Dirk Greimann

Na sua resenha do meu artigo A Negação Fregeana do Número 2, Pedro Barbalho criticou a minha tentativa de mostrar que, dada a reconstrução da sintaxe e da semântica do sistema em Grundgesetze que apresentei num artigo anterior, a suposição de Frege de que “|Ø-- 2” é uma expressão bem-formada com um sentido e uma referência pode ser satisfatoriamente explicada. Pedro Barbalho oferece uma explicação alternativa que é sugerida pela tese Fregena no § 46 de Grundlagen de que uma afirmação sobre um número contém uma afirmação sobre um conceito. Nesta resposta, o meu objetivo é mostrar que esta estratégia para fazer sentido de “|Ø-- 2” não realmente funciona.

In his writings on the foundations of logic, Gottlob Frege, the father of modern logic, sketched a conception of truth that focuses on the following questions: What is the sense of the word "true"? Is truth a definable concept or a primitive one? What are the kinds of things of which truth is predicated? What is the role of the concept of truth in judgment, assertion and recognition? What is the logical category of truth? What is the significance of the concept of truth for science in general and for logic in particular? The present volume is dedicated to the interpretation, reconstruction and critical assessment of Frege's conception of truth. It is of interest to all those working on Frege, the history of logic and semantics, or theories of truth. The volume brings together nine original papers whose authors are all widely known to Frege scholars. The main topics are: the role of the concept of truth in Frege's system, the nature of the truth-values, the logical category of truth, the relationship between truth and judgment, and the conception of the truth-bearers.

Whereas the relationship between truth and propositional content has already been intensively investigated, there are only very few studies devoted to the task of illuminating the relationship between truth and illocutionary acts. This book fills that gap. This innovative collection addresses such themes as: the relation between the concept of truth and the success conditions of assertions and kindred speech acts the linguistic devices of expressing the truth of a proposition the relation between predication and truth.

In his logical foundation of arithmetic, Frege faced the problem that the semantic interpretation of his system does not determine the reference of the abstract terms completely. The contextual definition of number, for instance, does not decide whether the number 5 is identical to Julius Caesar. In a late writing, Quine claimed that the indeterminacy of reference established by Frege’s Caesar problem is a special case of the indeterminacy established by his proxy-function argument. The present paper aims to show that Frege’s Caesar problem does not really support the conclusions that Quine draws from the proxy-function argument. On the contrary, it reveals that Quine’s argument is a non sequitur: it does not establish that there are alternative interpretations of our terms that are equally correct, but only that these terms are ambiguous. The latter kind of referential indeterminacy implies that almost all sentences of our overall theory of the world are either false or neither true nor false, because they contain definite descriptions whose uniqueness presupposition is not fulfilled. The proxy-function argument must therefore be regarded as a reductio ad absurdum of Quine’s behaviorist premise that the reference of terms is determined only by our linguistic behavior.

In his late philosophy, Quine generalized the structuralist view in the philosophy of mathematics that mathematical theories are indifferent to the ontology we choose for them. According to his ‘global structuralism’, the choice of objects does not matter to any scientific theory. In the literature, this doctrine is mainly understood as an epistemological thesis claiming that the empirical evidence for a theory does not depend on the choice of its objects. The present paper proposes a new interpretation suggested by Quine’s recently published Kant Lectures from 1980 according to which his global structuralism is a semantic thesis that belongs to his theory of ontological reduction. It claims that a theory can always be reformulated in such a way that its truth does not presuppose the existence of the original objects, but only of some objects that can be considered as their proxies. Quine derives this claim from the principle of the semantic primacy of sentences, which is supposed to license the ontological reductions he uses to establish his global structuralism. It is argued that these reductions do not actually work because they do not account for some hidden ontological commitments that are not detected by his criterion of ontological commitment.

