German: Unter den nichtlogischen Konstanten der Wissenschaftssprache werden zwei Arten unterschieden, die Beobachtungsterme (z. B. « blau ») und die theoretischen Terme (z. B. « elektrisches Feld »). Die letzteren werden nicht durch Definitionen eingeführt, sondern durch Postulate zweier Arten, nämlich theoretische Postulate, zum Beispiel Grundgesetze der Physik, und Korrespondenzpostulate, die die theoretischen Terme mit Beobachtungstermen verbinden. Wie schon Hilbert gezeigt hat, können in dieser Weise sowohl die Mathematik als auch die theoretische Physik als ungedeutete Kalküle aufgestellt werden. Es wird (...) hier kurz erklärt, dass durch diesen Aufbau auch den mathematischen Termen eine Bedeutung (in einem weiteren Sinne) beigelegt wird. Die theoretischen Terme erhalten durch die Korrespondenzpostulate wenigstens eine unvollständige Deutung. Es wird gezeigt, wie die Unterscheidung von analytischen und synthetischen Sätzen auch für die theoretische Sprache definiert werden kann. -/- English: Among the non‐logical constants of the language of science two kinds are distinguished, the observation terms (e.g., « blue ») and the theoretical terms (e.g., « electric field »). The latter terms are introduced, not by definitions, but by postulates of two kinds, theoretical postulates, e.g., basic laws of physics, and correspondence postulates which connect the theoretical terms with observation terms. As Hilbert has explained, both mathematics and theoretical physics can in this way be constructed in the form of uninterpreted calculi. It is here briefly indicated that by this method of construction also the mathematical terms have meanings (in a wider sense) assigned to them. The theoretical terms obtain at least an incomplete interpretation by means of the correspondence postulates. It is shown how the distinction between analytic and synthetic sentences can be defined also for the theoretical language. (shrink)

A comprehensive, systematic, and historical collection of essays on Rudolf Carnap's philosophy and legacy, written by leading international experts. This volume provides a redressing of Carnap's place in the history of analytic philosophy, through his approach to metaphysics, values, politics, epistemology and philosophy of science.

Carnap and Quine first met in the 1932-33 academic year, when the latter, fresh out of graduate school, visited the key centers of mathematical logic in Europe. In the months that Carnap was finishing his Logische Syntax der Sprache, Quine spent five weeks in Prague, where they discussed the manuscript “as it issued from Ina Carnap’s typewriter”. The philosophical friendship that emerged in these weeks would have a tremendous impact on the course of analytic philosophy. Not only (...) did the meetings effectively turn Quine into Carnap's disciple, they also paved the way for their seminal debates about meaning, language, and ontology---the very discussions that would change the course of analytic philosophy in the decades after the Second World War. -/- Yet surprisingly little is known about these first meetings. Although Quine has often acknowledged the impact of his Prague visit, there appears to be little information about these first encounters, except for the fact that the Quines “were overwhelmed by the kindness of the Carnaps” and that it was Quine’s “most notable experience of being intellectually fired by a living teacher”. Neither their correspondence nor their autobiographies offer a detailed account of these meetings. In this paper, I shed new light on Carnap’s and Quine’s first encounters by examining a set of previously unexplored material from their personal and academic archives. Why did Quine decide to visit Carnap? What did they discuss? And in what ways did the meetings affect Quine’s philosophical development? In what follows, I address these questions by means of a detailed reconstruction of Quine’s year in Europe based on a range of letters, notes, and reports from the early 1930s. (shrink)

