Any "classical" theory of truth will satisfy tarski's criterion ("p" is true if and only if p), And the principle of bivalence (every proposition is either true or false). A non-Classical theory may be obtained by rejecting these principles: - in fact it is shown that rejection of the second entails rejection of the first. If the resulting non-Classical theory is formalized, A system structurally isomorphic to either s4 or s5 is obtained. An (...) attempt is made to show that the essential insights of intuitionist logic may be preserved if we replace their complex and in many respects "unintuitive" propositional logic by a theory of truth which is non-Classical in the sense described above. (shrink)

The article is about one of the vital problem for analytic philosophy which is how to define truth value for sentences which include their own truth predicate. The aim of the article is to determine Saul Kripke’s approach to widen epistemological truth to create a systemic model of truth. Despite a lot of work on the subject, the theme of truth is no less relevant to modern philosophy. With the help of S. Kripke’s article “Outline (...) of the Theory of Truth” and R. L. Kirkham’s work “Theories of Truth: A Critical Introduction” the author tried to represent a non-classical approach which is now known as Saul Kripke’s truth value gaps theory. Considering his solving of the Liar Paradox, as well as the Strenghened Liar, it is obvious that there could be the circumstances (or facts) that make sentences have no truth value. In that case the solving of the paradox attracts Kleene’s non-classical three-valued logic which contains the third way and the solution falls into the gap between truth and falsity. Hence there are no relevant and full satisfactory ways to solve the Liar’s Paradox by the language-levels ap- proach. The task consists in an extension of the approach to natural languages and elimination of an ad hoc element as well. Besides that, the language-levels approach refers to the speaker that means that only the last one is allowed to define the hierarchy of the levels and truth value of sentence, but often he does not know what level he is speaking of. As Kripke stated, contingent facts can lead to a paradox which isn’t allowed for a logical point of view. However usage of mathematical apparatus allows the theory in question to be universalized and moreover paves the way to futher epistemological develop- ment of the problem in question. As Kripke’s theory is formalized and presented as a functional series, it gives access to a system model of truth whose elements would be epistemological theories (concepts) of truth. Such a model, for instance, confirms the validity of the deflationary concept of truth. Refs 7. (shrink)

The paradoxes about truth are the subject of extensive research. Developing an original approach, this book argues that we should diverge from classical logic and presents a number of formal theories of truth. Also included is a beginner-friendly introduction to semantic paradoxes, and a discussion of alternative non-classical theories.

One of the most intuitive concepts of truth is the classical correspondence theory of truth. Aside from the theoretical cogency and plausibility, this truth theory has two fundamental problems. I shall explore both of these problems. This will not be to reveal the problematic nature of the classical correspondence theory of truth itself, but to demonstrate the implications it has on Islam. I shall establish that the problems of this truth (...) theory contribute in the failure to determine the truth of a particular notion of an Islamic God. Consequently this truth theory would prove inconsistent with a particular notion of God within the Islamic tradition. (shrink)

Alfred Tarski’s theory of truth, to which we will also refer as the classical theory,1 has a conspicuous place in mathematics as well as in general philosophy. The place in philosophy appears the more prominent of the two, although it is still somewhat unsettled, and perhaps even controversial.

The article examines main competing conceptions of the cor­respondence theory of truth. First, the author investigates pos­sible candidates for the role of truth-bearers. Among those he examines following entities: instances of sentences as concrete sequences of symbols (sounds or letters), which should satisfy wide scope of requirements, such as to be grammatical, mean­ingful, affirmative and so on; abstract propositions, which are ex­pressed by concrete sentences; utterances (either explicit or in lingua mentalis); beliefs of agents as their special (...) mental states. Then he turns to the study of possible candidates for the role of truth-makers, i.e. of those entities to which truth-bearers should correspond to be true. He observes states of affairs, situations, facts and mereological sums of individuals. Then he shows that a notion of correspondence is a functional relationship of interpre­tation of linguistic expressions, where certain fragment of real­ity is taken as a model, i.e. as a finite set of elements on which some functions and relations can be operationally defined. He shows how in some simple cases such interpretation function can be built in operationalist’s manner. After that, he considers some natural objections to this approach, which point that he has no direct cognitive access to the actual world, so it is not possible to take its fragments as a model for any theory. Such objections lead us to the coherentist’s approach, but he shows that the question about origin and status of so-called “specified set” implicitly either leads to infinite regress or requires certain correspondence on some level of investigation and reasoning. Finally, the authore presents some reflections on the meaning of correspondence approach for scientific realism and all other versions of realistic philosophy and metaphysics. (shrink)

Definitional and axiomatic theories of truth -- Objects of truth -- Tarski -- Truth and set theory -- Technical preliminaries -- Comparing axiomatic theories of truth -- Disquotation -- Classical compositional truth -- Hierarchies -- Typed and type-free theories of truth -- Reasons against typing -- Axioms and rules -- Axioms for type-free truth -- Classical symmetric truth -- Kripke-Feferman -- Axiomatizing Kripke's theory in partial logic -- Grounded (...) truth -- Alternative evaluation schemata -- Disquotation -- Classical logic -- Deflationism -- Reflection -- Ontological reduction -- Applying theories of truth. (shrink)

Nonclassical theories of truth have in common that they reject principles of classical logic to accommodate an unrestricted truth predicate. However, different nonclassical strategies give up different classical principles. The paper discusses one criterion we might use in theory choice when considering nonclassical rivals: the maxim of minimal mutilation.

