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This paper examines the conceptions of logic from Leibniz, Hume, Kant, Frege, Wittgenstein and Ayer, and regards the six philosophers as the representatives of logical exceptionalism. From their standpoints, this paper refines the tenets of logical exceptionalism as follows: logic is exceptional to all other sciences because of four reasons: (i) logic is formal, neutral to any domain and any entities, and general; (ii) logical truths are made true by the meanings of logical constants they contain or by logicians' rational insight to consequence relations; (iii) logical truths are analytical, a prior and necessary, so not‐revisable; and (iv) logical laws are normative for how to correctly think. However, logical exceptionalism has encountered difficult open problems: What are logical constants? How to justify basic laws of logic? How are logical laws accessible to us? How to explain the reasonability of rival logics and select from them? How to explain the universal applicability of logical laws? How to explain the normativity of logical laws for correct thinking? This paper concludes that logical anti‐exceptionalism is more hopeful to successfully answer these questions than logical exceptionalism. [ABSTRACT FROM AUTHOR]

We present a new puzzle about logical truth, necessity, and moral responsibility. We defend one solution to the puzzle. A corollary of our preferred solution is that prominent arguments for the incompatibility of determinism and moral responsibility are invalid. [ABSTRACT FROM AUTHOR]

This paper compares two ways of holding that logic is special among the sciences in that it has no restricted class of entities as its subject matter, but instead concerns all entities alike. One way is Williamson’s explanation of how inquiry into logical consequence and logical truth only superficially concerns the linguistic or conceptual entities that bear these properties. Williamson draws on ideas familiar from deflationism about truth, and his account has been called “deflationary.” I argue that the analogy is misleading. While there’s a broad sense in which Williamson offers a deflationary account of logical inquiry, his view differs from deflationism about truth in being best understood as a form of instrumentalism. By contrast, I elaborate a deflationism about logical properties modeled on deflationism about truth. I defend this expressive device deflationism as an explanation of our use of logical predicates. [ABSTRACT FROM AUTHOR]

On 15 April 1630, in a letter to Mersenne, Descartes announced that on his view God creates the truths of mathematics. Descartes returned to the theme in subsequent letters and some of his Replies but nowhere is the view systematically developed and defended. It is not clear why Descartes came to espouse the creation doctrine, nor even what exactly it is. Some have argued that his motivation was theological, that God creates the eternal truths, including the truths of logic, because and insofar as God is omnipotent andthe creator of all things. I develop and defend a different reading according to which Descartes was led to espouse the creation doctrine by a fundamental shift in his understanding of the correct mode of inquiry in metaphysics and mathematics: by 1630, the God-created truths came to play the role in inquiry that until then, in the Rules for the Direction of the Mind, had been played by images.

Classical logic is often characterized through certain laws such as bi-valence and sharpness of concepts, among others. My view is that its most fundamental feature is a commitment to an objective conception of truth, which goes together with a realistic metaphysical view. Truth is objective in that it derives from the nature of reality and is not dependent on beliefs, theories, practices and the like. Classical logic is a theory of logical properties, logical truths and logical states of affairs. [ABSTRACT FROM AUTHOR]

On 15 April 1630, in a letter to Mersenne, Descartes announced that on his view God creates the truths of mathematics. Descartes returned to the theme in subsequent letters and some of his Replies but nowhere is the view systematically developed and defended. It is not clear why Descartes came to espouse the creation doctrine, nor even what exactly it is. Some have argued that his motivation was theological, that God creates the eternal truths, including the truths of logic, because and insofar as God is omnipotent and the creator of all things. I develop and defend a different reading according to which Descartes was led to espouse the creation doctrine by a fundamental shift in his understanding of the correct mode of inquiry in metaphysics and mathematics: by 1630, the God-created truths came to play the role in inquiry that until then, in the Rules for the Direction of the Mind, had been played by images. [ABSTRACT FROM AUTHOR]

Two types of logical consequence are compared: one, with respect to matrix and designated elements and the other with respect to ordering in a suitable algebraic structure. Particular emphasis is laid on algebraic structures in which there is no top-element relative to the ordering. The significance of this special condition is discussed. Sequent calculi for a number of such structures are developed. As a consequence it is re-established that the notion of truth as such, not to speak of tautologies, is inessential in order to define validity of an argument.