Frege hat über Jahrzehnte hinweg an einem Buch über die Grundlagen der Logik gearbeitet, dessen erster Teil folgenden Fragen gewidmet sein sollte: Ist Wahrheit definierbar oder ein „logisches Urelement“? Ist Wahrheit die Übereinstimmung eines inneren Bildes mit der Realität, oder ein Spezialfall der Beziehung zwischen dem Sinn eines Zeichens und seinem Bezug? Welchen Beitrag leistet der Sinn des Wortes ,wahr’ zu dem Sinn der Sätze, in denen es vorkommt? Sind die Wahrheitswerte – „das Wahre“ und „das Falsche“ – als Eigenschaften oder als Gegenstände aufzufassen? Gehört das, was wahr oder falsch ist, der Innenwelt an? Was ist eine Tatsache? Frege war jedoch weit davon entfernt, seine Konzeption der Wahrheit in die Form einer systematischen Theorie zu bringen. Sie besteht vielmehr aus einem losen und überaus komplexen Konglomerat wahrheitstheoretischer Doktrinen, die – für sich genommen – sehr unterschiedlichen und teilweise auch gegensätzlichen Richtungen der Wahrheitstheorie zuzuordnen sind. Aus diesen Gründen hat die Konzeption bisher wenig Beachtung gefunden; sie gilt als weitgehend konfus und inkohärent. Die vorliegende Studie versucht dagegen zu zeigen, daß sich die Konzeption bei genauerer Betrachtung als ein Ansatz von hoher Überzeugungskraft und systematischer Geschlossenheit entpuppt. Die exegetische Hauptthese ist, daß die Konzeption auf einem originellen Grundverständnis von Wahrheit basiert, das sich durch die Orientierung an der „behauptenden Kraft“ auszeichnet: Unter „Wahrheit“ versteht Frege das, was in der natürlichen Sprache durch die „Form des Behauptungssatzes“ ausgedrückt wird.

ABSTRACT In “Die Verneinung”, Frege discusses two types of negation, a semantic one and a pragmatic one. Semantic negation consists in the application of the logical function denoted by ‘it is false that p’ to a thought, and pragmatic negation in the act of asserting or judging a thought as false. According to the standard interpretation, Frege does not acknowledge pragmatic negation, because it is logically redundant. He therefore rejects the classical dualistic view that both truth and falsity are qualities of judgement and adopts instead the monistic view that to judge is always to recognize a thought as true. My aim in this paper is to show that this interpretation cannot be sustained. Though Frege does not endorse the classical view, he defends a dualistic conception that is characterized by the claim that judging is a binary operation that contains both the act of recognizing a thought as true and the act of rejecting the opposite thought as false. To make this interpretation plausible, Frege’s dualistic remarks on negation in three posthumous writings, which have received little attention so far, are analyzed in detail and their background is reconstructed. It is argued that Frege acknowledges negative judgements to account for the epistemic role of the act of judgement in the acquisition of knowledge. RESUMO Frege discute dois tipos de negação em “Die Verneinung” : uma semântica e uma pragmática. Negação semântica consiste na aplicação da função lógica denotada por ‘é falso que p’ para um pensamento, e negação pragmática no ato de afirmar ou julgar um pensamento como falso. De acordo com a interpretação padrão, Frege não reconhece a negação pragmática, porque ela é logicamente redundante. Assim, ele rejeita a visão dualística clássica de que tanto verdade quanto falsidade são qualidades de julgamento e, em vez disso, adota a visão monística de que julgar é sempre reconhecer um pensamento como verdade. Meu objetivo neste artigo é mostrar que tal interpretação não pode ser sustentada. Apesar de Frege não endossar a visão clássica, ele defende um conceito dualista que é caracterizado pela afirmação de que julgar é uma operação binária que contém tanto o ato de reconhecer um pensamento como verdade, quanto o ato de rejeitar o pensamento oposto como falso. Para tornar essa interpretação plausível, Frege faz observações dualísticas sobre a negação em três escritos póstumos, que têm recebido pouca atenção até o presente, são analisadas em detalhe e seu background é reconstruído. Argumenta-se que Frege reconhece o julgamento negativo para explicar o papel epistêmico do ato de julgar na aquisição de conhecimento.

According to the proximal theory of meaning, which is to be found in Quine’s early writings, meaning is determined completely by the correla-tion of sentences with sensory stimulations. Davidson tried to show that this theory is untenable because it leads to a radical form of skepticism. The present paper aims to show, first, that Davidson’s criticism is not sound, and, second, that nonetheless the proximal theory is untenable because it has a very similar and equally unacceptable consequence: it implies that the truth-value of ordinary sentences like ‘Snow is white’ is completely determined by the properties of the speaker, not by the prop-erties of the objects to which these sentences refer.

This paper aims to determine what kind of problem Frege's famous “Julius Caesar problem” is. whether it is to be understood as the metaphysical problem of determining what kind of things abstract objects like numbers or value‐courses are, or as the epistemological problem of providing a means of recognizing these objects as the same again, or as the logical problem of providing abstract sortal concepts with a sharp delimitation in order to fulfill the law of excluded middle, or as the semantic problem of fixing the referents of the corresponding abstract singular terms. It is argued that, for Frege, the Caesar problem is a bundle of related problems of which the semantic problem is the most basic one

Quine has persuasively shown that the empiricist "dogma of reductionism", which is the belief that each meaningfiil statement of science can be reduced to statements about immediate sense experience, must be abandoned. However, Quine's methodology of ontology seems to incorporate an analogous physicalistic dogma according to which the identity conditions of each scientifically respectable sort of abstract objects can be reduced to the identity conditions of physical objects. This paper aims to show that the latter dogma must be abandoned, too. In section 1, the reductionist methodology underlying Quine's prescript "No Entity without Identity" is reconstructed in detail. In section 2 and 3, this methodology is criticized on the ground that Quine's individuation of sets offendsagainst the reductive Criteria of adequacy for individuations that are presupposed by his criticism of the ontological recognition of intensional objects. Finally, in section 4 an alternative holistic conception of individuation is outlined.