The main argument of the book under review, 'Theories of Truth in Chinese Philosophy,' is to show that one can find a pluralistic theory of shí 實 in the Lunheng, “prepared” by a range of sources in the Warring States Period in China. This argument is not convincing because of small inconsistencies and major unsupported stipulations. Nevertheless the book contains many perceptive and suggestive remarks concerning the texts discussed.

This chapter attempts to give a brief overview of nonclassical (-logic) theories of truth. Due to space limitations, we follow a victory-through-sacrifice policy: sacrifice details in exchange for clarity of big-picture ideas. This policy results in our giving all-too-brief treatment to certain topics that have dominated discussion in the non-classical-logic area of truth studies. (This is particularly so of the ‘suitable conditoinal’ issue: §4.3.) Still, we present enough representative ideas that one may fruitfully turn from this essay (...) to the more-detailed cited works for further study. Throughout – again, due to space – we focus only on the most central motivation for standard non-classical-logic-based truth theories: namely, truth-theoretic paradox (specifically, due to space, the liar paradox). (shrink)

We investigate axiomatizations of Kripke's theory of truth based on the Strong Kleene evaluation scheme for treating sentences lacking a truth value. Feferman's axiomatization KF formulated in classical logic is an indirect approach, because it is not sound with respect to Kripke's semantics in the straightforward sense: only the sentences that can be proved to be true in KF are valid in Kripke's partial models. Reinhardt proposed to focus just on the sentences that can be proved (...) to be true in KF and conjectured that the detour through classical logic in KF is dispensable. We refute Reinhardt's Conjecture, and provide a direct axiomatization PKF of Kripke's theory in partial logic. We argue that any natural axiomatization of Kripke's theory in Strong Kleene logic has the same proof-theoretic strength as PKF, namely the strength of the system RA< ωω ramified analysis or a system of Tarskian ramified truth up to ωω. Thus any such axiomatization is much weaker than Feferman's axiomatization KF in classical logic, which is equivalent to the system RA<ε₀ of ramified analysis up to ε₀. (shrink)

The classic and contemporary readings in this collection represent the four most influential theories of truth – correspondence, pragmatist, coherence, and deflationary theories. A collection of classic and contemporary philosophical reflections on the nature of truth. Opens with an introduction to theories of truth, designed for readers with little or no prior knowledge of the subject. Divided into four sections on the most important theories of truth - correspondence, pragmatist, coherence, and deflationary theories. Brings together articles (...) in the recent debate over the correspondence theory and deflationism that are not otherwise available in one place. Includes contributions by C.S. Peirce, William James, Bertrand Russell, Alfred Tarski, Hartry Field, Dorothy Grover, Anil Gupta and others. Concludes with an extensive bibliography of recent articles on truth. (shrink)

The classic and contemporary readings in this collection represent the four most influential theories of truth – correspondence, pragmatist, coherence, and deflationary theories. A collection of classic and contemporary philosophical reflections on the nature of truth. Opens with an introduction to theories of truth, designed for readers with little or no prior knowledge of the subject. Divided into four sections on the most important theories of truth - correspondence, pragmatist, coherence, and deflationary theories. Brings together articles (...) in the recent debate over the correspondence theory and deflationism that are not otherwise available in one place. Includes contributions by C.S. Peirce, William James, Bertrand Russell, Alfred Tarski, Hartry Field, Dorothy Grover, Anil Gupta and others. Concludes with an extensive bibliography of recent articles on truth. (shrink)

Some axiomatic theories of truth and related subsystems of second-order arithmetic are surveyed and shown to be conservative over their respective base theory. In particular, it is shown by purely finitistically means that the theory PA ÷ "there is a satisfaction class" and the theory FS of [2] are conservative over PA.

Vol 1. Substance truth and person -- vol 2. Perfecting reality -- vol 3. Practical implication -- vol 4. The idealist theory of truth.

The sentences employed in semantic paradoxes display a wide range of semantic behaviours. However, the main theories of truth currently available either fail to provide a theory of paradox altogether, or can only account for some paradoxical phenomena by resorting to multiple interpretations of the language. In this paper, I explore the wide range of semantic behaviours displayed by paradoxical sentences, and I develop a unified theory of truth and paradox, that is a theory of (...) truth that also provides a unified account of paradoxical sentences. The theory I propose here yields a threefold classification of paradoxical sentences – liar-like sentences, truth-teller-like sentences, and revenge sentences. Unlike existing treatments of semantic paradox, the theory put forward in this paper yields a way of interpreting all three kinds of paradoxical sentences, as well as unparadoxical sentences, within a single model. (shrink)

It is widely accepted that a theory of truth for arithmetic should be consistent, but -consistency is a highly desirable feature for such theories. The point has already been made for first-order languages, though the evidence is not entirely conclusive. We show that in the second-order case the consequence of adopting -inconsistent theories of truth are considered: the revision theory of nearly stable truth T # and the classical theory of symmetric truth (...) FS. Briefly, we present some conceptual problems with ω-inconsistent theories, and demonstrate some technical results that support our criticisms of such theories. (shrink)