The failed criterion of logical truth proposed by Carnap in the Logical Syntax of Language was based on the determinateness of all logical and mathematical statements. It is related to a conception which is independent of the specifics of the system of the Syntax, hints of which occur elsewhere in Carnap’s writings, and those of others. What is essential is the idea that the logical terms are invariant under reinterpretation of the empirical terms, and are therefore semantically determinate. (...) A certain objection to Carnap’s version of the invariance conception has been repeated several times in the literature. It is based on Gödel incompleteness, which is puzzling, since Carnap’s Syntax is otherwise quite careful to take account of Gödel. We show here that, in fact, the objection is invalid and is based on a confusion about determinacy. Sorting this out is worthwhile not only for the purpose of better understanding Carnap’s thinking in the Syntax, though. The invariance conception is also related to recent work in the philosophy of logic regarding “logicality”—the characterization of logical concepts—following a proposal of Tarski’s. It is even connected to some very recent developments in the foundations of mathematics. (shrink)

Moritz Schlick, Rudolf Carnap and Herbert Feig are the most prominent of the positivists to formulate views on the mind-body problem (aside from Hempel’s one-off treatment in 1935). While their views differed from each other and changed over time they were all committed to some form of scientific physicalism, though a linguistic or conceptual rather than ontological form of it. In focus here are their views during the heyday of logical positivism and its immediate aftermath, though some initial scene-setting (...) of Schlick’s and Carnap’s pre-positivist views will help to understand the final opposing positions of Carnap and Feigl. (shrink)

In Meaning and Necessity (1947/1950), Carnap advances an intensional semantic framework on which modal claims are true in virtue of semantical rules alone, and so are a priori. In 'Empiricism, Semantics, and Ontology' (1950), Carnap advances an epistemic-ontological framework on which metaphysical claims are either trivial or meaningless, since lacking any means of substantive confirmation. Carnap carried out these projects two decades before Kripke influentially argued, in Naming and Necessity (1972/1980), that some modal claims are true a (...) posteriori. How should a neo-Carnapian respond to Kripke's results? Some (notably, Chalmers and Jackson, in their 2001) have suggested that an extension of intensional semantics along lines of "epistemic two-dimensionalism" can accommodate Kripke's results while largely preserving commitment to the semantics-based a priority of modal claims. Here we consider how best to implement this suggestion, and how the resulting semantics fits with Carnap's second project. We find that the most promising (and most Carnapian!) post-Kripke version of Carnap’s semantics---abductive two-dimensionalism---presupposes an epistemology which undermines Carnap's metaphysical anti-realism. (shrink)

Als Wissenschaftslogik bezeichnet Carnap jene Disziplin, welche die Nachfolge der traditionellen Philosophie im 20. Jahrhundert antreten sollte. Den zentralen Bezugspunkt von Carnaps wissenschaftslogischen Arbeiten bildet die von Frege und Russell entwickelte mathematische Logik. Dies gilt auch für die Zweistufenkonzeption, mit der Carnap ein allgemeines Schema zur Analyse der Bedeutung von Begriffen nichtmathematischer Theorien entwirft. Dabei wird die Abhängigkeit der begrifflichen Bedeutung von den Aussagen der jeweiligen Theorie explizit anerkannt, was eine Überwindung der Dogmen des Empirismus innerhalb des Logischen (...) Empirismus einschlieβt. Allerdings geht Carnap in seinen Arbeiten zur Semantik formaler Sprachen auf die spezifischen Eigenschaften von theoretischen Termen nicht ein, so daβ die Überwindung der Dogmen des Empirismus unvollständig bleibt. Darauf gründet sich die wesentliche Aufgabe der vorliegenden Untersuchung, welche darin besteht, die Deutung von theoretischen Termen durch Postulate im Rahmen der mathematischen Logik exakt zu beschreiben. (shrink)

Rudolf Carnap’s principle of tolerance states that there is no need to justify the adoption of a logic by philosophical means. Carnap uses the freedom provided by this principle in his philosophy of mathematics: he wants to capture the idea that mathematical truth is a matter of linguistic rules by relying on a strong metalanguage with infinitary inference rules. In this paper, I give a new interpretation of an argument by E. W. Beth, which shows that the principle (...) of tolerance does not suffice to remove all obstacles to the employment of infinitary rules. (shrink)