According to Peter Aczel, the inconsistency of Frege’s system in Grundgesetze is due, not to the introduction of sets, as is usually thought, but to the introduction of the Horizontal. His argument is that the principles governing sets are intuitively correct and therefore consistent, while the scheme introducing the Horizontal amounts to an internal definition of truth conflicting with Tarski’s classic result on the undefinability of truth in the object language. The aim of this paper is to show that the Horizontal is innocent: Aczel’s diagnosis is based on a mistaken view of the structure underlying Frege’s ideal language

Quines Kritik an den grundlegenden semantischen Begriffen hat zwei wesentliche Prämissen: erstens daß die Linguistik als wissenschaftliche Disziplin der methodischen Restriktion unterstellt ist, empirisch sinnlose Hypothesen und Begriffe abzulehnen, und zweitens, daß die semantischen Begriffe tatsächlich empirisch sinnlos sind. Um die Überzeugungskraft der Ausführungen Quines untersuchen zu können, werden zunächst die verschiedenen Versionen von seiner Kritik analysiert, klar gegeneinander abgegerenzt und in die Form expliziter Argumentationen gebracht. Prämissen, die in die jeweiligen Versionen implizit eingehen, werden rekonstruiert und darauf hin untersucht, ob sie durch Quines Gesamtsystem gestützt werden, bzw. überhaupt mit ihm verträglich sind. Quines Kritik erfährt so eine rein immanente Kritik mit dem Ergebnis, daß es ihm nicht gelingt, zwingende Gründe für die Ablehnung der semantischen Begriffe anzuführen.

Der erste Teil des Aufsatzes untersucht den Inhalt der These. Im Zentrum steht dabei die Frage, was Frege unter,,Wahrheit" versteht. Das Ergebnis der Untersuchung ist, daß Freges Undefinierbarkeitsthese (entgegen der üblichen Auffassung) sich nicht auf den „Inhalt des Wortes,wahr'" (bzw. auf das Wahrheitsprädikat) bezieht, sondern auf „die Wahrheit, deren Anerkennung in der Form des Behauptungssatzes liegt" (bzw. auf den Urteilsstrich. Das Kernstück des zweiten Teils der Arbeit ist eine Rekonstruktion der Argumente Freges für die These in drei Versionen. Für die Rekonstruktion wird nicht (wie sonst üblich) Freges Redundanztheorie der Wahrheit herangezogen, sondern seine Urteilstheorie. Im dritten Teil schließlich wird die Frage behandelt, ob Freges These durch Tarskis Wahrheitsdefinitionen widerlegt ist.

Nach Auffassung von Quine ist der Realitätsbereich der Semantik auf den Bereich des beobachtbaren Sprachverhaltens beschränkt. Fragen der sprachlichen Bedeutung und sprachlichen Bezugs, die über das hinausgehen, was sich durch die Erforschung des öffentlich beobachtbaren Sprachverhalten herausbekommen lässt, sind dieser Auffassung nach keine "Tatsachenfragen", d.h. sie haben kein Fundament in der Realität. Die Arbeit verfolgt das Ziel, anhand des Aufbaus einer Theorie der "semantischen Verpflichtung" zu zeigen, dass Quines Beschränkung der semantischen Tatsachen nicht akzeptabel ist. Den Kern der Theorie bildet das folgende "Prinzip der semantischen Verpflichtung": Eine Gesamttheorie der Wirklichkeit ist aus Gründen der Kohärenz verpflichtet, diejenigen semantischen Strukturen ontologisch anzuerkennen, die vorausgesetzt werden müssen, um die Theorie formulieren zu können

It is commonly assumed that the conception of truth defended by Frege in his mature period is characterized by the view that truth is not the property denoted by the predicate 'is true', but the object named by true sentences. In the present paper, I wish to make plausible an alternative interpretation according to which Frege's conception is characterized by the view that truth is what is expressed in natural language by the "form of the assertoric sentence". So construed, truth is neither an object (like the True) nor a property (like the Bedeutung of the predicate 'is true') but something of a very special kind that belongs to the same logical category as the logical relations (like subsumption). The main argument justifying this interpretation is that Frege's explication of truth does not hold of the True, but only of truth, considered as what is expressed by the form of the assertoric sentence.