The liar and kindred paradoxes show that we can derive contradictions if our language possesses sentences lending themselves to paradox and we reason classically from schema about truth: Sis true iffp, where the letter p is to be replaced with a sentence and the letter S with a name of that sentence. This article presents a theory of truth that keeps at the expense of classical logic. The theory is couched in a language that possesses (...) paradoxical sentences. It incorporates all the instances of the analogue of for that language and also includes other platitudes about truth. The theory avoids contradiction because its logical framework is an appropriately constructed nonclassical propositional logic. The logic and the theory are different from others that have been proposed for keeping, and the methods used in the main proofs are novel. (shrink)

A lot has been written on solutions to the semantic paradoxes, but very little on the topic of general theories of paradoxicality. The reason for this, we believe, is that it is not easy to disentangle a solution to the paradoxes from a specific conception of what those paradoxes consist in. This paper goes some way towards remedying this situation. We first address the question of what one should expect from an account of paradoxicality. We then present one conception of (...) paradoxicality that has been offered in the literature: the fixed-point conception. According to this conception, a statement is paradoxical if it cannot obtain a classical truth-value at any fixed-point model. In order to assess this proposal rigorously we provide a non-metalinguistic characterization of paradoxicality and we evaluate whether the resulting account satisfies a number of reasonable desiderata. (shrink)

The focus in this essay will be upon the paradoxes, and foremostly in set theory. A central result is that the librationist set theory £ extension \Pfund $\mathscr{HR}(\mathbf{D})$ of \pounds \ accounts for \textbf{Neumann-Bernays-Gödel} set theory with the \textbf{Axiom of Choice} and \textbf{Tarski's Axiom}. Moreover, \Pfund \ succeeds with defining an impredicative manifestation set $\mathbf{W}$, \emph{die Welt}, so that \Pfund$\mathscr{H}(\mathbf{W})$ %is a model accounts for Quine's \textbf{New Foundations}. Nevertheless, the points of view developed support the view that (...) the truth-paradoxes and the set-paradoxes have common origins, so that the librationist resolutions of the set theoretic paradoxes are at the same time resolutions of the truth theoretic paradoxes. Both the librationist resolutions of the set theoretic paradoxes and the truth theoretic paradoxes have non-trivial philosophical implications: librationist set theories have the consequence that there are no absolutely uncountable sets, and librationist truth theories allow the use of syntactical modalities in ways which circumvent limitations as those of \parencite{Montague1963}, and a truth predicate which is useful for more precise philosophical discourse. (shrink)

In fourth-century Greece, the debate over the nature of philosophy generated a novel claim: that the highest form of wisdom is theoria, the rational 'vision' of metaphysical truths. This 2004 book offers an original analysis of the construction of 'theoretical' philosophy in fourth-century Greece. In the effort to conceptualise and legitimise theoretical philosophy, the philosophers turned to a venerable cultural practice: theoria. In this practice, an individual journeyed abroad as an official witness of sacralized spectacles. This book examines the philosophic (...) appropriation and transformation of theoria, and analyses the competing conceptions of theoretical wisdom in fourth-century philosophy. By tracing the link between traditional and philosophic theoria, this book locates the creation of theoretical philosophy in its historical context, analysing theoria as a cultural and an intellectual practice. It develops a new, interdisciplinary approach, drawing on philosophy, history and literary studies. (shrink)

We expand on the fixed point semantic approach of Kripke via the addition of two unary intensional operators: a paradoxicality operator Π where Π(Φ) is true at a fixed point if and only if Φ is paradoxical (i.e., if and only if Φ receives the third, non-classical value on all fixed points that extend the current fixed point), and an unbounded truth operator Υ⊤ where Υ⊤(Φ) is true at a fixed point if and only if any fixed point (...) extending the current fixed point can be extended to one on which Φ receives the value true. We prove a generalized version of Kripke’s fixed point theorem guaranteeing the existence of models of this new language, as well as an expressive completeness result. We conclude with an exploration of the significant improvements in expressive power that result from the addition of these new operators, and we precisely identify what still cannot be said on this intensional extension of the Kripkean framework. (shrink)

We study the relationships between two clusters of axiomatizations of Kripke’s fixed-point models for languages containing a self-applicable truth predicate. The first cluster is represented by what we will call ‘\-like’ theories, originating in recent work by Halbach and Horsten, whose axioms and rules are all valid in fixed-point models; the second by ‘\-like’ theories first introduced by Solomon Feferman, that lose this property but reflect the classicality of the metatheory in which Kripke’s construction is carried out. We show (...) that to any natural system in one cluster—corresponding to natural variations on induction schemata—there is a corresponding system in the other proving the same sentences true, addressing a problem left open by Halbach and Horsten and accomplishing a suitably modified version of the project sketched by Reinhardt aiming at an instrumental reading of classical theories of self-applicable truth. (shrink)

This paper explores the interface between principles of self-applicable truth and classical logic. To this end, the proof-theoretic strength of a number of axiomatic theories of truth over intuitionistic logic is determined. The theories considered correspond to the maximal consistent collections of fifteen truth-theoretic principles as isolated in Leigh and Rathjen.