Many who take a dismissive attitude towards metaphysics trace their view back to Carnap’s ‘Empiricism, Semantics and Ontology’. But the reason Carnap takes a dismissive attitude to metaphysics is a matter of controversy. I will argue that no reason is given in ‘Empiricism, Semantics and Ontology’, and this is because his reason for rejecting metaphysical debates was given in ‘Pseudo-Problems in Philosophy’. The argument there assumes verificationism, but I will argue that his argument survives the rejection of verificationism. (...) The root of his argument is the claim that metaphysical statements cannot be justified; the point is epistemic, not semantic. I will argue that this remains a powerful challenge to metaphysics that has yet to be adequately answered. (shrink)

This entry reviews Rudolf Carnap's philosophical views on the quantum mechanics of his time. It also offers some thoughts on how Carnap might have reacted to some recent developments in the foundations of quantum mechanics.

Forthcoming in Darren Bradley (ed.), Carnap and Contemporary Philosophy. -/- This paper is centered on Carnap’s views on rationality. More specifically, much of the focus is on a puzzle regarding Carnap’s view on rationality that Florian Steinberger has recently discussed. Not only is Steinberger’s discussion of significant intrinsic interest: his discussion also raises general questions about Carnap interpretation. As I have discussed in earlier work, there are two very different ways of interpreting Carnap’s talk of (...) “frameworks” – and, relatedly, different ways of interpreting Carnap’s principle of tolerance. Carnap can be interpreted as either a relativist or as what I call a language pluralist. Steinberger’s puzzle arises given the relativist interpretation; I believe the language pluralist interpretation is correct. Most of the discussion will concern the correct interpretation of Carnap, and what this means for Steinberger’s puzzle. While I will not here mount a full defense of the language pluralist interpretation, I will pause to discuss Vera Flocke’s recent criticism of it. Towards the end, I will describe a puzzle regarding rationality different from Steinberger’s. The puzzle that I describe does arise already for the language pluralist. (shrink)

During the academic year 1940-1941, several giants of analytic philosophy congregated at Harvard, holding regular private meetings, with Carnap, Tarski, and Quine. Carnap, Tarski, and Quine at Harvard allows the reader to act as a fly on the wall for their conversations. Carnap took detailed notes during his year at Harvard. This book includes both a German transcription of these shorthand notes and an English translation in the appendix section. Carnap’s notes cover a wide range of (...) topics, but surprisingly, the most prominent question is: If the number of physical items in the universe is finite, what form should scientific discourse take? This question is closely connected to an abiding philosophical problem: What is the relationship between the logico-mathematical realm and the material realm? Carnap, Tarski, and Quine’s attempts to answer this question involve issues central to philosophy today.This book focuses on three such issues: nominalism, the unity of science, and analyticity. In short, the book reconstructs the lines of argument represented in these Harvard discussions, discusses their historical significance (especially Quine’s break from Carnap), and relates them when possible to contemporary treatments of these issues. (shrink)

Kant's question 'How are synthetic judgments a priori possible?' pre- cipitated the Critique of Pure Reason. Question and answer notwith- standing, Mill and others persisted in doubting that such judgments were possible at all. At length some of Kant's own clearest purported.

Graham and Maitzen think my CORNEA principle is in trouble because it entails “intolerable violations of closure under known entailment.” I argue that the trouble arises from current befuddlement about closure itself, and that a distinction drawn by Rudolph Carnap, suitably extended, shows how closure, when properly understood, works in tandem with CORNEA. CORNEA does not obey Closure because it shouldn’t: it applies to “dynamic” epistemic operators, whereas closure principles hold only for “static” ones. What the authors see as (...) an intolerable vice of CORNEA is actually a virtue, helping us see what closure principles should—and shouldn’t—themselves be about. (shrink)

