Marco Ruffino

This monograph offers a comprehensive study of contingent a priori truths. Building onto a theoretical framework developed by the philosopher and logician Saul Kripke, the author also presents a new approach to these truths. The first part of the book details the many theories on contingent a priori truths. The coverage examines the cases of Kripke and David Kaplan, Donnellan and the de re requirement, Evans and weak contingency, as well as Plantinga, Salmon, Soames, and the pseudo a priori. Overall, it provides a systematic discussion and critical review of all these many positions. Next, the author develops an alternative approach. His working hypothesis is that performative verbs must play a central role in Kripke's examples, even if they do not show up at the surface structure of the corresponding sentences. This opens up an entirely new way of looking at Kripke's cases and of treating them by exploring some aspects of the theory of illocutionary acts. His discussion also examines brute facts and institutional facts, indexicals and performatives, as well as Frege's theory of definitions. Providing an authoritative exploration into contingent a priori truths, this book will be of interest to students, academics, and researchers in philosophy and logic.

In the Tractatus Wittgenstein claims that a sentence expresses the same proposition in every possible world and, hence, which proposition is expressed cannot depend on how each world is. In this paper, I shall explore the interpretation of this thesis under the perspective of Stalnaker’s theory of assertions as the reduction of the context set, i.e., the set of possible worlds compatible with the information gathered at a conversation. In Stalnaker’s version, this principle follows from the explication of assertions as having the illocutionary point of excluding some possible worlds from the context set. If there is no unique instruction to exclude some worlds, then it is not clear which reduction is meant by the speaker. This might lead to a better understanding of Wittgenstein’s own version.

In this article the author discusses what seems to be a puzzle for Frege’s notion of singular senses, in particular senses of definite descriptions. These senses are supposed to be complete, but they are composed of the incomplete senses of conceptual terms. The author asks how the definite article transforms an unsaturated sense into a saturated one and reviews some attempted explanations in the literature. He argues that none of them is compatible with Frege’s views in semantics. Next, he discusses an alternative that Frege himself endorses and argues that it is also incompatible with his semantics. The author concludes that Frege has no coherent view on the senses of definite descriptions. If we assume that every name expresses a descriptive sense, then we must conclude that Frege has no coherent explanation for singular senses in general.

Logic and philosophy of logic have increasingly become areas of research and great interest in Latin America and Spain, where significant work has been done and continues to be done in both of these fields. The goal of this volume is to draw attention to this work through a collection of original and unpublished papers by specialists from Latin America and Spain. Some of the papers are of importance for set-theory and model theory. They cover topics such as the foundations of paraconsistency, the use of paraconsistent logic as a basis for set-theory, and the methodological aspects in both the justification of new axioms in set theory and the formalization of pre-theoretic notions. Other papers are related to epistemic logic. They deal with the issues of abduction and the choice of the simplest hypothesis, the definition of group probability, and the nature of explanation and understanding in such logic. There are also papers on logical paradoxes, the semantics of names (including fictional names), and the nature of relations.

Donnellan argues for a radical limitation of Kripke’s thesis concerning the possibility of contingent truths knowable a priori as a result of descriptive reference fixing for names. According to the former, in the absence of some form of acquaintance between the speaker and the object of knowledge, there can be no de re singular knowledge envisaged by Kripke. And in the presence of acquaintance, there can be no a priori knowledge. On the other hand, Jeshion argues that Donnellan’s main argument is fundamentally flawed. She explores a loophole intentionally left open by Donnellan to say that he has not ruled out an alternative explanation for the problem that motivates the revision of Kripke’s thesis. In this paper, I access Jeshion’s argument against Donnellan. As I intend to show, she does not fully appreciate a second loophole in Donnellan’s account that offers a more appropriate way of seeing Kripke’s examples.