The paper presents Alfred Tarski’s debate with the semantic antinomies: the basic Liar Paradox, and its more sophisticated versions, which are currently discussed in philosophy: Strengthen Liar Paradox, Cyclical Liar Paradox, Contingent Liar Paradox, Correct Liar Paradox, Card Paradox, Yablo’s Paradox and a few others. Since Tarski, himself did not addressed these paradoxes—neither in his famous work published in 1933, nor in later papers in which he developed the Semantic Theory of Truth—therefore, We try to defend his concept (...) of truth against these antinomies. It is demonstrated that Tarskian theory of truth is resistant to the paradoxes and it is still the best solution to avoid the antinomies and remain within a classical logic, that is, accepting the laws of noncontradiction, excluded middle, and the principle of bivalence. Thus, the goal of the paper is double—firstly, to show that none of the versions of the Liar Paradox’s is a serious threat to Tarski’s concept of truth, and secondly, that Semantic Theory of Truth allows to remain within classical logic, and at the same time, avoid antinomies—which makes it the most attractive among classical theories of truth. (shrink)

Closure is the idea that what is true about a theory of truth should be true in it. Commitment to closure under truth motivates non-classical logic; commitment to closure under validity leads to substructural logic. These moves can be thought of as responses to revenge problems. With a focus on truth in mathematics, I will consider whether a noncontractive approach faces a similar revenge problem with respect to closure under provability, and argue that if a (...) noncontractive theory is to be genuinely closed, then it must be free of all contraction, even in the metatheory. (shrink)

Being the most intuitive and yet perhaps most contestable of all, the correspondence theory remains an axis around which the philosophical debate on truth incessantly spins, with indefiniteness remaining as its main propelling force. The following work presents one more interpretative attempt; it will be argued that each classical contemporary version of the theory incorporates an idea of translation process. For this purpose, initially one was specified what notion of translation should be applied here by enumerating (...) its key features. Next, three classical models were examined—those proposed by Russell, Moore and Austin—in such a way as to expose the place of translation in each analysis. Consequently, the research both provide an element which unifies them and highlight the significance of translation for the philosophical inquiry into the concept of truth. (shrink)

The paper explores applications of Kripke's theory of truth to semantics for anti-luck epistemology, that is, to subjunctive theories of knowledge. Subjunctive theories put forward modal or subjunctive conditions to rule out knowledge by mere luck as to be found in Gettier-style counterexamples to the analysis of knowledge as justified true belief. Because of the subjunctive nature of these conditions the resulting semantics turns out to be non-monotone, even if it is based on non-classical evaluation schemes such (...) as strong Kleene or FDE. This blocks the usual road to fixed-point results for Kripke's theory of truth within these semantics and consequently the paper is predominantly an exploration of fixed point results for Kripke's theory of truth within non-monotone semantics. Using the theory of quasi-inductive definitions we show that in case of the subjunctive theories of knowledge the so-called Kripke jump will have fixed points despite the non-monotonicity of the semantics: Kripke's theory of truth can be successfully applied in the framework of subjunctive theories of knowledge. (shrink)

Against blanshard's classic argument for coherence, i maintain that coherence is neither the sole criterion nor nature of truth. in the face of blanshard's insistence that, since truth cannot be a matter of correspondence it must necessarily be a matter of coherence, i propose and defend a third option which combines the two polar positions. i develop this option through analysis of kant's writings on truth.

The ambiguity theory of “knows” is the view that knows and its cognates have more than one propositional sense—i.e., more than one sense that can properly be used in “knows that” etc. constructions. The ambiguity theory of “know” has received relatively little attention as an account of the truth-conditions for knowledge ascriptions and denials—especially compared to views like classical, moderate invariantism and epistemic contextualism. In this paper, it is argued that the ambiguity theory of knows (...) has an advantage over both classical, moderate invariantism and epistemic contextualism. This advantage is that it is the only one of these views that can account for “diverging knowledge responses without inconsistency” —i.e., cases in which, for the same subject S and proposition p, one and the same speaker says truly “S knows p” but instead could have truly said “S does not know p” and vice versa. This paper argues both for the existence of DRWI scenarios and the ability of the ambiguity theory of knows to best explain their existence. (shrink)

Based on a crowdsourced truth value judgment experiment, we provide empirical evidence challenging two classical views in semantics, and we develop a novel account of counterfactuals that combines ideas from inquisitive semantics and causal reasoning. First, we show that two truth-conditionally equivalent clauses can make different semantic contributions when embedded in a counterfactual antecedent. Assuming compositionality, this means that the meaning of these clauses is not fully determined by their truth conditions. This finding has a clear (...) explanation in inquisitive semantics: truth-conditionally equivalent clauses may be associated with different propositional alternatives, each of which counts as a separate counterfactual assumption. Second, we show that our results contradict the common idea that the interpretation of a counterfactual involves minimizing change with respect to the actual state of affairs. We propose to replace the idea of minimal change by a distinction between foreground and background for a given counterfactual assumption: the background is held fixed in the counterfactual situation, while the foreground can be varied without any minimality constraint. (shrink)