Rudolf Carnap and W. V. Quine, two of the twentieth century's most important philosophers, corresponded at length—and over a long period of time—on matters personal, professional, and philosophical. Their friendship encompassed issues and disagreements that go to the heart of contemporary philosophic discussions. Carnap was a founder and leader of the logical positivist school. The younger Quine began as his staunch admirer but diverged from him increasingly over questions in the analysis of meaning and the justification of belief. (...) That they remained close, relishing their differences through years of correspondence, shows their stature both as thinkers and as friends. The letters are presented here, in full, for the first time. The substantial introduction by Richard Creath offers a lively overview of Carnap's and Quine's careers and backgrounds, allowing the nonspecialist to see their writings in historical and intellectual perspective. Creath also provides a judicious analysis of the philosophical divide between them, showing how deep the issues cut into the discipline, and how to a large extent they remain unresolved. (shrink)

In this paper, I defend Rudolf Carnap's Principle of Tolerance from an accusation, due to Michael Friedman, that it is self-defeating by prejudicing any debate towards the logically stronger theory. In particular, Friedman attempts to show that Carnap's reconstruction of the debate between classicists and intuitionists over the foundations of mathematics in his book The Logical Syntax of Language, is biased towards the classical standpoint since the metalanguage he constructs to adjudicate between the rival positions is fully classical. (...) I argue that this criticism is mistaken on two counts: (1) it fails to fully appreciate the freedom with regard to the construction of linguistic frameworks that Carnap intended his Principle to embody, and (2) Friedman's objection underestimates the extent to which the evaluation of a framework is task-relative. I conclude that Tolerance is not self-undermining in the way that Friedman claims it is. While this is a restricted conclusion -- and is not a vindication of Carnap's views on logic and mathematics tout court -- it nonetheless suggests that his tolerant perspective has been dismissed too quickly, even by his supporters. (shrink)

My focus here will be Rudolf Carnap’s views on ontology, as these are presented in the seminal “Empiricism, Semantics and Ontology” (1950). I will first describe how I think Carnap’s distinction between external and internal questions is best understood. Then I will turn to broader issues regarding Carnap’s views on ontology. With certain reservations, I will ascribe to Carnap an ontological pluralist position roughly similar to the positions of Eli Hirsch and the later Hilary Putnam. Then (...) I turn to some interrelated arguments against the pluralist view. The arguments are not demonstrative. Some possible escape routes for the pluralist are outlined. But I think the arguments constitute a formidable challenge. There should be serious doubt as to whether the pluralist view, as it emerges after discussion of these arguments, will be worth defending. Moreover, there is an alternative ontological view which equally well subserves the motivations underlying ontological pluralism. (shrink)

The purpose of this article is to respond to Thomas Uebel’s criticisms of my comments regarding the current revisionism of Carnap’s work and its relations to Kuhn. I begin by pointing out some misunderstandings in the interpretation of my article. I then discuss some aspects related to Carnap’s view of the history of science. First, I emphasize that it was not due to a supposed affinity between Kuhn’s conceptions and those of logical positivists that Kuhn was invited to (...) write the monograph on the history of science for the Encyclopedia. Three other authors had been invited first, including George Sarton whose conception was entirely different from Kuhn’s. In addition, I try to show that Carnap attributes little importance to the history of science. He seldom refers to it and, when he does, he clearly defends a Whig or an ‘old’ historiography of science, to which Kuhn opposes his “new historiography of science”. It is argued that this raises serious difficulties for those, like Uebel, who hold the view that Carnap includes the historical or the social within the rational. (shrink)

This book is a major contribution to the history of analytic philosophy in general and of logical positivism in particular. It provides the first detailed and comprehensive study of Rudolf Carnap, one of the most influential figures in twentieth-century philosophy. The focus of the book is Carnap's first major work: Der logische Aufbau der Welt. It reveals tensions within the context of German epistemology and philosophy of science in the early twentieth century. Alan Richardson argues that Carnap's (...) move to philosophy of science in the 1930s was largely an attempt to dissolve the tension in his early epistemology. This book fills a significant gap in the literature on the history of twentieth-century philosophy. It will be of particular importance to historians of analytic philosophy, philosophers of science, and historians of science. (shrink)

The first part of this entry details what is known about the personal encounters between Rudolf Carnap and Edmund Husserl. The second part looks at all the places in Carnap’s works where Husserl is cited.