We offer a novel picture of mathematical language from the perspective of speech act theory. There are distinct speech acts within mathematics, and, as we intend to show, distinct illocutionary force indicators as well. Even mathematics in its most formalized version cannot do without some such indicators. This goes against a certain orthodoxy both in contemporary philosophy of mathematics and in speech act theory. As we will comment, the recognition of distinct illocutionary acts within logic and mathematics and the incorporation of illocutionary force indicators in the formal language for both goes back to Frege’s conception of these topics. We are, therefore, going back to a Fregean perspective. This paper is part of a larger project of applying contemporary speech act theory to the scientific language of mathematics in order to uncover the varieties and regular combinations of illocutionary acts present in it. For reasons of space, we here concentrate only on assertive and declarative acts within mathematics, leaving the investigation of other kinds of acts for a future occasion.

My primary goal in this paper is to defend the plausibility of Kripke’s thesis that there are contingent a priori truths, and to fill out some gaps in Kripke’s own account of these truths. But the strategy here adopted is, to the best of my knowledge, still unexplored and different from the one adopted both by Kripke himself and by his critics. I first argue that Kripke’s examples of such truths can only be legitimate if seen as introduced by performative utterances sense). And, if this is so, we can apply the machinery of illocutionary act theory to these utterances to explain how one can have a priori knowledge of some contingent facts generated by the utterances themselves. I shall argue that the overall strategy can fill out two gaps in Kripke’s original account: first, we can explain the nature of the truth-makers of contingent a priori truths sense, broadly conceived) and, second, we can explain how contingent a priori knowledge can be transmitted from one speaker to another.

Logic and philosophy of logic have increasingly become areas of research and great interest in Latin America and Spain, where significant work has been done and continues to be done in both of these fields. The goal of this volume is to draw attention to this work through a collection of original and unpublished papers by specialists from Latin America and Spain. Some of the papers are of importance for set-theory and model theory. They cover topics such as the foundations of paraconsistency, the use of paraconsistent logic as a basis for set-theory, and the methodological aspects in both the justification of new axioms in set theory and the formalization of pre-theoretic notions. Other papers are related to epistemic logic. They deal with the issues of abduction and the choice of the simplest hypothesis, the definition of group probability, and the nature of explanation and understanding in such logic. There are also papers on logical paradoxes, the semantics of names, and the nature of relations. Max A. Freund is Professor of Logic and Philosophy at the University of Costa Rica and the National University of Costa Rica. He is co-author of the book Modal Logic its syntax and semantics, as well as the author of Judicial Logic, and of a forthcoming book The Logic of Sortals. Max Fernandez de Castro is Professor of Logic and Philosophy at the Autonomous Metropolitan University of Mexico. He is the author of the book Quine y la Ontologíaa and co-author of the books Lógica Matemática I: lógica proposicional, intuicionista y modal, Lógica Matemática II: clásica, intuicionista y modal, Teoría de Conjuntos, Lógica y Temas Afines I. Marco Ruffino is Professor of Philosophy at the University of Campinas and the editor of Manuscrito, the Brazilian international journal for Analytic Philosophy. He has many publications, in important philosophical journals, in the philosophy of language, of logic, and of mathematics; in the history of analytic philosophy, and on Frege and Wittgenstein.

In the dissertation I seek to clarify an aspect of Frege's thought that has been insufficiently explained in the literature, namely, his notion of logical object. It is well known that the core of Frege's philosophical enterprise up to Grundgesetze der Arithmetik was the reduction of arithmetic to logic. Since Frege regarded numbers as objects, logic must have an ontological basis, i.e., an adequate class of objects to which numbers are reducible. These objects are, for Frege, extensions of concepts and truth-values. ;In the dissertation I adduce some elements of Frege's philosophy that elucidate why he saw these as natural candidates for paradigmatic cases of logical objects. In particular, I argue that Frege could not have taken Hume's principle instead of Axiom V as a fundamental law of arithmetic. This would be inconsistent with his views on logical objects. First, I try to explain what are the general criteria for qualifying objects as logical, and why extensions of concepts have to be seen as the paradigmatic case of logical objects according to these criteria. There is, in my view, a connection between Frege's view on this topic and the famous thesis first formulated in ""Uber Begriff und Gegenstand " that "the concept horse is not a concept." ;Next, I examine Frege's introduction of truth-values as objects in his writings from 1891-92. As I shall argue, Frege's ontologization of truth-values is basically motivated and justified by the technical advantages that this step brought for the formalism of Grundgesetze der Arithmetik. ;Finally, I examine Frege's arguments in section 10 of Grundgesetze der Arithmetik, since this is the place in Frege's writings where extensions and truth-values are identified. I argue that Frege did not mean to employ a generalized version of the context principle in this section. Moreover, I argue that there is no incompatibility between Frege's procedure in this section and his realism regarding mathematical entities