Platon zählt zu den einflussreichsten Philosophen aller Zeiten. Er beeinflusste maßgeblich Profil und Kanon der westlichen Philosophie. Die Kritik am sogenannten Platonismus wurde kontinuierlich von den Schwierigkeiten gespeist, die die Interpretation der philosophischen Schriften Platons bereitet. Gemeinhin wird er als rein rationaler Philosoph gesehen. Ein Philosoph war er in der Tat, ebenso jedoch ein Experte in der Annäherung an das Nicht-Rationale, unter anderem in Form von Mythen. So wurde er auch als "Mythenerfinder" und "Mythologe" bezeichnet. Platon war ein Visionär, der (...) es wagte, das Reich des Nicht-Rationalen auf systematische und disziplinierte Art zu erforschen. Insgesamt lässt sich Platons philosophisches Vorhaben als Streben nach einer umfassenden Sicht des organischen Ganzen klassifizieren. Der Ausdruck „Gestalt“ scheint die Ganzheit am ehesten zu beschreiben. Platon kann als prominentester und auch als letzter Repräsentant der antiken Philosophie angesehen werden, der die Entwicklung einer Gestalt-Philosophie anstrebte. Plato is one of the most influential philosophers of all time. He decisively shaped the profile and canon of western philosophy. Criticism of what has become known as Platonism has been continuously nourished by the difficulties of interpreting this philosopher's writings. Plato is commonly viewed as a purely rational philosopher. A philosopher he was indeed, but Plato was also an expert in approaching the non-rational, in the form of mythology among others. Plato has been called a "mythmaker" and a "mythologist". Plato was a visionary who dared to explore the realm of the non-rational in a systematic and disciplined way. In an overall comparison, Plato's philosophical enterprise strives for a comprehensive perspective on the organic whole. The expression "Gestalt" seems to come closest to describing the wholeness. Plato may be considered to be the most prominent representative of classical philosophy to develop a Gestalt philosophy and also the last to do so in antiquity. (shrink)

This article informally presents a solution to the paradoxes of truth and shows how the solution solves classical paradoxes (such as the original Liar) as well as the paradoxes that were invented as counterarguments for various proposed solutions (“the revenge of the Liar”). This solution complements the classical procedure of determining the truth values of sentences by its own failure and, when the procedure fails, through an appropriate semantic shift allows us to express the failure in (...) a classical two-valued language. Formally speaking, the solution is a language with one meaning of symbols and two valuations of the truth values of sentences. The primary valuation is a classical valuation that is partial in the presence of the truth predicate. It enables us to determine the classical truth value of a sentence or leads to the failure of that determination. The language with the primary valuation is precisely the largest intrinsic fixed point of the strong Kleene three-valued semantics (LIFPSK3). The semantic shift that allows us to express the failure of the primary valuation is precisely the classical closure of LIFPSK3: it extends LIFPSK3 to a classical language in parts where LIFPSK3 is undetermined. Thus, this article provides an argumentation, which has not been present in contemporary debates so far, for the choice of LIFPSK3 and its classical closure as the right model for the truth predicate. In the end, an erroneous critique of Kripke-Feferman axiomatic theory of truth, which is present in contemporary literature, is pointed out. (shrink)

With his influence on the development of physiology, physics and geometry, Hermann von Helmholtz – like few scientists of the second half of the 19th century – is representative of the research in natural science in Germany. The development of his understanding of science is not less representative. Until the late sixties, he emphatically claimed the truth of science; later on, he began to see the conditions for the validity of scientific knowledge in relative terms, and this can, in (...) summary, be referred to as hypothesizing. Already in the past century, HeImholtz made first approaches to an understanding of science, which were incompatible with his own former position and which pointed to the modern age to an astonishingly large extent. A comparison with Karl R. Popper's logic of research will illustrate how closely he nevertheless approached modern understanding of science. In Popper's logic of research, hypothesizing of scientific knowledge is definitely much more advanced than in Helmholtz's theory of science. What begins vaguely to emerge with Helmholtz has already become an explicitly formulated programme with Popper. Although HeImholtz and Popper are not on a direct line of epistemological development and Popper refers to HeImholtz only rarely and casually, there are in fact surprising points of contact which have not been taken notice of so far and which appear above all if one looks at Helmholtz's understanding of science against the background of Popper's logic of research. (shrink)

The nature of truth has occupied philosophers since the very beginning of the field. Our goal is to clarify the notion of scientific truth, in particular the notion of partial truth of facts. Our strategy consists to brake the problem into smaller, more manageable, questions. Thus, we distinguish the truth of a scientific theory, what we call the "global" truth value of a theory, from the truth of a particular scientific proposition, what (...) we call the "local" truth values of a theory. We will present a new local theory of partial truth and will have few things to say about the global level. Moreover, we will also introduce some purely formal results, the most important being the introduction of a new class of algebraic structures which have some interesting connections with classical logic. (shrink)

Peirce's conception of truth in terms of the final opinion reached in the long run by a community of inquirers marks a significant departure from traditional conceptions of truth, not only because it introduces a temporal dimension, but also because it explicitly connects it to groups of people and to what those people do. If we compare this with Aristotle's classic definition—"to say of what is that it is, and of what is not that it is not"2—we see (...) that there is no temporal dimension there and that it solely references an individual. In fact, truth is often cast as a correspondence between objects and their representation, in thought, language, or art, without any reference to those who think, speak, or paint, or... (shrink)

The aim of this paper is to introduce a formal system STW of self-referential truth, which extends the classical first-order theory of pure combinators with a truth predicate and certain approximation axioms. STW naturally embodies the mechanisms of general predicate application/abstraction on a par with function application/abstraction; in addition, it allows non-trivial constructions, inspired by generalized recursion theory. As a consequence, STW provides a smooth inner model for Myhill's systems with levels of implication.