Does Carnap’s treatment of philosophical questions about existence, such as “Are there numbers?” and “Are there physical objects?”, depend on his analytic–synthetic distinction? If so, in what way? I answer these questions by clarifying, defending, and developing the reading of Carnap’s paper “Empiricism, Semantics, and Ontology” that W. V. Quine proposes, with little justification or explanation, in his paper “On Carnap’s Views on Ontology”. The primary methodological value of studying Quine’s reading of “Empiricism, Semantics, and Ontology” is (...) that it prompts us to look for, and helps us to see the significance of, passages by Carnap that reveal the logical foundations of his views on ontology. Guided in this way by Quine’s reading, I show that (1) in “Empiricism, Semantics, and Ontology” Carnap’s preferred treatment of philosophical questions relies on paraphrasing them so that their answers are immediately obvious elementary logical truths, and are therefore, by his standards, trivially analytic; and (2) in its most general form, Carnap’s treatment of philosophical questions about existence depends on his controversial view that the analytic truths of a language L may include sentences that are not elementary logical truths, but that are nevertheless, by Carnap’s standards, analytic-in-L simply because we have stipulated that they are to be among the “meaning postulates” of L. (shrink)

This article investigates the various ways in which Rudolf Carnap incorporated contemporary epistemological problems concerning the Geisteswissenschaften in Der logische Aufbau der Welt. I argue that Carnap defends a nonreductive incorporation of the Geisteswissenschaften within the unity of science. To this end Carnap aims to solve the problem of individuality, which was the focus of attention for important philosophers of the Geisteswissenschaften such as Wilhelm Dilthey, Heinrich Rickert, and Wilhelm Windelband. At the same time, Carnap argues (...) that his constitutional method, which transforms cultural objects into psychological or physical objects, does not imply a loss of autonomy for the Geisteswissenschaften. Besides this defense of autonomy, Carnap incorporates several central notions of the contemporary theory of the Geisteswissenschaften into his theory of the Aufbau: cultural manifestation, the phenomenology of cultural experience, and the method of Verstehen. (shrink)

Do numbers exist? Carnap (1956 [1950]) famously argues that this question can be understood in an “internal” and in an “external” sense, and calls “external” questions “non-cognitive”. Carnap also says that external questions are raised “only by philosophers” (p. 207), which means that, in his view, philosophers raise ”non-cognitive” questions. However, it is not clear how the internal/external distinction and Carnap’s related views about philosophy should be understood. This paper provides a new interpretation. I draw attention to (...) Carnap’s distinction between purely external statements, which are independent from all frameworks, and pragmatic external statements, which concern which framework one should adopt, and argue that the latter express noncognitive mental states. Specifically, I argue that “frameworks” are systems of rules for the assessment of statements, which are utterances of ordinary language sentences. Pragmatic external statements express noncognitive dispositions to follow only certain rules of assessment. For instance, “numbers exist” understood as a pragmatic external statement expresses a noncognitive disposition to use only rules of assessment according to which numbers do exist. Carnap can thereby be understood as proposing a distinctive form of noncognitivism about ontology that is in some respects analogous to norm-expressivism in metaethics. (shrink)

In this paper, I will offer a novel perspective on Carnapian explication, understanding it as a philosophical analogue of the transfer principle methodology that originated in nineteenth-century projective geometry. Building upon the historical influence that projective geometry exerted on Carnap’s philosophy, I will show how explication can be modeled as a kind of transfer principle that connects, relative to a given task and normatively constrained by the desiderata chosen by the explicators, the functional properties of concepts belonging to different (...) conceptual frameworks. Moreover, I will demonstrate how, in light of this characterization, we can better appreciate the evolution of Carnap’s metaphilosophy. (shrink)