Many papers have been devoted to the semantic turn Carnap took in the late 1930s after Tarski had explained to him his method for defining truth and his work on the establishment of scientific semantics. Commentators have often argued that the major turn in Carnap's approach to languages had already been taken in the Logical Syntax of Language, but they have usually assumed that Carnap was happy to subsequently follow Tarski and adopt Tarskian semantics. In this paper, it is argued that this assumption needs to be qualified and that Carnap was actually far from following Tarski when he decided to complement his syntactic method with a semantic one. Carnap and Tarski had different goals, divergent programs, and dissenting views on truth and semantics. After exploring several possible methods for the explication of logical concepts such as L-truth and L-implication, Carnap opted for definitions based on concepts he had found in Wittgenstein's Tractatus and Waismann's work on a logical interpretation of probability. Carnap's reasons for taking a semantic turn are to be understood in the context of his principle of tolerance. He first hoped he could use Tarski's technique to recover in the semantic setting the completeness result he had tried to establish in the Logical Syntax. His eventual adoption of non-Tarskian semantics can be accounted for by his program of a logical analysis of science-including empirical science-and his ambition to elaborate a unified logical framework for deductive, inductive, and modal logic, and for explicating analyticity. [ABSTRACT FROM AUTHOR]

W. V. Quine thinks logical truth can be defined in purely extensional terms, as follows: a logical truth is a true sentence that exemplifies a logical form all of whose instances are true. P. F. Strawson objects that one cannot say what it is for a particular use of a sentence to exemplify a logical form without appealing to intensional notions, and hence that Quine's efforts to define logical truth in purely extensional terms cannot succeed. Quine's reply to this criticism is confused in ways that have not yet been noticed in the literature. This may seem to favour Strawson's side of the debate. In fact, however, a proper analysis of the difficulties that Quine's reply faces suggests a new way to clarify and defend the view that logical truth can be defined in purely extensional terms. [ABSTRACT FROM PUBLISHER]

Does general validity or real world validity better represent the intuitive notion of logical truth for sentential modal languages with an actuality connective? In (Philosophical Studies 130:436-459, ) I argued in favor of general validity, and I criticized the arguments of Zalta (Journal of Philosophy 85:57-74, ) for real world validity. But in Nelson and Zalta (Philosophical Studies 157:153-162, ) Michael Nelson and Edward Zalta criticize my arguments and claim to have established the superiority of real world validity. Section 1 of the present paper introduces the problem and sets out the basic issues. In Sect. 2 I consider three of Nelson and Zalta's arguments and find all of them deficient. In Sect. 3 I note that Nelson and Zalta direct much of their criticism at a phrase ('true at a world from the point of view of some distinct world as actual') I used only inessentially in Hanson (Philosophical Studies 130:436-459, ), and that their account of the philosophical foundations of modal semantics leaves them ill equipped to account for the plausibility of modal logics weaker than S5. Along the way I make several general suggestions for ways in which philosophical discussions of logical matters-especially, but not limited to, discussions of truth and logical truth for languages containing modal and indexical terms-might be facilitated and made more productive. [ABSTRACT FROM AUTHOR]

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The legacy of logical revisabilism is a hot issue in the philosophy of logic in China. Logical revisabilism holds that Quine is the source of this theory, and that non-classical logic is an instance of logical revision. Here, the reason for logical revisability is due to false descriptive elements in logic. Quine may not agree with logical revisabilism because he thinks that only first-order logic is the orthodox logic, there being no instance of logical revision. Logical revisabilists do not discuss the problem of logical revision on the same level. What's more, there is an unsolved problem with logical revisabilism, which is explaining "the false descriptive elements in logic." [ABSTRACT FROM AUTHOR]

Abstract: In this paper I analyze David Kaplanʼs essay “Opacity”. In “Opacity” Kaplan attempts to dismiss Quineʼs concerns about quantification across intensional (modal and intentional) operators. I argue that Kaplan succeeds in showing that quantification across intensional operators is logically coherent and that quantified modal logic is strictly speaking not committed to essentialism. However, I also argue that this is not in and of itself sufficient to support Kaplanʼs more ambitious attempt to move beyond purely logical results and provide unified, uncontroversial interpretations of both “believes” and “necessarily”. In the paper I raise several questions about the subject matter of logic and the role of semantics, with special focus on singular propositions. [Copyright &y& Elsevier]