In lieu of an abstract, here is a brief excerpt of the content:Reviewed by:Living the Truth: A Theory of ActionBenjamin J. BrownLiving the Truth: A Theory of Action Klaus Demmer Washington, D.C.: Georgetown University Press, 2010. 179 pp. $34.95.Klaus Demmer is one of the most influential Catholic moral theologians in Europe since Vatican II. Unfortunately, he is relatively unknown in America. Living the Truth is only the second of his works to be translated into English, (...) although other translations are anticipated. In Living the Truth, Demmer provides an incredibly balanced and nuanced work of fundamental moral theology and brims with insights. Not content with easy answers or oversimplifications, Demmer seeks in this book not only to chart a way between apparent opposites but also to synthesize the best of both into a new unity.For example, Demmer returns regularly to the question of the foundation and role of moral norms. Norms are indispensable in the life of the “ethical personality,” the person who is fully alive as a human being. They serve to open a person to the truth and to freedom and help to make a space for genuinely good, free, and vibrant action. However, norms are not at the heart of Demmer’s ethics, either as a discipline or in actual life. He also speaks of the ways in which a person establishes norms for herself even as he is careful to avoid relativism or subjectivism. Acknowledging that norms derived from a natural law ethics are true and important and that Christian morality may not be able to add any propositional content to natural law, he also argues at length that Christianity does in fact significantly shape a natural law ethics into something that is both deeper and more expansive. For Demmer, the Christian context changes the basis and meaning of morality. Although frustratingly spare with examples, he brings to the fore the difference between grounding human dignity in human nature as reason can grasp it and grounding it more specifically in the image and likeness of God and the love shown in the incarnation and redemption.Demmer’s moral theology is profoundly human and existential; it is immersed in the context and texture of real human experience. In many ways, it is very pastoral. It certainly manifests a depth of psychological insight into the nature and workings of the human mind, for example, in analyzing the ways in which people fall into pride and self-deception (33–37).Living the Truth’s concern with truth and truthfulness is an important and timely theme. Once again, Demmer synthesizes distinct elements. Truthfulness is a multifaceted reality, referring both to internal and external forces. Systematically [End Page 227] grounding his ethics in a robust classical metaphysic, Demmer understands the “true,” the “good,” and “being” to be related as transcendentals (42). The “truth” opens one up to “goodness,” which in turn allows for the flourishing of the human person. Far from being restrictive, the truth opens up possibilities for true freedom. But this only occurs when it is internalized as “truthfulness,” a virtue of many dimensions that Demmer unfolds throughout the book, particularly in the last of the three main parts.Living the Truth is very dense. It definitely is not an undergraduate text. Both the meaning of individual sentences and the flow of Demmer’s thought are elusive at times. Many subsections discuss a range of ideas and seem at times to wander. Even readers with a strong background in moral theology will find it necessary to reread and think carefully in order to catch the precise meaning of specific phrases and follow the argument. Nonetheless, the rewards are well worth the effort. Every moral theologian owes it to herself to read this book. [End Page 228]Benjamin J. BrownLourdes UniversityCopyright © 2012 Society of Christian Ethics... (shrink)

In this important new text, Keith Lehrer introduces students to the major traditional and contemporary accounts of knowing. Beginning with the accepted definition of knowledge as justified true belief, Lehrer explores the truth, belief and justification conditions on the way to a thorough examination of foundation theories of knowledge, externalism and naturalized epistemologies, internalism and modern coherence theories as well as recent reliabilist and causal theories. Lehrer gives all views careful examination and concludes that external factors must be matched (...) by appropriate internal ones to yield knowledge. Readers of Professor Lehrer's earlier book _Knowledge_ will want to know that this text adopts the framework of that classic text. But _Theory of Knowledge_ is a completely rewritten and updated version of that book that has been simplified throughout for student use. (shrink)

In this important new text, Keith Lehrer introduces students to the major traditional and contemporary accounts of knowing. Beginning with the accepted definition of knowledge as justified true belief, Lehrer explores the truth, belief and justification conditions on the way to a thorough examination of foundation theories of knowledge, externalism and naturalized epistemologies, internalism and modern coherence theories as well as recent reliabilist and causal theories. Lehrer gives all views careful examination and concludes that external factors must be matched (...) by appropriate internal ones to yield knowledge. Readers of Professor Lehrer's earlier book _Knowledge_ will want to know that this text adopts the framework of that classic text. But _Theory of Knowledge_ is a completely rewritten and updated version of that book that has been simplified throughout for student use. (shrink)