Rudolf Carnap delivered the hitherto unpublished lecture ‘Theoretical Concepts in Science’ at the meeting of the American Philosophical Association, Pacific Division, at Santa Barbara, California, on 29 December 1959. It was part of a symposium on ‘Carnap’s views on Theoretical Concepts in Science’. In the bibliography that appears in the end of the volume, ‘The Philosophy of Rudolf Carnap’, edited by Paul Arthur Schilpp, a revised version of this address appears to be among Carnap’s forthcoming papers. (...) But although Carnap started to revise it, he never finished the revision,1 and never published the unrevised transcript. Perhaps this is because variants of the approach to theoretical concepts presented for the first time in the Santa Barbara lecture have appeared in other papers of his (cf. the editorial footnotes in Carnap’s lecture). Still, I think, the Santa Barbara address is a little philosophical gem that needs to see the light of day. The document that follows is the unrevised transcript of Carnap’s lecture.2 Its style, then, is that of an oral presentation. I decided to leave it as it is, making only very minor stylistic changes—which, except those related to punctuation, are indicated by curly brackets.3 I think that reading this lecture is a rewarding experience, punctuated as the lecture is with odd remarks and autobiographical points. One can almost envisage.. (shrink)

Carnap’s search for a criterion of empirical significance is usually considered a failure. I argue that the results from two out of his three different approaches are at the very least problematic, but that one approach led to success. Carnap’s criterion of translatability into logical syntax is too vague to allow for definite results. His criteria for terms—introducibility by chains of reduction sentences and his criterion from “The Methodological Character of Theoretical Concepts”—are almost trivial and have no clear (...) relation to the empirical significance of sentences. However, his criteria for sentences—translatability, verifiability, falsifiability, confirmability—are usable, and under the assumptions needed for the Carnap sentence approach, verifiability, falsifiability, and translatability become equivalent. As a result of the Carnap sentence approach, metaphysics is rendered analytic. (shrink)

Steve Awodey and A. W. Carus. How Carnap Could Have Replied to Gödel.

Carnap's ideal of explication has become a key concept in analytic philosophy and the basis of a method of analysis which may be considered as an alternative to various forms of naturalism, including Quine's conception of a naturalized epistemology. More recently, new light has been shed on this aspect of the classical Carnap-Quine debate by contemporary philosophers. Whereas Michael Friedman articulated a notion of relativized a priori which owes much to Carnap's internal/external distinction, André Carus attempted to (...) restate Carnap's ideal of explication in a way that bridges the gap between conceptual engineering and naturalism. On the other hand, Mark Wilson argued that concepts develop in unpredictable ways and cannot be planned in the way classical analytic philosophy has assumed from Frege and Russell onwards. This book consists of a series of defences as well as critiques of Carnap's programme, setting it in its historical context, discussing specific cases of explications, and enriching the on-going debate on conceptual engineering and naturalism in analytic philosophy.Carnap's ideal of explication has become a key concept in analytic philosophy and the basis of a method of analysis which may be considered as an alternative to various forms of naturalism, including Quine's conception of a naturalized epistemology. More recently, new light has been shed on this aspect of the classical Carnap-Quine debate by contemporary philosophers. Whereas Michael Friedman articulated a notion of relativized a priori which owes much to Carnap's internal/external distinction, André Carus attempted to restate Carnap's ideal of explication in a way that bridges the gap between conceptual engineering and naturalism. On the other hand, Mark Wilson argued that concepts develop in unpredictable ways and cannot be planned in the way classical analytic philosophy has assumed from Frege and Russell onwards. This book consists of a series of defences as well as critiques of Carnap's programme, setting it in its historical context, discussing specific cases of explications, and enriching the on-going debate on conceptual engineering and naturalism in analytic philosophy. (shrink)

The influential proposal that the analytical component of a theory is captured by its ‘Carnap sentence’ is critically scrutinized. A counterexample which makes the suggestion problematic is presented.