Anti-realistic conceptions of truth and falsity are usually epistemic or inferentialist. Truth is regarded as knowability, or provability, or warranted assertability, and the falsity of a statement or formula is identified with the truth of its negation. In this paper, a non-inferentialist but nevertheless anti-realistic conception of logical truth and falsity is developed. According to this conception, a formula (or a declarative sentence) A is logically true if and only if no matter what is told about what is told about the truth or falsity of atomic sentences, A always receives the top-element of a certain partial order on non-ontic semantic values as its value. The ordering in question is a told-true order. Analogously, a formula A is logically false just in case no matter what is told about what is told about the truth or falsity of atomic sentences, A always receives the top-element of a certain told-false order as its value. Here, truth and falsity are pari passu, and it is the treatment of truth and falsity as independent of each other that leads to an informational interpretation of these notions in terms of a certain kind of higher-level information. [ABSTRACT FROM AUTHOR]

Logic has the function with the most essential truth, but also has extended from the pursuit of good features. Proposed and stressed the logic of seeking goodness features, it is helpful to improve the human spirits between the human beings' communications, to improve the innovative capability and innovative thinking, to foster the spirit of true logic while it can also provide a new concept of support the study of pre -- Qin logic ideas. [ABSTRACT FROM AUTHOR]

This article provides the first comprehensive reconstruction and analysis of Hintikka’s attempt to obtain a measure of the information yield of deductive inferences. The reconstruction is detailed by necessity due to the originality of Hintikka’s contribution. The analysis will turn out to be destructive. It dismisses Hintikka’s distinction between surface information and depth information as being of any utility towards obtaining a measure of the information yield of deductive inferences. Hintikka is right to identify the failure of canonical information theory to give an account of the information yield of deductions as a scandal, however this article demonstrates that his attempt to provide such an account fails. It fails primarily because it applies to only a restricted set of deductions in the polyadic predicate calculus, and fails to apply at all to the deductions in the monadic predicate calculus and the propositional calculus. Some corollaries of these facts are a number of undesirable and counterintuitive results concerning the proposed relation of linguistic meaning (and hence synonymy) with surface information. Some of these results will be seen to contradict Hintikka’s stated aims, whilst others are seen to be false. The consequence is that the problem of obtaining a measure of the information yield of deductive inferences remains an open one. The failure of Hintikka’s proposal will suggest that a purely syntactic approach to the problem be abandoned in favour of an intrinsically semantic one. [ABSTRACT FROM AUTHOR]

This article surveys all main aspects of Quine's language philosophy and traces the development of his views about truth. There will be close study and discussion of his views on meaning and truth, analyticity, holism, ontology and logic science and naturalism. [ABSTRACT FROM AUTHOR]

The traditional view that all logical truths are metaphysically necessary has come under attack in recent years. The contrary claim is prominent in David Kaplan’s work on demonstratives, and Edward Zalta has argued that logical truths that are not necessary appear in modal languages supplemented only with some device for making reference to the actual world (and thus independently of whether demonstratives like ‘I’, ‘here’, and ‘now’ are present). If this latter claim can be sustained, it strikes close to the heart of the traditional view. I begin this paper by discussing and refuting Zalta’s argument in the context of a language for propositional modal logic with an actuality connective (section 1). This involves showing that his argument in favor of real world validity his preferred explication of logical truth, is fallacious. Next (section 2) I argue for an alternative explication of logical truth called general validity. Since the rule of necessitation preserves general validity, the argument of section 2 provides a reason for affirming the traditional view. Finally (section 3) I show that the intuitive idea behind the discredited notion of real world validity finds legitimate expression in an object language connective for deep necessity. [ABSTRACT FROM AUTHOR]

The paper deals with the question whether logical truth carry information. On the one hand it seems that we gain new information by drawing inferences or arriving at some theorems. On the other hand the formal accounts of information and information content which are most widely known today say that logical truth carry no information at all. The latter is shown by considering these accounts. Then several ways to deal with the dilemma are distinguished, especially syntactic and ontological solutions. A version of a syntactical solution is favoured. [ABSTRACT FROM AUTHOR]