistic logic. 



The paper starts with an examination and critique of Tarski’s wellknown proposed explication of the notion of logical operation in the type structure over a given domain of individuals as one which is invariant with respect to arbitrary permutations of the domain. The class of such operations has been characterized by McGee as exactly those deﬁnable in the language L∞,∞. Also characterized similarly is a natural generalization of Tarski’s thesis, due to Sher, in terms of bijections between domains. My main (...) 

There have been several different and even opposed conceptions of the problem of logical constants, i.e. of the requirements that a good theory of logical constants ought to satisfy. This paper is in the first place a survey of these conceptions and a critique of the theories they have given rise to. A second aim of the paper is to sketch some ideas about what a good theory would look like. A third aim is to draw from these ideas and (...) 

This paper concentrates on how to capture harmony in sequent calculi. It starts by considering a proposal made by Tennant and some objections to it which have been presented by Steinberger. Then it proposes a different analysis which makes use of a doubleline presentation of sequent calculi in the style of Dosen and it shows that this proposal is able to dismiss disharmonious operators without thereby adopting any global criterion. 

In virtue of what are we justified in employing the rule of inference Modus Ponens? One tempting approach to answering this question is to claim that we are justified in employing Modus Ponens purely in virtue of facts concerning meaning or conceptpossession. In this paper, we argue that such meaningbased accounts cannot be accepted as the fundamental account of our justification. 

http://dx.doi.org/10.5007/18081711.2009v13n3p357 Neste trabalho concordase com a tese de I. Hacking segundo a qual o significado das constantes lógicas é dado pelas Regras de Introdução e Eliminação do cálculo de sequentes de Gentzen que caracterizam a concepção da noção de consequência lógica abstrata. Perguntamos quais são as regras mínimas que um conectivo deve satisfazer para que seja considerado uma negação genuína. Tomaremos como referência para tratar dessa questão os Csistemas de Newton da Costa e o sistema LP de Graham Priest. Finalmente, (...) 

The pretheoretical notions of logical consequence and of a logical expression are linked in vague and complex ways to modal and pragmatic intuitions. I offer an introduction to the difficulties that these intuitions create when one attempts to give precise characterizations of those notions. Special attention is given to Tarski’s theories of logical consequence and logical constancy. I note that the Tarskian theory of logical consequence has fared better in the face of the difficulties than the Tarskian theory of logical (...) 



Resumo: Pedro Hispano define os sincategoremas como expressões que revelam de que maneira os sujeitos e os predicados estão de fato relacionados nas proposições, contribuindo assim para o estabelecer o que elas significam e fixar as condições de verdade e as formas lógicas correspondentes. Entre as expressões que ele julga serem sincategoremáticas, ‘não’, ‘e’, ‘ou’, ‘se’, ‘todo’ e ‘necessário’ se destacam atualmente como constantes lógicas. Todavia, opondose a grande parte dos lógicos contemporâneos para quem tais expressões possuem um significado fixo (...) 



I discuss paradoxes of implication in the setting of a proofconditional theory of meaning for logical constants. I argue that a proper logic of implication should be not only relevant, but also constructive and nonmonotonic. This leads me to select as a plausible candidate LL, a fragment of linear logic that differs from R in that it rejects both contraction and distribution. 

Logicism is, roughly speaking, the doctrine that mathematics is fancy logic. So getting clear about the nature of logic is a necessary step in an assessment of logicism. Logic is the study of logical concepts, how they are expressed in languages, their semantic values, and the relationships between these things and the rest of our concepts, linguistic expressions, and their semantic values. A logical concept is what can be expressed by a logical constant in a language. So the question “What (...) 



It is often claimed that nominalistic programmes to reconstruct mathematics fail, since they will at some point involve the notion of logical consequence which is unavailable to the nominalist. In this paper we use an idea of Goodman and Quine to develop a nominalistically acceptable explication of logical consequence. 

“The confusion of a logical with a real predicate,” according to the Critique of Pure Reason, “is almost beyond correction”. Kant did not assert that existence is no predicate, but that it is only a “logical” one, and not a “real” one. Much the same thing has been said about identity, although Kant himself thought it is real and not logical. We have long lacked a rigorous criterion to distinguish real from logical predicates, and hence have not been able to (...) 

Ian Hacking's [6] is a spirited romp though a broad field of metaphysics, touching on a variety of important questions, and appealing to deep results in mathematical logic while remaining free of logical pedantry. Philosophical journals might be more fun to read if others could write in his style. It is an essay in applying the theory of logic expounded in more detail in his very interesting [7]. Unfortunately, despite my sympathy for his project, I have a number of criticisms (...) 