In an unpublished speech from 1991, David Lewis told his audience that he counted ‘the metaphysician Carnap ’ amongst his historical ancestors. Here I provide a novel interpretation of the Aufbau that allows us to make sense of Lewis’s claim. Drawing upon Lewis’s correspondence, I argue it was the Carnap of the Aufbau whom Lewis read as a metaphysician, because Carnap’s appeal to the notion of founded relations in the Aufbau echoes Lewis’s own appeal to the metaphysics (...) of natural properties. I further maintain that Lewis was right to read Carnap this way and that the notion of a founded relation has a legitimate claim to be both logical and metaphysical. I also argue that Carnap’s initial response to Goodman’s puzzle about ‘grue’ relies upon a metaphysics of simple properties which also prefigures Lewis’s own response to Goodman invoking natural properties. (shrink)

Carnap's theory of descriptions was restricted in two ways. First, the descriptive conditions had to be non-modal. Second, only primitive predicates or the identity predicate could be used to predicate something of the descriptum . The motivating reasons for these two restrictions that can be found in the literature will be critically discussed. Both restrictions can be relaxed, but Carnap's theory can still be blamed for not dealing adequately with improper descriptions.

Difficulties and ambiguities of Carnap’s conception of logic and mathematics are the main target of Gödel’s analysis in his famous drafts of “Is mathematics Syntax of Language?”. In a recent article, Gregory Lavers discusses two main recent dismissive analyses of Gödel’s drafts, concluding at a defense of Gödel’s arguments against Carnap’s position in the 1930. Lavers partially integrates in his examination an argument that I presented in a paper published in 2003. Yet, there are three important differences between (...) my understanding of Gödel’s argument and Lavers’s interpretation of it. These differences concern the appreciation of (a) Gödel’s strategy of using, in any critical examination of his opponents, only arguments that can be accepted by them; (b) Gödel’s analysis of Carnap’s position in the 1950s; (c) Gödel’s understanding of Carnap’s philosophical project. The paper aims to argue that, contrary to Lavers’s opinion, Gödel takes seriously the details of Carnap’s original conception and does not overlook the novelty of its solutions in the 1930s and 1950s. In particular, the comparison between Gödel’s arguments in the Gibbs lecture of 1951 and in version III of his draft of ‘Is mathematics Syntax of Language?’ shows how Gödel had in 1953–55 a careful concern with Carnap’s philosophical project of LSL. (shrink)

History of analytic philosophy has been an active, going concern within analytic philosophy for decades — one can scarcely imagine analytic philosophy being continued with some serious attention paid to the work of founders such as Gottlob Frege, Bertrand Russell, and Ludwig Wittgenstein. History of philosophy of science has become an explicit part of the philosophical agenda in the past quarter century or so. These areas of research importantly overlap — logical empiricism, in particular, was an episode in both histories. (...) One might be forgiven for thinking, given all this, that the question of the relations of analytic philosophy to philosophy of science in the twentieth century would have been importantly thematized in both sorts of history and that the historical relations between analytic philosophy and philosophy of science would be, by now, a well-tilled field. (shrink)

The waning popularity of logical empiricism and the supposed discovery of insurmountable technical difficulties led most philosophers to abandon the project to formulate a formal criterion of empirical significance. Such a criterion would delineate claims that observation can confirm or disconfirm from those it cannot. Although early criteria were clearly inadequate, criticisms made of later, more sophisticated criteria were often indefensible or easily answered. Most importantly, Carnap’s last criterion was seriously misinterpreted and an amended version of it remains tenable.

Livre fondateur de R. Carnap, "Der logische Aufbau der Welt" (1928) est une oeuvre philosophique allemande centrale du XXe siècle.Cet ouvrage veut montrer l'actualité de l'"Aufbau" tout en présentant la logique de pensée de Carnap et ses conséquences philosophiques.