We start with a nearly arbitrary standard classical first order "language" $C\sb{o},$ which is expanded to $C\sb{M,T}$ = "$C\sb{o}+M+T$", where for any variable x, M and T are unary formulas. We start also with a model ${\cal T}\sb{o},$ which together with $C\sb{o}$ represents a fixed non-problematic interpreted first order language. For each $\mu,\tau\subseteq U\sb{o},$ the universe of discourse for ${\cal T}\sb{o},$ the model ${\cal T}\sb{\mu,\tau}$ over $C\sb{M,T}$ is given so that its reduct to $C\sb{o}$ is just ${\cal T}\sb{o},$ and (...) so that for any $C\sb{M,T}$-variable x, the set-extensions of M and T are $\mu$ and $\tau$ respectively. For each $C\sb{M,T}$-expression e, $\vec e$ is its distinctly chosen representative in $U\sb{o},$ and $\lbrack\!\lbrack e\rbrack\!\rbrack$ is a constant $C\sb{o}$-term which names $\vec e.$ ;The goal is to find $\mu\sb*$ and $\tau\sb*,$ such that $\mu\sb*$ and $\tau\sb*$ plausibly and "self-referentially" approximate meaningfulness and truth respectively for any interpreted language represented by ${\cal T}\sb{\mu\sb*,\tau\sb*},$ by satisfying at least the following conditions. ; $\tau\sb*\subseteq\mu\sb*,$ and for each $C\sb{M,T}$-sentence $\sigma$ such that ${\cal T}\sb{\mu\sb*,\tau\sb*}\models M\lbrack\!\lbrack\sigma\rbrack\!\rbrack,$ $$\eqalign{&\ {\cal T}\sb{\mu\sb*,\tau\sb*} \models\sigma\Longleftrightarrow{\cal T}\sb{\mu\sb*,\tau\sb*}\models T\lbrack\!\lbrack\sigma\rbrack\!\rbrack,\ {\rm and}\cr&\ {\cal T}\sb{\mu\sb*,\tau\sb*}\models T\lbrack\!\lbrack\sigma\\leftrightarrow T\lbrack\!\lbrack\sigma\rbrack\!\rbrack\rbrack\!\rbrack.\cr}$$ ; There is a class of expression representatives $\mu\sp{D}\subseteq\mu\sb*$ containing every $C\sb{o}$-expression representative, such that the set $\tau\sp{D}=\mu\sp{D}\ \cap\ \tau\sb*$ itself satisfies the following properties. ;First, for each $\vec\sigma$ such that $\sigma$ is a $C\sb{M,T}$-sentence, if for all $\mu,\tau\subseteq U\sb{o}$ satisfying $\mu\supseteq\mu\sb*$ and $\tau\supseteq\tau\sp{D},$ it is the case that ${\cal T}\sb{\mu,\tau}\models\sigma,$ then $\vec\sigma\in\tau\sp{D}.$ ;Second, whenever $\vec\sigma\in\tau\sp{D},$ then also $\sp{\vec{\enspace}}\ \in\tau\sp{D}.$ ;Third, $\tau\sp{D}$ is "upwardly closed" with respect to the strong-Kleene rules for the truth-value evaluation of Boolean combinations of formulas. For example, for $C\sb{M,T}$-sentences $e\sb1$ and $e\sb2$: $$\eqalign{&\ \vec e\sb1\in\tau\sp{D}\Longleftrightarrow)\sp{\vec{\enspace}}\ \in\tau\sp{D}.\cr&\ {\rm If}\ \vec e\sb1\in\tau\sp{D}\ {\rm or}\ \vec e\sb2\in\tau\sp{D},\ {\rm then\ so\ is}\ \sp{\vec{\enspace}}\ \in\tau\sp{D}.\cr&\ {\rm If}\ \sp{\vec{\enspace}}\ \in\tau\sp{D}\ {\rm and}\ \sp{\vec{\enspace}}\ \in\tau\sp{D},\ {\rm then}\ )\sp{\vec{\enspace}}\ \in\tau\sp{D}.\cr}$$ ; For each $C\sb{M,T}$-expression e not involving T, ${\cal T}\sb{\mu\sb*,\tau\sb*}\models M\lbrack\!\lbrack e\rbrack\!\rbrack$; in particular, for any $C\sb{M,T}$-expression e whatsoever, ${\cal T}\sb{\mu\sb*,\tau\sb*}\models M\lbrack\!\lbrack\\neg M\lbrack\!\lbrack e\rbrack\!\rbrack\rbrack\!\rbrack.$ ; ;In this dissertation, it is shown for the first time that there are in fact $\mu\sb*$ and $\tau\sb*$ which simultaneously satisfy all three conditions , , and , even when the consequent of the Godel fixed point theorem must hold. (shrink)

In this important new text, Keith Lehrer introduces students to the major traditional and contemporary accounts of knowing. Beginning with the accepted definition of knowledge as justified true belief, Lehrer explores the truth, belief and justification conditions on the way to a thorough examination of foundation theories of knowledge, externalism and naturalized epistemologies, internalism and modern coherence theories as well as recent reliabilist and causal theories. Lehrer gives all views careful examination and concludes that external factors must be matched (...) by appropriate internal ones to yield knowledge. Readers of Professor Lehrer's earlier book _Knowledge_ will want to know that this text adopts the framework of that classic text. But _Theory of Knowledge_ is a completely rewritten and updated version of that book that has been simplified throughout for student use. (shrink)