Matthias Schirn has argued on a number of occasions against the interpretation of Frege's ``objects of a quite special kind'' (i.e., the objects referred to by names like `the concept F') as extensions of concepts. According to Schirn, not only are these objects not extensions, but also the idea that `the concept F' refers to objects leads to some conclusions that are counter-intuitive and incompatible with Frege's thought. In this paper, I challenge Schirn's conclusion: I want to try and argue that the assumption that `the concept F' refers to the extension of F is entirely consistent with Frege's broader views on logic and language. I shall examine each of Schirn's main arguments and show that they do not support his claim.

In this paper I argue indirectly for Frege's semantics, in particular for his conception of propositions, by reviewing some difficulties faced by one of the main contemporary alternative approaches, i.e., the direct reference theory. While Frege's semantics can yield an explanation of cognitive value and belief-preservation, the alternative approach seems to run into trouble here. I shall also briefly consider the question of whether epistemic issues should be of any concern for semantics, i.e., whether the feature mentioned above should really be regarded as an advantage of Frege's theory.

In this paper I discuss Chateaubriand’s notion of senses. His notions retains the spirit of the original Fregean notion, but differ from it in some fundamental ways. I compare both notions, especially concerning the issue of indirect reference, and also concerning their explanatory power in epistemic matters. Finally, I raise some worries concerning the semantic role played by Chateaubriand’s senses, as well as the notion of judgment that his notion of thoughts seems to imply.Neste artigo, discuto a noção de sentido de Chateaubriand. Sua noção retém o espírito da noção Fregeana original, mas difere da mesma em alguns aspectos fundamentais. Eu comparo ambas as noções, especialmente no que diz respeito à questão da referência indireta, e também no que concerne ao seu poder explicativo em questões epistêmicas. Por fim, levanto algumas preocupações sobre o papel semântico desempenhado pelos sentidos de Chateaubriand, bem como a forma dos juízos que a sua noção de pensamento implica

The purpose of this paper is to discuss Frege’s view on vagueness, and to draw some relevant consequences of it. By examining what exactly Frege has in mind each time he complains about vagueness and advocates the sharpness requirement, I argue that he shows preoccupation with different kinds of vagueness in different periods of his thought. I also discuss the scope of the sharpness requirement, and argue that it is intended as applying primarily to mathematics and logic. Finally, I try and argue that some of Frege’s remarks on incomplete functions suggest a view that is close in spirit to the contemporary supervaluationist approach to vagueness

In this paper, I seek to clarify an aspect of Frege's thought that has been only insufficiently explained in the literature, namely, his notion of logical objects. I adduce some elements of Frege's philosophy that elucidate why he saw extensions as natural candidates for paradigmatic cases of logical objects. Moreover, I argue (against the suggestion of some contemporary scholars, in particular, Wright and Boolos) that Frege could not have taken Hume's Principle instead of Axiom V as a fundamental law of arithmetic. This would be inconsistent with his views on logical objects. Finally, I shall argue that there is a connection between Frege's view on this topic and the famous thesis first formulated in ‘Über Begriff und Gegenstand’ that ‘the concept horse is not a concept’. As far as I know, no due attention has been given to this connection in the scholarly literature so far.