A definition of a property P is impredicative if it quantifies over a domain to which P belongs. Due to influential arguments by Ramsey and Gödel, impredicative mathematics is often thought to possess special metaphysical commitments. It seems that an impredicative definition of a property P does not have the intended meaning unless P already exists, suggesting that the existence of P cannot depend on its explicit definition. Carnap (1937 [1934], p. 164) argues, however, that accepting impredicative definitions amounts (...) to choosing a "form of language" and is free from metaphysical implications. This paper explains this view in its historical context. I discuss the development of Carnap’s thought on the foundations of mathematics from the mid-1920s to the mid-1930s, concluding with an account of Carnap’s (1937 [1934]) non-Platonistic defense of impredicativity. This discussion is also important for understanding Carnap’s influential views on ontology more generally, since Carnap’s (1937 [1934]) view, according to which accepting impredicative definitions amounts to choosing a "form of language", is an early precursor of the view Carnap presents in "Empiricism, Semantics and Ontology" (1956 [1950]), according to which referring to abstract entities amounts to accepting a "linguistic framework". (shrink)

We take Carnap’s problem to be to what extent standard consequence relations in various formal languages fix the meaning of their logical vocabulary, alone or together with additional constraints on the form of the semantics. This paper studies Carnap’s problem for basic modal logic. Setting the stage, we show that neighborhood semantics is the most general form of compositional possible worlds semantics, and proceed to ask which standard modal logics (if any) constrain the box operator to be interpreted (...) as in relational Kripke semantics. Except when restricted to finite domains, no modal logic characterizes all the Kripkean interpretation of P. Moreover, we show that, in contrast with the case of first-order logic, the obvious requirement of permutation invariance is not adequate in the modal case. After pointing out some known facts about modal logics that nevertheless force the Kripkean interpretation, we focus on another feature often taken to embody the gist of modal logic: locality. We show that invariance under point-generated subframes (properly defined) does single out the Kripkean interpretations, but only among topological interpretations, not in general. Finally, we define a notion of bisimulation invariance — another aspect of locality — that, together with a reasonable closure condition, gives the desired general result. Along the way, we propose a new perspective on normal neighborhood frames as filter frames, consisting of a set of worlds equipped with an accessibility relation, and a free filter at every world. (shrink)

Carnap and Popper proposed ways scientists have to work. According to Carnap, they should look for confirmations for hypotheses. In Popper‘s view, what is important is to try to falsify hypotheses. Cognitive science seems to prove that, in real scientific research, both activities play a role. First, people attempt to confirm hypotheses. Second, they seek examples refuting those hypotheses. This paper is intended to show that the theory of mental models can describe the mental processes involved in both (...) tasks: confirmation and falsification. It addresses the mental possibilities individuals consider in both cases. In addition, the paper reveals that, in accordance with both Carnap‘s framework and Popper‘s approach, both mental activities are related to conditional reasoning. (shrink)

According to the standard story W. V. Quine ’s criticisms of the idea that logic is true by convention are directed against, and completely undermine, Rudolf Carnap’s idea that the logical truths of a language L are the sentences of L that are true-in- L solely in virtue of the linguistic conventions for L, and Quine himself had no interest in or use for any notion of truth by convention. This paper argues that and are both false. Carnap (...) did not endorse any truth -by- convention theses that are undermined by Quine ’s technical observations. Quine knew this. Quine ’s criticisms of the thesis that logic is true by convention are not directed against a truth -by- convention thesis that Carnap actually held, but are part of Quine ’s own project of articulating the consequences of his scientific naturalism. Quine found that logic is not true by convention in any naturalistically acceptable sense. But he also observed that in set theory and other highly abstract parts of science we sometimes deliberately adopt postulates with no justification other than that they are elegant and convenient. For Quine such postulations constitute a naturalistically acceptable and fallible sort of truth by convention. It is only when an act of adopting a postulate is not indispensible to natural science that Quine sees it as affording truth by convention ‘unalloyed’. A naturalist who accepts Quine ’s notion of truth by convention is therefore not limited to accepting only those postulates that she regards as indispensible to natural science. (shrink)