In this paper I urge friends of truth-value gaps and truth-value gluts – proponents of paracomplete and paraconsistent logics – to consider theories not merely as sets of sentences, but as pairs of sets of sentences, or what I call ‘bitheories,’ which keep track not only of what holds according to the theory, but also what fails to hold according to the theory. I explain the connection between bitheories, sequents, and the speech acts of assertion and (...) denial. I illustrate the usefulness of bitheories by showing how they make available a technique for characterising different theories while abstracting away from logical vocabulary such as connectives or quanti- fiers, thereby making theoretical commitments independent of the choice of this or that particular non-classical logic. (shrink)

Questions concerning the proof-theoretic strength of classical versus nonclassical theories of truth have received some attention recently. A particularly convenient case study concerns classical and nonclassical axiomatizations of fixed-point semantics. It is known that nonclassical axiomatizations in four- or three-valued logics are substantially weaker than their classical counterparts. In this paper we consider the addition of a suitable conditional to First-Degree Entailment—a logic recently studied by Hannes Leitgeb under the label HYPE. We show in particular that, (...) by formulating the theory PKF over HYPE, one obtains a theory that is sound with respect to fixed-point models, while being proof-theoretically on a par with its classical counterpart KF. Moreover, we establish that also its schematic extension—in the sense of Feferman—is as strong as the schematic extension of KF, thus matching the strength of predicative analysis. (shrink)

In VAGUENESS AND DEGREES OF TRUTH, Nicholas Smith develops a new theory of vagueness: fuzzy plurivaluationism. -/- A predicate is said to be VAGUE if there is no sharply defined boundary between the things to which it applies and the things to which it does not apply. For example, 'heavy' is vague in a way that 'weighs over 20 kilograms' is not. A great many predicates -- both in everyday talk, and in a wide array of theoretical vocabularies, (...) from law to psychology to engineering -- are vague. -/- Smith argues, based on a detailed account of the defining features of vagueness, that an accurate theory of vagueness must involve the idea that truth comes in degrees. The core idea of degrees of truth is that while some sentences are true and some are false, others possess intermediate truth values: they are truer than the false sentences, but not as true as the true ones. Degree-theoretic treatments of vagueness have been proposed in the past, but all have encountered significant objections. In light of these, Smith develops a new type of degree theory. Its innovations include a definition of logical consequence that allows the derivation of a classical consequence relation from the degree-theoretic semantics, a unified account of degrees of belief and their relationships with degrees of truth and subjective probabilities, and the incorporation of semantic indeterminacy -- the view that vague statements need not have unique meanings -- into the degree-theoretic framework. -/- As well as being essential reading for those working on vagueness, Smith's book provides an excellent entry-point for newcomers to the area -- both from elsewhere in philosophy, and from computer science, logic and engineering. It contains a thorough introduction to existing theories of vagueness and to the requisite logical background. (shrink)

The paper offers a critical examination of a prominent, “quasi-deflationist” argument advanced in the contemporary debate on the semantic paradoxes against non-naive and non-transparent theories of truth. The argument claims that truth unrestrictedly fulfils certain expressive functions, and that its so doing requires the unrestricted validity of naivety and transparency principles. The paper criticises the quasi-deflationist argument by considering some kinds of cases in which transparency and naivety arguably fail. In some such cases truth still fulfils the (...) relevant expressive functions without being transparent or naive; in some other such cases, truth does not fulfil the relevant expressive functions and other conceptual resources must be called upon. Thus, in different ways, all such cases belie the quasi-deflationist argument’s insistence that naivety and transparency should be unrestrictedly valid for truth unrestrictedly to fulfil the relevant expressive functions. There might however be other reasons for solving the semantic paradoxes by revising classical logic, and the paper in effect closes by offering versions of the liar paradox that rely on compelling but opacity-friendly truth-theoretic principles. (shrink)

§1. Introduction. The problem raised by the liar paradox has long been an intriguing challenge for all those interested in the concept of truth. Many “solutions” have been proposed to solve or avoid the paradox, either prescribing some linguistical restriction, or giving up the classical true-false bivalence or assuming some kind of contextual dependence of truth, among other possibilities. We shall not discuss these different approaches to the subject in this paper, but we shall concentrate on a (...) kind of formal construction which was originated by Kripke's paper “Outline of a theory of truth” [11] and which, in different forms, reappears in later papers by various authors.The main idea can be presented as follows: assume a first order language ℒ containing, among other unspecified symbols, a predicate symbolTintended to represent the truth predicate for ℒ. Assume, also, a fixed modelM= 〈D, I〉 whereDcontains all sentences of ℒ andIinterprets all non-logical symbols of ℒ exceptTin the usual way. In general,Dmight contain many objects other than sentences of ℒ but as that would raise the problem of the meaning of sentences in whichTis applied to one of these objects, we shall assume that this is not the case. (shrink)